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 "ctree.h"
 100 #include "disk-io.h"
 101 #include "hash.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(
 300                 struct block_device *bdev,
 301                 struct btrfsic_dev_state_hashtable *h);
 302 static struct btrfsic_stack_frame *btrfsic_stack_frame_alloc(void);
 303 static void btrfsic_stack_frame_free(struct btrfsic_stack_frame *sf);
 304 static int btrfsic_process_superblock(struct btrfsic_state *state,
 305                                       struct btrfs_fs_devices *fs_devices);
 306 static int btrfsic_process_metablock(struct btrfsic_state *state,
 307                                      struct btrfsic_block *block,
 308                                      struct btrfsic_block_data_ctx *block_ctx,
 309                                      int limit_nesting, int force_iodone_flag);
 310 static void btrfsic_read_from_block_data(
 311         struct btrfsic_block_data_ctx *block_ctx,
 312         void *dst, u32 offset, size_t len);
 313 static int btrfsic_create_link_to_next_block(
 314                 struct btrfsic_state *state,
 315                 struct btrfsic_block *block,
 316                 struct btrfsic_block_data_ctx
 317                 *block_ctx, u64 next_bytenr,
 318                 int limit_nesting,
 319                 struct btrfsic_block_data_ctx *next_block_ctx,
 320                 struct btrfsic_block **next_blockp,
 321                 int force_iodone_flag,
 322                 int *num_copiesp, int *mirror_nump,
 323                 struct btrfs_disk_key *disk_key,
 324                 u64 parent_generation);
 325 static int btrfsic_handle_extent_data(struct btrfsic_state *state,
 326                                       struct btrfsic_block *block,
 327                                       struct btrfsic_block_data_ctx *block_ctx,
 328                                       u32 item_offset, int force_iodone_flag);
 329 static int btrfsic_map_block(struct btrfsic_state *state, u64 bytenr, u32 len,
 330                              struct btrfsic_block_data_ctx *block_ctx_out,
 331                              int mirror_num);
 332 static void btrfsic_release_block_ctx(struct btrfsic_block_data_ctx *block_ctx);
 333 static int btrfsic_read_block(struct btrfsic_state *state,
 334                               struct btrfsic_block_data_ctx *block_ctx);
 335 static void btrfsic_dump_database(struct btrfsic_state *state);
 336 static int btrfsic_test_for_metadata(struct btrfsic_state *state,
 337                                      char **datav, unsigned int num_pages);
 338 static void btrfsic_process_written_block(struct btrfsic_dev_state *dev_state,
 339                                           u64 dev_bytenr, char **mapped_datav,
 340                                           unsigned int num_pages,
 341                                           struct bio *bio, int *bio_is_patched,
 342                                           struct buffer_head *bh,
 343                                           int submit_bio_bh_rw);
 344 static int btrfsic_process_written_superblock(
 345                 struct btrfsic_state *state,
 346                 struct btrfsic_block *const block,
 347                 struct btrfs_super_block *const super_hdr);
 348 static void btrfsic_bio_end_io(struct bio *bp);
 349 static void btrfsic_bh_end_io(struct buffer_head *bh, int uptodate);
 350 static int btrfsic_is_block_ref_by_superblock(const struct btrfsic_state *state,
 351                                               const struct btrfsic_block *block,
 352                                               int recursion_level);
 353 static int btrfsic_check_all_ref_blocks(struct btrfsic_state *state,
 354                                         struct btrfsic_block *const block,
 355                                         int recursion_level);
 356 static void btrfsic_print_add_link(const struct btrfsic_state *state,
 357                                    const struct btrfsic_block_link *l);
 358 static void btrfsic_print_rem_link(const struct btrfsic_state *state,
 359                                    const struct btrfsic_block_link *l);
 360 static char btrfsic_get_block_type(const struct btrfsic_state *state,
 361                                    const struct btrfsic_block *block);
 362 static void btrfsic_dump_tree(const struct btrfsic_state *state);
 363 static void btrfsic_dump_tree_sub(const struct btrfsic_state *state,
 364                                   const struct btrfsic_block *block,
 365                                   int indent_level);
 366 static struct btrfsic_block_link *btrfsic_block_link_lookup_or_add(
 367                 struct btrfsic_state *state,
 368                 struct btrfsic_block_data_ctx *next_block_ctx,
 369                 struct btrfsic_block *next_block,
 370                 struct btrfsic_block *from_block,
 371                 u64 parent_generation);
 372 static struct btrfsic_block *btrfsic_block_lookup_or_add(
 373                 struct btrfsic_state *state,
 374                 struct btrfsic_block_data_ctx *block_ctx,
 375                 const char *additional_string,
 376                 int is_metadata,
 377                 int is_iodone,
 378                 int never_written,
 379                 int mirror_num,
 380                 int *was_created);
 381 static int btrfsic_process_superblock_dev_mirror(
 382                 struct btrfsic_state *state,
 383                 struct btrfsic_dev_state *dev_state,
 384                 struct btrfs_device *device,
 385                 int superblock_mirror_num,
 386                 struct btrfsic_dev_state **selected_dev_state,
 387                 struct btrfs_super_block *selected_super);
 388 static struct btrfsic_dev_state *btrfsic_dev_state_lookup(
 389                 struct block_device *bdev);
 390 static void btrfsic_cmp_log_and_dev_bytenr(struct btrfsic_state *state,
 391                                            u64 bytenr,
 392                                            struct btrfsic_dev_state *dev_state,
 393                                            u64 dev_bytenr);
 394
 395 static struct mutex btrfsic_mutex;
 396 static int btrfsic_is_initialized;
 397 static struct btrfsic_dev_state_hashtable btrfsic_dev_state_hashtable;
 398
 399
 400 static void btrfsic_block_init(struct btrfsic_block *b)
 401 {
 402         b->magic_num = BTRFSIC_BLOCK_MAGIC_NUMBER;
 403         b->dev_state = NULL;
 404         b->dev_bytenr = 0;
 405         b->logical_bytenr = 0;
 406         b->generation = BTRFSIC_GENERATION_UNKNOWN;
 407         b->disk_key.objectid = 0;
 408         b->disk_key.type = 0;
 409         b->disk_key.offset = 0;
 410         b->is_metadata = 0;
 411         b->is_superblock = 0;
 412         b->is_iodone = 0;
 413         b->iodone_w_error = 0;
 414         b->never_written = 0;
 415         b->mirror_num = 0;
 416         b->next_in_same_bio = NULL;
 417         b->orig_bio_bh_private = NULL;
 418         b->orig_bio_bh_end_io.bio = NULL;
 419         INIT_LIST_HEAD(&b->collision_resolving_node);
 420         INIT_LIST_HEAD(&b->all_blocks_node);
 421         INIT_LIST_HEAD(&b->ref_to_list);
 422         INIT_LIST_HEAD(&b->ref_from_list);
 423         b->submit_bio_bh_rw = 0;
 424         b->flush_gen = 0;
 425 }
 426
 427 static struct btrfsic_block *btrfsic_block_alloc(void)
 428 {
 429         struct btrfsic_block *b;
 430
 431         b = kzalloc(sizeof(*b), GFP_NOFS);
 432         if (NULL != b)
 433                 btrfsic_block_init(b);
 434
 435         return b;
 436 }
 437
 438 static void btrfsic_block_free(struct btrfsic_block *b)
 439 {
 440         BUG_ON(!(NULL == b || BTRFSIC_BLOCK_MAGIC_NUMBER == b->magic_num));
 441         kfree(b);
 442 }
 443
 444 static void btrfsic_block_link_init(struct btrfsic_block_link *l)
 445 {
 446         l->magic_num = BTRFSIC_BLOCK_LINK_MAGIC_NUMBER;
 447         l->ref_cnt = 1;
 448         INIT_LIST_HEAD(&l->node_ref_to);
 449         INIT_LIST_HEAD(&l->node_ref_from);
 450         INIT_LIST_HEAD(&l->collision_resolving_node);
 451         l->block_ref_to = NULL;
 452         l->block_ref_from = NULL;
 453 }
 454
 455 static struct btrfsic_block_link *btrfsic_block_link_alloc(void)
 456 {
 457         struct btrfsic_block_link *l;
 458
 459         l = kzalloc(sizeof(*l), GFP_NOFS);
 460         if (NULL != l)
 461                 btrfsic_block_link_init(l);
 462
 463         return l;
 464 }
 465
 466 static void btrfsic_block_link_free(struct btrfsic_block_link *l)
 467 {
 468         BUG_ON(!(NULL == l || BTRFSIC_BLOCK_LINK_MAGIC_NUMBER == l->magic_num));
 469         kfree(l);
 470 }
 471
 472 static void btrfsic_dev_state_init(struct btrfsic_dev_state *ds)
 473 {
 474         ds->magic_num = BTRFSIC_DEV2STATE_MAGIC_NUMBER;
 475         ds->bdev = NULL;
 476         ds->state = NULL;
 477         ds->name[0] = '\0';
 478         INIT_LIST_HEAD(&ds->collision_resolving_node);
 479         ds->last_flush_gen = 0;
 480         btrfsic_block_init(&ds->dummy_block_for_bio_bh_flush);
 481         ds->dummy_block_for_bio_bh_flush.is_iodone = 1;
 482         ds->dummy_block_for_bio_bh_flush.dev_state = ds;
 483 }
 484
 485 static struct btrfsic_dev_state *btrfsic_dev_state_alloc(void)
 486 {
 487         struct btrfsic_dev_state *ds;
 488
 489         ds = kzalloc(sizeof(*ds), GFP_NOFS);
 490         if (NULL != ds)
 491                 btrfsic_dev_state_init(ds);
 492
 493         return ds;
 494 }
 495
 496 static void btrfsic_dev_state_free(struct btrfsic_dev_state *ds)
 497 {
 498         BUG_ON(!(NULL == ds ||
 499                  BTRFSIC_DEV2STATE_MAGIC_NUMBER == ds->magic_num));
 500         kfree(ds);
 501 }
 502
 503 static void btrfsic_block_hashtable_init(struct btrfsic_block_hashtable *h)
 504 {
 505         int i;
 506
 507         for (i = 0; i < BTRFSIC_BLOCK_HASHTABLE_SIZE; i++)
 508                 INIT_LIST_HEAD(h->table + i);
 509 }
 510
 511 static void btrfsic_block_hashtable_add(struct btrfsic_block *b,
 512                                         struct btrfsic_block_hashtable *h)
 513 {
 514         const unsigned int hashval =
 515             (((unsigned int)(b->dev_bytenr >> 16)) ^
 516              ((unsigned int)((uintptr_t)b->dev_state->bdev))) &
 517              (BTRFSIC_BLOCK_HASHTABLE_SIZE - 1);
 518
 519         list_add(&b->collision_resolving_node, h->table + hashval);
 520 }
 521
 522 static void btrfsic_block_hashtable_remove(struct btrfsic_block *b)
 523 {
 524         list_del(&b->collision_resolving_node);
 525 }
 526
 527 static struct btrfsic_block *btrfsic_block_hashtable_lookup(
 528                 struct block_device *bdev,
 529                 u64 dev_bytenr,
 530                 struct btrfsic_block_hashtable *h)
 531 {
 532         const unsigned int hashval =
 533             (((unsigned int)(dev_bytenr >> 16)) ^
 534              ((unsigned int)((uintptr_t)bdev))) &
 535              (BTRFSIC_BLOCK_HASHTABLE_SIZE - 1);
 536         struct btrfsic_block *b;
 537
 538         list_for_each_entry(b, h->table + hashval, collision_resolving_node) {
 539                 if (b->dev_state->bdev == bdev && b->dev_bytenr == dev_bytenr)
 540                         return b;
 541         }
 542
 543         return NULL;
 544 }
 545
 546 static void btrfsic_block_link_hashtable_init(
 547                 struct btrfsic_block_link_hashtable *h)
 548 {
 549         int i;
 550
 551         for (i = 0; i < BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE; i++)
 552                 INIT_LIST_HEAD(h->table + i);
 553 }
 554
 555 static void btrfsic_block_link_hashtable_add(
 556                 struct btrfsic_block_link *l,
 557                 struct btrfsic_block_link_hashtable *h)
 558 {
 559         const unsigned int hashval =
 560             (((unsigned int)(l->block_ref_to->dev_bytenr >> 16)) ^
 561              ((unsigned int)(l->block_ref_from->dev_bytenr >> 16)) ^
 562              ((unsigned int)((uintptr_t)l->block_ref_to->dev_state->bdev)) ^
 563              ((unsigned int)((uintptr_t)l->block_ref_from->dev_state->bdev)))
 564              & (BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE - 1);
 565
 566         BUG_ON(NULL == l->block_ref_to);
 567         BUG_ON(NULL == l->block_ref_from);
 568         list_add(&l->collision_resolving_node, h->table + hashval);
 569 }
 570
 571 static void btrfsic_block_link_hashtable_remove(struct btrfsic_block_link *l)
 572 {
 573         list_del(&l->collision_resolving_node);
 574 }
 575
 576 static struct btrfsic_block_link *btrfsic_block_link_hashtable_lookup(
 577                 struct block_device *bdev_ref_to,
 578                 u64 dev_bytenr_ref_to,
 579                 struct block_device *bdev_ref_from,
 580                 u64 dev_bytenr_ref_from,
 581                 struct btrfsic_block_link_hashtable *h)
 582 {
 583         const unsigned int hashval =
 584             (((unsigned int)(dev_bytenr_ref_to >> 16)) ^
 585              ((unsigned int)(dev_bytenr_ref_from >> 16)) ^
 586              ((unsigned int)((uintptr_t)bdev_ref_to)) ^
 587              ((unsigned int)((uintptr_t)bdev_ref_from))) &
 588              (BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE - 1);
 589         struct btrfsic_block_link *l;
 590
 591         list_for_each_entry(l, h->table + hashval, collision_resolving_node) {
 592                 BUG_ON(NULL == l->block_ref_to);
 593                 BUG_ON(NULL == l->block_ref_from);
 594                 if (l->block_ref_to->dev_state->bdev == bdev_ref_to &&
 595                     l->block_ref_to->dev_bytenr == dev_bytenr_ref_to &&
 596                     l->block_ref_from->dev_state->bdev == bdev_ref_from &&
 597                     l->block_ref_from->dev_bytenr == dev_bytenr_ref_from)
 598                         return l;
 599         }
 600
 601         return NULL;
 602 }
 603
 604 static void btrfsic_dev_state_hashtable_init(
 605                 struct btrfsic_dev_state_hashtable *h)
 606 {
 607         int i;
 608
 609         for (i = 0; i < BTRFSIC_DEV2STATE_HASHTABLE_SIZE; i++)
 610                 INIT_LIST_HEAD(h->table + i);
 611 }
 612
 613 static void btrfsic_dev_state_hashtable_add(
 614                 struct btrfsic_dev_state *ds,
 615                 struct btrfsic_dev_state_hashtable *h)
 616 {
 617         const unsigned int hashval =
 618             (((unsigned int)((uintptr_t)ds->bdev)) &
 619              (BTRFSIC_DEV2STATE_HASHTABLE_SIZE - 1));
 620
 621         list_add(&ds->collision_resolving_node, h->table + hashval);
 622 }
 623
 624 static void btrfsic_dev_state_hashtable_remove(struct btrfsic_dev_state *ds)
 625 {
 626         list_del(&ds->collision_resolving_node);
 627 }
 628
 629 static struct btrfsic_dev_state *btrfsic_dev_state_hashtable_lookup(
 630                 struct block_device *bdev,
 631                 struct btrfsic_dev_state_hashtable *h)
 632 {
 633         const unsigned int hashval =
 634             (((unsigned int)((uintptr_t)bdev)) &
 635              (BTRFSIC_DEV2STATE_HASHTABLE_SIZE - 1));
 636         struct btrfsic_dev_state *ds;
 637
 638         list_for_each_entry(ds, h->table + hashval, collision_resolving_node) {
 639                 if (ds->bdev == bdev)
 640                         return ds;
 641         }
 642
 643         return NULL;
 644 }
 645
 646 static int btrfsic_process_superblock(struct btrfsic_state *state,
 647                                       struct btrfs_fs_devices *fs_devices)
 648 {
 649         struct btrfs_fs_info *fs_info = state->fs_info;
 650         struct btrfs_super_block *selected_super;
 651         struct list_head *dev_head = &fs_devices->devices;
 652         struct btrfs_device *device;
 653         struct btrfsic_dev_state *selected_dev_state = NULL;
 654         int ret = 0;
 655         int pass;
 656
 657         BUG_ON(NULL == state);
 658         selected_super = kzalloc(sizeof(*selected_super), GFP_NOFS);
 659         if (NULL == selected_super) {
 660                 pr_info("btrfsic: error, kmalloc failed!\n");
 661                 return -ENOMEM;
 662         }
 663
 664         list_for_each_entry(device, dev_head, dev_list) {
 665                 int i;
 666                 struct btrfsic_dev_state *dev_state;
 667
