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