fs/btrfs/volumes.c

   1 /*
   2  * Copyright (C) 2007 Oracle.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18 #include <linux/sched.h>
  19 #include <linux/bio.h>
  20 #include <linux/slab.h>
  21 #include <linux/buffer_head.h>
  22 #include <linux/blkdev.h>
  23 #include <linux/iocontext.h>
  24 #include <linux/capability.h>
  25 #include <linux/ratelimit.h>
  26 #include <linux/kthread.h>
  27 #include <linux/raid/pq.h>
  28 #include <linux/semaphore.h>
  29 #include <linux/uuid.h>
  30 #include <asm/div64.h>
  31 #include "ctree.h"
  32 #include "extent_map.h"
  33 #include "disk-io.h"
  34 #include "transaction.h"
  35 #include "print-tree.h"
  36 #include "volumes.h"
  37 #include "raid56.h"
  38 #include "async-thread.h"
  39 #include "check-integrity.h"
  40 #include "rcu-string.h"
  41 #include "math.h"
  42 #include "dev-replace.h"
  43 #include "sysfs.h"
  44
  45 const struct btrfs_raid_attr btrfs_raid_array[BTRFS_NR_RAID_TYPES] = {
  46         [BTRFS_RAID_RAID10] = {
  47                 .sub_stripes    = 2,
  48                 .dev_stripes    = 1,
  49                 .devs_max       = 0,    /* 0 == as many as possible */
  50                 .devs_min       = 4,
  51                 .tolerated_failures = 1,
  52                 .devs_increment = 2,
  53                 .ncopies        = 2,
  54         },
  55         [BTRFS_RAID_RAID1] = {
  56                 .sub_stripes    = 1,
  57                 .dev_stripes    = 1,
  58                 .devs_max       = 2,
  59                 .devs_min       = 2,
  60                 .tolerated_failures = 1,
  61                 .devs_increment = 2,
  62                 .ncopies        = 2,
  63         },
  64         [BTRFS_RAID_DUP] = {
  65                 .sub_stripes    = 1,
  66                 .dev_stripes    = 2,
  67                 .devs_max       = 1,
  68                 .devs_min       = 1,
  69                 .tolerated_failures = 0,
  70                 .devs_increment = 1,
  71                 .ncopies        = 2,
  72         },
  73         [BTRFS_RAID_RAID0] = {
  74                 .sub_stripes    = 1,
  75                 .dev_stripes    = 1,
  76                 .devs_max       = 0,
  77                 .devs_min       = 2,
  78                 .tolerated_failures = 0,
  79                 .devs_increment = 1,
  80                 .ncopies        = 1,
  81         },
  82         [BTRFS_RAID_SINGLE] = {
  83                 .sub_stripes    = 1,
  84                 .dev_stripes    = 1,
  85                 .devs_max       = 1,
  86                 .devs_min       = 1,
  87                 .tolerated_failures = 0,
  88                 .devs_increment = 1,
  89                 .ncopies        = 1,
  90         },
  91         [BTRFS_RAID_RAID5] = {
  92                 .sub_stripes    = 1,
  93                 .dev_stripes    = 1,
  94                 .devs_max       = 0,
  95                 .devs_min       = 2,
  96                 .tolerated_failures = 1,
  97                 .devs_increment = 1,
  98                 .ncopies        = 2,
  99         },
 100         [BTRFS_RAID_RAID6] = {
 101                 .sub_stripes    = 1,
 102                 .dev_stripes    = 1,
 103                 .devs_max       = 0,
 104                 .devs_min       = 3,
 105                 .tolerated_failures = 2,
 106                 .devs_increment = 1,
 107                 .ncopies        = 3,
 108         },
 109 };
 110
 111 const u64 btrfs_raid_group[BTRFS_NR_RAID_TYPES] = {
 112         [BTRFS_RAID_RAID10] = BTRFS_BLOCK_GROUP_RAID10,
 113         [BTRFS_RAID_RAID1]  = BTRFS_BLOCK_GROUP_RAID1,
 114         [BTRFS_RAID_DUP]    = BTRFS_BLOCK_GROUP_DUP,
 115         [BTRFS_RAID_RAID0]  = BTRFS_BLOCK_GROUP_RAID0,
 116         [BTRFS_RAID_SINGLE] = 0,
 117         [BTRFS_RAID_RAID5]  = BTRFS_BLOCK_GROUP_RAID5,
 118         [BTRFS_RAID_RAID6]  = BTRFS_BLOCK_GROUP_RAID6,
 119 };
 120
 121 /*
 122  * Table to convert BTRFS_RAID_* to the error code if minimum number of devices
 123  * condition is not met. Zero means there's no corresponding
 124  * BTRFS_ERROR_DEV_*_NOT_MET value.
 125  */
 126 const int btrfs_raid_mindev_error[BTRFS_NR_RAID_TYPES] = {
 127         [BTRFS_RAID_RAID10] = BTRFS_ERROR_DEV_RAID10_MIN_NOT_MET,
 128         [BTRFS_RAID_RAID1]  = BTRFS_ERROR_DEV_RAID1_MIN_NOT_MET,
 129         [BTRFS_RAID_DUP]    = 0,
 130         [BTRFS_RAID_RAID0]  = 0,
 131         [BTRFS_RAID_SINGLE] = 0,
 132         [BTRFS_RAID_RAID5]  = BTRFS_ERROR_DEV_RAID5_MIN_NOT_MET,
 133         [BTRFS_RAID_RAID6]  = BTRFS_ERROR_DEV_RAID6_MIN_NOT_MET,
 134 };
 135
 136 static int init_first_rw_device(struct btrfs_trans_handle *trans,
 137                                 struct btrfs_fs_info *fs_info);
 138 static int btrfs_relocate_sys_chunks(struct btrfs_fs_info *fs_info);
 139 static void __btrfs_reset_dev_stats(struct btrfs_device *dev);
 140 static void btrfs_dev_stat_print_on_error(struct btrfs_device *dev);
 141 static void btrfs_dev_stat_print_on_load(struct btrfs_device *device);
 142 static int __btrfs_map_block(struct btrfs_fs_info *fs_info,
 143                              enum btrfs_map_op op,
 144                              u64 logical, u64 *length,
 145                              struct btrfs_bio **bbio_ret,
 146                              int mirror_num, int need_raid_map);
 147
 148 DEFINE_MUTEX(uuid_mutex);
 149 static LIST_HEAD(fs_uuids);
 150 struct list_head *btrfs_get_fs_uuids(void)
 151 {
 152         return &fs_uuids;
 153 }
 154
 155 /*
 156  * alloc_fs_devices - allocate struct btrfs_fs_devices
 157  * @fsid:       if not NULL, copy the uuid to fs_devices::fsid
 158  *
 159  * Return a pointer to a new struct btrfs_fs_devices on success, or ERR_PTR().
 160  * The returned struct is not linked onto any lists and can be destroyed with
 161  * kfree() right away.
 162  */
 163 static struct btrfs_fs_devices *alloc_fs_devices(const u8 *fsid)
 164 {
 165         struct btrfs_fs_devices *fs_devs;
 166
 167         fs_devs = kzalloc(sizeof(*fs_devs), GFP_KERNEL);
 168         if (!fs_devs)
 169                 return ERR_PTR(-ENOMEM);
 170
 171         mutex_init(&fs_devs->device_list_mutex);
 172
 173         INIT_LIST_HEAD(&fs_devs->devices);
 174         INIT_LIST_HEAD(&fs_devs->resized_devices);
 175         INIT_LIST_HEAD(&fs_devs->alloc_list);
 176         INIT_LIST_HEAD(&fs_devs->list);
 177         if (fsid)
 178                 memcpy(fs_devs->fsid, fsid, BTRFS_FSID_SIZE);
 179
 180         return fs_devs;
 181 }
 182
 183 static void free_fs_devices(struct btrfs_fs_devices *fs_devices)
 184 {
 185         struct btrfs_device *device;
 186         WARN_ON(fs_devices->opened);
 187         while (!list_empty(&fs_devices->devices)) {
 188                 device = list_entry(fs_devices->devices.next,
 189                                     struct btrfs_device, dev_list);
 190                 list_del(&device->dev_list);
 191                 rcu_string_free(device->name);
 192                 bio_put(device->flush_bio);
 193                 kfree(device);
 194         }
 195         kfree(fs_devices);
 196 }
 197
 198 static void btrfs_kobject_uevent(struct block_device *bdev,
 199                                  enum kobject_action action)
 200 {
 201         int ret;
 202
 203         ret = kobject_uevent(&disk_to_dev(bdev->bd_disk)->kobj, action);
 204         if (ret)
 205                 pr_warn("BTRFS: Sending event '%d' to kobject: '%s' (%p): failed\n",
 206                         action,
 207                         kobject_name(&disk_to_dev(bdev->bd_disk)->kobj),
 208                         &disk_to_dev(bdev->bd_disk)->kobj);
 209 }
 210
 211 void btrfs_cleanup_fs_uuids(void)
 212 {
 213         struct btrfs_fs_devices *fs_devices;
 214
 215         while (!list_empty(&fs_uuids)) {
 216                 fs_devices = list_entry(fs_uuids.next,
 217                                         struct btrfs_fs_devices, list);
 218                 list_del(&fs_devices->list);
 219                 free_fs_devices(fs_devices);
 220         }
 221 }
 222
 223 static struct btrfs_device *__alloc_device(void)
 224 {
 225         struct btrfs_device *dev;
 226
 227         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
 228         if (!dev)
 229                 return ERR_PTR(-ENOMEM);
 230
 231         /*
 232          * Preallocate a bio that's always going to be used for flushing device
 233          * barriers and matches the device lifespan
 234          */
 235         dev->flush_bio = bio_alloc_bioset(GFP_KERNEL, 0, NULL);
 236         if (!dev->flush_bio) {
 237                 kfree(dev);
 238                 return ERR_PTR(-ENOMEM);
 239         }
 240         bio_get(dev->flush_bio);
 241
 242         INIT_LIST_HEAD(&dev->dev_list);
 243         INIT_LIST_HEAD(&dev->dev_alloc_list);
 244         INIT_LIST_HEAD(&dev->resized_list);
 245
 246         spin_lock_init(&dev->io_lock);
 247
 248         spin_lock_init(&dev->reada_lock);
 249         atomic_set(&dev->reada_in_flight, 0);
 250         atomic_set(&dev->dev_stats_ccnt, 0);
 251         btrfs_device_data_ordered_init(dev);
 252         INIT_RADIX_TREE(&dev->reada_zones, GFP_NOFS & ~__GFP_DIRECT_RECLAIM);
 253         INIT_RADIX_TREE(&dev->reada_extents, GFP_NOFS & ~__GFP_DIRECT_RECLAIM);
 254
 255         return dev;
 256 }
 257
 258 /*
 259  * Find a device specified by @devid or @uuid in the list of @fs_devices, or
 260  * return NULL.
 261  *
 262  * If devid and uuid are both specified, the match must be exact, otherwise
 263  * only devid is used.
 264  */
 265 static struct btrfs_device *find_device(struct btrfs_fs_devices *fs_devices,
 266                 u64 devid, const u8 *uuid)
 267 {
 268         struct list_head *head = &fs_devices->devices;
 269         struct btrfs_device *dev;
 270
 271         list_for_each_entry(dev, head, dev_list) {
 272                 if (dev->devid == devid &&
 273                     (!uuid || !memcmp(dev->uuid, uuid, BTRFS_UUID_SIZE))) {
 274                         return dev;
 275                 }
 276         }
 277         return NULL;
 278 }
 279
 280 static noinline struct btrfs_fs_devices *find_fsid(u8 *fsid)
 281 {
 282         struct btrfs_fs_devices *fs_devices;
 283
 284         list_for_each_entry(fs_devices, &fs_uuids, list) {
 285                 if (memcmp(fsid, fs_devices->fsid, BTRFS_FSID_SIZE) == 0)
 286                         return fs_devices;
 287         }
 288         return NULL;
 289 }
 290
 291 static int
 292 btrfs_get_bdev_and_sb(const char *device_path, fmode_t flags, void *holder,
 293                       int flush, struct block_device **bdev,
 294                       struct buffer_head **bh)
 295 {
 296         int ret;
 297
 298         *bdev = blkdev_get_by_path(device_path, flags, holder);
 299
 300         if (IS_ERR(*bdev)) {
 301                 ret = PTR_ERR(*bdev);
 302                 goto error;
 303         }
 304
 305         if (flush)
 306                 filemap_write_and_wait((*bdev)->bd_inode->i_mapping);
 307         ret = set_blocksize(*bdev, BTRFS_BDEV_BLOCKSIZE);
 308         if (ret) {
 309                 blkdev_put(*bdev, flags);
 310                 goto error;
 311         }
 312         invalidate_bdev(*bdev);
 313         *bh = btrfs_read_dev_super(*bdev);
 314         if (IS_ERR(*bh)) {
 315                 ret = PTR_ERR(*bh);
 316                 blkdev_put(*bdev, flags);
 317                 goto error;
 318         }
 319
 320         return 0;
 321
 322 error:
 323         *bdev = NULL;
 324         *bh = NULL;
 325         return ret;
 326 }
 327
 328 static void requeue_list(struct btrfs_pending_bios *pending_bios,
 329                         struct bio *head, struct bio *tail)
 330 {
 331
 332         struct bio *old_head;
 333
 334         old_head = pending_bios->head;
 335         pending_bios->head = head;
 336         if (pending_bios->tail)
 337                 tail->bi_next = old_head;
 338         else
 339                 pending_bios->tail = tail;
 340 }
 341
 342 /*
 343  * we try to collect pending bios for a device so we don't get a large
 344  * number of procs sending bios down to the same device.  This greatly
 345  * improves the schedulers ability to collect and merge the bios.
 346  *
 347  * But, it also turns into a long list of bios to process and that is sure
 348  * to eventually make the worker thread block.  The solution here is to
 349  * make some progress and then put this work struct back at the end of
 350  * the list if the block device is congested.  This way, multiple devices
 351  * can make progress from a single worker thread.
 352  */
 353 static noinline void run_scheduled_bios(struct btrfs_device *device)
 354 {
 355         struct btrfs_fs_info *fs_info = device->fs_info;
 356         struct bio *pending;
 357         struct backing_dev_info *bdi;
 358         struct btrfs_pending_bios *pending_bios;
 359         struct bio *tail;
 360         struct bio *cur;
 361         int again = 0;
 362         unsigned long num_run;
 363         unsigned long batch_run = 0;
 364         unsigned long last_waited = 0;
 365         int force_reg = 0;
 366         int sync_pending = 0;
 367         struct blk_plug plug;
 368
 369         /*
 370          * this function runs all the bios we've collected for
 371          * a particular device.  We don't want to wander off to
 372          * another device without first sending all of these down.
 373          * So, setup a plug here and finish it off before we return
 374          */
 375         blk_start_plug(&plug);
 376
 377         bdi = device->bdev->bd_bdi;
 378
 379 loop:
 380         spin_lock(&device->io_lock);
 381
 382 loop_lock:
 383         num_run = 0;
 384
 385         /* take all the bios off the list at once and process them
 386          * later on (without the lock held).  But, remember the
 387          * tail and other pointers so the bios can be properly reinserted
 388          * into the list if we hit congestion
 389          */
 390         if (!force_reg && device->pending_sync_bios.head) {
 391                 pending_bios = &device->pending_sync_bios;
 392                 force_reg = 1;
 393         } else {
 394                 pending_bios = &device->pending_bios;
 395                 force_reg = 0;
 396         }
 397
 398         pending = pending_bios->head;
 399         tail = pending_bios->tail;
 400         WARN_ON(pending && !tail);
 401
 402         /*
 403          * if pending was null this time around, no bios need processing
 404          * at all and we can stop.  Otherwise it'll loop back up again
 405          * and do an additional check so no bios are missed.
 406          *
 407          * device->running_pending is used to synchronize with the
 408          * schedule_bio code.
 409          */
 410         if (device->pending_sync_bios.head == NULL &&
 411             device->pending_bios.head == NULL) {
 412                 again = 0;
 413                 device->running_pending = 0;
 414         } else {
 415                 again = 1;
 416                 device->running_pending = 1;
 417         }
 418
 419         pending_bios->head = NULL;
 420         pending_bios->tail = NULL;
 421
 422         spin_unlock(&device->io_lock);
 423
 424         while (pending) {
 425
 426                 rmb();
 427                 /* we want to work on both lists, but do more bios on the
 428                  * sync list than the regular list
 429                  */
 430                 if ((num_run > 32 &&
 431                     pending_bios != &device->pending_sync_bios &&
 432                     device->pending_sync_bios.head) ||
 433                    (num_run > 64 && pending_bios == &device->pending_sync_bios &&
 434                     device->pending_bios.head)) {
 435                         spin_lock(&device->io_lock);
 436                         requeue_list(pending_bios, pending, tail);
 437                         goto loop_lock;
 438                 }
 439
 440                 cur = pending;
 441                 pending = pending->bi_next;
 442                 cur->bi_next = NULL;
 443
 444                 BUG_ON(atomic_read(&cur->__bi_cnt) == 0);
 445
 446                 /*
 447                  * if we're doing the sync list, record that our
 448                  * plug has some sync requests on it
 449                  *
 450                  * If we're doing the regular list and there are
 451                  * sync requests sitting around, unplug before
 452                  * we add more
 453                  */
 454                 if (pending_bios == &device->pending_sync_bios) {
 455                         sync_pending = 1;
 456                 } else if (sync_pending) {
 457                         blk_finish_plug(&plug);
 458                         blk_start_plug(&plug);
 459                         sync_pending = 0;
 460                 }
 461
 462                 btrfsic_submit_bio(cur);
 463                 num_run++;
 464                 batch_run++;
 465
 466                 cond_resched();
 467
 468                 /*
 469                  * we made progress, there is more work to do and the bdi
 470                  * is now congested.  Back off and let other work structs
 471                  * run instead
 472                  */
 473                 if (pending && bdi_write_congested(bdi) && batch_run > 8 &&
 474                     fs_info->fs_devices->open_devices > 1) {
 475                         struct io_context *ioc;
 476
 477                         ioc = current->io_context;
 478
 479                         /*
 480                          * the main goal here is that we don't want to
 481                          * block if we're going to be able to submit
 482                          * more requests without blocking.
 483                          *
 484                          * This code does two great things, it pokes into
 485                          * the elevator code from a filesystem _and_
 486                          * it makes assumptions about how batching works.
 487                          */
 488                         if (ioc && ioc->nr_batch_requests > 0 &&
 489                             time_before(jiffies, ioc->last_waited + HZ/50UL) &&
 490                             (last_waited == 0 ||
 491                              ioc->last_waited == last_waited)) {
 492                                 /*
 493                                  * we want to go through our batch of
 494                                  * requests and stop.  So, we copy out
 495                                  * the ioc->last_waited time and test
 496                                  * against it before looping
 497                                  */
 498                                 last_waited = ioc->last_waited;
 499                                 cond_resched();
 500                                 continue;
 501                         }
 502                         spin_lock(&device->io_lock);
 503                         requeue_list(pending_bios, pending, tail);
 504                         device->running_pending = 1;
 505
 506                         spin_unlock(&device->io_lock);
 507                         btrfs_queue_work(fs_info->submit_workers,
 508                                          &device->work);
 509                         goto done;
 510                 }
 511         }
 512
 513         cond_resched();
 514         if (again)
 515                 goto loop;
 516
 517         spin_lock(&device->io_lock);
 518         if (device->pending_bios.head || device->pending_sync_bios.head)
 519                 goto loop_lock;
 520         spin_unlock(&device->io_lock);
 521
 522 done:
 523         blk_finish_plug(&plug);
 524 }
 525
 526 static void pending_bios_fn(struct btrfs_work *work)
 527 {
 528         struct btrfs_device *device;
 529
 530         device = container_of(work, struct btrfs_device, work);
 531         run_scheduled_bios(device);
 532 }
 533
 534
 535 static void btrfs_free_stale_device(struct btrfs_device *cur_dev)
 536 {
 537         struct btrfs_fs_devices *fs_devs;
 538         struct btrfs_device *dev;
 539
 540         if (!cur_dev->name)
 541                 return;
 542
 543         list_for_each_entry(fs_devs, &fs_uuids, list) {
 544                 int del = 1;
 545
 546                 if (fs_devs->opened)
 547                         continue;
 548                 if (fs_devs->seeding)
 549                         continue;
 550
 551                 list_for_each_entry(dev, &fs_devs->devices, dev_list) {
 552
 553                         if (dev == cur_dev)
 554                                 continue;
 555                         if (!dev->name)
 556                                 continue;
 557
 558                         /*
 559                          * Todo: This won't be enough. What if the same device
 560                          * comes back (with new uuid and) with its mapper path?
 561                          * But for now, this does help as mostly an admin will
 562                          * either use mapper or non mapper path throughout.
 563                          */
 564                         rcu_read_lock();
 565                         del = strcmp(rcu_str_deref(dev->name),
 566                                                 rcu_str_deref(cur_dev->name));
 567                         rcu_read_unlock();
 568                         if (!del)
 569                                 break;
 570                 }
 571
 572                 if (!del) {
 573                         /* delete the stale device */
 574                         if (fs_devs->num_devices == 1) {
 575                                 btrfs_sysfs_remove_fsid(fs_devs);
 576                                 list_del(&fs_devs->list);
 577                                 free_fs_devices(fs_devs);
 578                         } else {
 579                                 fs_devs->num_devices--;
 580                                 list_del(&dev->dev_list);
 581                                 rcu_string_free(dev->name);
 582                                 bio_put(dev->flush_bio);
 583                                 kfree(dev);
 584                         }
 585                         break;
 586                 }
 587         }
 588 }
 589
 590 /*
 591  * Add new device to list of registered devices
 592  *
 593  * Returns:
 594  * 1   - first time device is seen
 595  * 0   - device already known
 596  * < 0 - error
 597  */
 598 static noinline int device_list_add(const char *path,
 599                            struct btrfs_super_block *disk_super,
 600                            u64 devid, struct btrfs_fs_devices **fs_devices_ret)
 601 {
 602         struct btrfs_device *device;
 603         struct btrfs_fs_devices *fs_devices;
 604         struct rcu_string *name;
 605         int ret = 0;
 606         u64 found_transid = btrfs_super_generation(disk_super);
 607
 608         fs_devices = find_fsid(disk_super->fsid);
 609         if (!fs_devices) {
 610                 fs_devices = alloc_fs_devices(disk_super->fsid);
 611                 if (IS_ERR(fs_devices))
 612                         return PTR_ERR(fs_devices);
 613
 614                 list_add(&fs_devices->list, &fs_uuids);
 615
 616                 device = NULL;
 617         } else {
 618                 device = find_device(fs_devices, devid,
 619                                 disk_super->dev_item.uuid);
 620         }
 621
 622         if (!device) {
 623                 if (fs_devices->opened)
 624                         return -EBUSY;
 625
 626                 device = btrfs_alloc_device(NULL, &devid,
 627                                             disk_super->dev_item.uuid);
 628                 if (IS_ERR(device)) {
 629                         /* we can safely leave the fs_devices entry around */
 630                         return PTR_ERR(device);
 631                 }
 632
 633                 name = rcu_string_strdup(path, GFP_NOFS);
 634                 if (!name) {
 635                         bio_put(device->flush_bio);
 636                         kfree(device);
 637                         return -ENOMEM;
 638                 }
 639                 rcu_assign_pointer(device->name, name);
 640
 641                 mutex_lock(&fs_devices->device_list_mutex);
 642                 list_add_rcu(&device->dev_list, &fs_devices->devices);
 643                 fs_devices->num_devices++;
 644                 mutex_unlock(&fs_devices->device_list_mutex);
 645
 646                 ret = 1;
 647                 device->fs_devices = fs_devices;
 648         } else if (!device->name || strcmp(device->name->str, path)) {
 649                 /*
 650                  * When FS is already mounted.
 651                  * 1. If you are here and if the device->name is NULL that
 652                  *    means this device was missing at time of FS mount.
 653                  * 2. If you are here and if the device->name is different
 654                  *    from 'path' that means either
 655                  *      a. The same device disappeared and reappeared with
 656                  *         different name. or
 657                  *      b. The missing-disk-which-was-replaced, has
 658                  *         reappeared now.
 659                  *
 660                  * We must allow 1 and 2a above. But 2b would be a spurious
 661                  * and unintentional.
 662                  *
 663                  * Further in case of 1 and 2a above, the disk at 'path'
 664                  * would have missed some transaction when it was away and
 665                  * in case of 2a the stale bdev has to be updated as well.
 666                  * 2b must not be allowed at all time.
 667                  */
 668
 669                 /*
 670                  * For now, we do allow update to btrfs_fs_device through the
 671                  * btrfs dev scan cli after FS has been mounted.  We're still
 672                  * tracking a problem where systems fail mount by subvolume id
 673                  * when we reject replacement on a mounted FS.
 674                  */
 675                 if (!fs_devices->opened && found_transid < device->generation) {
 676                         /*
 677                          * That is if the FS is _not_ mounted and if you
 678                          * are here, that means there is more than one
 679                          * disk with same uuid and devid.We keep the one
 680                          * with larger generation number or the last-in if
 681                          * generation are equal.
 682                          */
 683                         return -EEXIST;
 684                 }
 685
 686                 name = rcu_string_strdup(path, GFP_NOFS);
 687                 if (!name)
 688                         return -ENOMEM;
 689                 rcu_string_free(device->name);
 690                 rcu_assign_pointer(device->name, name);
 691                 if (device->missing) {
 692                         fs_devices->missing_devices--;
 693                         device->missing = 0;
 694                 }
 695         }
 696
 697         /*
 698          * Unmount does not free the btrfs_device struct but would zero
 699          * generation along with most of the other members. So just update
 700          * it back. We need it to pick the disk with largest generation
 701          * (as above).
 702          */
 703         if (!fs_devices->opened)
 704                 device->generation = found_transid;
 705
 706         /*
 707          * if there is new btrfs on an already registered device,
 708          * then remove the stale device entry.
 709          */
 710         if (ret > 0)
 711                 btrfs_free_stale_device(device);
 712
 713         *fs_devices_ret = fs_devices;
 714
 715         return ret;
 716 }
 717
 718 static struct btrfs_fs_devices *clone_fs_devices(struct btrfs_fs_devices *orig)
 719 {
 720         struct btrfs_fs_devices *fs_devices;
 721         struct btrfs_device *device;
 722         struct btrfs_device *orig_dev;
 723
 724         fs_devices = alloc_fs_devices(orig->fsid);
 725         if (IS_ERR(fs_devices))
 726                 return fs_devices;
 727
 728         mutex_lock(&orig->device_list_mutex);
 729         fs_devices->total_devices = orig->total_devices;
 730
 731         /* We have held the volume lock, it is safe to get the devices. */
 732         list_for_each_entry(orig_dev, &orig->devices, dev_list) {
 733                 struct rcu_string *name;
 734
 735                 device = btrfs_alloc_device(NULL, &orig_dev->devid,
 736                                             orig_dev->uuid);
 737                 if (IS_ERR(device))
 738                         goto error;
 739
 740                 /*
 741                  * This is ok to do without rcu read locked because we hold the
 742                  * uuid mutex so nothing we touch in here is going to disappear.
 743                  */
 744                 if (orig_dev->name) {
 745                         name = rcu_string_strdup(orig_dev->name->str,
 746                                         GFP_KERNEL);
 747                         if (!name) {
 748                                 bio_put(device->flush_bio);
 749                                 kfree(device);
 750                                 goto error;
 751                         }
 752                         rcu_assign_pointer(device->name, name);
 753                 }
 754
 755                 list_add(&device->dev_list, &fs_devices->devices);
 756                 device->fs_devices = fs_devices;
 757                 fs_devices->num_devices++;
 758         }
 759         mutex_unlock(&orig->device_list_mutex);
 760         return fs_devices;
 761 error:
 762         mutex_unlock(&orig->device_list_mutex);
 763         free_fs_devices(fs_devices);
 764         return ERR_PTR(-ENOMEM);
 765 }
 766
 767 void btrfs_close_extra_devices(struct btrfs_fs_devices *fs_devices, int step)
 768 {
 769         struct btrfs_device *device, *next;
 770         struct btrfs_device *latest_dev = NULL;
 771
 772         mutex_lock(&uuid_mutex);
 773 again:
 774         /* This is the initialized path, it is safe to release the devices. */
 775         list_for_each_entry_safe(device, next, &fs_devices->devices, dev_list) {
 776                 if (device->in_fs_metadata) {
 777                         if (!device->is_tgtdev_for_dev_replace &&
 778                             (!latest_dev ||
 779                              device->generation > latest_dev->generation)) {
 780                                 latest_dev = device;
 781                         }
 782                         continue;
 783                 }
 784
 785                 if (device->devid == BTRFS_DEV_REPLACE_DEVID) {
 786                         /*
 787                          * In the first step, keep the device which has
 788                          * the correct fsid and the devid that is used
 789                          * for the dev_replace procedure.
 790                          * In the second step, the dev_replace state is
 791                          * read from the device tree and it is known
 792                          * whether the procedure is really active or
 793                          * not, which means whether this device is
 794                          * used or whether it should be removed.
 795                          */
 796                         if (step == 0 || device->is_tgtdev_for_dev_replace) {
 797                                 continue;
 798                         }
 799                 }
 800                 if (device->bdev) {
 801                         blkdev_put(device->bdev, device->mode);
 802                         device->bdev = NULL;
 803                         fs_devices->open_devices--;
 804                 }
 805                 if (device->writeable) {
 806                         list_del_init(&device->dev_alloc_list);
 807                         device->writeable = 0;
 808                         if (!device->is_tgtdev_for_dev_replace)
 809                                 fs_devices->rw_devices--;
 810                 }
 811                 list_del_init(&device->dev_list);
 812                 fs_devices->num_devices--;
 813                 rcu_string_free(device->name);
 814                 bio_put(device->flush_bio);
 815                 kfree(device);
 816         }
 817
 818         if (fs_devices->seed) {
 819                 fs_devices = fs_devices->seed;
 820                 goto again;
 821         }
 822
 823         fs_devices->latest_bdev = latest_dev->bdev;
 824
 825         mutex_unlock(&uuid_mutex);
 826 }
 827
 828 static void __free_device(struct work_struct *work)
 829 {
 830         struct btrfs_device *device;
 831
 832         device = container_of(work, struct btrfs_device, rcu_work);
 833         rcu_string_free(device->name);
 834         bio_put(device->flush_bio);
 835         kfree(device);
 836 }
 837
 838 static void free_device(struct rcu_head *head)
 839 {
 840         struct btrfs_device *device;
 841
 842         device = container_of(head, struct btrfs_device, rcu);
 843
 844         INIT_WORK(&device->rcu_work, __free_device);
 845         schedule_work(&device->rcu_work);
 846 }
 847
 848 static void btrfs_close_bdev(struct btrfs_device *device)
 849 {
 850         if (device->bdev && device->writeable) {
 851                 sync_blockdev(device->bdev);
 852                 invalidate_bdev(device->bdev);
 853         }
 854
 855         if (device->bdev)
 856                 blkdev_put(device->bdev, device->mode);
 857 }
 858
 859 static void btrfs_prepare_close_one_device(struct btrfs_device *device)
 860 {
 861         struct btrfs_fs_devices *fs_devices = device->fs_devices;
 862         struct btrfs_device *new_device;
 863         struct rcu_string *name;
 864
 865         if (device->bdev)
 866                 fs_devices->open_devices--;
 867
 868         if (device->writeable &&
 869             device->devid != BTRFS_DEV_REPLACE_DEVID) {
 870                 list_del_init(&device->dev_alloc_list);
 871                 fs_devices->rw_devices--;
 872         }
 873
 874         if (device->missing)
 875                 fs_devices->missing_devices--;
 876
 877         new_device = btrfs_alloc_device(NULL, &device->devid,
 878                                         device->uuid);
 879         BUG_ON(IS_ERR(new_device)); /* -ENOMEM */
 880
 881         /* Safe because we are under uuid_mutex */
 882         if (device->name) {
 883                 name = rcu_string_strdup(device->name->str, GFP_NOFS);
 884                 BUG_ON(!name); /* -ENOMEM */
 885                 rcu_assign_pointer(new_device->name, name);
 886         }
 887
 888         list_replace_rcu(&device->dev_list, &new_device->dev_list);
 889         new_device->fs_devices = device->fs_devices;
 890 }
 891
 892 static int __btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
 893 {
 894         struct btrfs_device *device, *tmp;
 895         struct list_head pending_put;
 896
 897         INIT_LIST_HEAD(&pending_put);
 898
 899         if (--fs_devices->opened > 0)
 900                 return 0;
 901
 902         mutex_lock(&fs_devices->device_list_mutex);
 903         list_for_each_entry_safe(device, tmp, &fs_devices->devices, dev_list) {
 904                 btrfs_prepare_close_one_device(device);
 905                 list_add(&device->dev_list, &pending_put);
 906         }
 907         mutex_unlock(&fs_devices->device_list_mutex);
 908
 909         /*
 910          * btrfs_show_devname() is using the device_list_mutex,
 911          * sometimes call to blkdev_put() leads vfs calling
 912          * into this func. So do put outside of device_list_mutex,
 913          * as of now.
 914          */
 915         while (!list_empty(&pending_put)) {
 916                 device = list_first_entry(&pending_put,
 917                                 struct btrfs_device, dev_list);
 918                 list_del(&device->dev_list);
 919                 btrfs_close_bdev(device);
 920                 call_rcu(&device->rcu, free_device);
 921         }
 922
 923         WARN_ON(fs_devices->open_devices);
 924         WARN_ON(fs_devices->rw_devices);
 925         fs_devices->opened = 0;
 926         fs_devices->seeding = 0;
 927
 928         return 0;
 929 }
 930
 931 int btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
 932 {
 933         struct btrfs_fs_devices *seed_devices = NULL;
 934         int ret;
 935
 936         mutex_lock(&uuid_mutex);
 937         ret = __btrfs_close_devices(fs_devices);
 938         if (!fs_devices->opened) {
 939                 seed_devices = fs_devices->seed;
 940                 fs_devices->seed = NULL;
 941         }
 942         mutex_unlock(&uuid_mutex);
 943
 944         while (seed_devices) {
 945                 fs_devices = seed_devices;
 946                 seed_devices = fs_devices->seed;
 947                 __btrfs_close_devices(fs_devices);
 948                 free_fs_devices(fs_devices);
 949         }
 950         /*
 951          * Wait for rcu kworkers under __btrfs_close_devices
 952          * to finish all blkdev_puts so device is really
 953          * free when umount is done.