 668                 if (!device->bdev || !device->name)
 669                         continue;
 670
 671                 dev_state = btrfsic_dev_state_lookup(device->bdev);
 672                 BUG_ON(NULL == dev_state);
 673                 for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
 674                         ret = btrfsic_process_superblock_dev_mirror(
 675                                         state, dev_state, device, i,
 676                                         &selected_dev_state, selected_super);
 677                         if (0 != ret && 0 == i) {
 678                                 kfree(selected_super);
 679                                 return ret;
 680                         }
 681                 }
 682         }
 683
 684         if (NULL == state->latest_superblock) {
 685                 pr_info("btrfsic: no superblock found!\n");
 686                 kfree(selected_super);
 687                 return -1;
 688         }
 689
 690         state->csum_size = btrfs_super_csum_size(selected_super);
 691
 692         for (pass = 0; pass < 3; pass++) {
 693                 int num_copies;
 694                 int mirror_num;
 695                 u64 next_bytenr;
 696
 697                 switch (pass) {
 698                 case 0:
 699                         next_bytenr = btrfs_super_root(selected_super);
 700                         if (state->print_mask &
 701                             BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
 702                                 pr_info("root@%llu\n", next_bytenr);
 703                         break;
 704                 case 1:
 705                         next_bytenr = btrfs_super_chunk_root(selected_super);
 706                         if (state->print_mask &
 707                             BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
 708                                 pr_info("chunk@%llu\n", next_bytenr);
 709                         break;
 710                 case 2:
 711                         next_bytenr = btrfs_super_log_root(selected_super);
 712                         if (0 == next_bytenr)
 713                                 continue;
 714                         if (state->print_mask &
 715                             BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
 716                                 pr_info("log@%llu\n", next_bytenr);
 717                         break;
 718                 }
 719
 720                 num_copies = btrfs_num_copies(fs_info, next_bytenr,
 721                                               state->metablock_size);
 722                 if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
 723                         pr_info("num_copies(log_bytenr=%llu) = %d\n",
 724                                next_bytenr, num_copies);
 725
 726                 for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
 727                         struct btrfsic_block *next_block;
 728                         struct btrfsic_block_data_ctx tmp_next_block_ctx;
 729                         struct btrfsic_block_link *l;
 730
 731                         ret = btrfsic_map_block(state, next_bytenr,
 732                                                 state->metablock_size,
 733                                                 &tmp_next_block_ctx,
 734                                                 mirror_num);
 735                         if (ret) {
 736                                 pr_info("btrfsic: btrfsic_map_block(root @%llu, mirror %d) failed!\n",
 737                                        next_bytenr, mirror_num);
 738                                 kfree(selected_super);
 739                                 return -1;
 740                         }
 741
 742                         next_block = btrfsic_block_hashtable_lookup(
 743                                         tmp_next_block_ctx.dev->bdev,
 744                                         tmp_next_block_ctx.dev_bytenr,
 745                                         &state->block_hashtable);
 746                         BUG_ON(NULL == next_block);
 747
 748                         l = btrfsic_block_link_hashtable_lookup(
 749                                         tmp_next_block_ctx.dev->bdev,
 750                                         tmp_next_block_ctx.dev_bytenr,
 751                                         state->latest_superblock->dev_state->
 752                                         bdev,
 753                                         state->latest_superblock->dev_bytenr,
 754                                         &state->block_link_hashtable);
 755                         BUG_ON(NULL == l);
 756
 757                         ret = btrfsic_read_block(state, &tmp_next_block_ctx);
 758                         if (ret < (int)PAGE_SIZE) {
 759                                 pr_info("btrfsic: read @logical %llu failed!\n",
 760                                        tmp_next_block_ctx.start);
 761                                 btrfsic_release_block_ctx(&tmp_next_block_ctx);
 762                                 kfree(selected_super);
 763                                 return -1;
 764                         }
 765
 766                         ret = btrfsic_process_metablock(state,
 767                                                         next_block,
 768                                                         &tmp_next_block_ctx,
 769                                                         BTRFS_MAX_LEVEL + 3, 1);
 770                         btrfsic_release_block_ctx(&tmp_next_block_ctx);
 771                 }
 772         }
 773
 774         kfree(selected_super);
 775         return ret;
 776 }
 777
 778 static int btrfsic_process_superblock_dev_mirror(
 779                 struct btrfsic_state *state,
 780                 struct btrfsic_dev_state *dev_state,
 781                 struct btrfs_device *device,
 782                 int superblock_mirror_num,
 783                 struct btrfsic_dev_state **selected_dev_state,
 784                 struct btrfs_super_block *selected_super)
 785 {
 786         struct btrfs_fs_info *fs_info = state->fs_info;
 787         struct btrfs_super_block *super_tmp;
 788         u64 dev_bytenr;
 789         struct buffer_head *bh;
 790         struct btrfsic_block *superblock_tmp;
 791         int pass;
 792         struct block_device *const superblock_bdev = device->bdev;
 793
 794         /* super block bytenr is always the unmapped device bytenr */
 795         dev_bytenr = btrfs_sb_offset(superblock_mirror_num);
 796         if (dev_bytenr + BTRFS_SUPER_INFO_SIZE > device->commit_total_bytes)
 797                 return -1;
 798         bh = __bread(superblock_bdev, dev_bytenr / BTRFS_BDEV_BLOCKSIZE,
 799                      BTRFS_SUPER_INFO_SIZE);
 800         if (NULL == bh)
 801                 return -1;
 802         super_tmp = (struct btrfs_super_block *)
 803             (bh->b_data + (dev_bytenr & (BTRFS_BDEV_BLOCKSIZE - 1)));
 804
 805         if (btrfs_super_bytenr(super_tmp) != dev_bytenr ||
 806             btrfs_super_magic(super_tmp) != BTRFS_MAGIC ||
 807             memcmp(device->uuid, super_tmp->dev_item.uuid, BTRFS_UUID_SIZE) ||
 808             btrfs_super_nodesize(super_tmp) != state->metablock_size ||
 809             btrfs_super_sectorsize(super_tmp) != state->datablock_size) {
 810                 brelse(bh);
 811                 return 0;
 812         }
 813
 814         superblock_tmp =
 815             btrfsic_block_hashtable_lookup(superblock_bdev,
 816                                            dev_bytenr,
 817                                            &state->block_hashtable);
 818         if (NULL == superblock_tmp) {
 819                 superblock_tmp = btrfsic_block_alloc();
 820                 if (NULL == superblock_tmp) {
 821                         pr_info("btrfsic: error, kmalloc failed!\n");
 822                         brelse(bh);
 823                         return -1;
 824                 }
 825                 /* for superblock, only the dev_bytenr makes sense */
 826                 superblock_tmp->dev_bytenr = dev_bytenr;
 827                 superblock_tmp->dev_state = dev_state;
 828                 superblock_tmp->logical_bytenr = dev_bytenr;
 829                 superblock_tmp->generation = btrfs_super_generation(super_tmp);
 830                 superblock_tmp->is_metadata = 1;
 831                 superblock_tmp->is_superblock = 1;
 832                 superblock_tmp->is_iodone = 1;
 833                 superblock_tmp->never_written = 0;
 834                 superblock_tmp->mirror_num = 1 + superblock_mirror_num;
 835                 if (state->print_mask & BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE)
 836                         btrfs_info_in_rcu(fs_info,
 837                                 "new initial S-block (bdev %p, %s) @%llu (%s/%llu/%d)",
 838                                      superblock_bdev,
 839                                      rcu_str_deref(device->name), dev_bytenr,
 840                                      dev_state->name, dev_bytenr,
 841                                      superblock_mirror_num);
 842                 list_add(&superblock_tmp->all_blocks_node,
 843                          &state->all_blocks_list);
 844                 btrfsic_block_hashtable_add(superblock_tmp,
 845                                             &state->block_hashtable);
 846         }
 847
 848         /* select the one with the highest generation field */
 849         if (btrfs_super_generation(super_tmp) >
 850             state->max_superblock_generation ||
 851             0 == state->max_superblock_generation) {
 852                 memcpy(selected_super, super_tmp, sizeof(*selected_super));
 853                 *selected_dev_state = dev_state;
 854                 state->max_superblock_generation =
 855                     btrfs_super_generation(super_tmp);
 856                 state->latest_superblock = superblock_tmp;
 857         }
 858
 859         for (pass = 0; pass < 3; pass++) {
 860                 u64 next_bytenr;
 861                 int num_copies;
 862                 int mirror_num;
 863                 const char *additional_string = NULL;
 864                 struct btrfs_disk_key tmp_disk_key;
 865
 866                 tmp_disk_key.type = BTRFS_ROOT_ITEM_KEY;
 867                 tmp_disk_key.offset = 0;
 868                 switch (pass) {
 869                 case 0:
 870                         btrfs_set_disk_key_objectid(&tmp_disk_key,
 871                                                     BTRFS_ROOT_TREE_OBJECTID);
 872                         additional_string = "initial root ";
 873                         next_bytenr = btrfs_super_root(super_tmp);
 874                         break;
 875                 case 1:
 876                         btrfs_set_disk_key_objectid(&tmp_disk_key,
 877                                                     BTRFS_CHUNK_TREE_OBJECTID);
 878                         additional_string = "initial chunk ";
 879                         next_bytenr = btrfs_super_chunk_root(super_tmp);
 880                         break;
 881                 case 2:
 882                         btrfs_set_disk_key_objectid(&tmp_disk_key,
 883                                                     BTRFS_TREE_LOG_OBJECTID);
 884                         additional_string = "initial log ";
 885                         next_bytenr = btrfs_super_log_root(super_tmp);
 886                         if (0 == next_bytenr)
 887                                 continue;
 888                         break;
 889                 }
 890
 891                 num_copies = btrfs_num_copies(fs_info, next_bytenr,
 892                                               state->metablock_size);
 893                 if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
 894                         pr_info("num_copies(log_bytenr=%llu) = %d\n",
 895                                next_bytenr, num_copies);
 896                 for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
 897                         struct btrfsic_block *next_block;
 898                         struct btrfsic_block_data_ctx tmp_next_block_ctx;
 899                         struct btrfsic_block_link *l;
 900
 901                         if (btrfsic_map_block(state, next_bytenr,
 902                                               state->metablock_size,
 903                                               &tmp_next_block_ctx,
 904                                               mirror_num)) {
 905                                 pr_info("btrfsic: btrfsic_map_block(bytenr @%llu, mirror %d) failed!\n",
 906                                        next_bytenr, mirror_num);
 907                                 brelse(bh);
 908                                 return -1;
 909                         }
 910
 911                         next_block = btrfsic_block_lookup_or_add(
 912                                         state, &tmp_next_block_ctx,
 913                                         additional_string, 1, 1, 0,
 914                                         mirror_num, NULL);
 915                         if (NULL == next_block) {
 916                                 btrfsic_release_block_ctx(&tmp_next_block_ctx);
 917                                 brelse(bh);
 918                                 return -1;
 919                         }
 920
 921                         next_block->disk_key = tmp_disk_key;
 922                         next_block->generation = BTRFSIC_GENERATION_UNKNOWN;
 923                         l = btrfsic_block_link_lookup_or_add(
 924                                         state, &tmp_next_block_ctx,
 925                                         next_block, superblock_tmp,
 926                                         BTRFSIC_GENERATION_UNKNOWN);
 927                         btrfsic_release_block_ctx(&tmp_next_block_ctx);
 928                         if (NULL == l) {
 929                                 brelse(bh);
 930                                 return -1;
 931                         }
 932                 }
 933         }
 934         if (state->print_mask & BTRFSIC_PRINT_MASK_INITIAL_ALL_TREES)
 935                 btrfsic_dump_tree_sub(state, superblock_tmp, 0);
 936
 937         brelse(bh);
 938         return 0;
 939 }
 940
 941 static struct btrfsic_stack_frame *btrfsic_stack_frame_alloc(void)
 942 {
 943         struct btrfsic_stack_frame *sf;
 944
 945         sf = kzalloc(sizeof(*sf), GFP_NOFS);
 946         if (NULL == sf)
 947                 pr_info("btrfsic: alloc memory failed!\n");
 948         else
 949                 sf->magic = BTRFSIC_BLOCK_STACK_FRAME_MAGIC_NUMBER;
 950         return sf;
 951 }
 952
 953 static void btrfsic_stack_frame_free(struct btrfsic_stack_frame *sf)
 954 {
 955         BUG_ON(!(NULL == sf ||
 956                  BTRFSIC_BLOCK_STACK_FRAME_MAGIC_NUMBER == sf->magic));
 957         kfree(sf);
 958 }
 959
 960 static int btrfsic_process_metablock(
 961                 struct btrfsic_state *state,
 962                 struct btrfsic_block *const first_block,
 963                 struct btrfsic_block_data_ctx *const first_block_ctx,
 964                 int first_limit_nesting, int force_iodone_flag)
 965 {
 966         struct btrfsic_stack_frame initial_stack_frame = { 0 };
 967         struct btrfsic_stack_frame *sf;
 968         struct btrfsic_stack_frame *next_stack;
 969         struct btrfs_header *const first_hdr =
 970                 (struct btrfs_header *)first_block_ctx->datav[0];
 971
 972         BUG_ON(!first_hdr);
 973         sf = &initial_stack_frame;
 974         sf->error = 0;
 975         sf->i = -1;
 976         sf->limit_nesting = first_limit_nesting;
 977         sf->block = first_block;
 978         sf->block_ctx = first_block_ctx;
 979         sf->next_block = NULL;
 980         sf->hdr = first_hdr;
 981         sf->prev = NULL;
 982
 983 continue_with_new_stack_frame:
 984         sf->block->generation = le64_to_cpu(sf->hdr->generation);
 985         if (0 == sf->hdr->level) {
 986                 struct btrfs_leaf *const leafhdr =
 987                     (struct btrfs_leaf *)sf->hdr;
 988
 989                 if (-1 == sf->i) {
 990                         sf->nr = btrfs_stack_header_nritems(&leafhdr->header);
