fs/btrfs/check-integrity.c

   1 /*
   2  * Copyright (C) STRATO AG 2011.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18
  19 /*
  20  * This module can be used to catch cases when the btrfs kernel
  21  * code executes write requests to the disk that bring the file
  22  * system in an inconsistent state. In such a state, a power-loss
  23  * or kernel panic event would cause that the data on disk is
  24  * lost or at least damaged.
  25  *
  26  * Code is added that examines all block write requests during
  27  * runtime (including writes of the super block). Three rules
  28  * are verified and an error is printed on violation of the
  29  * rules:
  30  * 1. It is not allowed to write a disk block which is
  31  *    currently referenced by the super block (either directly
  32  *    or indirectly).
  33  * 2. When a super block is written, it is verified that all
  34  *    referenced (directly or indirectly) blocks fulfill the
  35  *    following requirements:
  36  *    2a. All referenced blocks have either been present when
  37  *        the file system was mounted, (i.e., they have been
  38  *        referenced by the super block) or they have been
  39  *        written since then and the write completion callback
  40  *        was called and no write error was indicated and a
  41  *        FLUSH request to the device where these blocks are
  42  *        located was received and completed.
  43  *    2b. All referenced blocks need to have a generation
  44  *        number which is equal to the parent's number.
  45  *
  46  * One issue that was found using this module was that the log
  47  * tree on disk became temporarily corrupted because disk blocks
  48  * that had been in use for the log tree had been freed and
  49  * reused too early, while being referenced by the written super
  50  * block.
  51  *
  52  * The search term in the kernel log that can be used to filter
  53  * on the existence of detected integrity issues is
  54  * "btrfs: attempt".
  55  *
  56  * The integrity check is enabled via mount options. These
  57  * mount options are only supported if the integrity check
  58  * tool is compiled by defining BTRFS_FS_CHECK_INTEGRITY.
  59  *
  60  * Example #1, apply integrity checks to all metadata:
  61  * mount /dev/sdb1 /mnt -o check_int
  62  *
  63  * Example #2, apply integrity checks to all metadata and
  64  * to data extents:
  65  * mount /dev/sdb1 /mnt -o check_int_data
  66  *
  67  * Example #3, apply integrity checks to all metadata and dump
  68  * the tree that the super block references to kernel messages
  69  * each time after a super block was written:
  70  * mount /dev/sdb1 /mnt -o check_int,check_int_print_mask=263
  71  *
  72  * If the integrity check tool is included and activated in
  73  * the mount options, plenty of kernel memory is used, and
  74  * plenty of additional CPU cycles are spent. Enabling this
  75  * functionality is not intended for normal use. In most
  76  * cases, unless you are a btrfs developer who needs to verify
  77  * the integrity of (super)-block write requests, do not
  78  * enable the config option BTRFS_FS_CHECK_INTEGRITY to
  79  * include and compile the integrity check tool.
  80  *
  81  * Expect millions of lines of information in the kernel log with an
  82  * enabled check_int_print_mask. Therefore set LOG_BUF_SHIFT in the
  83  * kernel config to at least 26 (which is 64MB). Usually the value is
  84  * limited to 21 (which is 2MB) in init/Kconfig. The file needs to be
  85  * changed like this before LOG_BUF_SHIFT can be set to a high value:
  86  * config LOG_BUF_SHIFT
  87  *       int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
  88  *       range 12 30
  89  */
  90
  91 #include <linux/sched.h>
  92 #include <linux/slab.h>
  93 #include <linux/buffer_head.h>
  94 #include <linux/mutex.h>
  95 #include <linux/genhd.h>
  96 #include <linux/blkdev.h>
  97 #include <linux/vmalloc.h>
  98 #include <linux/string.h>
  99 #include "ctree.h"
 100 #include "disk-io.h"
 101 #include "hash.h"
 102 #include "transaction.h"
 103 #include "extent_io.h"
 104 #include "volumes.h"
 105 #include "print-tree.h"
 106 #include "locking.h"
 107 #include "check-integrity.h"
 108 #include "rcu-string.h"
 109 #include "compression.h"
 110
 111 #define BTRFSIC_BLOCK_HASHTABLE_SIZE 0x10000
 112 #define BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE 0x10000
 113 #define BTRFSIC_DEV2STATE_HASHTABLE_SIZE 0x100
 114 #define BTRFSIC_BLOCK_MAGIC_NUMBER 0x14491051
 115 #define BTRFSIC_BLOCK_LINK_MAGIC_NUMBER 0x11070807
 116 #define BTRFSIC_DEV2STATE_MAGIC_NUMBER 0x20111530
 117 #define BTRFSIC_BLOCK_STACK_FRAME_MAGIC_NUMBER 20111300
 118 #define BTRFSIC_TREE_DUMP_MAX_INDENT_LEVEL (200 - 6)    /* in characters,
 119                                                          * excluding " [...]" */
 120 #define BTRFSIC_GENERATION_UNKNOWN ((u64)-1)
 121
 122 /*
 123  * The definition of the bitmask fields for the print_mask.
 124  * They are specified with the mount option check_integrity_print_mask.