 954          */
 955         rcu_barrier();
 956         return ret;
 957 }
 958
 959 static int __btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
 960                                 fmode_t flags, void *holder)
 961 {
 962         struct request_queue *q;
 963         struct block_device *bdev;
 964         struct list_head *head = &fs_devices->devices;
 965         struct btrfs_device *device;
 966         struct btrfs_device *latest_dev = NULL;
 967         struct buffer_head *bh;
 968         struct btrfs_super_block *disk_super;
 969         u64 devid;
 970         int seeding = 1;
 971         int ret = 0;
 972
 973         flags |= FMODE_EXCL;
 974
 975         list_for_each_entry(device, head, dev_list) {
 976                 if (device->bdev)
 977                         continue;
 978                 if (!device->name)
 979                         continue;
 980
 981                 /* Just open everything we can; ignore failures here */
 982                 if (btrfs_get_bdev_and_sb(device->name->str, flags, holder, 1,
 983                                             &bdev, &bh))
 984                         continue;
 985
 986                 disk_super = (struct btrfs_super_block *)bh->b_data;
 987                 devid = btrfs_stack_device_id(&disk_super->dev_item);
 988                 if (devid != device->devid)
 989                         goto error_brelse;
 990
 991                 if (memcmp(device->uuid, disk_super->dev_item.uuid,
 992                            BTRFS_UUID_SIZE))
 993                         goto error_brelse;
 994
 995                 device->generation = btrfs_super_generation(disk_super);
 996                 if (!latest_dev ||
 997                     device->generation > latest_dev->generation)
 998                         latest_dev = device;
 999
1000                 if (btrfs_super_flags(disk_super) & BTRFS_SUPER_FLAG_SEEDING) {
1001                         device->writeable = 0;
1002                 } else {
1003                         device->writeable = !bdev_read_only(bdev);
1004                         seeding = 0;
1005                 }
1006
1007                 q = bdev_get_queue(bdev);
1008                 if (blk_queue_discard(q))
1009                         device->can_discard = 1;
1010                 if (!blk_queue_nonrot(q))
1011                         fs_devices->rotating = 1;
1012
1013                 device->bdev = bdev;
1014                 device->in_fs_metadata = 0;
1015                 device->mode = flags;
1016
1017                 fs_devices->open_devices++;
1018                 if (device->writeable &&
1019                     device->devid != BTRFS_DEV_REPLACE_DEVID) {
1020                         fs_devices->rw_devices++;
1021                         list_add(&device->dev_alloc_list,
1022                                  &fs_devices->alloc_list);
1023                 }
1024                 brelse(bh);
1025                 continue;
1026
1027 error_brelse:
1028                 brelse(bh);
1029                 blkdev_put(bdev, flags);
1030                 continue;
1031         }
1032         if (fs_devices->open_devices == 0) {
1033                 ret = -EINVAL;
1034                 goto out;
1035         }
1036         fs_devices->seeding = seeding;
1037         fs_devices->opened = 1;
1038         fs_devices->latest_bdev = latest_dev->bdev;
1039         fs_devices->total_rw_bytes = 0;
1040 out:
1041         return ret;
1042 }
1043
1044 int btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
1045                        fmode_t flags, void *holder)
1046 {
1047         int ret;
1048
1049         mutex_lock(&uuid_mutex);
1050         if (fs_devices->opened) {
1051                 fs_devices->opened++;
1052                 ret = 0;
1053         } else {
1054                 ret = __btrfs_open_devices(fs_devices, flags, holder);
1055         }
1056         mutex_unlock(&uuid_mutex);
1057         return ret;
1058 }
1059
1060 static void btrfs_release_disk_super(struct page *page)
1061 {
1062         kunmap(page);
1063         put_page(page);
1064 }
1065
1066 static int btrfs_read_disk_super(struct block_device *bdev, u64 bytenr,
1067                                  struct page **page,
1068                                  struct btrfs_super_block **disk_super)
1069 {
1070         void *p;
1071         pgoff_t index;
1072
1073         /* make sure our super fits in the device */
1074         if (bytenr + PAGE_SIZE >= i_size_read(bdev->bd_inode))
1075                 return 1;
1076
1077         /* make sure our super fits in the page */
1078         if (sizeof(**disk_super) > PAGE_SIZE)
1079                 return 1;
1080
1081         /* make sure our super doesn't straddle pages on disk */
1082         index = bytenr >> PAGE_SHIFT;
1083         if ((bytenr + sizeof(**disk_super) - 1) >> PAGE_SHIFT != index)
1084                 return 1;
1085
1086         /* pull in the page with our super */
1087         *page = read_cache_page_gfp(bdev->bd_inode->i_mapping,
1088                                    index, GFP_KERNEL);
1089
1090         if (IS_ERR_OR_NULL(*page))
1091                 return 1;
1092
1093         p = kmap(*page);
1094
1095         /* align our pointer to the offset of the super block */
1096         *disk_super = p + (bytenr & ~PAGE_MASK);
1097
1098         if (btrfs_super_bytenr(*disk_super) != bytenr ||
1099             btrfs_super_magic(*disk_super) != BTRFS_MAGIC) {
1100                 btrfs_release_disk_super(*page);
1101                 return 1;
1102         }
1103
1104         if ((*disk_super)->label[0] &&
1105                 (*disk_super)->label[BTRFS_LABEL_SIZE - 1])
1106                 (*disk_super)->label[BTRFS_LABEL_SIZE - 1] = '\0';
1107
1108         return 0;
1109 }
1110
1111 /*
1112  * Look for a btrfs signature on a device. This may be called out of the mount path
1113  * and we are not allowed to call set_blocksize during the scan. The superblock
1114  * is read via pagecache
1115  */
1116 int btrfs_scan_one_device(const char *path, fmode_t flags, void *holder,
1117                           struct btrfs_fs_devices **fs_devices_ret)
1118 {
1119         struct btrfs_super_block *disk_super;
1120         struct block_device *bdev;
1121         struct page *page;
1122         int ret = -EINVAL;
1123         u64 devid;
1124         u64 transid;
1125         u64 total_devices;
1126         u64 bytenr;
1127
1128         /*
1129          * we would like to check all the supers, but that would make
1130          * a btrfs mount succeed after a mkfs from a different FS.
1131          * So, we need to add a special mount option to scan for
1132          * later supers, using BTRFS_SUPER_MIRROR_MAX instead
1133          */
1134         bytenr = btrfs_sb_offset(0);
1135         flags |= FMODE_EXCL;
1136         mutex_lock(&uuid_mutex);
1137
1138         bdev = blkdev_get_by_path(path, flags, holder);
1139         if (IS_ERR(bdev)) {
1140                 ret = PTR_ERR(bdev);
1141                 goto error;
1142         }
1143
1144         if (btrfs_read_disk_super(bdev, bytenr, &page, &disk_super))
1145                 goto error_bdev_put;
1146
1147         devid = btrfs_stack_device_id(&disk_super->dev_item);
1148         transid = btrfs_super_generation(disk_super);
1149         total_devices = btrfs_super_num_devices(disk_super);
1150
1151         ret = device_list_add(path, disk_super, devid, fs_devices_ret);
1152         if (ret > 0) {
1153                 if (disk_super->label[0]) {
1154                         pr_info("BTRFS: device label %s ", disk_super->label);
1155                 } else {
1156                         pr_info("BTRFS: device fsid %pU ", disk_super->fsid);
1157                 }
1158
1159                 pr_cont("devid %llu transid %llu %s\n", devid, transid, path);
1160                 ret = 0;
1161         }
1162         if (!ret && fs_devices_ret)
1163                 (*fs_devices_ret)->total_devices = total_devices;
1164
1165         btrfs_release_disk_super(page);
1166
1167 error_bdev_put:
1168         blkdev_put(bdev, flags);
1169 error:
1170         mutex_unlock(&uuid_mutex);
1171         return ret;
1172 }
1173
1174 /* helper to account the used device space in the range */
1175 int btrfs_account_dev_extents_size(struct btrfs_device *device, u64 start,
1176                                    u64 end, u64 *length)
1177 {
1178         struct btrfs_key key;
1179         struct btrfs_root *root = device->fs_info->dev_root;
1180         struct btrfs_dev_extent *dev_extent;
1181         struct btrfs_path *path;
1182         u64 extent_end;
1183         int ret;
1184         int slot;
1185         struct extent_buffer *l;
1186
1187         *length = 0;
1188
1189         if (start >= device->total_bytes || device->is_tgtdev_for_dev_replace)
1190                 return 0;
1191
1192         path = btrfs_alloc_path();
1193         if (!path)
1194                 return -ENOMEM;
1195         path->reada = READA_FORWARD;
1196
1197         key.objectid = device->devid;
1198         key.offset = start;
1199         key.type = BTRFS_DEV_EXTENT_KEY;
1200
1201         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1202         if (ret < 0)
1203                 goto out;
1204         if (ret > 0) {
1205                 ret = btrfs_previous_item(root, path, key.objectid, key.type);
1206                 if (ret < 0)
1207                         goto out;
1208         }
1209
1210         while (1) {
1211                 l = path->nodes[0];
1212                 slot = path->slots[0];
1213                 if (slot >= btrfs_header_nritems(l)) {
1214                         ret = btrfs_next_leaf(root, path);
1215                         if (ret == 0)
1216                                 continue;
1217                         if (ret < 0)
1218                                 goto out;
1219
1220                         break;
1221                 }
1222                 btrfs_item_key_to_cpu(l, &key, slot);
1223
1224                 if (key.objectid < device->devid)
1225                         goto next;
1226
1227                 if (key.objectid > device->devid)
1228                         break;
1229
1230                 if (key.type != BTRFS_DEV_EXTENT_KEY)
1231                         goto next;
1232
1233                 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
1234                 extent_end = key.offset + btrfs_dev_extent_length(l,
1235                                                                   dev_extent);
1236                 if (key.offset <= start && extent_end > end) {
1237                         *length = end - start + 1;
1238                         break;
1239                 } else if (key.offset <= start && extent_end > start)
1240                         *length += extent_end - start;
1241                 else if (key.offset > start && extent_end <= end)
1242                         *length += extent_end - key.offset;
1243                 else if (key.offset > start && key.offset <= end) {
1244                         *length += end - key.offset + 1;
1245                         break;
1246                 } else if (key.offset > end)
1247                         break;
1248
1249 next:
1250                 path->slots[0]++;
1251         }
1252         ret = 0;
1253 out:
1254         btrfs_free_path(path);
1255         return ret;
1256 }
1257
1258 static int contains_pending_extent(struct btrfs_transaction *transaction,
1259                                    struct btrfs_device *device,
1260                                    u64 *start, u64 len)
1261 {
1262         struct btrfs_fs_info *fs_info = device->fs_info;
1263         struct extent_map *em;
1264         struct list_head *search_list = &fs_info->pinned_chunks;
1265         int ret = 0;
1266         u64 physical_start = *start;
1267
1268         if (transaction)
1269                 search_list = &transaction->pending_chunks;
1270 again:
1271         list_for_each_entry(em, search_list, list) {
1272                 struct map_lookup *map;
1273                 int i;
1274
1275                 map = em->map_lookup;
1276                 for (i = 0; i < map->num_stripes; i++) {
1277                         u64 end;
1278
1279                         if (map->stripes[i].dev != device)
1280                                 continue;
1281                         if (map->stripes[i].physical >= physical_start + len ||
1282                             map->stripes[i].physical + em->orig_block_len <=
1283                             physical_start)
1284                                 continue;
1285                         /*
1286                          * Make sure that while processing the pinned list we do
1287                          * not override our *start with a lower value, because
1288                          * we can have pinned chunks that fall within this
1289                          * device hole and that have lower physical addresses
1290                          * than the pending chunks we processed before. If we
1291                          * do not take this special care we can end up getting
1292                          * 2 pending chunks that start at the same physical
1293                          * device offsets because the end offset of a pinned
1294                          * chunk can be equal to the start offset of some
1295                          * pending chunk.
1296                          */
1297                         end = map->stripes[i].physical + em->orig_block_len;
1298                         if (end > *start) {
1299                                 *start = end;
1300                                 ret = 1;
1301                         }
1302                 }
1303         }
1304         if (search_list != &fs_info->pinned_chunks) {
1305                 search_list = &fs_info->pinned_chunks;
1306                 goto again;
1307         }
1308
1309         return ret;
1310 }
1311
1312
1313 /*
1314  * find_free_dev_extent_start - find free space in the specified device
1315  * @device:       the device which we search the free space in
1316  * @num_bytes:    the size of the free space that we need
1317  * @search_start: the position from which to begin the search
1318  * @start:        store the start of the free space.
1319  * @len:          the size of the free space. that we find, or the size
1320  *                of the max free space if we don't find suitable free space
1321  *
1322  * this uses a pretty simple search, the expectation is that it is
1323  * called very infrequently and that a given device has a small number
1324  * of extents
1325  *
1326  * @start is used to store the start of the free space if we find. But if we
1327  * don't find suitable free space, it will be used to store the start position
1328  * of the max free space.
1329  *
1330  * @len is used to store the size of the free space that we find.
1331  * But if we don't find suitable free space, it is used to store the size of
1332  * the max free space.
1333  */
1334 int find_free_dev_extent_start(struct btrfs_transaction *transaction,
1335                                struct btrfs_device *device, u64 num_bytes,
1336                                u64 search_start, u64 *start, u64 *len)
1337 {
1338         struct btrfs_fs_info *fs_info = device->fs_info;
1339         struct btrfs_root *root = fs_info->dev_root;
1340         struct btrfs_key key;
1341         struct btrfs_dev_extent *dev_extent;
1342         struct btrfs_path *path;
1343         u64 hole_size;
1344         u64 max_hole_start;
1345         u64 max_hole_size;
1346         u64 extent_end;
1347         u64 search_end = device->total_bytes;
1348         int ret;
1349         int slot;
1350         struct extent_buffer *l;
1351
1352         /*
1353          * We don't want to overwrite the superblock on the drive nor any area
1354          * used by the boot loader (grub for example), so we make sure to start
1355          * at an offset of at least 1MB.
1356          */
1357         search_start = max_t(u64, search_start, SZ_1M);
1358
1359         path = btrfs_alloc_path();
1360         if (!path)
1361                 return -ENOMEM;
1362
1363         max_hole_start = search_start;
1364         max_hole_size = 0;
1365
1366 again:
1367         if (search_start >= search_end || device->is_tgtdev_for_dev_replace) {
1368                 ret = -ENOSPC;
1369                 goto out;
1370         }
1371
1372         path->reada = READA_FORWARD;
1373         path->search_commit_root = 1;
1374         path->skip_locking = 1;
1375
1376         key.objectid = device->devid;
1377         key.offset = search_start;
1378         key.type = BTRFS_DEV_EXTENT_KEY;
1379
1380         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1381         if (ret < 0)
1382                 goto out;
1383         if (ret > 0) {
1384                 ret = btrfs_previous_item(root, path, key.objectid, key.type);
1385                 if (ret < 0)
1386                         goto out;
1387         }
1388
1389         while (1) {
1390                 l = path->nodes[0];
1391                 slot = path->slots[0];
1392                 if (slot >= btrfs_header_nritems(l)) {
1393                         ret = btrfs_next_leaf(root, path);
1394                         if (ret == 0)
1395                                 continue;
1396                         if (ret < 0)
1397                                 goto out;
1398
1399                         break;
1400                 }
1401                 btrfs_item_key_to_cpu(l, &key, slot);
1402
1403                 if (key.objectid < device->devid)
1404                         goto next;
1405
1406                 if (key.objectid > device->devid)
1407                         break;
1408
1409                 if (key.type != BTRFS_DEV_EXTENT_KEY)
1410                         goto next;
1411
1412                 if (key.offset > search_start) {
1413                         hole_size = key.offset - search_start;
1414
1415                         /*
1416                          * Have to check before we set max_hole_start, otherwise
1417                          * we could end up sending back this offset anyway.
1418                          */
1419                         if (contains_pending_extent(transaction, device,
1420                                                     &search_start,
1421                                                     hole_size)) {
1422                                 if (key.offset >= search_start) {
1423                                         hole_size = key.offset - search_start;
1424                                 } else {
1425                                         WARN_ON_ONCE(1);
1426                                         hole_size = 0;
1427                                 }
1428                         }
1429
1430                         if (hole_size > max_hole_size) {
1431                                 max_hole_start = search_start;
1432                                 max_hole_size = hole_size;
1433                         }
1434
1435                         /*
1436                          * If this free space is greater than which we need,
1437                          * it must be the max free space that we have found
1438                          * until now, so max_hole_start must point to the start
1439                          * of this free space and the length of this free space
1440                          * is stored in max_hole_size. Thus, we return
1441                          * max_hole_start and max_hole_size and go back to the
1442                          * caller.
1443                          */
1444                         if (hole_size >= num_bytes) {
1445                                 ret = 0;
1446                                 goto out;
1447                         }
1448                 }
1449
1450                 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
1451                 extent_end = key.offset + btrfs_dev_extent_length(l,
1452                                                                   dev_extent);
1453                 if (extent_end > search_start)
1454                         search_start = extent_end;
1455 next:
1456                 path->slots[0]++;
1457                 cond_resched();
1458         }
1459
1460         /*
1461          * At this point, search_start should be the end of
1462          * allocated dev extents, and when shrinking the device,
1463          * search_end may be smaller than search_start.
1464          */
1465         if (search_end > search_start) {
1466                 hole_size = search_end - search_start;
1467
1468                 if (contains_pending_extent(transaction, device, &search_start,
1469                                             hole_size)) {
1470                         btrfs_release_path(path);
1471                         goto again;
1472                 }
1473
1474                 if (hole_size > max_hole_size) {
1475                         max_hole_start = search_start;
1476                         max_hole_size = hole_size;
1477                 }
1478         }
1479
1480         /* See above. */
1481         if (max_hole_size < num_bytes)
1482                 ret = -ENOSPC;
1483         else
1484                 ret = 0;
1485
1486 out:
1487         btrfs_free_path(path);
1488         *start = max_hole_start;
1489         if (len)
1490                 *len = max_hole_size;
1491         return ret;
1492 }
1493
1494 int find_free_dev_extent(struct btrfs_trans_handle *trans,
1495                          struct btrfs_device *device, u64 num_bytes,
1496                          u64 *start, u64 *len)
1497 {
1498         /* FIXME use last free of some kind */
1499         return find_free_dev_extent_start(trans->transaction, device,
1500                                           num_bytes, 0, start, len);
1501 }
1502
1503 static int btrfs_free_dev_extent(struct btrfs_trans_handle *trans,
1504                           struct btrfs_device *device,
1505                           u64 start, u64 *dev_extent_len)
1506 {
1507         struct btrfs_fs_info *fs_info = device->fs_info;
1508         struct btrfs_root *root = fs_info->dev_root;
1509         int ret;
1510         struct btrfs_path *path;
1511         struct btrfs_key key;
1512         struct btrfs_key found_key;
1513         struct extent_buffer *leaf = NULL;
1514         struct btrfs_dev_extent *extent = NULL;
1515
1516         path = btrfs_alloc_path();
1517         if (!path)
1518                 return -ENOMEM;
1519
1520         key.objectid = device->devid;
1521         key.offset = start;
1522         key.type = BTRFS_DEV_EXTENT_KEY;
1523 again:
1524         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1525         if (ret > 0) {
1526                 ret = btrfs_previous_item(root, path, key.objectid,
1527                                           BTRFS_DEV_EXTENT_KEY);
1528                 if (ret)
1529                         goto out;
1530                 leaf = path->nodes[0];
1531                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1532                 extent = btrfs_item_ptr(leaf, path->slots[0],
1533                                         struct btrfs_dev_extent);
1534                 BUG_ON(found_key.offset > start || found_key.offset +
1535                        btrfs_dev_extent_length(leaf, extent) < start);
1536                 key = found_key;
1537                 btrfs_release_path(path);
1538                 goto again;
1539         } else if (ret == 0) {
1540                 leaf = path->nodes[0];
1541                 extent = btrfs_item_ptr(leaf, path->slots[0],
1542                                         struct btrfs_dev_extent);
1543         } else {
1544                 btrfs_handle_fs_error(fs_info, ret, "Slot search failed");
1545                 goto out;
1546         }
1547
1548         *dev_extent_len = btrfs_dev_extent_length(leaf, extent);
1549
1550         ret = btrfs_del_item(trans, root, path);
1551         if (ret) {
1552                 btrfs_handle_fs_error(fs_info, ret,
1553                                       "Failed to remove dev extent item");
1554         } else {
1555                 set_bit(BTRFS_TRANS_HAVE_FREE_BGS, &trans->transaction->flags);
1556         }
1557 out:
1558         btrfs_free_path(path);
1559         return ret;
1560 }
1561
1562 static int btrfs_alloc_dev_extent(struct btrfs_trans_handle *trans,
1563                                   struct btrfs_device *device,
1564                                   u64 chunk_offset, u64 start, u64 num_bytes)
1565 {
1566         int ret;
1567         struct btrfs_path *path;
1568         struct btrfs_fs_info *fs_info = device->fs_info;
1569         struct btrfs_root *root = fs_info->dev_root;
1570         struct btrfs_dev_extent *extent;
1571         struct extent_buffer *leaf;
1572         struct btrfs_key key;
1573
1574         WARN_ON(!device->in_fs_metadata);
1575         WARN_ON(device->is_tgtdev_for_dev_replace);
1576         path = btrfs_alloc_path();
1577         if (!path)
1578                 return -ENOMEM;
1579
1580         key.objectid = device->devid;
1581         key.offset = start;
1582         key.type = BTRFS_DEV_EXTENT_KEY;
1583         ret = btrfs_insert_empty_item(trans, root, path, &key,
1584                                       sizeof(*extent));
1585         if (ret)
1586                 goto out;
1587
1588         leaf = path->nodes[0];
1589         extent = btrfs_item_ptr(leaf, path->slots[0],
1590                                 struct btrfs_dev_extent);
1591         btrfs_set_dev_extent_chunk_tree(leaf, extent,
1592                                         BTRFS_CHUNK_TREE_OBJECTID);
1593         btrfs_set_dev_extent_chunk_objectid(leaf, extent,
1594                                             BTRFS_FIRST_CHUNK_TREE_OBJECTID);
1595         btrfs_set_dev_extent_chunk_offset(leaf, extent, chunk_offset);
1596
1597         btrfs_set_dev_extent_length(leaf, extent, num_bytes);
1598         btrfs_mark_buffer_dirty(leaf);
1599 out:
1600         btrfs_free_path(path);
1601         return ret;
1602 }
1603
1604 static u64 find_next_chunk(struct btrfs_fs_info *fs_info)
1605 {
1606         struct extent_map_tree *em_tree;
1607         struct extent_map *em;
1608         struct rb_node *n;
1609         u64 ret = 0;
1610
1611         em_tree = &fs_info->mapping_tree.map_tree;
1612         read_lock(&em_tree->lock);
1613         n = rb_last(&em_tree->map);
1614         if (n) {
1615                 em = rb_entry(n, struct extent_map, rb_node);
1616                 ret = em->start + em->len;
1617         }
1618         read_unlock(&em_tree->lock);
1619
1620         return ret;
1621 }
1622
1623 static noinline int find_next_devid(struct btrfs_fs_info *fs_info,
1624                                     u64 *devid_ret)
1625 {
1626         int ret;
1627         struct btrfs_key key;
1628         struct btrfs_key found_key;
1629         struct btrfs_path *path;
1630
1631         path = btrfs_alloc_path();
1632         if (!path)
1633                 return -ENOMEM;
1634
1635         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1636         key.type = BTRFS_DEV_ITEM_KEY;
1637         key.offset = (u64)-1;
1638
1639         ret = btrfs_search_slot(NULL, fs_info->chunk_root, &key, path, 0, 0);
1640         if (ret < 0)
1641                 goto error;
1642
1643         BUG_ON(ret == 0); /* Corruption */
1644
1645         ret = btrfs_previous_item(fs_info->chunk_root, path,
1646                                   BTRFS_DEV_ITEMS_OBJECTID,
1647                                   BTRFS_DEV_ITEM_KEY);
1648         if (ret) {
1649                 *devid_ret = 1;
1650         } else {
1651                 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
1652                                       path->slots[0]);
1653                 *devid_ret = found_key.offset + 1;
1654         }
1655         ret = 0;
1656 error:
1657         btrfs_free_path(path);
1658         return ret;
1659 }
1660
1661 /*
1662  * the device information is stored in the chunk root
1663  * the btrfs_device struct should be fully filled in
1664  */
1665 static int btrfs_add_device(struct btrfs_trans_handle *trans,
1666                             struct btrfs_fs_info *fs_info,
1667                             struct btrfs_device *device)
1668 {
1669         struct btrfs_root *root = fs_info->chunk_root;
1670         int ret;
1671         struct btrfs_path *path;
1672         struct btrfs_dev_item *dev_item;
1673         struct extent_buffer *leaf;
1674         struct btrfs_key key;
1675         unsigned long ptr;
1676
1677         path = btrfs_alloc_path();
1678         if (!path)
1679                 return -ENOMEM;
1680
1681         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1682         key.type = BTRFS_DEV_ITEM_KEY;
1683         key.offset = device->devid;
1684
1685         ret = btrfs_insert_empty_item(trans, root, path, &key,
1686                                       sizeof(*dev_item));
1687         if (ret)
1688                 goto out;
1689
1690         leaf = path->nodes[0];
1691         dev_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dev_item);
1692
1693         btrfs_set_device_id(leaf, dev_item, device->devid);
1694         btrfs_set_device_generation(leaf, dev_item, 0);
1695         btrfs_set_device_type(leaf, dev_item, device->type);
1696         btrfs_set_device_io_align(leaf, dev_item, device->io_align);
1697         btrfs_set_device_io_width(leaf, dev_item, device->io_width);
1698         btrfs_set_device_sector_size(leaf, dev_item, device->sector_size);
1699         btrfs_set_device_total_bytes(leaf, dev_item,
1700                                      btrfs_device_get_disk_total_bytes(device));
1701         btrfs_set_device_bytes_used(leaf, dev_item,
1702                                     btrfs_device_get_bytes_used(device));
1703         btrfs_set_device_group(leaf, dev_item, 0);
1704         btrfs_set_device_seek_speed(leaf, dev_item, 0);
1705         btrfs_set_device_bandwidth(leaf, dev_item, 0);
1706         btrfs_set_device_start_offset(leaf, dev_item, 0);
1707
1708         ptr = btrfs_device_uuid(dev_item);
1709         write_extent_buffer(leaf, device->uuid, ptr, BTRFS_UUID_SIZE);
1710         ptr = btrfs_device_fsid(dev_item);
1711         write_extent_buffer(leaf, fs_info->fsid, ptr, BTRFS_FSID_SIZE);
1712         btrfs_mark_buffer_dirty(leaf);
1713
1714         ret = 0;
1715 out:
1716         btrfs_free_path(path);
1717         return ret;
1718 }
1719
1720 /*
1721  * Function to update ctime/mtime for a given device path.
1722  * Mainly used for ctime/mtime based probe like libblkid.
1723  */
1724 static void update_dev_time(const char *path_name)
1725 {
1726         struct file *filp;
1727
1728         filp = filp_open(path_name, O_RDWR, 0);
1729         if (IS_ERR(filp))
1730                 return;
1731         file_update_time(filp);
1732         filp_close(filp, NULL);
1733 }
1734
1735 static int btrfs_rm_dev_item(struct btrfs_fs_info *fs_info,
1736                              struct btrfs_device *device)
1737 {
1738         struct btrfs_root *root = fs_info->chunk_root;
1739         int ret;
1740         struct btrfs_path *path;
1741         struct btrfs_key key;
1742         struct btrfs_trans_handle *trans;
1743
1744         path = btrfs_alloc_path();
1745         if (!path)
1746                 return -ENOMEM;
1747
1748         trans = btrfs_start_transaction(root, 0);
1749         if (IS_ERR(trans)) {
1750                 btrfs_free_path(path);
1751                 return PTR_ERR(trans);
1752         }
1753         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1754         key.type = BTRFS_DEV_ITEM_KEY;
1755         key.offset = device->devid;
1756
1757         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1758         if (ret) {
1759                 if (ret > 0)
1760                         ret = -ENOENT;
1761                 btrfs_abort_transaction(trans, ret);
1762                 btrfs_end_transaction(trans);
1763                 goto out;
1764         }
1765
1766         ret = btrfs_del_item(trans, root, path);
1767         if (ret) {
1768                 btrfs_abort_transaction(trans, ret);
1769                 btrfs_end_transaction(trans);
1770         }
1771
1772 out:
1773         btrfs_free_path(path);
1774         if (!ret)
1775                 ret = btrfs_commit_transaction(trans);
1776         return ret;
1777 }
1778
1779 /*
1780  * Verify that @num_devices satisfies the RAID profile constraints in the whole
1781  * filesystem. It's up to the caller to adjust that number regarding eg. device
1782  * replace.
1783  */
1784 static int btrfs_check_raid_min_devices(struct btrfs_fs_info *fs_info,
1785                 u64 num_devices)
1786 {
1787         u64 all_avail;
1788         unsigned seq;
1789         int i;
1790
1791         do {
1792                 seq = read_seqbegin(&fs_info->profiles_lock);
1793
1794                 all_avail = fs_info->avail_data_alloc_bits |
1795                             fs_info->avail_system_alloc_bits |
1796                             fs_info->avail_metadata_alloc_bits;
1797         } while (read_seqretry(&fs_info->profiles_lock, seq));
1798
1799         for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
1800                 if (!(all_avail & btrfs_raid_group[i]))
1801                         continue;
1802
1803                 if (num_devices < btrfs_raid_array[i].devs_min) {
1804                         int ret = btrfs_raid_mindev_error[i];
1805
1806                         if (ret)
1807                                 return ret;
1808                 }
1809         }
1810
1811         return 0;
1812 }
1813
1814 static struct btrfs_device * btrfs_find_next_active_device(
1815                 struct btrfs_fs_devices *fs_devs, struct btrfs_device *device)
1816 {
1817         struct btrfs_device *next_device;
1818
1819         list_for_each_entry(next_device, &fs_devs->devices, dev_list) {
1820                 if (next_device != device &&
1821                         !next_device->missing && next_device->bdev)
1822                         return next_device;
1823         }
1824
1825         return NULL;
1826 }
1827
1828 /*
1829  * Helper function to check if the given device is part of s_bdev / latest_bdev
1830  * and replace it with the provided or the next active device, in the context
1831  * where this function called, there should be always be another device (or
1832  * this_dev) which is active.
1833  */
1834 void btrfs_assign_next_active_device(struct btrfs_fs_info *fs_info,
1835                 struct btrfs_device *device, struct btrfs_device *this_dev)
1836 {
1837         struct btrfs_device *next_device;
1838
1839         if (this_dev)
1840                 next_device = this_dev;
1841         else
1842                 next_device = btrfs_find_next_active_device(fs_info->fs_devices,
1843                                                                 device);
1844         ASSERT(next_device);
1845
1846         if (fs_info->sb->s_bdev &&
1847                         (fs_info->sb->s_bdev == device->bdev))
1848                 fs_info->sb->s_bdev = next_device->bdev;
1849
1850         if (fs_info->fs_devices->latest_bdev == device->bdev)
1851                 fs_info->fs_devices->latest_bdev = next_device->bdev;
1852 }
1853
1854 int btrfs_rm_device(struct btrfs_fs_info *fs_info, const char *device_path,
1855                 u64 devid)
1856 {
1857         struct btrfs_device *device;
1858         struct btrfs_fs_devices *cur_devices;
1859         u64 num_devices;
1860         int ret = 0;
1861
1862         mutex_lock(&uuid_mutex);
1863
1864         num_devices = fs_info->fs_devices->num_devices;
1865         btrfs_dev_replace_lock(&fs_info->dev_replace, 0);
1866         if (btrfs_dev_replace_is_ongoing(&fs_info->dev_replace)) {
1867                 WARN_ON(num_devices < 1);
1868                 num_devices--;
1869         }
1870         btrfs_dev_replace_unlock(&fs_info->dev_replace, 0);
1871
1872         ret = btrfs_check_raid_min_devices(fs_info, num_devices - 1);
1873         if (ret)
1874                 goto out;
1875
1876         ret = btrfs_find_device_by_devspec(fs_info, devid, device_path,
1877                                            &device);
1878         if (ret)
1879                 goto out;
1880
1881         if (device->is_tgtdev_for_dev_replace) {
1882                 ret = BTRFS_ERROR_DEV_TGT_REPLACE;
1883                 goto out;
1884         }
1885
1886         if (device->writeable && fs_info->fs_devices->rw_devices == 1) {
1887                 ret = BTRFS_ERROR_DEV_ONLY_WRITABLE;
1888                 goto out;
1889         }
1890
1891         if (device->writeable) {
1892                 mutex_lock(&fs_info->chunk_mutex);
1893                 list_del_init(&device->dev_alloc_list);
1894                 device->fs_devices->rw_devices--;
1895                 mutex_unlock(&fs_info->chunk_mutex);
1896         }
1897
1898         mutex_unlock(&uuid_mutex);
1899         ret = btrfs_shrink_device(device, 0);
1900         mutex_lock(&uuid_mutex);
1901         if (ret)
1902                 goto error_undo;
1903
1904         /*
1905          * TODO: the superblock still includes this device in its num_devices
1906          * counter although write_all_supers() is not locked out. This
1907          * could give a filesystem state which requires a degraded mount.
1908          */
1909         ret = btrfs_rm_dev_item(fs_info, device);
1910         if (ret)
1911                 goto error_undo;
1912
1913         device->in_fs_metadata = 0;
1914         btrfs_scrub_cancel_dev(fs_info, device);
1915
1916         /*
1917          * the device list mutex makes sure that we don't change
1918          * the device list while someone else is writing out all
1919          * the device supers. Whoever is writing all supers, should
1920          * lock the device list mutex before getting the number of
1921          * devices in the super block (super_copy). Conversely,
1922          * whoever updates the number of devices in the super block
1923          * (super_copy) should hold the device list mutex.
1924          */
1925
1926         cur_devices = device->fs_devices;
1927         mutex_lock(&fs_info->fs_devices->device_list_mutex);
1928         list_del_rcu(&device->dev_list);
1929
1930         device->fs_devices->num_devices--;
1931         device->fs_devices->total_devices--;
1932
1933         if (device->missing)
1934                 device->fs_devices->missing_devices--;
1935
1936         btrfs_assign_next_active_device(fs_info, device, NULL);
1937
1938         if (device->bdev) {
1939                 device->fs_devices->open_devices--;
1940                 /* remove sysfs entry */
1941                 btrfs_sysfs_rm_device_link(fs_info->fs_devices, device);
1942         }
1943
1944         num_devices = btrfs_super_num_devices(fs_info->super_copy) - 1;
1945         btrfs_set_super_num_devices(fs_info->super_copy, num_devices);
1946         mutex_unlock(&fs_info->fs_devices->device_list_mutex);
1947
1948         /*
1949          * at this point, the device is zero sized and detached from
1950          * the devices list.  All that's left is to zero out the old
1951          * supers and free the device.