 991
 992                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
 993                                 pr_info("leaf %llu items %d generation %llu owner %llu\n",
 994                                        sf->block_ctx->start, sf->nr,
 995                                        btrfs_stack_header_generation(
 996                                                &leafhdr->header),
 997                                        btrfs_stack_header_owner(
 998                                                &leafhdr->header));
 999                 }
1000
1001 continue_with_current_leaf_stack_frame:
1002                 if (0 == sf->num_copies || sf->mirror_num > sf->num_copies) {
1003                         sf->i++;
1004                         sf->num_copies = 0;
1005                 }
1006
1007                 if (sf->i < sf->nr) {
1008                         struct btrfs_item disk_item;
1009                         u32 disk_item_offset =
1010                                 (uintptr_t)(leafhdr->items + sf->i) -
1011                                 (uintptr_t)leafhdr;
1012                         struct btrfs_disk_key *disk_key;
1013                         u8 type;
1014                         u32 item_offset;
1015                         u32 item_size;
1016
1017                         if (disk_item_offset + sizeof(struct btrfs_item) >
1018                             sf->block_ctx->len) {
1019 leaf_item_out_of_bounce_error:
1020                                 pr_info("btrfsic: leaf item out of bounce at logical %llu, dev %s\n",
1021                                        sf->block_ctx->start,
1022                                        sf->block_ctx->dev->name);
1023                                 goto one_stack_frame_backwards;
1024                         }
1025                         btrfsic_read_from_block_data(sf->block_ctx,
1026                                                      &disk_item,
1027                                                      disk_item_offset,
1028                                                      sizeof(struct btrfs_item));
1029                         item_offset = btrfs_stack_item_offset(&disk_item);
1030                         item_size = btrfs_stack_item_size(&disk_item);
1031                         disk_key = &disk_item.key;
1032                         type = btrfs_disk_key_type(disk_key);
1033
1034                         if (BTRFS_ROOT_ITEM_KEY == type) {
1035                                 struct btrfs_root_item root_item;
1036                                 u32 root_item_offset;
1037                                 u64 next_bytenr;
1038
1039                                 root_item_offset = item_offset +
1040                                         offsetof(struct btrfs_leaf, items);
1041                                 if (root_item_offset + item_size >
1042                                     sf->block_ctx->len)
1043                                         goto leaf_item_out_of_bounce_error;
1044                                 btrfsic_read_from_block_data(
1045                                         sf->block_ctx, &root_item,
1046                                         root_item_offset,
1047                                         item_size);
1048                                 next_bytenr = btrfs_root_bytenr(&root_item);
1049
1050                                 sf->error =
1051                                     btrfsic_create_link_to_next_block(
1052                                                 state,
1053                                                 sf->block,
1054                                                 sf->block_ctx,
1055                                                 next_bytenr,
1056                                                 sf->limit_nesting,
1057                                                 &sf->next_block_ctx,
1058                                                 &sf->next_block,
1059                                                 force_iodone_flag,
1060                                                 &sf->num_copies,
1061                                                 &sf->mirror_num,
1062                                                 disk_key,
1063                                                 btrfs_root_generation(
1064                                                 &root_item));
1065                                 if (sf->error)
1066                                         goto one_stack_frame_backwards;
1067
1068                                 if (NULL != sf->next_block) {
1069                                         struct btrfs_header *const next_hdr =
1070                                             (struct btrfs_header *)
1071                                             sf->next_block_ctx.datav[0];
1072
1073                                         next_stack =
1074                                             btrfsic_stack_frame_alloc();
1075                                         if (NULL == next_stack) {
1076                                                 sf->error = -1;
1077                                                 btrfsic_release_block_ctx(
1078                                                                 &sf->
1079                                                                 next_block_ctx);
1080                                                 goto one_stack_frame_backwards;
1081                                         }
1082
1083                                         next_stack->i = -1;
1084                                         next_stack->block = sf->next_block;
1085                                         next_stack->block_ctx =
1086                                             &sf->next_block_ctx;
1087                                         next_stack->next_block = NULL;
1088                                         next_stack->hdr = next_hdr;
1089                                         next_stack->limit_nesting =
1090                                             sf->limit_nesting - 1;
1091                                         next_stack->prev = sf;
1092                                         sf = next_stack;
1093                                         goto continue_with_new_stack_frame;
1094                                 }
1095                         } else if (BTRFS_EXTENT_DATA_KEY == type &&
1096                                    state->include_extent_data) {
1097                                 sf->error = btrfsic_handle_extent_data(
1098                                                 state,
1099                                                 sf->block,
1100                                                 sf->block_ctx,
1101                                                 item_offset,
1102                                                 force_iodone_flag);
1103                                 if (sf->error)
1104                                         goto one_stack_frame_backwards;
1105                         }
1106
1107                         goto continue_with_current_leaf_stack_frame;
1108                 }
1109         } else {
1110                 struct btrfs_node *const nodehdr = (struct btrfs_node *)sf->hdr;
1111
1112                 if (-1 == sf->i) {
1113                         sf->nr = btrfs_stack_header_nritems(&nodehdr->header);
1114
1115                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1116                                 pr_info("node %llu level %d items %d generation %llu owner %llu\n",
1117                                        sf->block_ctx->start,
1118                                        nodehdr->header.level, sf->nr,
1119                                        btrfs_stack_header_generation(
1120                                        &nodehdr->header),
1121                                        btrfs_stack_header_owner(
1122                                        &nodehdr->header));
1123                 }
1124
1125 continue_with_current_node_stack_frame:
1126                 if (0 == sf->num_copies || sf->mirror_num > sf->num_copies) {
1127                         sf->i++;
1128                         sf->num_copies = 0;
1129                 }
1130
1131                 if (sf->i < sf->nr) {
1132                         struct btrfs_key_ptr key_ptr;
1133                         u32 key_ptr_offset;
1134                         u64 next_bytenr;
1135
1136                         key_ptr_offset = (uintptr_t)(nodehdr->ptrs + sf->i) -
1137                                           (uintptr_t)nodehdr;
1138                         if (key_ptr_offset + sizeof(struct btrfs_key_ptr) >
1139                             sf->block_ctx->len) {
1140                                 pr_info("btrfsic: node item out of bounce at logical %llu, dev %s\n",
1141                                        sf->block_ctx->start,
1142                                        sf->block_ctx->dev->name);
1143                                 goto one_stack_frame_backwards;
1144                         }
1145                         btrfsic_read_from_block_data(
1146                                 sf->block_ctx, &key_ptr, key_ptr_offset,
1147                                 sizeof(struct btrfs_key_ptr));
1148                         next_bytenr = btrfs_stack_key_blockptr(&key_ptr);
1149
1150                         sf->error = btrfsic_create_link_to_next_block(
1151                                         state,
1152                                         sf->block,
1153                                         sf->block_ctx,
1154                                         next_bytenr,
1155                                         sf->limit_nesting,
1156                                         &sf->next_block_ctx,
1157                                         &sf->next_block,
1158                                         force_iodone_flag,
1159                                         &sf->num_copies,
1160                                         &sf->mirror_num,
1161                                         &key_ptr.key,
1162                                         btrfs_stack_key_generation(&key_ptr));
1163                         if (sf->error)
1164                                 goto one_stack_frame_backwards;
1165
1166                         if (NULL != sf->next_block) {
1167                                 struct btrfs_header *const next_hdr =
1168                                     (struct btrfs_header *)
1169                                     sf->next_block_ctx.datav[0];
1170
1171                                 next_stack = btrfsic_stack_frame_alloc();
1172                                 if (NULL == next_stack) {
1173                                         sf->error = -1;
1174                                         goto one_stack_frame_backwards;
1175                                 }
1176
1177                                 next_stack->i = -1;
1178                                 next_stack->block = sf->next_block;
1179                                 next_stack->block_ctx = &sf->next_block_ctx;
1180                                 next_stack->next_block = NULL;
1181                                 next_stack->hdr = next_hdr;
1182                                 next_stack->limit_nesting =
1183                                     sf->limit_nesting - 1;
1184                                 next_stack->prev = sf;
1185                                 sf = next_stack;
1186                                 goto continue_with_new_stack_frame;
1187                         }
1188
1189                         goto continue_with_current_node_stack_frame;
1190                 }
1191         }
1192
1193 one_stack_frame_backwards:
1194         if (NULL != sf->prev) {
1195                 struct btrfsic_stack_frame *const prev = sf->prev;
1196
1197                 /* the one for the initial block is freed in the caller */
1198                 btrfsic_release_block_ctx(sf->block_ctx);
1199
1200                 if (sf->error) {
1201                         prev->error = sf->error;
1202                         btrfsic_stack_frame_free(sf);
1203                         sf = prev;
1204                         goto one_stack_frame_backwards;
1205                 }
1206
1207                 btrfsic_stack_frame_free(sf);
1208                 sf = prev;
1209                 goto continue_with_new_stack_frame;
1210         } else {
1211                 BUG_ON(&initial_stack_frame != sf);
1212         }
1213
1214         return sf->error;
1215 }
1216
1217 static void btrfsic_read_from_block_data(
1218         struct btrfsic_block_data_ctx *block_ctx,
1219         void *dstv, u32 offset, size_t len)
1220 {
1221         size_t cur;
1222         size_t offset_in_page;
1223         char *kaddr;
1224         char *dst = (char *)dstv;
1225         size_t start_offset = block_ctx->start & ((u64)PAGE_SIZE - 1);
1226         unsigned long i = (start_offset + offset) >> PAGE_SHIFT;
1227
1228         WARN_ON(offset + len > block_ctx->len);
1229         offset_in_page = (start_offset + offset) & (PAGE_SIZE - 1);
1230
1231         while (len > 0) {
1232                 cur = min(len, ((size_t)PAGE_SIZE - offset_in_page));
1233                 BUG_ON(i >= DIV_ROUND_UP(block_ctx->len, PAGE_SIZE));
1234                 kaddr = block_ctx->datav[i];
1235                 memcpy(dst, kaddr + offset_in_page, cur);
1236
1237                 dst += cur;
1238                 len -= cur;
1239                 offset_in_page = 0;
1240                 i++;
1241         }
1242 }
1243
1244 static int btrfsic_create_link_to_next_block(
1245                 struct btrfsic_state *state,
1246                 struct btrfsic_block *block,
1247                 struct btrfsic_block_data_ctx *block_ctx,
1248                 u64 next_bytenr,
1249                 int limit_nesting,
1250                 struct btrfsic_block_data_ctx *next_block_ctx,
1251                 struct btrfsic_block **next_blockp,
1252                 int force_iodone_flag,
1253                 int *num_copiesp, int *mirror_nump,
1254                 struct btrfs_disk_key *disk_key,
1255                 u64 parent_generation)
1256 {
1257         struct btrfs_fs_info *fs_info = state->fs_info;
1258         struct btrfsic_block *next_block = NULL;
1259         int ret;
1260         struct btrfsic_block_link *l;
1261         int did_alloc_block_link;
1262         int block_was_created;
1263
1264         *next_blockp = NULL;
1265         if (0 == *num_copiesp) {
1266                 *num_copiesp = btrfs_num_copies(fs_info, next_bytenr,
1267                                                 state->metablock_size);
1268                 if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
1269                         pr_info("num_copies(log_bytenr=%llu) = %d\n",
1270                                next_bytenr, *num_copiesp);
1271                 *mirror_nump = 1;
1272         }
1273
1274         if (*mirror_nump > *num_copiesp)
1275                 return 0;
1276
1277         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1278                 pr_info("btrfsic_create_link_to_next_block(mirror_num=%d)\n",
1279                        *mirror_nump);
1280         ret = btrfsic_map_block(state, next_bytenr,
1281                                 state->metablock_size,
1282                                 next_block_ctx, *mirror_nump);
1283         if (ret) {
1284                 pr_info("btrfsic: btrfsic_map_block(@%llu, mirror=%d) failed!\n",
1285                        next_bytenr, *mirror_nump);
1286                 btrfsic_release_block_ctx(next_block_ctx);
1287                 *next_blockp = NULL;
1288                 return -1;
1289         }
1290
1291         next_block = btrfsic_block_lookup_or_add(state,
1292                                                  next_block_ctx, "referenced ",
1293                                                  1, force_iodone_flag,
1294                                                  !force_iodone_flag,
1295                                                  *mirror_nump,
1296                                                  &block_was_created);
1297         if (NULL == next_block) {
1298                 btrfsic_release_block_ctx(next_block_ctx);
1299                 *next_blockp = NULL;
1300                 return -1;
1301         }
1302         if (block_was_created) {