 125  */
 126 #define BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE                     0x00000001
 127 #define BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION         0x00000002
 128 #define BTRFSIC_PRINT_MASK_TREE_AFTER_SB_WRITE                  0x00000004
 129 #define BTRFSIC_PRINT_MASK_TREE_BEFORE_SB_WRITE                 0x00000008
 130 #define BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH                        0x00000010
 131 #define BTRFSIC_PRINT_MASK_END_IO_BIO_BH                        0x00000020
 132 #define BTRFSIC_PRINT_MASK_VERBOSE                              0x00000040
 133 #define BTRFSIC_PRINT_MASK_VERY_VERBOSE                         0x00000080
 134 #define BTRFSIC_PRINT_MASK_INITIAL_TREE                         0x00000100
 135 #define BTRFSIC_PRINT_MASK_INITIAL_ALL_TREES                    0x00000200
 136 #define BTRFSIC_PRINT_MASK_INITIAL_DATABASE                     0x00000400
 137 #define BTRFSIC_PRINT_MASK_NUM_COPIES                           0x00000800
 138 #define BTRFSIC_PRINT_MASK_TREE_WITH_ALL_MIRRORS                0x00001000
 139 #define BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH_VERBOSE                0x00002000
 140
 141 struct btrfsic_dev_state;
 142 struct btrfsic_state;
 143
 144 struct btrfsic_block {
 145         u32 magic_num;          /* only used for debug purposes */
 146         unsigned int is_metadata:1;     /* if it is meta-data, not data-data */
 147         unsigned int is_superblock:1;   /* if it is one of the superblocks */
 148         unsigned int is_iodone:1;       /* if is done by lower subsystem */
 149         unsigned int iodone_w_error:1;  /* error was indicated to endio */
 150         unsigned int never_written:1;   /* block was added because it was
 151                                          * referenced, not because it was
 152                                          * written */
 153         unsigned int mirror_num;        /* large enough to hold
 154                                          * BTRFS_SUPER_MIRROR_MAX */
 155         struct btrfsic_dev_state *dev_state;
 156         u64 dev_bytenr;         /* key, physical byte num on disk */
 157         u64 logical_bytenr;     /* logical byte num on disk */
 158         u64 generation;
 159         struct btrfs_disk_key disk_key; /* extra info to print in case of
 160                                          * issues, will not always be correct */
 161         struct list_head collision_resolving_node;      /* list node */
 162         struct list_head all_blocks_node;       /* list node */
 163
 164         /* the following two lists contain block_link items */
 165         struct list_head ref_to_list;   /* list */
 166         struct list_head ref_from_list; /* list */
 167         struct btrfsic_block *next_in_same_bio;
 168         void *orig_bio_bh_private;
 169         union {
 170                 bio_end_io_t *bio;
 171                 bh_end_io_t *bh;
 172         } orig_bio_bh_end_io;
 173         int submit_bio_bh_rw;
 174         u64 flush_gen; /* only valid if !never_written */
 175 };
 176
 177 /*
 178  * Elements of this type are allocated dynamically and required because
 179  * each block object can refer to and can be ref from multiple blocks.
 180  * The key to lookup them in the hashtable is the dev_bytenr of
 181  * the block ref to plus the one from the block referred from.
 182  * The fact that they are searchable via a hashtable and that a
 183  * ref_cnt is maintained is not required for the btrfs integrity
 184  * check algorithm itself, it is only used to make the output more
 185  * beautiful in case that an error is detected (an error is defined
 186  * as a write operation to a block while that block is still referenced).
 187  */
 188 struct btrfsic_block_link {
 189         u32 magic_num;          /* only used for debug purposes */
 190         u32 ref_cnt;
 191         struct list_head node_ref_to;   /* list node */
 192         struct list_head node_ref_from; /* list node */
 193         struct list_head collision_resolving_node;      /* list node */
 194         struct btrfsic_block *block_ref_to;
 195         struct btrfsic_block *block_ref_from;
 196         u64 parent_generation;
 197 };
 198
 199 struct btrfsic_dev_state {
 200         u32 magic_num;          /* only used for debug purposes */
 201         struct block_device *bdev;
 202         struct btrfsic_state *state;
 203         struct list_head collision_resolving_node;      /* list node */
 204         struct btrfsic_block dummy_block_for_bio_bh_flush;
 205         u64 last_flush_gen;
 206         char name[BDEVNAME_SIZE];
 207 };
 208
 209 struct btrfsic_block_hashtable {
 210         struct list_head table[BTRFSIC_BLOCK_HASHTABLE_SIZE];
 211 };
 212
 213 struct btrfsic_block_link_hashtable {
 214         struct list_head table[BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE];
 215 };
 216
 217 struct btrfsic_dev_state_hashtable {
 218         struct list_head table[BTRFSIC_DEV2STATE_HASHTABLE_SIZE];
 219 };
 220
 221 struct btrfsic_block_data_ctx {
 222         u64 start;              /* virtual bytenr */
 223         u64 dev_bytenr;         /* physical bytenr on device */
 224         u32 len;
 225         struct btrfsic_dev_state *dev;
 226         char **datav;
 227         struct page **pagev;
 228         void *mem_to_free;
