fs/btrfs/check-integrity.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) STRATO AG 2011.  All rights reserved.
   4  */
   5
   6 /*
   7  * This module can be used to catch cases when the btrfs kernel
   8  * code executes write requests to the disk that bring the file
   9  * system in an inconsistent state. In such a state, a power-loss
  10  * or kernel panic event would cause that the data on disk is
  11  * lost or at least damaged.
  12  *
  13  * Code is added that examines all block write requests during
  14  * runtime (including writes of the super block). Three rules
  15  * are verified and an error is printed on violation of the
  16  * rules:
  17  * 1. It is not allowed to write a disk block which is
  18  *    currently referenced by the super block (either directly
  19  *    or indirectly).
  20  * 2. When a super block is written, it is verified that all
  21  *    referenced (directly or indirectly) blocks fulfill the
  22  *    following requirements:
  23  *    2a. All referenced blocks have either been present when
  24  *        the file system was mounted, (i.e., they have been
  25  *        referenced by the super block) or they have been
  26  *        written since then and the write completion callback
  27  *        was called and no write error was indicated and a
  28  *        FLUSH request to the device where these blocks are
  29  *        located was received and completed.
  30  *    2b. All referenced blocks need to have a generation
  31  *        number which is equal to the parent's number.
  32  *
  33  * One issue that was found using this module was that the log
  34  * tree on disk became temporarily corrupted because disk blocks
  35  * that had been in use for the log tree had been freed and
  36  * reused too early, while being referenced by the written super
  37  * block.
  38  *
  39  * The search term in the kernel log that can be used to filter
  40  * on the existence of detected integrity issues is
  41  * "btrfs: attempt".
  42  *
  43  * The integrity check is enabled via mount options. These
  44  * mount options are only supported if the integrity check
  45  * tool is compiled by defining BTRFS_FS_CHECK_INTEGRITY.
  46  *
  47  * Example #1, apply integrity checks to all metadata:
  48  * mount /dev/sdb1 /mnt -o check_int
  49  *
  50  * Example #2, apply integrity checks to all metadata and
  51  * to data extents:
  52  * mount /dev/sdb1 /mnt -o check_int_data
  53  *
  54  * Example #3, apply integrity checks to all metadata and dump
  55  * the tree that the super block references to kernel messages
  56  * each time after a super block was written:
  57  * mount /dev/sdb1 /mnt -o check_int,check_int_print_mask=263
  58  *
  59  * If the integrity check tool is included and activated in
  60  * the mount options, plenty of kernel memory is used, and
  61  * plenty of additional CPU cycles are spent. Enabling this
  62  * functionality is not intended for normal use. In most
  63  * cases, unless you are a btrfs developer who needs to verify
  64  * the integrity of (super)-block write requests, do not
  65  * enable the config option BTRFS_FS_CHECK_INTEGRITY to
  66  * include and compile the integrity check tool.
  67  *
  68  * Expect millions of lines of information in the kernel log with an
  69  * enabled check_int_print_mask. Therefore set LOG_BUF_SHIFT in the
  70  * kernel config to at least 26 (which is 64MB). Usually the value is
  71  * limited to 21 (which is 2MB) in init/Kconfig. The file needs to be
  72  * changed like this before LOG_BUF_SHIFT can be set to a high value:
  73  * config LOG_BUF_SHIFT
  74  *       int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
  75  *       range 12 30
  76  */
  77
  78 #include <linux/sched.h>
  79 #include <linux/slab.h>
  80 #include <linux/mutex.h>
  81 #include <linux/blkdev.h>
  82 #include <linux/mm.h>
  83 #include <linux/string.h>
  84 #include <crypto/hash.h>
  85 #include "ctree.h"
  86 #include "disk-io.h"
  87 #include "transaction.h"
  88 #include "extent_io.h"
  89 #include "volumes.h"
  90 #include "print-tree.h"
  91 #include "locking.h"
  92 #include "check-integrity.h"
  93 #include "rcu-string.h"
  94 #include "compression.h"
  95
  96 #define BTRFSIC_BLOCK_HASHTABLE_SIZE 0x10000
  97 #define BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE 0x10000
  98 #define BTRFSIC_DEV2STATE_HASHTABLE_SIZE 0x100
  99 #define BTRFSIC_BLOCK_MAGIC_NUMBER 0x14491051
 100 #define BTRFSIC_BLOCK_LINK_MAGIC_NUMBER 0x11070807
 101 #define BTRFSIC_DEV2STATE_MAGIC_NUMBER 0x20111530
 102 #define BTRFSIC_BLOCK_STACK_FRAME_MAGIC_NUMBER 20111300
 103 #define BTRFSIC_TREE_DUMP_MAX_INDENT_LEVEL (200 - 6)    /* in characters,
 104                                                          * excluding " [...]" */
 105 #define BTRFSIC_GENERATION_UNKNOWN ((u64)-1)
 106
 107 /*
 108  * The definition of the bitmask fields for the print_mask.
 109  * They are specified with the mount option check_integrity_print_mask.
 110  */
 111 #define BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE                     0x00000001
 112 #define BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION         0x00000002
 113 #define BTRFSIC_PRINT_MASK_TREE_AFTER_SB_WRITE                  0x00000004
 114 #define BTRFSIC_PRINT_MASK_TREE_BEFORE_SB_WRITE                 0x00000008
 115 #define BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH                        0x00000010
 116 #define BTRFSIC_PRINT_MASK_END_IO_BIO_BH                        0x00000020
 117 #define BTRFSIC_PRINT_MASK_VERBOSE                              0x00000040
 118 #define BTRFSIC_PRINT_MASK_VERY_VERBOSE                         0x00000080
 119 #define BTRFSIC_PRINT_MASK_INITIAL_TREE                         0x00000100
 120 #define BTRFSIC_PRINT_MASK_INITIAL_ALL_TREES                    0x00000200
 121 #define BTRFSIC_PRINT_MASK_INITIAL_DATABASE                     0x00000400
 122 #define BTRFSIC_PRINT_MASK_NUM_COPIES                           0x00000800
 123 #define BTRFSIC_PRINT_MASK_TREE_WITH_ALL_MIRRORS                0x00001000
 124 #define BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH_VERBOSE                0x00002000
 125
 126 struct btrfsic_dev_state;
 127 struct btrfsic_state;
 128
 129 struct btrfsic_block {
 130         u32 magic_num;          /* only used for debug purposes */
 131         unsigned int is_metadata:1;     /* if it is meta-data, not data-data */
 132         unsigned int is_superblock:1;   /* if it is one of the superblocks */
 133         unsigned int is_iodone:1;       /* if is done by lower subsystem */
 134         unsigned int iodone_w_error:1;  /* error was indicated to endio */
 135         unsigned int never_written:1;   /* block was added because it was
 136                                          * referenced, not because it was
 137                                          * written */
 138         unsigned int mirror_num;        /* large enough to hold
 139                                          * BTRFS_SUPER_MIRROR_MAX */
 140         struct btrfsic_dev_state *dev_state;
 141         u64 dev_bytenr;         /* key, physical byte num on disk */
 142         u64 logical_bytenr;     /* logical byte num on disk */
 143         u64 generation;
 144         struct btrfs_disk_key disk_key; /* extra info to print in case of
 145                                          * issues, will not always be correct */
 146         struct list_head collision_resolving_node;      /* list node */
 147         struct list_head all_blocks_node;       /* list node */
 148
 149         /* the following two lists contain block_link items */
 150         struct list_head ref_to_list;   /* list */
 151         struct list_head ref_from_list; /* list */
 152         struct btrfsic_block *next_in_same_bio;
 153         void *orig_bio_private;
 154         bio_end_io_t *orig_bio_end_io;
 155         blk_opf_t submit_bio_bh_rw;
 156         u64 flush_gen; /* only valid if !never_written */
 157 };
 158
 159 /*
 160  * Elements of this type are allocated dynamically and required because
 161  * each block object can refer to and can be ref from multiple blocks.
 162  * The key to lookup them in the hashtable is the dev_bytenr of
 163  * the block ref to plus the one from the block referred from.
 164  * The fact that they are searchable via a hashtable and that a
 165  * ref_cnt is maintained is not required for the btrfs integrity
 166  * check algorithm itself, it is only used to make the output more
 167  * beautiful in case that an error is detected (an error is defined
 168  * as a write operation to a block while that block is still referenced).
 169  */
 170 struct btrfsic_block_link {
 171         u32 magic_num;          /* only used for debug purposes */
 172         u32 ref_cnt;
 173         struct list_head node_ref_to;   /* list node */
 174         struct list_head node_ref_from; /* list node */
 175         struct list_head collision_resolving_node;      /* list node */
 176         struct btrfsic_block *block_ref_to;
 177         struct btrfsic_block *block_ref_from;
 178         u64 parent_generation;
 179 };
 180
 181 struct btrfsic_dev_state {
 182         u32 magic_num;          /* only used for debug purposes */
 183         struct block_device *bdev;
 184         struct btrfsic_state *state;
 185         struct list_head collision_resolving_node;      /* list node */
 186         struct btrfsic_block dummy_block_for_bio_bh_flush;
 187         u64 last_flush_gen;
 188 };
 189
 190 struct btrfsic_block_hashtable {
 191         struct list_head table[BTRFSIC_BLOCK_HASHTABLE_SIZE];
 192 };
 193
 194 struct btrfsic_block_link_hashtable {
 195         struct list_head table[BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE];
 196 };
 197
 198 struct btrfsic_dev_state_hashtable {
 199         struct list_head table[BTRFSIC_DEV2STATE_HASHTABLE_SIZE];
 200 };
 201
 202 struct btrfsic_block_data_ctx {
 203         u64 start;              /* virtual bytenr */
 204         u64 dev_bytenr;         /* physical bytenr on device */
 205         u32 len;
 206         struct btrfsic_dev_state *dev;
 207         char **datav;
 208         struct page **pagev;
 209         void *mem_to_free;
 210 };
 211
 212 /* This structure is used to implement recursion without occupying
 213  * any stack space, refer to btrfsic_process_metablock() */
 214 struct btrfsic_stack_frame {
 215         u32 magic;
 216         u32 nr;
 217         int error;
 218         int i;
 219         int limit_nesting;
 220         int num_copies;
 221         int mirror_num;
 222         struct btrfsic_block *block;
 223         struct btrfsic_block_data_ctx *block_ctx;
 224         struct btrfsic_block *next_block;
 225         struct btrfsic_block_data_ctx next_block_ctx;
 226         struct btrfs_header *hdr;
 227         struct btrfsic_stack_frame *prev;
 228 };
 229
 230 /* Some state per mounted filesystem */
 231 struct btrfsic_state {
 232         u32 print_mask;
 233         int include_extent_data;
 234         struct list_head all_blocks_list;
 235         struct btrfsic_block_hashtable block_hashtable;
 236         struct btrfsic_block_link_hashtable block_link_hashtable;
 237         struct btrfs_fs_info *fs_info;
 238         u64 max_superblock_generation;
 239         struct btrfsic_block *latest_superblock;
 240         u32 metablock_size;
 241         u32 datablock_size;
 242 };
 243
 244 static int btrfsic_process_metablock(struct btrfsic_state *state,
 245                                      struct btrfsic_block *block,
 246                                      struct btrfsic_block_data_ctx *block_ctx,
 247                                      int limit_nesting, int force_iodone_flag);
 248 static void btrfsic_read_from_block_data(
 249         struct btrfsic_block_data_ctx *block_ctx,
 250         void *dst, u32 offset, size_t len);
 251 static int btrfsic_create_link_to_next_block(
 252                 struct btrfsic_state *state,
 253                 struct btrfsic_block *block,
 254                 struct btrfsic_block_data_ctx
 255                 *block_ctx, u64 next_bytenr,
 256                 int limit_nesting,
 257                 struct btrfsic_block_data_ctx *next_block_ctx,
 258                 struct btrfsic_block **next_blockp,
 259                 int force_iodone_flag,
 260                 int *num_copiesp, int *mirror_nump,
 261                 struct btrfs_disk_key *disk_key,
 262                 u64 parent_generation);
 263 static int btrfsic_handle_extent_data(struct btrfsic_state *state,
 264                                       struct btrfsic_block *block,
 265                                       struct btrfsic_block_data_ctx *block_ctx,
 266                                       u32 item_offset, int force_iodone_flag);
 267 static int btrfsic_map_block(struct btrfsic_state *state, u64 bytenr, u32 len,
 268                              struct btrfsic_block_data_ctx *block_ctx_out,
 269                              int mirror_num);
 270 static void btrfsic_release_block_ctx(struct btrfsic_block_data_ctx *block_ctx);
 271 static int btrfsic_read_block(struct btrfsic_state *state,
 272                               struct btrfsic_block_data_ctx *block_ctx);
 273 static int btrfsic_process_written_superblock(
 274                 struct btrfsic_state *state,
 275                 struct btrfsic_block *const block,
 276                 struct btrfs_super_block *const super_hdr);
 277 static void btrfsic_bio_end_io(struct bio *bp);
 278 static int btrfsic_is_block_ref_by_superblock(const struct btrfsic_state *state,
 279                                               const struct btrfsic_block *block,
 280                                               int recursion_level);
 281 static int btrfsic_check_all_ref_blocks(struct btrfsic_state *state,
 282                                         struct btrfsic_block *const block,
 283                                         int recursion_level);
 284 static void btrfsic_print_add_link(const struct btrfsic_state *state,
 285                                    const struct btrfsic_block_link *l);
 286 static void btrfsic_print_rem_link(const struct btrfsic_state *state,
 287                                    const struct btrfsic_block_link *l);
 288 static char btrfsic_get_block_type(const struct btrfsic_state *state,
 289                                    const struct btrfsic_block *block);
 290 static void btrfsic_dump_tree(const struct btrfsic_state *state);
 291 static void btrfsic_dump_tree_sub(const struct btrfsic_state *state,
 292                                   const struct btrfsic_block *block,
 293                                   int indent_level);
 294 static struct btrfsic_block_link *btrfsic_block_link_lookup_or_add(
 295                 struct btrfsic_state *state,
 296                 struct btrfsic_block_data_ctx *next_block_ctx,
 297                 struct btrfsic_block *next_block,
 298                 struct btrfsic_block *from_block,
 299                 u64 parent_generation);
 300 static struct btrfsic_block *btrfsic_block_lookup_or_add(
 301                 struct btrfsic_state *state,
 302                 struct btrfsic_block_data_ctx *block_ctx,
 303                 const char *additional_string,
 304                 int is_metadata,
 305                 int is_iodone,
 306                 int never_written,
 307                 int mirror_num,
 308                 int *was_created);
 309 static int btrfsic_process_superblock_dev_mirror(
 310                 struct btrfsic_state *state,
 311                 struct btrfsic_dev_state *dev_state,
 312                 struct btrfs_device *device,
 313                 int superblock_mirror_num,
 314                 struct btrfsic_dev_state **selected_dev_state,
 315                 struct btrfs_super_block *selected_super);
 316 static struct btrfsic_dev_state *btrfsic_dev_state_lookup(dev_t dev);
 317 static void btrfsic_cmp_log_and_dev_bytenr(struct btrfsic_state *state,
 318                                            u64 bytenr,
 319                                            struct btrfsic_dev_state *dev_state,
 320                                            u64 dev_bytenr);
 321
 322 static struct mutex btrfsic_mutex;
 323 static int btrfsic_is_initialized;
 324 static struct btrfsic_dev_state_hashtable btrfsic_dev_state_hashtable;
 325
 326
 327 static void btrfsic_block_init(struct btrfsic_block *b)
 328 {
 329         b->magic_num = BTRFSIC_BLOCK_MAGIC_NUMBER;
 330         b->dev_state = NULL;
 331         b->dev_bytenr = 0;
 332         b->logical_bytenr = 0;
 333         b->generation = BTRFSIC_GENERATION_UNKNOWN;
 334         b->disk_key.objectid = 0;
 335         b->disk_key.type = 0;
 336         b->disk_key.offset = 0;
 337         b->is_metadata = 0;
 338         b->is_superblock = 0;
 339         b->is_iodone = 0;
 340         b->iodone_w_error = 0;
 341         b->never_written = 0;
 342         b->mirror_num = 0;
 343         b->next_in_same_bio = NULL;
 344         b->orig_bio_private = NULL;
 345         b->orig_bio_end_io = NULL;
 346         INIT_LIST_HEAD(&b->collision_resolving_node);
 347         INIT_LIST_HEAD(&b->all_blocks_node);
 348         INIT_LIST_HEAD(&b->ref_to_list);
 349         INIT_LIST_HEAD(&b->ref_from_list);
 350         b->submit_bio_bh_rw = 0;
 351         b->flush_gen = 0;
 352 }
 353
 354 static struct btrfsic_block *btrfsic_block_alloc(void)
 355 {
 356         struct btrfsic_block *b;
 357
 358         b = kzalloc(sizeof(*b), GFP_NOFS);
 359         if (NULL != b)
 360                 btrfsic_block_init(b);
 361
 362         return b;
 363 }
 364
 365 static void btrfsic_block_free(struct btrfsic_block *b)