1303                 l = NULL;
1304                 next_block->generation = BTRFSIC_GENERATION_UNKNOWN;
1305         } else {
1306                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE) {
1307                         if (next_block->logical_bytenr != next_bytenr &&
1308                             !(!next_block->is_metadata &&
1309                               0 == next_block->logical_bytenr))
1310                                 pr_info("Referenced block @%llu (%s/%llu/%d) found in hash table, %c, bytenr mismatch (!= stored %llu).\n",
1311                                        next_bytenr, next_block_ctx->dev->name,
1312                                        next_block_ctx->dev_bytenr, *mirror_nump,
1313                                        btrfsic_get_block_type(state,
1314                                                               next_block),
1315                                        next_block->logical_bytenr);
1316                         else
1317                                 pr_info("Referenced block @%llu (%s/%llu/%d) found in hash table, %c.\n",
1318                                        next_bytenr, next_block_ctx->dev->name,
1319                                        next_block_ctx->dev_bytenr, *mirror_nump,
1320                                        btrfsic_get_block_type(state,
1321                                                               next_block));
1322                 }
1323                 next_block->logical_bytenr = next_bytenr;
1324
1325                 next_block->mirror_num = *mirror_nump;
1326                 l = btrfsic_block_link_hashtable_lookup(
1327                                 next_block_ctx->dev->bdev,
1328                                 next_block_ctx->dev_bytenr,
1329                                 block_ctx->dev->bdev,
1330                                 block_ctx->dev_bytenr,
1331                                 &state->block_link_hashtable);
1332         }
1333
1334         next_block->disk_key = *disk_key;
1335         if (NULL == l) {
1336                 l = btrfsic_block_link_alloc();
1337                 if (NULL == l) {
1338                         pr_info("btrfsic: error, kmalloc failed!\n");
1339                         btrfsic_release_block_ctx(next_block_ctx);
1340                         *next_blockp = NULL;
1341                         return -1;
1342                 }
1343
1344                 did_alloc_block_link = 1;
1345                 l->block_ref_to = next_block;
1346                 l->block_ref_from = block;
1347                 l->ref_cnt = 1;
1348                 l->parent_generation = parent_generation;
1349
1350                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1351                         btrfsic_print_add_link(state, l);
1352
1353                 list_add(&l->node_ref_to, &block->ref_to_list);
1354                 list_add(&l->node_ref_from, &next_block->ref_from_list);
1355
1356                 btrfsic_block_link_hashtable_add(l,
1357                                                  &state->block_link_hashtable);
1358         } else {
1359                 did_alloc_block_link = 0;
1360                 if (0 == limit_nesting) {
1361                         l->ref_cnt++;
1362                         l->parent_generation = parent_generation;
1363                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1364                                 btrfsic_print_add_link(state, l);
1365                 }
1366         }
1367
1368         if (limit_nesting > 0 && did_alloc_block_link) {
1369                 ret = btrfsic_read_block(state, next_block_ctx);
1370                 if (ret < (int)next_block_ctx->len) {
1371                         pr_info("btrfsic: read block @logical %llu failed!\n",
1372                                next_bytenr);
1373                         btrfsic_release_block_ctx(next_block_ctx);
1374                         *next_blockp = NULL;
1375                         return -1;
1376                 }
1377
1378                 *next_blockp = next_block;
1379         } else {
1380                 *next_blockp = NULL;
1381         }
1382         (*mirror_nump)++;
1383
1384         return 0;
1385 }
1386
1387 static int btrfsic_handle_extent_data(
1388                 struct btrfsic_state *state,
1389                 struct btrfsic_block *block,
1390                 struct btrfsic_block_data_ctx *block_ctx,
1391                 u32 item_offset, int force_iodone_flag)
1392 {
1393         struct btrfs_fs_info *fs_info = state->fs_info;
1394         struct btrfs_file_extent_item file_extent_item;
1395         u64 file_extent_item_offset;
1396         u64 next_bytenr;
1397         u64 num_bytes;
1398         u64 generation;
1399         struct btrfsic_block_link *l;
1400         int ret;
1401
1402         file_extent_item_offset = offsetof(struct btrfs_leaf, items) +
1403                                   item_offset;
1404         if (file_extent_item_offset +
1405             offsetof(struct btrfs_file_extent_item, disk_num_bytes) >
1406             block_ctx->len) {
1407                 pr_info("btrfsic: file item out of bounce at logical %llu, dev %s\n",
1408                        block_ctx->start, block_ctx->dev->name);
1409                 return -1;
1410         }
1411
1412         btrfsic_read_from_block_data(block_ctx, &file_extent_item,
1413                 file_extent_item_offset,
1414                 offsetof(struct btrfs_file_extent_item, disk_num_bytes));
1415         if (BTRFS_FILE_EXTENT_REG != file_extent_item.type ||
1416             btrfs_stack_file_extent_disk_bytenr(&file_extent_item) == 0) {
1417                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERY_VERBOSE)
1418                         pr_info("extent_data: type %u, disk_bytenr = %llu\n",
1419                                file_extent_item.type,
1420                                btrfs_stack_file_extent_disk_bytenr(
1421                                &file_extent_item));
1422                 return 0;
1423         }
1424
1425         if (file_extent_item_offset + sizeof(struct btrfs_file_extent_item) >
1426             block_ctx->len) {
1427                 pr_info("btrfsic: file item out of bounce at logical %llu, dev %s\n",
1428                        block_ctx->start, block_ctx->dev->name);
1429                 return -1;
1430         }
1431         btrfsic_read_from_block_data(block_ctx, &file_extent_item,
1432                                      file_extent_item_offset,
1433                                      sizeof(struct btrfs_file_extent_item));
1434         next_bytenr = btrfs_stack_file_extent_disk_bytenr(&file_extent_item);
1435         if (btrfs_stack_file_extent_compression(&file_extent_item) ==
1436             BTRFS_COMPRESS_NONE) {
1437                 next_bytenr += btrfs_stack_file_extent_offset(&file_extent_item);
1438                 num_bytes = btrfs_stack_file_extent_num_bytes(&file_extent_item);
1439         } else {
1440                 num_bytes = btrfs_stack_file_extent_disk_num_bytes(&file_extent_item);
1441         }
1442         generation = btrfs_stack_file_extent_generation(&file_extent_item);
1443
1444         if (state->print_mask & BTRFSIC_PRINT_MASK_VERY_VERBOSE)
1445                 pr_info("extent_data: type %u, disk_bytenr = %llu, offset = %llu, num_bytes = %llu\n",
1446                        file_extent_item.type,
1447                        btrfs_stack_file_extent_disk_bytenr(&file_extent_item),
1448                        btrfs_stack_file_extent_offset(&file_extent_item),
1449                        num_bytes);
1450         while (num_bytes > 0) {
1451                 u32 chunk_len;
1452                 int num_copies;
1453                 int mirror_num;
1454
1455                 if (num_bytes > state->datablock_size)
1456                         chunk_len = state->datablock_size;
1457                 else
1458                         chunk_len = num_bytes;
1459
1460                 num_copies = btrfs_num_copies(fs_info, next_bytenr,
1461                                               state->datablock_size);
1462                 if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
1463                         pr_info("num_copies(log_bytenr=%llu) = %d\n",
1464                                next_bytenr, num_copies);
1465                 for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
1466                         struct btrfsic_block_data_ctx next_block_ctx;
1467                         struct btrfsic_block *next_block;
1468                         int block_was_created;
1469
1470                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1471                                 pr_info("btrfsic_handle_extent_data(mirror_num=%d)\n",
1472                                         mirror_num);
1473                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERY_VERBOSE)
1474                                 pr_info("\tdisk_bytenr = %llu, num_bytes %u\n",
1475                                        next_bytenr, chunk_len);
1476                         ret = btrfsic_map_block(state, next_bytenr,
1477                                                 chunk_len, &next_block_ctx,
1478                                                 mirror_num);
1479                         if (ret) {
1480                                 pr_info("btrfsic: btrfsic_map_block(@%llu, mirror=%d) failed!\n",
1481                                        next_bytenr, mirror_num);
1482                                 return -1;
1483                         }
1484
1485                         next_block = btrfsic_block_lookup_or_add(
1486                                         state,
1487                                         &next_block_ctx,
1488                                         "referenced ",
1489                                         0,
1490                                         force_iodone_flag,
1491                                         !force_iodone_flag,
1492                                         mirror_num,
1493                                         &block_was_created);
1494                         if (NULL == next_block) {
1495                                 pr_info("btrfsic: error, kmalloc failed!\n");
1496                                 btrfsic_release_block_ctx(&next_block_ctx);
1497                                 return -1;
1498                         }
1499                         if (!block_was_created) {
1500                                 if ((state->print_mask &
1501                                      BTRFSIC_PRINT_MASK_VERBOSE) &&
1502                                     next_block->logical_bytenr != next_bytenr &&
1503                                     !(!next_block->is_metadata &&
1504                                       0 == next_block->logical_bytenr)) {
1505                                         pr_info("Referenced block @%llu (%s/%llu/%d) found in hash table, D, bytenr mismatch (!= stored %llu).\n",
1506                                                next_bytenr,
1507                                                next_block_ctx.dev->name,
1508                                                next_block_ctx.dev_bytenr,
1509                                                mirror_num,
1510                                                next_block->logical_bytenr);
1511                                 }
1512                                 next_block->logical_bytenr = next_bytenr;
1513                                 next_block->mirror_num = mirror_num;
1514                         }
1515
1516                         l = btrfsic_block_link_lookup_or_add(state,
1517                                                              &next_block_ctx,
1518                                                              next_block, block,
1519                                                              generation);
1520                         btrfsic_release_block_ctx(&next_block_ctx);
1521                         if (NULL == l)
1522                                 return -1;
1523                 }
1524
1525                 next_bytenr += chunk_len;
1526                 num_bytes -= chunk_len;
1527         }
1528
1529         return 0;
1530 }
1531
1532 static int btrfsic_map_block(struct btrfsic_state *state, u64 bytenr, u32 len,
1533                              struct btrfsic_block_data_ctx *block_ctx_out,
1534                              int mirror_num)
1535 {
1536         struct btrfs_fs_info *fs_info = state->fs_info;
1537         int ret;
1538         u64 length;
1539         struct btrfs_bio *multi = NULL;
1540         struct btrfs_device *device;
1541
1542         length = len;
1543         ret = btrfs_map_block(fs_info, BTRFS_MAP_READ,
1544                               bytenr, &length, &multi, mirror_num);
1545
1546         if (ret) {
1547                 block_ctx_out->start = 0;
1548                 block_ctx_out->dev_bytenr = 0;
1549                 block_ctx_out->len = 0;
1550                 block_ctx_out->dev = NULL;
1551                 block_ctx_out->datav = NULL;
1552                 block_ctx_out->pagev = NULL;
1553                 block_ctx_out->mem_to_free = NULL;
1554
1555                 return ret;
1556         }
1557
1558         device = multi->stripes[0].dev;
1559         block_ctx_out->dev = btrfsic_dev_state_lookup(device->bdev);
1560         block_ctx_out->dev_bytenr = multi->stripes[0].physical;
1561         block_ctx_out->start = bytenr;
1562         block_ctx_out->len = len;
1563         block_ctx_out->datav = NULL;
1564         block_ctx_out->pagev = NULL;
1565         block_ctx_out->mem_to_free = NULL;
1566
1567         kfree(multi);
1568         if (NULL == block_ctx_out->dev) {
1569                 ret = -ENXIO;
1570                 pr_info("btrfsic: error, cannot lookup dev (#1)!\n");
1571         }
1572
1573         return ret;
1574 }
1575
1576 static void btrfsic_release_block_ctx(struct btrfsic_block_data_ctx *block_ctx)
1577 {
1578         if (block_ctx->mem_to_free) {
1579                 unsigned int num_pages;
1580
1581                 BUG_ON(!block_ctx->datav);
1582                 BUG_ON(!block_ctx->pagev);
1583                 num_pages = (block_ctx->len + (u64)PAGE_SIZE - 1) >>
1584                             PAGE_SHIFT;
1585                 while (num_pages > 0) {
1586                         num_pages--;
1587                         if (block_ctx->datav[num_pages]) {
1588                                 kunmap(block_ctx->pagev[num_pages]);
1589                                 block_ctx->datav[num_pages] = NULL;
1590                         }
1591                         if (block_ctx->pagev[num_pages]) {
1592                                 __free_page(block_ctx->pagev[num_pages]);
1593                                 block_ctx->pagev[num_pages] = NULL;
1594                         }
1595                 }
1596
1597                 kfree(block_ctx->mem_to_free);
1598                 block_ctx->mem_to_free = NULL;
1599                 block_ctx->pagev = NULL;
1600                 block_ctx->datav = NULL;
1601         }
1602 }
1603
1604 static int btrfsic_read_block(struct btrfsic_state *state,
1605                               struct btrfsic_block_data_ctx *block_ctx)
1606 {
1607         unsigned int num_pages;
1608         unsigned int i;
1609         u64 dev_bytenr;
1610         int ret;
1611
1612         BUG_ON(block_ctx->datav);
1613         BUG_ON(block_ctx->pagev);
1614         BUG_ON(block_ctx->mem_to_free);
1615         if (block_ctx->dev_bytenr & ((u64)PAGE_SIZE - 1)) {
1616                 pr_info("btrfsic: read_block() with unaligned bytenr %llu\n",
1617                        block_ctx->dev_bytenr);
1618                 return -1;
1619         }
1620
1621         num_pages = (block_ctx->len + (u64)PAGE_SIZE - 1) >>
1622                     PAGE_SHIFT;
1623         block_ctx->mem_to_free = kzalloc((sizeof(*block_ctx->datav) +
1624                                           sizeof(*block_ctx->pagev)) *
1625                                          num_pages, GFP_NOFS);
1626         if (!block_ctx->mem_to_free)
1627                 return -ENOMEM;
1628         block_ctx->datav = block_ctx->mem_to_free;
1629         block_ctx->pagev = (struct page **)(block_ctx->datav + num_pages);
1630         for (i = 0; i < num_pages; i++) {