 229 };
 230
 231 /* This structure is used to implement recursion without occupying
 232  * any stack space, refer to btrfsic_process_metablock() */
 233 struct btrfsic_stack_frame {
 234         u32 magic;
 235         u32 nr;
 236         int error;
 237         int i;
 238         int limit_nesting;
 239         int num_copies;
 240         int mirror_num;
 241         struct btrfsic_block *block;
 242         struct btrfsic_block_data_ctx *block_ctx;
 243         struct btrfsic_block *next_block;
 244         struct btrfsic_block_data_ctx next_block_ctx;
 245         struct btrfs_header *hdr;
 246         struct btrfsic_stack_frame *prev;
 247 };
 248
 249 /* Some state per mounted filesystem */
 250 struct btrfsic_state {
 251         u32 print_mask;
 252         int include_extent_data;
 253         int csum_size;
 254         struct list_head all_blocks_list;
 255         struct btrfsic_block_hashtable block_hashtable;
 256         struct btrfsic_block_link_hashtable block_link_hashtable;
 257         struct btrfs_root *root;
 258         u64 max_superblock_generation;
 259         struct btrfsic_block *latest_superblock;
 260         u32 metablock_size;
 261         u32 datablock_size;
 262 };
 263
 264 static void btrfsic_block_init(struct btrfsic_block *b);
 265 static struct btrfsic_block *btrfsic_block_alloc(void);
 266 static void btrfsic_block_free(struct btrfsic_block *b);
 267 static void btrfsic_block_link_init(struct btrfsic_block_link *n);
 268 static struct btrfsic_block_link *btrfsic_block_link_alloc(void);
 269 static void btrfsic_block_link_free(struct btrfsic_block_link *n);
 270 static void btrfsic_dev_state_init(struct btrfsic_dev_state *ds);
 271 static struct btrfsic_dev_state *btrfsic_dev_state_alloc(void);
 272 static void btrfsic_dev_state_free(struct btrfsic_dev_state *ds);
 273 static void btrfsic_block_hashtable_init(struct btrfsic_block_hashtable *h);
 274 static void btrfsic_block_hashtable_add(struct btrfsic_block *b,
 275                                         struct btrfsic_block_hashtable *h);
 276 static void btrfsic_block_hashtable_remove(struct btrfsic_block *b);
 277 static struct btrfsic_block *btrfsic_block_hashtable_lookup(
 278                 struct block_device *bdev,
 279                 u64 dev_bytenr,
 280                 struct btrfsic_block_hashtable *h);
 281 static void btrfsic_block_link_hashtable_init(
 282                 struct btrfsic_block_link_hashtable *h);
 283 static void btrfsic_block_link_hashtable_add(
 284                 struct btrfsic_block_link *l,
 285                 struct btrfsic_block_link_hashtable *h);
 286 static void btrfsic_block_link_hashtable_remove(struct btrfsic_block_link *l);
 287 static struct btrfsic_block_link *btrfsic_block_link_hashtable_lookup(
 288                 struct block_device *bdev_ref_to,
 289                 u64 dev_bytenr_ref_to,
 290                 struct block_device *bdev_ref_from,
 291                 u64 dev_bytenr_ref_from,
 292                 struct btrfsic_block_link_hashtable *h);
 293 static void btrfsic_dev_state_hashtable_init(
 294                 struct btrfsic_dev_state_hashtable *h);
 295 static void btrfsic_dev_state_hashtable_add(
 296                 struct btrfsic_dev_state *ds,
 297                 struct btrfsic_dev_state_hashtable *h);
 298 static void btrfsic_dev_state_hashtable_remove(struct btrfsic_dev_state *ds);
 299 static struct btrfsic_dev_state *btrfsic_dev_state_hashtable_lookup(
 300                 struct block_device *bdev,
 301                 struct btrfsic_dev_state_hashtable *h);
 302 static struct btrfsic_stack_frame *btrfsic_stack_frame_alloc(void);
 303 static void btrfsic_stack_frame_free(struct btrfsic_stack_frame *sf);
 304 static int btrfsic_process_superblock(struct btrfsic_state *state,
 305                                       struct btrfs_fs_devices *fs_devices);
 306 static int btrfsic_process_metablock(struct btrfsic_state *state,
 307                                      struct btrfsic_block *block,
 308                                      struct btrfsic_block_data_ctx *block_ctx,
 309                                      int limit_nesting, int force_iodone_flag);
 310 static void btrfsic_read_from_block_data(
 311         struct btrfsic_block_data_ctx *block_ctx,
 312         void *dst, u32 offset, size_t len);
 313 static int btrfsic_create_link_to_next_block(
 314                 struct btrfsic_state *state,
 315                 struct btrfsic_block *block,
 316                 struct btrfsic_block_data_ctx
 317                 *block_ctx, u64 next_bytenr,
 318                 int limit_nesting,
 319                 struct btrfsic_block_data_ctx *next_block_ctx,
 320                 struct btrfsic_block **next_blockp,
 321                 int force_iodone_flag,
 322                 int *num_copiesp, int *mirror_nump,
 323                 struct btrfs_disk_key *disk_key,
 324                 u64 parent_generation);
 325 static int btrfsic_handle_extent_data(struct btrfsic_state *state,
 326                                       struct btrfsic_block *block,
 327                                       struct btrfsic_block_data_ctx *block_ctx,
 328                                       u32 item_offset, int force_iodone_flag);
 329 static int btrfsic_map_block(struct btrfsic_state *state, u64 bytenr, u32 len,