 366 {
 367         BUG_ON(!(NULL == b || BTRFSIC_BLOCK_MAGIC_NUMBER == b->magic_num));
 368         kfree(b);
 369 }
 370
 371 static void btrfsic_block_link_init(struct btrfsic_block_link *l)
 372 {
 373         l->magic_num = BTRFSIC_BLOCK_LINK_MAGIC_NUMBER;
 374         l->ref_cnt = 1;
 375         INIT_LIST_HEAD(&l->node_ref_to);
 376         INIT_LIST_HEAD(&l->node_ref_from);
 377         INIT_LIST_HEAD(&l->collision_resolving_node);
 378         l->block_ref_to = NULL;
 379         l->block_ref_from = NULL;
 380 }
 381
 382 static struct btrfsic_block_link *btrfsic_block_link_alloc(void)
 383 {
 384         struct btrfsic_block_link *l;
 385
 386         l = kzalloc(sizeof(*l), GFP_NOFS);
 387         if (NULL != l)
 388                 btrfsic_block_link_init(l);
 389
 390         return l;
 391 }
 392
 393 static void btrfsic_block_link_free(struct btrfsic_block_link *l)
 394 {
 395         BUG_ON(!(NULL == l || BTRFSIC_BLOCK_LINK_MAGIC_NUMBER == l->magic_num));
 396         kfree(l);
 397 }
 398
 399 static void btrfsic_dev_state_init(struct btrfsic_dev_state *ds)
 400 {
 401         ds->magic_num = BTRFSIC_DEV2STATE_MAGIC_NUMBER;
 402         ds->bdev = NULL;
 403         ds->state = NULL;
 404         INIT_LIST_HEAD(&ds->collision_resolving_node);
 405         ds->last_flush_gen = 0;
 406         btrfsic_block_init(&ds->dummy_block_for_bio_bh_flush);
 407         ds->dummy_block_for_bio_bh_flush.is_iodone = 1;
 408         ds->dummy_block_for_bio_bh_flush.dev_state = ds;
 409 }
 410
 411 static struct btrfsic_dev_state *btrfsic_dev_state_alloc(void)
 412 {
 413         struct btrfsic_dev_state *ds;
 414
 415         ds = kzalloc(sizeof(*ds), GFP_NOFS);
 416         if (NULL != ds)
 417                 btrfsic_dev_state_init(ds);
 418
 419         return ds;
 420 }
 421
 422 static void btrfsic_dev_state_free(struct btrfsic_dev_state *ds)
 423 {
 424         BUG_ON(!(NULL == ds ||
 425                  BTRFSIC_DEV2STATE_MAGIC_NUMBER == ds->magic_num));
 426         kfree(ds);
 427 }
 428
 429 static void btrfsic_block_hashtable_init(struct btrfsic_block_hashtable *h)
 430 {
 431         int i;
 432
 433         for (i = 0; i < BTRFSIC_BLOCK_HASHTABLE_SIZE; i++)
 434                 INIT_LIST_HEAD(h->table + i);
 435 }
 436
 437 static void btrfsic_block_hashtable_add(struct btrfsic_block *b,
 438                                         struct btrfsic_block_hashtable *h)
 439 {
 440         const unsigned int hashval =
 441             (((unsigned int)(b->dev_bytenr >> 16)) ^
 442              ((unsigned int)((uintptr_t)b->dev_state->bdev))) &
 443              (BTRFSIC_BLOCK_HASHTABLE_SIZE - 1);
 444
 445         list_add(&b->collision_resolving_node, h->table + hashval);
 446 }
 447
 448 static void btrfsic_block_hashtable_remove(struct btrfsic_block *b)
 449 {
 450         list_del(&b->collision_resolving_node);
 451 }
 452
 453 static struct btrfsic_block *btrfsic_block_hashtable_lookup(
 454                 struct block_device *bdev,
 455                 u64 dev_bytenr,
 456                 struct btrfsic_block_hashtable *h)
 457 {
 458         const unsigned int hashval =
 459             (((unsigned int)(dev_bytenr >> 16)) ^
 460              ((unsigned int)((uintptr_t)bdev))) &
 461              (BTRFSIC_BLOCK_HASHTABLE_SIZE - 1);
 462         struct btrfsic_block *b;
 463
 464         list_for_each_entry(b, h->table + hashval, collision_resolving_node) {
 465                 if (b->dev_state->bdev == bdev && b->dev_bytenr == dev_bytenr)
 466                         return b;
 467         }
 468
 469         return NULL;
 470 }
 471
 472 static void btrfsic_block_link_hashtable_init(
 473                 struct btrfsic_block_link_hashtable *h)
 474 {
 475         int i;
 476
 477         for (i = 0; i < BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE; i++)
 478                 INIT_LIST_HEAD(h->table + i);
 479 }
 480
 481 static void btrfsic_block_link_hashtable_add(
 482                 struct btrfsic_block_link *l,
 483                 struct btrfsic_block_link_hashtable *h)
 484 {
 485         const unsigned int hashval =
 486             (((unsigned int)(l->block_ref_to->dev_bytenr >> 16)) ^
 487              ((unsigned int)(l->block_ref_from->dev_bytenr >> 16)) ^
 488              ((unsigned int)((uintptr_t)l->block_ref_to->dev_state->bdev)) ^
 489              ((unsigned int)((uintptr_t)l->block_ref_from->dev_state->bdev)))
 490              & (BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE - 1);
 491
 492         BUG_ON(NULL == l->block_ref_to);
 493         BUG_ON(NULL == l->block_ref_from);
 494         list_add(&l->collision_resolving_node, h->table + hashval);
 495 }
 496
 497 static void btrfsic_block_link_hashtable_remove(struct btrfsic_block_link *l)
 498 {
 499         list_del(&l->collision_resolving_node);
 500 }
 501
 502 static struct btrfsic_block_link *btrfsic_block_link_hashtable_lookup(
 503                 struct block_device *bdev_ref_to,
 504                 u64 dev_bytenr_ref_to,
 505                 struct block_device *bdev_ref_from,
 506                 u64 dev_bytenr_ref_from,
 507                 struct btrfsic_block_link_hashtable *h)
 508 {
 509         const unsigned int hashval =
 510             (((unsigned int)(dev_bytenr_ref_to >> 16)) ^
 511              ((unsigned int)(dev_bytenr_ref_from >> 16)) ^
 512              ((unsigned int)((uintptr_t)bdev_ref_to)) ^
 513              ((unsigned int)((uintptr_t)bdev_ref_from))) &
 514              (BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE - 1);
 515         struct btrfsic_block_link *l;
 516
 517         list_for_each_entry(l, h->table + hashval, collision_resolving_node) {
 518                 BUG_ON(NULL == l->block_ref_to);
 519                 BUG_ON(NULL == l->block_ref_from);
 520                 if (l->block_ref_to->dev_state->bdev == bdev_ref_to &&
 521                     l->block_ref_to->dev_bytenr == dev_bytenr_ref_to &&
 522                     l->block_ref_from->dev_state->bdev == bdev_ref_from &&
 523                     l->block_ref_from->dev_bytenr == dev_bytenr_ref_from)
 524                         return l;
 525         }
 526
 527         return NULL;
 528 }
 529
 530 static void btrfsic_dev_state_hashtable_init(
 531                 struct btrfsic_dev_state_hashtable *h)
 532 {
 533         int i;
 534
 535         for (i = 0; i < BTRFSIC_DEV2STATE_HASHTABLE_SIZE; i++)
 536                 INIT_LIST_HEAD(h->table + i);
 537 }
 538
 539 static void btrfsic_dev_state_hashtable_add(
 540                 struct btrfsic_dev_state *ds,
 541                 struct btrfsic_dev_state_hashtable *h)
 542 {
 543         const unsigned int hashval =
 544             (((unsigned int)((uintptr_t)ds->bdev->bd_dev)) &
 545              (BTRFSIC_DEV2STATE_HASHTABLE_SIZE - 1));
 546
 547         list_add(&ds->collision_resolving_node, h->table + hashval);
 548 }
 549
 550 static void btrfsic_dev_state_hashtable_remove(struct btrfsic_dev_state *ds)
 551 {
 552         list_del(&ds->collision_resolving_node);
 553 }
 554
 555 static struct btrfsic_dev_state *btrfsic_dev_state_hashtable_lookup(dev_t dev,
 556                 struct btrfsic_dev_state_hashtable *h)
 557 {
 558         const unsigned int hashval =
 559                 dev & (BTRFSIC_DEV2STATE_HASHTABLE_SIZE - 1);
 560         struct btrfsic_dev_state *ds;
 561
 562         list_for_each_entry(ds, h->table + hashval, collision_resolving_node) {
 563                 if (ds->bdev->bd_dev == dev)
 564                         return ds;
 565         }
 566
 567         return NULL;
 568 }
 569
 570 static int btrfsic_process_superblock(struct btrfsic_state *state,
 571                                       struct btrfs_fs_devices *fs_devices)
 572 {
 573         struct btrfs_super_block *selected_super;
 574         struct list_head *dev_head = &fs_devices->devices;
 575         struct btrfs_device *device;
 576         struct btrfsic_dev_state *selected_dev_state = NULL;
 577         int ret = 0;
 578         int pass;
 579
 580         selected_super = kzalloc(sizeof(*selected_super), GFP_NOFS);
 581         if (!selected_super)
 582                 return -ENOMEM;
 583
 584         list_for_each_entry(device, dev_head, dev_list) {
 585                 int i;
 586                 struct btrfsic_dev_state *dev_state;
 587
 588                 if (!device->bdev || !device->name)
 589                         continue;
 590
 591                 dev_state = btrfsic_dev_state_lookup(device->bdev->bd_dev);
 592                 BUG_ON(NULL == dev_state);
 593                 for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
 594                         ret = btrfsic_process_superblock_dev_mirror(
 595                                         state, dev_state, device, i,
 596                                         &selected_dev_state, selected_super);
 597                         if (0 != ret && 0 == i) {
 598                                 kfree(selected_super);
 599                                 return ret;
 600                         }
 601                 }
 602         }
 603
 604         if (NULL == state->latest_superblock) {
 605                 pr_info("btrfsic: no superblock found!\n");
 606                 kfree(selected_super);
 607                 return -1;
 608         }
 609
 610         for (pass = 0; pass < 3; pass++) {
 611                 int num_copies;
 612                 int mirror_num;
 613                 u64 next_bytenr;
 614
 615                 switch (pass) {
 616                 case 0:
 617                         next_bytenr = btrfs_super_root(selected_super);
 618                         if (state->print_mask &
 619                             BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
 620                                 pr_info("root@%llu\n", next_bytenr);
 621                         break;
 622                 case 1:
 623                         next_bytenr = btrfs_super_chunk_root(selected_super);
 624                         if (state->print_mask &
 625                             BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
 626                                 pr_info("chunk@%llu\n", next_bytenr);
 627                         break;
 628                 case 2:
 629                         next_bytenr = btrfs_super_log_root(selected_super);
 630                         if (0 == next_bytenr)
 631                                 continue;
 632                         if (state->print_mask &
 633                             BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
 634                                 pr_info("log@%llu\n", next_bytenr);
 635                         break;
 636                 }
 637
 638                 num_copies = btrfs_num_copies(state->fs_info, next_bytenr,
 639                                               state->metablock_size);
 640                 if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
 641                         pr_info("num_copies(log_bytenr=%llu) = %d\n",
 642                                next_bytenr, num_copies);
 643
 644                 for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
 645                         struct btrfsic_block *next_block;
 646                         struct btrfsic_block_data_ctx tmp_next_block_ctx;
 647                         struct btrfsic_block_link *l;
 648
 649                         ret = btrfsic_map_block(state, next_bytenr,
 650                                                 state->metablock_size,
 651                                                 &tmp_next_block_ctx,
 652                                                 mirror_num);
 653                         if (ret) {
 654                                 pr_info("btrfsic: btrfsic_map_block(root @%llu, mirror %d) failed!\n",
 655                                        next_bytenr, mirror_num);
 656                                 kfree(selected_super);
 657                                 return -1;
 658                         }
 659
 660                         next_block = btrfsic_block_hashtable_lookup(
 661                                         tmp_next_block_ctx.dev->bdev,
 662                                         tmp_next_block_ctx.dev_bytenr,
 663                                         &state->block_hashtable);
 664                         BUG_ON(NULL == next_block);
 665
 666                         l = btrfsic_block_link_hashtable_lookup(
 667                                         tmp_next_block_ctx.dev->bdev,
 668                                         tmp_next_block_ctx.dev_bytenr,
 669                                         state->latest_superblock->dev_state->
 670                                         bdev,
 671                                         state->latest_superblock->dev_bytenr,
 672                                         &state->block_link_hashtable);
 673                         BUG_ON(NULL == l);
 674
 675                         ret = btrfsic_read_block(state, &tmp_next_block_ctx);
 676                         if (ret < (int)PAGE_SIZE) {
 677                                 pr_info("btrfsic: read @logical %llu failed!\n",
 678                                        tmp_next_block_ctx.start);
 679                                 btrfsic_release_block_ctx(&tmp_next_block_ctx);
 680                                 kfree(selected_super);
 681                                 return -1;
 682                         }
 683
 684                         ret = btrfsic_process_metablock(state,
 685                                                         next_block,
 686                                                         &tmp_next_block_ctx,
 687                                                         BTRFS_MAX_LEVEL + 3, 1);
 688                         btrfsic_release_block_ctx(&tmp_next_block_ctx);
 689                 }
 690         }
 691
 692         kfree(selected_super);
 693         return ret;
 694 }
 695
 696 static int btrfsic_process_superblock_dev_mirror(
 697                 struct btrfsic_state *state,
 698                 struct btrfsic_dev_state *dev_state,
 699                 struct btrfs_device *device,
 700                 int superblock_mirror_num,
 701                 struct btrfsic_dev_state **selected_dev_state,
 702                 struct btrfs_super_block *selected_super)
 703 {
 704         struct btrfs_fs_info *fs_info = state->fs_info;
 705         struct btrfs_super_block *super_tmp;
 706         u64 dev_bytenr;
 707         struct btrfsic_block *superblock_tmp;
 708         int pass;
 709         struct block_device *const superblock_bdev = device->bdev;
 710         struct page *page;
 711         struct address_space *mapping = superblock_bdev->bd_inode->i_mapping;
 712         int ret = 0;
 713
 714         /* super block bytenr is always the unmapped device bytenr */
 715         dev_bytenr = btrfs_sb_offset(superblock_mirror_num);
 716         if (dev_bytenr + BTRFS_SUPER_INFO_SIZE > device->commit_total_bytes)
 717                 return -1;
 718
 719         page = read_cache_page_gfp(mapping, dev_bytenr >> PAGE_SHIFT, GFP_NOFS);
 720         if (IS_ERR(page))
 721                 return -1;
 722
 723         super_tmp = page_address(page);
 724
 725         if (btrfs_super_bytenr(super_tmp) != dev_bytenr ||
 726             btrfs_super_magic(super_tmp) != BTRFS_MAGIC ||
 727             memcmp(device->uuid, super_tmp->dev_item.uuid, BTRFS_UUID_SIZE) ||
 728             btrfs_super_nodesize(super_tmp) != state->metablock_size ||
 729             btrfs_super_sectorsize(super_tmp) != state->datablock_size) {
 730                 ret = 0;
 731                 goto out;
 732         }
 733
 734         superblock_tmp =
 735             btrfsic_block_hashtable_lookup(superblock_bdev,
 736                                            dev_bytenr,
 737                                            &state->block_hashtable);
 738         if (NULL == superblock_tmp) {
 739                 superblock_tmp = btrfsic_block_alloc();
 740                 if (NULL == superblock_tmp) {
 741                         ret = -1;
 742                         goto out;
 743                 }
 744                 /* for superblock, only the dev_bytenr makes sense */
 745                 superblock_tmp->dev_bytenr = dev_bytenr;
 746                 superblock_tmp->dev_state = dev_state;
 747                 superblock_tmp->logical_bytenr = dev_bytenr;
 748                 superblock_tmp->generation = btrfs_super_generation(super_tmp);
 749                 superblock_tmp->is_metadata = 1;
 750                 superblock_tmp->is_superblock = 1;
 751                 superblock_tmp->is_iodone = 1;
 752                 superblock_tmp->never_written = 0;
 753                 superblock_tmp->mirror_num = 1 + superblock_mirror_num;
 754                 if (state->print_mask & BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE)
 755                         btrfs_info_in_rcu(fs_info,
 756                         "new initial S-block (bdev %p, %s) @%llu (%pg/%llu/%d)",
 757                                      superblock_bdev,
 758                                      rcu_str_deref(device->name), dev_bytenr,
 759                                      dev_state->bdev, dev_bytenr,
 760                                      superblock_mirror_num);
 761                 list_add(&superblock_tmp->all_blocks_node,
 762                          &state->all_blocks_list);
 763                 btrfsic_block_hashtable_add(superblock_tmp,
 764                                             &state->block_hashtable);
 765         }
 766
 767         /* select the one with the highest generation field */
 768         if (btrfs_super_generation(super_tmp) >