1631                 block_ctx->pagev[i] = alloc_page(GFP_NOFS);
1632                 if (!block_ctx->pagev[i])
1633                         return -1;
1634         }
1635
1636         dev_bytenr = block_ctx->dev_bytenr;
1637         for (i = 0; i < num_pages;) {
1638                 struct bio *bio;
1639                 unsigned int j;
1640
1641                 bio = btrfs_io_bio_alloc(num_pages - i);
1642                 bio->bi_bdev = block_ctx->dev->bdev;
1643                 bio->bi_iter.bi_sector = dev_bytenr >> 9;
1644                 bio_set_op_attrs(bio, REQ_OP_READ, 0);
1645
1646                 for (j = i; j < num_pages; j++) {
1647                         ret = bio_add_page(bio, block_ctx->pagev[j],
1648                                            PAGE_SIZE, 0);
1649                         if (PAGE_SIZE != ret)
1650                                 break;
1651                 }
1652                 if (j == i) {
1653                         pr_info("btrfsic: error, failed to add a single page!\n");
1654                         return -1;
1655                 }
1656                 if (submit_bio_wait(bio)) {
1657                         pr_info("btrfsic: read error at logical %llu dev %s!\n",
1658                                block_ctx->start, block_ctx->dev->name);
1659                         bio_put(bio);
1660                         return -1;
1661                 }
1662                 bio_put(bio);
1663                 dev_bytenr += (j - i) * PAGE_SIZE;
1664                 i = j;
1665         }
1666         for (i = 0; i < num_pages; i++)
1667                 block_ctx->datav[i] = kmap(block_ctx->pagev[i]);
1668
1669         return block_ctx->len;
1670 }
1671
1672 static void btrfsic_dump_database(struct btrfsic_state *state)
1673 {
1674         const struct btrfsic_block *b_all;
1675
1676         BUG_ON(NULL == state);
1677
1678         pr_info("all_blocks_list:\n");
1679         list_for_each_entry(b_all, &state->all_blocks_list, all_blocks_node) {
1680                 const struct btrfsic_block_link *l;
1681
1682                 pr_info("%c-block @%llu (%s/%llu/%d)\n",
1683                        btrfsic_get_block_type(state, b_all),
1684                        b_all->logical_bytenr, b_all->dev_state->name,
1685                        b_all->dev_bytenr, b_all->mirror_num);
1686
1687                 list_for_each_entry(l, &b_all->ref_to_list, node_ref_to) {
1688                         pr_info(" %c @%llu (%s/%llu/%d) refers %u* to %c @%llu (%s/%llu/%d)\n",
1689                                btrfsic_get_block_type(state, b_all),
1690                                b_all->logical_bytenr, b_all->dev_state->name,
1691                                b_all->dev_bytenr, b_all->mirror_num,
1692                                l->ref_cnt,
1693                                btrfsic_get_block_type(state, l->block_ref_to),
1694                                l->block_ref_to->logical_bytenr,
1695                                l->block_ref_to->dev_state->name,
1696                                l->block_ref_to->dev_bytenr,
1697                                l->block_ref_to->mirror_num);
1698                 }
1699
1700                 list_for_each_entry(l, &b_all->ref_from_list, node_ref_from) {
1701                         pr_info(" %c @%llu (%s/%llu/%d) is ref %u* from %c @%llu (%s/%llu/%d)\n",
1702                                btrfsic_get_block_type(state, b_all),
1703                                b_all->logical_bytenr, b_all->dev_state->name,
1704                                b_all->dev_bytenr, b_all->mirror_num,
1705                                l->ref_cnt,
1706                                btrfsic_get_block_type(state, l->block_ref_from),
1707                                l->block_ref_from->logical_bytenr,
1708                                l->block_ref_from->dev_state->name,
1709                                l->block_ref_from->dev_bytenr,
1710                                l->block_ref_from->mirror_num);
1711                 }
1712
1713                 pr_info("\n");
1714         }
1715 }
1716
1717 /*
1718  * Test whether the disk block contains a tree block (leaf or node)
1719  * (note that this test fails for the super block)
1720  */
1721 static int btrfsic_test_for_metadata(struct btrfsic_state *state,
1722                                      char **datav, unsigned int num_pages)
1723 {
1724         struct btrfs_fs_info *fs_info = state->fs_info;
1725         struct btrfs_header *h;
1726         u8 csum[BTRFS_CSUM_SIZE];
1727         u32 crc = ~(u32)0;
1728         unsigned int i;
1729
1730         if (num_pages * PAGE_SIZE < state->metablock_size)
1731                 return 1; /* not metadata */
1732         num_pages = state->metablock_size >> PAGE_SHIFT;
1733         h = (struct btrfs_header *)datav[0];
1734
1735         if (memcmp(h->fsid, fs_info->fsid, BTRFS_FSID_SIZE))
1736                 return 1;
1737
1738         for (i = 0; i < num_pages; i++) {
1739                 u8 *data = i ? datav[i] : (datav[i] + BTRFS_CSUM_SIZE);
1740                 size_t sublen = i ? PAGE_SIZE :
1741                                     (PAGE_SIZE - BTRFS_CSUM_SIZE);
1742
1743                 crc = btrfs_crc32c(crc, data, sublen);
1744         }
1745         btrfs_csum_final(crc, csum);
1746         if (memcmp(csum, h->csum, state->csum_size))
1747                 return 1;
1748
1749         return 0; /* is metadata */
1750 }
1751
1752 static void btrfsic_process_written_block(struct btrfsic_dev_state *dev_state,
1753                                           u64 dev_bytenr, char **mapped_datav,
1754                                           unsigned int num_pages,
1755                                           struct bio *bio, int *bio_is_patched,
1756                                           struct buffer_head *bh,
1757                                           int submit_bio_bh_rw)
1758 {
1759         int is_metadata;
1760         struct btrfsic_block *block;
1761         struct btrfsic_block_data_ctx block_ctx;
1762         int ret;
1763         struct btrfsic_state *state = dev_state->state;
1764         struct block_device *bdev = dev_state->bdev;
1765         unsigned int processed_len;
1766
1767         if (NULL != bio_is_patched)
1768                 *bio_is_patched = 0;
1769
1770 again:
1771         if (num_pages == 0)
1772                 return;
1773
1774         processed_len = 0;
1775         is_metadata = (0 == btrfsic_test_for_metadata(state, mapped_datav,
1776                                                       num_pages));
1777
1778         block = btrfsic_block_hashtable_lookup(bdev, dev_bytenr,
1779                                                &state->block_hashtable);
1780         if (NULL != block) {
1781                 u64 bytenr = 0;
1782                 struct btrfsic_block_link *l, *tmp;
1783
1784                 if (block->is_superblock) {
1785                         bytenr = btrfs_super_bytenr((struct btrfs_super_block *)
1786                                                     mapped_datav[0]);
1787                         if (num_pages * PAGE_SIZE <
1788                             BTRFS_SUPER_INFO_SIZE) {
1789                                 pr_info("btrfsic: cannot work with too short bios!\n");
1790                                 return;
1791                         }
1792                         is_metadata = 1;
1793                         BUG_ON(BTRFS_SUPER_INFO_SIZE & (PAGE_SIZE - 1));
1794                         processed_len = BTRFS_SUPER_INFO_SIZE;
1795                         if (state->print_mask &
1796                             BTRFSIC_PRINT_MASK_TREE_BEFORE_SB_WRITE) {
1797                                 pr_info("[before new superblock is written]:\n");
1798                                 btrfsic_dump_tree_sub(state, block, 0);
1799                         }
1800                 }
1801                 if (is_metadata) {
1802                         if (!block->is_superblock) {
1803                                 if (num_pages * PAGE_SIZE <
1804                                     state->metablock_size) {
1805                                         pr_info("btrfsic: cannot work with too short bios!\n");
1806                                         return;
1807                                 }
1808                                 processed_len = state->metablock_size;
1809                                 bytenr = btrfs_stack_header_bytenr(
1810                                                 (struct btrfs_header *)
1811                                                 mapped_datav[0]);
1812                                 btrfsic_cmp_log_and_dev_bytenr(state, bytenr,
1813                                                                dev_state,
1814                                                                dev_bytenr);
1815                         }
1816                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE) {
1817                                 if (block->logical_bytenr != bytenr &&
1818                                     !(!block->is_metadata &&
1819                                       block->logical_bytenr == 0))
1820                                         pr_info("Written block @%llu (%s/%llu/%d) found in hash table, %c, bytenr mismatch (!= stored %llu).\n",
1821                                                bytenr, dev_state->name,
1822                                                dev_bytenr,
1823                                                block->mirror_num,
1824                                                btrfsic_get_block_type(state,
1825                                                                       block),
1826                                                block->logical_bytenr);
1827                                 else
1828                                         pr_info("Written block @%llu (%s/%llu/%d) found in hash table, %c.\n",
1829                                                bytenr, dev_state->name,
1830                                                dev_bytenr, block->mirror_num,
1831                                                btrfsic_get_block_type(state,
1832                                                                       block));
1833                         }
1834                         block->logical_bytenr = bytenr;
1835                 } else {
1836                         if (num_pages * PAGE_SIZE <
1837                             state->datablock_size) {
1838                                 pr_info("btrfsic: cannot work with too short bios!\n");
1839                                 return;
1840                         }
1841                         processed_len = state->datablock_size;
1842                         bytenr = block->logical_bytenr;
1843                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1844                                 pr_info("Written block @%llu (%s/%llu/%d) found in hash table, %c.\n",
1845                                        bytenr, dev_state->name, dev_bytenr,
1846                                        block->mirror_num,
1847                                        btrfsic_get_block_type(state, block));
1848                 }
1849
1850                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1851                         pr_info("ref_to_list: %cE, ref_from_list: %cE\n",
1852                                list_empty(&block->ref_to_list) ? ' ' : '!',
1853                                list_empty(&block->ref_from_list) ? ' ' : '!');
1854                 if (btrfsic_is_block_ref_by_superblock(state, block, 0)) {
1855                         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",
1856                                btrfsic_get_block_type(state, block), bytenr,
1857                                dev_state->name, dev_bytenr, block->mirror_num,
1858                                block->generation,
1859                                btrfs_disk_key_objectid(&block->disk_key),
1860                                block->disk_key.type,
1861                                btrfs_disk_key_offset(&block->disk_key),
1862                                btrfs_stack_header_generation(
1863                                        (struct btrfs_header *) mapped_datav[0]),
1864                                state->max_superblock_generation);
1865                         btrfsic_dump_tree(state);
1866                 }
1867
1868                 if (!block->is_iodone && !block->never_written) {
1869                         pr_info("btrfs: attempt to overwrite %c-block @%llu (%s/%llu/%d), oldgen=%llu, newgen=%llu, which is not yet iodone!\n",
1870                                btrfsic_get_block_type(state, block), bytenr,
1871                                dev_state->name, dev_bytenr, block->mirror_num,
1872                                block->generation,
1873                                btrfs_stack_header_generation(
1874                                        (struct btrfs_header *)
1875                                        mapped_datav[0]));
1876                         /* it would not be safe to go on */
1877                         btrfsic_dump_tree(state);
1878                         goto continue_loop;
1879                 }
1880
1881                 /*
1882                  * Clear all references of this block. Do not free
1883                  * the block itself even if is not referenced anymore
1884                  * because it still carries valuable information
1885                  * like whether it was ever written and IO completed.
1886                  */
1887                 list_for_each_entry_safe(l, tmp, &block->ref_to_list,
1888                                          node_ref_to) {
1889                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1890                                 btrfsic_print_rem_link(state, l);
1891                         l->ref_cnt--;
1892                         if (0 == l->ref_cnt) {
1893                                 list_del(&l->node_ref_to);
1894                                 list_del(&l->node_ref_from);
1895                                 btrfsic_block_link_hashtable_remove(l);
1896                                 btrfsic_block_link_free(l);
1897                         }
1898                 }
1899
1900                 block_ctx.dev = dev_state;
1901                 block_ctx.dev_bytenr = dev_bytenr;
1902                 block_ctx.start = bytenr;
1903                 block_ctx.len = processed_len;
1904                 block_ctx.pagev = NULL;
1905                 block_ctx.mem_to_free = NULL;
1906                 block_ctx.datav = mapped_datav;
1907
1908                 if (is_metadata || state->include_extent_data) {
1909                         block->never_written = 0;
1910                         block->iodone_w_error = 0;
1911                         if (NULL != bio) {
1912                                 block->is_iodone = 0;
1913                                 BUG_ON(NULL == bio_is_patched);
1914                                 if (!*bio_is_patched) {
1915                                         block->orig_bio_bh_private =
1916                                             bio->bi_private;
1917                                         block->orig_bio_bh_end_io.bio =
1918                                             bio->bi_end_io;
1919                                         block->next_in_same_bio = NULL;
1920                                         bio->bi_private = block;
1921                                         bio->bi_end_io = btrfsic_bio_end_io;
1922                                         *bio_is_patched = 1;
1923                                 } else {
1924                                         struct btrfsic_block *chained_block =
1925                                             (struct btrfsic_block *)
1926                                             bio->bi_private;
1927
1928                                         BUG_ON(NULL == chained_block);
1929                                         block->orig_bio_bh_private =
1930                                             chained_block->orig_bio_bh_private;
1931                                         block->orig_bio_bh_end_io.bio =
1932                                             chained_block->orig_bio_bh_end_io.