 330                              struct btrfsic_block_data_ctx *block_ctx_out,
 331                              int mirror_num);
 332 static void btrfsic_release_block_ctx(struct btrfsic_block_data_ctx *block_ctx);
 333 static int btrfsic_read_block(struct btrfsic_state *state,
 334                               struct btrfsic_block_data_ctx *block_ctx);
 335 static void btrfsic_dump_database(struct btrfsic_state *state);
 336 static int btrfsic_test_for_metadata(struct btrfsic_state *state,
 337                                      char **datav, unsigned int num_pages);
 338 static void btrfsic_process_written_block(struct btrfsic_dev_state *dev_state,
 339                                           u64 dev_bytenr, char **mapped_datav,
 340                                           unsigned int num_pages,
 341                                           struct bio *bio, int *bio_is_patched,
 342                                           struct buffer_head *bh,
 343                                           int submit_bio_bh_rw);
 344 static int btrfsic_process_written_superblock(
 345                 struct btrfsic_state *state,
 346                 struct btrfsic_block *const block,
 347                 struct btrfs_super_block *const super_hdr);
 348 static void btrfsic_bio_end_io(struct bio *bp);
 349 static void btrfsic_bh_end_io(struct buffer_head *bh, int uptodate);
 350 static int btrfsic_is_block_ref_by_superblock(const struct btrfsic_state *state,
 351                                               const struct btrfsic_block *block,
 352                                               int recursion_level);
 353 static int btrfsic_check_all_ref_blocks(struct btrfsic_state *state,
 354                                         struct btrfsic_block *const block,
 355                                         int recursion_level);
 356 static void btrfsic_print_add_link(const struct btrfsic_state *state,
 357                                    const struct btrfsic_block_link *l);
 358 static void btrfsic_print_rem_link(const struct btrfsic_state *state,
 359                                    const struct btrfsic_block_link *l);
 360 static char btrfsic_get_block_type(const struct btrfsic_state *state,
 361                                    const struct btrfsic_block *block);
 362 static void btrfsic_dump_tree(const struct btrfsic_state *state);
 363 static void btrfsic_dump_tree_sub(const struct btrfsic_state *state,
 364                                   const struct btrfsic_block *block,
 365                                   int indent_level);
 366 static struct btrfsic_block_link *btrfsic_block_link_lookup_or_add(
 367                 struct btrfsic_state *state,
 368                 struct btrfsic_block_data_ctx *next_block_ctx,
 369                 struct btrfsic_block *next_block,
 370                 struct btrfsic_block *from_block,
 371                 u64 parent_generation);
 372 static struct btrfsic_block *btrfsic_block_lookup_or_add(
 373                 struct btrfsic_state *state,
 374                 struct btrfsic_block_data_ctx *block_ctx,
 375                 const char *additional_string,
 376                 int is_metadata,
 377                 int is_iodone,
 378                 int never_written,
 379                 int mirror_num,
 380                 int *was_created);
 381 static int btrfsic_process_superblock_dev_mirror(
 382                 struct btrfsic_state *state,
 383                 struct btrfsic_dev_state *dev_state,
 384                 struct btrfs_device *device,
 385                 int superblock_mirror_num,
 386                 struct btrfsic_dev_state **selected_dev_state,
 387                 struct btrfs_super_block *selected_super);
 388 static struct btrfsic_dev_state *btrfsic_dev_state_lookup(
 389                 struct block_device *bdev);
 390 static void btrfsic_cmp_log_and_dev_bytenr(struct btrfsic_state *state,
 391                                            u64 bytenr,
 392                                            struct btrfsic_dev_state *dev_state,
 393                                            u64 dev_bytenr);
 394
 395 static struct mutex btrfsic_mutex;
 396 static int btrfsic_is_initialized;
 397 static struct btrfsic_dev_state_hashtable btrfsic_dev_state_hashtable;
 398
 399
 400 static void btrfsic_block_init(struct btrfsic_block *b)
 401 {
 402         b->magic_num = BTRFSIC_BLOCK_MAGIC_NUMBER;
 403         b->dev_state = NULL;
 404         b->dev_bytenr = 0;
 405         b->logical_bytenr = 0;
 406         b->generation = BTRFSIC_GENERATION_UNKNOWN;
 407         b->disk_key.objectid = 0;
 408         b->disk_key.type = 0;
 409         b->disk_key.offset = 0;
 410         b->is_metadata = 0;
 411         b->is_superblock = 0;
 412         b->is_iodone = 0;
 413         b->iodone_w_error = 0;
 414         b->never_written = 0;
 415         b->mirror_num = 0;
 416         b->next_in_same_bio = NULL;
 417         b->orig_bio_bh_private = NULL;
 418         b->orig_bio_bh_end_io.bio = NULL;
 419         INIT_LIST_HEAD(&b->collision_resolving_node);
 420         INIT_LIST_HEAD(&b->all_blocks_node);
 421         INIT_LIST_HEAD(&b->ref_to_list);
 422         INIT_LIST_HEAD(&b->ref_from_list);
 423         b->submit_bio_bh_rw = 0;
 424         b->flush_gen = 0;
 425 }
 426
 427 static struct btrfsic_block *btrfsic_block_alloc(void)