1952          */
1953         if (device->writeable)
1954                 btrfs_scratch_superblocks(device->bdev, device->name->str);
1955
1956         btrfs_close_bdev(device);
1957         call_rcu(&device->rcu, free_device);
1958
1959         if (cur_devices->open_devices == 0) {
1960                 struct btrfs_fs_devices *fs_devices;
1961                 fs_devices = fs_info->fs_devices;
1962                 while (fs_devices) {
1963                         if (fs_devices->seed == cur_devices) {
1964                                 fs_devices->seed = cur_devices->seed;
1965                                 break;
1966                         }
1967                         fs_devices = fs_devices->seed;
1968                 }
1969                 cur_devices->seed = NULL;
1970                 __btrfs_close_devices(cur_devices);
1971                 free_fs_devices(cur_devices);
1972         }
1973
1974 out:
1975         mutex_unlock(&uuid_mutex);
1976         return ret;
1977
1978 error_undo:
1979         if (device->writeable) {
1980                 mutex_lock(&fs_info->chunk_mutex);
1981                 list_add(&device->dev_alloc_list,
1982                          &fs_info->fs_devices->alloc_list);
1983                 device->fs_devices->rw_devices++;
1984                 mutex_unlock(&fs_info->chunk_mutex);
1985         }
1986         goto out;
1987 }
1988
1989 void btrfs_rm_dev_replace_remove_srcdev(struct btrfs_fs_info *fs_info,
1990                                         struct btrfs_device *srcdev)
1991 {
1992         struct btrfs_fs_devices *fs_devices;
1993
1994         WARN_ON(!mutex_is_locked(&fs_info->fs_devices->device_list_mutex));
1995
1996         /*
1997          * in case of fs with no seed, srcdev->fs_devices will point
1998          * to fs_devices of fs_info. However when the dev being replaced is
1999          * a seed dev it will point to the seed's local fs_devices. In short
2000          * srcdev will have its correct fs_devices in both the cases.
2001          */
2002         fs_devices = srcdev->fs_devices;
2003
2004         list_del_rcu(&srcdev->dev_list);
2005         list_del(&srcdev->dev_alloc_list);
2006         fs_devices->num_devices--;
2007         if (srcdev->missing)
2008                 fs_devices->missing_devices--;
2009
2010         if (srcdev->writeable)
2011                 fs_devices->rw_devices--;
2012
2013         if (srcdev->bdev)
2014                 fs_devices->open_devices--;
2015 }
2016
2017 void btrfs_rm_dev_replace_free_srcdev(struct btrfs_fs_info *fs_info,
2018                                       struct btrfs_device *srcdev)
2019 {
2020         struct btrfs_fs_devices *fs_devices = srcdev->fs_devices;
2021
2022         if (srcdev->writeable) {
2023                 /* zero out the old super if it is writable */
2024                 btrfs_scratch_superblocks(srcdev->bdev, srcdev->name->str);
2025         }
2026
2027         btrfs_close_bdev(srcdev);
2028         call_rcu(&srcdev->rcu, free_device);
2029
2030         /* if this is no devs we rather delete the fs_devices */
2031         if (!fs_devices->num_devices) {
2032                 struct btrfs_fs_devices *tmp_fs_devices;
2033
2034                 /*
2035                  * On a mounted FS, num_devices can't be zero unless it's a
2036                  * seed. In case of a seed device being replaced, the replace
2037                  * target added to the sprout FS, so there will be no more
2038                  * device left under the seed FS.
2039                  */
2040                 ASSERT(fs_devices->seeding);
2041
2042                 tmp_fs_devices = fs_info->fs_devices;
2043                 while (tmp_fs_devices) {
2044                         if (tmp_fs_devices->seed == fs_devices) {
2045                                 tmp_fs_devices->seed = fs_devices->seed;
2046                                 break;
2047                         }
2048                         tmp_fs_devices = tmp_fs_devices->seed;
2049                 }
2050                 fs_devices->seed = NULL;
2051                 __btrfs_close_devices(fs_devices);
2052                 free_fs_devices(fs_devices);
2053         }
2054 }
2055
2056 void btrfs_destroy_dev_replace_tgtdev(struct btrfs_fs_info *fs_info,
2057                                       struct btrfs_device *tgtdev)
2058 {
2059         mutex_lock(&uuid_mutex);
2060         WARN_ON(!tgtdev);
2061         mutex_lock(&fs_info->fs_devices->device_list_mutex);
2062
2063         btrfs_sysfs_rm_device_link(fs_info->fs_devices, tgtdev);
2064
2065         if (tgtdev->bdev)
2066                 fs_info->fs_devices->open_devices--;
2067
2068         fs_info->fs_devices->num_devices--;
2069
2070         btrfs_assign_next_active_device(fs_info, tgtdev, NULL);
2071
2072         list_del_rcu(&tgtdev->dev_list);
2073
2074         mutex_unlock(&fs_info->fs_devices->device_list_mutex);
2075         mutex_unlock(&uuid_mutex);
2076
2077         /*
2078          * The update_dev_time() with in btrfs_scratch_superblocks()
2079          * may lead to a call to btrfs_show_devname() which will try
2080          * to hold device_list_mutex. And here this device
2081          * is already out of device list, so we don't have to hold
2082          * the device_list_mutex lock.
2083          */
2084         btrfs_scratch_superblocks(tgtdev->bdev, tgtdev->name->str);
2085
2086         btrfs_close_bdev(tgtdev);
2087         call_rcu(&tgtdev->rcu, free_device);
2088 }
2089
2090 static int btrfs_find_device_by_path(struct btrfs_fs_info *fs_info,
2091                                      const char *device_path,
2092                                      struct btrfs_device **device)
2093 {
2094         int ret = 0;
2095         struct btrfs_super_block *disk_super;
2096         u64 devid;
2097         u8 *dev_uuid;
2098         struct block_device *bdev;
2099         struct buffer_head *bh;
2100
2101         *device = NULL;
2102         ret = btrfs_get_bdev_and_sb(device_path, FMODE_READ,
2103                                     fs_info->bdev_holder, 0, &bdev, &bh);
2104         if (ret)
2105                 return ret;
2106         disk_super = (struct btrfs_super_block *)bh->b_data;
2107         devid = btrfs_stack_device_id(&disk_super->dev_item);
2108         dev_uuid = disk_super->dev_item.uuid;
2109         *device = btrfs_find_device(fs_info, devid, dev_uuid, disk_super->fsid);
2110         brelse(bh);
2111         if (!*device)
2112                 ret = -ENOENT;
2113         blkdev_put(bdev, FMODE_READ);
2114         return ret;
2115 }
2116
2117 int btrfs_find_device_missing_or_by_path(struct btrfs_fs_info *fs_info,
2118                                          const char *device_path,
2119                                          struct btrfs_device **device)
2120 {
2121         *device = NULL;
2122         if (strcmp(device_path, "missing") == 0) {
2123                 struct list_head *devices;
2124                 struct btrfs_device *tmp;
2125
2126                 devices = &fs_info->fs_devices->devices;
2127                 /*
2128                  * It is safe to read the devices since the volume_mutex
2129                  * is held by the caller.
2130                  */
2131                 list_for_each_entry(tmp, devices, dev_list) {
2132                         if (tmp->in_fs_metadata && !tmp->bdev) {
2133                                 *device = tmp;
2134                                 break;
2135                         }
2136                 }
2137
2138                 if (!*device)
2139                         return BTRFS_ERROR_DEV_MISSING_NOT_FOUND;
2140
2141                 return 0;
2142         } else {
2143                 return btrfs_find_device_by_path(fs_info, device_path, device);
2144         }
2145 }
2146
2147 /*
2148  * Lookup a device given by device id, or the path if the id is 0.
2149  */
2150 int btrfs_find_device_by_devspec(struct btrfs_fs_info *fs_info, u64 devid,
2151                                  const char *devpath,
2152                                  struct btrfs_device **device)
2153 {
2154         int ret;
2155
2156         if (devid) {
2157                 ret = 0;
2158                 *device = btrfs_find_device(fs_info, devid, NULL, NULL);
2159                 if (!*device)
2160                         ret = -ENOENT;
2161         } else {
2162                 if (!devpath || !devpath[0])
2163                         return -EINVAL;
2164
2165                 ret = btrfs_find_device_missing_or_by_path(fs_info, devpath,
2166                                                            device);
2167         }
2168         return ret;
2169 }
2170
2171 /*
2172  * does all the dirty work required for changing file system's UUID.
2173  */
2174 static int btrfs_prepare_sprout(struct btrfs_fs_info *fs_info)
2175 {
2176         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
2177         struct btrfs_fs_devices *old_devices;
2178         struct btrfs_fs_devices *seed_devices;
2179         struct btrfs_super_block *disk_super = fs_info->super_copy;
2180         struct btrfs_device *device;
2181         u64 super_flags;
2182
2183         BUG_ON(!mutex_is_locked(&uuid_mutex));
2184         if (!fs_devices->seeding)
2185                 return -EINVAL;
2186
2187         seed_devices = alloc_fs_devices(NULL);
2188         if (IS_ERR(seed_devices))
2189                 return PTR_ERR(seed_devices);
2190
2191         old_devices = clone_fs_devices(fs_devices);
2192         if (IS_ERR(old_devices)) {
2193                 kfree(seed_devices);
2194                 return PTR_ERR(old_devices);
2195         }
2196
2197         list_add(&old_devices->list, &fs_uuids);
2198
2199         memcpy(seed_devices, fs_devices, sizeof(*seed_devices));
2200         seed_devices->opened = 1;
2201         INIT_LIST_HEAD(&seed_devices->devices);
2202         INIT_LIST_HEAD(&seed_devices->alloc_list);
2203         mutex_init(&seed_devices->device_list_mutex);
2204
2205         mutex_lock(&fs_info->fs_devices->device_list_mutex);
2206         list_splice_init_rcu(&fs_devices->devices, &seed_devices->devices,
2207                               synchronize_rcu);
2208         list_for_each_entry(device, &seed_devices->devices, dev_list)
2209                 device->fs_devices = seed_devices;
2210
2211         mutex_lock(&fs_info->chunk_mutex);
2212         list_splice_init(&fs_devices->alloc_list, &seed_devices->alloc_list);
2213         mutex_unlock(&fs_info->chunk_mutex);
2214
2215         fs_devices->seeding = 0;
2216         fs_devices->num_devices = 0;
2217         fs_devices->open_devices = 0;
2218         fs_devices->missing_devices = 0;
2219         fs_devices->rotating = 0;
2220         fs_devices->seed = seed_devices;
2221
2222         generate_random_uuid(fs_devices->fsid);
2223         memcpy(fs_info->fsid, fs_devices->fsid, BTRFS_FSID_SIZE);
2224         memcpy(disk_super->fsid, fs_devices->fsid, BTRFS_FSID_SIZE);
2225         mutex_unlock(&fs_info->fs_devices->device_list_mutex);
2226
2227         super_flags = btrfs_super_flags(disk_super) &
2228                       ~BTRFS_SUPER_FLAG_SEEDING;
2229         btrfs_set_super_flags(disk_super, super_flags);
2230
2231         return 0;
2232 }
2233
2234 /*
2235  * Store the expected generation for seed devices in device items.
2236  */
2237 static int btrfs_finish_sprout(struct btrfs_trans_handle *trans,
2238                                struct btrfs_fs_info *fs_info)
2239 {
2240         struct btrfs_root *root = fs_info->chunk_root;
2241         struct btrfs_path *path;
2242         struct extent_buffer *leaf;
2243         struct btrfs_dev_item *dev_item;
2244         struct btrfs_device *device;
2245         struct btrfs_key key;
2246         u8 fs_uuid[BTRFS_FSID_SIZE];
2247         u8 dev_uuid[BTRFS_UUID_SIZE];
2248         u64 devid;
2249         int ret;
2250
2251         path = btrfs_alloc_path();
2252         if (!path)
2253                 return -ENOMEM;
2254
2255         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
2256         key.offset = 0;
2257         key.type = BTRFS_DEV_ITEM_KEY;
2258
2259         while (1) {
2260                 ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
2261                 if (ret < 0)
2262                         goto error;
2263
2264                 leaf = path->nodes[0];
2265 next_slot:
2266                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
2267                         ret = btrfs_next_leaf(root, path);
2268                         if (ret > 0)
2269                                 break;
2270                         if (ret < 0)
2271                                 goto error;
2272                         leaf = path->nodes[0];
2273                         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2274                         btrfs_release_path(path);
2275                         continue;
2276                 }
2277
2278                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2279                 if (key.objectid != BTRFS_DEV_ITEMS_OBJECTID ||
2280                     key.type != BTRFS_DEV_ITEM_KEY)
2281                         break;
2282
2283                 dev_item = btrfs_item_ptr(leaf, path->slots[0],
2284                                           struct btrfs_dev_item);
2285                 devid = btrfs_device_id(leaf, dev_item);
2286                 read_extent_buffer(leaf, dev_uuid, btrfs_device_uuid(dev_item),
2287                                    BTRFS_UUID_SIZE);
2288                 read_extent_buffer(leaf, fs_uuid, btrfs_device_fsid(dev_item),
2289                                    BTRFS_FSID_SIZE);
2290                 device = btrfs_find_device(fs_info, devid, dev_uuid, fs_uuid);
2291                 BUG_ON(!device); /* Logic error */
2292
2293                 if (device->fs_devices->seeding) {
2294                         btrfs_set_device_generation(leaf, dev_item,
2295                                                     device->generation);
2296                         btrfs_mark_buffer_dirty(leaf);
2297                 }
2298
2299                 path->slots[0]++;
2300                 goto next_slot;
2301         }
2302         ret = 0;
2303 error:
2304         btrfs_free_path(path);
2305         return ret;
2306 }
2307
2308 int btrfs_init_new_device(struct btrfs_fs_info *fs_info, const char *device_path)
2309 {
2310         struct btrfs_root *root = fs_info->dev_root;
2311         struct request_queue *q;
2312         struct btrfs_trans_handle *trans;
2313         struct btrfs_device *device;
2314         struct block_device *bdev;
2315         struct list_head *devices;
2316         struct super_block *sb = fs_info->sb;
2317         struct rcu_string *name;
2318         u64 tmp;
2319         int seeding_dev = 0;
2320         int ret = 0;
2321         bool unlocked = false;
2322
2323         if (sb_rdonly(sb) && !fs_info->fs_devices->seeding)
2324                 return -EROFS;
2325
2326         bdev = blkdev_get_by_path(device_path, FMODE_WRITE | FMODE_EXCL,
2327                                   fs_info->bdev_holder);
2328         if (IS_ERR(bdev))
2329                 return PTR_ERR(bdev);
2330
2331         if (fs_info->fs_devices->seeding) {
2332                 seeding_dev = 1;
2333                 down_write(&sb->s_umount);
2334                 mutex_lock(&uuid_mutex);
2335         }
2336
2337         filemap_write_and_wait(bdev->bd_inode->i_mapping);
2338
2339         devices = &fs_info->fs_devices->devices;
2340
2341         mutex_lock(&fs_info->fs_devices->device_list_mutex);
2342         list_for_each_entry(device, devices, dev_list) {
2343                 if (device->bdev == bdev) {
2344                         ret = -EEXIST;
2345                         mutex_unlock(
2346                                 &fs_info->fs_devices->device_list_mutex);
2347                         goto error;
2348                 }
2349         }
2350         mutex_unlock(&fs_info->fs_devices->device_list_mutex);
2351
2352         device = btrfs_alloc_device(fs_info, NULL, NULL);
2353         if (IS_ERR(device)) {
2354                 /* we can safely leave the fs_devices entry around */
2355                 ret = PTR_ERR(device);
2356                 goto error;
2357         }
2358
2359         name = rcu_string_strdup(device_path, GFP_KERNEL);
2360         if (!name) {
2361                 bio_put(device->flush_bio);
2362                 kfree(device);
2363                 ret = -ENOMEM;
2364                 goto error;
2365         }
2366         rcu_assign_pointer(device->name, name);
2367
2368         trans = btrfs_start_transaction(root, 0);
2369         if (IS_ERR(trans)) {
2370                 rcu_string_free(device->name);
2371                 bio_put(device->flush_bio);
2372                 kfree(device);
2373                 ret = PTR_ERR(trans);
2374                 goto error;
2375         }
2376
2377         q = bdev_get_queue(bdev);
2378         if (blk_queue_discard(q))
2379                 device->can_discard = 1;
2380         device->writeable = 1;
2381         device->generation = trans->transid;
2382         device->io_width = fs_info->sectorsize;
2383         device->io_align = fs_info->sectorsize;
2384         device->sector_size = fs_info->sectorsize;
2385         device->total_bytes = round_down(i_size_read(bdev->bd_inode),
2386                                          fs_info->sectorsize);
2387         device->disk_total_bytes = device->total_bytes;
2388         device->commit_total_bytes = device->total_bytes;
2389         device->fs_info = fs_info;
2390         device->bdev = bdev;
2391         device->in_fs_metadata = 1;
2392         device->is_tgtdev_for_dev_replace = 0;
2393         device->mode = FMODE_EXCL;
2394         device->dev_stats_valid = 1;
2395         set_blocksize(device->bdev, BTRFS_BDEV_BLOCKSIZE);
2396
2397         if (seeding_dev) {
2398                 sb->s_flags &= ~SB_RDONLY;
2399                 ret = btrfs_prepare_sprout(fs_info);
2400                 if (ret) {
2401                         btrfs_abort_transaction(trans, ret);
2402                         goto error_trans;
2403                 }
2404         }
2405
2406         device->fs_devices = fs_info->fs_devices;
2407
2408         mutex_lock(&fs_info->fs_devices->device_list_mutex);
2409         mutex_lock(&fs_info->chunk_mutex);
2410         list_add_rcu(&device->dev_list, &fs_info->fs_devices->devices);
2411         list_add(&device->dev_alloc_list,
2412                  &fs_info->fs_devices->alloc_list);
2413         fs_info->fs_devices->num_devices++;
2414         fs_info->fs_devices->open_devices++;
2415         fs_info->fs_devices->rw_devices++;
2416         fs_info->fs_devices->total_devices++;
2417         fs_info->fs_devices->total_rw_bytes += device->total_bytes;
2418
2419         atomic64_add(device->total_bytes, &fs_info->free_chunk_space);
2420
2421         if (!blk_queue_nonrot(q))
2422                 fs_info->fs_devices->rotating = 1;
2423
2424         tmp = btrfs_super_total_bytes(fs_info->super_copy);
2425         btrfs_set_super_total_bytes(fs_info->super_copy,
2426                 round_down(tmp + device->total_bytes, fs_info->sectorsize));
2427
2428         tmp = btrfs_super_num_devices(fs_info->super_copy);
2429         btrfs_set_super_num_devices(fs_info->super_copy, tmp + 1);
2430
2431         /* add sysfs device entry */
2432         btrfs_sysfs_add_device_link(fs_info->fs_devices, device);
2433
2434         /*
2435          * we've got more storage, clear any full flags on the space
2436          * infos
2437          */
2438         btrfs_clear_space_info_full(fs_info);
2439
2440         mutex_unlock(&fs_info->chunk_mutex);
2441         mutex_unlock(&fs_info->fs_devices->device_list_mutex);
2442
2443         if (seeding_dev) {
2444                 mutex_lock(&fs_info->chunk_mutex);
2445                 ret = init_first_rw_device(trans, fs_info);
2446                 mutex_unlock(&fs_info->chunk_mutex);
2447                 if (ret) {
2448                         btrfs_abort_transaction(trans, ret);
2449                         goto error_sysfs;
2450                 }
2451         }
2452
2453         ret = btrfs_add_device(trans, fs_info, device);
2454         if (ret) {
2455                 btrfs_abort_transaction(trans, ret);
2456                 goto error_sysfs;
2457         }
2458
2459         if (seeding_dev) {
2460                 char fsid_buf[BTRFS_UUID_UNPARSED_SIZE];
2461
2462                 ret = btrfs_finish_sprout(trans, fs_info);
2463                 if (ret) {
2464                         btrfs_abort_transaction(trans, ret);
2465                         goto error_sysfs;
2466                 }
2467
2468                 /* Sprouting would change fsid of the mounted root,
2469                  * so rename the fsid on the sysfs
2470                  */
2471                 snprintf(fsid_buf, BTRFS_UUID_UNPARSED_SIZE, "%pU",
2472                                                 fs_info->fsid);
2473                 if (kobject_rename(&fs_info->fs_devices->fsid_kobj, fsid_buf))
2474                         btrfs_warn(fs_info,
2475                                    "sysfs: failed to create fsid for sprout");
2476         }
2477
2478         ret = btrfs_commit_transaction(trans);
2479
2480         if (seeding_dev) {
2481                 mutex_unlock(&uuid_mutex);
2482                 up_write(&sb->s_umount);
2483                 unlocked = true;
2484
2485                 if (ret) /* transaction commit */
2486                         return ret;
2487
2488                 ret = btrfs_relocate_sys_chunks(fs_info);
2489                 if (ret < 0)
2490                         btrfs_handle_fs_error(fs_info, ret,
2491                                     "Failed to relocate sys chunks after device initialization. This can be fixed using the \"btrfs balance\" command.");
2492                 trans = btrfs_attach_transaction(root);
2493                 if (IS_ERR(trans)) {
2494                         if (PTR_ERR(trans) == -ENOENT)
2495                                 return 0;
2496                         ret = PTR_ERR(trans);
2497                         trans = NULL;
2498                         goto error_sysfs;
2499                 }
2500                 ret = btrfs_commit_transaction(trans);
2501         }
2502
2503         /* Update ctime/mtime for libblkid */
2504         update_dev_time(device_path);
2505         return ret;
2506
2507 error_sysfs:
2508         btrfs_sysfs_rm_device_link(fs_info->fs_devices, device);
2509 error_trans:
2510         if (seeding_dev)
2511                 sb->s_flags |= SB_RDONLY;
2512         if (trans)
2513                 btrfs_end_transaction(trans);
2514         rcu_string_free(device->name);
2515         bio_put(device->flush_bio);
2516         kfree(device);
2517 error:
2518         blkdev_put(bdev, FMODE_EXCL);
2519         if (seeding_dev && !unlocked) {
2520                 mutex_unlock(&uuid_mutex);
2521                 up_write(&sb->s_umount);
2522         }
2523         return ret;
2524 }
2525
2526 int btrfs_init_dev_replace_tgtdev(struct btrfs_fs_info *fs_info,
2527                                   const char *device_path,
2528                                   struct btrfs_device *srcdev,
2529                                   struct btrfs_device **device_out)
2530 {
2531         struct request_queue *q;
2532         struct btrfs_device *device;
2533         struct block_device *bdev;
2534         struct list_head *devices;
2535         struct rcu_string *name;
2536         u64 devid = BTRFS_DEV_REPLACE_DEVID;
2537         int ret = 0;
2538
2539         *device_out = NULL;
2540         if (fs_info->fs_devices->seeding) {
2541                 btrfs_err(fs_info, "the filesystem is a seed filesystem!");
2542                 return -EINVAL;
2543         }
2544
2545         bdev = blkdev_get_by_path(device_path, FMODE_WRITE | FMODE_EXCL,
2546                                   fs_info->bdev_holder);
2547         if (IS_ERR(bdev)) {
2548                 btrfs_err(fs_info, "target device %s is invalid!", device_path);
2549                 return PTR_ERR(bdev);
2550         }
2551
2552         filemap_write_and_wait(bdev->bd_inode->i_mapping);
2553
2554         devices = &fs_info->fs_devices->devices;
2555         list_for_each_entry(device, devices, dev_list) {
2556                 if (device->bdev == bdev) {
2557                         btrfs_err(fs_info,
2558                                   "target device is in the filesystem!");
2559                         ret = -EEXIST;
2560                         goto error;
2561                 }
2562         }
2563
2564
2565         if (i_size_read(bdev->bd_inode) <
2566             btrfs_device_get_total_bytes(srcdev)) {
2567                 btrfs_err(fs_info,
2568                           "target device is smaller than source device!");
2569                 ret = -EINVAL;
2570                 goto error;
2571         }
2572
2573
2574         device = btrfs_alloc_device(NULL, &devid, NULL);
2575         if (IS_ERR(device)) {
2576                 ret = PTR_ERR(device);
2577                 goto error;
2578         }
2579
2580         name = rcu_string_strdup(device_path, GFP_KERNEL);
2581         if (!name) {
2582                 bio_put(device->flush_bio);
2583                 kfree(device);
2584                 ret = -ENOMEM;
2585                 goto error;
2586         }
2587         rcu_assign_pointer(device->name, name);
2588
2589         q = bdev_get_queue(bdev);
2590         if (blk_queue_discard(q))
2591                 device->can_discard = 1;
2592         mutex_lock(&fs_info->fs_devices->device_list_mutex);
2593         device->writeable = 1;
2594         device->generation = 0;
2595         device->io_width = fs_info->sectorsize;
2596         device->io_align = fs_info->sectorsize;
2597         device->sector_size = fs_info->sectorsize;
2598         device->total_bytes = btrfs_device_get_total_bytes(srcdev);
2599         device->disk_total_bytes = btrfs_device_get_disk_total_bytes(srcdev);
2600         device->bytes_used = btrfs_device_get_bytes_used(srcdev);
2601         ASSERT(list_empty(&srcdev->resized_list));
2602         device->commit_total_bytes = srcdev->commit_total_bytes;
2603         device->commit_bytes_used = device->bytes_used;
2604         device->fs_info = fs_info;
2605         device->bdev = bdev;
2606         device->in_fs_metadata = 1;
2607         device->is_tgtdev_for_dev_replace = 1;
2608         device->mode = FMODE_EXCL;
2609         device->dev_stats_valid = 1;
2610         set_blocksize(device->bdev, BTRFS_BDEV_BLOCKSIZE);
2611         device->fs_devices = fs_info->fs_devices;
2612         list_add(&device->dev_list, &fs_info->fs_devices->devices);
2613         fs_info->fs_devices->num_devices++;
2614         fs_info->fs_devices->open_devices++;
2615         mutex_unlock(&fs_info->fs_devices->device_list_mutex);
2616
2617         *device_out = device;
2618         return ret;
2619
2620 error:
2621         blkdev_put(bdev, FMODE_EXCL);
2622         return ret;
2623 }
2624
2625 void btrfs_init_dev_replace_tgtdev_for_resume(struct btrfs_fs_info *fs_info,
2626                                               struct btrfs_device *tgtdev)
2627 {
2628         u32 sectorsize = fs_info->sectorsize;
2629
2630         WARN_ON(fs_info->fs_devices->rw_devices == 0);
2631         tgtdev->io_width = sectorsize;
2632         tgtdev->io_align = sectorsize;
2633         tgtdev->sector_size = sectorsize;
2634         tgtdev->fs_info = fs_info;
2635         tgtdev->in_fs_metadata = 1;
2636 }
2637
2638 static noinline int btrfs_update_device(struct btrfs_trans_handle *trans,
2639                                         struct btrfs_device *device)
2640 {
2641         int ret;
2642         struct btrfs_path *path;
2643         struct btrfs_root *root = device->fs_info->chunk_root;
2644         struct btrfs_dev_item *dev_item;
2645         struct extent_buffer *leaf;
2646         struct btrfs_key key;
2647
2648         path = btrfs_alloc_path();
2649         if (!path)
2650                 return -ENOMEM;
2651
2652         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
2653         key.type = BTRFS_DEV_ITEM_KEY;
2654         key.offset = device->devid;
2655
2656         ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
2657         if (ret < 0)
2658                 goto out;
2659
2660         if (ret > 0) {
2661                 ret = -ENOENT;
2662                 goto out;
2663         }
2664
2665         leaf = path->nodes[0];
2666         dev_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dev_item);
2667
2668         btrfs_set_device_id(leaf, dev_item, device->devid);
2669         btrfs_set_device_type(leaf, dev_item, device->type);
2670         btrfs_set_device_io_align(leaf, dev_item, device->io_align);
2671         btrfs_set_device_io_width(leaf, dev_item, device->io_width);
2672         btrfs_set_device_sector_size(leaf, dev_item, device->sector_size);
2673         btrfs_set_device_total_bytes(leaf, dev_item,
2674                                      btrfs_device_get_disk_total_bytes(device));
2675         btrfs_set_device_bytes_used(leaf, dev_item,
2676                                     btrfs_device_get_bytes_used(device));
2677         btrfs_mark_buffer_dirty(leaf);
2678
2679 out:
2680         btrfs_free_path(path);
2681         return ret;
2682 }
2683
2684 int btrfs_grow_device(struct btrfs_trans_handle *trans,
2685                       struct btrfs_device *device, u64 new_size)
2686 {
2687         struct btrfs_fs_info *fs_info = device->fs_info;
2688         struct btrfs_super_block *super_copy = fs_info->super_copy;
2689         struct btrfs_fs_devices *fs_devices;
2690         u64 old_total;
2691         u64 diff;
2692
2693         if (!device->writeable)
2694                 return -EACCES;
2695
2696         new_size = round_down(new_size, fs_info->sectorsize);
2697
2698         mutex_lock(&fs_info->chunk_mutex);
2699         old_total = btrfs_super_total_bytes(super_copy);
2700         diff = round_down(new_size - device->total_bytes, fs_info->sectorsize);
2701
2702         if (new_size <= device->total_bytes ||
2703             device->is_tgtdev_for_dev_replace) {
2704                 mutex_unlock(&fs_info->chunk_mutex);
2705                 return -EINVAL;
2706         }
2707
2708         fs_devices = fs_info->fs_devices;
2709
2710         btrfs_set_super_total_bytes(super_copy,
2711                         round_down(old_total + diff, fs_info->sectorsize));
2712         device->fs_devices->total_rw_bytes += diff;
2713
2714         btrfs_device_set_total_bytes(device, new_size);
2715         btrfs_device_set_disk_total_bytes(device, new_size);
2716         btrfs_clear_space_info_full(device->fs_info);
2717         if (list_empty(&device->resized_list))
2718                 list_add_tail(&device->resized_list,
2719                               &fs_devices->resized_devices);
2720         mutex_unlock(&fs_info->chunk_mutex);
2721
2722         return btrfs_update_device(trans, device);
2723 }
2724
2725 static int btrfs_free_chunk(struct btrfs_trans_handle *trans,
2726                             struct btrfs_fs_info *fs_info, u64 chunk_offset)
2727 {
2728         struct btrfs_root *root = fs_info->chunk_root;
2729         int ret;
2730         struct btrfs_path *path;
2731         struct btrfs_key key;
2732
2733         path = btrfs_alloc_path();
2734         if (!path)
2735                 return -ENOMEM;
2736
2737         key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
2738         key.offset = chunk_offset;
2739         key.type = BTRFS_CHUNK_ITEM_KEY;
2740
2741         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
2742         if (ret < 0)
2743                 goto out;
2744         else if (ret > 0) { /* Logic error or corruption */
2745                 btrfs_handle_fs_error(fs_info, -ENOENT,
2746                                       "Failed lookup while freeing chunk.");
2747                 ret = -ENOENT;
2748                 goto out;
2749         }
2750
2751         ret = btrfs_del_item(trans, root, path);
2752         if (ret < 0)
2753                 btrfs_handle_fs_error(fs_info, ret,
2754                                       "Failed to delete chunk item.");
2755 out:
2756         btrfs_free_path(path);
2757         return ret;
2758 }
2759
2760 static int btrfs_del_sys_chunk(struct btrfs_fs_info *fs_info, u64 chunk_offset)
2761 {
2762         struct btrfs_super_block *super_copy = fs_info->super_copy;
2763         struct btrfs_disk_key *disk_key;
2764         struct btrfs_chunk *chunk;
2765         u8 *ptr;
2766         int ret = 0;
2767         u32 num_stripes;
2768         u32 array_size;
2769         u32 len = 0;
2770         u32 cur;
2771         struct btrfs_key key;
2772
2773         mutex_lock(&fs_info->chunk_mutex);
2774         array_size = btrfs_super_sys_array_size(super_copy);
2775
2776         ptr = super_copy->sys_chunk_array;
2777         cur = 0;
2778
2779         while (cur < array_size) {
2780                 disk_key = (struct btrfs_disk_key *)ptr;
2781                 btrfs_disk_key_to_cpu(&key, disk_key);
2782
2783                 len = sizeof(*disk_key);
2784
2785                 if (key.type == BTRFS_CHUNK_ITEM_KEY) {
2786                         chunk = (struct btrfs_chunk *)(ptr + len);
2787                         num_stripes = btrfs_stack_chunk_num_stripes(chunk);
2788                         len += btrfs_chunk_item_size(num_stripes);
2789                 } else {
2790                         ret = -EIO;
2791                         break;
2792                 }
2793                 if (key.objectid == BTRFS_FIRST_CHUNK_TREE_OBJECTID &&
2794                     key.offset == chunk_offset) {
2795                         memmove(ptr, ptr + len, array_size - (cur + len));
2796                         array_size -= len;
2797                         btrfs_set_super_sys_array_size(super_copy, array_size);
2798                 } else {
2799                         ptr += len;
2800                         cur += len;
2801                 }
2802         }
2803         mutex_unlock(&fs_info->chunk_mutex);
2804         return ret;
2805 }
2806
2807 static struct extent_map *get_chunk_map(struct btrfs_fs_info *fs_info,
2808                                         u64 logical, u64 length)
2809 {
2810         struct extent_map_tree *em_tree;
2811         struct extent_map *em;
2812
2813         em_tree = &fs_info->mapping_tree.map_tree;
2814         read_lock(&em_tree->lock);
2815         em = lookup_extent_mapping(em_tree, logical, length);
2816         read_unlock(&em_tree->lock);
2817
2818         if (!em) {
2819                 btrfs_crit(fs_info, "unable to find logical %llu length %llu",
2820                            logical, length);
2821                 return ERR_PTR(-EINVAL);
2822         }
2823
2824         if (em->start > logical || em->start + em->len < logical) {
2825                 btrfs_crit(fs_info,
2826                            "found a bad mapping, wanted %llu-%llu, found %llu-%llu",
2827                            logical, length, em->start, em->start + em->len);
2828                 free_extent_map(em);
2829                 return ERR_PTR(-EINVAL);
2830         }
2831
2832         /* callers are responsible for dropping em's ref. */
2833         return em;
2834 }
2835
2836 int btrfs_remove_chunk(struct btrfs_trans_handle *trans,
2837                        struct btrfs_fs_info *fs_info, u64 chunk_offset)
2838 {
2839         struct extent_map *em;
2840         struct map_lookup *map;
2841         u64 dev_extent_len = 0;
2842         int i, ret = 0;
2843         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
2844
2845         em = get_chunk_map(fs_info, chunk_offset, 1);
2846         if (IS_ERR(em)) {
2847                 /*
2848                  * This is a logic error, but we don't want to just rely on the
2849                  * user having built with ASSERT enabled, so if ASSERT doesn't
2850                  * do anything we still error out.