 769             state->max_superblock_generation ||
 770             0 == state->max_superblock_generation) {
 771                 memcpy(selected_super, super_tmp, sizeof(*selected_super));
 772                 *selected_dev_state = dev_state;
 773                 state->max_superblock_generation =
 774                     btrfs_super_generation(super_tmp);
 775                 state->latest_superblock = superblock_tmp;
 776         }
 777
 778         for (pass = 0; pass < 3; pass++) {
 779                 u64 next_bytenr;
 780                 int num_copies;
 781                 int mirror_num;
 782                 const char *additional_string = NULL;
 783                 struct btrfs_disk_key tmp_disk_key;
 784
 785                 tmp_disk_key.type = BTRFS_ROOT_ITEM_KEY;
 786                 tmp_disk_key.offset = 0;
 787                 switch (pass) {
 788                 case 0:
 789                         btrfs_set_disk_key_objectid(&tmp_disk_key,
 790                                                     BTRFS_ROOT_TREE_OBJECTID);
 791                         additional_string = "initial root ";
 792                         next_bytenr = btrfs_super_root(super_tmp);
 793                         break;
 794                 case 1:
 795                         btrfs_set_disk_key_objectid(&tmp_disk_key,
 796                                                     BTRFS_CHUNK_TREE_OBJECTID);
 797                         additional_string = "initial chunk ";
 798                         next_bytenr = btrfs_super_chunk_root(super_tmp);
 799                         break;
 800                 case 2:
 801                         btrfs_set_disk_key_objectid(&tmp_disk_key,
 802                                                     BTRFS_TREE_LOG_OBJECTID);
 803                         additional_string = "initial log ";
 804                         next_bytenr = btrfs_super_log_root(super_tmp);
 805                         if (0 == next_bytenr)
 806                                 continue;
 807                         break;
 808                 }
 809
 810                 num_copies = btrfs_num_copies(fs_info, next_bytenr,
 811                                               state->metablock_size);
 812                 if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
 813                         pr_info("num_copies(log_bytenr=%llu) = %d\n",
 814                                next_bytenr, num_copies);
 815                 for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
 816                         struct btrfsic_block *next_block;
 817                         struct btrfsic_block_data_ctx tmp_next_block_ctx;
 818                         struct btrfsic_block_link *l;
 819
 820                         if (btrfsic_map_block(state, next_bytenr,
 821                                               state->metablock_size,
 822                                               &tmp_next_block_ctx,
 823                                               mirror_num)) {
 824                                 pr_info("btrfsic: btrfsic_map_block(bytenr @%llu, mirror %d) failed!\n",
 825                                        next_bytenr, mirror_num);
 826                                 ret = -1;
 827                                 goto out;
 828                         }
 829
 830                         next_block = btrfsic_block_lookup_or_add(
 831                                         state, &tmp_next_block_ctx,
 832                                         additional_string, 1, 1, 0,
 833                                         mirror_num, NULL);
 834                         if (NULL == next_block) {
 835                                 btrfsic_release_block_ctx(&tmp_next_block_ctx);
 836                                 ret = -1;
 837                                 goto out;
 838                         }
 839
 840                         next_block->disk_key = tmp_disk_key;
 841                         next_block->generation = BTRFSIC_GENERATION_UNKNOWN;
 842                         l = btrfsic_block_link_lookup_or_add(
 843                                         state, &tmp_next_block_ctx,
 844                                         next_block, superblock_tmp,
 845                                         BTRFSIC_GENERATION_UNKNOWN);
 846                         btrfsic_release_block_ctx(&tmp_next_block_ctx);
 847                         if (NULL == l) {
 848                                 ret = -1;
 849                                 goto out;
 850                         }
 851                 }
 852         }
 853         if (state->print_mask & BTRFSIC_PRINT_MASK_INITIAL_ALL_TREES)
 854                 btrfsic_dump_tree_sub(state, superblock_tmp, 0);
 855
 856 out:
 857         put_page(page);
 858         return ret;
 859 }
 860
 861 static struct btrfsic_stack_frame *btrfsic_stack_frame_alloc(void)
 862 {
 863         struct btrfsic_stack_frame *sf;
 864
 865         sf = kzalloc(sizeof(*sf), GFP_NOFS);
 866         if (sf)
 867                 sf->magic = BTRFSIC_BLOCK_STACK_FRAME_MAGIC_NUMBER;
 868         return sf;
 869 }
 870
 871 static void btrfsic_stack_frame_free(struct btrfsic_stack_frame *sf)
 872 {
 873         BUG_ON(!(NULL == sf ||
 874                  BTRFSIC_BLOCK_STACK_FRAME_MAGIC_NUMBER == sf->magic));
 875         kfree(sf);
 876 }
 877
 878 static noinline_for_stack int btrfsic_process_metablock(
 879                 struct btrfsic_state *state,
 880                 struct btrfsic_block *const first_block,
 881                 struct btrfsic_block_data_ctx *const first_block_ctx,
 882                 int first_limit_nesting, int force_iodone_flag)
 883 {
 884         struct btrfsic_stack_frame initial_stack_frame = { 0 };
 885         struct btrfsic_stack_frame *sf;
 886         struct btrfsic_stack_frame *next_stack;
 887         struct btrfs_header *const first_hdr =
 888                 (struct btrfs_header *)first_block_ctx->datav[0];
 889
 890         BUG_ON(!first_hdr);
 891         sf = &initial_stack_frame;
 892         sf->error = 0;
 893         sf->i = -1;
 894         sf->limit_nesting = first_limit_nesting;
 895         sf->block = first_block;
 896         sf->block_ctx = first_block_ctx;
 897         sf->next_block = NULL;
 898         sf->hdr = first_hdr;
 899         sf->prev = NULL;
 900
 901 continue_with_new_stack_frame:
 902         sf->block->generation = btrfs_stack_header_generation(sf->hdr);
 903         if (0 == sf->hdr->level) {
 904                 struct btrfs_leaf *const leafhdr =
 905                     (struct btrfs_leaf *)sf->hdr;
 906
 907                 if (-1 == sf->i) {
 908                         sf->nr = btrfs_stack_header_nritems(&leafhdr->header);
 909
 910                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
 911                                 pr_info("leaf %llu items %d generation %llu owner %llu\n",
 912                                        sf->block_ctx->start, sf->nr,
 913                                        btrfs_stack_header_generation(
 914                                                &leafhdr->header),
 915                                        btrfs_stack_header_owner(
 916                                                &leafhdr->header));
 917                 }
 918
 919 continue_with_current_leaf_stack_frame:
 920                 if (0 == sf->num_copies || sf->mirror_num > sf->num_copies) {
 921                         sf->i++;
 922                         sf->num_copies = 0;
 923                 }
 924
 925                 if (sf->i < sf->nr) {
 926                         struct btrfs_item disk_item;
 927                         u32 disk_item_offset =
 928                                 (uintptr_t)(leafhdr->items + sf->i) -
 929                                 (uintptr_t)leafhdr;
 930                         struct btrfs_disk_key *disk_key;
 931                         u8 type;
 932                         u32 item_offset;
 933                         u32 item_size;
 934
 935                         if (disk_item_offset + sizeof(struct btrfs_item) >
 936                             sf->block_ctx->len) {
 937 leaf_item_out_of_bounce_error:
 938                                 pr_info(
 939                 "btrfsic: leaf item out of bounce at logical %llu, dev %pg\n",
 940                                        sf->block_ctx->start,
 941                                        sf->block_ctx->dev->bdev);
 942                                 goto one_stack_frame_backwards;
 943                         }
 944                         btrfsic_read_from_block_data(sf->block_ctx,
 945                                                      &disk_item,
 946                                                      disk_item_offset,
 947                                                      sizeof(struct btrfs_item));
 948                         item_offset = btrfs_stack_item_offset(&disk_item);
 949                         item_size = btrfs_stack_item_size(&disk_item);
 950                         disk_key = &disk_item.key;
 951                         type = btrfs_disk_key_type(disk_key);
 952
 953                         if (BTRFS_ROOT_ITEM_KEY == type) {
 954                                 struct btrfs_root_item root_item;
 955                                 u32 root_item_offset;
 956                                 u64 next_bytenr;
 957
 958                                 root_item_offset = item_offset +
 959                                         offsetof(struct btrfs_leaf, items);
 960                                 if (root_item_offset + item_size >
 961                                     sf->block_ctx->len)
 962                                         goto leaf_item_out_of_bounce_error;
 963                                 btrfsic_read_from_block_data(
 964                                         sf->block_ctx, &root_item,
 965                                         root_item_offset,
 966                                         item_size);
 967                                 next_bytenr = btrfs_root_bytenr(&root_item);
 968
 969                                 sf->error =
 970                                     btrfsic_create_link_to_next_block(
 971                                                 state,
 972                                                 sf->block,
 973                                                 sf->block_ctx,
 974                                                 next_bytenr,
 975                                                 sf->limit_nesting,
 976                                                 &sf->next_block_ctx,
 977                                                 &sf->next_block,
 978                                                 force_iodone_flag,
 979                                                 &sf->num_copies,
 980                                                 &sf->mirror_num,
 981                                                 disk_key,
 982                                                 btrfs_root_generation(
 983                                                 &root_item));
 984                                 if (sf->error)
 985                                         goto one_stack_frame_backwards;
 986
 987                                 if (NULL != sf->next_block) {
 988                                         struct btrfs_header *const next_hdr =
 989                                             (struct btrfs_header *)
 990                                             sf->next_block_ctx.datav[0];
 991
 992                                         next_stack =
 993                                             btrfsic_stack_frame_alloc();
 994                                         if (NULL == next_stack) {
 995                                                 sf->error = -1;
 996                                                 btrfsic_release_block_ctx(
 997                                                                 &sf->
 998                                                                 next_block_ctx);
 999                                                 goto one_stack_frame_backwards;
1000                                         }
1001
1002                                         next_stack->i = -1;
1003                                         next_stack->block = sf->next_block;
1004                                         next_stack->block_ctx =
1005                                             &sf->next_block_ctx;
1006                                         next_stack->next_block = NULL;
1007                                         next_stack->hdr = next_hdr;
1008                                         next_stack->limit_nesting =
1009                                             sf->limit_nesting - 1;
1010                                         next_stack->prev = sf;
1011                                         sf = next_stack;
1012                                         goto continue_with_new_stack_frame;
1013                                 }
1014                         } else if (BTRFS_EXTENT_DATA_KEY == type &&
1015                                    state->include_extent_data) {
1016                                 sf->error = btrfsic_handle_extent_data(
1017                                                 state,
1018                                                 sf->block,
1019                                                 sf->block_ctx,
1020                                                 item_offset,
1021                                                 force_iodone_flag);
1022                                 if (sf->error)
1023                                         goto one_stack_frame_backwards;
1024                         }
1025
1026                         goto continue_with_current_leaf_stack_frame;
1027                 }
1028         } else {
1029                 struct btrfs_node *const nodehdr = (struct btrfs_node *)sf->hdr;
1030
1031                 if (-1 == sf->i) {
1032                         sf->nr = btrfs_stack_header_nritems(&nodehdr->header);
1033
1034                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1035                                 pr_info("node %llu level %d items %d generation %llu owner %llu\n",
1036                                        sf->block_ctx->start,
1037                                        nodehdr->header.level, sf->nr,
1038                                        btrfs_stack_header_generation(
1039                                        &nodehdr->header),
1040                                        btrfs_stack_header_owner(
1041                                        &nodehdr->header));
1042                 }
1043
1044 continue_with_current_node_stack_frame:
1045                 if (0 == sf->num_copies || sf->mirror_num > sf->num_copies) {
1046                         sf->i++;
1047                         sf->num_copies = 0;
1048                 }
1049
1050                 if (sf->i < sf->nr) {
1051                         struct btrfs_key_ptr key_ptr;
1052                         u32 key_ptr_offset;
1053                         u64 next_bytenr;
1054
1055                         key_ptr_offset = (uintptr_t)(nodehdr->ptrs + sf->i) -
1056                                           (uintptr_t)nodehdr;
1057                         if (key_ptr_offset + sizeof(struct btrfs_key_ptr) >
1058                             sf->block_ctx->len) {
1059                                 pr_info(
1060                 "btrfsic: node item out of bounce at logical %llu, dev %pg\n",
1061                                        sf->block_ctx->start,
1062                                        sf->block_ctx->dev->bdev);
1063                                 goto one_stack_frame_backwards;
1064                         }
1065                         btrfsic_read_from_block_data(
1066                                 sf->block_ctx, &key_ptr, key_ptr_offset,
1067                                 sizeof(struct btrfs_key_ptr));
1068                         next_bytenr = btrfs_stack_key_blockptr(&key_ptr);
1069
1070                         sf->error = btrfsic_create_link_to_next_block(
1071                                         state,
1072                                         sf->block,
1073                                         sf->block_ctx,
1074                                         next_bytenr,
1075                                         sf->limit_nesting,
1076                                         &sf->next_block_ctx,
1077                                         &sf->next_block,
1078                                         force_iodone_flag,
1079                                         &sf->num_copies,
1080                                         &sf->mirror_num,
1081                                         &key_ptr.key,
1082                                         btrfs_stack_key_generation(&key_ptr));
1083                         if (sf->error)
1084                                 goto one_stack_frame_backwards;
1085
1086                         if (NULL != sf->next_block) {
1087                                 struct btrfs_header *const next_hdr =
1088                                     (struct btrfs_header *)
1089                                     sf->next_block_ctx.datav[0];
1090
1091                                 next_stack = btrfsic_stack_frame_alloc();
1092                                 if (NULL == next_stack) {
1093                                         sf->error = -1;
1094                                         goto one_stack_frame_backwards;
1095                                 }
1096
1097                                 next_stack->i = -1;
1098                                 next_stack->block = sf->next_block;