1933                                             bio;
1934                                         block->next_in_same_bio = chained_block;
1935                                         bio->bi_private = block;
1936                                 }
1937                         } else if (NULL != bh) {
1938                                 block->is_iodone = 0;
1939                                 block->orig_bio_bh_private = bh->b_private;
1940                                 block->orig_bio_bh_end_io.bh = bh->b_end_io;
1941                                 block->next_in_same_bio = NULL;
1942                                 bh->b_private = block;
1943                                 bh->b_end_io = btrfsic_bh_end_io;
1944                         } else {
1945                                 block->is_iodone = 1;
1946                                 block->orig_bio_bh_private = NULL;
1947                                 block->orig_bio_bh_end_io.bio = NULL;
1948                                 block->next_in_same_bio = NULL;
1949                         }
1950                 }
1951
1952                 block->flush_gen = dev_state->last_flush_gen + 1;
1953                 block->submit_bio_bh_rw = submit_bio_bh_rw;
1954                 if (is_metadata) {
1955                         block->logical_bytenr = bytenr;
1956                         block->is_metadata = 1;
1957                         if (block->is_superblock) {
1958                                 BUG_ON(PAGE_SIZE !=
1959                                        BTRFS_SUPER_INFO_SIZE);
1960                                 ret = btrfsic_process_written_superblock(
1961                                                 state,
1962                                                 block,
1963                                                 (struct btrfs_super_block *)
1964                                                 mapped_datav[0]);
1965                                 if (state->print_mask &
1966                                     BTRFSIC_PRINT_MASK_TREE_AFTER_SB_WRITE) {
1967                                         pr_info("[after new superblock is written]:\n");
1968                                         btrfsic_dump_tree_sub(state, block, 0);
1969                                 }
1970                         } else {
1971                                 block->mirror_num = 0;  /* unknown */
1972                                 ret = btrfsic_process_metablock(
1973                                                 state,
1974                                                 block,
1975                                                 &block_ctx,
1976                                                 0, 0);
1977                         }
1978                         if (ret)
1979                                 pr_info("btrfsic: btrfsic_process_metablock(root @%llu) failed!\n",
1980                                        dev_bytenr);
1981                 } else {
1982                         block->is_metadata = 0;
1983                         block->mirror_num = 0;  /* unknown */
1984                         block->generation = BTRFSIC_GENERATION_UNKNOWN;
1985                         if (!state->include_extent_data
1986                             && list_empty(&block->ref_from_list)) {
1987                                 /*
1988                                  * disk block is overwritten with extent
1989                                  * data (not meta data) and we are configured
1990                                  * to not include extent data: take the
1991                                  * chance and free the block's memory
1992                                  */
1993                                 btrfsic_block_hashtable_remove(block);
1994                                 list_del(&block->all_blocks_node);
1995                                 btrfsic_block_free(block);
1996                         }
1997                 }
1998                 btrfsic_release_block_ctx(&block_ctx);
1999         } else {
2000                 /* block has not been found in hash table */
2001                 u64 bytenr;
2002
2003                 if (!is_metadata) {
2004                         processed_len = state->datablock_size;
2005                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2006                                 pr_info("Written block (%s/%llu/?) !found in hash table, D.\n",
2007                                        dev_state->name, dev_bytenr);
2008                         if (!state->include_extent_data) {
2009                                 /* ignore that written D block */
2010                                 goto continue_loop;
2011                         }
2012
2013                         /* this is getting ugly for the
2014                          * include_extent_data case... */
2015                         bytenr = 0;     /* unknown */
2016                 } else {
2017                         processed_len = state->metablock_size;
2018                         bytenr = btrfs_stack_header_bytenr(
2019                                         (struct btrfs_header *)
2020                                         mapped_datav[0]);
2021                         btrfsic_cmp_log_and_dev_bytenr(state, bytenr, dev_state,
2022                                                        dev_bytenr);
2023                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2024                                 pr_info("Written block @%llu (%s/%llu/?) !found in hash table, M.\n",
2025                                        bytenr, dev_state->name, dev_bytenr);
2026                 }
2027
2028                 block_ctx.dev = dev_state;
2029                 block_ctx.dev_bytenr = dev_bytenr;
2030                 block_ctx.start = bytenr;
2031                 block_ctx.len = processed_len;
2032                 block_ctx.pagev = NULL;
2033                 block_ctx.mem_to_free = NULL;
2034                 block_ctx.datav = mapped_datav;
2035
2036                 block = btrfsic_block_alloc();
2037                 if (NULL == block) {
2038                         pr_info("btrfsic: error, kmalloc failed!\n");
2039                         btrfsic_release_block_ctx(&block_ctx);
2040                         goto continue_loop;
2041                 }
2042                 block->dev_state = dev_state;
2043                 block->dev_bytenr = dev_bytenr;
2044                 block->logical_bytenr = bytenr;
2045                 block->is_metadata = is_metadata;
2046                 block->never_written = 0;
2047                 block->iodone_w_error = 0;
2048                 block->mirror_num = 0;  /* unknown */
2049                 block->flush_gen = dev_state->last_flush_gen + 1;
2050                 block->submit_bio_bh_rw = submit_bio_bh_rw;
2051                 if (NULL != bio) {
2052                         block->is_iodone = 0;
2053                         BUG_ON(NULL == bio_is_patched);
2054                         if (!*bio_is_patched) {
2055                                 block->orig_bio_bh_private = bio->bi_private;
2056                                 block->orig_bio_bh_end_io.bio = bio->bi_end_io;
2057                                 block->next_in_same_bio = NULL;
2058                                 bio->bi_private = block;
2059                                 bio->bi_end_io = btrfsic_bio_end_io;
2060                                 *bio_is_patched = 1;
2061                         } else {
2062                                 struct btrfsic_block *chained_block =
2063                                     (struct btrfsic_block *)
2064                                     bio->bi_private;
2065
2066                                 BUG_ON(NULL == chained_block);
2067                                 block->orig_bio_bh_private =
2068                                     chained_block->orig_bio_bh_private;
2069                                 block->orig_bio_bh_end_io.bio =
2070                                     chained_block->orig_bio_bh_end_io.bio;
2071                                 block->next_in_same_bio = chained_block;
2072                                 bio->bi_private = block;
2073                         }
2074                 } else if (NULL != bh) {
2075                         block->is_iodone = 0;
2076                         block->orig_bio_bh_private = bh->b_private;
2077                         block->orig_bio_bh_end_io.bh = bh->b_end_io;
2078                         block->next_in_same_bio = NULL;
2079                         bh->b_private = block;
2080                         bh->b_end_io = btrfsic_bh_end_io;
2081                 } else {
2082                         block->is_iodone = 1;
2083                         block->orig_bio_bh_private = NULL;
2084                         block->orig_bio_bh_end_io.bio = NULL;
2085                         block->next_in_same_bio = NULL;
2086                 }
2087                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2088                         pr_info("New written %c-block @%llu (%s/%llu/%d)\n",
2089                                is_metadata ? 'M' : 'D',
2090                                block->logical_bytenr, block->dev_state->name,
2091                                block->dev_bytenr, block->mirror_num);
2092                 list_add(&block->all_blocks_node, &state->all_blocks_list);
2093                 btrfsic_block_hashtable_add(block, &state->block_hashtable);
2094
2095                 if (is_metadata) {
2096                         ret = btrfsic_process_metablock(state, block,
2097                                                         &block_ctx, 0, 0);
2098                         if (ret)
2099                                 pr_info("btrfsic: process_metablock(root @%llu) failed!\n",
2100                                        dev_bytenr);
2101                 }
2102                 btrfsic_release_block_ctx(&block_ctx);
2103         }
2104
2105 continue_loop:
2106         BUG_ON(!processed_len);
2107         dev_bytenr += processed_len;
2108         mapped_datav += processed_len >> PAGE_SHIFT;
2109         num_pages -= processed_len >> PAGE_SHIFT;
2110         goto again;
2111 }
2112
2113 static void btrfsic_bio_end_io(struct bio *bp)
2114 {
2115         struct btrfsic_block *block = (struct btrfsic_block *)bp->bi_private;
2116         int iodone_w_error;
2117
2118         /* mutex is not held! This is not save if IO is not yet completed
2119          * on umount */
2120         iodone_w_error = 0;
2121         if (bp->bi_status)
2122                 iodone_w_error = 1;
2123
2124         BUG_ON(NULL == block);
2125         bp->bi_private = block->orig_bio_bh_private;
2126         bp->bi_end_io = block->orig_bio_bh_end_io.bio;
2127
2128         do {
2129                 struct btrfsic_block *next_block;
2130                 struct btrfsic_dev_state *const dev_state = block->dev_state;
2131
2132                 if ((dev_state->state->print_mask &
2133                      BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2134                         pr_info("bio_end_io(err=%d) for %c @%llu (%s/%llu/%d)\n",
2135                                bp->bi_status,
2136                                btrfsic_get_block_type(dev_state->state, block),
2137                                block->logical_bytenr, dev_state->name,
2138                                block->dev_bytenr, block->mirror_num);
2139                 next_block = block->next_in_same_bio;
2140                 block->iodone_w_error = iodone_w_error;
2141                 if (block->submit_bio_bh_rw & REQ_PREFLUSH) {
2142                         dev_state->last_flush_gen++;
2143                         if ((dev_state->state->print_mask &
2144                              BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2145                                 pr_info("bio_end_io() new %s flush_gen=%llu\n",
2146                                        dev_state->name,
2147                                        dev_state->last_flush_gen);
2148                 }
2149                 if (block->submit_bio_bh_rw & REQ_FUA)
2150                         block->flush_gen = 0; /* FUA completed means block is
2151                                                * on disk */
2152                 block->is_iodone = 1; /* for FLUSH, this releases the block */
2153                 block = next_block;
2154         } while (NULL != block);
2155
2156         bp->bi_end_io(bp);
2157 }
2158
2159 static void btrfsic_bh_end_io(struct buffer_head *bh, int uptodate)
2160 {
2161         struct btrfsic_block *block = (struct btrfsic_block *)bh->b_private;
2162         int iodone_w_error = !uptodate;
2163         struct btrfsic_dev_state *dev_state;
2164
2165         BUG_ON(NULL == block);
2166         dev_state = block->dev_state;
2167         if ((dev_state->state->print_mask & BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2168                 pr_info("bh_end_io(error=%d) for %c @%llu (%s/%llu/%d)\n",
2169                        iodone_w_error,
2170                        btrfsic_get_block_type(dev_state->state, block),
2171                        block->logical_bytenr, block->dev_state->name,
2172                        block->dev_bytenr, block->mirror_num);
2173
2174         block->iodone_w_error = iodone_w_error;
2175         if (block->submit_bio_bh_rw & REQ_PREFLUSH) {
2176                 dev_state->last_flush_gen++;
2177                 if ((dev_state->state->print_mask &
2178                      BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2179                         pr_info("bh_end_io() new %s flush_gen=%llu\n",
2180                                dev_state->name, dev_state->last_flush_gen);
2181         }
2182         if (block->submit_bio_bh_rw & REQ_FUA)
2183                 block->flush_gen = 0; /* FUA completed means block is on disk */
2184
2185         bh->b_private = block->orig_bio_bh_private;
2186         bh->b_end_io = block->orig_bio_bh_end_io.bh;
2187         block->is_iodone = 1; /* for FLUSH, this releases the block */
2188         bh->b_end_io(bh, uptodate);
2189 }
2190
2191 static int btrfsic_process_written_superblock(
2192                 struct btrfsic_state *state,
2193                 struct btrfsic_block *const superblock,
2194                 struct btrfs_super_block *const super_hdr)
2195 {
2196         struct btrfs_fs_info *fs_info = state->fs_info;
2197         int pass;
2198
2199         superblock->generation = btrfs_super_generation(super_hdr);
2200         if (!(superblock->generation > state->max_superblock_generation ||
2201               0 == state->max_superblock_generation)) {
2202                 if (state->print_mask & BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE)
2203                         pr_info("btrfsic: superblock @%llu (%s/%llu/%d) with old gen %llu <= %llu\n",
2204                                superblock->logical_bytenr,
2205                                superblock->dev_state->name,
2206                                superblock->dev_bytenr, superblock->mirror_num,
2207                                btrfs_super_generation(super_hdr),
2208                                state->max_superblock_generation);
2209         } else {
2210                 if (state->print_mask & BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE)
2211                         pr_info("btrfsic: got new superblock @%llu (%s/%llu/%d) with new gen %llu > %llu\n",
2212                                superblock->logical_bytenr,
2213                                superblock->dev_state->name,
2214                                superblock->dev_bytenr, superblock->mirror_num,
2215                                btrfs_super_generation(super_hdr),
2216                                state->max_superblock_generation);
2217
2218                 state->max_superblock_generation =
2219                     btrfs_super_generation(super_hdr);
2220                 state->latest_superblock = superblock;
2221         }
2222
2223         for (pass = 0; pass < 3; pass++) {
2224                 int ret;
2225                 u64 next_bytenr;
2226                 struct btrfsic_block *next_block;
2227                 struct btrfsic_block_data_ctx tmp_next_block_ctx;
2228                 struct btrfsic_block_link *l;
2229                 int num_copies;
2230                 int mirror_num;
2231                 const char *additional_string = NULL;
2232                 struct btrfs_disk_key tmp_disk_key = {0};
2233
2234                 btrfs_set_disk_key_objectid(&tmp_disk_key,
2235                                             BTRFS_ROOT_ITEM_KEY);
2236                 btrfs_set_disk_key_objectid(&tmp_disk_key, 0);
2237
2238                 switch (pass) {
2239                 case 0:
2240                         btrfs_set_disk_key_objectid(&tmp_disk_key,
2241                                                     BTRFS_ROOT_TREE_OBJECTID);
2242                         additional_string = "root ";
2243                         next_bytenr = btrfs_super_root(super_hdr);
2244                         if (state->print_mask &
2245                             BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
2246                                 pr_info("root@%llu\n", next_bytenr);
2247                         break;
2248                 case 1:
2249                         btrfs_set_disk_key_objectid(&tmp_disk_key,
2250                                                     BTRFS_CHUNK_TREE_OBJECTID);
2251                         additional_string = "chunk ";
2252                         next_bytenr = btrfs_super_chunk_root(super_hdr);
2253                         if (state->print_mask &
2254                             BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
2255                                 pr_info("chunk@%llu\n", next_bytenr);
2256                         break;
2257                 case 2:
2258                         btrfs_set_disk_key_objectid(&tmp_disk_key,
2259                                                     BTRFS_TREE_LOG_OBJECTID);
2260                         additional_string = "log ";
2261                         next_bytenr = btrfs_super_log_root(super_hdr);
2262                         if (0 == next_bytenr)
2263                                 continue;
2264                         if (state->print_mask &
2265                             BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
2266                                 pr_info("log@%llu\n", next_bytenr);
2267                         break;
2268                 }
2269
2270                 num_copies = btrfs_num_copies(fs_info, next_bytenr,
2271                                               BTRFS_SUPER_INFO_SIZE);
2272                 if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
2273                         pr_info("num_copies(log_bytenr=%llu) = %d\n",
2274                                next_bytenr, num_copies);
2275                 for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
2276                         int was_created;
2277
2278                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2279                                 pr_info("btrfsic_process_written_superblock(mirror_num=%d)\n", mirror_num);
2280                         ret = btrfsic_map_block(state, next_bytenr,
2281                                                 BTRFS_SUPER_INFO_SIZE,
2282                                                 &tmp_next_block_ctx,
2283                                                 mirror_num);
2284                         if (ret) {
2285                                 pr_info("btrfsic: btrfsic_map_block(@%llu, mirror=%d) failed!\n",
2286                                        next_bytenr, mirror_num);
2287                                 return -1;
2288                         }
2289
2290                         next_block = btrfsic_block_lookup_or_add(
2291                                         state,
2292                                         &tmp_next_block_ctx,
2293                                         additional_string,
2294                                         1, 0, 1,
2295                                         mirror_num,
2296                                         &was_created);
2297                         if (NULL == next_block) {
2298                                 pr_info("btrfsic: error, kmalloc failed!\n");
2299                                 btrfsic_release_block_ctx(&tmp_next_block_ctx);
2300                                 return -1;
2301                         }
2302
2303                         next_block->disk_key = tmp_disk_key;
2304                         if (was_created)
2305                                 next_block->generation =
2306                                     BTRFSIC_GENERATION_UNKNOWN;
2307                         l = btrfsic_block_link_lookup_or_add(
2308                                         state,
2309                                         &tmp_next_block_ctx,
2310                                         next_block,
2311                                         superblock,
2312                                         BTRFSIC_GENERATION_UNKNOWN);
2313                         btrfsic_release_block_ctx(&tmp_next_block_ctx);
2314                         if (NULL == l)
2315                                 return -1;
2316                 }
2317         }
2318
2319         if (WARN_ON(-1 == btrfsic_check_all_ref_blocks(state, superblock, 0)))
2320                 btrfsic_dump_tree(state);
2321
2322         return 0;
2323 }
2324
2325 static int btrfsic_check_all_ref_blocks(struct btrfsic_state *state,
2326                                         struct btrfsic_block *const block,
2327                                         int recursion_level)
2328 {
2329         const struct btrfsic_block_link *l;
2330         int ret = 0;
2331
2332         if (recursion_level >= 3 + BTRFS_MAX_LEVEL) {
2333                 /*
2334                  * Note that this situation can happen and does not
2335                  * indicate an error in regular cases. It happens
2336                  * when disk blocks are freed and later reused.
2337                  * The check-integrity module is not aware of any
2338                  * block free operations, it just recognizes block
2339                  * write operations. Therefore it keeps the linkage
2340                  * information for a block until a block is
2341                  * rewritten. This can temporarily cause incorrect
2342                  * and even circular linkage informations. This
2343                  * causes no harm unless such blocks are referenced
2344                  * by the most recent super block.
2345                  */
2346                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2347                         pr_info("btrfsic: abort cyclic linkage (case 1).\n");
2348
2349                 return ret;
2350         }
2351
2352         /*
2353          * This algorithm is recursive because the amount of used stack
2354          * space is very small and the max recursion depth is limited.