 428 {
 429         struct btrfsic_block *b;
 430
 431         b = kzalloc(sizeof(*b), GFP_NOFS);
 432         if (NULL != b)
 433                 btrfsic_block_init(b);
 434
 435         return b;
 436 }
 437
 438 static void btrfsic_block_free(struct btrfsic_block *b)
 439 {
 440         BUG_ON(!(NULL == b || BTRFSIC_BLOCK_MAGIC_NUMBER == b->magic_num));
 441         kfree(b);
 442 }
 443
 444 static void btrfsic_block_link_init(struct btrfsic_block_link *l)
 445 {
 446         l->magic_num = BTRFSIC_BLOCK_LINK_MAGIC_NUMBER;
 447         l->ref_cnt = 1;
 448         INIT_LIST_HEAD(&l->node_ref_to);
 449         INIT_LIST_HEAD(&l->node_ref_from);
 450         INIT_LIST_HEAD(&l->collision_resolving_node);
 451         l->block_ref_to = NULL;
 452         l->block_ref_from = NULL;
 453 }
 454
 455 static struct btrfsic_block_link *btrfsic_block_link_alloc(void)
 456 {
 457         struct btrfsic_block_link *l;
 458
 459         l = kzalloc(sizeof(*l), GFP_NOFS);
 460         if (NULL != l)
 461                 btrfsic_block_link_init(l);
 462
 463         return l;
 464 }
 465
 466 static void btrfsic_block_link_free(struct btrfsic_block_link *l)
 467 {
 468         BUG_ON(!(NULL == l || BTRFSIC_BLOCK_LINK_MAGIC_NUMBER == l->magic_num));
 469         kfree(l);
 470 }
 471
 472 static void btrfsic_dev_state_init(struct btrfsic_dev_state *ds)
 473 {
 474         ds->magic_num = BTRFSIC_DEV2STATE_MAGIC_NUMBER;
 475         ds->bdev = NULL;
 476         ds->state = NULL;
 477         ds->name[0] = '\0';
 478         INIT_LIST_HEAD(&ds->collision_resolving_node);
 479         ds->last_flush_gen = 0;
 480         btrfsic_block_init(&ds->dummy_block_for_bio_bh_flush);
 481         ds->dummy_block_for_bio_bh_flush.is_iodone = 1;
 482         ds->dummy_block_for_bio_bh_flush.dev_state = ds;
 483 }
 484
 485 static struct btrfsic_dev_state *btrfsic_dev_state_alloc(void)
 486 {
 487         struct btrfsic_dev_state *ds;
 488
 489         ds = kzalloc(sizeof(*ds), GFP_NOFS);
 490         if (NULL != ds)
 491                 btrfsic_dev_state_init(ds);
 492
 493         return ds;
 494 }
 495
 496 static void btrfsic_dev_state_free(struct btrfsic_dev_state *ds)
 497 {
 498         BUG_ON(!(NULL == ds ||
 499                  BTRFSIC_DEV2STATE_MAGIC_NUMBER == ds->magic_num));
 500         kfree(ds);
 501 }
 502
 503 static void btrfsic_block_hashtable_init(struct btrfsic_block_hashtable *h)
 504 {
 505         int i;
 506
 507         for (i = 0; i < BTRFSIC_BLOCK_HASHTABLE_SIZE; i++)
 508                 INIT_LIST_HEAD(h->table + i);
 509 }
 510
 511 static void btrfsic_block_hashtable_add(struct btrfsic_block *b,
 512                                         struct btrfsic_block_hashtable *h)
 513 {
 514         const unsigned int hashval =
 515             (((unsigned int)(b->dev_bytenr >> 16)) ^
 516              ((unsigned int)((uintptr_t)b->dev_state->bdev))) &
 517              (BTRFSIC_BLOCK_HASHTABLE_SIZE - 1);
 518
 519         list_add(&b->collision_resolving_node, h->table + hashval);
 520 }
 521
 522 static void btrfsic_block_hashtable_remove(struct btrfsic_block *b)
 523 {
 524         list_del(&b->collision_resolving_node);
 525 }
 526
 527 static struct btrfsic_block *btrfsic_block_hashtable_lookup(
 528                 struct block_device *bdev,
 529                 u64 dev_bytenr,
 530                 struct btrfsic_block_hashtable *h)
 531 {
 532         const unsigned int hashval =
 533             (((unsigned int)(dev_bytenr >> 16)) ^
 534              ((unsigned int)((uintptr_t)bdev))) &
 535              (BTRFSIC_BLOCK_HASHTABLE_SIZE - 1);
 536         struct btrfsic_block *b;
 537
 538         list_for_each_entry(b, h->table + hashval, collision_resolving_node) {
 539                 if (b->dev_state->bdev == bdev && b->dev_bytenr == dev_bytenr)
 540                         return b;
 541         }
 542
 543         return NULL;
 544 }
 545
 546 static void btrfsic_block_link_hashtable_init(
 547                 struct btrfsic_block_link_hashtable *h)
 548 {
 549         int i;
 550
 551         for (i = 0; i < BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE; i++)
 552                 INIT_LIST_HEAD(h->table + i);
 553 }
 554
 555 static void btrfsic_block_link_hashtable_add(
 556                 struct btrfsic_block_link *l,
 557                 struct btrfsic_block_link_hashtable *h)
 558 {
 559         const unsigned int hashval =
 560             (((unsigned int)(l->block_ref_to->dev_bytenr >> 16)) ^
 561              ((unsigned int)(l->block_ref_from->dev_bytenr >> 16)) ^
 562              ((unsigned int)((uintptr_t)l->block_ref_to->dev_state->bdev)) ^
 563              ((unsigned int)((uintptr_t)l->block_ref_from->dev_state->bdev)))
 564              & (BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE - 1);
 565
 566         BUG_ON(NULL == l->block_ref_to);
 567         BUG_ON(NULL == l->block_ref_from);
 568         list_add(&l->collision_resolving_node, h->table + hashval);
 569 }
 570
 571 static void btrfsic_block_link_hashtable_remove(struct btrfsic_block_link *l)
 572 {
 573         list_del(&l->collision_resolving_node);
 574 }
 575
 576 static struct btrfsic_block_link *btrfsic_block_link_hashtable_lookup(
 577                 struct block_device *bdev_ref_to,
 578                 u64 dev_bytenr_ref_to,
 579                 struct block_device *bdev_ref_from,