1099                                 next_stack->block_ctx = &sf->next_block_ctx;
1100                                 next_stack->next_block = NULL;
1101                                 next_stack->hdr = next_hdr;
1102                                 next_stack->limit_nesting =
1103                                     sf->limit_nesting - 1;
1104                                 next_stack->prev = sf;
1105                                 sf = next_stack;
1106                                 goto continue_with_new_stack_frame;
1107                         }
1108
1109                         goto continue_with_current_node_stack_frame;
1110                 }
1111         }
1112
1113 one_stack_frame_backwards:
1114         if (NULL != sf->prev) {
1115                 struct btrfsic_stack_frame *const prev = sf->prev;
1116
1117                 /* the one for the initial block is freed in the caller */
1118                 btrfsic_release_block_ctx(sf->block_ctx);
1119
1120                 if (sf->error) {
1121                         prev->error = sf->error;
1122                         btrfsic_stack_frame_free(sf);
1123                         sf = prev;
1124                         goto one_stack_frame_backwards;
1125                 }
1126
1127                 btrfsic_stack_frame_free(sf);
1128                 sf = prev;
1129                 goto continue_with_new_stack_frame;
1130         } else {
1131                 BUG_ON(&initial_stack_frame != sf);
1132         }
1133
1134         return sf->error;
1135 }
1136
1137 static void btrfsic_read_from_block_data(
1138         struct btrfsic_block_data_ctx *block_ctx,
1139         void *dstv, u32 offset, size_t len)
1140 {
1141         size_t cur;
1142         size_t pgoff;
1143         char *kaddr;
1144         char *dst = (char *)dstv;
1145         size_t start_offset = offset_in_page(block_ctx->start);
1146         unsigned long i = (start_offset + offset) >> PAGE_SHIFT;
1147
1148         WARN_ON(offset + len > block_ctx->len);
1149         pgoff = offset_in_page(start_offset + offset);
1150
1151         while (len > 0) {
1152                 cur = min(len, ((size_t)PAGE_SIZE - pgoff));
1153                 BUG_ON(i >= DIV_ROUND_UP(block_ctx->len, PAGE_SIZE));
1154                 kaddr = block_ctx->datav[i];
1155                 memcpy(dst, kaddr + pgoff, cur);
1156
1157                 dst += cur;
1158                 len -= cur;
1159                 pgoff = 0;
1160                 i++;
1161         }
1162 }
1163
1164 static int btrfsic_create_link_to_next_block(
1165                 struct btrfsic_state *state,
1166                 struct btrfsic_block *block,
1167                 struct btrfsic_block_data_ctx *block_ctx,
1168                 u64 next_bytenr,
1169                 int limit_nesting,
1170                 struct btrfsic_block_data_ctx *next_block_ctx,
1171                 struct btrfsic_block **next_blockp,
1172                 int force_iodone_flag,
1173                 int *num_copiesp, int *mirror_nump,
1174                 struct btrfs_disk_key *disk_key,
1175                 u64 parent_generation)
1176 {
1177         struct btrfs_fs_info *fs_info = state->fs_info;
1178         struct btrfsic_block *next_block = NULL;
1179         int ret;
1180         struct btrfsic_block_link *l;
1181         int did_alloc_block_link;
1182         int block_was_created;
1183
1184         *next_blockp = NULL;
1185         if (0 == *num_copiesp) {
1186                 *num_copiesp = btrfs_num_copies(fs_info, next_bytenr,
1187                                                 state->metablock_size);
1188                 if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
1189                         pr_info("num_copies(log_bytenr=%llu) = %d\n",
1190                                next_bytenr, *num_copiesp);
1191                 *mirror_nump = 1;
1192         }
1193
1194         if (*mirror_nump > *num_copiesp)
1195                 return 0;
1196
1197         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1198                 pr_info("btrfsic_create_link_to_next_block(mirror_num=%d)\n",
1199                        *mirror_nump);
1200         ret = btrfsic_map_block(state, next_bytenr,
1201                                 state->metablock_size,
1202                                 next_block_ctx, *mirror_nump);
1203         if (ret) {
1204                 pr_info("btrfsic: btrfsic_map_block(@%llu, mirror=%d) failed!\n",
1205                        next_bytenr, *mirror_nump);
1206                 btrfsic_release_block_ctx(next_block_ctx);
1207                 *next_blockp = NULL;
1208                 return -1;
1209         }
1210
1211         next_block = btrfsic_block_lookup_or_add(state,
1212                                                  next_block_ctx, "referenced ",
1213                                                  1, force_iodone_flag,
1214                                                  !force_iodone_flag,
1215                                                  *mirror_nump,
1216                                                  &block_was_created);
1217         if (NULL == next_block) {
1218                 btrfsic_release_block_ctx(next_block_ctx);
1219                 *next_blockp = NULL;
1220                 return -1;
1221         }
1222         if (block_was_created) {
1223                 l = NULL;
1224                 next_block->generation = BTRFSIC_GENERATION_UNKNOWN;
1225         } else {
1226                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE) {
1227                         if (next_block->logical_bytenr != next_bytenr &&
1228                             !(!next_block->is_metadata &&
1229                               0 == next_block->logical_bytenr))
1230                                 pr_info(
1231 "referenced block @%llu (%pg/%llu/%d) found in hash table, %c, bytenr mismatch (!= stored %llu)\n",
1232                                        next_bytenr, next_block_ctx->dev->bdev,
1233                                        next_block_ctx->dev_bytenr, *mirror_nump,
1234                                        btrfsic_get_block_type(state,
1235                                                               next_block),
1236                                        next_block->logical_bytenr);
1237                         else
1238                                 pr_info(
1239                 "referenced block @%llu (%pg/%llu/%d) found in hash table, %c\n",
1240                                        next_bytenr, next_block_ctx->dev->bdev,
1241                                        next_block_ctx->dev_bytenr, *mirror_nump,
1242                                        btrfsic_get_block_type(state,
1243                                                               next_block));
1244                 }
1245                 next_block->logical_bytenr = next_bytenr;
1246
1247                 next_block->mirror_num = *mirror_nump;
1248                 l = btrfsic_block_link_hashtable_lookup(
1249                                 next_block_ctx->dev->bdev,
1250                                 next_block_ctx->dev_bytenr,
1251                                 block_ctx->dev->bdev,
1252                                 block_ctx->dev_bytenr,
1253                                 &state->block_link_hashtable);
1254         }
1255
1256         next_block->disk_key = *disk_key;
1257         if (NULL == l) {
1258                 l = btrfsic_block_link_alloc();
1259                 if (NULL == l) {
1260                         btrfsic_release_block_ctx(next_block_ctx);
1261                         *next_blockp = NULL;
1262                         return -1;
1263                 }
1264
1265                 did_alloc_block_link = 1;
1266                 l->block_ref_to = next_block;
1267                 l->block_ref_from = block;
1268                 l->ref_cnt = 1;
1269                 l->parent_generation = parent_generation;
1270
1271                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1272                         btrfsic_print_add_link(state, l);
1273
1274                 list_add(&l->node_ref_to, &block->ref_to_list);
1275                 list_add(&l->node_ref_from, &next_block->ref_from_list);
1276
1277                 btrfsic_block_link_hashtable_add(l,
1278                                                  &state->block_link_hashtable);
1279         } else {
1280                 did_alloc_block_link = 0;
1281                 if (0 == limit_nesting) {
1282                         l->ref_cnt++;
1283                         l->parent_generation = parent_generation;
1284                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1285                                 btrfsic_print_add_link(state, l);
1286                 }
1287         }
1288
1289         if (limit_nesting > 0 && did_alloc_block_link) {
1290                 ret = btrfsic_read_block(state, next_block_ctx);
1291                 if (ret < (int)next_block_ctx->len) {
1292                         pr_info("btrfsic: read block @logical %llu failed!\n",
1293                                next_bytenr);
1294                         btrfsic_release_block_ctx(next_block_ctx);
1295                         *next_blockp = NULL;
1296                         return -1;
1297                 }
1298
1299                 *next_blockp = next_block;
1300         } else {
1301                 *next_blockp = NULL;
1302         }
1303         (*mirror_nump)++;
1304
1305         return 0;
1306 }
1307
1308 static int btrfsic_handle_extent_data(
1309                 struct btrfsic_state *state,
1310                 struct btrfsic_block *block,
1311                 struct btrfsic_block_data_ctx *block_ctx,
1312                 u32 item_offset, int force_iodone_flag)
1313 {
1314         struct btrfs_fs_info *fs_info = state->fs_info;
1315         struct btrfs_file_extent_item file_extent_item;
1316         u64 file_extent_item_offset;
1317         u64 next_bytenr;
1318         u64 num_bytes;
1319         u64 generation;
1320         struct btrfsic_block_link *l;
1321         int ret;
1322
1323         file_extent_item_offset = offsetof(struct btrfs_leaf, items) +
1324                                   item_offset;
1325         if (file_extent_item_offset +
1326             offsetof(struct btrfs_file_extent_item, disk_num_bytes) >
1327             block_ctx->len) {
1328                 pr_info("btrfsic: file item out of bounce at logical %llu, dev %pg\n",
1329                        block_ctx->start, block_ctx->dev->bdev);
1330                 return -1;
1331         }
1332
1333         btrfsic_read_from_block_data(block_ctx, &file_extent_item,
1334                 file_extent_item_offset,
1335                 offsetof(struct btrfs_file_extent_item, disk_num_bytes));
1336         if (BTRFS_FILE_EXTENT_REG != file_extent_item.type ||
1337             btrfs_stack_file_extent_disk_bytenr(&file_extent_item) == 0) {
1338                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERY_VERBOSE)
1339                         pr_info("extent_data: type %u, disk_bytenr = %llu\n",
1340                                file_extent_item.type,
1341                                btrfs_stack_file_extent_disk_bytenr(
1342                                &file_extent_item));
1343                 return 0;
1344         }
1345
1346         if (file_extent_item_offset + sizeof(struct btrfs_file_extent_item) >
1347             block_ctx->len) {
1348                 pr_info("btrfsic: file item out of bounce at logical %llu, dev %pg\n",
1349                        block_ctx->start, block_ctx->dev->bdev);
1350                 return -1;
1351         }
1352         btrfsic_read_from_block_data(block_ctx, &file_extent_item,
1353                                      file_extent_item_offset,
1354                                      sizeof(struct btrfs_file_extent_item));
1355         next_bytenr = btrfs_stack_file_extent_disk_bytenr(&file_extent_item);
1356         if (btrfs_stack_file_extent_compression(&file_extent_item) ==
1357             BTRFS_COMPRESS_NONE) {
1358                 next_bytenr += btrfs_stack_file_extent_offset(&file_extent_item);
1359                 num_bytes = btrfs_stack_file_extent_num_bytes(&file_extent_item);
1360         } else {
1361                 num_bytes = btrfs_stack_file_extent_disk_num_bytes(&file_extent_item);
1362         }
1363         generation = btrfs_stack_file_extent_generation(&file_extent_item);
1364
1365         if (state->print_mask & BTRFSIC_PRINT_MASK_VERY_VERBOSE)
1366                 pr_info("extent_data: type %u, disk_bytenr = %llu, offset = %llu, num_bytes = %llu\n",
1367                        file_extent_item.type,
1368                        btrfs_stack_file_extent_disk_bytenr(&file_extent_item),
1369                        btrfs_stack_file_extent_offset(&file_extent_item),
1370                        num_bytes);
1371         while (num_bytes > 0) {
1372                 u32 chunk_len;
1373                 int num_copies;
1374                 int mirror_num;
1375
1376                 if (num_bytes > state->datablock_size)
1377                         chunk_len = state->datablock_size;
1378                 else
1379                         chunk_len = num_bytes;
1380
1381                 num_copies = btrfs_num_copies(fs_info, next_bytenr,
1382                                               state->datablock_size);
1383                 if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
1384                         pr_info("num_copies(log_bytenr=%llu) = %d\n",
1385                                next_bytenr, num_copies);
1386                 for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
1387                         struct btrfsic_block_data_ctx next_block_ctx;
1388                         struct btrfsic_block *next_block;
1389                         int block_was_created;
1390
1391                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1392                                 pr_info("btrfsic_handle_extent_data(mirror_num=%d)\n",
1393                                         mirror_num);
1394                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERY_VERBOSE)
1395                                 pr_info("\tdisk_bytenr = %llu, num_bytes %u\n",
1396                                        next_bytenr, chunk_len);
1397                         ret = btrfsic_map_block(state, next_bytenr,
1398                                                 chunk_len, &next_block_ctx,
1399                                                 mirror_num);
1400                         if (ret) {
1401                                 pr_info("btrfsic: btrfsic_map_block(@%llu, mirror=%d) failed!\n",
1402                                        next_bytenr, mirror_num);
1403                                 return -1;
1404                         }
1405
1406                         next_block = btrfsic_block_lookup_or_add(
1407                                         state,
1408                                         &next_block_ctx,
1409                                         "referenced ",
1410                                         0,
1411                                         force_iodone_flag,
1412                                         !force_iodone_flag,
1413                                         mirror_num,
1414                                         &block_was_created);
1415                         if (NULL == next_block) {
1416                                 btrfsic_release_block_ctx(&next_block_ctx);
1417                                 return -1;
1418                         }
1419                         if (!block_was_created) {
1420                                 if ((state->print_mask &
1421                                      BTRFSIC_PRINT_MASK_VERBOSE) &&
1422                                     next_block->logical_bytenr != next_bytenr &&
1423                                     !(!next_block->is_metadata &&
1424                                       0 == next_block->logical_bytenr)) {
1425                                         pr_info(
1426 "referenced block @%llu (%pg/%llu/%d) found in hash table, D, bytenr mismatch (!= stored %llu)\n",
1427                                                next_bytenr,
1428                                                next_block_ctx.dev->bdev,
1429                                                next_block_ctx.dev_bytenr,
1430                                                mirror_num,
1431                                                next_block->logical_bytenr);
1432                                 }
1433                                 next_block->logical_bytenr = next_bytenr;
1434                                 next_block->mirror_num = mirror_num;
1435                         }
1436
1437                         l = btrfsic_block_link_lookup_or_add(state,
1438                                                              &next_block_ctx,
1439                                                              next_block, block,
1440                                                              generation);
1441                         btrfsic_release_block_ctx(&next_block_ctx);
1442                         if (NULL == l)
1443                                 return -1;
1444                 }
1445
1446                 next_bytenr += chunk_len;
1447                 num_bytes -= chunk_len;
1448         }
1449
1450         return 0;
1451 }
1452
1453 static int btrfsic_map_block(struct btrfsic_state *state, u64 bytenr, u32 len,
1454                              struct btrfsic_block_data_ctx *block_ctx_out,
1455                              int mirror_num)
1456 {
1457         struct btrfs_fs_info *fs_info = state->fs_info;
1458         int ret;
1459         u64 length;
