fs/btrfs/check-integrity.c

   1 /*
   2  * Copyright (C) STRATO AG 2011.  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
  19 /*
  20  * This module can be used to catch cases when the btrfs kernel
  21  * code executes write requests to the disk that bring the file
  22  * system in an inconsistent state. In such a state, a power-loss
  23  * or kernel panic event would cause that the data on disk is
  24  * lost or at least damaged.
  25  *
  26  * Code is added that examines all block write requests during
  27  * runtime (including writes of the super block). Three rules
  28  * are verified and an error is printed on violation of the
  29  * rules:
  30  * 1. It is not allowed to write a disk block which is
  31  *    currently referenced by the super block (either directly
  32  *    or indirectly).
  33  * 2. When a super block is written, it is verified that all
  34  *    referenced (directly or indirectly) blocks fulfill the
  35  *    following requirements:
  36  *    2a. All referenced blocks have either been present when
  37  *        the file system was mounted, (i.e., they have been
  38  *        referenced by the super block) or they have been
  39  *        written since then and the write completion callback
  40  *        was called and no write error was indicated and a
  41  *        FLUSH request to the device where these blocks are
  42  *        located was received and completed.
  43  *    2b. All referenced blocks need to have a generation
  44  *        number which is equal to the parent's number.
  45  *
  46  * One issue that was found using this module was that the log
  47  * tree on disk became temporarily corrupted because disk blocks
  48  * that had been in use for the log tree had been freed and
  49  * reused too early, while being referenced by the written super
  50  * block.
  51  *
  52  * The search term in the kernel log that can be used to filter
  53  * on the existence of detected integrity issues is
  54  * "btrfs: attempt".
  55  *
  56  * The integrity check is enabled via mount options. These
  57  * mount options are only supported if the integrity check
  58  * tool is compiled by defining BTRFS_FS_CHECK_INTEGRITY.
  59  *
  60  * Example #1, apply integrity checks to all metadata:
  61  * mount /dev/sdb1 /mnt -o check_int
  62  *
  63  * Example #2, apply integrity checks to all metadata and
  64  * to data extents:
  65  * mount /dev/sdb1 /mnt -o check_int_data
  66  *
  67  * Example #3, apply integrity checks to all metadata and dump
  68  * the tree that the super block references to kernel messages
  69  * each time after a super block was written:
  70  * mount /dev/sdb1 /mnt -o check_int,check_int_print_mask=263
  71  *
  72  * If the integrity check tool is included and activated in
  73  * the mount options, plenty of kernel memory is used, and
  74  * plenty of additional CPU cycles are spent. Enabling this
  75  * functionality is not intended for normal use. In most
  76  * cases, unless you are a btrfs developer who needs to verify
  77  * the integrity of (super)-block write requests, do not
  78  * enable the config option BTRFS_FS_CHECK_INTEGRITY to
  79  * include and compile the integrity check tool.
  80  *
  81  * Expect millions of lines of information in the kernel log with an
  82  * enabled check_int_print_mask. Therefore set LOG_BUF_SHIFT in the
  83  * kernel config to at least 26 (which is 64MB). Usually the value is
  84  * limited to 21 (which is 2MB) in init/Kconfig. The file needs to be
  85  * changed like this before LOG_BUF_SHIFT can be set to a high value:
  86  * config LOG_BUF_SHIFT
  87  *       int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
  88  *       range 12 30
  89  */
  90
  91 #include <linux/sched.h>
  92 #include <linux/slab.h>
  93 #include <linux/buffer_head.h>
  94 #include <linux/mutex.h>
  95 #include <linux/genhd.h>
  96 #include <linux/blkdev.h>
  97 #include <linux/mm.h>
  98 #include <linux/string.h>
  99 #include <linux/crc32c.h>
 100 #include "ctree.h"
 101 #include "disk-io.h"
 102 #include "transaction.h"
 103 #include "extent_io.h"
 104 #include "volumes.h"
 105 #include "print-tree.h"
 106 #include "locking.h"
 107 #include "check-integrity.h"
 108 #include "rcu-string.h"
 109 #include "compression.h"
 110
 111 #define BTRFSIC_BLOCK_HASHTABLE_SIZE 0x10000
 112 #define BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE 0x10000
 113 #define BTRFSIC_DEV2STATE_HASHTABLE_SIZE 0x100
 114 #define BTRFSIC_BLOCK_MAGIC_NUMBER 0x14491051
 115 #define BTRFSIC_BLOCK_LINK_MAGIC_NUMBER 0x11070807
 116 #define BTRFSIC_DEV2STATE_MAGIC_NUMBER 0x20111530
 117 #define BTRFSIC_BLOCK_STACK_FRAME_MAGIC_NUMBER 20111300
 118 #define BTRFSIC_TREE_DUMP_MAX_INDENT_LEVEL (200 - 6)    /* in characters,
 119                                                          * excluding " [...]" */
 120 #define BTRFSIC_GENERATION_UNKNOWN ((u64)-1)
 121
 122 /*
 123  * The definition of the bitmask fields for the print_mask.
 124  * They are specified with the mount option check_integrity_print_mask.
 125  */
 126 #define BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE                     0x00000001
 127 #define BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION         0x00000002
 128 #define BTRFSIC_PRINT_MASK_TREE_AFTER_SB_WRITE                  0x00000004
 129 #define BTRFSIC_PRINT_MASK_TREE_BEFORE_SB_WRITE                 0x00000008
 130 #define BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH                        0x00000010
 131 #define BTRFSIC_PRINT_MASK_END_IO_BIO_BH                        0x00000020
 132 #define BTRFSIC_PRINT_MASK_VERBOSE                              0x00000040
 133 #define BTRFSIC_PRINT_MASK_VERY_VERBOSE                         0x00000080
 134 #define BTRFSIC_PRINT_MASK_INITIAL_TREE                         0x00000100
 135 #define BTRFSIC_PRINT_MASK_INITIAL_ALL_TREES                    0x00000200
 136 #define BTRFSIC_PRINT_MASK_INITIAL_DATABASE                     0x00000400
 137 #define BTRFSIC_PRINT_MASK_NUM_COPIES                           0x00000800
 138 #define BTRFSIC_PRINT_MASK_TREE_WITH_ALL_MIRRORS                0x00001000
 139 #define BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH_VERBOSE                0x00002000
 140
 141 struct btrfsic_dev_state;
 142 struct btrfsic_state;
 143
 144 struct btrfsic_block {
 145         u32 magic_num;          /* only used for debug purposes */
 146         unsigned int is_metadata:1;     /* if it is meta-data, not data-data */
 147         unsigned int is_superblock:1;   /* if it is one of the superblocks */
 148         unsigned int is_iodone:1;       /* if is done by lower subsystem */
 149         unsigned int iodone_w_error:1;  /* error was indicated to endio */
 150         unsigned int never_written:1;   /* block was added because it was
 151                                          * referenced, not because it was
 152                                          * written */
 153         unsigned int mirror_num;        /* large enough to hold
 154                                          * BTRFS_SUPER_MIRROR_MAX */
 155         struct btrfsic_dev_state *dev_state;
 156         u64 dev_bytenr;         /* key, physical byte num on disk */
 157         u64 logical_bytenr;     /* logical byte num on disk */
 158         u64 generation;
 159         struct btrfs_disk_key disk_key; /* extra info to print in case of
 160                                          * issues, will not always be correct */
 161         struct list_head collision_resolving_node;      /* list node */
 162         struct list_head all_blocks_node;       /* list node */
 163
 164         /* the following two lists contain block_link items */
 165         struct list_head ref_to_list;   /* list */
 166         struct list_head ref_from_list; /* list */
 167         struct btrfsic_block *next_in_same_bio;
 168         void *orig_bio_bh_private;
 169         union {
 170                 bio_end_io_t *bio;
 171                 bh_end_io_t *bh;
 172         } orig_bio_bh_end_io;
 173         int submit_bio_bh_rw;
 174         u64 flush_gen; /* only valid if !never_written */
 175 };
 176
 177 /*
 178  * Elements of this type are allocated dynamically and required because
 179  * each block object can refer to and can be ref from multiple blocks.
 180  * The key to lookup them in the hashtable is the dev_bytenr of
 181  * the block ref to plus the one from the block referred from.
 182  * The fact that they are searchable via a hashtable and that a
 183  * ref_cnt is maintained is not required for the btrfs integrity
 184  * check algorithm itself, it is only used to make the output more
 185  * beautiful in case that an error is detected (an error is defined
 186  * as a write operation to a block while that block is still referenced).
 187  */
 188 struct btrfsic_block_link {
 189         u32 magic_num;          /* only used for debug purposes */
 190         u32 ref_cnt;
 191         struct list_head node_ref_to;   /* list node */
 192         struct list_head node_ref_from; /* list node */
 193         struct list_head collision_resolving_node;      /* list node */
 194         struct btrfsic_block *block_ref_to;
 195         struct btrfsic_block *block_ref_from;
 196         u64 parent_generation;
 197 };
 198
 199 struct btrfsic_dev_state {
 200         u32 magic_num;          /* only used for debug purposes */
 201         struct block_device *bdev;
 202         struct btrfsic_state *state;
 203         struct list_head collision_resolving_node;      /* list node */
 204         struct btrfsic_block dummy_block_for_bio_bh_flush;
 205         u64 last_flush_gen;
 206         char name[BDEVNAME_SIZE];
 207 };
 208
 209 struct btrfsic_block_hashtable {
 210         struct list_head table[BTRFSIC_BLOCK_HASHTABLE_SIZE];
 211 };
 212
 213 struct btrfsic_block_link_hashtable {
 214         struct list_head table[BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE];
 215 };
 216
 217 struct btrfsic_dev_state_hashtable {
 218         struct list_head table[BTRFSIC_DEV2STATE_HASHTABLE_SIZE];
 219 };
 220
 221 struct btrfsic_block_data_ctx {
 222         u64 start;              /* virtual bytenr */
 223         u64 dev_bytenr;         /* physical bytenr on device */
 224         u32 len;
 225         struct btrfsic_dev_state *dev;
 226         char **datav;
 227         struct page **pagev;
 228         void *mem_to_free;
 229 };
 230
 231 /* This structure is used to implement recursion without occupying
 232  * any stack space, refer to btrfsic_process_metablock() */
 233 struct btrfsic_stack_frame {
 234         u32 magic;
 235         u32 nr;
 236         int error;
 237         int i;
 238         int limit_nesting;
 239         int num_copies;
 240         int mirror_num;
 241         struct btrfsic_block *block;
 242         struct btrfsic_block_data_ctx *block_ctx;
 243         struct btrfsic_block *next_block;
 244         struct btrfsic_block_data_ctx next_block_ctx;
 245         struct btrfs_header *hdr;
 246         struct btrfsic_stack_frame *prev;
 247 };
 248
 249 /* Some state per mounted filesystem */
 250 struct btrfsic_state {
 251         u32 print_mask;
 252         int include_extent_data;
 253         int csum_size;
 254         struct list_head all_blocks_list;
 255         struct btrfsic_block_hashtable block_hashtable;
 256         struct btrfsic_block_link_hashtable block_link_hashtable;
 257         struct btrfs_fs_info *fs_info;
 258         u64 max_superblock_generation;
 259         struct btrfsic_block *latest_superblock;
 260         u32 metablock_size;
 261         u32 datablock_size;
 262 };
 263
 264 static void btrfsic_block_init(struct btrfsic_block *b);
 265 static struct btrfsic_block *btrfsic_block_alloc(void);
 266 static void btrfsic_block_free(struct btrfsic_block *b);
 267 static void btrfsic_block_link_init(struct btrfsic_block_link *n);
 268 static struct btrfsic_block_link *btrfsic_block_link_alloc(void);
 269 static void btrfsic_block_link_free(struct btrfsic_block_link *n);
 270 static void btrfsic_dev_state_init(struct btrfsic_dev_state *ds);
 271 static struct btrfsic_dev_state *btrfsic_dev_state_alloc(void);
 272 static void btrfsic_dev_state_free(struct btrfsic_dev_state *ds);
 273 static void btrfsic_block_hashtable_init(struct btrfsic_block_hashtable *h);
 274 static void btrfsic_block_hashtable_add(struct btrfsic_block *b,
 275                                         struct btrfsic_block_hashtable *h);
 276 static void btrfsic_block_hashtable_remove(struct btrfsic_block *b);
 277 static struct btrfsic_block *btrfsic_block_hashtable_lookup(
 278                 struct block_device *bdev,
 279                 u64 dev_bytenr,
 280                 struct btrfsic_block_hashtable *h);
 281 static void btrfsic_block_link_hashtable_init(
 282                 struct btrfsic_block_link_hashtable *h);
 283 static void btrfsic_block_link_hashtable_add(
 284                 struct btrfsic_block_link *l,
 285                 struct btrfsic_block_link_hashtable *h);
 286 static void btrfsic_block_link_hashtable_remove(struct btrfsic_block_link *l);
 287 static struct btrfsic_block_link *btrfsic_block_link_hashtable_lookup(
 288                 struct block_device *bdev_ref_to,
 289                 u64 dev_bytenr_ref_to,
 290                 struct block_device *bdev_ref_from,
 291                 u64 dev_bytenr_ref_from,
 292                 struct btrfsic_block_link_hashtable *h);
 293 static void btrfsic_dev_state_hashtable_init(
 294                 struct btrfsic_dev_state_hashtable *h);
 295 static void btrfsic_dev_state_hashtable_add(
 296                 struct btrfsic_dev_state *ds,
 297                 struct btrfsic_dev_state_hashtable *h);
 298 static void btrfsic_dev_state_hashtable_remove(struct btrfsic_dev_state *ds);
 299 static struct btrfsic_dev_state *btrfsic_dev_state_hashtable_lookup(dev_t dev,
 300                 struct btrfsic_dev_state_hashtable *h);
 301 static struct btrfsic_stack_frame *btrfsic_stack_frame_alloc(void);
 302 static void btrfsic_stack_frame_free(struct btrfsic_stack_frame *sf);
 303 static int btrfsic_process_superblock(struct btrfsic_state *state,
 304                                       struct btrfs_fs_devices *fs_devices);
 305 static int btrfsic_process_metablock(struct btrfsic_state *state,
 306                                      struct btrfsic_block *block,
 307                                      struct btrfsic_block_data_ctx *block_ctx,
 308                                      int limit_nesting, int force_iodone_flag);
 309 static void btrfsic_read_from_block_data(
 310         struct btrfsic_block_data_ctx *block_ctx,
 311         void *dst, u32 offset, size_t len);
 312 static int btrfsic_create_link_to_next_block(
 313                 struct btrfsic_state *state,
 314                 struct btrfsic_block *block,
 315                 struct btrfsic_block_data_ctx
 316                 *block_ctx, u64 next_bytenr,
 317                 int limit_nesting,
 318                 struct btrfsic_block_data_ctx *next_block_ctx,
 319                 struct btrfsic_block **next_blockp,
 320                 int force_iodone_flag,
 321                 int *num_copiesp, int *mirror_nump,
 322                 struct btrfs_disk_key *disk_key,
 323                 u64 parent_generation);
 324 static int btrfsic_handle_extent_data(struct btrfsic_state *state,
 325                                       struct btrfsic_block *block,
 326                                       struct btrfsic_block_data_ctx *block_ctx,
 327                                       u32 item_offset, int force_iodone_flag);
 328 static int btrfsic_map_block(struct btrfsic_state *state, u64 bytenr, u32 len,
 329                              struct btrfsic_block_data_ctx *block_ctx_out,
 330                              int mirror_num);
 331 static void btrfsic_release_block_ctx(struct btrfsic_block_data_ctx *block_ctx);
 332 static int btrfsic_read_block(struct btrfsic_state *state,
 333                               struct btrfsic_block_data_ctx *block_ctx);
 334 static void btrfsic_dump_database(struct btrfsic_state *state);
 335 static int btrfsic_test_for_metadata(struct btrfsic_state *state,
 336                                      char **datav, unsigned int num_pages);
 337 static void btrfsic_process_written_block(struct btrfsic_dev_state *dev_state,
 338                                           u64 dev_bytenr, char **mapped_datav,
 339                                           unsigned int num_pages,
 340                                           struct bio *bio, int *bio_is_patched,
 341                                           struct buffer_head *bh,
 342                                           int submit_bio_bh_rw);
 343 static int btrfsic_process_written_superblock(
 344                 struct btrfsic_state *state,
 345                 struct btrfsic_block *const block,
 346                 struct btrfs_super_block *const super_hdr);
 347 static void btrfsic_bio_end_io(struct bio *bp);
 348 static void btrfsic_bh_end_io(struct buffer_head *bh, int uptodate);
 349 static int btrfsic_is_block_ref_by_superblock(const struct btrfsic_state *state,
 350                                               const struct btrfsic_block *block,
 351                                               int recursion_level);
 352 static int btrfsic_check_all_ref_blocks(struct btrfsic_state *state,
 353                                         struct btrfsic_block *const block,
 354                                         int recursion_level);
 355 static void btrfsic_print_add_link(const struct btrfsic_state *state,
 356                                    const struct btrfsic_block_link *l);
 357 static void btrfsic_print_rem_link(const struct btrfsic_state *state,
 358                                    const struct btrfsic_block_link *l);
 359 static char btrfsic_get_block_type(const struct btrfsic_state *state,
 360                                    const struct btrfsic_block *block);
 361 static void btrfsic_dump_tree(const struct btrfsic_state *state);
 362 static void btrfsic_dump_tree_sub(const struct btrfsic_state *state,
 363                                   const struct btrfsic_block *block,
 364                                   int indent_level);
 365 static struct btrfsic_block_link *btrfsic_block_link_lookup_or_add(
 366                 struct btrfsic_state *state,
 367                 struct btrfsic_block_data_ctx *next_block_ctx,