 580                 u64 dev_bytenr_ref_from,
 581                 struct btrfsic_block_link_hashtable *h)
 582 {
 583         const unsigned int hashval =
 584             (((unsigned int)(dev_bytenr_ref_to >> 16)) ^
 585              ((unsigned int)(dev_bytenr_ref_from >> 16)) ^
 586              ((unsigned int)((uintptr_t)bdev_ref_to)) ^
 587              ((unsigned int)((uintptr_t)bdev_ref_from))) &
 588              (BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE - 1);
 589         struct btrfsic_block_link *l;
 590
 591         list_for_each_entry(l, h->table + hashval, collision_resolving_node) {
 592                 BUG_ON(NULL == l->block_ref_to);
 593                 BUG_ON(NULL == l->block_ref_from);
 594                 if (l->block_ref_to->dev_state->bdev == bdev_ref_to &&
 595                     l->block_ref_to->dev_bytenr == dev_bytenr_ref_to &&
 596                     l->block_ref_from->dev_state->bdev == bdev_ref_from &&
 597                     l->block_ref_from->dev_bytenr == dev_bytenr_ref_from)
 598                         return l;
 599         }
 600
 601         return NULL;
 602 }
 603
 604 static void btrfsic_dev_state_hashtable_init(
 605                 struct btrfsic_dev_state_hashtable *h)
 606 {
 607         int i;
 608
 609         for (i = 0; i < BTRFSIC_DEV2STATE_HASHTABLE_SIZE; i++)
 610                 INIT_LIST_HEAD(h->table + i);
 611 }
 612
 613 static void btrfsic_dev_state_hashtable_add(
 614                 struct btrfsic_dev_state *ds,
 615                 struct btrfsic_dev_state_hashtable *h)
 616 {
 617         const unsigned int hashval =
 618             (((unsigned int)((uintptr_t)ds->bdev)) &
 619              (BTRFSIC_DEV2STATE_HASHTABLE_SIZE - 1));
 620
 621         list_add(&ds->collision_resolving_node, h->table + hashval);
 622 }
 623
 624 static void btrfsic_dev_state_hashtable_remove(struct btrfsic_dev_state *ds)
 625 {
 626         list_del(&ds->collision_resolving_node);
 627 }
 628
 629 static struct btrfsic_dev_state *btrfsic_dev_state_hashtable_lookup(
 630                 struct block_device *bdev,
 631                 struct btrfsic_dev_state_hashtable *h)
 632 {
 633         const unsigned int hashval =
 634             (((unsigned int)((uintptr_t)bdev)) &
 635              (BTRFSIC_DEV2STATE_HASHTABLE_SIZE - 1));
 636         struct btrfsic_dev_state *ds;
 637
 638         list_for_each_entry(ds, h->table + hashval, collision_resolving_node) {
 639                 if (ds->bdev == bdev)
 640                         return ds;
 641         }
 642
 643         return NULL;
 644 }
 645
 646 static int btrfsic_process_superblock(struct btrfsic_state *state,
 647                                       struct btrfs_fs_devices *fs_devices)
 648 {
 649         int ret = 0;
 650         struct btrfs_super_block *selected_super;
 651         struct list_head *dev_head = &fs_devices->devices;
 652         struct btrfs_device *device;
 653         struct btrfsic_dev_state *selected_dev_state = NULL;
 654         int pass;
 655
 656         BUG_ON(NULL == state);
 657         selected_super = kzalloc(sizeof(*selected_super), GFP_NOFS);
 658         if (NULL == selected_super) {
 659                 pr_info("btrfsic: error, kmalloc failed!\n");
 660                 return -ENOMEM;
 661         }
 662
 663         list_for_each_entry(device, dev_head, dev_list) {
 664                 int i;
 665                 struct btrfsic_dev_state *dev_state;
 666
 667                 if (!device->bdev || !device->name)
 668                         continue;
 669
 670                 dev_state = btrfsic_dev_state_lookup(device->bdev);
 671                 BUG_ON(NULL == dev_state);
 672                 for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
 673                         ret = btrfsic_process_superblock_dev_mirror(
 674                                         state, dev_state, device, i,
 675                                         &selected_dev_state, selected_super);
 676                         if (0 != ret && 0 == i) {
 677                                 kfree(selected_super);
 678                                 return ret;
 679                         }
 680                 }
 681         }
 682
 683         if (NULL == state->latest_superblock) {
 684                 pr_info("btrfsic: no superblock found!\n");
 685                 kfree(selected_super);
 686                 return -1;
 687         }
 688
 689         state->csum_size = btrfs_super_csum_size(selected_super);
 690
 691         for (pass = 0; pass < 3; pass++) {
 692                 int num_copies;
 693                 int mirror_num;
 694                 u64 next_bytenr;
 695
 696                 switch (pass) {
 697                 case 0:
 698                         next_bytenr = btrfs_super_root(selected_super);
 699                         if (state->print_mask &
 700                             BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
 701                                 pr_info("root@%llu\n", next_bytenr);
 702                         break;
 703                 case 1:
 704                         next_bytenr = btrfs_super_chunk_root(selected_super);
 705                         if (state->print_mask &
 706                             BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