2355          */
2356         list_for_each_entry(l, &block->ref_to_list, node_ref_to) {
2357                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2358                         pr_info("rl=%d, %c @%llu (%s/%llu/%d) %u* refers to %c @%llu (%s/%llu/%d)\n",
2359                                recursion_level,
2360                                btrfsic_get_block_type(state, block),
2361                                block->logical_bytenr, block->dev_state->name,
2362                                block->dev_bytenr, block->mirror_num,
2363                                l->ref_cnt,
2364                                btrfsic_get_block_type(state, l->block_ref_to),
2365                                l->block_ref_to->logical_bytenr,
2366                                l->block_ref_to->dev_state->name,
2367                                l->block_ref_to->dev_bytenr,
2368                                l->block_ref_to->mirror_num);
2369                 if (l->block_ref_to->never_written) {
2370                         pr_info("btrfs: attempt to write superblock which references block %c @%llu (%s/%llu/%d) which is never written!\n",
2371                                btrfsic_get_block_type(state, l->block_ref_to),
2372                                l->block_ref_to->logical_bytenr,
2373                                l->block_ref_to->dev_state->name,
2374                                l->block_ref_to->dev_bytenr,
2375                                l->block_ref_to->mirror_num);
2376                         ret = -1;
2377                 } else if (!l->block_ref_to->is_iodone) {
2378                         pr_info("btrfs: attempt to write superblock which references block %c @%llu (%s/%llu/%d) which is not yet iodone!\n",
2379                                btrfsic_get_block_type(state, l->block_ref_to),
2380                                l->block_ref_to->logical_bytenr,
2381                                l->block_ref_to->dev_state->name,
2382                                l->block_ref_to->dev_bytenr,
2383                                l->block_ref_to->mirror_num);
2384                         ret = -1;
2385                 } else if (l->block_ref_to->iodone_w_error) {
2386                         pr_info("btrfs: attempt to write superblock which references block %c @%llu (%s/%llu/%d) which has write error!\n",
2387                                btrfsic_get_block_type(state, l->block_ref_to),
2388                                l->block_ref_to->logical_bytenr,
2389                                l->block_ref_to->dev_state->name,
2390                                l->block_ref_to->dev_bytenr,
2391                                l->block_ref_to->mirror_num);
2392                         ret = -1;
2393                 } else if (l->parent_generation !=
2394                            l->block_ref_to->generation &&
2395                            BTRFSIC_GENERATION_UNKNOWN !=
2396                            l->parent_generation &&
2397                            BTRFSIC_GENERATION_UNKNOWN !=
2398                            l->block_ref_to->generation) {
2399                         pr_info("btrfs: attempt to write superblock which references block %c @%llu (%s/%llu/%d) with generation %llu != parent generation %llu!\n",
2400                                btrfsic_get_block_type(state, l->block_ref_to),
2401                                l->block_ref_to->logical_bytenr,
2402                                l->block_ref_to->dev_state->name,
2403                                l->block_ref_to->dev_bytenr,
2404                                l->block_ref_to->mirror_num,
2405                                l->block_ref_to->generation,
2406                                l->parent_generation);
2407                         ret = -1;
2408                 } else if (l->block_ref_to->flush_gen >
2409                            l->block_ref_to->dev_state->last_flush_gen) {
2410                         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",
2411                                btrfsic_get_block_type(state, l->block_ref_to),
2412                                l->block_ref_to->logical_bytenr,
2413                                l->block_ref_to->dev_state->name,
2414                                l->block_ref_to->dev_bytenr,
2415                                l->block_ref_to->mirror_num, block->flush_gen,
2416                                l->block_ref_to->dev_state->last_flush_gen);
2417                         ret = -1;
2418                 } else if (-1 == btrfsic_check_all_ref_blocks(state,
2419                                                               l->block_ref_to,
2420                                                               recursion_level +
2421                                                               1)) {
2422                         ret = -1;
2423                 }
2424         }
2425
2426         return ret;
2427 }
2428
2429 static int btrfsic_is_block_ref_by_superblock(
2430                 const struct btrfsic_state *state,
2431                 const struct btrfsic_block *block,
2432                 int recursion_level)
2433 {
2434         const struct btrfsic_block_link *l;
2435
2436         if (recursion_level >= 3 + BTRFS_MAX_LEVEL) {
2437                 /* refer to comment at "abort cyclic linkage (case 1)" */
2438                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2439                         pr_info("btrfsic: abort cyclic linkage (case 2).\n");
2440
2441                 return 0;
2442         }
2443
2444         /*
2445          * This algorithm is recursive because the amount of used stack space
2446          * is very small and the max recursion depth is limited.
2447          */
2448         list_for_each_entry(l, &block->ref_from_list, node_ref_from) {
2449                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2450                         pr_info("rl=%d, %c @%llu (%s/%llu/%d) is ref %u* from %c @%llu (%s/%llu/%d)\n",
2451                                recursion_level,
2452                                btrfsic_get_block_type(state, block),
2453                                block->logical_bytenr, block->dev_state->name,
2454                                block->dev_bytenr, block->mirror_num,
2455                                l->ref_cnt,
2456                                btrfsic_get_block_type(state, l->block_ref_from),
2457                                l->block_ref_from->logical_bytenr,
2458                                l->block_ref_from->dev_state->name,
2459                                l->block_ref_from->dev_bytenr,
2460                                l->block_ref_from->mirror_num);
2461                 if (l->block_ref_from->is_superblock &&
2462                     state->latest_superblock->dev_bytenr ==
2463                     l->block_ref_from->dev_bytenr &&
2464                     state->latest_superblock->dev_state->bdev ==
2465                     l->block_ref_from->dev_state->bdev)
2466                         return 1;
2467                 else if (btrfsic_is_block_ref_by_superblock(state,
2468                                                             l->block_ref_from,
2469                                                             recursion_level +
2470                                                             1))
2471                         return 1;
2472         }
2473
2474         return 0;
2475 }
2476
2477 static void btrfsic_print_add_link(const struct btrfsic_state *state,
2478                                    const struct btrfsic_block_link *l)
2479 {
2480         pr_info("Add %u* link from %c @%llu (%s/%llu/%d) to %c @%llu (%s/%llu/%d).\n",
2481                l->ref_cnt,
2482                btrfsic_get_block_type(state, l->block_ref_from),
2483                l->block_ref_from->logical_bytenr,
2484                l->block_ref_from->dev_state->name,
2485                l->block_ref_from->dev_bytenr, l->block_ref_from->mirror_num,
2486                btrfsic_get_block_type(state, l->block_ref_to),
2487                l->block_ref_to->logical_bytenr,
2488                l->block_ref_to->dev_state->name, l->block_ref_to->dev_bytenr,
2489                l->block_ref_to->mirror_num);
2490 }
2491
2492 static void btrfsic_print_rem_link(const struct btrfsic_state *state,
2493                                    const struct btrfsic_block_link *l)
2494 {
2495         pr_info("Rem %u* link from %c @%llu (%s/%llu/%d) to %c @%llu (%s/%llu/%d).\n",
2496                l->ref_cnt,
2497                btrfsic_get_block_type(state, l->block_ref_from),
2498                l->block_ref_from->logical_bytenr,
2499                l->block_ref_from->dev_state->name,
2500                l->block_ref_from->dev_bytenr, l->block_ref_from->mirror_num,
2501                btrfsic_get_block_type(state, l->block_ref_to),
2502                l->block_ref_to->logical_bytenr,
2503                l->block_ref_to->dev_state->name, l->block_ref_to->dev_bytenr,
2504                l->block_ref_to->mirror_num);
2505 }
2506
2507 static char btrfsic_get_block_type(const struct btrfsic_state *state,
2508                                    const struct btrfsic_block *block)
2509 {
2510         if (block->is_superblock &&
2511             state->latest_superblock->dev_bytenr == block->dev_bytenr &&
2512             state->latest_superblock->dev_state->bdev == block->dev_state->bdev)
2513                 return 'S';
2514         else if (block->is_superblock)
2515                 return 's';
2516         else if (block->is_metadata)
2517                 return 'M';
2518         else
2519                 return 'D';
2520 }
2521
2522 static void btrfsic_dump_tree(const struct btrfsic_state *state)
2523 {
2524         btrfsic_dump_tree_sub(state, state->latest_superblock, 0);
2525 }
2526
2527 static void btrfsic_dump_tree_sub(const struct btrfsic_state *state,
2528                                   const struct btrfsic_block *block,
2529                                   int indent_level)
2530 {
2531         const struct btrfsic_block_link *l;
2532         int indent_add;
2533         static char buf[80];
2534         int cursor_position;
2535
2536         /*
2537          * Should better fill an on-stack buffer with a complete line and
2538          * dump it at once when it is time to print a newline character.
2539          */
2540
2541         /*
2542          * This algorithm is recursive because the amount of used stack space
2543          * is very small and the max recursion depth is limited.
2544          */
2545         indent_add = sprintf(buf, "%c-%llu(%s/%llu/%u)",
2546                              btrfsic_get_block_type(state, block),
2547                              block->logical_bytenr, block->dev_state->name,
2548                              block->dev_bytenr, block->mirror_num);
2549         if (indent_level + indent_add > BTRFSIC_TREE_DUMP_MAX_INDENT_LEVEL) {
2550                 printk("[...]\n");
2551                 return;
2552         }
2553         printk(buf);
2554         indent_level += indent_add;
2555         if (list_empty(&block->ref_to_list)) {
2556                 printk("\n");
2557                 return;
2558         }
2559         if (block->mirror_num > 1 &&
2560             !(state->print_mask & BTRFSIC_PRINT_MASK_TREE_WITH_ALL_MIRRORS)) {
2561                 printk(" [...]\n");
2562                 return;
2563         }
2564
2565         cursor_position = indent_level;
2566         list_for_each_entry(l, &block->ref_to_list, node_ref_to) {
2567                 while (cursor_position < indent_level) {
2568                         printk(" ");
2569                         cursor_position++;
2570                 }
2571                 if (l->ref_cnt > 1)
2572                         indent_add = sprintf(buf, " %d*--> ", l->ref_cnt);
2573                 else
2574                         indent_add = sprintf(buf, " --> ");
2575                 if (indent_level + indent_add >
2576                     BTRFSIC_TREE_DUMP_MAX_INDENT_LEVEL) {
2577                         printk("[...]\n");
2578                         cursor_position = 0;
2579                         continue;
2580                 }
2581
2582                 printk(buf);
2583
2584                 btrfsic_dump_tree_sub(state, l->block_ref_to,
2585                                       indent_level + indent_add);
2586                 cursor_position = 0;
2587         }
2588 }
2589
2590 static struct btrfsic_block_link *btrfsic_block_link_lookup_or_add(
2591                 struct btrfsic_state *state,
2592                 struct btrfsic_block_data_ctx *next_block_ctx,
2593                 struct btrfsic_block *next_block,
2594                 struct btrfsic_block *from_block,
2595                 u64 parent_generation)
2596 {
2597         struct btrfsic_block_link *l;
2598
2599         l = btrfsic_block_link_hashtable_lookup(next_block_ctx->dev->bdev,
2600                                                 next_block_ctx->dev_bytenr,
2601                                                 from_block->dev_state->bdev,
2602                                                 from_block->dev_bytenr,
2603                                                 &state->block_link_hashtable);
2604         if (NULL == l) {
2605                 l = btrfsic_block_link_alloc();
2606                 if (NULL == l) {
2607                         pr_info("btrfsic: error, kmalloc failed!\n");
2608                         return NULL;
2609                 }
2610
2611                 l->block_ref_to = next_block;
2612                 l->block_ref_from = from_block;
2613                 l->ref_cnt = 1;
2614                 l->parent_generation = parent_generation;
2615
2616                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2617                         btrfsic_print_add_link(state, l);
2618
2619                 list_add(&l->node_ref_to, &from_block->ref_to_list);
2620                 list_add(&l->node_ref_from, &next_block->ref_from_list);
2621
2622                 btrfsic_block_link_hashtable_add(l,
2623                                                  &state->block_link_hashtable);
2624         } else {
2625                 l->ref_cnt++;
2626                 l->parent_generation = parent_generation;
2627                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2628                         btrfsic_print_add_link(state, l);
2629         }
2630
2631         return l;
2632 }
2633
2634 static struct btrfsic_block *btrfsic_block_lookup_or_add(
2635                 struct btrfsic_state *state,
2636                 struct btrfsic_block_data_ctx *block_ctx,
2637                 const char *additional_string,
2638                 int is_metadata,
2639                 int is_iodone,
2640                 int never_written,
2641                 int mirror_num,
2642                 int *was_created)
2643 {
2644         struct btrfsic_block *block;
2645
2646         block = btrfsic_block_hashtable_lookup(block_ctx->dev->bdev,
2647                                                block_ctx->dev_bytenr,
2648                                                &state->block_hashtable);
2649         if (NULL == block) {
2650                 struct btrfsic_dev_state *dev_state;
2651
2652                 block = btrfsic_block_alloc();
2653                 if (NULL == block) {
2654                         pr_info("btrfsic: error, kmalloc failed!\n");
2655                         return NULL;
2656                 }
2657                 dev_state = btrfsic_dev_state_lookup(block_ctx->dev->bdev);
2658                 if (NULL == dev_state) {
2659                         pr_info("btrfsic: error, lookup dev_state failed!\n");
2660                         btrfsic_block_free(block);
2661                         return NULL;
2662                 }
2663                 block->dev_state = dev_state;
2664                 block->dev_bytenr = block_ctx->dev_bytenr;
2665                 block->logical_bytenr = block_ctx->start;
2666                 block->is_metadata = is_metadata;
2667                 block->is_iodone = is_iodone;
2668                 block->never_written = never_written;
2669                 block->mirror_num = mirror_num;
2670                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2671                         pr_info("New %s%c-block @%llu (%s/%llu/%d)\n",
2672                                additional_string,
2673                                btrfsic_get_block_type(state, block),
2674                                block->logical_bytenr, dev_state->name,
2675                                block->dev_bytenr, mirror_num);
2676                 list_add(&block->all_blocks_node, &state->all_blocks_list);
2677                 btrfsic_block_hashtable_add(block, &state->block_hashtable);
2678                 if (NULL != was_created)
2679                         *was_created = 1;
2680         } else {
2681                 if (NULL != was_created)
2682                         *was_created = 0;
2683         }
2684