 368                 struct btrfsic_block *next_block,
 369                 struct btrfsic_block *from_block,
 370                 u64 parent_generation);
 371 static struct btrfsic_block *btrfsic_block_lookup_or_add(
 372                 struct btrfsic_state *state,
 373                 struct btrfsic_block_data_ctx *block_ctx,
 374                 const char *additional_string,
 375                 int is_metadata,
 376                 int is_iodone,
 377                 int never_written,
 378                 int mirror_num,
 379                 int *was_created);
 380 static int btrfsic_process_superblock_dev_mirror(
 381                 struct btrfsic_state *state,
 382                 struct btrfsic_dev_state *dev_state,
 383                 struct btrfs_device *device,
 384                 int superblock_mirror_num,
 385                 struct btrfsic_dev_state **selected_dev_state,
 386                 struct btrfs_super_block *selected_super);
 387 static struct btrfsic_dev_state *btrfsic_dev_state_lookup(dev_t dev);
 388 static void btrfsic_cmp_log_and_dev_bytenr(struct btrfsic_state *state,
 389                                            u64 bytenr,
 390                                            struct btrfsic_dev_state *dev_state,
 391                                            u64 dev_bytenr);
 392
 393 static struct mutex btrfsic_mutex;
 394 static int btrfsic_is_initialized;
 395 static struct btrfsic_dev_state_hashtable btrfsic_dev_state_hashtable;
 396
 397
 398 static void btrfsic_block_init(struct btrfsic_block *b)
 399 {
 400         b->magic_num = BTRFSIC_BLOCK_MAGIC_NUMBER;
 401         b->dev_state = NULL;
 402         b->dev_bytenr = 0;
 403         b->logical_bytenr = 0;
 404         b->generation = BTRFSIC_GENERATION_UNKNOWN;
 405         b->disk_key.objectid = 0;
 406         b->disk_key.type = 0;
 407         b->disk_key.offset = 0;
 408         b->is_metadata = 0;
 409         b->is_superblock = 0;
 410         b->is_iodone = 0;
 411         b->iodone_w_error = 0;
 412         b->never_written = 0;
 413         b->mirror_num = 0;
 414         b->next_in_same_bio = NULL;
 415         b->orig_bio_bh_private = NULL;
 416         b->orig_bio_bh_end_io.bio = NULL;
 417         INIT_LIST_HEAD(&b->collision_resolving_node);
 418         INIT_LIST_HEAD(&b->all_blocks_node);
 419         INIT_LIST_HEAD(&b->ref_to_list);
 420         INIT_LIST_HEAD(&b->ref_from_list);
 421         b->submit_bio_bh_rw = 0;
 422         b->flush_gen = 0;
 423 }
 424
 425 static struct btrfsic_block *btrfsic_block_alloc(void)
 426 {
 427         struct btrfsic_block *b;
 428
 429         b = kzalloc(sizeof(*b), GFP_NOFS);
 430         if (NULL != b)
 431                 btrfsic_block_init(b);
 432
 433         return b;
 434 }
 435
 436 static void btrfsic_block_free(struct btrfsic_block *b)
 437 {
 438         BUG_ON(!(NULL == b || BTRFSIC_BLOCK_MAGIC_NUMBER == b->magic_num));
 439         kfree(b);
 440 }
 441
 442 static void btrfsic_block_link_init(struct btrfsic_block_link *l)
 443 {
 444         l->magic_num = BTRFSIC_BLOCK_LINK_MAGIC_NUMBER;
 445         l->ref_cnt = 1;
 446         INIT_LIST_HEAD(&l->node_ref_to);
 447         INIT_LIST_HEAD(&l->node_ref_from);
 448         INIT_LIST_HEAD(&l->collision_resolving_node);
 449         l->block_ref_to = NULL;
 450         l->block_ref_from = NULL;
 451 }
 452
 453 static struct btrfsic_block_link *btrfsic_block_link_alloc(void)
 454 {
 455         struct btrfsic_block_link *l;
 456
 457         l = kzalloc(sizeof(*l), GFP_NOFS);
 458         if (NULL != l)
 459                 btrfsic_block_link_init(l);
 460
 461         return l;
 462 }
 463
 464 static void btrfsic_block_link_free(struct btrfsic_block_link *l)
 465 {
 466         BUG_ON(!(NULL == l || BTRFSIC_BLOCK_LINK_MAGIC_NUMBER == l->magic_num));
 467         kfree(l);
 468 }
 469
 470 static void btrfsic_dev_state_init(struct btrfsic_dev_state *ds)
 471 {
 472         ds->magic_num = BTRFSIC_DEV2STATE_MAGIC_NUMBER;
 473         ds->bdev = NULL;
 474         ds->state = NULL;
 475         ds->name[0] = '\0';
 476         INIT_LIST_HEAD(&ds->collision_resolving_node);
 477         ds->last_flush_gen = 0;
 478         btrfsic_block_init(&ds->dummy_block_for_bio_bh_flush);
 479         ds->dummy_block_for_bio_bh_flush.is_iodone = 1;
 480         ds->dummy_block_for_bio_bh_flush.dev_state = ds;
 481 }
 482
 483 static struct btrfsic_dev_state *btrfsic_dev_state_alloc(void)
 484 {
 485         struct btrfsic_dev_state *ds;
 486
 487         ds = kzalloc(sizeof(*ds), GFP_NOFS);
 488         if (NULL != ds)
 489                 btrfsic_dev_state_init(ds);
 490
 491         return ds;
 492 }
 493
 494 static void btrfsic_dev_state_free(struct btrfsic_dev_state *ds)
 495 {
 496         BUG_ON(!(NULL == ds ||
 497                  BTRFSIC_DEV2STATE_MAGIC_NUMBER == ds->magic_num));
 498         kfree(ds);
 499 }
 500
 501 static void btrfsic_block_hashtable_init(struct btrfsic_block_hashtable *h)
 502 {
 503         int i;
 504
 505         for (i = 0; i < BTRFSIC_BLOCK_HASHTABLE_SIZE; i++)
 506                 INIT_LIST_HEAD(h->table + i);
 507 }
 508
 509 static void btrfsic_block_hashtable_add(struct btrfsic_block *b,
 510                                         struct btrfsic_block_hashtable *h)
 511 {
 512         const unsigned int hashval =
 513             (((unsigned int)(b->dev_bytenr >> 16)) ^
 514              ((unsigned int)((uintptr_t)b->dev_state->bdev))) &
 515              (BTRFSIC_BLOCK_HASHTABLE_SIZE - 1);
 516
 517         list_add(&b->collision_resolving_node, h->table + hashval);
 518 }
 519
 520 static void btrfsic_block_hashtable_remove(struct btrfsic_block *b)
 521 {
 522         list_del(&b->collision_resolving_node);
 523 }
 524
 525 static struct btrfsic_block *btrfsic_block_hashtable_lookup(
 526                 struct block_device *bdev,
 527                 u64 dev_bytenr,
 528                 struct btrfsic_block_hashtable *h)
 529 {
 530         const unsigned int hashval =
 531             (((unsigned int)(dev_bytenr >> 16)) ^
 532              ((unsigned int)((uintptr_t)bdev))) &
 533              (BTRFSIC_BLOCK_HASHTABLE_SIZE - 1);
 534         struct btrfsic_block *b;
 535
 536         list_for_each_entry(b, h->table + hashval, collision_resolving_node) {
 537                 if (b->dev_state->bdev == bdev && b->dev_bytenr == dev_bytenr)
 538                         return b;
 539         }
 540
 541         return NULL;
 542 }
 543
 544 static void btrfsic_block_link_hashtable_init(
 545                 struct btrfsic_block_link_hashtable *h)
 546 {
 547         int i;
 548
 549         for (i = 0; i < BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE; i++)
 550                 INIT_LIST_HEAD(h->table + i);
 551 }
 552
 553 static void btrfsic_block_link_hashtable_add(
 554                 struct btrfsic_block_link *l,
 555                 struct btrfsic_block_link_hashtable *h)
 556 {
 557         const unsigned int hashval =
 558             (((unsigned int)(l->block_ref_to->dev_bytenr >> 16)) ^
 559              ((unsigned int)(l->block_ref_from->dev_bytenr >> 16)) ^
 560              ((unsigned int)((uintptr_t)l->block_ref_to->dev_state->bdev)) ^
 561              ((unsigned int)((uintptr_t)l->block_ref_from->dev_state->bdev)))
 562              & (BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE - 1);
 563
 564         BUG_ON(NULL == l->block_ref_to);
 565         BUG_ON(NULL == l->block_ref_from);
 566         list_add(&l->collision_resolving_node, h->table + hashval);
 567 }
 568
 569 static void btrfsic_block_link_hashtable_remove(struct btrfsic_block_link *l)
 570 {
 571         list_del(&l->collision_resolving_node);
 572 }
 573
 574 static struct btrfsic_block_link *btrfsic_block_link_hashtable_lookup(
 575                 struct block_device *bdev_ref_to,
 576                 u64 dev_bytenr_ref_to,
 577                 struct block_device *bdev_ref_from,
 578                 u64 dev_bytenr_ref_from,
 579                 struct btrfsic_block_link_hashtable *h)
 580 {
 581         const unsigned int hashval =
 582             (((unsigned int)(dev_bytenr_ref_to >> 16)) ^
 583              ((unsigned int)(dev_bytenr_ref_from >> 16)) ^
 584              ((unsigned int)((uintptr_t)bdev_ref_to)) ^
 585              ((unsigned int)((uintptr_t)bdev_ref_from))) &
 586              (BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE - 1);
 587         struct btrfsic_block_link *l;
 588
 589         list_for_each_entry(l, h->table + hashval, collision_resolving_node) {
 590                 BUG_ON(NULL == l->block_ref_to);
 591                 BUG_ON(NULL == l->block_ref_from);
 592                 if (l->block_ref_to->dev_state->bdev == bdev_ref_to &&
 593                     l->block_ref_to->dev_bytenr == dev_bytenr_ref_to &&
 594                     l->block_ref_from->dev_state->bdev == bdev_ref_from &&
 595                     l->block_ref_from->dev_bytenr == dev_bytenr_ref_from)
 596                         return l;
 597         }
 598
 599         return NULL;
 600 }
 601
 602 static void btrfsic_dev_state_hashtable_init(
 603                 struct btrfsic_dev_state_hashtable *h)
 604 {
 605         int i;
 606
 607         for (i = 0; i < BTRFSIC_DEV2STATE_HASHTABLE_SIZE; i++)
 608                 INIT_LIST_HEAD(h->table + i);
 609 }
 610
 611 static void btrfsic_dev_state_hashtable_add(
 612                 struct btrfsic_dev_state *ds,
 613                 struct btrfsic_dev_state_hashtable *h)
 614 {
 615         const unsigned int hashval =
 616             (((unsigned int)((uintptr_t)ds->bdev->bd_dev)) &
 617              (BTRFSIC_DEV2STATE_HASHTABLE_SIZE - 1));
 618
 619         list_add(&ds->collision_resolving_node, h->table + hashval);
 620 }
 621
 622 static void btrfsic_dev_state_hashtable_remove(struct btrfsic_dev_state *ds)
 623 {
 624         list_del(&ds->collision_resolving_node);
 625 }
 626
 627 static struct btrfsic_dev_state *btrfsic_dev_state_hashtable_lookup(dev_t dev,
 628                 struct btrfsic_dev_state_hashtable *h)
 629 {
 630         const unsigned int hashval =
 631                 dev & (BTRFSIC_DEV2STATE_HASHTABLE_SIZE - 1);
 632         struct btrfsic_dev_state *ds;
 633
 634         list_for_each_entry(ds, h->table + hashval, collision_resolving_node) {
 635                 if (ds->bdev->bd_dev == dev)
 636                         return ds;
 637         }
 638
 639         return NULL;
 640 }
 641
 642 static int btrfsic_process_superblock(struct btrfsic_state *state,
 643                                       struct btrfs_fs_devices *fs_devices)
 644 {
 645         struct btrfs_fs_info *fs_info = state->fs_info;
 646         struct btrfs_super_block *selected_super;
 647         struct list_head *dev_head = &fs_devices->devices;
 648         struct btrfs_device *device;
 649         struct btrfsic_dev_state *selected_dev_state = NULL;
 650         int ret = 0;
 651         int pass;
 652
 653         BUG_ON(NULL == state);
 654         selected_super = kzalloc(sizeof(*selected_super), GFP_NOFS);
 655         if (NULL == selected_super) {
 656                 pr_info("btrfsic: error, kmalloc failed!\n");
 657                 return -ENOMEM;
 658         }
 659
 660         list_for_each_entry(device, dev_head, dev_list) {
 661                 int i;
 662                 struct btrfsic_dev_state *dev_state;
 663
 664                 if (!device->bdev || !device->name)
 665                         continue;
 666
 667                 dev_state = btrfsic_dev_state_lookup(device->bdev->bd_dev);
 668                 BUG_ON(NULL == dev_state);
 669                 for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
 670                         ret = btrfsic_process_superblock_dev_mirror(
 671                                         state, dev_state, device, i,
 672                                         &selected_dev_state, selected_super);
 673                         if (0 != ret && 0 == i) {
 674                                 kfree(selected_super);
 675                                 return ret;
 676                         }
 677                 }
 678         }
 679
 680         if (NULL == state->latest_superblock) {
 681                 pr_info("btrfsic: no superblock found!\n");
 682                 kfree(selected_super);
 683                 return -1;
 684         }
 685
 686         state->csum_size = btrfs_super_csum_size(selected_super);
 687
 688         for (pass = 0; pass < 3; pass++) {
 689                 int num_copies;
 690                 int mirror_num;
 691                 u64 next_bytenr;
 692
 693                 switch (pass) {
 694                 case 0:
 695                         next_bytenr = btrfs_super_root(selected_super);
 696                         if (state->print_mask &
 697                             BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
 698                                 pr_info("root@%llu\n", next_bytenr);
 699                         break;
 700                 case 1:
 701                         next_bytenr = btrfs_super_chunk_root(selected_super);
 702                         if (state->print_mask &
 703                             BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
 704                                 pr_info("chunk@%llu\n", next_bytenr);
 705                         break;
 706                 case 2:
 707                         next_bytenr = btrfs_super_log_root(selected_super);
 708                         if (0 == next_bytenr)
 709                                 continue;
 710                         if (state->print_mask &
 711                             BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
 712                                 pr_info("log@%llu\n", next_bytenr);
 713                         break;
 714                 }
 715
 716                 num_copies = btrfs_num_copies(fs_info, next_bytenr,
 717                                               state->metablock_size);
 718                 if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
 719                         pr_info("num_copies(log_bytenr=%llu) = %d\n",
 720                                next_bytenr, num_copies);
 721
 722                 for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
 723                         struct btrfsic_block *next_block;
 724                         struct btrfsic_block_data_ctx tmp_next_block_ctx;
 725                         struct btrfsic_block_link *l;
 726
 727                         ret = btrfsic_map_block(state, next_bytenr,
 728                                                 state->metablock_size,
 729                                                 &tmp_next_block_ctx,
 730                                                 mirror_num);
 731                         if (ret) {
 732                                 pr_info("btrfsic: btrfsic_map_block(root @%llu, mirror %d) failed!\n",
 733                                        next_bytenr, mirror_num);
 734                                 kfree(selected_super);
 735                                 return -1;
 736                         }
 737
 738                         next_block = btrfsic_block_hashtable_lookup(
 739                                         tmp_next_block_ctx.dev->bdev,
 740                                         tmp_next_block_ctx.dev_bytenr,
 741                                         &state->block_hashtable);
 742                         BUG_ON(NULL == next_block);
 743
 744                         l = btrfsic_block_link_hashtable_lookup(
 745                                         tmp_next_block_ctx.dev->bdev,
 746                                         tmp_next_block_ctx.dev_bytenr,
 747                                         state->latest_superblock->dev_state->
 748                                         bdev,
 749                                         state->latest_superblock->dev_bytenr,
 750                                         &state->block_link_hashtable);
 751                         BUG_ON(NULL == l);
 752
 753                         ret = btrfsic_read_block(state, &tmp_next_block_ctx);
 754                         if (ret < (int)PAGE_SIZE) {
 755                                 pr_info("btrfsic: read @logical %llu failed!\n",
 756                                        tmp_next_block_ctx.start);
 757                                 btrfsic_release_block_ctx(&tmp_next_block_ctx);
 758                                 kfree(selected_super);
 759                                 return -1;
 760                         }
 761
 762                         ret = btrfsic_process_metablock(state,
 763                                                         next_block,
 764                                                         &tmp_next_block_ctx,
 765                                                         BTRFS_MAX_LEVEL + 3, 1);
 766                         btrfsic_release_block_ctx(&tmp_next_block_ctx);
 767                 }
 768         }
 769
 770         kfree(selected_super);
 771         return ret;
 772 }
 773
 774 static int btrfsic_process_superblock_dev_mirror(
 775                 struct btrfsic_state *state,
 776                 struct btrfsic_dev_state *dev_state,
 777                 struct btrfs_device *device,
 778                 int superblock_mirror_num,
 779                 struct btrfsic_dev_state **selected_dev_state,
 780                 struct btrfs_super_block *selected_super)
 781 {
 782         struct btrfs_fs_info *fs_info = state->fs_info;
 783         struct btrfs_super_block *super_tmp;
 784         u64 dev_bytenr;
 785         struct buffer_head *bh;
 786         struct btrfsic_block *superblock_tmp;
 787         int pass;
 788         struct block_device *const superblock_bdev = device->bdev;
 789
 790         /* super block bytenr is always the unmapped device bytenr */
 791         dev_bytenr = btrfs_sb_offset(superblock_mirror_num);
 792         if (dev_bytenr + BTRFS_SUPER_INFO_SIZE > device->commit_total_bytes)
 793                 return -1;
 794         bh = __bread(superblock_bdev, dev_bytenr / BTRFS_BDEV_BLOCKSIZE,
 795                      BTRFS_SUPER_INFO_SIZE);
 796         if (NULL == bh)
 797                 return -1;
 798         super_tmp = (struct btrfs_super_block *)
 799             (bh->b_data + (dev_bytenr & (BTRFS_BDEV_BLOCKSIZE - 1)));
 800
 801         if (btrfs_super_bytenr(super_tmp) != dev_bytenr ||
 802             btrfs_super_magic(super_tmp) != BTRFS_MAGIC ||