 707                                 pr_info("chunk@%llu\n", next_bytenr);
 708                         break;
 709                 case 2:
 710                         next_bytenr = btrfs_super_log_root(selected_super);
 711                         if (0 == next_bytenr)
 712                                 continue;
 713                         if (state->print_mask &
 714                             BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
 715                                 pr_info("log@%llu\n", next_bytenr);
 716                         break;
 717                 }
 718
 719                 num_copies =
 720                     btrfs_num_copies(state->root->fs_info,
 721                                      next_bytenr, state->metablock_size);
 722                 if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
 723                         pr_info("num_copies(log_bytenr=%llu) = %d\n",
 724                                next_bytenr, num_copies);
 725
 726                 for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
 727                         struct btrfsic_block *next_block;
 728                         struct btrfsic_block_data_ctx tmp_next_block_ctx;
 729                         struct btrfsic_block_link *l;
 730
 731                         ret = btrfsic_map_block(state, next_bytenr,
 732                                                 state->metablock_size,
 733                                                 &tmp_next_block_ctx,
 734                                                 mirror_num);
 735                         if (ret) {
 736                                 pr_info("btrfsic: btrfsic_map_block(root @%llu, mirror %d) failed!\n",
 737                                        next_bytenr, mirror_num);
 738                                 kfree(selected_super);
 739                                 return -1;
 740                         }
 741
 742                         next_block = btrfsic_block_hashtable_lookup(
 743                                         tmp_next_block_ctx.dev->bdev,
 744                                         tmp_next_block_ctx.dev_bytenr,
 745                                         &state->block_hashtable);
 746                         BUG_ON(NULL == next_block);
 747
 748                         l = btrfsic_block_link_hashtable_lookup(
 749                                         tmp_next_block_ctx.dev->bdev,
 750                                         tmp_next_block_ctx.dev_bytenr,
 751                                         state->latest_superblock->dev_state->
 752                                         bdev,
 753                                         state->latest_superblock->dev_bytenr,
 754                                         &state->block_link_hashtable);
 755                         BUG_ON(NULL == l);
 756
 757                         ret = btrfsic_read_block(state, &tmp_next_block_ctx);
 758                         if (ret < (int)PAGE_SIZE) {
 759                                 pr_info("btrfsic: read @logical %llu failed!\n",
 760                                        tmp_next_block_ctx.start);
 761                                 btrfsic_release_block_ctx(&tmp_next_block_ctx);
 762                                 kfree(selected_super);
 763                                 return -1;
 764                         }
 765
 766                         ret = btrfsic_process_metablock(state,
 767                                                         next_block,
 768                                                         &tmp_next_block_ctx,
 769                                                         BTRFS_MAX_LEVEL + 3, 1);
 770                         btrfsic_release_block_ctx(&tmp_next_block_ctx);
 771                 }
 772         }
 773
 774         kfree(selected_super);
 775         return ret;
 776 }
 777
 778 static int btrfsic_process_superblock_dev_mirror(
 779                 struct btrfsic_state *state,
 780                 struct btrfsic_dev_state *dev_state,
 781                 struct btrfs_device *device,
 782                 int superblock_mirror_num,
 783                 struct btrfsic_dev_state **selected_dev_state,
 784                 struct btrfs_super_block *selected_super)
 785 {
 786         struct btrfs_super_block *super_tmp;
 787         u64 dev_bytenr;
 788         struct buffer_head *bh;
 789         struct btrfsic_block *superblock_tmp;
 790         int pass;
 791         struct block_device *const superblock_bdev = device->bdev;
 792
 793         /* super block bytenr is always the unmapped device bytenr */
 794         dev_bytenr = btrfs_sb_offset(superblock_mirror_num);
 795         if (dev_bytenr + BTRFS_SUPER_INFO_SIZE > device->commit_total_bytes)
 796                 return -1;
 797         bh = __bread(superblock_bdev, dev_bytenr / 4096,
 798                      BTRFS_SUPER_INFO_SIZE);
 799         if (NULL == bh)
 800                 return -1;
 801         super_tmp = (struct btrfs_super_block *)
 802             (bh->b_data + (dev_bytenr & 4095));
 803
 804         if (btrfs_super_bytenr(super_tmp) != dev_bytenr ||
 805             btrfs_super_magic(super_tmp) != BTRFS_MAGIC ||
 806             memcmp(device->uuid, super_tmp->dev_item.uuid, BTRFS_UUID_SIZE) ||
 807             btrfs_super_nodesize(super_tmp) != state->metablock_size ||