1460         struct btrfs_io_context *multi = NULL;
1461         struct btrfs_device *device;
1462
1463         length = len;
1464         ret = btrfs_map_block(fs_info, BTRFS_MAP_READ,
1465                               bytenr, &length, &multi, mirror_num);
1466
1467         if (ret) {
1468                 block_ctx_out->start = 0;
1469                 block_ctx_out->dev_bytenr = 0;
1470                 block_ctx_out->len = 0;
1471                 block_ctx_out->dev = NULL;
1472                 block_ctx_out->datav = NULL;
1473                 block_ctx_out->pagev = NULL;
1474                 block_ctx_out->mem_to_free = NULL;
1475
1476                 return ret;
1477         }
1478
1479         device = multi->stripes[0].dev;
1480         if (test_bit(BTRFS_DEV_STATE_MISSING, &device->dev_state) ||
1481             !device->bdev || !device->name)
1482                 block_ctx_out->dev = NULL;
1483         else
1484                 block_ctx_out->dev = btrfsic_dev_state_lookup(
1485                                                         device->bdev->bd_dev);
1486         block_ctx_out->dev_bytenr = multi->stripes[0].physical;
1487         block_ctx_out->start = bytenr;
1488         block_ctx_out->len = len;
1489         block_ctx_out->datav = NULL;
1490         block_ctx_out->pagev = NULL;
1491         block_ctx_out->mem_to_free = NULL;
1492
1493         kfree(multi);
1494         if (NULL == block_ctx_out->dev) {
1495                 ret = -ENXIO;
1496                 pr_info("btrfsic: error, cannot lookup dev (#1)!\n");
1497         }
1498
1499         return ret;
1500 }
1501
1502 static void btrfsic_release_block_ctx(struct btrfsic_block_data_ctx *block_ctx)
1503 {
1504         if (block_ctx->mem_to_free) {
1505                 unsigned int num_pages;
1506
1507                 BUG_ON(!block_ctx->datav);
1508                 BUG_ON(!block_ctx->pagev);
1509                 num_pages = (block_ctx->len + (u64)PAGE_SIZE - 1) >>
1510                             PAGE_SHIFT;
1511                 /* Pages must be unmapped in reverse order */
1512                 while (num_pages > 0) {
1513                         num_pages--;
1514                         if (block_ctx->datav[num_pages])
1515                                 block_ctx->datav[num_pages] = NULL;
1516                         if (block_ctx->pagev[num_pages]) {
1517                                 __free_page(block_ctx->pagev[num_pages]);
1518                                 block_ctx->pagev[num_pages] = NULL;
1519                         }
1520                 }
1521
1522                 kfree(block_ctx->mem_to_free);
1523                 block_ctx->mem_to_free = NULL;
1524                 block_ctx->pagev = NULL;
1525                 block_ctx->datav = NULL;
1526         }
1527 }
1528
1529 static int btrfsic_read_block(struct btrfsic_state *state,
1530                               struct btrfsic_block_data_ctx *block_ctx)
1531 {
1532         unsigned int num_pages;
1533         unsigned int i;
1534         size_t size;
1535         u64 dev_bytenr;
1536         int ret;
1537
1538         BUG_ON(block_ctx->datav);
1539         BUG_ON(block_ctx->pagev);
1540         BUG_ON(block_ctx->mem_to_free);
1541         if (!PAGE_ALIGNED(block_ctx->dev_bytenr)) {
1542                 pr_info("btrfsic: read_block() with unaligned bytenr %llu\n",
1543                        block_ctx->dev_bytenr);
1544                 return -1;
1545         }
1546
1547         num_pages = (block_ctx->len + (u64)PAGE_SIZE - 1) >>
1548                     PAGE_SHIFT;
1549         size = sizeof(*block_ctx->datav) + sizeof(*block_ctx->pagev);
1550         block_ctx->mem_to_free = kcalloc(num_pages, size, GFP_NOFS);
1551         if (!block_ctx->mem_to_free)
1552                 return -ENOMEM;
1553         block_ctx->datav = block_ctx->mem_to_free;
1554         block_ctx->pagev = (struct page **)(block_ctx->datav + num_pages);
1555         ret = btrfs_alloc_page_array(num_pages, block_ctx->pagev);
1556         if (ret)
1557                 return ret;
1558
1559         dev_bytenr = block_ctx->dev_bytenr;
1560         for (i = 0; i < num_pages;) {
1561                 struct bio *bio;
1562                 unsigned int j;
1563
1564                 bio = bio_alloc(block_ctx->dev->bdev, num_pages - i,
1565                                 REQ_OP_READ, GFP_NOFS);
1566                 bio->bi_iter.bi_sector = dev_bytenr >> 9;
1567
1568                 for (j = i; j < num_pages; j++) {
1569                         ret = bio_add_page(bio, block_ctx->pagev[j],
1570                                            PAGE_SIZE, 0);
1571                         if (PAGE_SIZE != ret)
1572                                 break;
1573                 }
1574                 if (j == i) {
1575                         pr_info("btrfsic: error, failed to add a single page!\n");
1576                         return -1;
1577                 }
1578                 if (submit_bio_wait(bio)) {
1579                         pr_info("btrfsic: read error at logical %llu dev %pg!\n",
1580                                block_ctx->start, block_ctx->dev->bdev);
1581                         bio_put(bio);
1582                         return -1;
1583                 }
1584                 bio_put(bio);
1585                 dev_bytenr += (j - i) * PAGE_SIZE;
1586                 i = j;
1587         }
1588         for (i = 0; i < num_pages; i++)
1589                 block_ctx->datav[i] = page_address(block_ctx->pagev[i]);
1590
1591         return block_ctx->len;
1592 }
1593
1594 static void btrfsic_dump_database(struct btrfsic_state *state)
1595 {
1596         const struct btrfsic_block *b_all;
1597
1598         BUG_ON(NULL == state);
1599
1600         pr_info("all_blocks_list:\n");
1601         list_for_each_entry(b_all, &state->all_blocks_list, all_blocks_node) {
1602                 const struct btrfsic_block_link *l;
1603
1604                 pr_info("%c-block @%llu (%pg/%llu/%d)\n",
1605                        btrfsic_get_block_type(state, b_all),
1606                        b_all->logical_bytenr, b_all->dev_state->bdev,
1607                        b_all->dev_bytenr, b_all->mirror_num);
1608
1609                 list_for_each_entry(l, &b_all->ref_to_list, node_ref_to) {
1610                         pr_info(
1611                 " %c @%llu (%pg/%llu/%d) refers %u* to %c @%llu (%pg/%llu/%d)\n",
1612                                btrfsic_get_block_type(state, b_all),
1613                                b_all->logical_bytenr, b_all->dev_state->bdev,
1614                                b_all->dev_bytenr, b_all->mirror_num,
1615                                l->ref_cnt,
1616                                btrfsic_get_block_type(state, l->block_ref_to),
1617                                l->block_ref_to->logical_bytenr,
1618                                l->block_ref_to->dev_state->bdev,
1619                                l->block_ref_to->dev_bytenr,
1620                                l->block_ref_to->mirror_num);
1621                 }
1622
1623                 list_for_each_entry(l, &b_all->ref_from_list, node_ref_from) {
1624                         pr_info(
1625                 " %c @%llu (%pg/%llu/%d) is ref %u* from %c @%llu (%pg/%llu/%d)\n",
1626                                btrfsic_get_block_type(state, b_all),
1627                                b_all->logical_bytenr, b_all->dev_state->bdev,
1628                                b_all->dev_bytenr, b_all->mirror_num,
1629                                l->ref_cnt,
1630                                btrfsic_get_block_type(state, l->block_ref_from),
1631                                l->block_ref_from->logical_bytenr,
1632                                l->block_ref_from->dev_state->bdev,
1633                                l->block_ref_from->dev_bytenr,
1634                                l->block_ref_from->mirror_num);
1635                 }
1636
1637                 pr_info("\n");
1638         }
1639 }
1640
1641 /*
1642  * Test whether the disk block contains a tree block (leaf or node)
1643  * (note that this test fails for the super block)
1644  */
1645 static noinline_for_stack int btrfsic_test_for_metadata(
1646                 struct btrfsic_state *state,
1647                 char **datav, unsigned int num_pages)
1648 {
1649         struct btrfs_fs_info *fs_info = state->fs_info;
1650         SHASH_DESC_ON_STACK(shash, fs_info->csum_shash);
1651         struct btrfs_header *h;
1652         u8 csum[BTRFS_CSUM_SIZE];
1653         unsigned int i;
1654
1655         if (num_pages * PAGE_SIZE < state->metablock_size)
1656                 return 1; /* not metadata */
1657         num_pages = state->metablock_size >> PAGE_SHIFT;
1658         h = (struct btrfs_header *)datav[0];
1659
1660         if (memcmp(h->fsid, fs_info->fs_devices->fsid, BTRFS_FSID_SIZE))
1661                 return 1;
1662
1663         shash->tfm = fs_info->csum_shash;
1664         crypto_shash_init(shash);
1665
1666         for (i = 0; i < num_pages; i++) {
1667                 u8 *data = i ? datav[i] : (datav[i] + BTRFS_CSUM_SIZE);
1668                 size_t sublen = i ? PAGE_SIZE :
1669                                     (PAGE_SIZE - BTRFS_CSUM_SIZE);
1670
1671                 crypto_shash_update(shash, data, sublen);
1672         }
1673         crypto_shash_final(shash, csum);
1674         if (memcmp(csum, h->csum, fs_info->csum_size))
1675                 return 1;
1676
1677         return 0; /* is metadata */
1678 }
1679
1680 static void btrfsic_process_written_block(struct btrfsic_dev_state *dev_state,
1681                                           u64 dev_bytenr, char **mapped_datav,
1682                                           unsigned int num_pages,
1683                                           struct bio *bio, int *bio_is_patched,
1684                                           blk_opf_t submit_bio_bh_rw)
1685 {
1686         int is_metadata;
1687         struct btrfsic_block *block;
1688         struct btrfsic_block_data_ctx block_ctx;
1689         int ret;
1690         struct btrfsic_state *state = dev_state->state;
1691         struct block_device *bdev = dev_state->bdev;
1692         unsigned int processed_len;
1693
1694         if (NULL != bio_is_patched)
1695                 *bio_is_patched = 0;
1696
1697 again:
1698         if (num_pages == 0)
1699                 return;
1700
1701         processed_len = 0;
1702         is_metadata = (0 == btrfsic_test_for_metadata(state, mapped_datav,
1703                                                       num_pages));
1704
1705         block = btrfsic_block_hashtable_lookup(bdev, dev_bytenr,
1706                                                &state->block_hashtable);
1707         if (NULL != block) {
1708                 u64 bytenr = 0;
1709                 struct btrfsic_block_link *l, *tmp;
1710
1711                 if (block->is_superblock) {
1712                         bytenr = btrfs_super_bytenr((struct btrfs_super_block *)
1713                                                     mapped_datav[0]);
1714                         if (num_pages * PAGE_SIZE <
1715                             BTRFS_SUPER_INFO_SIZE) {
1716                                 pr_info("btrfsic: cannot work with too short bios!\n");
1717                                 return;
1718                         }
1719                         is_metadata = 1;
1720                         BUG_ON(!PAGE_ALIGNED(BTRFS_SUPER_INFO_SIZE));
1721                         processed_len = BTRFS_SUPER_INFO_SIZE;
1722                         if (state->print_mask &
1723                             BTRFSIC_PRINT_MASK_TREE_BEFORE_SB_WRITE) {
1724                                 pr_info("[before new superblock is written]:\n");
1725                                 btrfsic_dump_tree_sub(state, block, 0);
1726                         }
1727                 }
1728                 if (is_metadata) {
1729                         if (!block->is_superblock) {
1730                                 if (num_pages * PAGE_SIZE <
1731                                     state->metablock_size) {
1732                                         pr_info("btrfsic: cannot work with too short bios!\n");
1733                                         return;
1734                                 }
1735                                 processed_len = state->metablock_size;
1736                                 bytenr = btrfs_stack_header_bytenr(
1737                                                 (struct btrfs_header *)
1738                                                 mapped_datav[0]);
1739                                 btrfsic_cmp_log_and_dev_bytenr(state, bytenr,
1740                                                                dev_state,
1741                                                                dev_bytenr);
1742                         }
1743                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE) {
1744                                 if (block->logical_bytenr != bytenr &&
1745                                     !(!block->is_metadata &&
1746                                       block->logical_bytenr == 0))
1747                                         pr_info(
1748 "written block @%llu (%pg/%llu/%d) found in hash table, %c, bytenr mismatch (!= stored %llu)\n",
1749                                                bytenr, dev_state->bdev,
1750                                                dev_bytenr,
1751                                                block->mirror_num,
1752                                                btrfsic_get_block_type(state,
1753                                                                       block),
1754                                                block->logical_bytenr);
1755                                 else
1756                                         pr_info(
1757                 "written block @%llu (%pg/%llu/%d) found in hash table, %c\n",
1758                                                bytenr, dev_state->bdev,
1759                                                dev_bytenr, block->mirror_num,
1760                                                btrfsic_get_block_type(state,
1761                                                                       block));
1762                         }
1763                         block->logical_bytenr = bytenr;
1764                 } else {
1765                         if (num_pages * PAGE_SIZE <
1766                             state->datablock_size) {
1767                                 pr_info("btrfsic: cannot work with too short bios!\n");
1768                                 return;
1769                         }
1770                         processed_len = state->datablock_size;
1771                         bytenr = block->logical_bytenr;
1772                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1773                                 pr_info(
1774                 "written block @%llu (%pg/%llu/%d) found in hash table, %c\n",
1775                                        bytenr, dev_state->bdev, dev_bytenr,
1776                                        block->mirror_num,
1777                                        btrfsic_get_block_type(state, block));
1778                 }
1779
1780                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1781                         pr_info("ref_to_list: %cE, ref_from_list: %cE\n",
1782                                list_empty(&block->ref_to_list) ? ' ' : '!',
1783                                list_empty(&block->ref_from_list) ? ' ' : '!');
1784                 if (btrfsic_is_block_ref_by_superblock(state, block, 0)) {
1785                         pr_info(
1786 "btrfs: attempt to overwrite %c-block @%llu (%pg/%llu/%d), old(gen=%llu, objectid=%llu, type=%d, offset=%llu), new(gen=%llu), which is referenced by most recent superblock (superblockgen=%llu)!\n",
1787                                btrfsic_get_block_type(state, block), bytenr,
1788                                dev_state->bdev, dev_bytenr, block->mirror_num,
1789                                block->generation,
1790                                btrfs_disk_key_objectid(&block->disk_key),
1791                                block->disk_key.type,
1792                                btrfs_disk_key_offset(&block->disk_key),
1793                                btrfs_stack_header_generation(
1794                                        (struct btrfs_header *) mapped_datav[0]),
1795                                state->max_superblock_generation);
1796                         btrfsic_dump_tree(state);
1797                 }
1798
1799                 if (!block->is_iodone && !block->never_written) {
1800                         pr_info(
1801 "btrfs: attempt to overwrite %c-block @%llu (%pg/%llu/%d), oldgen=%llu, newgen=%llu, which is not yet iodone!\n",
1802                                btrfsic_get_block_type(state, block), bytenr,
1803                                dev_state->bdev, dev_bytenr, block->mirror_num,
1804                                block->generation,
1805                                btrfs_stack_header_generation(
1806                                        (struct btrfs_header *)
1807                                        mapped_datav[0]));
1808                         /* it would not be safe to go on */
1809                         btrfsic_dump_tree(state);
1810                         goto continue_loop;
1811                 }
1812
1813                 /*
1814                  * Clear all references of this block. Do not free
1815                  * the block itself even if is not referenced anymore
1816                  * because it still carries valuable information
1817                  * like whether it was ever written and IO completed.