 803             memcmp(device->uuid, super_tmp->dev_item.uuid, BTRFS_UUID_SIZE) ||
 804             btrfs_super_nodesize(super_tmp) != state->metablock_size ||
 805             btrfs_super_sectorsize(super_tmp) != state->datablock_size) {
 806                 brelse(bh);
 807                 return 0;
 808         }
 809
 810         superblock_tmp =
 811             btrfsic_block_hashtable_lookup(superblock_bdev,
 812                                            dev_bytenr,
 813                                            &state->block_hashtable);
 814         if (NULL == superblock_tmp) {
 815                 superblock_tmp = btrfsic_block_alloc();
 816                 if (NULL == superblock_tmp) {
 817                         pr_info("btrfsic: error, kmalloc failed!\n");
 818                         brelse(bh);
 819                         return -1;
 820                 }
 821                 /* for superblock, only the dev_bytenr makes sense */
 822                 superblock_tmp->dev_bytenr = dev_bytenr;
 823                 superblock_tmp->dev_state = dev_state;
 824                 superblock_tmp->logical_bytenr = dev_bytenr;
 825                 superblock_tmp->generation = btrfs_super_generation(super_tmp);
 826                 superblock_tmp->is_metadata = 1;
 827                 superblock_tmp->is_superblock = 1;
 828                 superblock_tmp->is_iodone = 1;
 829                 superblock_tmp->never_written = 0;
 830                 superblock_tmp->mirror_num = 1 + superblock_mirror_num;
 831                 if (state->print_mask & BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE)
 832                         btrfs_info_in_rcu(fs_info,
 833                                 "new initial S-block (bdev %p, %s) @%llu (%s/%llu/%d)",
 834                                      superblock_bdev,
 835                                      rcu_str_deref(device->name), dev_bytenr,
 836                                      dev_state->name, dev_bytenr,
 837                                      superblock_mirror_num);
 838                 list_add(&superblock_tmp->all_blocks_node,
 839                          &state->all_blocks_list);
 840                 btrfsic_block_hashtable_add(superblock_tmp,
 841                                             &state->block_hashtable);
 842         }
 843
 844         /* select the one with the highest generation field */
 845         if (btrfs_super_generation(super_tmp) >
 846             state->max_superblock_generation ||
 847             0 == state->max_superblock_generation) {
 848                 memcpy(selected_super, super_tmp, sizeof(*selected_super));
 849                 *selected_dev_state = dev_state;
 850                 state->max_superblock_generation =
 851                     btrfs_super_generation(super_tmp);
 852                 state->latest_superblock = superblock_tmp;
 853         }
 854
 855         for (pass = 0; pass < 3; pass++) {
 856                 u64 next_bytenr;
 857                 int num_copies;
 858                 int mirror_num;
 859                 const char *additional_string = NULL;
 860                 struct btrfs_disk_key tmp_disk_key;
 861
 862                 tmp_disk_key.type = BTRFS_ROOT_ITEM_KEY;
 863                 tmp_disk_key.offset = 0;
 864                 switch (pass) {
 865                 case 0:
 866                         btrfs_set_disk_key_objectid(&tmp_disk_key,
 867                                                     BTRFS_ROOT_TREE_OBJECTID);
 868                         additional_string = "initial root ";
 869                         next_bytenr = btrfs_super_root(super_tmp);
 870                         break;
 871                 case 1:
 872                         btrfs_set_disk_key_objectid(&tmp_disk_key,
 873                                                     BTRFS_CHUNK_TREE_OBJECTID);
 874                         additional_string = "initial chunk ";
 875                         next_bytenr = btrfs_super_chunk_root(super_tmp);
 876                         break;
 877                 case 2:
 878                         btrfs_set_disk_key_objectid(&tmp_disk_key,
 879                                                     BTRFS_TREE_LOG_OBJECTID);
 880                         additional_string = "initial log ";
 881                         next_bytenr = btrfs_super_log_root(super_tmp);
 882                         if (0 == next_bytenr)
 883                                 continue;
 884                         break;
 885                 }
 886
 887                 num_copies = btrfs_num_copies(fs_info, next_bytenr,
 888                                               state->metablock_size);
 889                 if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
 890                         pr_info("num_copies(log_bytenr=%llu) = %d\n",
 891                                next_bytenr, num_copies);
 892                 for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
 893                         struct btrfsic_block *next_block;
 894                         struct btrfsic_block_data_ctx tmp_next_block_ctx;
 895                         struct btrfsic_block_link *l;
 896
 897                         if (btrfsic_map_block(state, next_bytenr,
 898                                               state->metablock_size,
 899                                               &tmp_next_block_ctx,
 900                                               mirror_num)) {
 901                                 pr_info("btrfsic: btrfsic_map_block(bytenr @%llu, mirror %d) failed!\n",
 902                                        next_bytenr, mirror_num);
 903                                 brelse(bh);
 904                                 return -1;
 905                         }
 906
 907                         next_block = btrfsic_block_lookup_or_add(
 908                                         state, &tmp_next_block_ctx,
 909                                         additional_string, 1, 1, 0,
 910                                         mirror_num, NULL);
 911                         if (NULL == next_block) {
 912                                 btrfsic_release_block_ctx(&tmp_next_block_ctx);
 913                                 brelse(bh);
 914                                 return -1;
 915                         }
 916
 917                         next_block->disk_key = tmp_disk_key;
 918                         next_block->generation = BTRFSIC_GENERATION_UNKNOWN;
 919                         l = btrfsic_block_link_lookup_or_add(
 920                                         state, &tmp_next_block_ctx,
 921                                         next_block, superblock_tmp,
 922                                         BTRFSIC_GENERATION_UNKNOWN);
 923                         btrfsic_release_block_ctx(&tmp_next_block_ctx);
 924                         if (NULL == l) {
 925                                 brelse(bh);
 926                                 return -1;
 927                         }
 928                 }
 929         }
 930         if (state->print_mask & BTRFSIC_PRINT_MASK_INITIAL_ALL_TREES)
 931                 btrfsic_dump_tree_sub(state, superblock_tmp, 0);
 932
 933         brelse(bh);
 934         return 0;
 935 }
 936
 937 static struct btrfsic_stack_frame *btrfsic_stack_frame_alloc(void)
 938 {
 939         struct btrfsic_stack_frame *sf;
 940
 941         sf = kzalloc(sizeof(*sf), GFP_NOFS);
 942         if (NULL == sf)
 943                 pr_info("btrfsic: alloc memory failed!\n");
 944         else
 945                 sf->magic = BTRFSIC_BLOCK_STACK_FRAME_MAGIC_NUMBER;
 946         return sf;
 947 }
 948
 949 static void btrfsic_stack_frame_free(struct btrfsic_stack_frame *sf)
 950 {
 951         BUG_ON(!(NULL == sf ||
 952                  BTRFSIC_BLOCK_STACK_FRAME_MAGIC_NUMBER == sf->magic));
 953         kfree(sf);
 954 }
 955
 956 static int btrfsic_process_metablock(
 957                 struct btrfsic_state *state,
 958                 struct btrfsic_block *const first_block,
 959                 struct btrfsic_block_data_ctx *const first_block_ctx,
 960                 int first_limit_nesting, int force_iodone_flag)
 961 {
 962         struct btrfsic_stack_frame initial_stack_frame = { 0 };
 963         struct btrfsic_stack_frame *sf;
 964         struct btrfsic_stack_frame *next_stack;
 965         struct btrfs_header *const first_hdr =
 966                 (struct btrfs_header *)first_block_ctx->datav[0];
 967
 968         BUG_ON(!first_hdr);
 969         sf = &initial_stack_frame;
 970         sf->error = 0;
 971         sf->i = -1;
 972         sf->limit_nesting = first_limit_nesting;
 973         sf->block = first_block;
 974         sf->block_ctx = first_block_ctx;
 975         sf->next_block = NULL;
 976         sf->hdr = first_hdr;
 977         sf->prev = NULL;
 978
 979 continue_with_new_stack_frame:
 980         sf->block->generation = le64_to_cpu(sf->hdr->generation);
 981         if (0 == sf->hdr->level) {
 982                 struct btrfs_leaf *const leafhdr =
 983                     (struct btrfs_leaf *)sf->hdr;
 984
 985                 if (-1 == sf->i) {
 986                         sf->nr = btrfs_stack_header_nritems(&leafhdr->header);
 987
 988                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
 989                                 pr_info("leaf %llu items %d generation %llu owner %llu\n",
 990                                        sf->block_ctx->start, sf->nr,
 991                                        btrfs_stack_header_generation(
 992                                                &leafhdr->header),
 993                                        btrfs_stack_header_owner(
 994                                                &leafhdr->header));
 995                 }
 996
 997 continue_with_current_leaf_stack_frame:
 998                 if (0 == sf->num_copies || sf->mirror_num > sf->num_copies) {
 999                         sf->i++;
1000                         sf->num_copies = 0;
1001                 }
1002
1003                 if (sf->i < sf->nr) {
1004                         struct btrfs_item disk_item;
1005                         u32 disk_item_offset =
1006                                 (uintptr_t)(leafhdr->items + sf->i) -
1007                                 (uintptr_t)leafhdr;
1008                         struct btrfs_disk_key *disk_key;
1009                         u8 type;
1010                         u32 item_offset;
1011                         u32 item_size;
1012
1013                         if (disk_item_offset + sizeof(struct btrfs_item) >
1014                             sf->block_ctx->len) {
1015 leaf_item_out_of_bounce_error:
1016                                 pr_info("btrfsic: leaf item out of bounce at logical %llu, dev %s\n",
1017                                        sf->block_ctx->start,
1018                                        sf->block_ctx->dev->name);
1019                                 goto one_stack_frame_backwards;
1020                         }
1021                         btrfsic_read_from_block_data(sf->block_ctx,
1022                                                      &disk_item,
1023                                                      disk_item_offset,
1024                                                      sizeof(struct btrfs_item));
1025                         item_offset = btrfs_stack_item_offset(&disk_item);
1026                         item_size = btrfs_stack_item_size(&disk_item);
1027                         disk_key = &disk_item.key;
1028                         type = btrfs_disk_key_type(disk_key);
1029
1030                         if (BTRFS_ROOT_ITEM_KEY == type) {
1031                                 struct btrfs_root_item root_item;
1032                                 u32 root_item_offset;
1033                                 u64 next_bytenr;
1034
1035                                 root_item_offset = item_offset +
1036                                         offsetof(struct btrfs_leaf, items);
1037                                 if (root_item_offset + item_size >
1038                                     sf->block_ctx->len)
1039                                         goto leaf_item_out_of_bounce_error;
1040                                 btrfsic_read_from_block_data(
1041                                         sf->block_ctx, &root_item,
1042                                         root_item_offset,
1043                                         item_size);
1044                                 next_bytenr = btrfs_root_bytenr(&root_item);
1045
1046                                 sf->error =
1047                                     btrfsic_create_link_to_next_block(
1048                                                 state,
1049                                                 sf->block,
1050                                                 sf->block_ctx,
1051                                                 next_bytenr,
1052                                                 sf->limit_nesting,
1053                                                 &sf->next_block_ctx,
1054                                                 &sf->next_block,
1055                                                 force_iodone_flag,
1056                                                 &sf->num_copies,
1057                                                 &sf->mirror_num,
1058                                                 disk_key,
1059                                                 btrfs_root_generation(
1060                                                 &root_item));
1061                                 if (sf->error)
1062                                         goto one_stack_frame_backwards;
1063
1064                                 if (NULL != sf->next_block) {
1065                                         struct btrfs_header *const next_hdr =
1066                                             (struct btrfs_header *)
1067                                             sf->next_block_ctx.datav[0];
1068
1069                                         next_stack =
1070                                             btrfsic_stack_frame_alloc();
1071                                         if (NULL == next_stack) {
1072                                                 sf->error = -1;
1073                                                 btrfsic_release_block_ctx(
1074                                                                 &sf->
1075                                                                 next_block_ctx);
1076                                                 goto one_stack_frame_backwards;
1077                                         }
1078
1079                                         next_stack->i = -1;
1080                                         next_stack->block = sf->next_block;
1081                                         next_stack->block_ctx =
1082                                             &sf->next_block_ctx;
1083                                         next_stack->next_block = NULL;
1084                                         next_stack->hdr = next_hdr;
1085                                         next_stack->limit_nesting =
1086                                             sf->limit_nesting - 1;
1087                                         next_stack->prev = sf;
1088                                         sf = next_stack;
1089                                         goto continue_with_new_stack_frame;
1090                                 }
1091                         } else if (BTRFS_EXTENT_DATA_KEY == type &&
1092                                    state->include_extent_data) {
1093                                 sf->error = btrfsic_handle_extent_data(
1094                                                 state,
1095                                                 sf->block,
1096                                                 sf->block_ctx,
1097                                                 item_offset,
1098                                                 force_iodone_flag);
1099                                 if (sf->error)
1100                                         goto one_stack_frame_backwards;
1101                         }
1102
1103                         goto continue_with_current_leaf_stack_frame;
1104                 }
1105         } else {
1106                 struct btrfs_node *const nodehdr = (struct btrfs_node *)sf->hdr;
1107
1108                 if (-1 == sf->i) {
1109                         sf->nr = btrfs_stack_header_nritems(&nodehdr->header);
1110
1111                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1112                                 pr_info("node %llu level %d items %d generation %llu owner %llu\n",
1113                                        sf->block_ctx->start,
1114                                        nodehdr->header.level, sf->nr,
1115                                        btrfs_stack_header_generation(
1116                                        &nodehdr->header),
1117                                        btrfs_stack_header_owner(
1118                                        &nodehdr->header));
1119                 }
1120
1121 continue_with_current_node_stack_frame:
1122                 if (0 == sf->num_copies || sf->mirror_num > sf->num_copies) {
1123                         sf->i++;
1124                         sf->num_copies = 0;
1125                 }
1126
1127                 if (sf->i < sf->nr) {
1128                         struct btrfs_key_ptr key_ptr;
1129                         u32 key_ptr_offset;
1130                         u64 next_bytenr;
1131
1132                         key_ptr_offset = (uintptr_t)(nodehdr->ptrs + sf->i) -
1133                                           (uintptr_t)nodehdr;
1134                         if (key_ptr_offset + sizeof(struct btrfs_key_ptr) >
1135                             sf->block_ctx->len) {
1136                                 pr_info("btrfsic: node item out of bounce at logical %llu, dev %s\n",
1137                                        sf->block_ctx->start,
1138                                        sf->block_ctx->dev->name);
1139                                 goto one_stack_frame_backwards;
1140                         }
1141                         btrfsic_read_from_block_data(
1142                                 sf->block_ctx, &key_ptr, key_ptr_offset,
1143                                 sizeof(struct btrfs_key_ptr));
1144                         next_bytenr = btrfs_stack_key_blockptr(&key_ptr);
1145