2851                  */
2852                 ASSERT(0);
2853                 return PTR_ERR(em);
2854         }
2855         map = em->map_lookup;
2856         mutex_lock(&fs_info->chunk_mutex);
2857         check_system_chunk(trans, fs_info, map->type);
2858         mutex_unlock(&fs_info->chunk_mutex);
2859
2860         /*
2861          * Take the device list mutex to prevent races with the final phase of
2862          * a device replace operation that replaces the device object associated
2863          * with map stripes (dev-replace.c:btrfs_dev_replace_finishing()).
2864          */
2865         mutex_lock(&fs_devices->device_list_mutex);
2866         for (i = 0; i < map->num_stripes; i++) {
2867                 struct btrfs_device *device = map->stripes[i].dev;
2868                 ret = btrfs_free_dev_extent(trans, device,
2869                                             map->stripes[i].physical,
2870                                             &dev_extent_len);
2871                 if (ret) {
2872                         mutex_unlock(&fs_devices->device_list_mutex);
2873                         btrfs_abort_transaction(trans, ret);
2874                         goto out;
2875                 }
2876
2877                 if (device->bytes_used > 0) {
2878                         mutex_lock(&fs_info->chunk_mutex);
2879                         btrfs_device_set_bytes_used(device,
2880                                         device->bytes_used - dev_extent_len);
2881                         atomic64_add(dev_extent_len, &fs_info->free_chunk_space);
2882                         btrfs_clear_space_info_full(fs_info);
2883                         mutex_unlock(&fs_info->chunk_mutex);
2884                 }
2885
2886                 if (map->stripes[i].dev) {
2887                         ret = btrfs_update_device(trans, map->stripes[i].dev);
2888                         if (ret) {
2889                                 mutex_unlock(&fs_devices->device_list_mutex);
2890                                 btrfs_abort_transaction(trans, ret);
2891                                 goto out;
2892                         }
2893                 }
2894         }
2895         mutex_unlock(&fs_devices->device_list_mutex);
2896
2897         ret = btrfs_free_chunk(trans, fs_info, chunk_offset);
2898         if (ret) {
2899                 btrfs_abort_transaction(trans, ret);
2900                 goto out;
2901         }
2902
2903         trace_btrfs_chunk_free(fs_info, map, chunk_offset, em->len);
2904
2905         if (map->type & BTRFS_BLOCK_GROUP_SYSTEM) {
2906                 ret = btrfs_del_sys_chunk(fs_info, chunk_offset);
2907                 if (ret) {
2908                         btrfs_abort_transaction(trans, ret);
2909                         goto out;
2910                 }
2911         }
2912
2913         ret = btrfs_remove_block_group(trans, fs_info, chunk_offset, em);
2914         if (ret) {
2915                 btrfs_abort_transaction(trans, ret);
2916                 goto out;
2917         }
2918
2919 out:
2920         /* once for us */
2921         free_extent_map(em);
2922         return ret;
2923 }
2924
2925 static int btrfs_relocate_chunk(struct btrfs_fs_info *fs_info, u64 chunk_offset)
2926 {
2927         struct btrfs_root *root = fs_info->chunk_root;
2928         struct btrfs_trans_handle *trans;
2929         int ret;
2930
2931         /*
2932          * Prevent races with automatic removal of unused block groups.
2933          * After we relocate and before we remove the chunk with offset
2934          * chunk_offset, automatic removal of the block group can kick in,
2935          * resulting in a failure when calling btrfs_remove_chunk() below.
2936          *
2937          * Make sure to acquire this mutex before doing a tree search (dev
2938          * or chunk trees) to find chunks. Otherwise the cleaner kthread might
2939          * call btrfs_remove_chunk() (through btrfs_delete_unused_bgs()) after
2940          * we release the path used to search the chunk/dev tree and before
2941          * the current task acquires this mutex and calls us.
2942          */
2943         ASSERT(mutex_is_locked(&fs_info->delete_unused_bgs_mutex));
2944
2945         ret = btrfs_can_relocate(fs_info, chunk_offset);
2946         if (ret)
2947                 return -ENOSPC;
2948
2949         /* step one, relocate all the extents inside this chunk */
2950         btrfs_scrub_pause(fs_info);
2951         ret = btrfs_relocate_block_group(fs_info, chunk_offset);
2952         btrfs_scrub_continue(fs_info);
2953         if (ret)
2954                 return ret;
2955
2956         trans = btrfs_start_trans_remove_block_group(root->fs_info,
2957                                                      chunk_offset);
2958         if (IS_ERR(trans)) {
2959                 ret = PTR_ERR(trans);
2960                 btrfs_handle_fs_error(root->fs_info, ret, NULL);
2961                 return ret;
2962         }
2963
2964         /*
2965          * step two, delete the device extents and the
2966          * chunk tree entries
2967          */
2968         ret = btrfs_remove_chunk(trans, fs_info, chunk_offset);
2969         btrfs_end_transaction(trans);
2970         return ret;
2971 }
2972
2973 static int btrfs_relocate_sys_chunks(struct btrfs_fs_info *fs_info)
2974 {
2975         struct btrfs_root *chunk_root = fs_info->chunk_root;
2976         struct btrfs_path *path;
2977         struct extent_buffer *leaf;
2978         struct btrfs_chunk *chunk;
2979         struct btrfs_key key;
2980         struct btrfs_key found_key;
2981         u64 chunk_type;
2982         bool retried = false;
2983         int failed = 0;
2984         int ret;
2985
2986         path = btrfs_alloc_path();
2987         if (!path)
2988                 return -ENOMEM;
2989
2990 again:
2991         key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
2992         key.offset = (u64)-1;
2993         key.type = BTRFS_CHUNK_ITEM_KEY;
2994
2995         while (1) {
2996                 mutex_lock(&fs_info->delete_unused_bgs_mutex);
2997                 ret = btrfs_search_slot(NULL, chunk_root, &key, path, 0, 0);
2998                 if (ret < 0) {
2999                         mutex_unlock(&fs_info->delete_unused_bgs_mutex);
3000                         goto error;
3001                 }
3002                 BUG_ON(ret == 0); /* Corruption */
3003
3004                 ret = btrfs_previous_item(chunk_root, path, key.objectid,
3005                                           key.type);
3006                 if (ret)
3007                         mutex_unlock(&fs_info->delete_unused_bgs_mutex);
3008                 if (ret < 0)
3009                         goto error;
3010                 if (ret > 0)
3011                         break;
3012
3013                 leaf = path->nodes[0];
3014                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
3015
3016                 chunk = btrfs_item_ptr(leaf, path->slots[0],
3017                                        struct btrfs_chunk);
3018                 chunk_type = btrfs_chunk_type(leaf, chunk);
3019                 btrfs_release_path(path);
3020
3021                 if (chunk_type & BTRFS_BLOCK_GROUP_SYSTEM) {
3022                         ret = btrfs_relocate_chunk(fs_info, found_key.offset);
3023                         if (ret == -ENOSPC)
3024                                 failed++;
3025                         else
3026                                 BUG_ON(ret);
3027                 }
3028                 mutex_unlock(&fs_info->delete_unused_bgs_mutex);
3029
3030                 if (found_key.offset == 0)
3031                         break;
3032                 key.offset = found_key.offset - 1;
3033         }
3034         ret = 0;
3035         if (failed && !retried) {
3036                 failed = 0;
3037                 retried = true;
3038                 goto again;
3039         } else if (WARN_ON(failed && retried)) {
3040                 ret = -ENOSPC;
3041         }
3042 error:
3043         btrfs_free_path(path);
3044         return ret;
3045 }
3046
3047 static int insert_balance_item(struct btrfs_fs_info *fs_info,
3048                                struct btrfs_balance_control *bctl)
3049 {
3050         struct btrfs_root *root = fs_info->tree_root;
3051         struct btrfs_trans_handle *trans;
3052         struct btrfs_balance_item *item;
3053         struct btrfs_disk_balance_args disk_bargs;
3054         struct btrfs_path *path;
3055         struct extent_buffer *leaf;
3056         struct btrfs_key key;
3057         int ret, err;
3058
3059         path = btrfs_alloc_path();
3060         if (!path)
3061                 return -ENOMEM;
3062
3063         trans = btrfs_start_transaction(root, 0);
3064         if (IS_ERR(trans)) {
3065                 btrfs_free_path(path);
3066                 return PTR_ERR(trans);
3067         }
3068
3069         key.objectid = BTRFS_BALANCE_OBJECTID;
3070         key.type = BTRFS_TEMPORARY_ITEM_KEY;
3071         key.offset = 0;
3072
3073         ret = btrfs_insert_empty_item(trans, root, path, &key,
3074                                       sizeof(*item));
3075         if (ret)
3076                 goto out;
3077
3078         leaf = path->nodes[0];
3079         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_balance_item);
3080
3081         memzero_extent_buffer(leaf, (unsigned long)item, sizeof(*item));
3082
3083         btrfs_cpu_balance_args_to_disk(&disk_bargs, &bctl->data);
3084         btrfs_set_balance_data(leaf, item, &disk_bargs);
3085         btrfs_cpu_balance_args_to_disk(&disk_bargs, &bctl->meta);
3086         btrfs_set_balance_meta(leaf, item, &disk_bargs);
3087         btrfs_cpu_balance_args_to_disk(&disk_bargs, &bctl->sys);
3088         btrfs_set_balance_sys(leaf, item, &disk_bargs);
3089
3090         btrfs_set_balance_flags(leaf, item, bctl->flags);
3091
3092         btrfs_mark_buffer_dirty(leaf);
3093 out:
3094         btrfs_free_path(path);
3095         err = btrfs_commit_transaction(trans);
3096         if (err && !ret)
3097                 ret = err;
3098         return ret;
3099 }
3100
3101 static int del_balance_item(struct btrfs_fs_info *fs_info)
3102 {
3103         struct btrfs_root *root = fs_info->tree_root;
3104         struct btrfs_trans_handle *trans;
3105         struct btrfs_path *path;
3106         struct btrfs_key key;
3107         int ret, err;
3108
3109         path = btrfs_alloc_path();
3110         if (!path)
3111                 return -ENOMEM;
3112
3113         trans = btrfs_start_transaction(root, 0);
3114         if (IS_ERR(trans)) {
3115                 btrfs_free_path(path);
3116                 return PTR_ERR(trans);
3117         }
3118
3119         key.objectid = BTRFS_BALANCE_OBJECTID;
3120         key.type = BTRFS_TEMPORARY_ITEM_KEY;
3121         key.offset = 0;
3122
3123         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
3124         if (ret < 0)
3125                 goto out;
3126         if (ret > 0) {
3127                 ret = -ENOENT;
3128                 goto out;
3129         }
3130
3131         ret = btrfs_del_item(trans, root, path);
3132 out:
3133         btrfs_free_path(path);
3134         err = btrfs_commit_transaction(trans);
3135         if (err && !ret)
3136                 ret = err;
3137         return ret;
3138 }
3139
3140 /*
3141  * This is a heuristic used to reduce the number of chunks balanced on
3142  * resume after balance was interrupted.
3143  */
3144 static void update_balance_args(struct btrfs_balance_control *bctl)
3145 {
3146         /*
3147          * Turn on soft mode for chunk types that were being converted.
3148          */
3149         if (bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT)
3150                 bctl->data.flags |= BTRFS_BALANCE_ARGS_SOFT;
3151         if (bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT)
3152                 bctl->sys.flags |= BTRFS_BALANCE_ARGS_SOFT;
3153         if (bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT)
3154                 bctl->meta.flags |= BTRFS_BALANCE_ARGS_SOFT;
3155
3156         /*
3157          * Turn on usage filter if is not already used.  The idea is
3158          * that chunks that we have already balanced should be
3159          * reasonably full.  Don't do it for chunks that are being
3160          * converted - that will keep us from relocating unconverted
3161          * (albeit full) chunks.
3162          */
3163         if (!(bctl->data.flags & BTRFS_BALANCE_ARGS_USAGE) &&
3164             !(bctl->data.flags & BTRFS_BALANCE_ARGS_USAGE_RANGE) &&
3165             !(bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT)) {
3166                 bctl->data.flags |= BTRFS_BALANCE_ARGS_USAGE;
3167                 bctl->data.usage = 90;
3168         }
3169         if (!(bctl->sys.flags & BTRFS_BALANCE_ARGS_USAGE) &&
3170             !(bctl->sys.flags & BTRFS_BALANCE_ARGS_USAGE_RANGE) &&
3171             !(bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT)) {
3172                 bctl->sys.flags |= BTRFS_BALANCE_ARGS_USAGE;
3173                 bctl->sys.usage = 90;
3174         }
3175         if (!(bctl->meta.flags & BTRFS_BALANCE_ARGS_USAGE) &&
3176             !(bctl->meta.flags & BTRFS_BALANCE_ARGS_USAGE_RANGE) &&
3177             !(bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT)) {
3178                 bctl->meta.flags |= BTRFS_BALANCE_ARGS_USAGE;
3179                 bctl->meta.usage = 90;
3180         }
3181 }
3182
3183 /*
3184  * Should be called with both balance and volume mutexes held to
3185  * serialize other volume operations (add_dev/rm_dev/resize) with
3186  * restriper.  Same goes for unset_balance_control.
3187  */
3188 static void set_balance_control(struct btrfs_balance_control *bctl)
3189 {
3190         struct btrfs_fs_info *fs_info = bctl->fs_info;
3191
3192         BUG_ON(fs_info->balance_ctl);
3193
3194         spin_lock(&fs_info->balance_lock);
3195         fs_info->balance_ctl = bctl;
3196         spin_unlock(&fs_info->balance_lock);
3197 }
3198
3199 static void unset_balance_control(struct btrfs_fs_info *fs_info)
3200 {
3201         struct btrfs_balance_control *bctl = fs_info->balance_ctl;
3202
3203         BUG_ON(!fs_info->balance_ctl);
3204
3205         spin_lock(&fs_info->balance_lock);
3206         fs_info->balance_ctl = NULL;
3207         spin_unlock(&fs_info->balance_lock);
3208
3209         kfree(bctl);
3210 }
3211
3212 /*
3213  * Balance filters.  Return 1 if chunk should be filtered out
3214  * (should not be balanced).
3215  */
3216 static int chunk_profiles_filter(u64 chunk_type,
3217                                  struct btrfs_balance_args *bargs)
3218 {
3219         chunk_type = chunk_to_extended(chunk_type) &
3220                                 BTRFS_EXTENDED_PROFILE_MASK;
3221
3222         if (bargs->profiles & chunk_type)
3223                 return 0;
3224
3225         return 1;
3226 }
3227
3228 static int chunk_usage_range_filter(struct btrfs_fs_info *fs_info, u64 chunk_offset,
3229                               struct btrfs_balance_args *bargs)
3230 {
3231         struct btrfs_block_group_cache *cache;
3232         u64 chunk_used;
3233         u64 user_thresh_min;
3234         u64 user_thresh_max;
3235         int ret = 1;
3236
3237         cache = btrfs_lookup_block_group(fs_info, chunk_offset);
3238         chunk_used = btrfs_block_group_used(&cache->item);
3239
3240         if (bargs->usage_min == 0)
3241                 user_thresh_min = 0;
3242         else
3243                 user_thresh_min = div_factor_fine(cache->key.offset,
3244                                         bargs->usage_min);
3245
3246         if (bargs->usage_max == 0)
3247                 user_thresh_max = 1;
3248         else if (bargs->usage_max > 100)
3249                 user_thresh_max = cache->key.offset;
3250         else
3251                 user_thresh_max = div_factor_fine(cache->key.offset,
3252                                         bargs->usage_max);
3253
3254         if (user_thresh_min <= chunk_used && chunk_used < user_thresh_max)
3255                 ret = 0;
3256
3257         btrfs_put_block_group(cache);
3258         return ret;
3259 }
3260
3261 static int chunk_usage_filter(struct btrfs_fs_info *fs_info,
3262                 u64 chunk_offset, struct btrfs_balance_args *bargs)
3263 {
3264         struct btrfs_block_group_cache *cache;
3265         u64 chunk_used, user_thresh;
3266         int ret = 1;
3267
3268         cache = btrfs_lookup_block_group(fs_info, chunk_offset);
3269         chunk_used = btrfs_block_group_used(&cache->item);
3270
3271         if (bargs->usage_min == 0)
3272                 user_thresh = 1;
3273         else if (bargs->usage > 100)
3274                 user_thresh = cache->key.offset;
3275         else
3276                 user_thresh = div_factor_fine(cache->key.offset,
3277                                               bargs->usage);
3278
3279         if (chunk_used < user_thresh)
3280                 ret = 0;
3281
3282         btrfs_put_block_group(cache);
3283         return ret;
3284 }
3285
3286 static int chunk_devid_filter(struct extent_buffer *leaf,
3287                               struct btrfs_chunk *chunk,
3288                               struct btrfs_balance_args *bargs)
3289 {
3290         struct btrfs_stripe *stripe;
3291         int num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
3292         int i;
3293
3294         for (i = 0; i < num_stripes; i++) {
3295                 stripe = btrfs_stripe_nr(chunk, i);
3296                 if (btrfs_stripe_devid(leaf, stripe) == bargs->devid)
3297                         return 0;
3298         }
3299
3300         return 1;
3301 }
3302
3303 /* [pstart, pend) */
3304 static int chunk_drange_filter(struct extent_buffer *leaf,
3305                                struct btrfs_chunk *chunk,
3306                                struct btrfs_balance_args *bargs)
3307 {
3308         struct btrfs_stripe *stripe;
3309         int num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
3310         u64 stripe_offset;
3311         u64 stripe_length;
3312         int factor;
3313         int i;
3314
3315         if (!(bargs->flags & BTRFS_BALANCE_ARGS_DEVID))
3316                 return 0;
3317
3318         if (btrfs_chunk_type(leaf, chunk) & (BTRFS_BLOCK_GROUP_DUP |
3319              BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10)) {
3320                 factor = num_stripes / 2;
3321         } else if (btrfs_chunk_type(leaf, chunk) & BTRFS_BLOCK_GROUP_RAID5) {
3322                 factor = num_stripes - 1;
3323         } else if (btrfs_chunk_type(leaf, chunk) & BTRFS_BLOCK_GROUP_RAID6) {
3324                 factor = num_stripes - 2;
3325         } else {
3326                 factor = num_stripes;
3327         }
3328
3329         for (i = 0; i < num_stripes; i++) {
3330                 stripe = btrfs_stripe_nr(chunk, i);
3331                 if (btrfs_stripe_devid(leaf, stripe) != bargs->devid)
3332                         continue;
3333
3334                 stripe_offset = btrfs_stripe_offset(leaf, stripe);
3335                 stripe_length = btrfs_chunk_length(leaf, chunk);
3336                 stripe_length = div_u64(stripe_length, factor);
3337
3338                 if (stripe_offset < bargs->pend &&
3339                     stripe_offset + stripe_length > bargs->pstart)
3340                         return 0;
3341         }
3342
3343         return 1;
3344 }
3345
3346 /* [vstart, vend) */
3347 static int chunk_vrange_filter(struct extent_buffer *leaf,
3348                                struct btrfs_chunk *chunk,
3349                                u64 chunk_offset,
3350                                struct btrfs_balance_args *bargs)
3351 {
3352         if (chunk_offset < bargs->vend &&
3353             chunk_offset + btrfs_chunk_length(leaf, chunk) > bargs->vstart)
3354                 /* at least part of the chunk is inside this vrange */
3355                 return 0;
3356
3357         return 1;
3358 }
3359
3360 static int chunk_stripes_range_filter(struct extent_buffer *leaf,
3361                                struct btrfs_chunk *chunk,
3362                                struct btrfs_balance_args *bargs)
3363 {
3364         int num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
3365
3366         if (bargs->stripes_min <= num_stripes
3367                         && num_stripes <= bargs->stripes_max)
3368                 return 0;
3369
3370         return 1;
3371 }
3372
3373 static int chunk_soft_convert_filter(u64 chunk_type,
3374                                      struct btrfs_balance_args *bargs)
3375 {
3376         if (!(bargs->flags & BTRFS_BALANCE_ARGS_CONVERT))
3377                 return 0;
3378
3379         chunk_type = chunk_to_extended(chunk_type) &
3380                                 BTRFS_EXTENDED_PROFILE_MASK;
3381
3382         if (bargs->target == chunk_type)
3383                 return 1;
3384
3385         return 0;
3386 }
3387
3388 static int should_balance_chunk(struct btrfs_fs_info *fs_info,
3389                                 struct extent_buffer *leaf,
3390                                 struct btrfs_chunk *chunk, u64 chunk_offset)
3391 {
3392         struct btrfs_balance_control *bctl = fs_info->balance_ctl;
3393         struct btrfs_balance_args *bargs = NULL;
3394         u64 chunk_type = btrfs_chunk_type(leaf, chunk);
3395
3396         /* type filter */
3397         if (!((chunk_type & BTRFS_BLOCK_GROUP_TYPE_MASK) &
3398               (bctl->flags & BTRFS_BALANCE_TYPE_MASK))) {
3399                 return 0;
3400         }
3401
3402         if (chunk_type & BTRFS_BLOCK_GROUP_DATA)
3403                 bargs = &bctl->data;
3404         else if (chunk_type & BTRFS_BLOCK_GROUP_SYSTEM)
3405                 bargs = &bctl->sys;
3406         else if (chunk_type & BTRFS_BLOCK_GROUP_METADATA)
3407                 bargs = &bctl->meta;
3408
3409         /* profiles filter */
3410         if ((bargs->flags & BTRFS_BALANCE_ARGS_PROFILES) &&
3411             chunk_profiles_filter(chunk_type, bargs)) {
3412                 return 0;
3413         }
3414
3415         /* usage filter */
3416         if ((bargs->flags & BTRFS_BALANCE_ARGS_USAGE) &&
3417             chunk_usage_filter(fs_info, chunk_offset, bargs)) {
3418                 return 0;
3419         } else if ((bargs->flags & BTRFS_BALANCE_ARGS_USAGE_RANGE) &&
3420             chunk_usage_range_filter(fs_info, chunk_offset, bargs)) {
3421                 return 0;
3422         }
3423
3424         /* devid filter */
3425         if ((bargs->flags & BTRFS_BALANCE_ARGS_DEVID) &&
3426             chunk_devid_filter(leaf, chunk, bargs)) {
3427                 return 0;
3428         }
3429
3430         /* drange filter, makes sense only with devid filter */
3431         if ((bargs->flags & BTRFS_BALANCE_ARGS_DRANGE) &&
3432             chunk_drange_filter(leaf, chunk, bargs)) {
3433                 return 0;
3434         }
3435
3436         /* vrange filter */
3437         if ((bargs->flags & BTRFS_BALANCE_ARGS_VRANGE) &&
3438             chunk_vrange_filter(leaf, chunk, chunk_offset, bargs)) {
3439                 return 0;
3440         }
3441
3442         /* stripes filter */
3443         if ((bargs->flags & BTRFS_BALANCE_ARGS_STRIPES_RANGE) &&
3444             chunk_stripes_range_filter(leaf, chunk, bargs)) {
3445                 return 0;
3446         }
3447
3448         /* soft profile changing mode */
3449         if ((bargs->flags & BTRFS_BALANCE_ARGS_SOFT) &&
3450             chunk_soft_convert_filter(chunk_type, bargs)) {
3451                 return 0;
3452         }
3453
3454         /*
3455          * limited by count, must be the last filter
3456          */
3457         if ((bargs->flags & BTRFS_BALANCE_ARGS_LIMIT)) {
3458                 if (bargs->limit == 0)
3459                         return 0;
3460                 else
3461                         bargs->limit--;
3462         } else if ((bargs->flags & BTRFS_BALANCE_ARGS_LIMIT_RANGE)) {
3463                 /*
3464                  * Same logic as the 'limit' filter; the minimum cannot be
3465                  * determined here because we do not have the global information
3466                  * about the count of all chunks that satisfy the filters.
3467                  */
3468                 if (bargs->limit_max == 0)
3469                         return 0;
3470                 else
3471                         bargs->limit_max--;
3472         }
3473
3474         return 1;
3475 }
3476
3477 static int __btrfs_balance(struct btrfs_fs_info *fs_info)
3478 {
3479         struct btrfs_balance_control *bctl = fs_info->balance_ctl;
3480         struct btrfs_root *chunk_root = fs_info->chunk_root;
3481         struct btrfs_root *dev_root = fs_info->dev_root;
3482         struct list_head *devices;
3483         struct btrfs_device *device;
3484         u64 old_size;
3485         u64 size_to_free;
3486         u64 chunk_type;
3487         struct btrfs_chunk *chunk;
3488         struct btrfs_path *path = NULL;
3489         struct btrfs_key key;
3490         struct btrfs_key found_key;
3491         struct btrfs_trans_handle *trans;
3492         struct extent_buffer *leaf;
3493         int slot;
3494         int ret;
3495         int enospc_errors = 0;
3496         bool counting = true;
3497         /* The single value limit and min/max limits use the same bytes in the */
3498         u64 limit_data = bctl->data.limit;
3499         u64 limit_meta = bctl->meta.limit;
3500         u64 limit_sys = bctl->sys.limit;
3501         u32 count_data = 0;
3502         u32 count_meta = 0;
3503         u32 count_sys = 0;
3504         int chunk_reserved = 0;
3505         u64 bytes_used = 0;
3506
3507         /* step one make some room on all the devices */
3508         devices = &fs_info->fs_devices->devices;
3509         list_for_each_entry(device, devices, dev_list) {
3510                 old_size = btrfs_device_get_total_bytes(device);
3511                 size_to_free = div_factor(old_size, 1);
3512                 size_to_free = min_t(u64, size_to_free, SZ_1M);
3513                 if (!device->writeable ||
3514                     btrfs_device_get_total_bytes(device) -
3515                     btrfs_device_get_bytes_used(device) > size_to_free ||
3516                     device->is_tgtdev_for_dev_replace)
3517                         continue;
3518
3519                 ret = btrfs_shrink_device(device, old_size - size_to_free);
3520                 if (ret == -ENOSPC)
3521                         break;
3522                 if (ret) {
3523                         /* btrfs_shrink_device never returns ret > 0 */
3524                         WARN_ON(ret > 0);
3525                         goto error;
3526                 }
3527
3528                 trans = btrfs_start_transaction(dev_root, 0);
3529                 if (IS_ERR(trans)) {
3530                         ret = PTR_ERR(trans);
3531                         btrfs_info_in_rcu(fs_info,
3532                  "resize: unable to start transaction after shrinking device %s (error %d), old size %llu, new size %llu",
3533                                           rcu_str_deref(device->name), ret,
3534                                           old_size, old_size - size_to_free);
3535                         goto error;
3536                 }
3537
3538                 ret = btrfs_grow_device(trans, device, old_size);
3539                 if (ret) {
3540                         btrfs_end_transaction(trans);
3541                         /* btrfs_grow_device never returns ret > 0 */
3542                         WARN_ON(ret > 0);
3543                         btrfs_info_in_rcu(fs_info,
3544                  "resize: unable to grow device after shrinking device %s (error %d), old size %llu, new size %llu",
3545                                           rcu_str_deref(device->name), ret,
3546                                           old_size, old_size - size_to_free);
3547                         goto error;
3548                 }
3549
3550                 btrfs_end_transaction(trans);
3551         }
3552
3553         /* step two, relocate all the chunks */
3554         path = btrfs_alloc_path();
3555         if (!path) {
3556                 ret = -ENOMEM;
3557                 goto error;
3558         }
3559
3560         /* zero out stat counters */
3561         spin_lock(&fs_info->balance_lock);
3562         memset(&bctl->stat, 0, sizeof(bctl->stat));
3563         spin_unlock(&fs_info->balance_lock);
3564 again:
3565         if (!counting) {
3566                 /*
3567                  * The single value limit and min/max limits use the same bytes
3568                  * in the
3569                  */
3570                 bctl->data.limit = limit_data;
3571                 bctl->meta.limit = limit_meta;
3572                 bctl->sys.limit = limit_sys;
3573         }
3574         key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
3575         key.offset = (u64)-1;
3576         key.type = BTRFS_CHUNK_ITEM_KEY;
3577
3578         while (1) {
3579                 if ((!counting && atomic_read(&fs_info->balance_pause_req)) ||
3580                     atomic_read(&fs_info->balance_cancel_req)) {
3581                         ret = -ECANCELED;
3582                         goto error;
3583                 }
3584
3585                 mutex_lock(&fs_info->delete_unused_bgs_mutex);
3586                 ret = btrfs_search_slot(NULL, chunk_root, &key, path, 0, 0);
3587                 if (ret < 0) {
3588                         mutex_unlock(&fs_info->delete_unused_bgs_mutex);
3589                         goto error;
3590                 }
3591
3592                 /*
3593                  * this shouldn't happen, it means the last relocate
3594                  * failed
3595                  */
3596                 if (ret == 0)
3597                         BUG(); /* FIXME break ? */
3598
3599                 ret = btrfs_previous_item(chunk_root, path, 0,
3600                                           BTRFS_CHUNK_ITEM_KEY);
3601                 if (ret) {
3602                         mutex_unlock(&fs_info->delete_unused_bgs_mutex);
3603                         ret = 0;
3604                         break;
3605                 }
3606
3607                 leaf = path->nodes[0];
3608                 slot = path->slots[0];
3609                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
3610
3611                 if (found_key.objectid != key.objectid) {
3612                         mutex_unlock(&fs_info->delete_unused_bgs_mutex);
3613                         break;
3614                 }
3615
3616                 chunk = btrfs_item_ptr(leaf, slot, struct btrfs_chunk);
3617                 chunk_type = btrfs_chunk_type(leaf, chunk);
3618
3619                 if (!counting) {
3620                         spin_lock(&fs_info->balance_lock);
3621                         bctl->stat.considered++;
3622                         spin_unlock(&fs_info->balance_lock);
3623                 }
3624
3625                 ret = should_balance_chunk(fs_info, leaf, chunk,
3626                                            found_key.offset);
3627
3628                 btrfs_release_path(path);
3629                 if (!ret) {
3630                         mutex_unlock(&fs_info->delete_unused_bgs_mutex);
3631                         goto loop;
3632                 }
3633
3634                 if (counting) {
3635                         mutex_unlock(&fs_info->delete_unused_bgs_mutex);
3636                         spin_lock(&fs_info->balance_lock);
3637                         bctl->stat.expected++;
3638                         spin_unlock(&fs_info->balance_lock);
3639
3640                         if (chunk_type & BTRFS_BLOCK_GROUP_DATA)
3641                                 count_data++;
3642                         else if (chunk_type & BTRFS_BLOCK_GROUP_SYSTEM)
3643                                 count_sys++;
3644                         else if (chunk_type & BTRFS_BLOCK_GROUP_METADATA)
3645                                 count_meta++;
3646
3647                         goto loop;
3648                 }
3649
3650                 /*
3651                  * Apply limit_min filter, no need to check if the LIMITS
3652                  * filter is used, limit_min is 0 by default
3653                  */
3654                 if (((chunk_type & BTRFS_BLOCK_GROUP_DATA) &&
3655                                         count_data < bctl->data.limit_min)
3656                                 || ((chunk_type & BTRFS_BLOCK_GROUP_METADATA) &&
3657                                         count_meta < bctl->meta.limit_min)
3658                                 || ((chunk_type & BTRFS_BLOCK_GROUP_SYSTEM) &&
3659                                         count_sys < bctl->sys.limit_min)) {
3660                         mutex_unlock(&fs_info->delete_unused_bgs_mutex);
3661                         goto loop;
3662                 }
3663
3664                 ASSERT(fs_info->data_sinfo);
3665                 spin_lock(&fs_info->data_sinfo->lock);
3666                 bytes_used = fs_info->data_sinfo->bytes_used;
3667                 spin_unlock(&fs_info->data_sinfo->lock);
3668
3669                 if ((chunk_type & BTRFS_BLOCK_GROUP_DATA) &&
3670                     !chunk_reserved && !bytes_used) {
3671                         trans = btrfs_start_transaction(chunk_root, 0);
3672                         if (IS_ERR(trans)) {
3673                                 mutex_unlock(&fs_info->delete_unused_bgs_mutex);
3674                                 ret = PTR_ERR(trans);
3675                                 goto error;
3676                         }
3677
3678                         ret = btrfs_force_chunk_alloc(trans, fs_info,
3679                                                       BTRFS_BLOCK_GROUP_DATA);
3680                         btrfs_end_transaction(trans);
3681                         if (ret < 0) {
3682                                 mutex_unlock(&fs_info->delete_unused_bgs_mutex);
3683                                 goto error;
3684                         }
3685                         chunk_reserved = 1;
3686                 }
3687
3688                 ret = btrfs_relocate_chunk(fs_info, found_key.offset);
3689                 mutex_unlock(&fs_info->delete_unused_bgs_mutex);
3690                 if (ret && ret != -ENOSPC)
3691                         goto error;
3692                 if (ret == -ENOSPC) {
3693                         enospc_errors++;
3694                 } else {
3695                         spin_lock(&fs_info->balance_lock);
3696                         bctl->stat.completed++;
3697                         spin_unlock(&fs_info->balance_lock);
3698                 }
3699 loop:
3700                 if (found_key.offset == 0)
3701                         break;
3702                 key.offset = found_key.offset - 1;
3703         }
3704
3705         if (counting) {
3706                 btrfs_release_path(path);
3707                 counting = false;
3708                 goto again;
3709         }
3710 error:
3711         btrfs_free_path(path);
3712         if (enospc_errors) {
3713                 btrfs_info(fs_info, "%d enospc errors during balance",
3714                            enospc_errors);
3715                 if (!ret)
3716                         ret = -ENOSPC;
3717         }
3718
3719         return ret;
3720 }
3721
3722 /**
3723  * alloc_profile_is_valid - see if a given profile is valid and reduced
3724  * @flags: profile to validate
3725  * @extended: if true @flags is treated as an extended profile
3726  */
3727 static int alloc_profile_is_valid(u64 flags, int extended)
3728 {
3729         u64 mask = (extended ? BTRFS_EXTENDED_PROFILE_MASK :
3730                                BTRFS_BLOCK_GROUP_PROFILE_MASK);
3731
3732         flags &= ~BTRFS_BLOCK_GROUP_TYPE_MASK;
3733
3734         /* 1) check that all other bits are zeroed */
3735         if (flags & ~mask)
3736                 return 0;
3737
3738         /* 2) see if profile is reduced */
3739         if (flags == 0)
3740                 return !extended; /* "0" is valid for usual profiles */
3741
3742         /* true if exactly one bit set */
3743         return (flags & (flags - 1)) == 0;
3744 }
3745
3746 static inline int balance_need_close(struct btrfs_fs_info *fs_info)
3747 {
3748         /* cancel requested || normal exit path */
3749         return atomic_read(&fs_info->balance_cancel_req) ||
3750                 (atomic_read(&fs_info->balance_pause_req) == 0 &&
3751                  atomic_read(&fs_info->balance_cancel_req) == 0);
3752 }
3753
3754 static void __cancel_balance(struct btrfs_fs_info *fs_info)
3755 {
3756         int ret;
3757
3758         unset_balance_control(fs_info);
3759         ret = del_balance_item(fs_info);
3760         if (ret)
3761                 btrfs_handle_fs_error(fs_info, ret, NULL);
3762
3763         clear_bit(BTRFS_FS_EXCL_OP, &fs_info->flags);
3764 }
3765
3766 /* Non-zero return value signifies invalidity */
3767 static inline int validate_convert_profile(struct btrfs_balance_args *bctl_arg,
3768                 u64 allowed)
3769 {
3770         return ((bctl_arg->flags & BTRFS_BALANCE_ARGS_CONVERT) &&
3771                 (!alloc_profile_is_valid(bctl_arg->target, 1) ||
3772                  (bctl_arg->target & ~allowed)));
3773 }
3774
3775 /*
3776  * Should be called with both balance and volume mutexes held
3777  */
3778 int btrfs_balance(struct btrfs_balance_control *bctl,
3779                   struct btrfs_ioctl_balance_args *bargs)
3780 {
3781         struct btrfs_fs_info *fs_info = bctl->fs_info;
3782         u64 meta_target, data_target;
3783         u64 allowed;
3784         int mixed = 0;
3785         int ret;
3786         u64 num_devices;
3787         unsigned seq;
3788
3789         if (btrfs_fs_closing(fs_info) ||
3790             atomic_read(&fs_info->balance_pause_req) ||
3791             atomic_read(&fs_info->balance_cancel_req)) {
3792                 ret = -EINVAL;
3793                 goto out;
3794         }
3795
3796         allowed = btrfs_super_incompat_flags(fs_info->super_copy);
3797         if (allowed & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS)
3798                 mixed = 1;
3799
3800         /*
3801          * In case of mixed groups both data and meta should be picked,
3802          * and identical options should be given for both of them.
