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