1146                         sf->error = btrfsic_create_link_to_next_block(
1147                                         state,
1148                                         sf->block,
1149                                         sf->block_ctx,
1150                                         next_bytenr,
1151                                         sf->limit_nesting,
1152                                         &sf->next_block_ctx,
1153                                         &sf->next_block,
1154                                         force_iodone_flag,
1155                                         &sf->num_copies,
1156                                         &sf->mirror_num,
1157                                         &key_ptr.key,
1158                                         btrfs_stack_key_generation(&key_ptr));
1159                         if (sf->error)
1160                                 goto one_stack_frame_backwards;
1161
1162                         if (NULL != sf->next_block) {
1163                                 struct btrfs_header *const next_hdr =
1164                                     (struct btrfs_header *)
1165                                     sf->next_block_ctx.datav[0];
1166
1167                                 next_stack = btrfsic_stack_frame_alloc();
1168                                 if (NULL == next_stack) {
1169                                         sf->error = -1;
1170                                         goto one_stack_frame_backwards;
1171                                 }
1172
1173                                 next_stack->i = -1;
1174                                 next_stack->block = sf->next_block;
1175                                 next_stack->block_ctx = &sf->next_block_ctx;
1176                                 next_stack->next_block = NULL;
1177                                 next_stack->hdr = next_hdr;
1178                                 next_stack->limit_nesting =
1179                                     sf->limit_nesting - 1;
1180                                 next_stack->prev = sf;
1181                                 sf = next_stack;
1182                                 goto continue_with_new_stack_frame;
1183                         }
1184
1185                         goto continue_with_current_node_stack_frame;
1186                 }
1187         }
1188
1189 one_stack_frame_backwards:
1190         if (NULL != sf->prev) {
1191                 struct btrfsic_stack_frame *const prev = sf->prev;
1192
1193                 /* the one for the initial block is freed in the caller */
1194                 btrfsic_release_block_ctx(sf->block_ctx);
1195
1196                 if (sf->error) {
1197                         prev->error = sf->error;
1198                         btrfsic_stack_frame_free(sf);
1199                         sf = prev;
1200                         goto one_stack_frame_backwards;
1201                 }
1202
1203                 btrfsic_stack_frame_free(sf);
1204                 sf = prev;
1205                 goto continue_with_new_stack_frame;
1206         } else {
1207                 BUG_ON(&initial_stack_frame != sf);
1208         }
1209
1210         return sf->error;
1211 }
1212
1213 static void btrfsic_read_from_block_data(
1214         struct btrfsic_block_data_ctx *block_ctx,
1215         void *dstv, u32 offset, size_t len)
1216 {
1217         size_t cur;
1218         size_t offset_in_page;
1219         char *kaddr;
1220         char *dst = (char *)dstv;
1221         size_t start_offset = block_ctx->start & ((u64)PAGE_SIZE - 1);
1222         unsigned long i = (start_offset + offset) >> PAGE_SHIFT;
1223
1224         WARN_ON(offset + len > block_ctx->len);
1225         offset_in_page = (start_offset + offset) & (PAGE_SIZE - 1);
1226
1227         while (len > 0) {
1228                 cur = min(len, ((size_t)PAGE_SIZE - offset_in_page));
1229                 BUG_ON(i >= DIV_ROUND_UP(block_ctx->len, PAGE_SIZE));
1230                 kaddr = block_ctx->datav[i];
1231                 memcpy(dst, kaddr + offset_in_page, cur);
1232
1233                 dst += cur;
1234                 len -= cur;
1235                 offset_in_page = 0;
1236                 i++;
1237         }
1238 }
1239
1240 static int btrfsic_create_link_to_next_block(
1241                 struct btrfsic_state *state,
1242                 struct btrfsic_block *block,
1243                 struct btrfsic_block_data_ctx *block_ctx,
1244                 u64 next_bytenr,
1245                 int limit_nesting,
1246                 struct btrfsic_block_data_ctx *next_block_ctx,
1247                 struct btrfsic_block **next_blockp,
1248                 int force_iodone_flag,
1249                 int *num_copiesp, int *mirror_nump,
1250                 struct btrfs_disk_key *disk_key,
1251                 u64 parent_generation)
1252 {
1253         struct btrfs_fs_info *fs_info = state->fs_info;
1254         struct btrfsic_block *next_block = NULL;
1255         int ret;
1256         struct btrfsic_block_link *l;
1257         int did_alloc_block_link;
1258         int block_was_created;
1259
1260         *next_blockp = NULL;
1261         if (0 == *num_copiesp) {
1262                 *num_copiesp = btrfs_num_copies(fs_info, next_bytenr,
1263                                                 state->metablock_size);
1264                 if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
1265                         pr_info("num_copies(log_bytenr=%llu) = %d\n",
1266                                next_bytenr, *num_copiesp);
1267                 *mirror_nump = 1;
1268         }
1269
1270         if (*mirror_nump > *num_copiesp)
1271                 return 0;
1272
1273         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1274                 pr_info("btrfsic_create_link_to_next_block(mirror_num=%d)\n",
1275                        *mirror_nump);
1276         ret = btrfsic_map_block(state, next_bytenr,
1277                                 state->metablock_size,
1278                                 next_block_ctx, *mirror_nump);
1279         if (ret) {
1280                 pr_info("btrfsic: btrfsic_map_block(@%llu, mirror=%d) failed!\n",
1281                        next_bytenr, *mirror_nump);
1282                 btrfsic_release_block_ctx(next_block_ctx);
1283                 *next_blockp = NULL;
1284                 return -1;
1285         }
1286
1287         next_block = btrfsic_block_lookup_or_add(state,
1288                                                  next_block_ctx, "referenced ",
1289                                                  1, force_iodone_flag,
1290                                                  !force_iodone_flag,
1291                                                  *mirror_nump,
1292                                                  &block_was_created);
1293         if (NULL == next_block) {
1294                 btrfsic_release_block_ctx(next_block_ctx);
1295                 *next_blockp = NULL;
1296                 return -1;
1297         }
1298         if (block_was_created) {
1299                 l = NULL;
1300                 next_block->generation = BTRFSIC_GENERATION_UNKNOWN;
1301         } else {
1302                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE) {
1303                         if (next_block->logical_bytenr != next_bytenr &&
1304                             !(!next_block->is_metadata &&
1305                               0 == next_block->logical_bytenr))
1306                                 pr_info("Referenced block @%llu (%s/%llu/%d) found in hash table, %c, bytenr mismatch (!= stored %llu).\n",
1307                                        next_bytenr, next_block_ctx->dev->name,
1308                                        next_block_ctx->dev_bytenr, *mirror_nump,
1309                                        btrfsic_get_block_type(state,
1310                                                               next_block),
1311                                        next_block->logical_bytenr);
1312                         else
1313                                 pr_info("Referenced block @%llu (%s/%llu/%d) found in hash table, %c.\n",
1314                                        next_bytenr, next_block_ctx->dev->name,
1315                                        next_block_ctx->dev_bytenr, *mirror_nump,
1316                                        btrfsic_get_block_type(state,
1317                                                               next_block));
1318                 }
1319                 next_block->logical_bytenr = next_bytenr;
1320
1321                 next_block->mirror_num = *mirror_nump;
1322                 l = btrfsic_block_link_hashtable_lookup(
1323                                 next_block_ctx->dev->bdev,
1324                                 next_block_ctx->dev_bytenr,
1325                                 block_ctx->dev->bdev,
1326                                 block_ctx->dev_bytenr,
1327                                 &state->block_link_hashtable);
1328         }
1329
1330         next_block->disk_key = *disk_key;
1331         if (NULL == l) {
1332                 l = btrfsic_block_link_alloc();
1333                 if (NULL == l) {
1334                         pr_info("btrfsic: error, kmalloc failed!\n");
1335                         btrfsic_release_block_ctx(next_block_ctx);
1336                         *next_blockp = NULL;
1337                         return -1;
1338                 }
1339
1340                 did_alloc_block_link = 1;
1341                 l->block_ref_to = next_block;
1342                 l->block_ref_from = block;
1343                 l->ref_cnt = 1;
1344                 l->parent_generation = parent_generation;
1345
1346                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1347                         btrfsic_print_add_link(state, l);
1348
1349                 list_add(&l->node_ref_to, &block->ref_to_list);
1350                 list_add(&l->node_ref_from, &next_block->ref_from_list);
1351
1352                 btrfsic_block_link_hashtable_add(l,
1353                                                  &state->block_link_hashtable);
1354         } else {
1355                 did_alloc_block_link = 0;
1356                 if (0 == limit_nesting) {
1357                         l->ref_cnt++;
1358                         l->parent_generation = parent_generation;
1359                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1360                                 btrfsic_print_add_link(state, l);
1361                 }
1362         }
1363
1364         if (limit_nesting > 0 && did_alloc_block_link) {
1365                 ret = btrfsic_read_block(state, next_block_ctx);
1366                 if (ret < (int)next_block_ctx->len) {
1367                         pr_info("btrfsic: read block @logical %llu failed!\n",
1368                                next_bytenr);
1369                         btrfsic_release_block_ctx(next_block_ctx);
1370                         *next_blockp = NULL;
1371                         return -1;
1372                 }
1373
1374                 *next_blockp = next_block;
1375         } else {
1376                 *next_blockp = NULL;
1377         }
1378         (*mirror_nump)++;
1379
1380         return 0;
1381 }
1382
1383 static int btrfsic_handle_extent_data(
1384                 struct btrfsic_state *state,
1385                 struct btrfsic_block *block,
1386                 struct btrfsic_block_data_ctx *block_ctx,
1387                 u32 item_offset, int force_iodone_flag)
1388 {
1389         struct btrfs_fs_info *fs_info = state->fs_info;
1390         struct btrfs_file_extent_item file_extent_item;
1391         u64 file_extent_item_offset;
1392         u64 next_bytenr;
1393         u64 num_bytes;
1394         u64 generation;
1395         struct btrfsic_block_link *l;
1396         int ret;
1397
1398         file_extent_item_offset = offsetof(struct btrfs_leaf, items) +
1399                                   item_offset;
1400         if (file_extent_item_offset +
1401             offsetof(struct btrfs_file_extent_item, disk_num_bytes) >
1402             block_ctx->len) {
1403                 pr_info("btrfsic: file item out of bounce at logical %llu, dev %s\n",
1404                        block_ctx->start, block_ctx->dev->name);
1405                 return -1;
1406         }
1407
1408         btrfsic_read_from_block_data(block_ctx, &file_extent_item,
1409                 file_extent_item_offset,
1410                 offsetof(struct btrfs_file_extent_item, disk_num_bytes));
1411         if (BTRFS_FILE_EXTENT_REG != file_extent_item.type ||
1412             btrfs_stack_file_extent_disk_bytenr(&file_extent_item) == 0) {
1413                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERY_VERBOSE)
1414                         pr_info("extent_data: type %u, disk_bytenr = %llu\n",
1415                                file_extent_item.type,
1416                                btrfs_stack_file_extent_disk_bytenr(
1417                                &file_extent_item));
1418                 return 0;
1419         }
1420
1421         if (file_extent_item_offset + sizeof(struct btrfs_file_extent_item) >
1422             block_ctx->len) {
1423                 pr_info("btrfsic: file item out of bounce at logical %llu, dev %s\n",
1424                        block_ctx->start, block_ctx->dev->name);
1425                 return -1;
1426         }
1427         btrfsic_read_from_block_data(block_ctx, &file_extent_item,
1428                                      file_extent_item_offset,
1429                                      sizeof(struct btrfs_file_extent_item));
1430         next_bytenr = btrfs_stack_file_extent_disk_bytenr(&file_extent_item);
1431         if (btrfs_stack_file_extent_compression(&file_extent_item) ==
1432             BTRFS_COMPRESS_NONE) {
1433                 next_bytenr += btrfs_stack_file_extent_offset(&file_extent_item);
1434                 num_bytes = btrfs_stack_file_extent_num_bytes(&file_extent_item);
1435         } else {
1436                 num_bytes = btrfs_stack_file_extent_disk_num_bytes(&file_extent_item);
1437         }
1438         generation = btrfs_stack_file_extent_generation(&file_extent_item);
1439
1440         if (state->print_mask & BTRFSIC_PRINT_MASK_VERY_VERBOSE)
1441                 pr_info("extent_data: type %u, disk_bytenr = %llu, offset = %llu, num_bytes = %llu\n",
1442                        file_extent_item.type,
1443                        btrfs_stack_file_extent_disk_bytenr(&file_extent_item),
1444                        btrfs_stack_file_extent_offset(&file_extent_item),
1445                        num_bytes);
1446         while (num_bytes > 0) {
1447                 u32 chunk_len;
1448                 int num_copies;
1449                 int mirror_num;
1450
1451                 if (num_bytes > state->datablock_size)
1452                         chunk_len = state->datablock_size;
1453                 else
1454                         chunk_len = num_bytes;
1455
1456                 num_copies = btrfs_num_copies(fs_info, next_bytenr,
1457                                               state->datablock_size);
1458                 if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
1459                         pr_info("num_copies(log_bytenr=%llu) = %d\n",
1460                                next_bytenr, num_copies);
1461                 for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
1462                         struct btrfsic_block_data_ctx next_block_ctx;
1463                         struct btrfsic_block *next_block;
1464                         int block_was_created;
1465
1466                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1467                                 pr_info("btrfsic_handle_extent_data(mirror_num=%d)\n",
1468                                         mirror_num);
1469                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERY_VERBOSE)
1470                                 pr_info("\tdisk_bytenr = %llu, num_bytes %u\n",
1471                                        next_bytenr, chunk_len);
1472                         ret = btrfsic_map_block(state, next_bytenr,
1473                                                 chunk_len, &next_block_ctx,
1474                                                 mirror_num);
1475                         if (ret) {
1476                                 pr_info("btrfsic: btrfsic_map_block(@%llu, mirror=%d) failed!\n",
1477                                        next_bytenr, mirror_num);
1478                                 return -1;
1479                         }
1480
1481                         next_block = btrfsic_block_lookup_or_add(
1482                                         state,
1483                                         &next_block_ctx,
1484                                         "referenced ",
1485                                         0,
1486                                         force_iodone_flag,
1487                                         !force_iodone_flag,
1488                                         mirror_num,
1489                                         &block_was_created);
1490                         if (NULL == next_block) {
1491                                 pr_info("btrfsic: error, kmalloc failed!\n");
1492                                 btrfsic_release_block_ctx(&next_block_ctx);
1493                                 return -1;
1494                         }
1495                         if (!block_was_created) {
1496                                 if ((state->print_mask &
1497                                      BTRFSIC_PRINT_MASK_VERBOSE) &&
1498                                     next_block->logical_bytenr != next_bytenr &&
1499                                     !(!next_block->is_metadata &&
1500                                       0 == next_block->logical_bytenr)) {
1501                                         pr_info("Referenced block @%llu (%s/%llu/%d) found in hash table, D, bytenr mismatch (!= stored %llu).\n",
1502                                                next_bytenr,
1503                                                next_block_ctx.dev->name,
1504                                                next_block_ctx.dev_bytenr,
1505                                                mirror_num,
1506                                                next_block->logical_bytenr);
1507                                 }
1508                                 next_block->logical_bytenr = next_bytenr;
1509                                 next_block->mirror_num = mirror_num;