3803          */
3804         allowed = BTRFS_BALANCE_DATA | BTRFS_BALANCE_METADATA;
3805         if (mixed && (bctl->flags & allowed)) {
3806                 if (!(bctl->flags & BTRFS_BALANCE_DATA) ||
3807                     !(bctl->flags & BTRFS_BALANCE_METADATA) ||
3808                     memcmp(&bctl->data, &bctl->meta, sizeof(bctl->data))) {
3809                         btrfs_err(fs_info,
3810                                   "with mixed groups data and metadata balance options must be the same");
3811                         ret = -EINVAL;
3812                         goto out;
3813                 }
3814         }
3815
3816         num_devices = fs_info->fs_devices->num_devices;
3817         btrfs_dev_replace_lock(&fs_info->dev_replace, 0);
3818         if (btrfs_dev_replace_is_ongoing(&fs_info->dev_replace)) {
3819                 BUG_ON(num_devices < 1);
3820                 num_devices--;
3821         }
3822         btrfs_dev_replace_unlock(&fs_info->dev_replace, 0);
3823         allowed = BTRFS_AVAIL_ALLOC_BIT_SINGLE | BTRFS_BLOCK_GROUP_DUP;
3824         if (num_devices > 1)
3825                 allowed |= (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID1);
3826         if (num_devices > 2)
3827                 allowed |= BTRFS_BLOCK_GROUP_RAID5;
3828         if (num_devices > 3)
3829                 allowed |= (BTRFS_BLOCK_GROUP_RAID10 |
3830                             BTRFS_BLOCK_GROUP_RAID6);
3831         if (validate_convert_profile(&bctl->data, allowed)) {
3832                 btrfs_err(fs_info,
3833                           "unable to start balance with target data profile %llu",
3834                           bctl->data.target);
3835                 ret = -EINVAL;
3836                 goto out;
3837         }
3838         if (validate_convert_profile(&bctl->meta, allowed)) {
3839                 btrfs_err(fs_info,
3840                           "unable to start balance with target metadata profile %llu",
3841                           bctl->meta.target);
3842                 ret = -EINVAL;
3843                 goto out;
3844         }
3845         if (validate_convert_profile(&bctl->sys, allowed)) {
3846                 btrfs_err(fs_info,
3847                           "unable to start balance with target system profile %llu",
3848                           bctl->sys.target);
3849                 ret = -EINVAL;
3850                 goto out;
3851         }
3852
3853         /* allow to reduce meta or sys integrity only if force set */
3854         allowed = BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 |
3855                         BTRFS_BLOCK_GROUP_RAID10 |
3856                         BTRFS_BLOCK_GROUP_RAID5 |
3857                         BTRFS_BLOCK_GROUP_RAID6;
3858         do {
3859                 seq = read_seqbegin(&fs_info->profiles_lock);
3860
3861                 if (((bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
3862                      (fs_info->avail_system_alloc_bits & allowed) &&
3863                      !(bctl->sys.target & allowed)) ||
3864                     ((bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
3865                      (fs_info->avail_metadata_alloc_bits & allowed) &&
3866                      !(bctl->meta.target & allowed))) {
3867                         if (bctl->flags & BTRFS_BALANCE_FORCE) {
3868                                 btrfs_info(fs_info,
3869                                            "force reducing metadata integrity");
3870                         } else {
3871                                 btrfs_err(fs_info,
3872                                           "balance will reduce metadata integrity, use force if you want this");
3873                                 ret = -EINVAL;
3874                                 goto out;
3875                         }
3876                 }
3877         } while (read_seqretry(&fs_info->profiles_lock, seq));
3878
3879         /* if we're not converting, the target field is uninitialized */
3880         meta_target = (bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) ?
3881                 bctl->meta.target : fs_info->avail_metadata_alloc_bits;
3882         data_target = (bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) ?
3883                 bctl->data.target : fs_info->avail_data_alloc_bits;
3884         if (btrfs_get_num_tolerated_disk_barrier_failures(meta_target) <
3885                 btrfs_get_num_tolerated_disk_barrier_failures(data_target)) {
3886                 btrfs_warn(fs_info,
3887                            "metadata profile 0x%llx has lower redundancy than data profile 0x%llx",
3888                            meta_target, data_target);
3889         }
3890
3891         ret = insert_balance_item(fs_info, bctl);
3892         if (ret && ret != -EEXIST)
3893                 goto out;
3894
3895         if (!(bctl->flags & BTRFS_BALANCE_RESUME)) {
3896                 BUG_ON(ret == -EEXIST);
3897                 set_balance_control(bctl);
3898         } else {
3899                 BUG_ON(ret != -EEXIST);
3900                 spin_lock(&fs_info->balance_lock);
3901                 update_balance_args(bctl);
3902                 spin_unlock(&fs_info->balance_lock);
3903         }
3904
3905         atomic_inc(&fs_info->balance_running);
3906         mutex_unlock(&fs_info->balance_mutex);
3907
3908         ret = __btrfs_balance(fs_info);
3909
3910         mutex_lock(&fs_info->balance_mutex);
3911         atomic_dec(&fs_info->balance_running);
3912
3913         if (bargs) {
3914                 memset(bargs, 0, sizeof(*bargs));
3915                 update_ioctl_balance_args(fs_info, 0, bargs);
3916         }
3917
3918         if ((ret && ret != -ECANCELED && ret != -ENOSPC) ||
3919             balance_need_close(fs_info)) {
3920                 __cancel_balance(fs_info);
3921         }
3922
3923         wake_up(&fs_info->balance_wait_q);
3924
3925         return ret;
3926 out:
3927         if (bctl->flags & BTRFS_BALANCE_RESUME)
3928                 __cancel_balance(fs_info);
3929         else {
3930                 kfree(bctl);
3931                 clear_bit(BTRFS_FS_EXCL_OP, &fs_info->flags);
3932         }
3933         return ret;
3934 }
3935
3936 static int balance_kthread(void *data)
3937 {
3938         struct btrfs_fs_info *fs_info = data;
3939         int ret = 0;
3940
3941         mutex_lock(&fs_info->volume_mutex);
3942         mutex_lock(&fs_info->balance_mutex);
3943
3944         if (fs_info->balance_ctl) {
3945                 btrfs_info(fs_info, "continuing balance");
3946                 ret = btrfs_balance(fs_info->balance_ctl, NULL);
3947         }
3948
3949         mutex_unlock(&fs_info->balance_mutex);
3950         mutex_unlock(&fs_info->volume_mutex);
3951
3952         return ret;
3953 }
3954
3955 int btrfs_resume_balance_async(struct btrfs_fs_info *fs_info)
3956 {
3957         struct task_struct *tsk;
3958
3959         spin_lock(&fs_info->balance_lock);
3960         if (!fs_info->balance_ctl) {
3961                 spin_unlock(&fs_info->balance_lock);
3962                 return 0;
3963         }
3964         spin_unlock(&fs_info->balance_lock);
3965
3966         if (btrfs_test_opt(fs_info, SKIP_BALANCE)) {
3967                 btrfs_info(fs_info, "force skipping balance");
3968                 return 0;
3969         }
3970
3971         tsk = kthread_run(balance_kthread, fs_info, "btrfs-balance");
3972         return PTR_ERR_OR_ZERO(tsk);
3973 }
3974
3975 int btrfs_recover_balance(struct btrfs_fs_info *fs_info)
3976 {
3977         struct btrfs_balance_control *bctl;
3978         struct btrfs_balance_item *item;
3979         struct btrfs_disk_balance_args disk_bargs;
3980         struct btrfs_path *path;
3981         struct extent_buffer *leaf;
3982         struct btrfs_key key;
3983         int ret;
3984
3985         path = btrfs_alloc_path();
3986         if (!path)
3987                 return -ENOMEM;
3988
3989         key.objectid = BTRFS_BALANCE_OBJECTID;
3990         key.type = BTRFS_TEMPORARY_ITEM_KEY;
3991         key.offset = 0;
3992
3993         ret = btrfs_search_slot(NULL, fs_info->tree_root, &key, path, 0, 0);
3994         if (ret < 0)
3995                 goto out;
3996         if (ret > 0) { /* ret = -ENOENT; */
3997                 ret = 0;
3998                 goto out;
3999         }
4000
4001         bctl = kzalloc(sizeof(*bctl), GFP_NOFS);
4002         if (!bctl) {
4003                 ret = -ENOMEM;
4004                 goto out;
4005         }
4006
4007         leaf = path->nodes[0];
4008         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_balance_item);
4009
4010         bctl->fs_info = fs_info;
4011         bctl->flags = btrfs_balance_flags(leaf, item);
4012         bctl->flags |= BTRFS_BALANCE_RESUME;
4013
4014         btrfs_balance_data(leaf, item, &disk_bargs);
4015         btrfs_disk_balance_args_to_cpu(&bctl->data, &disk_bargs);
4016         btrfs_balance_meta(leaf, item, &disk_bargs);
4017         btrfs_disk_balance_args_to_cpu(&bctl->meta, &disk_bargs);
4018         btrfs_balance_sys(leaf, item, &disk_bargs);
4019         btrfs_disk_balance_args_to_cpu(&bctl->sys, &disk_bargs);
4020
4021         WARN_ON(test_and_set_bit(BTRFS_FS_EXCL_OP, &fs_info->flags));
4022
4023         mutex_lock(&fs_info->volume_mutex);
4024         mutex_lock(&fs_info->balance_mutex);
4025
4026         set_balance_control(bctl);
4027
4028         mutex_unlock(&fs_info->balance_mutex);
4029         mutex_unlock(&fs_info->volume_mutex);
4030 out:
4031         btrfs_free_path(path);
4032         return ret;
4033 }
4034
4035 int btrfs_pause_balance(struct btrfs_fs_info *fs_info)
4036 {
4037         int ret = 0;
4038
4039         mutex_lock(&fs_info->balance_mutex);
4040         if (!fs_info->balance_ctl) {
4041                 mutex_unlock(&fs_info->balance_mutex);
4042                 return -ENOTCONN;
4043         }
4044
4045         if (atomic_read(&fs_info->balance_running)) {
4046                 atomic_inc(&fs_info->balance_pause_req);
4047                 mutex_unlock(&fs_info->balance_mutex);
4048
4049                 wait_event(fs_info->balance_wait_q,
4050                            atomic_read(&fs_info->balance_running) == 0);
4051
4052                 mutex_lock(&fs_info->balance_mutex);
4053                 /* we are good with balance_ctl ripped off from under us */
4054                 BUG_ON(atomic_read(&fs_info->balance_running));
4055                 atomic_dec(&fs_info->balance_pause_req);
4056         } else {
4057                 ret = -ENOTCONN;
4058         }
4059
4060         mutex_unlock(&fs_info->balance_mutex);
4061         return ret;
4062 }
4063
4064 int btrfs_cancel_balance(struct btrfs_fs_info *fs_info)
4065 {
4066         if (sb_rdonly(fs_info->sb))
4067                 return -EROFS;
4068
4069         mutex_lock(&fs_info->balance_mutex);
4070         if (!fs_info->balance_ctl) {
4071                 mutex_unlock(&fs_info->balance_mutex);
4072                 return -ENOTCONN;
4073         }
4074
4075         atomic_inc(&fs_info->balance_cancel_req);
4076         /*
4077          * if we are running just wait and return, balance item is
4078          * deleted in btrfs_balance in this case
4079          */
4080         if (atomic_read(&fs_info->balance_running)) {
4081                 mutex_unlock(&fs_info->balance_mutex);
4082                 wait_event(fs_info->balance_wait_q,
4083                            atomic_read(&fs_info->balance_running) == 0);
4084                 mutex_lock(&fs_info->balance_mutex);
4085         } else {
4086                 /* __cancel_balance needs volume_mutex */
4087                 mutex_unlock(&fs_info->balance_mutex);
4088                 mutex_lock(&fs_info->volume_mutex);
4089                 mutex_lock(&fs_info->balance_mutex);
4090
4091                 if (fs_info->balance_ctl)
4092                         __cancel_balance(fs_info);
4093
4094                 mutex_unlock(&fs_info->volume_mutex);
4095         }
4096
4097         BUG_ON(fs_info->balance_ctl || atomic_read(&fs_info->balance_running));
4098         atomic_dec(&fs_info->balance_cancel_req);
4099         mutex_unlock(&fs_info->balance_mutex);
4100         return 0;
4101 }
4102
4103 static int btrfs_uuid_scan_kthread(void *data)
4104 {
4105         struct btrfs_fs_info *fs_info = data;
4106         struct btrfs_root *root = fs_info->tree_root;
4107         struct btrfs_key key;
4108         struct btrfs_path *path = NULL;
4109         int ret = 0;
4110         struct extent_buffer *eb;
4111         int slot;
4112         struct btrfs_root_item root_item;
4113         u32 item_size;
4114         struct btrfs_trans_handle *trans = NULL;
4115
4116         path = btrfs_alloc_path();
4117         if (!path) {
4118                 ret = -ENOMEM;
4119                 goto out;
4120         }
4121
4122         key.objectid = 0;
4123         key.type = BTRFS_ROOT_ITEM_KEY;
4124         key.offset = 0;
4125
4126         while (1) {
4127                 ret = btrfs_search_forward(root, &key, path, 0);
4128                 if (ret) {
4129                         if (ret > 0)
4130                                 ret = 0;
4131                         break;
4132                 }
4133
4134                 if (key.type != BTRFS_ROOT_ITEM_KEY ||
4135                     (key.objectid < BTRFS_FIRST_FREE_OBJECTID &&
4136                      key.objectid != BTRFS_FS_TREE_OBJECTID) ||
4137                     key.objectid > BTRFS_LAST_FREE_OBJECTID)
4138                         goto skip;
4139
4140                 eb = path->nodes[0];
4141                 slot = path->slots[0];
4142                 item_size = btrfs_item_size_nr(eb, slot);
4143                 if (item_size < sizeof(root_item))
4144                         goto skip;
4145
4146                 read_extent_buffer(eb, &root_item,
4147                                    btrfs_item_ptr_offset(eb, slot),
4148                                    (int)sizeof(root_item));
4149                 if (btrfs_root_refs(&root_item) == 0)
4150                         goto skip;
4151
4152                 if (!btrfs_is_empty_uuid(root_item.uuid) ||
4153                     !btrfs_is_empty_uuid(root_item.received_uuid)) {
4154                         if (trans)
4155                                 goto update_tree;
4156
4157                         btrfs_release_path(path);
4158                         /*
4159                          * 1 - subvol uuid item
4160                          * 1 - received_subvol uuid item
4161                          */
4162                         trans = btrfs_start_transaction(fs_info->uuid_root, 2);
4163                         if (IS_ERR(trans)) {
4164                                 ret = PTR_ERR(trans);
4165                                 break;
4166                         }
4167                         continue;
4168                 } else {
4169                         goto skip;
4170                 }
4171 update_tree:
4172                 if (!btrfs_is_empty_uuid(root_item.uuid)) {
4173                         ret = btrfs_uuid_tree_add(trans, fs_info,
4174                                                   root_item.uuid,
4175                                                   BTRFS_UUID_KEY_SUBVOL,
4176                                                   key.objectid);
4177                         if (ret < 0) {
4178                                 btrfs_warn(fs_info, "uuid_tree_add failed %d",
4179                                         ret);
4180                                 break;
4181                         }
4182                 }
4183
4184                 if (!btrfs_is_empty_uuid(root_item.received_uuid)) {
4185                         ret = btrfs_uuid_tree_add(trans, fs_info,
4186                                                   root_item.received_uuid,
4187                                                  BTRFS_UUID_KEY_RECEIVED_SUBVOL,
4188                                                   key.objectid);
4189                         if (ret < 0) {
4190                                 btrfs_warn(fs_info, "uuid_tree_add failed %d",
4191                                         ret);
4192                                 break;
4193                         }
4194                 }
4195
4196 skip:
4197                 if (trans) {
4198                         ret = btrfs_end_transaction(trans);
4199                         trans = NULL;
4200                         if (ret)
4201                                 break;
4202                 }
4203
4204                 btrfs_release_path(path);
4205                 if (key.offset < (u64)-1) {
4206                         key.offset++;
4207                 } else if (key.type < BTRFS_ROOT_ITEM_KEY) {
4208                         key.offset = 0;
4209                         key.type = BTRFS_ROOT_ITEM_KEY;
4210                 } else if (key.objectid < (u64)-1) {
4211                         key.offset = 0;
4212                         key.type = BTRFS_ROOT_ITEM_KEY;
4213                         key.objectid++;
4214                 } else {
4215                         break;
4216                 }
4217                 cond_resched();
4218         }
4219
4220 out:
4221         btrfs_free_path(path);
4222         if (trans && !IS_ERR(trans))
4223                 btrfs_end_transaction(trans);
4224         if (ret)
4225                 btrfs_warn(fs_info, "btrfs_uuid_scan_kthread failed %d", ret);
4226         else
4227                 set_bit(BTRFS_FS_UPDATE_UUID_TREE_GEN, &fs_info->flags);
4228         up(&fs_info->uuid_tree_rescan_sem);
4229         return 0;
4230 }
4231
4232 /*
4233  * Callback for btrfs_uuid_tree_iterate().
4234  * returns:
4235  * 0    check succeeded, the entry is not outdated.
4236  * < 0  if an error occurred.
4237  * > 0  if the check failed, which means the caller shall remove the entry.
4238  */
4239 static int btrfs_check_uuid_tree_entry(struct btrfs_fs_info *fs_info,
4240                                        u8 *uuid, u8 type, u64 subid)
4241 {
4242         struct btrfs_key key;
4243         int ret = 0;
4244         struct btrfs_root *subvol_root;
4245
4246         if (type != BTRFS_UUID_KEY_SUBVOL &&
4247             type != BTRFS_UUID_KEY_RECEIVED_SUBVOL)
4248                 goto out;
4249
4250         key.objectid = subid;
4251         key.type = BTRFS_ROOT_ITEM_KEY;
4252         key.offset = (u64)-1;
4253         subvol_root = btrfs_read_fs_root_no_name(fs_info, &key);
4254         if (IS_ERR(subvol_root)) {
4255                 ret = PTR_ERR(subvol_root);
4256                 if (ret == -ENOENT)
4257                         ret = 1;
4258                 goto out;
4259         }
4260
4261         switch (type) {
4262         case BTRFS_UUID_KEY_SUBVOL:
4263                 if (memcmp(uuid, subvol_root->root_item.uuid, BTRFS_UUID_SIZE))
4264                         ret = 1;
4265                 break;
4266         case BTRFS_UUID_KEY_RECEIVED_SUBVOL:
4267                 if (memcmp(uuid, subvol_root->root_item.received_uuid,
4268                            BTRFS_UUID_SIZE))
4269                         ret = 1;
4270                 break;
4271         }
4272
4273 out:
4274         return ret;
4275 }
4276
4277 static int btrfs_uuid_rescan_kthread(void *data)
4278 {
4279         struct btrfs_fs_info *fs_info = (struct btrfs_fs_info *)data;
4280         int ret;
4281
4282         /*
4283          * 1st step is to iterate through the existing UUID tree and
4284          * to delete all entries that contain outdated data.
4285          * 2nd step is to add all missing entries to the UUID tree.
4286          */
4287         ret = btrfs_uuid_tree_iterate(fs_info, btrfs_check_uuid_tree_entry);
4288         if (ret < 0) {
4289                 btrfs_warn(fs_info, "iterating uuid_tree failed %d", ret);
4290                 up(&fs_info->uuid_tree_rescan_sem);
4291                 return ret;
4292         }
4293         return btrfs_uuid_scan_kthread(data);
4294 }
4295
4296 int btrfs_create_uuid_tree(struct btrfs_fs_info *fs_info)
4297 {
4298         struct btrfs_trans_handle *trans;
4299         struct btrfs_root *tree_root = fs_info->tree_root;
4300         struct btrfs_root *uuid_root;
4301         struct task_struct *task;
4302         int ret;
4303
4304         /*
4305          * 1 - root node
4306          * 1 - root item
4307          */
4308         trans = btrfs_start_transaction(tree_root, 2);
4309         if (IS_ERR(trans))
4310                 return PTR_ERR(trans);
4311
4312         uuid_root = btrfs_create_tree(trans, fs_info,
4313                                       BTRFS_UUID_TREE_OBJECTID);
4314         if (IS_ERR(uuid_root)) {
4315                 ret = PTR_ERR(uuid_root);
4316                 btrfs_abort_transaction(trans, ret);
4317                 btrfs_end_transaction(trans);
4318                 return ret;
4319         }
4320
4321         fs_info->uuid_root = uuid_root;
4322
4323         ret = btrfs_commit_transaction(trans);
4324         if (ret)
4325                 return ret;
4326
4327         down(&fs_info->uuid_tree_rescan_sem);
4328         task = kthread_run(btrfs_uuid_scan_kthread, fs_info, "btrfs-uuid");
4329         if (IS_ERR(task)) {
4330                 /* fs_info->update_uuid_tree_gen remains 0 in all error case */
4331                 btrfs_warn(fs_info, "failed to start uuid_scan task");
4332                 up(&fs_info->uuid_tree_rescan_sem);
4333                 return PTR_ERR(task);
4334         }
4335
4336         return 0;
4337 }
4338
4339 int btrfs_check_uuid_tree(struct btrfs_fs_info *fs_info)
4340 {
4341         struct task_struct *task;
4342
4343         down(&fs_info->uuid_tree_rescan_sem);
4344         task = kthread_run(btrfs_uuid_rescan_kthread, fs_info, "btrfs-uuid");
4345         if (IS_ERR(task)) {
4346                 /* fs_info->update_uuid_tree_gen remains 0 in all error case */
4347                 btrfs_warn(fs_info, "failed to start uuid_rescan task");
4348                 up(&fs_info->uuid_tree_rescan_sem);
4349                 return PTR_ERR(task);
4350         }
4351
4352         return 0;
4353 }
4354
4355 /*
4356  * shrinking a device means finding all of the device extents past
4357  * the new size, and then following the back refs to the chunks.
4358  * The chunk relocation code actually frees the device extent
4359  */
4360 int btrfs_shrink_device(struct btrfs_device *device, u64 new_size)
4361 {
4362         struct btrfs_fs_info *fs_info = device->fs_info;
4363         struct btrfs_root *root = fs_info->dev_root;
4364         struct btrfs_trans_handle *trans;
4365         struct btrfs_dev_extent *dev_extent = NULL;
4366         struct btrfs_path *path;
4367         u64 length;
4368         u64 chunk_offset;
4369         int ret;
4370         int slot;
4371         int failed = 0;
4372         bool retried = false;
4373         bool checked_pending_chunks = false;
4374         struct extent_buffer *l;
4375         struct btrfs_key key;
4376         struct btrfs_super_block *super_copy = fs_info->super_copy;
4377         u64 old_total = btrfs_super_total_bytes(super_copy);
4378         u64 old_size = btrfs_device_get_total_bytes(device);
4379         u64 diff;
4380
4381         new_size = round_down(new_size, fs_info->sectorsize);
4382         diff = round_down(old_size - new_size, fs_info->sectorsize);
4383
4384         if (device->is_tgtdev_for_dev_replace)
4385                 return -EINVAL;
4386
4387         path = btrfs_alloc_path();
4388         if (!path)
4389                 return -ENOMEM;
4390
4391         path->reada = READA_FORWARD;
4392
4393         mutex_lock(&fs_info->chunk_mutex);
4394
4395         btrfs_device_set_total_bytes(device, new_size);
4396         if (device->writeable) {
4397                 device->fs_devices->total_rw_bytes -= diff;
4398                 atomic64_sub(diff, &fs_info->free_chunk_space);
4399         }
4400         mutex_unlock(&fs_info->chunk_mutex);
4401
4402 again:
4403         key.objectid = device->devid;
4404         key.offset = (u64)-1;
4405         key.type = BTRFS_DEV_EXTENT_KEY;
4406
4407         do {
4408                 mutex_lock(&fs_info->delete_unused_bgs_mutex);
4409                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
4410                 if (ret < 0) {
4411                         mutex_unlock(&fs_info->delete_unused_bgs_mutex);
4412                         goto done;
4413                 }
4414
4415                 ret = btrfs_previous_item(root, path, 0, key.type);
4416                 if (ret)
4417                         mutex_unlock(&fs_info->delete_unused_bgs_mutex);
4418                 if (ret < 0)
4419                         goto done;
4420                 if (ret) {
4421                         ret = 0;
4422                         btrfs_release_path(path);
4423                         break;
4424                 }
4425
4426                 l = path->nodes[0];
4427                 slot = path->slots[0];
4428                 btrfs_item_key_to_cpu(l, &key, path->slots[0]);
4429
4430                 if (key.objectid != device->devid) {
4431                         mutex_unlock(&fs_info->delete_unused_bgs_mutex);
4432                         btrfs_release_path(path);
4433                         break;
4434                 }
4435
4436                 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
4437                 length = btrfs_dev_extent_length(l, dev_extent);
4438
4439                 if (key.offset + length <= new_size) {
4440                         mutex_unlock(&fs_info->delete_unused_bgs_mutex);
4441                         btrfs_release_path(path);
4442                         break;
4443                 }
4444
4445                 chunk_offset = btrfs_dev_extent_chunk_offset(l, dev_extent);
4446                 btrfs_release_path(path);
4447
4448                 ret = btrfs_relocate_chunk(fs_info, chunk_offset);
4449                 mutex_unlock(&fs_info->delete_unused_bgs_mutex);
4450                 if (ret && ret != -ENOSPC)
4451                         goto done;
4452                 if (ret == -ENOSPC)
4453                         failed++;
4454         } while (key.offset-- > 0);
4455
4456         if (failed && !retried) {
4457                 failed = 0;
4458                 retried = true;
4459                 goto again;
4460         } else if (failed && retried) {
4461                 ret = -ENOSPC;
4462                 goto done;
4463         }
4464
4465         /* Shrinking succeeded, else we would be at "done". */
4466         trans = btrfs_start_transaction(root, 0);
4467         if (IS_ERR(trans)) {
4468                 ret = PTR_ERR(trans);
4469                 goto done;
4470         }
4471
4472         mutex_lock(&fs_info->chunk_mutex);
4473
4474         /*
4475          * We checked in the above loop all device extents that were already in
4476          * the device tree. However before we have updated the device's
4477          * total_bytes to the new size, we might have had chunk allocations that
4478          * have not complete yet (new block groups attached to transaction
4479          * handles), and therefore their device extents were not yet in the
4480          * device tree and we missed them in the loop above. So if we have any
4481          * pending chunk using a device extent that overlaps the device range
4482          * that we can not use anymore, commit the current transaction and
4483          * repeat the search on the device tree - this way we guarantee we will
4484          * not have chunks using device extents that end beyond 'new_size'.
4485          */
4486         if (!checked_pending_chunks) {
4487                 u64 start = new_size;
4488                 u64 len = old_size - new_size;
4489
4490                 if (contains_pending_extent(trans->transaction, device,
4491                                             &start, len)) {
4492                         mutex_unlock(&fs_info->chunk_mutex);
4493                         checked_pending_chunks = true;
4494                         failed = 0;
4495                         retried = false;
4496                         ret = btrfs_commit_transaction(trans);
4497                         if (ret)
4498                                 goto done;
4499                         goto again;
4500                 }
4501         }
4502
4503         btrfs_device_set_disk_total_bytes(device, new_size);
4504         if (list_empty(&device->resized_list))
4505                 list_add_tail(&device->resized_list,
4506                               &fs_info->fs_devices->resized_devices);
4507
4508         WARN_ON(diff > old_total);
4509         btrfs_set_super_total_bytes(super_copy,
4510                         round_down(old_total - diff, fs_info->sectorsize));
4511         mutex_unlock(&fs_info->chunk_mutex);
4512
4513         /* Now btrfs_update_device() will change the on-disk size. */
4514         ret = btrfs_update_device(trans, device);
4515         btrfs_end_transaction(trans);
4516 done:
4517         btrfs_free_path(path);
4518         if (ret) {
4519                 mutex_lock(&fs_info->chunk_mutex);
4520                 btrfs_device_set_total_bytes(device, old_size);
4521                 if (device->writeable)
4522                         device->fs_devices->total_rw_bytes += diff;
4523                 atomic64_add(diff, &fs_info->free_chunk_space);
4524                 mutex_unlock(&fs_info->chunk_mutex);
4525         }
4526         return ret;
4527 }
4528
4529 static int btrfs_add_system_chunk(struct btrfs_fs_info *fs_info,
4530                            struct btrfs_key *key,
4531                            struct btrfs_chunk *chunk, int item_size)
4532 {
4533         struct btrfs_super_block *super_copy = fs_info->super_copy;
4534         struct btrfs_disk_key disk_key;
4535         u32 array_size;
4536         u8 *ptr;
4537
4538         mutex_lock(&fs_info->chunk_mutex);
4539         array_size = btrfs_super_sys_array_size(super_copy);
4540         if (array_size + item_size + sizeof(disk_key)
4541                         > BTRFS_SYSTEM_CHUNK_ARRAY_SIZE) {
4542                 mutex_unlock(&fs_info->chunk_mutex);
4543                 return -EFBIG;
4544         }
4545
4546         ptr = super_copy->sys_chunk_array + array_size;
4547         btrfs_cpu_key_to_disk(&disk_key, key);
4548         memcpy(ptr, &disk_key, sizeof(disk_key));
4549         ptr += sizeof(disk_key);
4550         memcpy(ptr, chunk, item_size);
4551         item_size += sizeof(disk_key);
4552         btrfs_set_super_sys_array_size(super_copy, array_size + item_size);
4553         mutex_unlock(&fs_info->chunk_mutex);
4554
4555         return 0;
4556 }
4557
4558 /*
4559  * sort the devices in descending order by max_avail, total_avail
4560  */
4561 static int btrfs_cmp_device_info(const void *a, const void *b)
4562 {
4563         const struct btrfs_device_info *di_a = a;
4564         const struct btrfs_device_info *di_b = b;
4565
4566         if (di_a->max_avail > di_b->max_avail)
4567                 return -1;
4568         if (di_a->max_avail < di_b->max_avail)
4569                 return 1;
4570         if (di_a->total_avail > di_b->total_avail)
4571                 return -1;
4572         if (di_a->total_avail < di_b->total_avail)
4573                 return 1;
4574         return 0;
4575 }
4576
4577 static void check_raid56_incompat_flag(struct btrfs_fs_info *info, u64 type)
4578 {
4579         if (!(type & BTRFS_BLOCK_GROUP_RAID56_MASK))
4580                 return;
4581
4582         btrfs_set_fs_incompat(info, RAID56);
4583 }
4584
4585 #define BTRFS_MAX_DEVS(r) ((BTRFS_MAX_ITEM_SIZE(r->fs_info)             \
4586                         - sizeof(struct btrfs_chunk))           \
4587                         / sizeof(struct btrfs_stripe) + 1)
4588
4589 #define BTRFS_MAX_DEVS_SYS_CHUNK ((BTRFS_SYSTEM_CHUNK_ARRAY_SIZE        \
4590                                 - 2 * sizeof(struct btrfs_disk_key)     \
4591                                 - 2 * sizeof(struct btrfs_chunk))       \
4592                                 / sizeof(struct btrfs_stripe) + 1)
4593
4594 static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
4595                                u64 start, u64 type)
4596 {
4597         struct btrfs_fs_info *info = trans->fs_info;
4598         struct btrfs_fs_devices *fs_devices = info->fs_devices;
4599         struct btrfs_device *device;
4600         struct map_lookup *map = NULL;
4601         struct extent_map_tree *em_tree;
4602         struct extent_map *em;
4603         struct btrfs_device_info *devices_info = NULL;
4604         u64 total_avail;
4605         int num_stripes;        /* total number of stripes to allocate */
4606         int data_stripes;       /* number of stripes that count for
4607                                    block group size */
4608         int sub_stripes;        /* sub_stripes info for map */
4609         int dev_stripes;        /* stripes per dev */
4610         int devs_max;           /* max devs to use */
4611         int devs_min;           /* min devs needed */
4612         int devs_increment;     /* ndevs has to be a multiple of this */
4613         int ncopies;            /* how many copies to data has */
4614         int ret;
4615         u64 max_stripe_size;
4616         u64 max_chunk_size;
4617         u64 stripe_size;
4618         u64 num_bytes;
4619         int ndevs;
4620         int i;
4621         int j;
4622         int index;
4623
4624         BUG_ON(!alloc_profile_is_valid(type, 0));
4625
4626         if (list_empty(&fs_devices->alloc_list))
4627                 return -ENOSPC;
4628
4629         index = __get_raid_index(type);
4630
4631         sub_stripes = btrfs_raid_array[index].sub_stripes;
4632         dev_stripes = btrfs_raid_array[index].dev_stripes;
4633         devs_max = btrfs_raid_array[index].devs_max;
4634         devs_min = btrfs_raid_array[index].devs_min;
4635         devs_increment = btrfs_raid_array[index].devs_increment;
4636         ncopies = btrfs_raid_array[index].ncopies;
4637
4638         if (type & BTRFS_BLOCK_GROUP_DATA) {
4639                 max_stripe_size = SZ_1G;
4640                 max_chunk_size = 10 * max_stripe_size;
4641                 if (!devs_max)
4642                         devs_max = BTRFS_MAX_DEVS(info->chunk_root);
4643         } else if (type & BTRFS_BLOCK_GROUP_METADATA) {
4644                 /* for larger filesystems, use larger metadata chunks */
4645                 if (fs_devices->total_rw_bytes > 50ULL * SZ_1G)
4646                         max_stripe_size = SZ_1G;
4647                 else
4648                         max_stripe_size = SZ_256M;
4649                 max_chunk_size = max_stripe_size;
4650                 if (!devs_max)
4651                         devs_max = BTRFS_MAX_DEVS(info->chunk_root);
4652         } else if (type & BTRFS_BLOCK_GROUP_SYSTEM) {
4653                 max_stripe_size = SZ_32M;
4654                 max_chunk_size = 2 * max_stripe_size;
4655                 if (!devs_max)
4656                         devs_max = BTRFS_MAX_DEVS_SYS_CHUNK;
4657         } else {
4658                 btrfs_err(info, "invalid chunk type 0x%llx requested",
4659                        type);
4660                 BUG_ON(1);
4661         }
4662
4663         /* we don't want a chunk larger than 10% of writeable space */
4664         max_chunk_size = min(div_factor(fs_devices->total_rw_bytes, 1),
4665                              max_chunk_size);
4666
4667         devices_info = kcalloc(fs_devices->rw_devices, sizeof(*devices_info),
4668                                GFP_NOFS);
4669         if (!devices_info)
4670                 return -ENOMEM;
4671
4672         /*
4673          * in the first pass through the devices list, we gather information
4674          * about the available holes on each device.