2685         return block;
2686 }
2687
2688 static void btrfsic_cmp_log_and_dev_bytenr(struct btrfsic_state *state,
2689                                            u64 bytenr,
2690                                            struct btrfsic_dev_state *dev_state,
2691                                            u64 dev_bytenr)
2692 {
2693         struct btrfs_fs_info *fs_info = state->fs_info;
2694         struct btrfsic_block_data_ctx block_ctx;
2695         int num_copies;
2696         int mirror_num;
2697         int match = 0;
2698         int ret;
2699
2700         num_copies = btrfs_num_copies(fs_info, bytenr, state->metablock_size);
2701
2702         for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
2703                 ret = btrfsic_map_block(state, bytenr, state->metablock_size,
2704                                         &block_ctx, mirror_num);
2705                 if (ret) {
2706                         pr_info("btrfsic: btrfsic_map_block(logical @%llu, mirror %d) failed!\n",
2707                                bytenr, mirror_num);
2708                         continue;
2709                 }
2710
2711                 if (dev_state->bdev == block_ctx.dev->bdev &&
2712                     dev_bytenr == block_ctx.dev_bytenr) {
2713                         match++;
2714                         btrfsic_release_block_ctx(&block_ctx);
2715                         break;
2716                 }
2717                 btrfsic_release_block_ctx(&block_ctx);
2718         }
2719
2720         if (WARN_ON(!match)) {
2721                 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",
2722                        bytenr, dev_state->name, dev_bytenr);
2723                 for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
2724                         ret = btrfsic_map_block(state, bytenr,
2725                                                 state->metablock_size,
2726                                                 &block_ctx, mirror_num);
2727                         if (ret)
2728                                 continue;
2729
2730                         pr_info("Read logical bytenr @%llu maps to (%s/%llu/%d)\n",
2731                                bytenr, block_ctx.dev->name,
2732                                block_ctx.dev_bytenr, mirror_num);
2733                 }
2734         }
2735 }
2736
2737 static struct btrfsic_dev_state *btrfsic_dev_state_lookup(
2738                 struct block_device *bdev)
2739 {
2740         return btrfsic_dev_state_hashtable_lookup(bdev,
2741                                                   &btrfsic_dev_state_hashtable);
2742 }
2743
2744 int btrfsic_submit_bh(int op, int op_flags, struct buffer_head *bh)
2745 {
2746         struct btrfsic_dev_state *dev_state;
2747
2748         if (!btrfsic_is_initialized)
2749                 return submit_bh(op, op_flags, bh);
2750
2751         mutex_lock(&btrfsic_mutex);
2752         /* since btrfsic_submit_bh() might also be called before
2753          * btrfsic_mount(), this might return NULL */
2754         dev_state = btrfsic_dev_state_lookup(bh->b_bdev);
2755
2756         /* Only called to write the superblock (incl. FLUSH/FUA) */
2757         if (NULL != dev_state &&
2758             (op == REQ_OP_WRITE) && bh->b_size > 0) {
2759                 u64 dev_bytenr;
2760
2761                 dev_bytenr = BTRFS_BDEV_BLOCKSIZE * bh->b_blocknr;
2762                 if (dev_state->state->print_mask &
2763                     BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
2764                         pr_info("submit_bh(op=0x%x,0x%x, blocknr=%llu (bytenr %llu), size=%zu, data=%p, bdev=%p)\n",
2765                                op, op_flags, (unsigned long long)bh->b_blocknr,
2766                                dev_bytenr, bh->b_size, bh->b_data, bh->b_bdev);
2767                 btrfsic_process_written_block(dev_state, dev_bytenr,
2768                                               &bh->b_data, 1, NULL,
2769                                               NULL, bh, op_flags);
2770         } else if (NULL != dev_state && (op_flags & REQ_PREFLUSH)) {
2771                 if (dev_state->state->print_mask &
2772                     BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
2773                         pr_info("submit_bh(op=0x%x,0x%x FLUSH, bdev=%p)\n",
2774                                op, op_flags, bh->b_bdev);
2775                 if (!dev_state->dummy_block_for_bio_bh_flush.is_iodone) {
2776                         if ((dev_state->state->print_mask &
2777                              (BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH |
2778                               BTRFSIC_PRINT_MASK_VERBOSE)))
2779                                 pr_info("btrfsic_submit_bh(%s) with FLUSH but dummy block already in use (ignored)!\n",
2780                                        dev_state->name);
2781                 } else {
2782                         struct btrfsic_block *const block =
2783                                 &dev_state->dummy_block_for_bio_bh_flush;
2784
2785                         block->is_iodone = 0;
2786                         block->never_written = 0;
2787                         block->iodone_w_error = 0;
2788                         block->flush_gen = dev_state->last_flush_gen + 1;
2789                         block->submit_bio_bh_rw = op_flags;
2790                         block->orig_bio_bh_private = bh->b_private;
2791                         block->orig_bio_bh_end_io.bh = bh->b_end_io;
2792                         block->next_in_same_bio = NULL;
2793                         bh->b_private = block;
2794                         bh->b_end_io = btrfsic_bh_end_io;
2795                 }
2796         }
2797         mutex_unlock(&btrfsic_mutex);
2798         return submit_bh(op, op_flags, bh);
2799 }
2800
2801 static void __btrfsic_submit_bio(struct bio *bio)
2802 {
2803         struct btrfsic_dev_state *dev_state;
2804
2805         if (!btrfsic_is_initialized)
2806                 return;
2807
2808         mutex_lock(&btrfsic_mutex);
2809         /* since btrfsic_submit_bio() is also called before
2810          * btrfsic_mount(), this might return NULL */
2811         dev_state = btrfsic_dev_state_lookup(bio->bi_bdev);
2812         if (NULL != dev_state &&
2813             (bio_op(bio) == REQ_OP_WRITE) && bio_has_data(bio)) {
2814                 unsigned int i = 0;
2815                 u64 dev_bytenr;
2816                 u64 cur_bytenr;
2817                 struct bio_vec bvec;
2818                 struct bvec_iter iter;
2819                 int bio_is_patched;
2820                 char **mapped_datav;
2821                 unsigned int segs = bio_segments(bio);
2822
2823                 dev_bytenr = 512 * bio->bi_iter.bi_sector;
2824                 bio_is_patched = 0;
2825                 if (dev_state->state->print_mask &
2826                     BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
2827                         pr_info("submit_bio(rw=%d,0x%x, bi_vcnt=%u, bi_sector=%llu (bytenr %llu), bi_bdev=%p)\n",
2828                                bio_op(bio), bio->bi_opf, segs,
2829                                (unsigned long long)bio->bi_iter.bi_sector,
2830                                dev_bytenr, bio->bi_bdev);
2831
2832                 mapped_datav = kmalloc_array(segs,
2833                                              sizeof(*mapped_datav), GFP_NOFS);
2834                 if (!mapped_datav)
2835                         goto leave;
2836                 cur_bytenr = dev_bytenr;
2837
2838                 bio_for_each_segment(bvec, bio, iter) {
2839                         BUG_ON(bvec.bv_len != PAGE_SIZE);
2840                         mapped_datav[i] = kmap(bvec.bv_page);
2841                         i++;
2842
2843                         if (dev_state->state->print_mask &
2844                             BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH_VERBOSE)
2845                                 pr_info("#%u: bytenr=%llu, len=%u, offset=%u\n",
2846                                        i, cur_bytenr, bvec.bv_len, bvec.bv_offset);
2847                         cur_bytenr += bvec.bv_len;
2848                 }
2849                 btrfsic_process_written_block(dev_state, dev_bytenr,
2850                                               mapped_datav, segs,
2851                                               bio, &bio_is_patched,
2852                                               NULL, bio->bi_opf);
2853                 bio_for_each_segment(bvec, bio, iter)
2854                         kunmap(bvec.bv_page);
2855                 kfree(mapped_datav);
2856         } else if (NULL != dev_state && (bio->bi_opf & REQ_PREFLUSH)) {
2857                 if (dev_state->state->print_mask &
2858                     BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
2859                         pr_info("submit_bio(rw=%d,0x%x FLUSH, bdev=%p)\n",
2860                                bio_op(bio), bio->bi_opf, bio->bi_bdev);
2861                 if (!dev_state->dummy_block_for_bio_bh_flush.is_iodone) {
2862                         if ((dev_state->state->print_mask &
2863                              (BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH |
2864                               BTRFSIC_PRINT_MASK_VERBOSE)))
2865                                 pr_info("btrfsic_submit_bio(%s) with FLUSH but dummy block already in use (ignored)!\n",
2866                                        dev_state->name);
2867                 } else {
2868                         struct btrfsic_block *const block =
2869                                 &dev_state->dummy_block_for_bio_bh_flush;
2870
2871                         block->is_iodone = 0;
2872                         block->never_written = 0;
2873                         block->iodone_w_error = 0;
2874                         block->flush_gen = dev_state->last_flush_gen + 1;
2875                         block->submit_bio_bh_rw = bio->bi_opf;
2876                         block->orig_bio_bh_private = bio->bi_private;
2877                         block->orig_bio_bh_end_io.bio = bio->bi_end_io;
2878                         block->next_in_same_bio = NULL;
2879                         bio->bi_private = block;
2880                         bio->bi_end_io = btrfsic_bio_end_io;
2881                 }
2882         }
2883 leave:
2884         mutex_unlock(&btrfsic_mutex);
2885 }
2886
2887 void btrfsic_submit_bio(struct bio *bio)
2888 {
2889         __btrfsic_submit_bio(bio);
2890         submit_bio(bio);
2891 }
2892
2893 int btrfsic_submit_bio_wait(struct bio *bio)
2894 {
2895         __btrfsic_submit_bio(bio);
2896         return submit_bio_wait(bio);
2897 }
2898
2899 int btrfsic_mount(struct btrfs_fs_info *fs_info,
2900                   struct btrfs_fs_devices *fs_devices,
2901                   int including_extent_data, u32 print_mask)
2902 {
2903         int ret;
2904         struct btrfsic_state *state;
2905         struct list_head *dev_head = &fs_devices->devices;
2906         struct btrfs_device *device;
2907
2908         if (fs_info->nodesize & ((u64)PAGE_SIZE - 1)) {
2909                 pr_info("btrfsic: cannot handle nodesize %d not being a multiple of PAGE_SIZE %ld!\n",
2910                        fs_info->nodesize, PAGE_SIZE);
2911                 return -1;
2912         }
2913         if (fs_info->sectorsize & ((u64)PAGE_SIZE - 1)) {
2914                 pr_info("btrfsic: cannot handle sectorsize %d not being a multiple of PAGE_SIZE %ld!\n",
2915                        fs_info->sectorsize, PAGE_SIZE);
2916                 return -1;
2917         }
2918         state = kvzalloc(sizeof(*state), GFP_KERNEL);
2919         if (!state) {
2920                 pr_info("btrfs check-integrity: allocation failed!\n");
2921                 return -1;
2922         }
2923
2924         if (!btrfsic_is_initialized) {
2925                 mutex_init(&btrfsic_mutex);
2926                 btrfsic_dev_state_hashtable_init(&btrfsic_dev_state_hashtable);
2927                 btrfsic_is_initialized = 1;
2928         }
2929         mutex_lock(&btrfsic_mutex);
2930         state->fs_info = fs_info;
2931         state->print_mask = print_mask;
2932         state->include_extent_data = including_extent_data;
2933         state->csum_size = 0;
2934         state->metablock_size = fs_info->nodesize;
2935         state->datablock_size = fs_info->sectorsize;
2936         INIT_LIST_HEAD(&state->all_blocks_list);
2937         btrfsic_block_hashtable_init(&state->block_hashtable);
2938         btrfsic_block_link_hashtable_init(&state->block_link_hashtable);
2939         state->max_superblock_generation = 0;
2940         state->latest_superblock = NULL;
2941
2942         list_for_each_entry(device, dev_head, dev_list) {
2943                 struct btrfsic_dev_state *ds;
2944                 const char *p;
2945
2946                 if (!device->bdev || !device->name)
2947                         continue;
2948
2949                 ds = btrfsic_dev_state_alloc();
2950                 if (NULL == ds) {
2951                         pr_info("btrfs check-integrity: kmalloc() failed!\n");
2952                         mutex_unlock(&btrfsic_mutex);
2953                         return -1;
2954                 }
2955                 ds->bdev = device->bdev;
2956                 ds->state = state;
2957                 bdevname(ds->bdev, ds->name);
2958                 ds->name[BDEVNAME_SIZE - 1] = '\0';
2959                 p = kbasename(ds->name);
2960                 strlcpy(ds->name, p, sizeof(ds->name));
2961                 btrfsic_dev_state_hashtable_add(ds,
2962                                                 &btrfsic_dev_state_hashtable);
2963         }
2964
2965         ret = btrfsic_process_superblock(state, fs_devices);
2966         if (0 != ret) {
2967                 mutex_unlock(&btrfsic_mutex);
2968                 btrfsic_unmount(fs_devices);
2969                 return ret;
2970         }
2971
2972         if (state->print_mask & BTRFSIC_PRINT_MASK_INITIAL_DATABASE)
2973                 btrfsic_dump_database(state);
2974         if (state->print_mask & BTRFSIC_PRINT_MASK_INITIAL_TREE)
2975                 btrfsic_dump_tree(state);
2976
2977         mutex_unlock(&btrfsic_mutex);
2978         return 0;
2979 }
2980
2981 void btrfsic_unmount(struct btrfs_fs_devices *fs_devices)
2982 {
2983         struct btrfsic_block *b_all, *tmp_all;
2984         struct btrfsic_state *state;
2985         struct list_head *dev_head = &fs_devices->devices;
2986         struct btrfs_device *device;
2987
2988         if (!btrfsic_is_initialized)
2989                 return;
2990
2991         mutex_lock(&btrfsic_mutex);
2992
2993         state = NULL;
2994         list_for_each_entry(device, dev_head, dev_list) {
2995                 struct btrfsic_dev_state *ds;
2996
2997                 if (!device->bdev || !device->name)
2998                         continue;
2999
3000                 ds = btrfsic_dev_state_hashtable_lookup(
3001                                 device->bdev,
3002                                 &btrfsic_dev_state_hashtable);
3003                 if (NULL != ds) {
3004                         state = ds->state;
3005                         btrfsic_dev_state_hashtable_remove(ds);
3006                         btrfsic_dev_state_free(ds);
3007                 }
3008         }
3009
3010         if (NULL == state) {
3011                 pr_info("btrfsic: error, cannot find state information on umount!\n");
3012                 mutex_unlock(&btrfsic_mutex);
3013                 return;
3014         }
3015
3016         /*
3017          * Don't care about keeping the lists' state up to date,
3018          * just free all memory that was allocated dynamically.
3019          * Free the blocks and the block_links.
3020          */
3021         list_for_each_entry_safe(b_all, tmp_all, &state->all_blocks_list,
3022                                  all_blocks_node) {
3023                 struct btrfsic_block_link *l, *tmp;
3024
3025                 list_for_each_entry_safe(l, tmp, &b_all->ref_to_list,
3026                                          node_ref_to) {
3027                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
3028                                 btrfsic_print_rem_link(state, l);
3029
3030                         l->ref_cnt--;
3031                         if (0 == l->ref_cnt)
3032                                 btrfsic_block_link_free(l);
3033                 }
3034
3035                 if (b_all->is_iodone || b_all->never_written)
3036                         btrfsic_block_free(b_all);
3037                 else
3038                         pr_info("btrfs: attempt to free %c-block @%llu (%s/%llu/%d) on umount which is not yet iodone!\n",
3039                                btrfsic_get_block_type(state, b_all),
3040                                b_all->logical_bytenr, b_all->dev_state->name,
3041                                b_all->dev_bytenr, b_all->mirror_num);
3042         }
3043
3044         mutex_unlock(&btrfsic_mutex);
3045
3046         kvfree(state);
3047 }