1510                         }
1511
1512                         l = btrfsic_block_link_lookup_or_add(state,
1513                                                              &next_block_ctx,
1514                                                              next_block, block,
1515                                                              generation);
1516                         btrfsic_release_block_ctx(&next_block_ctx);
1517                         if (NULL == l)
1518                                 return -1;
1519                 }
1520
1521                 next_bytenr += chunk_len;
1522                 num_bytes -= chunk_len;
1523         }
1524
1525         return 0;
1526 }
1527
1528 static int btrfsic_map_block(struct btrfsic_state *state, u64 bytenr, u32 len,
1529                              struct btrfsic_block_data_ctx *block_ctx_out,
1530                              int mirror_num)
1531 {
1532         struct btrfs_fs_info *fs_info = state->fs_info;
1533         int ret;
1534         u64 length;
1535         struct btrfs_bio *multi = NULL;
1536         struct btrfs_device *device;
1537
1538         length = len;
1539         ret = btrfs_map_block(fs_info, BTRFS_MAP_READ,
1540                               bytenr, &length, &multi, mirror_num);
1541
1542         if (ret) {
1543                 block_ctx_out->start = 0;
1544                 block_ctx_out->dev_bytenr = 0;
1545                 block_ctx_out->len = 0;
1546                 block_ctx_out->dev = NULL;
1547                 block_ctx_out->datav = NULL;
1548                 block_ctx_out->pagev = NULL;
1549                 block_ctx_out->mem_to_free = NULL;
1550
1551                 return ret;
1552         }
1553
1554         device = multi->stripes[0].dev;
1555         block_ctx_out->dev = btrfsic_dev_state_lookup(device->bdev->bd_dev);
1556         block_ctx_out->dev_bytenr = multi->stripes[0].physical;
1557         block_ctx_out->start = bytenr;
1558         block_ctx_out->len = len;
1559         block_ctx_out->datav = NULL;
1560         block_ctx_out->pagev = NULL;
1561         block_ctx_out->mem_to_free = NULL;
1562
1563         kfree(multi);
1564         if (NULL == block_ctx_out->dev) {
1565                 ret = -ENXIO;
1566                 pr_info("btrfsic: error, cannot lookup dev (#1)!\n");
1567         }
1568
1569         return ret;
1570 }
1571
1572 static void btrfsic_release_block_ctx(struct btrfsic_block_data_ctx *block_ctx)
1573 {
1574         if (block_ctx->mem_to_free) {
1575                 unsigned int num_pages;
1576
1577                 BUG_ON(!block_ctx->datav);
1578                 BUG_ON(!block_ctx->pagev);
1579                 num_pages = (block_ctx->len + (u64)PAGE_SIZE - 1) >>
1580                             PAGE_SHIFT;
1581                 while (num_pages > 0) {
1582                         num_pages--;
1583                         if (block_ctx->datav[num_pages]) {
1584                                 kunmap(block_ctx->pagev[num_pages]);
1585                                 block_ctx->datav[num_pages] = NULL;
1586                         }
1587                         if (block_ctx->pagev[num_pages]) {
1588                                 __free_page(block_ctx->pagev[num_pages]);
1589                                 block_ctx->pagev[num_pages] = NULL;
1590                         }
1591                 }
1592
1593                 kfree(block_ctx->mem_to_free);
1594                 block_ctx->mem_to_free = NULL;
1595                 block_ctx->pagev = NULL;
1596                 block_ctx->datav = NULL;
1597         }
1598 }
1599
1600 static int btrfsic_read_block(struct btrfsic_state *state,
1601                               struct btrfsic_block_data_ctx *block_ctx)
1602 {
1603         unsigned int num_pages;
1604         unsigned int i;
1605         u64 dev_bytenr;
1606         int ret;
1607
1608         BUG_ON(block_ctx->datav);
1609         BUG_ON(block_ctx->pagev);
1610         BUG_ON(block_ctx->mem_to_free);
1611         if (block_ctx->dev_bytenr & ((u64)PAGE_SIZE - 1)) {
1612                 pr_info("btrfsic: read_block() with unaligned bytenr %llu\n",
1613                        block_ctx->dev_bytenr);
1614                 return -1;
1615         }
1616
1617         num_pages = (block_ctx->len + (u64)PAGE_SIZE - 1) >>
1618                     PAGE_SHIFT;
1619         block_ctx->mem_to_free = kzalloc((sizeof(*block_ctx->datav) +
1620                                           sizeof(*block_ctx->pagev)) *
1621                                          num_pages, GFP_NOFS);
1622         if (!block_ctx->mem_to_free)
1623                 return -ENOMEM;
1624         block_ctx->datav = block_ctx->mem_to_free;
1625         block_ctx->pagev = (struct page **)(block_ctx->datav + num_pages);
1626         for (i = 0; i < num_pages; i++) {
1627                 block_ctx->pagev[i] = alloc_page(GFP_NOFS);
1628                 if (!block_ctx->pagev[i])
1629                         return -1;
1630         }
1631
1632         dev_bytenr = block_ctx->dev_bytenr;
1633         for (i = 0; i < num_pages;) {
1634                 struct bio *bio;
1635                 unsigned int j;
1636
1637                 bio = btrfs_io_bio_alloc(num_pages - i);
1638                 bio_set_dev(bio, block_ctx->dev->bdev);
1639                 bio->bi_iter.bi_sector = dev_bytenr >> 9;
1640                 bio_set_op_attrs(bio, REQ_OP_READ, 0);
1641
1642                 for (j = i; j < num_pages; j++) {
1643                         ret = bio_add_page(bio, block_ctx->pagev[j],
1644                                            PAGE_SIZE, 0);
1645                         if (PAGE_SIZE != ret)
1646                                 break;
1647                 }
1648                 if (j == i) {
1649                         pr_info("btrfsic: error, failed to add a single page!\n");
1650                         return -1;
1651                 }
1652                 if (submit_bio_wait(bio)) {
1653                         pr_info("btrfsic: read error at logical %llu dev %s!\n",
1654                                block_ctx->start, block_ctx->dev->name);
1655                         bio_put(bio);
1656                         return -1;
1657                 }
1658                 bio_put(bio);
1659                 dev_bytenr += (j - i) * PAGE_SIZE;
1660                 i = j;
1661         }
1662         for (i = 0; i < num_pages; i++)
1663                 block_ctx->datav[i] = kmap(block_ctx->pagev[i]);
1664
1665         return block_ctx->len;
1666 }
1667
1668 static void btrfsic_dump_database(struct btrfsic_state *state)
1669 {
1670         const struct btrfsic_block *b_all;
1671
1672         BUG_ON(NULL == state);
1673
1674         pr_info("all_blocks_list:\n");
1675         list_for_each_entry(b_all, &state->all_blocks_list, all_blocks_node) {
1676                 const struct btrfsic_block_link *l;
1677
1678                 pr_info("%c-block @%llu (%s/%llu/%d)\n",
1679                        btrfsic_get_block_type(state, b_all),
1680                        b_all->logical_bytenr, b_all->dev_state->name,
1681                        b_all->dev_bytenr, b_all->mirror_num);
1682
1683                 list_for_each_entry(l, &b_all->ref_to_list, node_ref_to) {
1684                         pr_info(" %c @%llu (%s/%llu/%d) refers %u* to %c @%llu (%s/%llu/%d)\n",
1685                                btrfsic_get_block_type(state, b_all),
1686                                b_all->logical_bytenr, b_all->dev_state->name,
1687                                b_all->dev_bytenr, b_all->mirror_num,
1688                                l->ref_cnt,
1689                                btrfsic_get_block_type(state, l->block_ref_to),
1690                                l->block_ref_to->logical_bytenr,
1691                                l->block_ref_to->dev_state->name,
1692                                l->block_ref_to->dev_bytenr,
1693                                l->block_ref_to->mirror_num);
1694                 }
1695
1696                 list_for_each_entry(l, &b_all->ref_from_list, node_ref_from) {
1697                         pr_info(" %c @%llu (%s/%llu/%d) is ref %u* from %c @%llu (%s/%llu/%d)\n",
1698                                btrfsic_get_block_type(state, b_all),
1699                                b_all->logical_bytenr, b_all->dev_state->name,
1700                                b_all->dev_bytenr, b_all->mirror_num,
1701                                l->ref_cnt,
1702                                btrfsic_get_block_type(state, l->block_ref_from),
1703                                l->block_ref_from->logical_bytenr,
1704                                l->block_ref_from->dev_state->name,
1705                                l->block_ref_from->dev_bytenr,
1706                                l->block_ref_from->mirror_num);
1707                 }
1708
1709                 pr_info("\n");
1710         }
1711 }
1712
1713 /*
1714  * Test whether the disk block contains a tree block (leaf or node)
1715  * (note that this test fails for the super block)
1716  */
1717 static int btrfsic_test_for_metadata(struct btrfsic_state *state,
1718                                      char **datav, unsigned int num_pages)
1719 {
1720         struct btrfs_fs_info *fs_info = state->fs_info;
1721         struct btrfs_header *h;
1722         u8 csum[BTRFS_CSUM_SIZE];
1723         u32 crc = ~(u32)0;
1724         unsigned int i;
1725
1726         if (num_pages * PAGE_SIZE < state->metablock_size)
1727                 return 1; /* not metadata */
1728         num_pages = state->metablock_size >> PAGE_SHIFT;
1729         h = (struct btrfs_header *)datav[0];
1730
1731         if (memcmp(h->fsid, fs_info->fsid, BTRFS_FSID_SIZE))
1732                 return 1;
1733
1734         for (i = 0; i < num_pages; i++) {
1735                 u8 *data = i ? datav[i] : (datav[i] + BTRFS_CSUM_SIZE);
1736                 size_t sublen = i ? PAGE_SIZE :
1737                                     (PAGE_SIZE - BTRFS_CSUM_SIZE);
1738
1739                 crc = crc32c(crc, data, sublen);
1740         }
1741         btrfs_csum_final(crc, csum);
1742         if (memcmp(csum, h->csum, state->csum_size))
1743                 return 1;
1744
1745         return 0; /* is metadata */
1746 }
1747
1748 static void btrfsic_process_written_block(struct btrfsic_dev_state *dev_state,
1749                                           u64 dev_bytenr, char **mapped_datav,
1750                                           unsigned int num_pages,
1751                                           struct bio *bio, int *bio_is_patched,
1752                                           struct buffer_head *bh,
1753                                           int submit_bio_bh_rw)
1754 {
1755         int is_metadata;
1756         struct btrfsic_block *block;
1757         struct btrfsic_block_data_ctx block_ctx;
1758         int ret;
1759         struct btrfsic_state *state = dev_state->state;
1760         struct block_device *bdev = dev_state->bdev;
1761         unsigned int processed_len;
1762
1763         if (NULL != bio_is_patched)
1764                 *bio_is_patched = 0;
1765
1766 again:
1767         if (num_pages == 0)
1768                 return;
1769
1770         processed_len = 0;
1771         is_metadata = (0 == btrfsic_test_for_metadata(state, mapped_datav,
1772                                                       num_pages));
1773
1774         block = btrfsic_block_hashtable_lookup(bdev, dev_bytenr,
1775                                                &state->block_hashtable);
1776         if (NULL != block) {
1777                 u64 bytenr = 0;
1778                 struct btrfsic_block_link *l, *tmp;
1779
1780                 if (block->is_superblock) {
1781                         bytenr = btrfs_super_bytenr((struct btrfs_super_block *)
1782                                                     mapped_datav[0]);
1783                         if (num_pages * PAGE_SIZE <
1784                             BTRFS_SUPER_INFO_SIZE) {
1785                                 pr_info("btrfsic: cannot work with too short bios!\n");
1786                                 return;
1787                         }
1788                         is_metadata = 1;
1789                         BUG_ON(BTRFS_SUPER_INFO_SIZE & (PAGE_SIZE - 1));
1790                         processed_len = BTRFS_SUPER_INFO_SIZE;
1791                         if (state->print_mask &
1792                             BTRFSIC_PRINT_MASK_TREE_BEFORE_SB_WRITE) {
1793                                 pr_info("[before new superblock is written]:\n");
1794                                 btrfsic_dump_tree_sub(state, block, 0);
1795                         }
1796                 }
1797                 if (is_metadata) {
1798                         if (!block->is_superblock) {
1799                                 if (num_pages * PAGE_SIZE <
1800                                     state->metablock_size) {
1801                                         pr_info("btrfsic: cannot work with too short bios!\n");
1802                                         return;
1803                                 }
1804                                 processed_len = state->metablock_size;
1805                                 bytenr = btrfs_stack_header_bytenr(
1806                                                 (struct btrfs_header *)
1807                                                 mapped_datav[0]);
1808                                 btrfsic_cmp_log_and_dev_bytenr(state, bytenr,
1809                                                                dev_state,
1810                                                                dev_bytenr);
1811                         }
1812                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE) {
1813                                 if (block->logical_bytenr != bytenr &&
1814                                     !(!block->is_metadata &&
1815                                       block->logical_bytenr == 0))
1816                                         pr_info("Written block @%llu (%s/%llu/%d) found in hash table, %c, bytenr mismatch (!= stored %llu).\n",
1817                                                bytenr, dev_state->name,
1818                                                dev_bytenr,
1819                                                block->mirror_num,
1820                                                btrfsic_get_block_type(state,
1821                                                                       block),
1822                                                block->logical_bytenr);
1823                                 else
1824                                         pr_info("Written block @%llu (%s/%llu/%d) found in hash table, %c.\n",
1825                                                bytenr, dev_state->name,
1826                                                dev_bytenr, block->mirror_num,
1827                                                btrfsic_get_block_type(state,
1828                                                                       block));
1829                         }
1830                         block->logical_bytenr = bytenr;
1831                 } else {
1832                         if (num_pages * PAGE_SIZE <
1833                             state->datablock_size) {
1834                                 pr_info("btrfsic: cannot work with too short bios!\n");
1835                                 return;
1836                         }
1837                         processed_len = state->datablock_size;
1838                         bytenr = block->logical_bytenr;
1839                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1840                                 pr_info("Written block @%llu (%s/%llu/%d) found in hash table, %c.\n",
1841                                        bytenr, dev_state->name, dev_bytenr,
1842                                        block->mirror_num,
1843                                        btrfsic_get_block_type(state, block));
1844                 }
1845
1846                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1847                         pr_info("ref_to_list: %cE, ref_from_list: %cE\n",
1848                                list_empty(&block->ref_to_list) ? ' ' : '!',
1849                                list_empty(&block->ref_from_list) ? ' ' : '!');
1850                 if (btrfsic_is_block_ref_by_superblock(state, block, 0)) {
1851                         pr_info("btrfs: attempt to overwrite %c-block @%llu (%s/%llu/%d), old(gen=%llu, objectid=%llu, type=%d, offset=%llu), new(gen=%llu), which is referenced by most recent superblock (superblockgen=%llu)!\n",
1852                                btrfsic_get_block_type(state, block), bytenr,
1853                                dev_state->name, dev_bytenr, block->mirror_num,
1854                                block->generation,
1855                                btrfs_disk_key_objectid(&block->disk_key),
1856                                block->disk_key.type,
1857                                btrfs_disk_key_offset(&block->disk_key),
1858                                btrfs_stack_header_generation(
1859                                        (struct btrfs_header *) mapped_datav[0]),
1860                                state->max_superblock_generation);
1861                         btrfsic_dump_tree(state);
1862                 }
1863
1864                 if (!block->is_iodone && !block->never_written) {
1865                         pr_info("btrfs: attempt to overwrite %c-block @%llu (%s/%llu/%d), oldgen=%llu, newgen=%llu, which is not yet iodone!\n",
1866                                btrfsic_get_block_type(state, block), bytenr,
1867                                dev_state->name, dev_bytenr, block->mirror_num,
1868                                block->generation,
1869                                btrfs_stack_header_generation(
1870                                        (struct btrfs_header *)
1871                                        mapped_datav[0]));
1872                         /* it would not be safe to go on */
1873                         btrfsic_dump_tree(state);
1874                         goto continue_loop;
1875                 }
1876
1877                 /*
1878                  * Clear all references of this block. Do not free
1879                  * the block itself even if is not referenced anymore
1880                  * because it still carries valuable information
1881                  * like whether it was ever written and IO completed.