4675          */
4676         ndevs = 0;
4677         list_for_each_entry(device, &fs_devices->alloc_list, dev_alloc_list) {
4678                 u64 max_avail;
4679                 u64 dev_offset;
4680
4681                 if (!device->writeable) {
4682                         WARN(1, KERN_ERR
4683                                "BTRFS: read-only device in alloc_list\n");
4684                         continue;
4685                 }
4686
4687                 if (!device->in_fs_metadata ||
4688                     device->is_tgtdev_for_dev_replace)
4689                         continue;
4690
4691                 if (device->total_bytes > device->bytes_used)
4692                         total_avail = device->total_bytes - device->bytes_used;
4693                 else
4694                         total_avail = 0;
4695
4696                 /* If there is no space on this device, skip it. */
4697                 if (total_avail == 0)
4698                         continue;
4699
4700                 ret = find_free_dev_extent(trans, device,
4701                                            max_stripe_size * dev_stripes,
4702                                            &dev_offset, &max_avail);
4703                 if (ret && ret != -ENOSPC)
4704                         goto error;
4705
4706                 if (ret == 0)
4707                         max_avail = max_stripe_size * dev_stripes;
4708
4709                 if (max_avail < BTRFS_STRIPE_LEN * dev_stripes)
4710                         continue;
4711
4712                 if (ndevs == fs_devices->rw_devices) {
4713                         WARN(1, "%s: found more than %llu devices\n",
4714                              __func__, fs_devices->rw_devices);
4715                         break;
4716                 }
4717                 devices_info[ndevs].dev_offset = dev_offset;
4718                 devices_info[ndevs].max_avail = max_avail;
4719                 devices_info[ndevs].total_avail = total_avail;
4720                 devices_info[ndevs].dev = device;
4721                 ++ndevs;
4722         }
4723
4724         /*
4725          * now sort the devices by hole size / available space
4726          */
4727         sort(devices_info, ndevs, sizeof(struct btrfs_device_info),
4728              btrfs_cmp_device_info, NULL);
4729
4730         /* round down to number of usable stripes */
4731         ndevs = round_down(ndevs, devs_increment);
4732
4733         if (ndevs < devs_increment * sub_stripes || ndevs < devs_min) {
4734                 ret = -ENOSPC;
4735                 goto error;
4736         }
4737
4738         ndevs = min(ndevs, devs_max);
4739
4740         /*
4741          * the primary goal is to maximize the number of stripes, so use as many
4742          * devices as possible, even if the stripes are not maximum sized.
4743          */
4744         stripe_size = devices_info[ndevs-1].max_avail;
4745         num_stripes = ndevs * dev_stripes;
4746
4747         /*
4748          * this will have to be fixed for RAID1 and RAID10 over
4749          * more drives
4750          */
4751         data_stripes = num_stripes / ncopies;
4752
4753         if (type & BTRFS_BLOCK_GROUP_RAID5)
4754                 data_stripes = num_stripes - 1;
4755
4756         if (type & BTRFS_BLOCK_GROUP_RAID6)
4757                 data_stripes = num_stripes - 2;
4758
4759         /*
4760          * Use the number of data stripes to figure out how big this chunk
4761          * is really going to be in terms of logical address space,
4762          * and compare that answer with the max chunk size
4763          */
4764         if (stripe_size * data_stripes > max_chunk_size) {
4765                 u64 mask = (1ULL << 24) - 1;
4766
4767                 stripe_size = div_u64(max_chunk_size, data_stripes);
4768
4769                 /* bump the answer up to a 16MB boundary */
4770                 stripe_size = (stripe_size + mask) & ~mask;
4771
4772                 /* but don't go higher than the limits we found
4773                  * while searching for free extents
4774                  */
4775                 if (stripe_size > devices_info[ndevs-1].max_avail)
4776                         stripe_size = devices_info[ndevs-1].max_avail;
4777         }
4778
4779         stripe_size = div_u64(stripe_size, dev_stripes);
4780
4781         /* align to BTRFS_STRIPE_LEN */
4782         stripe_size = round_down(stripe_size, BTRFS_STRIPE_LEN);
4783
4784         map = kmalloc(map_lookup_size(num_stripes), GFP_NOFS);
4785         if (!map) {
4786                 ret = -ENOMEM;
4787                 goto error;
4788         }
4789         map->num_stripes = num_stripes;
4790
4791         for (i = 0; i < ndevs; ++i) {
4792                 for (j = 0; j < dev_stripes; ++j) {
4793                         int s = i * dev_stripes + j;
4794                         map->stripes[s].dev = devices_info[i].dev;
4795                         map->stripes[s].physical = devices_info[i].dev_offset +
4796                                                    j * stripe_size;
4797                 }
4798         }
4799         map->stripe_len = BTRFS_STRIPE_LEN;
4800         map->io_align = BTRFS_STRIPE_LEN;
4801         map->io_width = BTRFS_STRIPE_LEN;
4802         map->type = type;
4803         map->sub_stripes = sub_stripes;
4804
4805         num_bytes = stripe_size * data_stripes;
4806
4807         trace_btrfs_chunk_alloc(info, map, start, num_bytes);
4808
4809         em = alloc_extent_map();
4810         if (!em) {
4811                 kfree(map);
4812                 ret = -ENOMEM;
4813                 goto error;
4814         }
4815         set_bit(EXTENT_FLAG_FS_MAPPING, &em->flags);
4816         em->map_lookup = map;
4817         em->start = start;
4818         em->len = num_bytes;
4819         em->block_start = 0;
4820         em->block_len = em->len;
4821         em->orig_block_len = stripe_size;
4822
4823         em_tree = &info->mapping_tree.map_tree;
4824         write_lock(&em_tree->lock);
4825         ret = add_extent_mapping(em_tree, em, 0);
4826         if (ret) {
4827                 write_unlock(&em_tree->lock);
4828                 free_extent_map(em);
4829                 goto error;
4830         }
4831
4832         list_add_tail(&em->list, &trans->transaction->pending_chunks);
4833         refcount_inc(&em->refs);
4834         write_unlock(&em_tree->lock);
4835
4836         ret = btrfs_make_block_group(trans, info, 0, type, start, num_bytes);
4837         if (ret)
4838                 goto error_del_extent;
4839
4840         for (i = 0; i < map->num_stripes; i++) {
4841                 num_bytes = map->stripes[i].dev->bytes_used + stripe_size;
4842                 btrfs_device_set_bytes_used(map->stripes[i].dev, num_bytes);
4843         }
4844
4845         atomic64_sub(stripe_size * map->num_stripes, &info->free_chunk_space);
4846
4847         free_extent_map(em);
4848         check_raid56_incompat_flag(info, type);
4849
4850         kfree(devices_info);
4851         return 0;
4852
4853 error_del_extent:
4854         write_lock(&em_tree->lock);
4855         remove_extent_mapping(em_tree, em);
4856         write_unlock(&em_tree->lock);
4857
4858         /* One for our allocation */
4859         free_extent_map(em);
4860         /* One for the tree reference */
4861         free_extent_map(em);
4862         /* One for the pending_chunks list reference */
4863         free_extent_map(em);
4864 error:
4865         kfree(devices_info);
4866         return ret;
4867 }
4868
4869 int btrfs_finish_chunk_alloc(struct btrfs_trans_handle *trans,
4870                                 struct btrfs_fs_info *fs_info,
4871                                 u64 chunk_offset, u64 chunk_size)
4872 {
4873         struct btrfs_root *extent_root = fs_info->extent_root;
4874         struct btrfs_root *chunk_root = fs_info->chunk_root;
4875         struct btrfs_key key;
4876         struct btrfs_device *device;
4877         struct btrfs_chunk *chunk;
4878         struct btrfs_stripe *stripe;
4879         struct extent_map *em;
4880         struct map_lookup *map;
4881         size_t item_size;
4882         u64 dev_offset;
4883         u64 stripe_size;
4884         int i = 0;
4885         int ret = 0;
4886
4887         em = get_chunk_map(fs_info, chunk_offset, chunk_size);
4888         if (IS_ERR(em))
4889                 return PTR_ERR(em);
4890
4891         map = em->map_lookup;
4892         item_size = btrfs_chunk_item_size(map->num_stripes);
4893         stripe_size = em->orig_block_len;
4894
4895         chunk = kzalloc(item_size, GFP_NOFS);
4896         if (!chunk) {
4897                 ret = -ENOMEM;
4898                 goto out;
4899         }
4900
4901         /*
4902          * Take the device list mutex to prevent races with the final phase of
4903          * a device replace operation that replaces the device object associated
4904          * with the map's stripes, because the device object's id can change
4905          * at any time during that final phase of the device replace operation
4906          * (dev-replace.c:btrfs_dev_replace_finishing()).
4907          */
4908         mutex_lock(&fs_info->fs_devices->device_list_mutex);
4909         for (i = 0; i < map->num_stripes; i++) {
4910                 device = map->stripes[i].dev;
4911                 dev_offset = map->stripes[i].physical;
4912
4913                 ret = btrfs_update_device(trans, device);
4914                 if (ret)
4915                         break;
4916                 ret = btrfs_alloc_dev_extent(trans, device, chunk_offset,
4917                                              dev_offset, stripe_size);
4918                 if (ret)
4919                         break;
4920         }
4921         if (ret) {
4922                 mutex_unlock(&fs_info->fs_devices->device_list_mutex);
4923                 goto out;
4924         }
4925
4926         stripe = &chunk->stripe;
4927         for (i = 0; i < map->num_stripes; i++) {
4928                 device = map->stripes[i].dev;
4929                 dev_offset = map->stripes[i].physical;
4930
4931                 btrfs_set_stack_stripe_devid(stripe, device->devid);
4932                 btrfs_set_stack_stripe_offset(stripe, dev_offset);
4933                 memcpy(stripe->dev_uuid, device->uuid, BTRFS_UUID_SIZE);
4934                 stripe++;
4935         }
4936         mutex_unlock(&fs_info->fs_devices->device_list_mutex);
4937
4938         btrfs_set_stack_chunk_length(chunk, chunk_size);
4939         btrfs_set_stack_chunk_owner(chunk, extent_root->root_key.objectid);
4940         btrfs_set_stack_chunk_stripe_len(chunk, map->stripe_len);
4941         btrfs_set_stack_chunk_type(chunk, map->type);
4942         btrfs_set_stack_chunk_num_stripes(chunk, map->num_stripes);
4943         btrfs_set_stack_chunk_io_align(chunk, map->stripe_len);
4944         btrfs_set_stack_chunk_io_width(chunk, map->stripe_len);
4945         btrfs_set_stack_chunk_sector_size(chunk, fs_info->sectorsize);
4946         btrfs_set_stack_chunk_sub_stripes(chunk, map->sub_stripes);
4947
4948         key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
4949         key.type = BTRFS_CHUNK_ITEM_KEY;
4950         key.offset = chunk_offset;
4951
4952         ret = btrfs_insert_item(trans, chunk_root, &key, chunk, item_size);
4953         if (ret == 0 && map->type & BTRFS_BLOCK_GROUP_SYSTEM) {
4954                 /*
4955                  * TODO: Cleanup of inserted chunk root in case of
4956                  * failure.
4957                  */
4958                 ret = btrfs_add_system_chunk(fs_info, &key, chunk, item_size);
4959         }
4960
4961 out:
4962         kfree(chunk);
4963         free_extent_map(em);
4964         return ret;
4965 }
4966
4967 /*
4968  * Chunk allocation falls into two parts. The first part does works
4969  * that make the new allocated chunk useable, but not do any operation
4970  * that modifies the chunk tree. The second part does the works that
4971  * require modifying the chunk tree. This division is important for the
4972  * bootstrap process of adding storage to a seed btrfs.
4973  */
4974 int btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
4975                       struct btrfs_fs_info *fs_info, u64 type)
4976 {
4977         u64 chunk_offset;
4978
4979         ASSERT(mutex_is_locked(&fs_info->chunk_mutex));
4980         chunk_offset = find_next_chunk(fs_info);
4981         return __btrfs_alloc_chunk(trans, chunk_offset, type);
4982 }
4983
4984 static noinline int init_first_rw_device(struct btrfs_trans_handle *trans,
4985                                          struct btrfs_fs_info *fs_info)
4986 {
4987         u64 chunk_offset;
4988         u64 sys_chunk_offset;
4989         u64 alloc_profile;
4990         int ret;
4991
4992         chunk_offset = find_next_chunk(fs_info);
4993         alloc_profile = btrfs_metadata_alloc_profile(fs_info);
4994         ret = __btrfs_alloc_chunk(trans, chunk_offset, alloc_profile);
4995         if (ret)
4996                 return ret;
4997
4998         sys_chunk_offset = find_next_chunk(fs_info);
4999         alloc_profile = btrfs_system_alloc_profile(fs_info);
5000         ret = __btrfs_alloc_chunk(trans, sys_chunk_offset, alloc_profile);
5001         return ret;
5002 }
5003
5004 static inline int btrfs_chunk_max_errors(struct map_lookup *map)
5005 {
5006         int max_errors;
5007
5008         if (map->type & (BTRFS_BLOCK_GROUP_RAID1 |
5009                          BTRFS_BLOCK_GROUP_RAID10 |
5010                          BTRFS_BLOCK_GROUP_RAID5 |
5011                          BTRFS_BLOCK_GROUP_DUP)) {
5012                 max_errors = 1;
5013         } else if (map->type & BTRFS_BLOCK_GROUP_RAID6) {
5014                 max_errors = 2;
5015         } else {
5016                 max_errors = 0;
5017         }
5018
5019         return max_errors;
5020 }
5021
5022 int btrfs_chunk_readonly(struct btrfs_fs_info *fs_info, u64 chunk_offset)
5023 {
5024         struct extent_map *em;
5025         struct map_lookup *map;
5026         int readonly = 0;
5027         int miss_ndevs = 0;
5028         int i;
5029
5030         em = get_chunk_map(fs_info, chunk_offset, 1);
5031         if (IS_ERR(em))
5032                 return 1;
5033
5034         map = em->map_lookup;
5035         for (i = 0; i < map->num_stripes; i++) {
5036                 if (map->stripes[i].dev->missing) {
5037                         miss_ndevs++;
5038                         continue;
5039                 }
5040
5041                 if (!map->stripes[i].dev->writeable) {
5042                         readonly = 1;
5043                         goto end;
5044                 }
5045         }
5046
5047         /*
5048          * If the number of missing devices is larger than max errors,
5049          * we can not write the data into that chunk successfully, so
5050          * set it readonly.
5051          */
5052         if (miss_ndevs > btrfs_chunk_max_errors(map))
5053                 readonly = 1;
5054 end:
5055         free_extent_map(em);
5056         return readonly;
5057 }
5058
5059 void btrfs_mapping_init(struct btrfs_mapping_tree *tree)
5060 {
5061         extent_map_tree_init(&tree->map_tree);
5062 }
5063
5064 void btrfs_mapping_tree_free(struct btrfs_mapping_tree *tree)
5065 {
5066         struct extent_map *em;
5067
5068         while (1) {
5069                 write_lock(&tree->map_tree.lock);
5070                 em = lookup_extent_mapping(&tree->map_tree, 0, (u64)-1);
5071                 if (em)
5072                         remove_extent_mapping(&tree->map_tree, em);
5073                 write_unlock(&tree->map_tree.lock);
5074                 if (!em)
5075                         break;
5076                 /* once for us */
5077                 free_extent_map(em);
5078                 /* once for the tree */
5079                 free_extent_map(em);
5080         }
5081 }
5082
5083 int btrfs_num_copies(struct btrfs_fs_info *fs_info, u64 logical, u64 len)
5084 {
5085         struct extent_map *em;
5086         struct map_lookup *map;
5087         int ret;
5088
5089         em = get_chunk_map(fs_info, logical, len);
5090         if (IS_ERR(em))
5091                 /*
5092                  * We could return errors for these cases, but that could get
5093                  * ugly and we'd probably do the same thing which is just not do
5094                  * anything else and exit, so return 1 so the callers don't try
5095                  * to use other copies.
5096                  */
5097                 return 1;
5098
5099         map = em->map_lookup;
5100         if (map->type & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1))
5101                 ret = map->num_stripes;
5102         else if (map->type & BTRFS_BLOCK_GROUP_RAID10)
5103                 ret = map->sub_stripes;
5104         else if (map->type & BTRFS_BLOCK_GROUP_RAID5)
5105                 ret = 2;
5106         else if (map->type & BTRFS_BLOCK_GROUP_RAID6)
5107                 ret = 3;
5108         else
5109                 ret = 1;
5110         free_extent_map(em);
5111
5112         btrfs_dev_replace_lock(&fs_info->dev_replace, 0);
5113         if (btrfs_dev_replace_is_ongoing(&fs_info->dev_replace) &&
5114             fs_info->dev_replace.tgtdev)
5115                 ret++;
5116         btrfs_dev_replace_unlock(&fs_info->dev_replace, 0);
5117
5118         return ret;
5119 }
5120
5121 unsigned long btrfs_full_stripe_len(struct btrfs_fs_info *fs_info,
5122                                     u64 logical)
5123 {
5124         struct extent_map *em;
5125         struct map_lookup *map;
5126         unsigned long len = fs_info->sectorsize;
5127
5128         em = get_chunk_map(fs_info, logical, len);
5129
5130         if (!WARN_ON(IS_ERR(em))) {
5131                 map = em->map_lookup;
5132                 if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK)
5133                         len = map->stripe_len * nr_data_stripes(map);
5134                 free_extent_map(em);
5135         }
5136         return len;
5137 }
5138
5139 int btrfs_is_parity_mirror(struct btrfs_fs_info *fs_info, u64 logical, u64 len)
5140 {
5141         struct extent_map *em;
5142         struct map_lookup *map;
5143         int ret = 0;
5144
5145         em = get_chunk_map(fs_info, logical, len);
5146
5147         if(!WARN_ON(IS_ERR(em))) {
5148                 map = em->map_lookup;
5149                 if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK)
5150                         ret = 1;
5151                 free_extent_map(em);
5152         }
5153         return ret;
5154 }
5155
5156 static int find_live_mirror(struct btrfs_fs_info *fs_info,
5157                             struct map_lookup *map, int first, int num,
5158                             int optimal, int dev_replace_is_ongoing)
5159 {
5160         int i;
5161         int tolerance;
5162         struct btrfs_device *srcdev;
5163
5164         if (dev_replace_is_ongoing &&
5165             fs_info->dev_replace.cont_reading_from_srcdev_mode ==
5166              BTRFS_DEV_REPLACE_ITEM_CONT_READING_FROM_SRCDEV_MODE_AVOID)
5167                 srcdev = fs_info->dev_replace.srcdev;
5168         else
5169                 srcdev = NULL;
5170
5171         /*
5172          * try to avoid the drive that is the source drive for a
5173          * dev-replace procedure, only choose it if no other non-missing
5174          * mirror is available
5175          */
5176         for (tolerance = 0; tolerance < 2; tolerance++) {
5177                 if (map->stripes[optimal].dev->bdev &&
5178                     (tolerance || map->stripes[optimal].dev != srcdev))
5179                         return optimal;
5180                 for (i = first; i < first + num; i++) {
5181                         if (map->stripes[i].dev->bdev &&
5182                             (tolerance || map->stripes[i].dev != srcdev))
5183                                 return i;
5184                 }
5185         }
5186
5187         /* we couldn't find one that doesn't fail.  Just return something
5188          * and the io error handling code will clean up eventually
5189          */
5190         return optimal;
5191 }
5192
5193 static inline int parity_smaller(u64 a, u64 b)
5194 {
5195         return a > b;
5196 }
5197
5198 /* Bubble-sort the stripe set to put the parity/syndrome stripes last */
5199 static void sort_parity_stripes(struct btrfs_bio *bbio, int num_stripes)
5200 {
5201         struct btrfs_bio_stripe s;
5202         int i;
5203         u64 l;
5204         int again = 1;
5205
5206         while (again) {
5207                 again = 0;
5208                 for (i = 0; i < num_stripes - 1; i++) {
5209                         if (parity_smaller(bbio->raid_map[i],
5210                                            bbio->raid_map[i+1])) {
5211                                 s = bbio->stripes[i];
5212                                 l = bbio->raid_map[i];
5213                                 bbio->stripes[i] = bbio->stripes[i+1];
5214                                 bbio->raid_map[i] = bbio->raid_map[i+1];
5215                                 bbio->stripes[i+1] = s;
5216                                 bbio->raid_map[i+1] = l;
5217
5218                                 again = 1;
5219                         }
5220                 }
5221         }
5222 }
5223
5224 static struct btrfs_bio *alloc_btrfs_bio(int total_stripes, int real_stripes)
5225 {
5226         struct btrfs_bio *bbio = kzalloc(
5227                  /* the size of the btrfs_bio */
5228                 sizeof(struct btrfs_bio) +
5229                 /* plus the variable array for the stripes */
5230                 sizeof(struct btrfs_bio_stripe) * (total_stripes) +
5231                 /* plus the variable array for the tgt dev */
5232                 sizeof(int) * (real_stripes) +
5233                 /*
5234                  * plus the raid_map, which includes both the tgt dev
5235                  * and the stripes
5236                  */
5237                 sizeof(u64) * (total_stripes),
5238                 GFP_NOFS|__GFP_NOFAIL);
5239
5240         atomic_set(&bbio->error, 0);
5241         refcount_set(&bbio->refs, 1);
5242
5243         return bbio;
5244 }
5245
5246 void btrfs_get_bbio(struct btrfs_bio *bbio)
5247 {
5248         WARN_ON(!refcount_read(&bbio->refs));
5249         refcount_inc(&bbio->refs);
5250 }
5251
5252 void btrfs_put_bbio(struct btrfs_bio *bbio)
5253 {
5254         if (!bbio)
5255                 return;
5256         if (refcount_dec_and_test(&bbio->refs))
5257                 kfree(bbio);
5258 }
5259
5260 /* can REQ_OP_DISCARD be sent with other REQ like REQ_OP_WRITE? */
5261 /*
5262  * Please note that, discard won't be sent to target device of device
5263  * replace.
5264  */
5265 static int __btrfs_map_block_for_discard(struct btrfs_fs_info *fs_info,
5266                                          u64 logical, u64 length,
5267                                          struct btrfs_bio **bbio_ret)
5268 {
5269         struct extent_map *em;
5270         struct map_lookup *map;
5271         struct btrfs_bio *bbio;
5272         u64 offset;
5273         u64 stripe_nr;
5274         u64 stripe_nr_end;
5275         u64 stripe_end_offset;
5276         u64 stripe_cnt;
5277         u64 stripe_len;
5278         u64 stripe_offset;
5279         u64 num_stripes;
5280         u32 stripe_index;
5281         u32 factor = 0;
5282         u32 sub_stripes = 0;
5283         u64 stripes_per_dev = 0;
5284         u32 remaining_stripes = 0;
5285         u32 last_stripe = 0;
5286         int ret = 0;
5287         int i;
5288
5289         /* discard always return a bbio */
5290         ASSERT(bbio_ret);
5291
5292         em = get_chunk_map(fs_info, logical, length);
5293         if (IS_ERR(em))
5294                 return PTR_ERR(em);
5295
5296         map = em->map_lookup;
5297         /* we don't discard raid56 yet */
5298         if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
5299                 ret = -EOPNOTSUPP;
5300                 goto out;
5301         }
5302
5303         offset = logical - em->start;
5304         length = min_t(u64, em->len - offset, length);
5305
5306         stripe_len = map->stripe_len;
5307         /*
5308          * stripe_nr counts the total number of stripes we have to stride
5309          * to get to this block
5310          */
5311         stripe_nr = div64_u64(offset, stripe_len);
5312
5313         /* stripe_offset is the offset of this block in its stripe */
5314         stripe_offset = offset - stripe_nr * stripe_len;
5315
5316         stripe_nr_end = round_up(offset + length, map->stripe_len);
5317         stripe_nr_end = div64_u64(stripe_nr_end, map->stripe_len);
5318         stripe_cnt = stripe_nr_end - stripe_nr;
5319         stripe_end_offset = stripe_nr_end * map->stripe_len -
5320                             (offset + length);
5321         /*
5322          * after this, stripe_nr is the number of stripes on this
5323          * device we have to walk to find the data, and stripe_index is
5324          * the number of our device in the stripe array
5325          */
5326         num_stripes = 1;
5327         stripe_index = 0;
5328         if (map->type & (BTRFS_BLOCK_GROUP_RAID0 |
5329                          BTRFS_BLOCK_GROUP_RAID10)) {
5330                 if (map->type & BTRFS_BLOCK_GROUP_RAID0)
5331                         sub_stripes = 1;
5332                 else
5333                         sub_stripes = map->sub_stripes;
5334
5335                 factor = map->num_stripes / sub_stripes;
5336                 num_stripes = min_t(u64, map->num_stripes,
5337                                     sub_stripes * stripe_cnt);
5338                 stripe_nr = div_u64_rem(stripe_nr, factor, &stripe_index);
5339                 stripe_index *= sub_stripes;
5340                 stripes_per_dev = div_u64_rem(stripe_cnt, factor,
5341                                               &remaining_stripes);
5342                 div_u64_rem(stripe_nr_end - 1, factor, &last_stripe);
5343                 last_stripe *= sub_stripes;
5344         } else if (map->type & (BTRFS_BLOCK_GROUP_RAID1 |
5345                                 BTRFS_BLOCK_GROUP_DUP)) {
5346                 num_stripes = map->num_stripes;
5347         } else {
5348                 stripe_nr = div_u64_rem(stripe_nr, map->num_stripes,
5349                                         &stripe_index);
5350         }
5351
5352         bbio = alloc_btrfs_bio(num_stripes, 0);
5353         if (!bbio) {
5354                 ret = -ENOMEM;
5355                 goto out;
5356         }
5357
5358         for (i = 0; i < num_stripes; i++) {
5359                 bbio->stripes[i].physical =
5360                         map->stripes[stripe_index].physical +
5361                         stripe_offset + stripe_nr * map->stripe_len;
5362                 bbio->stripes[i].dev = map->stripes[stripe_index].dev;
5363
5364                 if (map->type & (BTRFS_BLOCK_GROUP_RAID0 |
5365                                  BTRFS_BLOCK_GROUP_RAID10)) {
5366                         bbio->stripes[i].length = stripes_per_dev *
5367                                 map->stripe_len;
5368
5369                         if (i / sub_stripes < remaining_stripes)
5370                                 bbio->stripes[i].length +=
5371                                         map->stripe_len;
5372
5373                         /*
5374                          * Special for the first stripe and
5375                          * the last stripe:
5376                          *
5377                          * |-------|...|-------|
5378                          *     |----------|
5379                          *    off     end_off
5380                          */
5381                         if (i < sub_stripes)
5382                                 bbio->stripes[i].length -=
5383                                         stripe_offset;
5384
5385                         if (stripe_index >= last_stripe &&
5386                             stripe_index <= (last_stripe +
5387                                              sub_stripes - 1))
5388                                 bbio->stripes[i].length -=
5389                                         stripe_end_offset;
5390
5391                         if (i == sub_stripes - 1)
5392                                 stripe_offset = 0;
5393                 } else {
5394                         bbio->stripes[i].length = length;
5395                 }
5396
5397                 stripe_index++;
5398                 if (stripe_index == map->num_stripes) {
5399                         stripe_index = 0;
5400                         stripe_nr++;
5401                 }
5402         }
5403
5404         *bbio_ret = bbio;
5405         bbio->map_type = map->type;
5406         bbio->num_stripes = num_stripes;
5407 out:
5408         free_extent_map(em);
5409         return ret;
5410 }
5411
5412 /*
5413  * In dev-replace case, for repair case (that's the only case where the mirror
5414  * is selected explicitly when calling btrfs_map_block), blocks left of the
5415  * left cursor can also be read from the target drive.
5416  *
5417  * For REQ_GET_READ_MIRRORS, the target drive is added as the last one to the
5418  * array of stripes.
5419  * For READ, it also needs to be supported using the same mirror number.
5420  *
5421  * If the requested block is not left of the left cursor, EIO is returned. This
5422  * can happen because btrfs_num_copies() returns one more in the dev-replace
5423  * case.
5424  */
5425 static int get_extra_mirror_from_replace(struct btrfs_fs_info *fs_info,
5426                                          u64 logical, u64 length,
5427                                          u64 srcdev_devid, int *mirror_num,
5428                                          u64 *physical)
5429 {
5430         struct btrfs_bio *bbio = NULL;
5431         int num_stripes;
5432         int index_srcdev = 0;
5433         int found = 0;
5434         u64 physical_of_found = 0;
5435         int i;
5436         int ret = 0;
5437
5438         ret = __btrfs_map_block(fs_info, BTRFS_MAP_GET_READ_MIRRORS,
5439                                 logical, &length, &bbio, 0, 0);
5440         if (ret) {
5441                 ASSERT(bbio == NULL);
5442                 return ret;
5443         }
5444
5445         num_stripes = bbio->num_stripes;
5446         if (*mirror_num > num_stripes) {
5447                 /*
5448                  * BTRFS_MAP_GET_READ_MIRRORS does not contain this mirror,
5449                  * that means that the requested area is not left of the left
5450                  * cursor
5451                  */
5452                 btrfs_put_bbio(bbio);
5453                 return -EIO;
5454         }
5455
5456         /*
5457          * process the rest of the function using the mirror_num of the source
5458          * drive. Therefore look it up first.  At the end, patch the device
5459          * pointer to the one of the target drive.
5460          */
5461         for (i = 0; i < num_stripes; i++) {
5462                 if (bbio->stripes[i].dev->devid != srcdev_devid)
5463                         continue;
5464
5465                 /*
5466                  * In case of DUP, in order to keep it simple, only add the
5467                  * mirror with the lowest physical address
5468                  */
5469                 if (found &&
5470                     physical_of_found <= bbio->stripes[i].physical)
5471                         continue;
5472
5473                 index_srcdev = i;
5474                 found = 1;
5475                 physical_of_found = bbio->stripes[i].physical;
5476         }
5477
5478         btrfs_put_bbio(bbio);
5479
5480         ASSERT(found);
5481         if (!found)
5482                 return -EIO;
5483
5484         *mirror_num = index_srcdev + 1;
5485         *physical = physical_of_found;
5486         return ret;
5487 }
5488
5489 static void handle_ops_on_dev_replace(enum btrfs_map_op op,
5490                                       struct btrfs_bio **bbio_ret,
5491                                       struct btrfs_dev_replace *dev_replace,
5492                                       int *num_stripes_ret, int *max_errors_ret)
5493 {
5494         struct btrfs_bio *bbio = *bbio_ret;
5495         u64 srcdev_devid = dev_replace->srcdev->devid;
5496         int tgtdev_indexes = 0;
5497         int num_stripes = *num_stripes_ret;
5498         int max_errors = *max_errors_ret;
5499         int i;
5500
5501         if (op == BTRFS_MAP_WRITE) {
5502                 int index_where_to_add;
5503
5504                 /*
5505                  * duplicate the write operations while the dev replace
5506                  * procedure is running. Since the copying of the old disk to
5507                  * the new disk takes place at run time while the filesystem is
5508                  * mounted writable, the regular write operations to the old
5509                  * disk have to be duplicated to go to the new disk as well.
5510                  *
5511                  * Note that device->missing is handled by the caller, and that
5512                  * the write to the old disk is already set up in the stripes
5513                  * array.
5514                  */
5515                 index_where_to_add = num_stripes;
5516                 for (i = 0; i < num_stripes; i++) {
5517                         if (bbio->stripes[i].dev->devid == srcdev_devid) {
5518                                 /* write to new disk, too */
5519                                 struct btrfs_bio_stripe *new =
5520                                         bbio->stripes + index_where_to_add;
5521                                 struct btrfs_bio_stripe *old =
5522                                         bbio->stripes + i;
5523
5524                                 new->physical = old->physical;
5525                                 new->length = old->length;
5526                                 new->dev = dev_replace->tgtdev;
5527                                 bbio->tgtdev_map[i] = index_where_to_add;
5528                                 index_where_to_add++;
5529                                 max_errors++;
5530                                 tgtdev_indexes++;
5531                         }
5532                 }
5533                 num_stripes = index_where_to_add;
5534         } else if (op == BTRFS_MAP_GET_READ_MIRRORS) {
5535                 int index_srcdev = 0;
5536                 int found = 0;
5537                 u64 physical_of_found = 0;
5538
5539                 /*
5540                  * During the dev-replace procedure, the target drive can also
5541                  * be used to read data in case it is needed to repair a corrupt
5542                  * block elsewhere. This is possible if the requested area is
5543                  * left of the left cursor. In this area, the target drive is a
5544                  * full copy of the source drive.