1818                  */
1819                 list_for_each_entry_safe(l, tmp, &block->ref_to_list,
1820                                          node_ref_to) {
1821                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1822                                 btrfsic_print_rem_link(state, l);
1823                         l->ref_cnt--;
1824                         if (0 == l->ref_cnt) {
1825                                 list_del(&l->node_ref_to);
1826                                 list_del(&l->node_ref_from);
1827                                 btrfsic_block_link_hashtable_remove(l);
1828                                 btrfsic_block_link_free(l);
1829                         }
1830                 }
1831
1832                 block_ctx.dev = dev_state;
1833                 block_ctx.dev_bytenr = dev_bytenr;
1834                 block_ctx.start = bytenr;
1835                 block_ctx.len = processed_len;
1836                 block_ctx.pagev = NULL;
1837                 block_ctx.mem_to_free = NULL;
1838                 block_ctx.datav = mapped_datav;
1839
1840                 if (is_metadata || state->include_extent_data) {
1841                         block->never_written = 0;
1842                         block->iodone_w_error = 0;
1843                         if (NULL != bio) {
1844                                 block->is_iodone = 0;
1845                                 BUG_ON(NULL == bio_is_patched);
1846                                 if (!*bio_is_patched) {
1847                                         block->orig_bio_private =
1848                                             bio->bi_private;
1849                                         block->orig_bio_end_io =
1850                                             bio->bi_end_io;
1851                                         block->next_in_same_bio = NULL;
1852                                         bio->bi_private = block;
1853                                         bio->bi_end_io = btrfsic_bio_end_io;
1854                                         *bio_is_patched = 1;
1855                                 } else {
1856                                         struct btrfsic_block *chained_block =
1857                                             (struct btrfsic_block *)
1858                                             bio->bi_private;
1859
1860                                         BUG_ON(NULL == chained_block);
1861                                         block->orig_bio_private =
1862                                             chained_block->orig_bio_private;
1863                                         block->orig_bio_end_io =
1864                                             chained_block->orig_bio_end_io;
1865                                         block->next_in_same_bio = chained_block;
1866                                         bio->bi_private = block;
1867                                 }
1868                         } else {
1869                                 block->is_iodone = 1;
1870                                 block->orig_bio_private = NULL;
1871                                 block->orig_bio_end_io = NULL;
1872                                 block->next_in_same_bio = NULL;
1873                         }
1874                 }
1875
1876                 block->flush_gen = dev_state->last_flush_gen + 1;
1877                 block->submit_bio_bh_rw = submit_bio_bh_rw;
1878                 if (is_metadata) {
1879                         block->logical_bytenr = bytenr;
1880                         block->is_metadata = 1;
1881                         if (block->is_superblock) {
1882                                 BUG_ON(PAGE_SIZE !=
1883                                        BTRFS_SUPER_INFO_SIZE);
1884                                 ret = btrfsic_process_written_superblock(
1885                                                 state,
1886                                                 block,
1887                                                 (struct btrfs_super_block *)
1888                                                 mapped_datav[0]);
1889                                 if (state->print_mask &
1890                                     BTRFSIC_PRINT_MASK_TREE_AFTER_SB_WRITE) {
1891                                         pr_info("[after new superblock is written]:\n");
1892                                         btrfsic_dump_tree_sub(state, block, 0);
1893                                 }
1894                         } else {
1895                                 block->mirror_num = 0;  /* unknown */
1896                                 ret = btrfsic_process_metablock(
1897                                                 state,
1898                                                 block,
1899                                                 &block_ctx,
1900                                                 0, 0);
1901                         }
1902                         if (ret)
1903                                 pr_info("btrfsic: btrfsic_process_metablock(root @%llu) failed!\n",
1904                                        dev_bytenr);
1905                 } else {
1906                         block->is_metadata = 0;
1907                         block->mirror_num = 0;  /* unknown */
1908                         block->generation = BTRFSIC_GENERATION_UNKNOWN;
1909                         if (!state->include_extent_data
1910                             && list_empty(&block->ref_from_list)) {
1911                                 /*
1912                                  * disk block is overwritten with extent
1913                                  * data (not meta data) and we are configured
1914                                  * to not include extent data: take the
1915                                  * chance and free the block's memory
1916                                  */
1917                                 btrfsic_block_hashtable_remove(block);
1918                                 list_del(&block->all_blocks_node);
1919                                 btrfsic_block_free(block);
1920                         }
1921                 }
1922                 btrfsic_release_block_ctx(&block_ctx);
1923         } else {
1924                 /* block has not been found in hash table */
1925                 u64 bytenr;
1926
1927                 if (!is_metadata) {
1928                         processed_len = state->datablock_size;
1929                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1930                                 pr_info(
1931                         "written block (%pg/%llu/?) !found in hash table, D\n",
1932                                        dev_state->bdev, dev_bytenr);
1933                         if (!state->include_extent_data) {
1934                                 /* ignore that written D block */
1935                                 goto continue_loop;
1936                         }
1937
1938                         /* this is getting ugly for the
1939                          * include_extent_data case... */
1940                         bytenr = 0;     /* unknown */
1941                 } else {
1942                         processed_len = state->metablock_size;
1943                         bytenr = btrfs_stack_header_bytenr(
1944                                         (struct btrfs_header *)
1945                                         mapped_datav[0]);
1946                         btrfsic_cmp_log_and_dev_bytenr(state, bytenr, dev_state,
1947                                                        dev_bytenr);
1948                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1949                                 pr_info(
1950                         "written block @%llu (%pg/%llu/?) !found in hash table, M\n",
1951                                        bytenr, dev_state->bdev, dev_bytenr);
1952                 }
1953
1954                 block_ctx.dev = dev_state;
1955                 block_ctx.dev_bytenr = dev_bytenr;
1956                 block_ctx.start = bytenr;
1957                 block_ctx.len = processed_len;
1958                 block_ctx.pagev = NULL;
1959                 block_ctx.mem_to_free = NULL;
1960                 block_ctx.datav = mapped_datav;
1961
1962                 block = btrfsic_block_alloc();
1963                 if (NULL == block) {
1964                         btrfsic_release_block_ctx(&block_ctx);
1965                         goto continue_loop;
1966                 }
1967                 block->dev_state = dev_state;
1968                 block->dev_bytenr = dev_bytenr;
1969                 block->logical_bytenr = bytenr;
1970                 block->is_metadata = is_metadata;
1971                 block->never_written = 0;
1972                 block->iodone_w_error = 0;
1973                 block->mirror_num = 0;  /* unknown */
1974                 block->flush_gen = dev_state->last_flush_gen + 1;
1975                 block->submit_bio_bh_rw = submit_bio_bh_rw;
1976                 if (NULL != bio) {
1977                         block->is_iodone = 0;
1978                         BUG_ON(NULL == bio_is_patched);
1979                         if (!*bio_is_patched) {
1980                                 block->orig_bio_private = bio->bi_private;
1981                                 block->orig_bio_end_io = bio->bi_end_io;
1982                                 block->next_in_same_bio = NULL;
1983                                 bio->bi_private = block;
1984                                 bio->bi_end_io = btrfsic_bio_end_io;
1985                                 *bio_is_patched = 1;
1986                         } else {
1987                                 struct btrfsic_block *chained_block =
1988                                     (struct btrfsic_block *)
1989                                     bio->bi_private;
1990
1991                                 BUG_ON(NULL == chained_block);
1992                                 block->orig_bio_private =
1993                                     chained_block->orig_bio_private;
1994                                 block->orig_bio_end_io =
1995                                     chained_block->orig_bio_end_io;
1996                                 block->next_in_same_bio = chained_block;
1997                                 bio->bi_private = block;
1998                         }
1999                 } else {
2000                         block->is_iodone = 1;
2001                         block->orig_bio_private = NULL;
2002                         block->orig_bio_end_io = NULL;
2003                         block->next_in_same_bio = NULL;
2004                 }
2005                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2006                         pr_info("new written %c-block @%llu (%pg/%llu/%d)\n",
2007                                is_metadata ? 'M' : 'D',
2008                                block->logical_bytenr, block->dev_state->bdev,
2009                                block->dev_bytenr, block->mirror_num);
2010                 list_add(&block->all_blocks_node, &state->all_blocks_list);
2011                 btrfsic_block_hashtable_add(block, &state->block_hashtable);
2012
2013                 if (is_metadata) {
2014                         ret = btrfsic_process_metablock(state, block,
2015                                                         &block_ctx, 0, 0);
2016                         if (ret)
2017                                 pr_info("btrfsic: process_metablock(root @%llu) failed!\n",
2018                                        dev_bytenr);
2019                 }
2020                 btrfsic_release_block_ctx(&block_ctx);
2021         }
2022
2023 continue_loop:
2024         BUG_ON(!processed_len);
2025         dev_bytenr += processed_len;
2026         mapped_datav += processed_len >> PAGE_SHIFT;
2027         num_pages -= processed_len >> PAGE_SHIFT;
2028         goto again;
2029 }
2030
2031 static void btrfsic_bio_end_io(struct bio *bp)
2032 {
2033         struct btrfsic_block *block = bp->bi_private;
2034         int iodone_w_error;
2035
2036         /* mutex is not held! This is not save if IO is not yet completed
2037          * on umount */
2038         iodone_w_error = 0;
2039         if (bp->bi_status)
2040                 iodone_w_error = 1;
2041
2042         BUG_ON(NULL == block);
2043         bp->bi_private = block->orig_bio_private;
2044         bp->bi_end_io = block->orig_bio_end_io;
2045
2046         do {
2047                 struct btrfsic_block *next_block;
2048                 struct btrfsic_dev_state *const dev_state = block->dev_state;
2049
2050                 if ((dev_state->state->print_mask &
2051                      BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2052                         pr_info("bio_end_io(err=%d) for %c @%llu (%pg/%llu/%d)\n",
2053                                bp->bi_status,
2054                                btrfsic_get_block_type(dev_state->state, block),
2055                                block->logical_bytenr, dev_state->bdev,
2056                                block->dev_bytenr, block->mirror_num);
2057                 next_block = block->next_in_same_bio;
2058                 block->iodone_w_error = iodone_w_error;
2059                 if (block->submit_bio_bh_rw & REQ_PREFLUSH) {
2060                         dev_state->last_flush_gen++;
2061                         if ((dev_state->state->print_mask &
2062                              BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2063                                 pr_info("bio_end_io() new %pg flush_gen=%llu\n",
2064                                        dev_state->bdev,
2065                                        dev_state->last_flush_gen);
2066                 }
2067                 if (block->submit_bio_bh_rw & REQ_FUA)
2068                         block->flush_gen = 0; /* FUA completed means block is
2069                                                * on disk */
2070                 block->is_iodone = 1; /* for FLUSH, this releases the block */
2071                 block = next_block;
2072         } while (NULL != block);
2073
2074         bp->bi_end_io(bp);
2075 }
2076
2077 static int btrfsic_process_written_superblock(
2078                 struct btrfsic_state *state,
2079                 struct btrfsic_block *const superblock,
2080                 struct btrfs_super_block *const super_hdr)
2081 {
2082         struct btrfs_fs_info *fs_info = state->fs_info;
2083         int pass;
2084
2085         superblock->generation = btrfs_super_generation(super_hdr);
2086         if (!(superblock->generation > state->max_superblock_generation ||
2087               0 == state->max_superblock_generation)) {
2088                 if (state->print_mask & BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE)
2089                         pr_info(
2090         "btrfsic: superblock @%llu (%pg/%llu/%d) with old gen %llu <= %llu\n",
2091                                superblock->logical_bytenr,
2092                                superblock->dev_state->bdev,
2093                                superblock->dev_bytenr, superblock->mirror_num,
2094                                btrfs_super_generation(super_hdr),
2095                                state->max_superblock_generation);
2096         } else {
2097                 if (state->print_mask & BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE)
2098                         pr_info(
2099         "btrfsic: got new superblock @%llu (%pg/%llu/%d) with new gen %llu > %llu\n",
2100                                superblock->logical_bytenr,
2101                                superblock->dev_state->bdev,
2102                                superblock->dev_bytenr, superblock->mirror_num,
2103                                btrfs_super_generation(super_hdr),
2104                                state->max_superblock_generation);
2105
2106                 state->max_superblock_generation =
2107                     btrfs_super_generation(super_hdr);
2108                 state->latest_superblock = superblock;
2109         }
2110
2111         for (pass = 0; pass < 3; pass++) {
2112                 int ret;
2113                 u64 next_bytenr;
2114                 struct btrfsic_block *next_block;
2115                 struct btrfsic_block_data_ctx tmp_next_block_ctx;
2116                 struct btrfsic_block_link *l;
2117                 int num_copies;
2118                 int mirror_num;
2119                 const char *additional_string = NULL;
2120                 struct btrfs_disk_key tmp_disk_key = {0};
2121
2122                 btrfs_set_disk_key_objectid(&tmp_disk_key,
2123                                             BTRFS_ROOT_ITEM_KEY);
2124                 btrfs_set_disk_key_objectid(&tmp_disk_key, 0);
2125
2126                 switch (pass) {
2127                 case 0:
2128                         btrfs_set_disk_key_objectid(&tmp_disk_key,
2129                                                     BTRFS_ROOT_TREE_OBJECTID);
2130                         additional_string = "root ";
2131                         next_bytenr = btrfs_super_root(super_hdr);
2132                         if (state->print_mask &
2133                             BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
2134                                 pr_info("root@%llu\n", next_bytenr);
2135                         break;
2136                 case 1:
2137                         btrfs_set_disk_key_objectid(&tmp_disk_key,
2138                                                     BTRFS_CHUNK_TREE_OBJECTID);
2139                         additional_string = "chunk ";
2140                         next_bytenr = btrfs_super_chunk_root(super_hdr);
2141                         if (state->print_mask &
2142                             BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
2143                                 pr_info("chunk@%llu\n", next_bytenr);
2144                         break;
2145                 case 2:
2146                         btrfs_set_disk_key_objectid(&tmp_disk_key,
2147                                                     BTRFS_TREE_LOG_OBJECTID);
2148                         additional_string = "log ";
2149                         next_bytenr = btrfs_super_log_root(super_hdr);
2150                         if (0 == next_bytenr)
2151                                 continue;
2152                         if (state->print_mask &
2153                             BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
2154                                 pr_info("log@%llu\n", next_bytenr);
2155                         break;
2156                 }
2157
2158                 num_copies = btrfs_num_copies(fs_info, next_bytenr,
2159                                               BTRFS_SUPER_INFO_SIZE);
2160                 if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
2161                         pr_info("num_copies(log_bytenr=%llu) = %d\n",
2162                                next_bytenr, num_copies);
2163                 for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
2164                         int was_created;
2165
2166                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2167                                 pr_info("btrfsic_process_written_superblock(mirror_num=%d)\n", mirror_num);
2168                         ret = btrfsic_map_block(state, next_bytenr,
2169                                                 BTRFS_SUPER_INFO_SIZE,
2170                                                 &tmp_next_block_ctx,
2171                                                 mirror_num);
2172                         if (ret) {
2173                                 pr_info("btrfsic: btrfsic_map_block(@%llu, mirror=%d) failed!\n",
2174                                        next_bytenr, mirror_num);
2175                                 return -1;
2176                         }
2177
2178                         next_block = btrfsic_block_lookup_or_add(
2179                                         state,
2180                                         &tmp_next_block_ctx,
2181                                         additional_string,
2182                                         1, 0, 1,
2183                                         mirror_num,
2184                                         &was_created);
2185                         if (NULL == next_block) {
2186                                 btrfsic_release_block_ctx(&tmp_next_block_ctx);
2187                                 return -1;
2188                         }
2189
2190                         next_block->disk_key = tmp_disk_key;
2191                         if (was_created)
2192                                 next_block->generation =
2193                                     BTRFSIC_GENERATION_UNKNOWN;
2194                         l = btrfsic_block_link_lookup_or_add(
2195                                         state,
2196                                         &tmp_next_block_ctx,
2197                                         next_block,
2198                                         superblock,
2199                                         BTRFSIC_GENERATION_UNKNOWN);
2200                         btrfsic_release_block_ctx(&tmp_next_block_ctx);
2201                         if (NULL == l)
2202                                 return -1;
2203                 }
2204         }
2205
2206         if (WARN_ON(-1 == btrfsic_check_all_ref_blocks(state, superblock, 0)))
2207                 btrfsic_dump_tree(state);
2208
2209         return 0;
2210 }
2211
2212 static int btrfsic_check_all_ref_blocks(struct btrfsic_state *state,
2213                                         struct btrfsic_block *const block,
2214                                         int recursion_level)
2215 {
2216         const struct btrfsic_block_link *l;
2217         int ret = 0;
2218
2219         if (recursion_level >= 3 + BTRFS_MAX_LEVEL) {
2220                 /*
2221                  * Note that this situation can happen and does not
2222                  * indicate an error in regular cases. It happens
2223                  * when disk blocks are freed and later reused.