1882                  */
1883                 list_for_each_entry_safe(l, tmp, &block->ref_to_list,
1884                                          node_ref_to) {
1885                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1886                                 btrfsic_print_rem_link(state, l);
1887                         l->ref_cnt--;
1888                         if (0 == l->ref_cnt) {
1889                                 list_del(&l->node_ref_to);
1890                                 list_del(&l->node_ref_from);
1891                                 btrfsic_block_link_hashtable_remove(l);
1892                                 btrfsic_block_link_free(l);
1893                         }
1894                 }
1895
1896                 block_ctx.dev = dev_state;
1897                 block_ctx.dev_bytenr = dev_bytenr;
1898                 block_ctx.start = bytenr;
1899                 block_ctx.len = processed_len;
1900                 block_ctx.pagev = NULL;
1901                 block_ctx.mem_to_free = NULL;
1902                 block_ctx.datav = mapped_datav;
1903
1904                 if (is_metadata || state->include_extent_data) {
1905                         block->never_written = 0;
1906                         block->iodone_w_error = 0;
1907                         if (NULL != bio) {
1908                                 block->is_iodone = 0;
1909                                 BUG_ON(NULL == bio_is_patched);
1910                                 if (!*bio_is_patched) {
1911                                         block->orig_bio_bh_private =
1912                                             bio->bi_private;
1913                                         block->orig_bio_bh_end_io.bio =
1914                                             bio->bi_end_io;
1915                                         block->next_in_same_bio = NULL;
1916                                         bio->bi_private = block;
1917                                         bio->bi_end_io = btrfsic_bio_end_io;
1918                                         *bio_is_patched = 1;
1919                                 } else {
1920                                         struct btrfsic_block *chained_block =
1921                                             (struct btrfsic_block *)
1922                                             bio->bi_private;
1923
1924                                         BUG_ON(NULL == chained_block);
1925                                         block->orig_bio_bh_private =
1926                                             chained_block->orig_bio_bh_private;
1927                                         block->orig_bio_bh_end_io.bio =
1928                                             chained_block->orig_bio_bh_end_io.
1929                                             bio;
1930                                         block->next_in_same_bio = chained_block;
1931                                         bio->bi_private = block;
1932                                 }
1933                         } else if (NULL != bh) {
1934                                 block->is_iodone = 0;
1935                                 block->orig_bio_bh_private = bh->b_private;
1936                                 block->orig_bio_bh_end_io.bh = bh->b_end_io;
1937                                 block->next_in_same_bio = NULL;
1938                                 bh->b_private = block;
1939                                 bh->b_end_io = btrfsic_bh_end_io;
1940                         } else {
1941                                 block->is_iodone = 1;
1942                                 block->orig_bio_bh_private = NULL;
1943                                 block->orig_bio_bh_end_io.bio = NULL;
1944                                 block->next_in_same_bio = NULL;
1945                         }
1946                 }
1947
1948                 block->flush_gen = dev_state->last_flush_gen + 1;
1949                 block->submit_bio_bh_rw = submit_bio_bh_rw;
1950                 if (is_metadata) {
1951                         block->logical_bytenr = bytenr;
1952                         block->is_metadata = 1;
1953                         if (block->is_superblock) {
1954                                 BUG_ON(PAGE_SIZE !=
1955                                        BTRFS_SUPER_INFO_SIZE);
1956                                 ret = btrfsic_process_written_superblock(
1957                                                 state,
1958                                                 block,
1959                                                 (struct btrfs_super_block *)
1960                                                 mapped_datav[0]);
1961                                 if (state->print_mask &
1962                                     BTRFSIC_PRINT_MASK_TREE_AFTER_SB_WRITE) {
1963                                         pr_info("[after new superblock is written]:\n");
1964                                         btrfsic_dump_tree_sub(state, block, 0);
1965                                 }
1966                         } else {
1967                                 block->mirror_num = 0;  /* unknown */
1968                                 ret = btrfsic_process_metablock(
1969                                                 state,
1970                                                 block,
1971                                                 &block_ctx,
1972                                                 0, 0);
1973                         }
1974                         if (ret)
1975                                 pr_info("btrfsic: btrfsic_process_metablock(root @%llu) failed!\n",
1976                                        dev_bytenr);
1977                 } else {
1978                         block->is_metadata = 0;
1979                         block->mirror_num = 0;  /* unknown */
1980                         block->generation = BTRFSIC_GENERATION_UNKNOWN;
1981                         if (!state->include_extent_data
1982                             && list_empty(&block->ref_from_list)) {
1983                                 /*
1984                                  * disk block is overwritten with extent
1985                                  * data (not meta data) and we are configured
1986                                  * to not include extent data: take the
1987                                  * chance and free the block's memory
1988                                  */
1989                                 btrfsic_block_hashtable_remove(block);
1990                                 list_del(&block->all_blocks_node);
1991                                 btrfsic_block_free(block);
1992                         }
1993                 }
1994                 btrfsic_release_block_ctx(&block_ctx);
1995         } else {
1996                 /* block has not been found in hash table */
1997                 u64 bytenr;
1998
1999                 if (!is_metadata) {
2000                         processed_len = state->datablock_size;
2001                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2002                                 pr_info("Written block (%s/%llu/?) !found in hash table, D.\n",
2003                                        dev_state->name, dev_bytenr);
2004                         if (!state->include_extent_data) {
2005                                 /* ignore that written D block */
2006                                 goto continue_loop;
2007                         }
2008
2009                         /* this is getting ugly for the
2010                          * include_extent_data case... */
2011                         bytenr = 0;     /* unknown */
2012                 } else {
2013                         processed_len = state->metablock_size;
2014                         bytenr = btrfs_stack_header_bytenr(
2015                                         (struct btrfs_header *)
2016                                         mapped_datav[0]);
2017                         btrfsic_cmp_log_and_dev_bytenr(state, bytenr, dev_state,
2018                                                        dev_bytenr);
2019                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2020                                 pr_info("Written block @%llu (%s/%llu/?) !found in hash table, M.\n",
2021                                        bytenr, dev_state->name, dev_bytenr);
2022                 }
2023
2024                 block_ctx.dev = dev_state;
2025                 block_ctx.dev_bytenr = dev_bytenr;
2026                 block_ctx.start = bytenr;
2027                 block_ctx.len = processed_len;
2028                 block_ctx.pagev = NULL;
2029                 block_ctx.mem_to_free = NULL;
2030                 block_ctx.datav = mapped_datav;
2031
2032                 block = btrfsic_block_alloc();
2033                 if (NULL == block) {
2034                         pr_info("btrfsic: error, kmalloc failed!\n");
2035                         btrfsic_release_block_ctx(&block_ctx);
2036                         goto continue_loop;
2037                 }
2038                 block->dev_state = dev_state;
2039                 block->dev_bytenr = dev_bytenr;
2040                 block->logical_bytenr = bytenr;
2041                 block->is_metadata = is_metadata;
2042                 block->never_written = 0;
2043                 block->iodone_w_error = 0;
2044                 block->mirror_num = 0;  /* unknown */
2045                 block->flush_gen = dev_state->last_flush_gen + 1;
2046                 block->submit_bio_bh_rw = submit_bio_bh_rw;
2047                 if (NULL != bio) {
2048                         block->is_iodone = 0;
2049                         BUG_ON(NULL == bio_is_patched);
2050                         if (!*bio_is_patched) {
2051                                 block->orig_bio_bh_private = bio->bi_private;
2052                                 block->orig_bio_bh_end_io.bio = bio->bi_end_io;
2053                                 block->next_in_same_bio = NULL;
2054                                 bio->bi_private = block;
2055                                 bio->bi_end_io = btrfsic_bio_end_io;
2056                                 *bio_is_patched = 1;
2057                         } else {
2058                                 struct btrfsic_block *chained_block =
2059                                     (struct btrfsic_block *)
2060                                     bio->bi_private;
2061
2062                                 BUG_ON(NULL == chained_block);
2063                                 block->orig_bio_bh_private =
2064                                     chained_block->orig_bio_bh_private;
2065                                 block->orig_bio_bh_end_io.bio =
2066                                     chained_block->orig_bio_bh_end_io.bio;
2067                                 block->next_in_same_bio = chained_block;
2068                                 bio->bi_private = block;
2069                         }
2070                 } else if (NULL != bh) {
2071                         block->is_iodone = 0;
2072                         block->orig_bio_bh_private = bh->b_private;
2073                         block->orig_bio_bh_end_io.bh = bh->b_end_io;
2074                         block->next_in_same_bio = NULL;
2075                         bh->b_private = block;
2076                         bh->b_end_io = btrfsic_bh_end_io;
2077                 } else {
2078                         block->is_iodone = 1;
2079                         block->orig_bio_bh_private = NULL;
2080                         block->orig_bio_bh_end_io.bio = NULL;
2081                         block->next_in_same_bio = NULL;
2082                 }
2083                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2084                         pr_info("New written %c-block @%llu (%s/%llu/%d)\n",
2085                                is_metadata ? 'M' : 'D',
2086                                block->logical_bytenr, block->dev_state->name,
2087                                block->dev_bytenr, block->mirror_num);
2088                 list_add(&block->all_blocks_node, &state->all_blocks_list);
2089                 btrfsic_block_hashtable_add(block, &state->block_hashtable);
2090
2091                 if (is_metadata) {
2092                         ret = btrfsic_process_metablock(state, block,
2093                                                         &block_ctx, 0, 0);
2094                         if (ret)
2095                                 pr_info("btrfsic: process_metablock(root @%llu) failed!\n",
2096                                        dev_bytenr);
2097                 }
2098                 btrfsic_release_block_ctx(&block_ctx);
2099         }
2100
2101 continue_loop:
2102         BUG_ON(!processed_len);
2103         dev_bytenr += processed_len;
2104         mapped_datav += processed_len >> PAGE_SHIFT;
2105         num_pages -= processed_len >> PAGE_SHIFT;
2106         goto again;
2107 }
2108
2109 static void btrfsic_bio_end_io(struct bio *bp)
2110 {
2111         struct btrfsic_block *block = (struct btrfsic_block *)bp->bi_private;
2112         int iodone_w_error;
2113
2114         /* mutex is not held! This is not save if IO is not yet completed
2115          * on umount */
2116         iodone_w_error = 0;
2117         if (bp->bi_status)
2118                 iodone_w_error = 1;
2119
2120         BUG_ON(NULL == block);
2121         bp->bi_private = block->orig_bio_bh_private;
2122         bp->bi_end_io = block->orig_bio_bh_end_io.bio;
2123
2124         do {
2125                 struct btrfsic_block *next_block;
2126                 struct btrfsic_dev_state *const dev_state = block->dev_state;
2127
2128                 if ((dev_state->state->print_mask &
2129                      BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2130                         pr_info("bio_end_io(err=%d) for %c @%llu (%s/%llu/%d)\n",
2131                                bp->bi_status,
2132                                btrfsic_get_block_type(dev_state->state, block),
2133                                block->logical_bytenr, dev_state->name,
2134                                block->dev_bytenr, block->mirror_num);
2135                 next_block = block->next_in_same_bio;
2136                 block->iodone_w_error = iodone_w_error;
2137                 if (block->submit_bio_bh_rw & REQ_PREFLUSH) {
2138                         dev_state->last_flush_gen++;
2139                         if ((dev_state->state->print_mask &
2140                              BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2141                                 pr_info("bio_end_io() new %s flush_gen=%llu\n",
2142                                        dev_state->name,
2143                                        dev_state->last_flush_gen);
2144                 }
2145                 if (block->submit_bio_bh_rw & REQ_FUA)
2146                         block->flush_gen = 0; /* FUA completed means block is
2147                                                * on disk */
2148                 block->is_iodone = 1; /* for FLUSH, this releases the block */
2149                 block = next_block;
2150         } while (NULL != block);
2151
2152         bp->bi_end_io(bp);
2153 }
2154
2155 static void btrfsic_bh_end_io(struct buffer_head *bh, int uptodate)
2156 {
2157         struct btrfsic_block *block = (struct btrfsic_block *)bh->b_private;
2158         int iodone_w_error = !uptodate;
2159         struct btrfsic_dev_state *dev_state;
2160
2161         BUG_ON(NULL == block);
2162         dev_state = block->dev_state;
2163         if ((dev_state->state->print_mask & BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2164                 pr_info("bh_end_io(error=%d) for %c @%llu (%s/%llu/%d)\n",
2165                        iodone_w_error,
2166                        btrfsic_get_block_type(dev_state->state, block),
2167                        block->logical_bytenr, block->dev_state->name,
2168                        block->dev_bytenr, block->mirror_num);
2169
2170         block->iodone_w_error = iodone_w_error;
2171         if (block->submit_bio_bh_rw & REQ_PREFLUSH) {
2172                 dev_state->last_flush_gen++;
2173                 if ((dev_state->state->print_mask &
2174                      BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2175                         pr_info("bh_end_io() new %s flush_gen=%llu\n",
2176                                dev_state->name, dev_state->last_flush_gen);
2177         }
2178         if (block->submit_bio_bh_rw & REQ_FUA)
2179                 block->flush_gen = 0; /* FUA completed means block is on disk */
2180
2181         bh->b_private = block->orig_bio_bh_private;
2182         bh->b_end_io = block->orig_bio_bh_end_io.bh;
2183         block->is_iodone = 1; /* for FLUSH, this releases the block */
2184         bh->b_end_io(bh, uptodate);
2185 }
2186
2187 static int btrfsic_process_written_superblock(
2188                 struct btrfsic_state *state,
2189                 struct btrfsic_block *const superblock,
2190                 struct btrfs_super_block *const super_hdr)
2191 {
2192         struct btrfs_fs_info *fs_info = state->fs_info;
2193         int pass;
2194
2195         superblock->generation = btrfs_super_generation(super_hdr);
2196         if (!(superblock->generation > state->max_superblock_generation ||
2197               0 == state->max_superblock_generation)) {
2198                 if (state->print_mask & BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE)
2199                         pr_info("btrfsic: superblock @%llu (%s/%llu/%d) with old gen %llu <= %llu\n",
2200                                superblock->logical_bytenr,
2201                                superblock->dev_state->name,
2202                                superblock->dev_bytenr, superblock->mirror_num,
2203                                btrfs_super_generation(super_hdr),
2204                                state->max_superblock_generation);
2205         } else {
2206                 if (state->print_mask & BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE)
2207                         pr_info("btrfsic: got new superblock @%llu (%s/%llu/%d) with new gen %llu > %llu\n",
2208                                superblock->logical_bytenr,
2209                                superblock->dev_state->name,
2210                                superblock->dev_bytenr, superblock->mirror_num,
2211                                btrfs_super_generation(super_hdr),
2212                                state->max_superblock_generation);
2213
2214                 state->max_superblock_generation =
2215                     btrfs_super_generation(super_hdr);
2216                 state->latest_superblock = superblock;
2217         }
2218
2219         for (pass = 0; pass < 3; pass++) {
2220                 int ret;
2221                 u64 next_bytenr;
2222                 struct btrfsic_block *next_block;
2223                 struct btrfsic_block_data_ctx tmp_next_block_ctx;
2224                 struct btrfsic_block_link *l;
2225                 int num_copies;
2226                 int mirror_num;
2227                 const char *additional_string = NULL;
2228                 struct btrfs_disk_key tmp_disk_key = {0};
2229
2230                 btrfs_set_disk_key_objectid(&tmp_disk_key,
2231                                             BTRFS_ROOT_ITEM_KEY);
2232                 btrfs_set_disk_key_objectid(&tmp_disk_key, 0);
2233
2234                 switch (pass) {
2235                 case 0:
2236                         btrfs_set_disk_key_objectid(&tmp_disk_key,
2237                                                     BTRFS_ROOT_TREE_OBJECTID);
2238                         additional_string = "root ";
2239                         next_bytenr = btrfs_super_root(super_hdr);
2240                         if (state->print_mask &
2241                             BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
2242                                 pr_info("root@%llu\n", next_bytenr);
2243                         break;
2244                 case 1:
2245                         btrfs_set_disk_key_objectid(&tmp_disk_key,
2246                                                     BTRFS_CHUNK_TREE_OBJECTID);
2247                         additional_string = "chunk ";
2248                         next_bytenr = btrfs_super_chunk_root(super_hdr);
2249                         if (state->print_mask &
2250                             BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
2251                                 pr_info("chunk@%llu\n", next_bytenr);
2252                         break;
2253                 case 2:
2254                         btrfs_set_disk_key_objectid(&tmp_disk_key,
2255                                                     BTRFS_TREE_LOG_OBJECTID);
2256                         additional_string = "log ";
2257                         next_bytenr = btrfs_super_log_root(super_hdr);
2258                         if (0 == next_bytenr)
2259                                 continue;
2260                         if (state->print_mask &
2261                             BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
2262                                 pr_info("log@%llu\n", next_bytenr);
2263                         break;
2264                 }
2265
2266                 num_copies = btrfs_num_copies(fs_info, next_bytenr,
2267                                               BTRFS_SUPER_INFO_SIZE);
2268                 if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
2269                         pr_info("num_copies(log_bytenr=%llu) = %d\n",
2270                                next_bytenr, num_copies);
2271                 for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
2272                         int was_created;
2273
2274                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2275                                 pr_info("btrfsic_process_written_superblock(mirror_num=%d)\n", mirror_num);
2276                         ret = btrfsic_map_block(state, next_bytenr,
2277                                                 BTRFS_SUPER_INFO_SIZE,
2278                                                 &tmp_next_block_ctx,
2279                                                 mirror_num);
2280                         if (ret) {
2281                                 pr_info("btrfsic: btrfsic_map_block(@%llu, mirror=%d) failed!\n",
2282                                        next_bytenr, mirror_num);
2283                                 return -1;
2284                         }
2285
2286                         next_block = btrfsic_block_lookup_or_add(
2287                                         state,
2288                                         &tmp_next_block_ctx,
2289                                         additional_string,
2290                                         1, 0, 1,
2291                                         mirror_num,
2292                                         &was_created);
2293                         if (NULL == next_block) {
2294                                 pr_info("btrfsic: error, kmalloc failed!\n");
2295                                 btrfsic_release_block_ctx(&tmp_next_block_ctx);
2296                                 return -1;
2297                         }
2298
2299                         next_block->disk_key = tmp_disk_key;
2300                         if (was_created)
2301                                 next_block->generation =
2302                                     BTRFSIC_GENERATION_UNKNOWN;
2303                         l = btrfsic_block_link_lookup_or_add(
2304                                         state,
2305                                         &tmp_next_block_ctx,
2306                                         next_block,
2307                                         superblock,
2308                                         BTRFSIC_GENERATION_UNKNOWN);
2309                         btrfsic_release_block_ctx(&tmp_next_block_ctx);
2310                         if (NULL == l)
2311                                 return -1;
2312                 }
2313         }
2314
2315         if (WARN_ON(-1 == btrfsic_check_all_ref_blocks(state, superblock, 0)))
2316                 btrfsic_dump_tree(state);
2317
2318         return 0;
2319 }
2320
2321 static int btrfsic_check_all_ref_blocks(struct btrfsic_state *state,
2322                                         struct btrfsic_block *const block,
2323                                         int recursion_level)
2324 {
2325         const struct btrfsic_block_link *l;
2326         int ret = 0;
2327
2328         if (recursion_level >= 3 + BTRFS_MAX_LEVEL) {
2329                 /*
2330                  * Note that this situation can happen and does not
2331                  * indicate an error in regular cases. It happens
2332                  * when disk blocks are freed and later reused.