5545                  */
5546                 for (i = 0; i < num_stripes; i++) {
5547                         if (bbio->stripes[i].dev->devid == srcdev_devid) {
5548                                 /*
5549                                  * In case of DUP, in order to keep it simple,
5550                                  * only add the mirror with the lowest physical
5551                                  * address
5552                                  */
5553                                 if (found &&
5554                                     physical_of_found <=
5555                                      bbio->stripes[i].physical)
5556                                         continue;
5557                                 index_srcdev = i;
5558                                 found = 1;
5559                                 physical_of_found = bbio->stripes[i].physical;
5560                         }
5561                 }
5562                 if (found) {
5563                         struct btrfs_bio_stripe *tgtdev_stripe =
5564                                 bbio->stripes + num_stripes;
5565
5566                         tgtdev_stripe->physical = physical_of_found;
5567                         tgtdev_stripe->length =
5568                                 bbio->stripes[index_srcdev].length;
5569                         tgtdev_stripe->dev = dev_replace->tgtdev;
5570                         bbio->tgtdev_map[index_srcdev] = num_stripes;
5571
5572                         tgtdev_indexes++;
5573                         num_stripes++;
5574                 }
5575         }
5576
5577         *num_stripes_ret = num_stripes;
5578         *max_errors_ret = max_errors;
5579         bbio->num_tgtdevs = tgtdev_indexes;
5580         *bbio_ret = bbio;
5581 }
5582
5583 static bool need_full_stripe(enum btrfs_map_op op)
5584 {
5585         return (op == BTRFS_MAP_WRITE || op == BTRFS_MAP_GET_READ_MIRRORS);
5586 }
5587
5588 static int __btrfs_map_block(struct btrfs_fs_info *fs_info,
5589                              enum btrfs_map_op op,
5590                              u64 logical, u64 *length,
5591                              struct btrfs_bio **bbio_ret,
5592                              int mirror_num, int need_raid_map)
5593 {
5594         struct extent_map *em;
5595         struct map_lookup *map;
5596         u64 offset;
5597         u64 stripe_offset;
5598         u64 stripe_nr;
5599         u64 stripe_len;
5600         u32 stripe_index;
5601         int i;
5602         int ret = 0;
5603         int num_stripes;
5604         int max_errors = 0;
5605         int tgtdev_indexes = 0;
5606         struct btrfs_bio *bbio = NULL;
5607         struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
5608         int dev_replace_is_ongoing = 0;
5609         int num_alloc_stripes;
5610         int patch_the_first_stripe_for_dev_replace = 0;
5611         u64 physical_to_patch_in_first_stripe = 0;
5612         u64 raid56_full_stripe_start = (u64)-1;
5613
5614         if (op == BTRFS_MAP_DISCARD)
5615                 return __btrfs_map_block_for_discard(fs_info, logical,
5616                                                      *length, bbio_ret);
5617
5618         em = get_chunk_map(fs_info, logical, *length);
5619         if (IS_ERR(em))
5620                 return PTR_ERR(em);
5621
5622         map = em->map_lookup;
5623         offset = logical - em->start;
5624
5625         stripe_len = map->stripe_len;
5626         stripe_nr = offset;
5627         /*
5628          * stripe_nr counts the total number of stripes we have to stride
5629          * to get to this block
5630          */
5631         stripe_nr = div64_u64(stripe_nr, stripe_len);
5632
5633         stripe_offset = stripe_nr * stripe_len;
5634         if (offset < stripe_offset) {
5635                 btrfs_crit(fs_info,
5636                            "stripe math has gone wrong, stripe_offset=%llu, offset=%llu, start=%llu, logical=%llu, stripe_len=%llu",
5637                            stripe_offset, offset, em->start, logical,
5638                            stripe_len);
5639                 free_extent_map(em);
5640                 return -EINVAL;
5641         }
5642
5643         /* stripe_offset is the offset of this block in its stripe*/
5644         stripe_offset = offset - stripe_offset;
5645
5646         /* if we're here for raid56, we need to know the stripe aligned start */
5647         if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
5648                 unsigned long full_stripe_len = stripe_len * nr_data_stripes(map);
5649                 raid56_full_stripe_start = offset;
5650
5651                 /* allow a write of a full stripe, but make sure we don't
5652                  * allow straddling of stripes
5653                  */
5654                 raid56_full_stripe_start = div64_u64(raid56_full_stripe_start,
5655                                 full_stripe_len);
5656                 raid56_full_stripe_start *= full_stripe_len;
5657         }
5658
5659         if (map->type & BTRFS_BLOCK_GROUP_PROFILE_MASK) {
5660                 u64 max_len;
5661                 /* For writes to RAID[56], allow a full stripeset across all disks.
5662                    For other RAID types and for RAID[56] reads, just allow a single
5663                    stripe (on a single disk). */
5664                 if ((map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) &&
5665                     (op == BTRFS_MAP_WRITE)) {
5666                         max_len = stripe_len * nr_data_stripes(map) -
5667                                 (offset - raid56_full_stripe_start);
5668                 } else {
5669                         /* we limit the length of each bio to what fits in a stripe */
5670                         max_len = stripe_len - stripe_offset;
5671                 }
5672                 *length = min_t(u64, em->len - offset, max_len);
5673         } else {
5674                 *length = em->len - offset;
5675         }
5676
5677         /* This is for when we're called from btrfs_merge_bio_hook() and all
5678            it cares about is the length */
5679         if (!bbio_ret)
5680                 goto out;
5681
5682         btrfs_dev_replace_lock(dev_replace, 0);
5683         dev_replace_is_ongoing = btrfs_dev_replace_is_ongoing(dev_replace);
5684         if (!dev_replace_is_ongoing)
5685                 btrfs_dev_replace_unlock(dev_replace, 0);
5686         else
5687                 btrfs_dev_replace_set_lock_blocking(dev_replace);
5688
5689         if (dev_replace_is_ongoing && mirror_num == map->num_stripes + 1 &&
5690             !need_full_stripe(op) && dev_replace->tgtdev != NULL) {
5691                 ret = get_extra_mirror_from_replace(fs_info, logical, *length,
5692                                                     dev_replace->srcdev->devid,
5693                                                     &mirror_num,
5694                                             &physical_to_patch_in_first_stripe);
5695                 if (ret)
5696                         goto out;
5697                 else
5698                         patch_the_first_stripe_for_dev_replace = 1;
5699         } else if (mirror_num > map->num_stripes) {
5700                 mirror_num = 0;
5701         }
5702
5703         num_stripes = 1;
5704         stripe_index = 0;
5705         if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
5706                 stripe_nr = div_u64_rem(stripe_nr, map->num_stripes,
5707                                 &stripe_index);
5708                 if (!need_full_stripe(op))
5709                         mirror_num = 1;
5710         } else if (map->type & BTRFS_BLOCK_GROUP_RAID1) {
5711                 if (need_full_stripe(op))
5712                         num_stripes = map->num_stripes;
5713                 else if (mirror_num)
5714                         stripe_index = mirror_num - 1;
5715                 else {
5716                         stripe_index = find_live_mirror(fs_info, map, 0,
5717                                             map->num_stripes,
5718                                             current->pid % map->num_stripes,
5719                                             dev_replace_is_ongoing);
5720                         mirror_num = stripe_index + 1;
5721                 }
5722
5723         } else if (map->type & BTRFS_BLOCK_GROUP_DUP) {
5724                 if (need_full_stripe(op)) {
5725                         num_stripes = map->num_stripes;
5726                 } else if (mirror_num) {
5727                         stripe_index = mirror_num - 1;
5728                 } else {
5729                         mirror_num = 1;
5730                 }
5731
5732         } else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
5733                 u32 factor = map->num_stripes / map->sub_stripes;
5734
5735                 stripe_nr = div_u64_rem(stripe_nr, factor, &stripe_index);
5736                 stripe_index *= map->sub_stripes;
5737
5738                 if (need_full_stripe(op))
5739                         num_stripes = map->sub_stripes;
5740                 else if (mirror_num)
5741                         stripe_index += mirror_num - 1;
5742                 else {
5743                         int old_stripe_index = stripe_index;
5744                         stripe_index = find_live_mirror(fs_info, map,
5745                                               stripe_index,
5746                                               map->sub_stripes, stripe_index +
5747                                               current->pid % map->sub_stripes,
5748                                               dev_replace_is_ongoing);
5749                         mirror_num = stripe_index - old_stripe_index + 1;
5750                 }
5751
5752         } else if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
5753                 if (need_raid_map && (need_full_stripe(op) || mirror_num > 1)) {
5754                         /* push stripe_nr back to the start of the full stripe */
5755                         stripe_nr = div64_u64(raid56_full_stripe_start,
5756                                         stripe_len * nr_data_stripes(map));
5757
5758                         /* RAID[56] write or recovery. Return all stripes */
5759                         num_stripes = map->num_stripes;
5760                         max_errors = nr_parity_stripes(map);
5761
5762                         *length = map->stripe_len;
5763                         stripe_index = 0;
5764                         stripe_offset = 0;
5765                 } else {
5766                         /*
5767                          * Mirror #0 or #1 means the original data block.
5768                          * Mirror #2 is RAID5 parity block.
5769                          * Mirror #3 is RAID6 Q block.
5770                          */
5771                         stripe_nr = div_u64_rem(stripe_nr,
5772                                         nr_data_stripes(map), &stripe_index);
5773                         if (mirror_num > 1)
5774                                 stripe_index = nr_data_stripes(map) +
5775                                                 mirror_num - 2;
5776
5777                         /* We distribute the parity blocks across stripes */
5778                         div_u64_rem(stripe_nr + stripe_index, map->num_stripes,
5779                                         &stripe_index);
5780                         if (!need_full_stripe(op) && mirror_num <= 1)
5781                                 mirror_num = 1;
5782                 }
5783         } else {
5784                 /*
5785                  * after this, stripe_nr is the number of stripes on this
5786                  * device we have to walk to find the data, and stripe_index is
5787                  * the number of our device in the stripe array
5788                  */
5789                 stripe_nr = div_u64_rem(stripe_nr, map->num_stripes,
5790                                 &stripe_index);
5791                 mirror_num = stripe_index + 1;
5792         }
5793         if (stripe_index >= map->num_stripes) {
5794                 btrfs_crit(fs_info,
5795                            "stripe index math went horribly wrong, got stripe_index=%u, num_stripes=%u",
5796                            stripe_index, map->num_stripes);
5797                 ret = -EINVAL;
5798                 goto out;
5799         }
5800
5801         num_alloc_stripes = num_stripes;
5802         if (dev_replace_is_ongoing && dev_replace->tgtdev != NULL) {
5803                 if (op == BTRFS_MAP_WRITE)
5804                         num_alloc_stripes <<= 1;
5805                 if (op == BTRFS_MAP_GET_READ_MIRRORS)
5806                         num_alloc_stripes++;
5807                 tgtdev_indexes = num_stripes;
5808         }
5809
5810         bbio = alloc_btrfs_bio(num_alloc_stripes, tgtdev_indexes);
5811         if (!bbio) {
5812                 ret = -ENOMEM;
5813                 goto out;
5814         }
5815         if (dev_replace_is_ongoing && dev_replace->tgtdev != NULL)
5816                 bbio->tgtdev_map = (int *)(bbio->stripes + num_alloc_stripes);
5817
5818         /* build raid_map */
5819         if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK && need_raid_map &&
5820             (need_full_stripe(op) || mirror_num > 1)) {
5821                 u64 tmp;
5822                 unsigned rot;
5823
5824                 bbio->raid_map = (u64 *)((void *)bbio->stripes +
5825                                  sizeof(struct btrfs_bio_stripe) *
5826                                  num_alloc_stripes +
5827                                  sizeof(int) * tgtdev_indexes);
5828
5829                 /* Work out the disk rotation on this stripe-set */
5830                 div_u64_rem(stripe_nr, num_stripes, &rot);
5831
5832                 /* Fill in the logical address of each stripe */
5833                 tmp = stripe_nr * nr_data_stripes(map);
5834                 for (i = 0; i < nr_data_stripes(map); i++)
5835                         bbio->raid_map[(i+rot) % num_stripes] =
5836                                 em->start + (tmp + i) * map->stripe_len;
5837
5838                 bbio->raid_map[(i+rot) % map->num_stripes] = RAID5_P_STRIPE;
5839                 if (map->type & BTRFS_BLOCK_GROUP_RAID6)
5840                         bbio->raid_map[(i+rot+1) % num_stripes] =
5841                                 RAID6_Q_STRIPE;
5842         }
5843
5844
5845         for (i = 0; i < num_stripes; i++) {
5846                 bbio->stripes[i].physical =
5847                         map->stripes[stripe_index].physical +
5848                         stripe_offset +
5849                         stripe_nr * map->stripe_len;
5850                 bbio->stripes[i].dev =
5851                         map->stripes[stripe_index].dev;
5852                 stripe_index++;
5853         }
5854
5855         if (need_full_stripe(op))
5856                 max_errors = btrfs_chunk_max_errors(map);
5857
5858         if (bbio->raid_map)
5859                 sort_parity_stripes(bbio, num_stripes);
5860
5861         if (dev_replace_is_ongoing && dev_replace->tgtdev != NULL &&
5862             need_full_stripe(op)) {
5863                 handle_ops_on_dev_replace(op, &bbio, dev_replace, &num_stripes,
5864                                           &max_errors);
5865         }
5866
5867         *bbio_ret = bbio;
5868         bbio->map_type = map->type;
5869         bbio->num_stripes = num_stripes;
5870         bbio->max_errors = max_errors;
5871         bbio->mirror_num = mirror_num;
5872
5873         /*
5874          * this is the case that REQ_READ && dev_replace_is_ongoing &&
5875          * mirror_num == num_stripes + 1 && dev_replace target drive is
5876          * available as a mirror
5877          */
5878         if (patch_the_first_stripe_for_dev_replace && num_stripes > 0) {
5879                 WARN_ON(num_stripes > 1);
5880                 bbio->stripes[0].dev = dev_replace->tgtdev;
5881                 bbio->stripes[0].physical = physical_to_patch_in_first_stripe;
5882                 bbio->mirror_num = map->num_stripes + 1;
5883         }
5884 out:
5885         if (dev_replace_is_ongoing) {
5886                 btrfs_dev_replace_clear_lock_blocking(dev_replace);
5887                 btrfs_dev_replace_unlock(dev_replace, 0);
5888         }
5889         free_extent_map(em);
5890         return ret;
5891 }
5892
5893 int btrfs_map_block(struct btrfs_fs_info *fs_info, enum btrfs_map_op op,
5894                       u64 logical, u64 *length,
5895                       struct btrfs_bio **bbio_ret, int mirror_num)
5896 {
5897         return __btrfs_map_block(fs_info, op, logical, length, bbio_ret,
5898                                  mirror_num, 0);
5899 }
5900
5901 /* For Scrub/replace */
5902 int btrfs_map_sblock(struct btrfs_fs_info *fs_info, enum btrfs_map_op op,
5903                      u64 logical, u64 *length,
5904                      struct btrfs_bio **bbio_ret)
5905 {
5906         return __btrfs_map_block(fs_info, op, logical, length, bbio_ret, 0, 1);
5907 }
5908
5909 int btrfs_rmap_block(struct btrfs_fs_info *fs_info,
5910                      u64 chunk_start, u64 physical, u64 devid,
5911                      u64 **logical, int *naddrs, int *stripe_len)
5912 {
5913         struct extent_map *em;
5914         struct map_lookup *map;
5915         u64 *buf;
5916         u64 bytenr;
5917         u64 length;
5918         u64 stripe_nr;
5919         u64 rmap_len;
5920         int i, j, nr = 0;
5921
5922         em = get_chunk_map(fs_info, chunk_start, 1);
5923         if (IS_ERR(em))
5924                 return -EIO;
5925
5926         map = em->map_lookup;
5927         length = em->len;
5928         rmap_len = map->stripe_len;
5929
5930         if (map->type & BTRFS_BLOCK_GROUP_RAID10)
5931                 length = div_u64(length, map->num_stripes / map->sub_stripes);
5932         else if (map->type & BTRFS_BLOCK_GROUP_RAID0)
5933                 length = div_u64(length, map->num_stripes);
5934         else if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
5935                 length = div_u64(length, nr_data_stripes(map));
5936                 rmap_len = map->stripe_len * nr_data_stripes(map);
5937         }
5938
5939         buf = kcalloc(map->num_stripes, sizeof(u64), GFP_NOFS);
5940         BUG_ON(!buf); /* -ENOMEM */
5941
5942         for (i = 0; i < map->num_stripes; i++) {
5943                 if (devid && map->stripes[i].dev->devid != devid)
5944                         continue;
5945                 if (map->stripes[i].physical > physical ||
5946                     map->stripes[i].physical + length <= physical)
5947                         continue;
5948
5949                 stripe_nr = physical - map->stripes[i].physical;
5950                 stripe_nr = div64_u64(stripe_nr, map->stripe_len);
5951
5952                 if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
5953                         stripe_nr = stripe_nr * map->num_stripes + i;
5954                         stripe_nr = div_u64(stripe_nr, map->sub_stripes);
5955                 } else if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
5956                         stripe_nr = stripe_nr * map->num_stripes + i;
5957                 } /* else if RAID[56], multiply by nr_data_stripes().
5958                    * Alternatively, just use rmap_len below instead of
5959                    * map->stripe_len */
5960
5961                 bytenr = chunk_start + stripe_nr * rmap_len;
5962                 WARN_ON(nr >= map->num_stripes);
5963                 for (j = 0; j < nr; j++) {
5964                         if (buf[j] == bytenr)
5965                                 break;
5966                 }
5967                 if (j == nr) {
5968                         WARN_ON(nr >= map->num_stripes);
5969                         buf[nr++] = bytenr;
5970                 }
5971         }
5972
5973         *logical = buf;
5974         *naddrs = nr;
5975         *stripe_len = rmap_len;
5976
5977         free_extent_map(em);
5978         return 0;
5979 }
5980
5981 static inline void btrfs_end_bbio(struct btrfs_bio *bbio, struct bio *bio)
5982 {
5983         bio->bi_private = bbio->private;
5984         bio->bi_end_io = bbio->end_io;
5985         bio_endio(bio);
5986
5987         btrfs_put_bbio(bbio);
5988 }
5989
5990 static void btrfs_end_bio(struct bio *bio)
5991 {
5992         struct btrfs_bio *bbio = bio->bi_private;
5993         int is_orig_bio = 0;
5994
5995         if (bio->bi_status) {
5996                 atomic_inc(&bbio->error);
5997                 if (bio->bi_status == BLK_STS_IOERR ||
5998                     bio->bi_status == BLK_STS_TARGET) {
5999                         unsigned int stripe_index =
6000                                 btrfs_io_bio(bio)->stripe_index;
6001                         struct btrfs_device *dev;
6002
6003                         BUG_ON(stripe_index >= bbio->num_stripes);
6004                         dev = bbio->stripes[stripe_index].dev;
6005                         if (dev->bdev) {
6006                                 if (bio_op(bio) == REQ_OP_WRITE)
6007                                         btrfs_dev_stat_inc(dev,
6008                                                 BTRFS_DEV_STAT_WRITE_ERRS);
6009                                 else
6010                                         btrfs_dev_stat_inc(dev,
6011                                                 BTRFS_DEV_STAT_READ_ERRS);
6012                                 if (bio->bi_opf & REQ_PREFLUSH)
6013                                         btrfs_dev_stat_inc(dev,
6014                                                 BTRFS_DEV_STAT_FLUSH_ERRS);
6015                                 btrfs_dev_stat_print_on_error(dev);
6016                         }
6017                 }
6018         }
6019
6020         if (bio == bbio->orig_bio)
6021                 is_orig_bio = 1;
6022
6023         btrfs_bio_counter_dec(bbio->fs_info);
6024
6025         if (atomic_dec_and_test(&bbio->stripes_pending)) {
6026                 if (!is_orig_bio) {
6027                         bio_put(bio);
6028                         bio = bbio->orig_bio;
6029                 }
6030
6031                 btrfs_io_bio(bio)->mirror_num = bbio->mirror_num;
6032                 /* only send an error to the higher layers if it is
6033                  * beyond the tolerance of the btrfs bio
6034                  */
6035                 if (atomic_read(&bbio->error) > bbio->max_errors) {
6036                         bio->bi_status = BLK_STS_IOERR;
6037                 } else {
6038                         /*
6039                          * this bio is actually up to date, we didn't
6040                          * go over the max number of errors
6041                          */
6042                         bio->bi_status = BLK_STS_OK;
6043                 }
6044
6045                 btrfs_end_bbio(bbio, bio);
6046         } else if (!is_orig_bio) {
6047                 bio_put(bio);
6048         }
6049 }
6050
6051 /*
6052  * see run_scheduled_bios for a description of why bios are collected for
6053  * async submit.
6054  *
6055  * This will add one bio to the pending list for a device and make sure
6056  * the work struct is scheduled.
6057  */
6058 static noinline void btrfs_schedule_bio(struct btrfs_device *device,
6059                                         struct bio *bio)
6060 {
6061         struct btrfs_fs_info *fs_info = device->fs_info;
6062         int should_queue = 1;
6063         struct btrfs_pending_bios *pending_bios;
6064
6065         if (device->missing || !device->bdev) {
6066                 bio_io_error(bio);
6067                 return;
6068         }
6069
6070         /* don't bother with additional async steps for reads, right now */
6071         if (bio_op(bio) == REQ_OP_READ) {
6072                 bio_get(bio);
6073                 btrfsic_submit_bio(bio);
6074                 bio_put(bio);
6075                 return;
6076         }
6077
6078         WARN_ON(bio->bi_next);
6079         bio->bi_next = NULL;
6080
6081         spin_lock(&device->io_lock);
6082         if (op_is_sync(bio->bi_opf))
6083                 pending_bios = &device->pending_sync_bios;
6084         else
6085                 pending_bios = &device->pending_bios;
6086
6087         if (pending_bios->tail)
6088                 pending_bios->tail->bi_next = bio;
6089
6090         pending_bios->tail = bio;
6091         if (!pending_bios->head)
6092                 pending_bios->head = bio;
6093         if (device->running_pending)
6094                 should_queue = 0;
6095
6096         spin_unlock(&device->io_lock);
6097
6098         if (should_queue)
6099                 btrfs_queue_work(fs_info->submit_workers, &device->work);
6100 }
6101
6102 static void submit_stripe_bio(struct btrfs_bio *bbio, struct bio *bio,
6103                               u64 physical, int dev_nr, int async)
6104 {
6105         struct btrfs_device *dev = bbio->stripes[dev_nr].dev;
6106         struct btrfs_fs_info *fs_info = bbio->fs_info;
6107
6108         bio->bi_private = bbio;
6109         btrfs_io_bio(bio)->stripe_index = dev_nr;
6110         bio->bi_end_io = btrfs_end_bio;
6111         bio->bi_iter.bi_sector = physical >> 9;
6112 #ifdef DEBUG
6113         {
6114                 struct rcu_string *name;
6115
6116                 rcu_read_lock();
6117                 name = rcu_dereference(dev->name);
6118                 btrfs_debug(fs_info,
6119                         "btrfs_map_bio: rw %d 0x%x, sector=%llu, dev=%lu (%s id %llu), size=%u",
6120                         bio_op(bio), bio->bi_opf,
6121                         (u64)bio->bi_iter.bi_sector,
6122                         (u_long)dev->bdev->bd_dev, name->str, dev->devid,
6123                         bio->bi_iter.bi_size);
6124                 rcu_read_unlock();
6125         }
6126 #endif
6127         bio_set_dev(bio, dev->bdev);
6128
6129         btrfs_bio_counter_inc_noblocked(fs_info);
6130
6131         if (async)
6132                 btrfs_schedule_bio(dev, bio);
6133         else
6134                 btrfsic_submit_bio(bio);
6135 }
6136
6137 static void bbio_error(struct btrfs_bio *bbio, struct bio *bio, u64 logical)
6138 {
6139         atomic_inc(&bbio->error);
6140         if (atomic_dec_and_test(&bbio->stripes_pending)) {
6141                 /* Should be the original bio. */
6142                 WARN_ON(bio != bbio->orig_bio);
6143
6144                 btrfs_io_bio(bio)->mirror_num = bbio->mirror_num;
6145                 bio->bi_iter.bi_sector = logical >> 9;
6146                 if (atomic_read(&bbio->error) > bbio->max_errors)
6147                         bio->bi_status = BLK_STS_IOERR;
6148                 else
6149                         bio->bi_status = BLK_STS_OK;
6150                 btrfs_end_bbio(bbio, bio);
6151         }
6152 }
6153
6154 blk_status_t btrfs_map_bio(struct btrfs_fs_info *fs_info, struct bio *bio,
6155                            int mirror_num, int async_submit)
6156 {
6157         struct btrfs_device *dev;
6158         struct bio *first_bio = bio;
6159         u64 logical = (u64)bio->bi_iter.bi_sector << 9;
6160         u64 length = 0;
6161         u64 map_length;
6162         int ret;
6163         int dev_nr;
6164         int total_devs;
6165         struct btrfs_bio *bbio = NULL;
6166
6167         length = bio->bi_iter.bi_size;
6168         map_length = length;
6169
6170         btrfs_bio_counter_inc_blocked(fs_info);
6171         ret = __btrfs_map_block(fs_info, btrfs_op(bio), logical,
6172                                 &map_length, &bbio, mirror_num, 1);
6173         if (ret) {
6174                 btrfs_bio_counter_dec(fs_info);
6175                 return errno_to_blk_status(ret);
6176         }
6177
6178         total_devs = bbio->num_stripes;
6179         bbio->orig_bio = first_bio;
6180         bbio->private = first_bio->bi_private;
6181         bbio->end_io = first_bio->bi_end_io;
6182         bbio->fs_info = fs_info;
6183         atomic_set(&bbio->stripes_pending, bbio->num_stripes);
6184
6185         if ((bbio->map_type & BTRFS_BLOCK_GROUP_RAID56_MASK) &&
6186             ((bio_op(bio) == REQ_OP_WRITE) || (mirror_num > 1))) {
6187                 /* In this case, map_length has been set to the length of
6188                    a single stripe; not the whole write */
6189                 if (bio_op(bio) == REQ_OP_WRITE) {
6190                         ret = raid56_parity_write(fs_info, bio, bbio,
6191                                                   map_length);
6192                 } else {
6193                         ret = raid56_parity_recover(fs_info, bio, bbio,
6194                                                     map_length, mirror_num, 1);
6195                 }
6196
6197                 btrfs_bio_counter_dec(fs_info);
6198                 return errno_to_blk_status(ret);
6199         }
6200
6201         if (map_length < length) {
6202                 btrfs_crit(fs_info,
6203                            "mapping failed logical %llu bio len %llu len %llu",
6204                            logical, length, map_length);
6205                 BUG();
6206         }
6207
6208         for (dev_nr = 0; dev_nr < total_devs; dev_nr++) {
6209                 dev = bbio->stripes[dev_nr].dev;
6210                 if (!dev || !dev->bdev ||
6211                     (bio_op(first_bio) == REQ_OP_WRITE && !dev->writeable)) {
6212                         bbio_error(bbio, first_bio, logical);
6213                         continue;
6214                 }
6215
6216                 if (dev_nr < total_devs - 1)
6217                         bio = btrfs_bio_clone(first_bio);
6218                 else
6219                         bio = first_bio;
6220
6221                 submit_stripe_bio(bbio, bio, bbio->stripes[dev_nr].physical,
6222                                   dev_nr, async_submit);
6223         }
6224         btrfs_bio_counter_dec(fs_info);
6225         return BLK_STS_OK;
6226 }
6227
6228 struct btrfs_device *btrfs_find_device(struct btrfs_fs_info *fs_info, u64 devid,
6229                                        u8 *uuid, u8 *fsid)
6230 {
6231         struct btrfs_device *device;
6232         struct btrfs_fs_devices *cur_devices;
6233
6234         cur_devices = fs_info->fs_devices;
6235         while (cur_devices) {
6236                 if (!fsid ||
6237                     !memcmp(cur_devices->fsid, fsid, BTRFS_FSID_SIZE)) {
6238                         device = find_device(cur_devices, devid, uuid);
6239                         if (device)
6240                                 return device;
6241                 }
6242                 cur_devices = cur_devices->seed;
6243         }
6244         return NULL;
6245 }
6246
6247 static struct btrfs_device *add_missing_dev(struct btrfs_fs_devices *fs_devices,
6248                                             u64 devid, u8 *dev_uuid)
6249 {
6250         struct btrfs_device *device;
6251
6252         device = btrfs_alloc_device(NULL, &devid, dev_uuid);
6253         if (IS_ERR(device))
6254                 return device;
6255
6256         list_add(&device->dev_list, &fs_devices->devices);
6257         device->fs_devices = fs_devices;
6258         fs_devices->num_devices++;
6259
6260         device->missing = 1;
6261         fs_devices->missing_devices++;
6262
6263         return device;
6264 }
6265
6266 /**
6267  * btrfs_alloc_device - allocate struct btrfs_device
6268  * @fs_info:    used only for generating a new devid, can be NULL if
6269  *              devid is provided (i.e. @devid != NULL).
6270  * @devid:      a pointer to devid for this device.  If NULL a new devid
6271  *              is generated.
6272  * @uuid:       a pointer to UUID for this device.  If NULL a new UUID
6273  *              is generated.
6274  *
6275  * Return: a pointer to a new &struct btrfs_device on success; ERR_PTR()
6276  * on error.  Returned struct is not linked onto any lists and can be
6277  * destroyed with kfree() right away.