2224                  * The check-integrity module is not aware of any
2225                  * block free operations, it just recognizes block
2226                  * write operations. Therefore it keeps the linkage
2227                  * information for a block until a block is
2228                  * rewritten. This can temporarily cause incorrect
2229                  * and even circular linkage information. This
2230                  * causes no harm unless such blocks are referenced
2231                  * by the most recent super block.
2232                  */
2233                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2234                         pr_info("btrfsic: abort cyclic linkage (case 1).\n");
2235
2236                 return ret;
2237         }
2238
2239         /*
2240          * This algorithm is recursive because the amount of used stack
2241          * space is very small and the max recursion depth is limited.
2242          */
2243         list_for_each_entry(l, &block->ref_to_list, node_ref_to) {
2244                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2245                         pr_info(
2246                 "rl=%d, %c @%llu (%pg/%llu/%d) %u* refers to %c @%llu (%pg/%llu/%d)\n",
2247                                recursion_level,
2248                                btrfsic_get_block_type(state, block),
2249                                block->logical_bytenr, block->dev_state->bdev,
2250                                block->dev_bytenr, block->mirror_num,
2251                                l->ref_cnt,
2252                                btrfsic_get_block_type(state, l->block_ref_to),
2253                                l->block_ref_to->logical_bytenr,
2254                                l->block_ref_to->dev_state->bdev,
2255                                l->block_ref_to->dev_bytenr,
2256                                l->block_ref_to->mirror_num);
2257                 if (l->block_ref_to->never_written) {
2258                         pr_info(
2259 "btrfs: attempt to write superblock which references block %c @%llu (%pg/%llu/%d) which is never written!\n",
2260                                btrfsic_get_block_type(state, l->block_ref_to),
2261                                l->block_ref_to->logical_bytenr,
2262                                l->block_ref_to->dev_state->bdev,
2263                                l->block_ref_to->dev_bytenr,
2264                                l->block_ref_to->mirror_num);
2265                         ret = -1;
2266                 } else if (!l->block_ref_to->is_iodone) {
2267                         pr_info(
2268 "btrfs: attempt to write superblock which references block %c @%llu (%pg/%llu/%d) which is not yet iodone!\n",
2269                                btrfsic_get_block_type(state, l->block_ref_to),
2270                                l->block_ref_to->logical_bytenr,
2271                                l->block_ref_to->dev_state->bdev,
2272                                l->block_ref_to->dev_bytenr,
2273                                l->block_ref_to->mirror_num);
2274                         ret = -1;
2275                 } else if (l->block_ref_to->iodone_w_error) {
2276                         pr_info(
2277 "btrfs: attempt to write superblock which references block %c @%llu (%pg/%llu/%d) which has write error!\n",
2278                                btrfsic_get_block_type(state, l->block_ref_to),
2279                                l->block_ref_to->logical_bytenr,
2280                                l->block_ref_to->dev_state->bdev,
2281                                l->block_ref_to->dev_bytenr,
2282                                l->block_ref_to->mirror_num);
2283                         ret = -1;
2284                 } else if (l->parent_generation !=
2285                            l->block_ref_to->generation &&
2286                            BTRFSIC_GENERATION_UNKNOWN !=
2287                            l->parent_generation &&
2288                            BTRFSIC_GENERATION_UNKNOWN !=
2289                            l->block_ref_to->generation) {
2290                         pr_info(
2291 "btrfs: attempt to write superblock which references block %c @%llu (%pg/%llu/%d) with generation %llu != parent generation %llu!\n",
2292                                btrfsic_get_block_type(state, l->block_ref_to),
2293                                l->block_ref_to->logical_bytenr,
2294                                l->block_ref_to->dev_state->bdev,
2295                                l->block_ref_to->dev_bytenr,
2296                                l->block_ref_to->mirror_num,
2297                                l->block_ref_to->generation,
2298                                l->parent_generation);
2299                         ret = -1;
2300                 } else if (l->block_ref_to->flush_gen >
2301                            l->block_ref_to->dev_state->last_flush_gen) {
2302                         pr_info(
2303 "btrfs: attempt to write superblock which references block %c @%llu (%pg/%llu/%d) which is not flushed out of disk's write cache (block flush_gen=%llu, dev->flush_gen=%llu)!\n",
2304                                btrfsic_get_block_type(state, l->block_ref_to),
2305                                l->block_ref_to->logical_bytenr,
2306                                l->block_ref_to->dev_state->bdev,
2307                                l->block_ref_to->dev_bytenr,
2308                                l->block_ref_to->mirror_num, block->flush_gen,
2309                                l->block_ref_to->dev_state->last_flush_gen);
2310                         ret = -1;
2311                 } else if (-1 == btrfsic_check_all_ref_blocks(state,
2312                                                               l->block_ref_to,
2313                                                               recursion_level +
2314                                                               1)) {
2315                         ret = -1;
2316                 }
2317         }
2318
2319         return ret;
2320 }
2321
2322 static int btrfsic_is_block_ref_by_superblock(
2323                 const struct btrfsic_state *state,
2324                 const struct btrfsic_block *block,
2325                 int recursion_level)
2326 {
2327         const struct btrfsic_block_link *l;
2328
2329         if (recursion_level >= 3 + BTRFS_MAX_LEVEL) {
2330                 /* refer to comment at "abort cyclic linkage (case 1)" */
2331                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2332                         pr_info("btrfsic: abort cyclic linkage (case 2).\n");
2333
2334                 return 0;
2335         }
2336
2337         /*
2338          * This algorithm is recursive because the amount of used stack space
2339          * is very small and the max recursion depth is limited.
2340          */
2341         list_for_each_entry(l, &block->ref_from_list, node_ref_from) {
2342                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2343                         pr_info(
2344         "rl=%d, %c @%llu (%pg/%llu/%d) is ref %u* from %c @%llu (%pg/%llu/%d)\n",
2345                                recursion_level,
2346                                btrfsic_get_block_type(state, block),
2347                                block->logical_bytenr, block->dev_state->bdev,
2348                                block->dev_bytenr, block->mirror_num,
2349                                l->ref_cnt,
2350                                btrfsic_get_block_type(state, l->block_ref_from),
2351                                l->block_ref_from->logical_bytenr,
2352                                l->block_ref_from->dev_state->bdev,
2353                                l->block_ref_from->dev_bytenr,
2354                                l->block_ref_from->mirror_num);
2355                 if (l->block_ref_from->is_superblock &&
2356                     state->latest_superblock->dev_bytenr ==
2357                     l->block_ref_from->dev_bytenr &&
2358                     state->latest_superblock->dev_state->bdev ==
2359                     l->block_ref_from->dev_state->bdev)
2360                         return 1;
2361                 else if (btrfsic_is_block_ref_by_superblock(state,
2362                                                             l->block_ref_from,
2363                                                             recursion_level +
2364                                                             1))
2365                         return 1;
2366         }
2367
2368         return 0;
2369 }
2370
2371 static void btrfsic_print_add_link(const struct btrfsic_state *state,
2372                                    const struct btrfsic_block_link *l)
2373 {
2374         pr_info("add %u* link from %c @%llu (%pg/%llu/%d) to %c @%llu (%pg/%llu/%d)\n",
2375                l->ref_cnt,
2376                btrfsic_get_block_type(state, l->block_ref_from),
2377                l->block_ref_from->logical_bytenr,
2378                l->block_ref_from->dev_state->bdev,
2379                l->block_ref_from->dev_bytenr, l->block_ref_from->mirror_num,
2380                btrfsic_get_block_type(state, l->block_ref_to),
2381                l->block_ref_to->logical_bytenr,
2382                l->block_ref_to->dev_state->bdev, l->block_ref_to->dev_bytenr,
2383                l->block_ref_to->mirror_num);
2384 }
2385
2386 static void btrfsic_print_rem_link(const struct btrfsic_state *state,
2387                                    const struct btrfsic_block_link *l)
2388 {
2389         pr_info("rem %u* link from %c @%llu (%pg/%llu/%d) to %c @%llu (%pg/%llu/%d)\n",
2390                l->ref_cnt,
2391                btrfsic_get_block_type(state, l->block_ref_from),
2392                l->block_ref_from->logical_bytenr,
2393                l->block_ref_from->dev_state->bdev,
2394                l->block_ref_from->dev_bytenr, l->block_ref_from->mirror_num,
2395                btrfsic_get_block_type(state, l->block_ref_to),
2396                l->block_ref_to->logical_bytenr,
2397                l->block_ref_to->dev_state->bdev, l->block_ref_to->dev_bytenr,
2398                l->block_ref_to->mirror_num);
2399 }
2400
2401 static char btrfsic_get_block_type(const struct btrfsic_state *state,
2402                                    const struct btrfsic_block *block)
2403 {
2404         if (block->is_superblock &&
2405             state->latest_superblock->dev_bytenr == block->dev_bytenr &&
2406             state->latest_superblock->dev_state->bdev == block->dev_state->bdev)
2407                 return 'S';
2408         else if (block->is_superblock)
2409                 return 's';
2410         else if (block->is_metadata)
2411                 return 'M';
2412         else
2413                 return 'D';
2414 }
2415
2416 static void btrfsic_dump_tree(const struct btrfsic_state *state)
2417 {
2418         btrfsic_dump_tree_sub(state, state->latest_superblock, 0);
2419 }
2420
2421 static void btrfsic_dump_tree_sub(const struct btrfsic_state *state,
2422                                   const struct btrfsic_block *block,
2423                                   int indent_level)
2424 {
2425         const struct btrfsic_block_link *l;
2426         int indent_add;
2427         static char buf[80];
2428         int cursor_position;
2429
2430         /*
2431          * Should better fill an on-stack buffer with a complete line and
2432          * dump it at once when it is time to print a newline character.
2433          */
2434
2435         /*
2436          * This algorithm is recursive because the amount of used stack space
2437          * is very small and the max recursion depth is limited.