2333                  * The check-integrity module is not aware of any
2334                  * block free operations, it just recognizes block
2335                  * write operations. Therefore it keeps the linkage
2336                  * information for a block until a block is
2337                  * rewritten. This can temporarily cause incorrect
2338                  * and even circular linkage informations. This
2339                  * causes no harm unless such blocks are referenced
2340                  * by the most recent super block.
2341                  */
2342                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2343                         pr_info("btrfsic: abort cyclic linkage (case 1).\n");
2344
2345                 return ret;
2346         }
2347
2348         /*
2349          * This algorithm is recursive because the amount of used stack
2350          * space is very small and the max recursion depth is limited.
2351          */
2352         list_for_each_entry(l, &block->ref_to_list, node_ref_to) {
2353                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2354                         pr_info("rl=%d, %c @%llu (%s/%llu/%d) %u* refers to %c @%llu (%s/%llu/%d)\n",
2355                                recursion_level,
2356                                btrfsic_get_block_type(state, block),
2357                                block->logical_bytenr, block->dev_state->name,
2358                                block->dev_bytenr, block->mirror_num,
2359                                l->ref_cnt,
2360                                btrfsic_get_block_type(state, l->block_ref_to),
2361                                l->block_ref_to->logical_bytenr,
2362                                l->block_ref_to->dev_state->name,
2363                                l->block_ref_to->dev_bytenr,
2364                                l->block_ref_to->mirror_num);
2365                 if (l->block_ref_to->never_written) {
2366                         pr_info("btrfs: attempt to write superblock which references block %c @%llu (%s/%llu/%d) which is never written!\n",
2367                                btrfsic_get_block_type(state, l->block_ref_to),
2368                                l->block_ref_to->logical_bytenr,
2369                                l->block_ref_to->dev_state->name,
2370                                l->block_ref_to->dev_bytenr,
2371                                l->block_ref_to->mirror_num);
2372                         ret = -1;
2373                 } else if (!l->block_ref_to->is_iodone) {
2374                         pr_info("btrfs: attempt to write superblock which references block %c @%llu (%s/%llu/%d) which is not yet iodone!\n",
2375                                btrfsic_get_block_type(state, l->block_ref_to),
2376                                l->block_ref_to->logical_bytenr,
2377                                l->block_ref_to->dev_state->name,
2378                                l->block_ref_to->dev_bytenr,
2379                                l->block_ref_to->mirror_num);
2380                         ret = -1;
2381                 } else if (l->block_ref_to->iodone_w_error) {
2382                         pr_info("btrfs: attempt to write superblock which references block %c @%llu (%s/%llu/%d) which has write error!\n",
2383                                btrfsic_get_block_type(state, l->block_ref_to),
2384                                l->block_ref_to->logical_bytenr,
2385                                l->block_ref_to->dev_state->name,
2386                                l->block_ref_to->dev_bytenr,
2387                                l->block_ref_to->mirror_num);
2388                         ret = -1;
2389                 } else if (l->parent_generation !=
2390                            l->block_ref_to->generation &&
2391                            BTRFSIC_GENERATION_UNKNOWN !=
2392                            l->parent_generation &&
2393                            BTRFSIC_GENERATION_UNKNOWN !=
2394                            l->block_ref_to->generation) {
2395                         pr_info("btrfs: attempt to write superblock which references block %c @%llu (%s/%llu/%d) with generation %llu != parent generation %llu!\n",
2396                                btrfsic_get_block_type(state, l->block_ref_to),
2397                                l->block_ref_to->logical_bytenr,
2398                                l->block_ref_to->dev_state->name,
2399                                l->block_ref_to->dev_bytenr,
2400                                l->block_ref_to->mirror_num,
2401                                l->block_ref_to->generation,
2402                                l->parent_generation);
2403                         ret = -1;
2404                 } else if (l->block_ref_to->flush_gen >
2405                            l->block_ref_to->dev_state->last_flush_gen) {
2406                         pr_info("btrfs: attempt to write superblock which references block %c @%llu (%s/%llu/%d) which is not flushed out of disk's write cache (block flush_gen=%llu, dev->flush_gen=%llu)!\n",
2407                                btrfsic_get_block_type(state, l->block_ref_to),
2408                                l->block_ref_to->logical_bytenr,
2409                                l->block_ref_to->dev_state->name,
2410                                l->block_ref_to->dev_bytenr,
2411                                l->block_ref_to->mirror_num, block->flush_gen,
2412                                l->block_ref_to->dev_state->last_flush_gen);
2413                         ret = -1;
2414                 } else if (-1 == btrfsic_check_all_ref_blocks(state,
2415                                                               l->block_ref_to,
2416                                                               recursion_level +
2417                                                               1)) {
2418                         ret = -1;
2419                 }
2420         }
2421
2422         return ret;
2423 }
2424
2425 static int btrfsic_is_block_ref_by_superblock(
2426                 const struct btrfsic_state *state,
2427                 const struct btrfsic_block *block,
2428                 int recursion_level)
2429 {
2430         const struct btrfsic_block_link *l;
2431
2432         if (recursion_level >= 3 + BTRFS_MAX_LEVEL) {
2433                 /* refer to comment at "abort cyclic linkage (case 1)" */
2434                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2435                         pr_info("btrfsic: abort cyclic linkage (case 2).\n");
2436
2437                 return 0;
2438         }
2439
2440         /*
2441          * This algorithm is recursive because the amount of used stack space
2442          * is very small and the max recursion depth is limited.
2443          */
2444         list_for_each_entry(l, &block->ref_from_list, node_ref_from) {
2445                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2446                         pr_info("rl=%d, %c @%llu (%s/%llu/%d) is ref %u* from %c @%llu (%s/%llu/%d)\n",
2447                                recursion_level,
2448                                btrfsic_get_block_type(state, block),
2449                                block->logical_bytenr, block->dev_state->name,
2450                                block->dev_bytenr, block->mirror_num,
2451                                l->ref_cnt,
2452                                btrfsic_get_block_type(state, l->block_ref_from),
2453                                l->block_ref_from->logical_bytenr,
2454                                l->block_ref_from->dev_state->name,
2455                                l->block_ref_from->dev_bytenr,
2456                                l->block_ref_from->mirror_num);
2457                 if (l->block_ref_from->is_superblock &&
2458                     state->latest_superblock->dev_bytenr ==
2459                     l->block_ref_from->dev_bytenr &&
2460                     state->latest_superblock->dev_state->bdev ==
2461                     l->block_ref_from->dev_state->bdev)
2462                         return 1;
2463                 else if (btrfsic_is_block_ref_by_superblock(state,
2464                                                             l->block_ref_from,
2465                                                             recursion_level +
2466                                                             1))
2467                         return 1;
2468         }
2469
2470         return 0;
2471 }
2472
2473 static void btrfsic_print_add_link(const struct btrfsic_state *state,
2474                                    const struct btrfsic_block_link *l)
2475 {
2476         pr_info("Add %u* link from %c @%llu (%s/%llu/%d) to %c @%llu (%s/%llu/%d).\n",
2477                l->ref_cnt,
2478                btrfsic_get_block_type(state, l->block_ref_from),
2479                l->block_ref_from->logical_bytenr,
2480                l->block_ref_from->dev_state->name,
2481                l->block_ref_from->dev_bytenr, l->block_ref_from->mirror_num,
2482                btrfsic_get_block_type(state, l->block_ref_to),
2483                l->block_ref_to->logical_bytenr,
2484                l->block_ref_to->dev_state->name, l->block_ref_to->dev_bytenr,
2485                l->block_ref_to->mirror_num);
2486 }
2487
2488 static void btrfsic_print_rem_link(const struct btrfsic_state *state,
2489                                    const struct btrfsic_block_link *l)
2490 {
2491         pr_info("Rem %u* link from %c @%llu (%s/%llu/%d) to %c @%llu (%s/%llu/%d).\n",
2492                l->ref_cnt,
2493                btrfsic_get_block_type(state, l->block_ref_from),
2494                l->block_ref_from->logical_bytenr,
2495                l->block_ref_from->dev_state->name,
2496                l->block_ref_from->dev_bytenr, l->block_ref_from->mirror_num,
2497                btrfsic_get_block_type(state, l->block_ref_to),
2498                l->block_ref_to->logical_bytenr,
2499                l->block_ref_to->dev_state->name, l->block_ref_to->dev_bytenr,
2500                l->block_ref_to->mirror_num);
2501 }
2502
2503 static char btrfsic_get_block_type(const struct btrfsic_state *state,
2504                                    const struct btrfsic_block *block)
2505 {
2506         if (block->is_superblock &&
2507             state->latest_superblock->dev_bytenr == block->dev_bytenr &&
2508             state->latest_superblock->dev_state->bdev == block->dev_state->bdev)
2509                 return 'S';
2510         else if (block->is_superblock)
2511                 return 's';
2512         else if (block->is_metadata)
2513                 return 'M';
2514         else
2515                 return 'D';
2516 }
2517
2518 static void btrfsic_dump_tree(const struct btrfsic_state *state)
2519 {
2520         btrfsic_dump_tree_sub(state, state->latest_superblock, 0);
2521 }
2522
2523 static void btrfsic_dump_tree_sub(const struct btrfsic_state *state,
2524                                   const struct btrfsic_block *block,
2525                                   int indent_level)
2526 {
2527         const struct btrfsic_block_link *l;
2528         int indent_add;
2529         static char buf[80];
2530         int cursor_position;
2531
2532         /*
2533          * Should better fill an on-stack buffer with a complete line and
2534          * dump it at once when it is time to print a newline character.
2535          */
2536
2537         /*
2538          * This algorithm is recursive because the amount of used stack space
2539          * is very small and the max recursion depth is limited.