6278  */
6279 struct btrfs_device *btrfs_alloc_device(struct btrfs_fs_info *fs_info,
6280                                         const u64 *devid,
6281                                         const u8 *uuid)
6282 {
6283         struct btrfs_device *dev;
6284         u64 tmp;
6285
6286         if (WARN_ON(!devid && !fs_info))
6287                 return ERR_PTR(-EINVAL);
6288
6289         dev = __alloc_device();
6290         if (IS_ERR(dev))
6291                 return dev;
6292
6293         if (devid)
6294                 tmp = *devid;
6295         else {
6296                 int ret;
6297
6298                 ret = find_next_devid(fs_info, &tmp);
6299                 if (ret) {
6300                         bio_put(dev->flush_bio);
6301                         kfree(dev);
6302                         return ERR_PTR(ret);
6303                 }
6304         }
6305         dev->devid = tmp;
6306
6307         if (uuid)
6308                 memcpy(dev->uuid, uuid, BTRFS_UUID_SIZE);
6309         else
6310                 generate_random_uuid(dev->uuid);
6311
6312         btrfs_init_work(&dev->work, btrfs_submit_helper,
6313                         pending_bios_fn, NULL, NULL);
6314
6315         return dev;
6316 }
6317
6318 /* Return -EIO if any error, otherwise return 0. */
6319 static int btrfs_check_chunk_valid(struct btrfs_fs_info *fs_info,
6320                                    struct extent_buffer *leaf,
6321                                    struct btrfs_chunk *chunk, u64 logical)
6322 {
6323         u64 length;
6324         u64 stripe_len;
6325         u16 num_stripes;
6326         u16 sub_stripes;
6327         u64 type;
6328
6329         length = btrfs_chunk_length(leaf, chunk);
6330         stripe_len = btrfs_chunk_stripe_len(leaf, chunk);
6331         num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
6332         sub_stripes = btrfs_chunk_sub_stripes(leaf, chunk);
6333         type = btrfs_chunk_type(leaf, chunk);
6334
6335         if (!num_stripes) {
6336                 btrfs_err(fs_info, "invalid chunk num_stripes: %u",
6337                           num_stripes);
6338                 return -EIO;
6339         }
6340         if (!IS_ALIGNED(logical, fs_info->sectorsize)) {
6341                 btrfs_err(fs_info, "invalid chunk logical %llu", logical);
6342                 return -EIO;
6343         }
6344         if (btrfs_chunk_sector_size(leaf, chunk) != fs_info->sectorsize) {
6345                 btrfs_err(fs_info, "invalid chunk sectorsize %u",
6346                           btrfs_chunk_sector_size(leaf, chunk));
6347                 return -EIO;
6348         }
6349         if (!length || !IS_ALIGNED(length, fs_info->sectorsize)) {
6350                 btrfs_err(fs_info, "invalid chunk length %llu", length);
6351                 return -EIO;
6352         }
6353         if (!is_power_of_2(stripe_len) || stripe_len != BTRFS_STRIPE_LEN) {
6354                 btrfs_err(fs_info, "invalid chunk stripe length: %llu",
6355                           stripe_len);
6356                 return -EIO;
6357         }
6358         if (~(BTRFS_BLOCK_GROUP_TYPE_MASK | BTRFS_BLOCK_GROUP_PROFILE_MASK) &
6359             type) {
6360                 btrfs_err(fs_info, "unrecognized chunk type: %llu",
6361                           ~(BTRFS_BLOCK_GROUP_TYPE_MASK |
6362                             BTRFS_BLOCK_GROUP_PROFILE_MASK) &
6363                           btrfs_chunk_type(leaf, chunk));
6364                 return -EIO;
6365         }
6366         if ((type & BTRFS_BLOCK_GROUP_RAID10 && sub_stripes != 2) ||
6367             (type & BTRFS_BLOCK_GROUP_RAID1 && num_stripes < 1) ||
6368             (type & BTRFS_BLOCK_GROUP_RAID5 && num_stripes < 2) ||
6369             (type & BTRFS_BLOCK_GROUP_RAID6 && num_stripes < 3) ||
6370             (type & BTRFS_BLOCK_GROUP_DUP && num_stripes > 2) ||
6371             ((type & BTRFS_BLOCK_GROUP_PROFILE_MASK) == 0 &&
6372              num_stripes != 1)) {
6373                 btrfs_err(fs_info,
6374                         "invalid num_stripes:sub_stripes %u:%u for profile %llu",
6375                         num_stripes, sub_stripes,
6376                         type & BTRFS_BLOCK_GROUP_PROFILE_MASK);
6377                 return -EIO;
6378         }
6379
6380         return 0;
6381 }
6382
6383 static void btrfs_report_missing_device(struct btrfs_fs_info *fs_info,
6384                                         u64 devid, u8 *uuid, bool error)
6385 {
6386         if (error)
6387                 btrfs_err_rl(fs_info, "devid %llu uuid %pU is missing",
6388                               devid, uuid);
6389         else
6390                 btrfs_warn_rl(fs_info, "devid %llu uuid %pU is missing",
6391                               devid, uuid);
6392 }
6393
6394 static int read_one_chunk(struct btrfs_fs_info *fs_info, struct btrfs_key *key,
6395                           struct extent_buffer *leaf,
6396                           struct btrfs_chunk *chunk)
6397 {
6398         struct btrfs_mapping_tree *map_tree = &fs_info->mapping_tree;
6399         struct map_lookup *map;
6400         struct extent_map *em;
6401         u64 logical;
6402         u64 length;
6403         u64 devid;
6404         u8 uuid[BTRFS_UUID_SIZE];
6405         int num_stripes;
6406         int ret;
6407         int i;
6408
6409         logical = key->offset;
6410         length = btrfs_chunk_length(leaf, chunk);
6411         num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
6412
6413         ret = btrfs_check_chunk_valid(fs_info, leaf, chunk, logical);
6414         if (ret)
6415                 return ret;
6416
6417         read_lock(&map_tree->map_tree.lock);
6418         em = lookup_extent_mapping(&map_tree->map_tree, logical, 1);
6419         read_unlock(&map_tree->map_tree.lock);
6420
6421         /* already mapped? */
6422         if (em && em->start <= logical && em->start + em->len > logical) {
6423                 free_extent_map(em);
6424                 return 0;
6425         } else if (em) {
6426                 free_extent_map(em);
6427         }
6428
6429         em = alloc_extent_map();
6430         if (!em)
6431                 return -ENOMEM;
6432         map = kmalloc(map_lookup_size(num_stripes), GFP_NOFS);
6433         if (!map) {
6434                 free_extent_map(em);
6435                 return -ENOMEM;
6436         }
6437
6438         set_bit(EXTENT_FLAG_FS_MAPPING, &em->flags);
6439         em->map_lookup = map;
6440         em->start = logical;
6441         em->len = length;
6442         em->orig_start = 0;
6443         em->block_start = 0;
6444         em->block_len = em->len;
6445
6446         map->num_stripes = num_stripes;
6447         map->io_width = btrfs_chunk_io_width(leaf, chunk);
6448         map->io_align = btrfs_chunk_io_align(leaf, chunk);
6449         map->stripe_len = btrfs_chunk_stripe_len(leaf, chunk);
6450         map->type = btrfs_chunk_type(leaf, chunk);
6451         map->sub_stripes = btrfs_chunk_sub_stripes(leaf, chunk);
6452         for (i = 0; i < num_stripes; i++) {
6453                 map->stripes[i].physical =
6454                         btrfs_stripe_offset_nr(leaf, chunk, i);
6455                 devid = btrfs_stripe_devid_nr(leaf, chunk, i);
6456                 read_extent_buffer(leaf, uuid, (unsigned long)
6457                                    btrfs_stripe_dev_uuid_nr(chunk, i),
6458                                    BTRFS_UUID_SIZE);
6459                 map->stripes[i].dev = btrfs_find_device(fs_info, devid,
6460                                                         uuid, NULL);
6461                 if (!map->stripes[i].dev &&
6462                     !btrfs_test_opt(fs_info, DEGRADED)) {
6463                         free_extent_map(em);
6464                         btrfs_report_missing_device(fs_info, devid, uuid, true);
6465                         return -ENOENT;
6466                 }
6467                 if (!map->stripes[i].dev) {
6468                         map->stripes[i].dev =
6469                                 add_missing_dev(fs_info->fs_devices, devid,
6470                                                 uuid);
6471                         if (IS_ERR(map->stripes[i].dev)) {
6472                                 free_extent_map(em);
6473                                 btrfs_err(fs_info,
6474                                         "failed to init missing dev %llu: %ld",
6475                                         devid, PTR_ERR(map->stripes[i].dev));
6476                                 return PTR_ERR(map->stripes[i].dev);
6477                         }
6478                         btrfs_report_missing_device(fs_info, devid, uuid, false);
6479                 }
6480                 map->stripes[i].dev->in_fs_metadata = 1;
6481         }
6482
6483         write_lock(&map_tree->map_tree.lock);
6484         ret = add_extent_mapping(&map_tree->map_tree, em, 0);
6485         write_unlock(&map_tree->map_tree.lock);
6486         BUG_ON(ret); /* Tree corruption */
6487         free_extent_map(em);
6488
6489         return 0;
6490 }
6491
6492 static void fill_device_from_item(struct extent_buffer *leaf,
6493                                  struct btrfs_dev_item *dev_item,
6494                                  struct btrfs_device *device)
6495 {
6496         unsigned long ptr;
6497
6498         device->devid = btrfs_device_id(leaf, dev_item);
6499         device->disk_total_bytes = btrfs_device_total_bytes(leaf, dev_item);
6500         device->total_bytes = device->disk_total_bytes;
6501         device->commit_total_bytes = device->disk_total_bytes;
6502         device->bytes_used = btrfs_device_bytes_used(leaf, dev_item);
6503         device->commit_bytes_used = device->bytes_used;
6504         device->type = btrfs_device_type(leaf, dev_item);
6505         device->io_align = btrfs_device_io_align(leaf, dev_item);
6506         device->io_width = btrfs_device_io_width(leaf, dev_item);
6507         device->sector_size = btrfs_device_sector_size(leaf, dev_item);
6508         WARN_ON(device->devid == BTRFS_DEV_REPLACE_DEVID);
6509         device->is_tgtdev_for_dev_replace = 0;
6510
6511         ptr = btrfs_device_uuid(dev_item);
6512         read_extent_buffer(leaf, device->uuid, ptr, BTRFS_UUID_SIZE);
6513 }
6514
6515 static struct btrfs_fs_devices *open_seed_devices(struct btrfs_fs_info *fs_info,
6516                                                   u8 *fsid)
6517 {
6518         struct btrfs_fs_devices *fs_devices;
6519         int ret;
6520
6521         BUG_ON(!mutex_is_locked(&uuid_mutex));
6522         ASSERT(fsid);
6523
6524         fs_devices = fs_info->fs_devices->seed;
6525         while (fs_devices) {
6526                 if (!memcmp(fs_devices->fsid, fsid, BTRFS_FSID_SIZE))
6527                         return fs_devices;
6528
6529                 fs_devices = fs_devices->seed;
6530         }
6531
6532         fs_devices = find_fsid(fsid);
6533         if (!fs_devices) {
6534                 if (!btrfs_test_opt(fs_info, DEGRADED))
6535                         return ERR_PTR(-ENOENT);
6536
6537                 fs_devices = alloc_fs_devices(fsid);
6538                 if (IS_ERR(fs_devices))
6539                         return fs_devices;
6540
6541                 fs_devices->seeding = 1;
6542                 fs_devices->opened = 1;
6543                 return fs_devices;
6544         }
6545
6546         fs_devices = clone_fs_devices(fs_devices);
6547         if (IS_ERR(fs_devices))
6548                 return fs_devices;
6549
6550         ret = __btrfs_open_devices(fs_devices, FMODE_READ,
6551                                    fs_info->bdev_holder);
6552         if (ret) {
6553                 free_fs_devices(fs_devices);
6554                 fs_devices = ERR_PTR(ret);
6555                 goto out;
6556         }
6557
6558         if (!fs_devices->seeding) {
6559                 __btrfs_close_devices(fs_devices);
6560                 free_fs_devices(fs_devices);
6561                 fs_devices = ERR_PTR(-EINVAL);
6562                 goto out;
6563         }
6564
6565         fs_devices->seed = fs_info->fs_devices->seed;
6566         fs_info->fs_devices->seed = fs_devices;
6567 out:
6568         return fs_devices;
6569 }
6570
6571 static int read_one_dev(struct btrfs_fs_info *fs_info,
6572                         struct extent_buffer *leaf,
6573                         struct btrfs_dev_item *dev_item)
6574 {
6575         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
6576         struct btrfs_device *device;
6577         u64 devid;
6578         int ret;
6579         u8 fs_uuid[BTRFS_FSID_SIZE];
6580         u8 dev_uuid[BTRFS_UUID_SIZE];
6581
6582         devid = btrfs_device_id(leaf, dev_item);
6583         read_extent_buffer(leaf, dev_uuid, btrfs_device_uuid(dev_item),
6584                            BTRFS_UUID_SIZE);
6585         read_extent_buffer(leaf, fs_uuid, btrfs_device_fsid(dev_item),
6586                            BTRFS_FSID_SIZE);
6587
6588         if (memcmp(fs_uuid, fs_info->fsid, BTRFS_FSID_SIZE)) {
6589                 fs_devices = open_seed_devices(fs_info, fs_uuid);
6590                 if (IS_ERR(fs_devices))
6591                         return PTR_ERR(fs_devices);
6592         }
6593
6594         device = btrfs_find_device(fs_info, devid, dev_uuid, fs_uuid);
6595         if (!device) {
6596                 if (!btrfs_test_opt(fs_info, DEGRADED)) {
6597                         btrfs_report_missing_device(fs_info, devid,
6598                                                         dev_uuid, true);
6599                         return -ENOENT;
6600                 }
6601
6602                 device = add_missing_dev(fs_devices, devid, dev_uuid);
6603                 if (IS_ERR(device)) {
6604                         btrfs_err(fs_info,
6605                                 "failed to add missing dev %llu: %ld",
6606                                 devid, PTR_ERR(device));
6607                         return PTR_ERR(device);
6608                 }
6609                 btrfs_report_missing_device(fs_info, devid, dev_uuid, false);
6610         } else {
6611                 if (!device->bdev) {
6612                         if (!btrfs_test_opt(fs_info, DEGRADED)) {
6613                                 btrfs_report_missing_device(fs_info,
6614                                                 devid, dev_uuid, true);
6615                                 return -ENOENT;
6616                         }
6617                         btrfs_report_missing_device(fs_info, devid,
6618                                                         dev_uuid, false);
6619                 }
6620
6621                 if(!device->bdev && !device->missing) {
6622                         /*
6623                          * this happens when a device that was properly setup
6624                          * in the device info lists suddenly goes bad.
6625                          * device->bdev is NULL, and so we have to set
6626                          * device->missing to one here
6627                          */
6628                         device->fs_devices->missing_devices++;
6629                         device->missing = 1;
6630                 }
6631
6632                 /* Move the device to its own fs_devices */
6633                 if (device->fs_devices != fs_devices) {
6634                         ASSERT(device->missing);
6635
6636                         list_move(&device->dev_list, &fs_devices->devices);
6637                         device->fs_devices->num_devices--;
6638                         fs_devices->num_devices++;
6639
6640                         device->fs_devices->missing_devices--;
6641                         fs_devices->missing_devices++;
6642
6643                         device->fs_devices = fs_devices;
6644                 }
6645         }
6646
6647         if (device->fs_devices != fs_info->fs_devices) {
6648                 BUG_ON(device->writeable);
6649                 if (device->generation !=
6650                     btrfs_device_generation(leaf, dev_item))
6651                         return -EINVAL;
6652         }
6653
6654         fill_device_from_item(leaf, dev_item, device);
6655         device->in_fs_metadata = 1;
6656         if (device->writeable && !device->is_tgtdev_for_dev_replace) {
6657                 device->fs_devices->total_rw_bytes += device->total_bytes;
6658                 atomic64_add(device->total_bytes - device->bytes_used,
6659                                 &fs_info->free_chunk_space);
6660         }
6661         ret = 0;
6662         return ret;
6663 }
6664
6665 int btrfs_read_sys_array(struct btrfs_fs_info *fs_info)
6666 {
6667         struct btrfs_root *root = fs_info->tree_root;
6668         struct btrfs_super_block *super_copy = fs_info->super_copy;
6669         struct extent_buffer *sb;
6670         struct btrfs_disk_key *disk_key;
6671         struct btrfs_chunk *chunk;
6672         u8 *array_ptr;
6673         unsigned long sb_array_offset;
6674         int ret = 0;
6675         u32 num_stripes;
6676         u32 array_size;
6677         u32 len = 0;
6678         u32 cur_offset;
6679         u64 type;
6680         struct btrfs_key key;
6681
6682         ASSERT(BTRFS_SUPER_INFO_SIZE <= fs_info->nodesize);
6683         /*
6684          * This will create extent buffer of nodesize, superblock size is
6685          * fixed to BTRFS_SUPER_INFO_SIZE. If nodesize > sb size, this will
6686          * overallocate but we can keep it as-is, only the first page is used.
6687          */
6688         sb = btrfs_find_create_tree_block(fs_info, BTRFS_SUPER_INFO_OFFSET);
6689         if (IS_ERR(sb))
6690                 return PTR_ERR(sb);
6691         set_extent_buffer_uptodate(sb);
6692         btrfs_set_buffer_lockdep_class(root->root_key.objectid, sb, 0);
6693         /*
6694          * The sb extent buffer is artificial and just used to read the system array.
6695          * set_extent_buffer_uptodate() call does not properly mark all it's
6696          * pages up-to-date when the page is larger: extent does not cover the
6697          * whole page and consequently check_page_uptodate does not find all
6698          * the page's extents up-to-date (the hole beyond sb),
6699          * write_extent_buffer then triggers a WARN_ON.
6700          *
6701          * Regular short extents go through mark_extent_buffer_dirty/writeback cycle,
6702          * but sb spans only this function. Add an explicit SetPageUptodate call
6703          * to silence the warning eg. on PowerPC 64.
6704          */
6705         if (PAGE_SIZE > BTRFS_SUPER_INFO_SIZE)
6706                 SetPageUptodate(sb->pages[0]);
6707
6708         write_extent_buffer(sb, super_copy, 0, BTRFS_SUPER_INFO_SIZE);
6709         array_size = btrfs_super_sys_array_size(super_copy);
6710
6711         array_ptr = super_copy->sys_chunk_array;
6712         sb_array_offset = offsetof(struct btrfs_super_block, sys_chunk_array);
6713         cur_offset = 0;
6714
6715         while (cur_offset < array_size) {
6716                 disk_key = (struct btrfs_disk_key *)array_ptr;
6717                 len = sizeof(*disk_key);
6718                 if (cur_offset + len > array_size)
6719                         goto out_short_read;
6720
6721                 btrfs_disk_key_to_cpu(&key, disk_key);
6722
6723                 array_ptr += len;
6724                 sb_array_offset += len;
6725                 cur_offset += len;
6726
6727                 if (key.type == BTRFS_CHUNK_ITEM_KEY) {
6728                         chunk = (struct btrfs_chunk *)sb_array_offset;
6729                         /*
6730                          * At least one btrfs_chunk with one stripe must be
6731                          * present, exact stripe count check comes afterwards
6732                          */
6733                         len = btrfs_chunk_item_size(1);
6734                         if (cur_offset + len > array_size)
6735                                 goto out_short_read;
6736
6737                         num_stripes = btrfs_chunk_num_stripes(sb, chunk);
6738                         if (!num_stripes) {
6739                                 btrfs_err(fs_info,
6740                                         "invalid number of stripes %u in sys_array at offset %u",
6741                                         num_stripes, cur_offset);
6742                                 ret = -EIO;
6743                                 break;
6744                         }
6745
6746                         type = btrfs_chunk_type(sb, chunk);
6747                         if ((type & BTRFS_BLOCK_GROUP_SYSTEM) == 0) {
6748                                 btrfs_err(fs_info,
6749                             "invalid chunk type %llu in sys_array at offset %u",
6750                                         type, cur_offset);
6751                                 ret = -EIO;
6752                                 break;
6753                         }
6754
6755                         len = btrfs_chunk_item_size(num_stripes);
6756                         if (cur_offset + len > array_size)
6757                                 goto out_short_read;
6758
6759                         ret = read_one_chunk(fs_info, &key, sb, chunk);
6760                         if (ret)
6761                                 break;
6762                 } else {
6763                         btrfs_err(fs_info,
6764                             "unexpected item type %u in sys_array at offset %u",
6765                                   (u32)key.type, cur_offset);
6766                         ret = -EIO;
6767                         break;
6768                 }
6769                 array_ptr += len;
6770                 sb_array_offset += len;
6771                 cur_offset += len;
6772         }
6773         clear_extent_buffer_uptodate(sb);
6774         free_extent_buffer_stale(sb);
6775         return ret;
6776
6777 out_short_read:
6778         btrfs_err(fs_info, "sys_array too short to read %u bytes at offset %u",
6779                         len, cur_offset);
6780         clear_extent_buffer_uptodate(sb);
6781         free_extent_buffer_stale(sb);
6782         return -EIO;
6783 }
6784
6785 /*
6786  * Check if all chunks in the fs are OK for read-write degraded mount
6787  *
6788  * Return true if all chunks meet the minimal RW mount requirements.
6789  * Return false if any chunk doesn't meet the minimal RW mount requirements.
6790  */
6791 bool btrfs_check_rw_degradable(struct btrfs_fs_info *fs_info)
6792 {
6793         struct btrfs_mapping_tree *map_tree = &fs_info->mapping_tree;
6794         struct extent_map *em;
6795         u64 next_start = 0;
6796         bool ret = true;
6797
6798         read_lock(&map_tree->map_tree.lock);
6799         em = lookup_extent_mapping(&map_tree->map_tree, 0, (u64)-1);
6800         read_unlock(&map_tree->map_tree.lock);
6801         /* No chunk at all? Return false anyway */
6802         if (!em) {
6803                 ret = false;
6804                 goto out;
6805         }
6806         while (em) {
6807                 struct map_lookup *map;
6808                 int missing = 0;
6809                 int max_tolerated;
6810                 int i;
6811
6812                 map = em->map_lookup;
6813                 max_tolerated =
6814                         btrfs_get_num_tolerated_disk_barrier_failures(
6815                                         map->type);
6816                 for (i = 0; i < map->num_stripes; i++) {
6817                         struct btrfs_device *dev = map->stripes[i].dev;
6818
6819                         if (!dev || !dev->bdev || dev->missing ||
6820                             dev->last_flush_error)
6821                                 missing++;
6822                 }
6823                 if (missing > max_tolerated) {
6824                         btrfs_warn(fs_info,
6825         "chunk %llu missing %d devices, max tolerance is %d for writeable mount",
6826                                    em->start, missing, max_tolerated);
6827                         free_extent_map(em);
6828                         ret = false;
6829                         goto out;
6830                 }
6831                 next_start = extent_map_end(em);
6832                 free_extent_map(em);
6833
6834                 read_lock(&map_tree->map_tree.lock);
6835                 em = lookup_extent_mapping(&map_tree->map_tree, next_start,
6836                                            (u64)(-1) - next_start);
6837                 read_unlock(&map_tree->map_tree.lock);
6838         }
6839 out:
6840         return ret;
6841 }
6842
6843 int btrfs_read_chunk_tree(struct btrfs_fs_info *fs_info)
6844 {
6845         struct btrfs_root *root = fs_info->chunk_root;
6846         struct btrfs_path *path;
6847         struct extent_buffer *leaf;
6848         struct btrfs_key key;
6849         struct btrfs_key found_key;
6850         int ret;
6851         int slot;
6852         u64 total_dev = 0;
6853
6854         path = btrfs_alloc_path();
6855         if (!path)
6856                 return -ENOMEM;
6857
6858         mutex_lock(&uuid_mutex);
6859         mutex_lock(&fs_info->chunk_mutex);
6860
6861         /*
6862          * Read all device items, and then all the chunk items. All
6863          * device items are found before any chunk item (their object id
6864          * is smaller than the lowest possible object id for a chunk
6865          * item - BTRFS_FIRST_CHUNK_TREE_OBJECTID).
6866          */
6867         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
6868         key.offset = 0;
6869         key.type = 0;
6870         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
6871         if (ret < 0)
6872                 goto error;
6873         while (1) {
6874                 leaf = path->nodes[0];
6875                 slot = path->slots[0];
6876                 if (slot >= btrfs_header_nritems(leaf)) {
6877                         ret = btrfs_next_leaf(root, path);
6878                         if (ret == 0)
6879                                 continue;
6880                         if (ret < 0)
6881                                 goto error;
6882                         break;
6883                 }
6884                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
6885                 if (found_key.type == BTRFS_DEV_ITEM_KEY) {
6886                         struct btrfs_dev_item *dev_item;
6887                         dev_item = btrfs_item_ptr(leaf, slot,
6888                                                   struct btrfs_dev_item);
6889                         ret = read_one_dev(fs_info, leaf, dev_item);
6890                         if (ret)
6891                                 goto error;
6892                         total_dev++;
6893                 } else if (found_key.type == BTRFS_CHUNK_ITEM_KEY) {
6894                         struct btrfs_chunk *chunk;
6895                         chunk = btrfs_item_ptr(leaf, slot, struct btrfs_chunk);
6896                         ret = read_one_chunk(fs_info, &found_key, leaf, chunk);
6897                         if (ret)
6898                                 goto error;
6899                 }
6900                 path->slots[0]++;
6901         }
6902
6903         /*
6904          * After loading chunk tree, we've got all device information,
6905          * do another round of validation checks.
6906          */
6907         if (total_dev != fs_info->fs_devices->total_devices) {
6908                 btrfs_err(fs_info,
6909            "super_num_devices %llu mismatch with num_devices %llu found here",
6910                           btrfs_super_num_devices(fs_info->super_copy),
6911                           total_dev);
6912                 ret = -EINVAL;
6913                 goto error;
6914         }
6915         if (btrfs_super_total_bytes(fs_info->super_copy) <
6916             fs_info->fs_devices->total_rw_bytes) {
6917                 btrfs_err(fs_info,
6918         "super_total_bytes %llu mismatch with fs_devices total_rw_bytes %llu",
6919                           btrfs_super_total_bytes(fs_info->super_copy),
6920                           fs_info->fs_devices->total_rw_bytes);
6921                 ret = -EINVAL;
6922                 goto error;
6923         }
6924         ret = 0;
6925 error:
6926         mutex_unlock(&fs_info->chunk_mutex);
6927         mutex_unlock(&uuid_mutex);
6928
6929         btrfs_free_path(path);
6930         return ret;
6931 }
6932
6933 void btrfs_init_devices_late(struct btrfs_fs_info *fs_info)
6934 {
6935         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
6936         struct btrfs_device *device;
6937
6938         while (fs_devices) {
6939                 mutex_lock(&fs_devices->device_list_mutex);
6940                 list_for_each_entry(device, &fs_devices->devices, dev_list)
6941                         device->fs_info = fs_info;
6942                 mutex_unlock(&fs_devices->device_list_mutex);
6943
6944                 fs_devices = fs_devices->seed;
6945         }
6946 }
6947
6948 static void __btrfs_reset_dev_stats(struct btrfs_device *dev)
6949 {
6950         int i;
6951
6952         for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++)
6953                 btrfs_dev_stat_reset(dev, i);
6954 }
6955
6956 int btrfs_init_dev_stats(struct btrfs_fs_info *fs_info)
6957 {
6958         struct btrfs_key key;
6959         struct btrfs_key found_key;
6960         struct btrfs_root *dev_root = fs_info->dev_root;
6961         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
6962         struct extent_buffer *eb;
6963         int slot;
6964         int ret = 0;
6965         struct btrfs_device *device;
6966         struct btrfs_path *path = NULL;
6967         int i;
6968
6969         path = btrfs_alloc_path();
6970         if (!path) {
6971                 ret = -ENOMEM;
6972                 goto out;
6973         }
6974
6975         mutex_lock(&fs_devices->device_list_mutex);
6976         list_for_each_entry(device, &fs_devices->devices, dev_list) {
6977                 int item_size;
6978                 struct btrfs_dev_stats_item *ptr;
6979
6980                 key.objectid = BTRFS_DEV_STATS_OBJECTID;
6981                 key.type = BTRFS_PERSISTENT_ITEM_KEY;
6982                 key.offset = device->devid;
6983                 ret = btrfs_search_slot(NULL, dev_root, &key, path, 0, 0);
6984                 if (ret) {
6985                         __btrfs_reset_dev_stats(device);
6986                         device->dev_stats_valid = 1;
6987                         btrfs_release_path(path);
6988                         continue;
6989                 }
6990                 slot = path->slots[0];
6991                 eb = path->nodes[0];
6992                 btrfs_item_key_to_cpu(eb, &found_key, slot);
6993                 item_size = btrfs_item_size_nr(eb, slot);
6994
6995                 ptr = btrfs_item_ptr(eb, slot,
6996                                      struct btrfs_dev_stats_item);
6997
6998                 for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++) {
6999                         if (item_size >= (1 + i) * sizeof(__le64))
7000                                 btrfs_dev_stat_set(device, i,
7001                                         btrfs_dev_stats_value(eb, ptr, i));
7002                         else
7003                                 btrfs_dev_stat_reset(device, i);
7004                 }
7005
7006                 device->dev_stats_valid = 1;
7007                 btrfs_dev_stat_print_on_load(device);
7008                 btrfs_release_path(path);
7009         }
7010         mutex_unlock(&fs_devices->device_list_mutex);
7011
7012 out:
7013         btrfs_free_path(path);
7014         return ret < 0 ? ret : 0;
7015 }
7016
7017 static int update_dev_stat_item(struct btrfs_trans_handle *trans,
7018                                 struct btrfs_fs_info *fs_info,
7019                                 struct btrfs_device *device)
7020 {
7021         struct btrfs_root *dev_root = fs_info->dev_root;
7022         struct btrfs_path *path;
7023         struct btrfs_key key;
7024         struct extent_buffer *eb;
7025         struct btrfs_dev_stats_item *ptr;
7026         int ret;
7027         int i;
7028
7029         key.objectid = BTRFS_DEV_STATS_OBJECTID;
7030         key.type = BTRFS_PERSISTENT_ITEM_KEY;
7031         key.offset = device->devid;
7032
7033         path = btrfs_alloc_path();
7034         if (!path)
7035                 return -ENOMEM;
7036         ret = btrfs_search_slot(trans, dev_root, &key, path, -1, 1);
7037         if (ret < 0) {
7038                 btrfs_warn_in_rcu(fs_info,
7039                         "error %d while searching for dev_stats item for device %s",
7040                               ret, rcu_str_deref(device->name));
7041                 goto out;
7042         }
7043
7044         if (ret == 0 &&
7045             btrfs_item_size_nr(path->nodes[0], path->slots[0]) < sizeof(*ptr)) {
7046                 /* need to delete old one and insert a new one */
7047                 ret = btrfs_del_item(trans, dev_root, path);
7048                 if (ret != 0) {
7049                         btrfs_warn_in_rcu(fs_info,
7050                                 "delete too small dev_stats item for device %s failed %d",
7051                                       rcu_str_deref(device->name), ret);
7052                         goto out;
7053                 }
7054                 ret = 1;
7055         }
7056
7057         if (ret == 1) {
7058                 /* need to insert a new item */
7059                 btrfs_release_path(path);
7060                 ret = btrfs_insert_empty_item(trans, dev_root, path,
7061                                               &key, sizeof(*ptr));
7062                 if (ret < 0) {
7063                         btrfs_warn_in_rcu(fs_info,
7064                                 "insert dev_stats item for device %s failed %d",
7065                                 rcu_str_deref(device->name), ret);
7066                         goto out;
7067                 }
7068         }
7069
7070         eb = path->nodes[0];
7071         ptr = btrfs_item_ptr(eb, path->slots[0], struct btrfs_dev_stats_item);
7072         for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++)
7073                 btrfs_set_dev_stats_value(eb, ptr, i,
7074                                           btrfs_dev_stat_read(device, i));
7075         btrfs_mark_buffer_dirty(eb);
7076
7077 out:
7078         btrfs_free_path(path);
7079         return ret;
7080 }
7081
7082 /*
7083  * called from commit_transaction. Writes all changed device stats to disk.
7084  */
7085 int btrfs_run_dev_stats(struct btrfs_trans_handle *trans,
7086                         struct btrfs_fs_info *fs_info)
7087 {
7088         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
7089         struct btrfs_device *device;
7090         int stats_cnt;
7091         int ret = 0;
7092
7093         mutex_lock(&fs_devices->device_list_mutex);
7094         list_for_each_entry(device, &fs_devices->devices, dev_list) {
7095                 if (!device->dev_stats_valid || !btrfs_dev_stats_dirty(device))
7096                         continue;
7097
7098                 stats_cnt = atomic_read(&device->dev_stats_ccnt);
7099                 ret = update_dev_stat_item(trans, fs_info, device);
7100                 if (!ret)
7101                         atomic_sub(stats_cnt, &device->dev_stats_ccnt);
7102         }
7103         mutex_unlock(&fs_devices->device_list_mutex);
7104
7105         return ret;
7106 }
7107
7108 void btrfs_dev_stat_inc_and_print(struct btrfs_device *dev, int index)
7109 {
7110         btrfs_dev_stat_inc(dev, index);
7111         btrfs_dev_stat_print_on_error(dev);
7112 }
7113
7114 static void btrfs_dev_stat_print_on_error(struct btrfs_device *dev)
7115 {
7116         if (!dev->dev_stats_valid)
7117                 return;
7118         btrfs_err_rl_in_rcu(dev->fs_info,
7119                 "bdev %s errs: wr %u, rd %u, flush %u, corrupt %u, gen %u",
7120                            rcu_str_deref(dev->name),
7121                            btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_WRITE_ERRS),
7122                            btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_READ_ERRS),
7123                            btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_FLUSH_ERRS),
7124                            btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_CORRUPTION_ERRS),
7125                            btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_GENERATION_ERRS));
7126 }
7127
7128 static void btrfs_dev_stat_print_on_load(struct btrfs_device *dev)
7129 {
7130         int i;
7131
7132         for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++)
7133                 if (btrfs_dev_stat_read(dev, i) != 0)
7134                         break;
7135         if (i == BTRFS_DEV_STAT_VALUES_MAX)
7136                 return; /* all values == 0, suppress message */
7137
7138         btrfs_info_in_rcu(dev->fs_info,
7139                 "bdev %s errs: wr %u, rd %u, flush %u, corrupt %u, gen %u",
7140                rcu_str_deref(dev->name),
7141                btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_WRITE_ERRS),
7142                btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_READ_ERRS),
7143                btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_FLUSH_ERRS),
7144                btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_CORRUPTION_ERRS),
7145                btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_GENERATION_ERRS));
7146 }
7147
7148 int btrfs_get_dev_stats(struct btrfs_fs_info *fs_info,
7149                         struct btrfs_ioctl_get_dev_stats *stats)
7150 {
7151         struct btrfs_device *dev;
7152         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
7153         int i;
7154
7155         mutex_lock(&fs_devices->device_list_mutex);
7156         dev = btrfs_find_device(fs_info, stats->devid, NULL, NULL);
7157         mutex_unlock(&fs_devices->device_list_mutex);
7158
7159         if (!dev) {
7160                 btrfs_warn(fs_info, "get dev_stats failed, device not found");
7161                 return -ENODEV;
7162         } else if (!dev->dev_stats_valid) {
7163                 btrfs_warn(fs_info, "get dev_stats failed, not yet valid");
7164                 return -ENODEV;
7165         } else if (stats->flags & BTRFS_DEV_STATS_RESET) {
7166                 for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++) {
7167                         if (stats->nr_items > i)
7168                                 stats->values[i] =
7169                                         btrfs_dev_stat_read_and_reset(dev, i);
7170                         else
7171                                 btrfs_dev_stat_reset(dev, i);
7172                 }
7173         } else {
7174                 for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++)
7175                         if (stats->nr_items > i)
7176                                 stats->values[i] = btrfs_dev_stat_read(dev, i);
7177         }
7178         if (stats->nr_items > BTRFS_DEV_STAT_VALUES_MAX)
7179                 stats->nr_items = BTRFS_DEV_STAT_VALUES_MAX;
7180         return 0;
7181 }
7182
7183 void btrfs_scratch_superblocks(struct block_device *bdev, const char *device_path)
7184 {
7185         struct buffer_head *bh;
7186         struct btrfs_super_block *disk_super;
7187         int copy_num;
7188
7189         if (!bdev)
7190                 return;
7191
7192         for (copy_num = 0; copy_num < BTRFS_SUPER_MIRROR_MAX;
7193                 copy_num++) {
7194
7195                 if (btrfs_read_dev_one_super(bdev, copy_num, &bh))
7196                         continue;
7197
7198                 disk_super = (struct btrfs_super_block *)bh->b_data;
7199
7200                 memset(&disk_super->magic, 0, sizeof(disk_super->magic));
7201                 set_buffer_dirty(bh);
7202                 sync_dirty_buffer(bh);
7203                 brelse(bh);
7204         }
7205
7206         /* Notify udev that device has changed */
7207         btrfs_kobject_uevent(bdev, KOBJ_CHANGE);
7208
7209         /* Update ctime/mtime for device path for libblkid */
7210         update_dev_time(device_path);
7211 }
7212
7213 /*
7214  * Update the size of all devices, which is used for writing out the
7215  * super blocks.
7216  */
7217 void btrfs_update_commit_device_size(struct btrfs_fs_info *fs_info)
7218 {
7219         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
7220         struct btrfs_device *curr, *next;
7221
7222         if (list_empty(&fs_devices->resized_devices))
7223                 return;
7224
7225         mutex_lock(&fs_devices->device_list_mutex);
7226         mutex_lock(&fs_info->chunk_mutex);
7227         list_for_each_entry_safe(curr, next, &fs_devices->resized_devices,
7228                                  resized_list) {
7229                 list_del_init(&curr->resized_list);
7230                 curr->commit_total_bytes = curr->disk_total_bytes;
7231         }
7232         mutex_unlock(&fs_info->chunk_mutex);
7233         mutex_unlock(&fs_devices->device_list_mutex);
7234 }
7235
7236 /* Must be invoked during the transaction commit */
7237 void btrfs_update_commit_device_bytes_used(struct btrfs_fs_info *fs_info,
7238                                         struct btrfs_transaction *transaction)
7239 {
7240         struct extent_map *em;
7241         struct map_lookup *map;
7242         struct btrfs_device *dev;
7243         int i;
7244
7245         if (list_empty(&transaction->pending_chunks))
7246                 return;
7247
7248         /* In order to kick the device replace finish process */
7249         mutex_lock(&fs_info->chunk_mutex);
7250         list_for_each_entry(em, &transaction->pending_chunks, list) {
7251                 map = em->map_lookup;
7252
7253                 for (i = 0; i < map->num_stripes; i++) {
7254                         dev = map->stripes[i].dev;
7255                         dev->commit_bytes_used = dev->bytes_used;
7256                 }
7257         }
7258         mutex_unlock(&fs_info->chunk_mutex);
7259 }
7260
7261 void btrfs_set_fs_info_ptr(struct btrfs_fs_info *fs_info)
7262 {
7263         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
7264         while (fs_devices) {
7265                 fs_devices->fs_info = fs_info;
7266                 fs_devices = fs_devices->seed;
7267         }
7268 }
7269
7270 void btrfs_reset_fs_info_ptr(struct btrfs_fs_info *fs_info)
7271 {
7272         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
7273         while (fs_devices) {
7274                 fs_devices->fs_info = NULL;
7275                 fs_devices = fs_devices->seed;
7276         }
7277 }