2438          */
2439         indent_add = sprintf(buf, "%c-%llu(%pg/%llu/%u)",
2440                              btrfsic_get_block_type(state, block),
2441                              block->logical_bytenr, block->dev_state->bdev,
2442                              block->dev_bytenr, block->mirror_num);
2443         if (indent_level + indent_add > BTRFSIC_TREE_DUMP_MAX_INDENT_LEVEL) {
2444                 printk("[...]\n");
2445                 return;
2446         }
2447         printk(buf);
2448         indent_level += indent_add;
2449         if (list_empty(&block->ref_to_list)) {
2450                 printk("\n");
2451                 return;
2452         }
2453         if (block->mirror_num > 1 &&
2454             !(state->print_mask & BTRFSIC_PRINT_MASK_TREE_WITH_ALL_MIRRORS)) {
2455                 printk(" [...]\n");
2456                 return;
2457         }
2458
2459         cursor_position = indent_level;
2460         list_for_each_entry(l, &block->ref_to_list, node_ref_to) {
2461                 while (cursor_position < indent_level) {
2462                         printk(" ");
2463                         cursor_position++;
2464                 }
2465                 if (l->ref_cnt > 1)
2466                         indent_add = sprintf(buf, " %d*--> ", l->ref_cnt);
2467                 else
2468                         indent_add = sprintf(buf, " --> ");
2469                 if (indent_level + indent_add >
2470                     BTRFSIC_TREE_DUMP_MAX_INDENT_LEVEL) {
2471                         printk("[...]\n");
2472                         cursor_position = 0;
2473                         continue;
2474                 }
2475
2476                 printk(buf);
2477
2478                 btrfsic_dump_tree_sub(state, l->block_ref_to,
2479                                       indent_level + indent_add);
2480                 cursor_position = 0;
2481         }
2482 }
2483
2484 static struct btrfsic_block_link *btrfsic_block_link_lookup_or_add(
2485                 struct btrfsic_state *state,
2486                 struct btrfsic_block_data_ctx *next_block_ctx,
2487                 struct btrfsic_block *next_block,
2488                 struct btrfsic_block *from_block,
2489                 u64 parent_generation)
2490 {
2491         struct btrfsic_block_link *l;
2492
2493         l = btrfsic_block_link_hashtable_lookup(next_block_ctx->dev->bdev,
2494                                                 next_block_ctx->dev_bytenr,
2495                                                 from_block->dev_state->bdev,
2496                                                 from_block->dev_bytenr,
2497                                                 &state->block_link_hashtable);
2498         if (NULL == l) {
2499                 l = btrfsic_block_link_alloc();
2500                 if (!l)
2501                         return NULL;
2502
2503                 l->block_ref_to = next_block;
2504                 l->block_ref_from = from_block;
2505                 l->ref_cnt = 1;
2506                 l->parent_generation = parent_generation;
2507
2508                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2509                         btrfsic_print_add_link(state, l);
2510
2511                 list_add(&l->node_ref_to, &from_block->ref_to_list);
2512                 list_add(&l->node_ref_from, &next_block->ref_from_list);
2513
2514                 btrfsic_block_link_hashtable_add(l,
2515                                                  &state->block_link_hashtable);
2516         } else {
2517                 l->ref_cnt++;
2518                 l->parent_generation = parent_generation;
2519                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2520                         btrfsic_print_add_link(state, l);
2521         }
2522
2523         return l;
2524 }
2525
2526 static struct btrfsic_block *btrfsic_block_lookup_or_add(
2527                 struct btrfsic_state *state,
2528                 struct btrfsic_block_data_ctx *block_ctx,
2529                 const char *additional_string,
2530                 int is_metadata,
2531                 int is_iodone,
2532                 int never_written,
2533                 int mirror_num,
2534                 int *was_created)
2535 {
2536         struct btrfsic_block *block;
2537
2538         block = btrfsic_block_hashtable_lookup(block_ctx->dev->bdev,
2539                                                block_ctx->dev_bytenr,
2540                                                &state->block_hashtable);
2541         if (NULL == block) {
2542                 struct btrfsic_dev_state *dev_state;
2543
2544                 block = btrfsic_block_alloc();
2545                 if (!block)
2546                         return NULL;
2547
2548                 dev_state = btrfsic_dev_state_lookup(block_ctx->dev->bdev->bd_dev);
2549                 if (NULL == dev_state) {
2550                         pr_info("btrfsic: error, lookup dev_state failed!\n");
2551                         btrfsic_block_free(block);
2552                         return NULL;
2553                 }
2554                 block->dev_state = dev_state;
2555                 block->dev_bytenr = block_ctx->dev_bytenr;
2556                 block->logical_bytenr = block_ctx->start;
2557                 block->is_metadata = is_metadata;
2558                 block->is_iodone = is_iodone;
2559                 block->never_written = never_written;
2560                 block->mirror_num = mirror_num;
2561                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2562                         pr_info("New %s%c-block @%llu (%pg/%llu/%d)\n",
2563                                additional_string,
2564                                btrfsic_get_block_type(state, block),
2565                                block->logical_bytenr, dev_state->bdev,
2566                                block->dev_bytenr, mirror_num);
2567                 list_add(&block->all_blocks_node, &state->all_blocks_list);
2568                 btrfsic_block_hashtable_add(block, &state->block_hashtable);
2569                 if (NULL != was_created)
2570                         *was_created = 1;
2571         } else {
2572                 if (NULL != was_created)
2573                         *was_created = 0;
2574         }
2575
2576         return block;
2577 }
2578
2579 static void btrfsic_cmp_log_and_dev_bytenr(struct btrfsic_state *state,
2580                                            u64 bytenr,
2581                                            struct btrfsic_dev_state *dev_state,
2582                                            u64 dev_bytenr)
2583 {
2584         struct btrfs_fs_info *fs_info = state->fs_info;
2585         struct btrfsic_block_data_ctx block_ctx;
2586         int num_copies;
2587         int mirror_num;
2588         int match = 0;
2589         int ret;
2590
2591         num_copies = btrfs_num_copies(fs_info, bytenr, state->metablock_size);
2592
2593         for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
2594                 ret = btrfsic_map_block(state, bytenr, state->metablock_size,
2595                                         &block_ctx, mirror_num);
2596                 if (ret) {
2597                         pr_info("btrfsic: btrfsic_map_block(logical @%llu, mirror %d) failed!\n",
2598                                bytenr, mirror_num);
2599                         continue;
2600                 }
2601
2602                 if (dev_state->bdev == block_ctx.dev->bdev &&
2603                     dev_bytenr == block_ctx.dev_bytenr) {
2604                         match++;
2605                         btrfsic_release_block_ctx(&block_ctx);
2606                         break;
2607                 }
2608                 btrfsic_release_block_ctx(&block_ctx);
2609         }
2610
2611         if (WARN_ON(!match)) {
2612                 pr_info(
2613 "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=%pg, phys_bytenr=%llu)!\n",
2614                        bytenr, dev_state->bdev, dev_bytenr);
2615                 for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
2616                         ret = btrfsic_map_block(state, bytenr,
2617                                                 state->metablock_size,
2618                                                 &block_ctx, mirror_num);
2619                         if (ret)
2620                                 continue;
2621
2622                         pr_info("read logical bytenr @%llu maps to (%pg/%llu/%d)\n",
2623                                bytenr, block_ctx.dev->bdev,
2624                                block_ctx.dev_bytenr, mirror_num);
2625                 }
2626         }
2627 }
2628
2629 static struct btrfsic_dev_state *btrfsic_dev_state_lookup(dev_t dev)
2630 {
2631         return btrfsic_dev_state_hashtable_lookup(dev,
2632                                                   &btrfsic_dev_state_hashtable);
2633 }
2634
2635 static void btrfsic_check_write_bio(struct bio *bio, struct btrfsic_dev_state *dev_state)
2636 {
2637         unsigned int segs = bio_segments(bio);
2638         u64 dev_bytenr = 512 * bio->bi_iter.bi_sector;
2639         u64 cur_bytenr = dev_bytenr;
2640         struct bvec_iter iter;
2641         struct bio_vec bvec;
2642         char **mapped_datav;
2643         int bio_is_patched = 0;
2644         int i = 0;
2645
2646         if (dev_state->state->print_mask & BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
2647                 pr_info(
2648 "submit_bio(rw=%d,0x%x, bi_vcnt=%u, bi_sector=%llu (bytenr %llu), bi_bdev=%p)\n",
2649                        bio_op(bio), bio->bi_opf, segs,
2650                        bio->bi_iter.bi_sector, dev_bytenr, bio->bi_bdev);
2651
2652         mapped_datav = kmalloc_array(segs, sizeof(*mapped_datav), GFP_NOFS);
2653         if (!mapped_datav)
2654                 return;
2655
2656         bio_for_each_segment(bvec, bio, iter) {
2657                 BUG_ON(bvec.bv_len != PAGE_SIZE);
2658                 mapped_datav[i] = page_address(bvec.bv_page);
2659                 i++;
2660
2661                 if (dev_state->state->print_mask &
2662                     BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH_VERBOSE)
2663                         pr_info("#%u: bytenr=%llu, len=%u, offset=%u\n",
2664                                i, cur_bytenr, bvec.bv_len, bvec.bv_offset);
2665                 cur_bytenr += bvec.bv_len;
2666         }
2667
2668         btrfsic_process_written_block(dev_state, dev_bytenr, mapped_datav, segs,
2669                                       bio, &bio_is_patched, bio->bi_opf);
2670         kfree(mapped_datav);
2671 }
2672
2673 static void btrfsic_check_flush_bio(struct bio *bio, struct btrfsic_dev_state *dev_state)
2674 {
2675         if (dev_state->state->print_mask & BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
2676                 pr_info("submit_bio(rw=%d,0x%x FLUSH, bdev=%p)\n",
2677                        bio_op(bio), bio->bi_opf, bio->bi_bdev);
2678
2679         if (dev_state->dummy_block_for_bio_bh_flush.is_iodone) {
2680                 struct btrfsic_block *const block =
2681                         &dev_state->dummy_block_for_bio_bh_flush;
2682
2683                 block->is_iodone = 0;
2684                 block->never_written = 0;
2685                 block->iodone_w_error = 0;
2686                 block->flush_gen = dev_state->last_flush_gen + 1;
2687                 block->submit_bio_bh_rw = bio->bi_opf;
2688                 block->orig_bio_private = bio->bi_private;
2689                 block->orig_bio_end_io = bio->bi_end_io;
2690                 block->next_in_same_bio = NULL;
2691                 bio->bi_private = block;
2692                 bio->bi_end_io = btrfsic_bio_end_io;
2693         } else if ((dev_state->state->print_mask &
2694                    (BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH |
2695                     BTRFSIC_PRINT_MASK_VERBOSE))) {
2696                 pr_info(
2697 "btrfsic_submit_bio(%pg) with FLUSH but dummy block already in use (ignored)!\n",
2698                        dev_state->bdev);
2699         }
2700 }
2701
2702 void btrfsic_check_bio(struct bio *bio)
2703 {
2704         struct btrfsic_dev_state *dev_state;
2705
2706         if (!btrfsic_is_initialized)
2707                 return;
2708
2709         /*
2710          * We can be called before btrfsic_mount, so there might not be a
2711          * dev_state.
2712          */
2713         dev_state = btrfsic_dev_state_lookup(bio->bi_bdev->bd_dev);
2714         mutex_lock(&btrfsic_mutex);
2715         if (dev_state) {
2716                 if (bio_op(bio) == REQ_OP_WRITE && bio_has_data(bio))
2717                         btrfsic_check_write_bio(bio, dev_state);
2718                 else if (bio->bi_opf & REQ_PREFLUSH)
2719                         btrfsic_check_flush_bio(bio, dev_state);
2720         }
2721         mutex_unlock(&btrfsic_mutex);
2722 }
2723
2724 int btrfsic_mount(struct btrfs_fs_info *fs_info,
2725                   struct btrfs_fs_devices *fs_devices,
2726                   int including_extent_data, u32 print_mask)
2727 {
2728         int ret;
2729         struct btrfsic_state *state;
2730         struct list_head *dev_head = &fs_devices->devices;
2731         struct btrfs_device *device;
2732
2733         if (!PAGE_ALIGNED(fs_info->nodesize)) {
2734                 pr_info("btrfsic: cannot handle nodesize %d not being a multiple of PAGE_SIZE %ld!\n",
2735                        fs_info->nodesize, PAGE_SIZE);
2736                 return -1;
2737         }
2738         if (!PAGE_ALIGNED(fs_info->sectorsize)) {
2739                 pr_info("btrfsic: cannot handle sectorsize %d not being a multiple of PAGE_SIZE %ld!\n",
2740                        fs_info->sectorsize, PAGE_SIZE);
2741                 return -1;
2742         }
2743         state = kvzalloc(sizeof(*state), GFP_KERNEL);
2744         if (!state)
2745                 return -ENOMEM;
2746
2747         if (!btrfsic_is_initialized) {
2748                 mutex_init(&btrfsic_mutex);
2749                 btrfsic_dev_state_hashtable_init(&btrfsic_dev_state_hashtable);
2750                 btrfsic_is_initialized = 1;
2751         }
2752         mutex_lock(&btrfsic_mutex);
2753         state->fs_info = fs_info;
2754         state->print_mask = print_mask;
2755         state->include_extent_data = including_extent_data;
2756         state->metablock_size = fs_info->nodesize;
2757         state->datablock_size = fs_info->sectorsize;
2758         INIT_LIST_HEAD(&state->all_blocks_list);
2759         btrfsic_block_hashtable_init(&state->block_hashtable);
2760         btrfsic_block_link_hashtable_init(&state->block_link_hashtable);
2761         state->max_superblock_generation = 0;
2762         state->latest_superblock = NULL;
2763
2764         list_for_each_entry(device, dev_head, dev_list) {
2765                 struct btrfsic_dev_state *ds;
2766
2767                 if (!device->bdev || !device->name)
2768                         continue;
2769
2770                 ds = btrfsic_dev_state_alloc();
2771                 if (NULL == ds) {
2772                         mutex_unlock(&btrfsic_mutex);
2773                         return -ENOMEM;
2774                 }
2775                 ds->bdev = device->bdev;
2776                 ds->state = state;
2777                 btrfsic_dev_state_hashtable_add(ds,
2778                                                 &btrfsic_dev_state_hashtable);
2779         }
2780
2781         ret = btrfsic_process_superblock(state, fs_devices);
2782         if (0 != ret) {
2783                 mutex_unlock(&btrfsic_mutex);
2784                 btrfsic_unmount(fs_devices);
2785                 return ret;
2786         }
2787
2788         if (state->print_mask & BTRFSIC_PRINT_MASK_INITIAL_DATABASE)
2789                 btrfsic_dump_database(state);
2790         if (state->print_mask & BTRFSIC_PRINT_MASK_INITIAL_TREE)
2791                 btrfsic_dump_tree(state);
2792
2793         mutex_unlock(&btrfsic_mutex);
2794         return 0;
2795 }
2796
2797 void btrfsic_unmount(struct btrfs_fs_devices *fs_devices)
2798 {
2799         struct btrfsic_block *b_all, *tmp_all;
2800         struct btrfsic_state *state;
2801         struct list_head *dev_head = &fs_devices->devices;
2802         struct btrfs_device *device;
2803
2804         if (!btrfsic_is_initialized)
2805                 return;
2806
2807         mutex_lock(&btrfsic_mutex);
2808
2809         state = NULL;
2810         list_for_each_entry(device, dev_head, dev_list) {
2811                 struct btrfsic_dev_state *ds;
2812
2813                 if (!device->bdev || !device->name)
2814                         continue;
2815
2816                 ds = btrfsic_dev_state_hashtable_lookup(
2817                                 device->bdev->bd_dev,
2818                                 &btrfsic_dev_state_hashtable);
2819                 if (NULL != ds) {
2820                         state = ds->state;
2821                         btrfsic_dev_state_hashtable_remove(ds);
2822                         btrfsic_dev_state_free(ds);
2823                 }
2824         }
2825
2826         if (NULL == state) {
2827                 pr_info("btrfsic: error, cannot find state information on umount!\n");
2828                 mutex_unlock(&btrfsic_mutex);
2829                 return;
2830         }
2831
2832         /*
2833          * Don't care about keeping the lists' state up to date,
2834          * just free all memory that was allocated dynamically.
2835          * Free the blocks and the block_links.
2836          */
2837         list_for_each_entry_safe(b_all, tmp_all, &state->all_blocks_list,
2838                                  all_blocks_node) {
2839                 struct btrfsic_block_link *l, *tmp;
2840
2841                 list_for_each_entry_safe(l, tmp, &b_all->ref_to_list,
2842                                          node_ref_to) {
2843                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2844                                 btrfsic_print_rem_link(state, l);
2845
2846                         l->ref_cnt--;
2847                         if (0 == l->ref_cnt)
2848                                 btrfsic_block_link_free(l);
2849                 }
2850
2851                 if (b_all->is_iodone || b_all->never_written)
2852                         btrfsic_block_free(b_all);
2853                 else
2854                         pr_info(
2855 "btrfs: attempt to free %c-block @%llu (%pg/%llu/%d) on umount which is not yet iodone!\n",
2856                                btrfsic_get_block_type(state, b_all),
2857                                b_all->logical_bytenr, b_all->dev_state->bdev,
2858                                b_all->dev_bytenr, b_all->mirror_num);
2859         }
2860
2861         mutex_unlock(&btrfsic_mutex);
2862
2863         kvfree(state);
2864 }