2540          */
2541         indent_add = sprintf(buf, "%c-%llu(%s/%llu/%u)",
2542                              btrfsic_get_block_type(state, block),
2543                              block->logical_bytenr, block->dev_state->name,
2544                              block->dev_bytenr, block->mirror_num);
2545         if (indent_level + indent_add > BTRFSIC_TREE_DUMP_MAX_INDENT_LEVEL) {
2546                 printk("[...]\n");
2547                 return;
2548         }
2549         printk(buf);
2550         indent_level += indent_add;
2551         if (list_empty(&block->ref_to_list)) {
2552                 printk("\n");
2553                 return;
2554         }
2555         if (block->mirror_num > 1 &&
2556             !(state->print_mask & BTRFSIC_PRINT_MASK_TREE_WITH_ALL_MIRRORS)) {
2557                 printk(" [...]\n");
2558                 return;
2559         }
2560
2561         cursor_position = indent_level;
2562         list_for_each_entry(l, &block->ref_to_list, node_ref_to) {
2563                 while (cursor_position < indent_level) {
2564                         printk(" ");
2565                         cursor_position++;
2566                 }
2567                 if (l->ref_cnt > 1)
2568                         indent_add = sprintf(buf, " %d*--> ", l->ref_cnt);
2569                 else
2570                         indent_add = sprintf(buf, " --> ");
2571                 if (indent_level + indent_add >
2572                     BTRFSIC_TREE_DUMP_MAX_INDENT_LEVEL) {
2573                         printk("[...]\n");
2574                         cursor_position = 0;
2575                         continue;
2576                 }
2577
2578                 printk(buf);
2579
2580                 btrfsic_dump_tree_sub(state, l->block_ref_to,
2581                                       indent_level + indent_add);
2582                 cursor_position = 0;
2583         }
2584 }
2585
2586 static struct btrfsic_block_link *btrfsic_block_link_lookup_or_add(
2587                 struct btrfsic_state *state,
2588                 struct btrfsic_block_data_ctx *next_block_ctx,
2589                 struct btrfsic_block *next_block,
2590                 struct btrfsic_block *from_block,
2591                 u64 parent_generation)
2592 {
2593         struct btrfsic_block_link *l;
2594
2595         l = btrfsic_block_link_hashtable_lookup(next_block_ctx->dev->bdev,
2596                                                 next_block_ctx->dev_bytenr,
2597                                                 from_block->dev_state->bdev,
2598                                                 from_block->dev_bytenr,
2599                                                 &state->block_link_hashtable);
2600         if (NULL == l) {
2601                 l = btrfsic_block_link_alloc();
2602                 if (NULL == l) {
2603                         pr_info("btrfsic: error, kmalloc failed!\n");
2604                         return NULL;
2605                 }
2606
2607                 l->block_ref_to = next_block;
2608                 l->block_ref_from = from_block;
2609                 l->ref_cnt = 1;
2610                 l->parent_generation = parent_generation;
2611
2612                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2613                         btrfsic_print_add_link(state, l);
2614
2615                 list_add(&l->node_ref_to, &from_block->ref_to_list);
2616                 list_add(&l->node_ref_from, &next_block->ref_from_list);
2617
2618                 btrfsic_block_link_hashtable_add(l,
2619                                                  &state->block_link_hashtable);
2620         } else {
2621                 l->ref_cnt++;
2622                 l->parent_generation = parent_generation;
2623                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2624                         btrfsic_print_add_link(state, l);
2625         }
2626
2627         return l;
2628 }
2629
2630 static struct btrfsic_block *btrfsic_block_lookup_or_add(
2631                 struct btrfsic_state *state,
2632                 struct btrfsic_block_data_ctx *block_ctx,
2633                 const char *additional_string,
2634                 int is_metadata,
2635                 int is_iodone,
2636                 int never_written,
2637                 int mirror_num,
2638                 int *was_created)
2639 {
2640         struct btrfsic_block *block;
2641
2642         block = btrfsic_block_hashtable_lookup(block_ctx->dev->bdev,
2643                                                block_ctx->dev_bytenr,
2644                                                &state->block_hashtable);
2645         if (NULL == block) {
2646                 struct btrfsic_dev_state *dev_state;
2647
2648                 block = btrfsic_block_alloc();
2649                 if (NULL == block) {
2650                         pr_info("btrfsic: error, kmalloc failed!\n");
2651                         return NULL;
2652                 }
2653                 dev_state = btrfsic_dev_state_lookup(block_ctx->dev->bdev->bd_dev);
2654                 if (NULL == dev_state) {
2655                         pr_info("btrfsic: error, lookup dev_state failed!\n");
2656                         btrfsic_block_free(block);
2657                         return NULL;
2658                 }
2659                 block->dev_state = dev_state;
2660                 block->dev_bytenr = block_ctx->dev_bytenr;
2661                 block->logical_bytenr = block_ctx->start;
2662                 block->is_metadata = is_metadata;
2663                 block->is_iodone = is_iodone;
2664                 block->never_written = never_written;
2665                 block->mirror_num = mirror_num;
2666                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2667                         pr_info("New %s%c-block @%llu (%s/%llu/%d)\n",
2668                                additional_string,
2669                                btrfsic_get_block_type(state, block),
2670                                block->logical_bytenr, dev_state->name,
2671                                block->dev_bytenr, mirror_num);
2672                 list_add(&block->all_blocks_node, &state->all_blocks_list);
2673                 btrfsic_block_hashtable_add(block, &state->block_hashtable);
2674                 if (NULL != was_created)
2675                         *was_created = 1;
2676         } else {
2677                 if (NULL != was_created)
2678                         *was_created = 0;
2679         }
2680
2681         return block;
2682 }
2683
2684 static void btrfsic_cmp_log_and_dev_bytenr(struct btrfsic_state *state,
2685                                            u64 bytenr,
2686                                            struct btrfsic_dev_state *dev_state,
2687                                            u64 dev_bytenr)
2688 {
2689         struct btrfs_fs_info *fs_info = state->fs_info;
2690         struct btrfsic_block_data_ctx block_ctx;
2691         int num_copies;
2692         int mirror_num;
2693         int match = 0;
2694         int ret;
2695
2696         num_copies = btrfs_num_copies(fs_info, bytenr, state->metablock_size);
2697
2698         for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
2699                 ret = btrfsic_map_block(state, bytenr, state->metablock_size,
2700                                         &block_ctx, mirror_num);
2701                 if (ret) {
2702                         pr_info("btrfsic: btrfsic_map_block(logical @%llu, mirror %d) failed!\n",
2703                                bytenr, mirror_num);
2704                         continue;
2705                 }
2706
2707                 if (dev_state->bdev == block_ctx.dev->bdev &&
2708                     dev_bytenr == block_ctx.dev_bytenr) {
2709                         match++;
2710                         btrfsic_release_block_ctx(&block_ctx);
2711                         break;
2712                 }
2713                 btrfsic_release_block_ctx(&block_ctx);
2714         }
2715
2716         if (WARN_ON(!match)) {
2717                 pr_info("btrfs: attempt to write M-block which contains logical bytenr that doesn't map to dev+physical bytenr of submit_bio, buffer->log_bytenr=%llu, submit_bio(bdev=%s, phys_bytenr=%llu)!\n",
2718                        bytenr, dev_state->name, dev_bytenr);
2719                 for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
2720                         ret = btrfsic_map_block(state, bytenr,
2721                                                 state->metablock_size,
2722                                                 &block_ctx, mirror_num);
2723                         if (ret)
2724                                 continue;
2725
2726                         pr_info("Read logical bytenr @%llu maps to (%s/%llu/%d)\n",
2727                                bytenr, block_ctx.dev->name,
2728                                block_ctx.dev_bytenr, mirror_num);
2729                 }
2730         }
2731 }
2732
2733 static struct btrfsic_dev_state *btrfsic_dev_state_lookup(dev_t dev)
2734 {
2735         return btrfsic_dev_state_hashtable_lookup(dev,
2736                                                   &btrfsic_dev_state_hashtable);
2737 }
2738
2739 int btrfsic_submit_bh(int op, int op_flags, struct buffer_head *bh)
2740 {
2741         struct btrfsic_dev_state *dev_state;
2742
2743         if (!btrfsic_is_initialized)
2744                 return submit_bh(op, op_flags, bh);
2745
2746         mutex_lock(&btrfsic_mutex);
2747         /* since btrfsic_submit_bh() might also be called before
2748          * btrfsic_mount(), this might return NULL */
2749         dev_state = btrfsic_dev_state_lookup(bh->b_bdev->bd_dev);
2750
2751         /* Only called to write the superblock (incl. FLUSH/FUA) */
2752         if (NULL != dev_state &&
2753             (op == REQ_OP_WRITE) && bh->b_size > 0) {
2754                 u64 dev_bytenr;
2755
2756                 dev_bytenr = BTRFS_BDEV_BLOCKSIZE * bh->b_blocknr;
2757                 if (dev_state->state->print_mask &
2758                     BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
2759                         pr_info("submit_bh(op=0x%x,0x%x, blocknr=%llu (bytenr %llu), size=%zu, data=%p, bdev=%p)\n",
2760                                op, op_flags, (unsigned long long)bh->b_blocknr,
2761                                dev_bytenr, bh->b_size, bh->b_data, bh->b_bdev);
2762                 btrfsic_process_written_block(dev_state, dev_bytenr,
2763                                               &bh->b_data, 1, NULL,
2764                                               NULL, bh, op_flags);
2765         } else if (NULL != dev_state && (op_flags & REQ_PREFLUSH)) {
2766                 if (dev_state->state->print_mask &
2767                     BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
2768                         pr_info("submit_bh(op=0x%x,0x%x FLUSH, bdev=%p)\n",
2769                                op, op_flags, bh->b_bdev);
2770                 if (!dev_state->dummy_block_for_bio_bh_flush.is_iodone) {
2771                         if ((dev_state->state->print_mask &
2772                              (BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH |
2773                               BTRFSIC_PRINT_MASK_VERBOSE)))
2774                                 pr_info("btrfsic_submit_bh(%s) with FLUSH but dummy block already in use (ignored)!\n",
2775                                        dev_state->name);
2776                 } else {
2777                         struct btrfsic_block *const block =
2778                                 &dev_state->dummy_block_for_bio_bh_flush;
2779
2780                         block->is_iodone = 0;
2781                         block->never_written = 0;
2782                         block->iodone_w_error = 0;
2783                         block->flush_gen = dev_state->last_flush_gen + 1;
2784                         block->submit_bio_bh_rw = op_flags;
2785                         block->orig_bio_bh_private = bh->b_private;
2786                         block->orig_bio_bh_end_io.bh = bh->b_end_io;
2787                         block->next_in_same_bio = NULL;
2788                         bh->b_private = block;
2789                         bh->b_end_io = btrfsic_bh_end_io;
2790                 }
2791         }
2792         mutex_unlock(&btrfsic_mutex);
2793         return submit_bh(op, op_flags, bh);
2794 }
2795
2796 static void __btrfsic_submit_bio(struct bio *bio)
2797 {
2798         struct btrfsic_dev_state *dev_state;
2799
2800         if (!btrfsic_is_initialized)
2801                 return;
2802
2803         mutex_lock(&btrfsic_mutex);
2804         /* since btrfsic_submit_bio() is also called before
2805          * btrfsic_mount(), this might return NULL */
2806         dev_state = btrfsic_dev_state_lookup(bio_dev(bio) + bio->bi_partno);
2807         if (NULL != dev_state &&
2808             (bio_op(bio) == REQ_OP_WRITE) && bio_has_data(bio)) {
2809                 unsigned int i = 0;
2810                 u64 dev_bytenr;
2811                 u64 cur_bytenr;
2812                 struct bio_vec bvec;
2813                 struct bvec_iter iter;
2814                 int bio_is_patched;
2815                 char **mapped_datav;
2816                 unsigned int segs = bio_segments(bio);
2817
2818                 dev_bytenr = 512 * bio->bi_iter.bi_sector;
2819                 bio_is_patched = 0;
2820                 if (dev_state->state->print_mask &
2821                     BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
2822                         pr_info("submit_bio(rw=%d,0x%x, bi_vcnt=%u, bi_sector=%llu (bytenr %llu), bi_disk=%p)\n",
2823                                bio_op(bio), bio->bi_opf, segs,
2824                                (unsigned long long)bio->bi_iter.bi_sector,
2825                                dev_bytenr, bio->bi_disk);
2826
2827                 mapped_datav = kmalloc_array(segs,
2828                                              sizeof(*mapped_datav), GFP_NOFS);
2829                 if (!mapped_datav)
2830                         goto leave;
2831                 cur_bytenr = dev_bytenr;
2832
2833                 bio_for_each_segment(bvec, bio, iter) {
2834                         BUG_ON(bvec.bv_len != PAGE_SIZE);
2835                         mapped_datav[i] = kmap(bvec.bv_page);
2836                         i++;
2837
2838                         if (dev_state->state->print_mask &
2839                             BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH_VERBOSE)
2840                                 pr_info("#%u: bytenr=%llu, len=%u, offset=%u\n",
2841                                        i, cur_bytenr, bvec.bv_len, bvec.bv_offset);
2842                         cur_bytenr += bvec.bv_len;
2843                 }
2844                 btrfsic_process_written_block(dev_state, dev_bytenr,
2845                                               mapped_datav, segs,
2846                                               bio, &bio_is_patched,
2847                                               NULL, bio->bi_opf);
2848                 bio_for_each_segment(bvec, bio, iter)
2849                         kunmap(bvec.bv_page);
2850                 kfree(mapped_datav);
2851         } else if (NULL != dev_state && (bio->bi_opf & REQ_PREFLUSH)) {
2852                 if (dev_state->state->print_mask &
2853                     BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
2854                         pr_info("submit_bio(rw=%d,0x%x FLUSH, disk=%p)\n",
2855                                bio_op(bio), bio->bi_opf, bio->bi_disk);
2856                 if (!dev_state->dummy_block_for_bio_bh_flush.is_iodone) {
2857                         if ((dev_state->state->print_mask &
2858                              (BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH |
2859                               BTRFSIC_PRINT_MASK_VERBOSE)))
2860                                 pr_info("btrfsic_submit_bio(%s) with FLUSH but dummy block already in use (ignored)!\n",
2861                                        dev_state->name);
2862                 } else {
2863                         struct btrfsic_block *const block =
2864                                 &dev_state->dummy_block_for_bio_bh_flush;
2865
2866                         block->is_iodone = 0;
2867                         block->never_written = 0;
2868                         block->iodone_w_error = 0;
2869                         block->flush_gen = dev_state->last_flush_gen + 1;
2870                         block->submit_bio_bh_rw = bio->bi_opf;
2871                         block->orig_bio_bh_private = bio->bi_private;
2872                         block->orig_bio_bh_end_io.bio = bio->bi_end_io;
2873                         block->next_in_same_bio = NULL;
2874                         bio->bi_private = block;
2875                         bio->bi_end_io = btrfsic_bio_end_io;
2876                 }
2877         }
2878 leave:
2879         mutex_unlock(&btrfsic_mutex);
2880 }
2881
2882 void btrfsic_submit_bio(struct bio *bio)
2883 {
2884         __btrfsic_submit_bio(bio);
2885         submit_bio(bio);
2886 }
2887
2888 int btrfsic_submit_bio_wait(struct bio *bio)
2889 {
2890         __btrfsic_submit_bio(bio);
2891         return submit_bio_wait(bio);
2892 }
2893
2894 int btrfsic_mount(struct btrfs_fs_info *fs_info,
2895                   struct btrfs_fs_devices *fs_devices,
2896                   int including_extent_data, u32 print_mask)
2897 {
2898         int ret;
2899         struct btrfsic_state *state;
2900         struct list_head *dev_head = &fs_devices->devices;
2901         struct btrfs_device *device;
2902
2903         if (fs_info->nodesize & ((u64)PAGE_SIZE - 1)) {
2904                 pr_info("btrfsic: cannot handle nodesize %d not being a multiple of PAGE_SIZE %ld!\n",
2905                        fs_info->nodesize, PAGE_SIZE);
2906                 return -1;
2907         }
2908         if (fs_info->sectorsize & ((u64)PAGE_SIZE - 1)) {
2909                 pr_info("btrfsic: cannot handle sectorsize %d not being a multiple of PAGE_SIZE %ld!\n",
2910                        fs_info->sectorsize, PAGE_SIZE);
2911                 return -1;
2912         }
2913         state = kvzalloc(sizeof(*state), GFP_KERNEL);
2914         if (!state) {
2915                 pr_info("btrfs check-integrity: allocation failed!\n");
2916                 return -ENOMEM;
2917         }
2918
2919         if (!btrfsic_is_initialized) {
2920                 mutex_init(&btrfsic_mutex);
2921                 btrfsic_dev_state_hashtable_init(&btrfsic_dev_state_hashtable);
2922                 btrfsic_is_initialized = 1;
2923         }
2924         mutex_lock(&btrfsic_mutex);
2925         state->fs_info = fs_info;
2926         state->print_mask = print_mask;
2927         state->include_extent_data = including_extent_data;
2928         state->csum_size = 0;
2929         state->metablock_size = fs_info->nodesize;
2930         state->datablock_size = fs_info->sectorsize;
2931         INIT_LIST_HEAD(&state->all_blocks_list);
2932         btrfsic_block_hashtable_init(&state->block_hashtable);
2933         btrfsic_block_link_hashtable_init(&state->block_link_hashtable);
2934         state->max_superblock_generation = 0;
2935         state->latest_superblock = NULL;
2936
2937         list_for_each_entry(device, dev_head, dev_list) {
2938                 struct btrfsic_dev_state *ds;
2939                 const char *p;
2940
2941                 if (!device->bdev || !device->name)
2942                         continue;
2943
2944                 ds = btrfsic_dev_state_alloc();
2945                 if (NULL == ds) {
2946                         pr_info("btrfs check-integrity: kmalloc() failed!\n");
2947                         mutex_unlock(&btrfsic_mutex);
2948                         return -ENOMEM;
2949                 }
2950                 ds->bdev = device->bdev;
2951                 ds->state = state;
2952                 bdevname(ds->bdev, ds->name);
2953                 ds->name[BDEVNAME_SIZE - 1] = '\0';
2954                 p = kbasename(ds->name);
2955                 strlcpy(ds->name, p, sizeof(ds->name));
2956                 btrfsic_dev_state_hashtable_add(ds,
2957                                                 &btrfsic_dev_state_hashtable);
2958         }
2959
2960         ret = btrfsic_process_superblock(state, fs_devices);
2961         if (0 != ret) {
2962                 mutex_unlock(&btrfsic_mutex);
2963                 btrfsic_unmount(fs_devices);
2964                 return ret;
2965         }
2966
2967         if (state->print_mask & BTRFSIC_PRINT_MASK_INITIAL_DATABASE)
2968                 btrfsic_dump_database(state);
2969         if (state->print_mask & BTRFSIC_PRINT_MASK_INITIAL_TREE)
2970                 btrfsic_dump_tree(state);
2971
2972         mutex_unlock(&btrfsic_mutex);
2973         return 0;
2974 }
2975
2976 void btrfsic_unmount(struct btrfs_fs_devices *fs_devices)
2977 {
2978         struct btrfsic_block *b_all, *tmp_all;
2979         struct btrfsic_state *state;
2980         struct list_head *dev_head = &fs_devices->devices;
2981         struct btrfs_device *device;
2982
2983         if (!btrfsic_is_initialized)
2984                 return;
2985
2986         mutex_lock(&btrfsic_mutex);
2987
2988         state = NULL;
2989         list_for_each_entry(device, dev_head, dev_list) {
2990                 struct btrfsic_dev_state *ds;
2991
2992                 if (!device->bdev || !device->name)
2993                         continue;
2994
2995                 ds = btrfsic_dev_state_hashtable_lookup(
2996                                 device->bdev->bd_dev,
2997                                 &btrfsic_dev_state_hashtable);
2998                 if (NULL != ds) {
2999                         state = ds->state;
3000                         btrfsic_dev_state_hashtable_remove(ds);
3001                         btrfsic_dev_state_free(ds);
3002                 }
3003         }
3004
3005         if (NULL == state) {
3006                 pr_info("btrfsic: error, cannot find state information on umount!\n");
3007                 mutex_unlock(&btrfsic_mutex);
3008                 return;
3009         }
3010
3011         /*
3012          * Don't care about keeping the lists' state up to date,
3013          * just free all memory that was allocated dynamically.
3014          * Free the blocks and the block_links.
3015          */
3016         list_for_each_entry_safe(b_all, tmp_all, &state->all_blocks_list,
3017                                  all_blocks_node) {
3018                 struct btrfsic_block_link *l, *tmp;
3019
3020                 list_for_each_entry_safe(l, tmp, &b_all->ref_to_list,
3021                                          node_ref_to) {
3022                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
3023                                 btrfsic_print_rem_link(state, l);
3024
3025                         l->ref_cnt--;
3026                         if (0 == l->ref_cnt)
3027                                 btrfsic_block_link_free(l);
3028                 }
3029
3030                 if (b_all->is_iodone || b_all->never_written)
3031                         btrfsic_block_free(b_all);
3032                 else
3033                         pr_info("btrfs: attempt to free %c-block @%llu (%s/%llu/%d) on umount which is not yet iodone!\n",
3034                                btrfsic_get_block_type(state, b_all),
3035                                b_all->logical_bytenr, b_all->dev_state->name,
3036                                b_all->dev_bytenr, b_all->mirror_num);
3037         }
3038
3039         mutex_unlock(&btrfsic_mutex);
3040
3041         kvfree(state);
3042 }