 808             btrfs_super_sectorsize(super_tmp) != state->datablock_size) {
 809                 brelse(bh);
 810                 return 0;
 811         }
 812
 813         superblock_tmp =
 814             btrfsic_block_hashtable_lookup(superblock_bdev,
 815                                            dev_bytenr,
 816                                            &state->block_hashtable);
 817         if (NULL == superblock_tmp) {
 818                 superblock_tmp = btrfsic_block_alloc();
 819                 if (NULL == superblock_tmp) {
 820                         pr_info("btrfsic: error, kmalloc failed!\n");
 821                         brelse(bh);
 822                         return -1;
 823                 }
 824                 /* for superblock, only the dev_bytenr makes sense */
 825                 superblock_tmp->dev_bytenr = dev_bytenr;
 826                 superblock_tmp->dev_state = dev_state;
 827                 superblock_tmp->logical_bytenr = dev_bytenr;
 828                 superblock_tmp->generation = btrfs_super_generation(super_tmp);
 829                 superblock_tmp->is_metadata = 1;
 830                 superblock_tmp->is_superblock = 1;
 831                 superblock_tmp->is_iodone = 1;
 832                 superblock_tmp->never_written = 0;
 833                 superblock_tmp->mirror_num = 1 + superblock_mirror_num;
 834                 if (state->print_mask & BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE)
 835                         btrfs_info_in_rcu(device->dev_root->fs_info,
 836                                 "new initial S-block (bdev %p, %s) @%llu (%s/%llu/%d)",
 837                                      superblock_bdev,
 838                                      rcu_str_deref(device->name), dev_bytenr,
 839                                      dev_state->name, dev_bytenr,
 840                                      superblock_mirror_num);
 841                 list_add(&superblock_tmp->all_blocks_node,
 842                          &state->all_blocks_list);
 843                 btrfsic_block_hashtable_add(superblock_tmp,
 844                                             &state->block_hashtable);
 845         }
 846
 847         /* select the one with the highest generation field */
 848         if (btrfs_super_generation(super_tmp) >
 849             state->max_superblock_generation ||
 850             0 == state->max_superblock_generation) {
 851                 memcpy(selected_super, super_tmp, sizeof(*selected_super));
 852                 *selected_dev_state = dev_state;
 853                 state->max_superblock_generation =
 854                     btrfs_super_generation(super_tmp);
 855                 state->latest_superblock = superblock_tmp;
 856         }
 857
 858         for (pass = 0; pass < 3; pass++) {
 859                 u64 next_bytenr;
 860                 int num_copies;
 861                 int mirror_num;
 862                 const char *additional_string = NULL;
 863                 struct btrfs_disk_key tmp_disk_key;
 864
 865                 tmp_disk_key.type = BTRFS_ROOT_ITEM_KEY;
 866                 tmp_disk_key.offset = 0;
 867                 switch (pass) {
 868                 case 0:
 869                         btrfs_set_disk_key_objectid(&tmp_disk_key,
 870                                                     BTRFS_ROOT_TREE_OBJECTID);
 871                         additional_string = "initial root ";
 872                         next_bytenr = btrfs_super_root(super_tmp);
 873                         break;
 874                 case 1:
 875                         btrfs_set_disk_key_objectid(&tmp_disk_key,
 876                                                     BTRFS_CHUNK_TREE_OBJECTID);
 877                         additional_string = "initial chunk ";
 878                         next_bytenr = btrfs_super_chunk_root(super_tmp);
 879                         break;
 880                 case 2:
 881                         btrfs_set_disk_key_objectid(&tmp_disk_key,
 882                                                     BTRFS_TREE_LOG_OBJECTID);
 883                         additional_string = "initial log ";
 884                         next_bytenr = btrfs_super_log_root(super_tmp);
 885                         if (0 == next_bytenr)
 886                                 continue;
 887                         break;
 888                 }
 889
 890                 num_copies =
 891                     btrfs_num_copies(state->root->fs_info,
 892                                      next_bytenr, state->metablock_size);
 893                 if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
 894                         pr_info("num_copies(log_bytenr=%llu) = %d\n",
 895                                next_bytenr, num_copies);
 896                 for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
 897                         struct btrfsic_block *next_block;
 898                         struct btrfsic_block_data_ctx tmp_next_block_ctx;
 899                         struct btrfsic_block_link *l;
 900
 901                         if (btrfsic_map_block(state, next_bytenr,
 902                                               state->metablock_size,
 903                                               &tmp_next_block_ctx,
 904                                               mirror_num)) {
 905                                 pr_info("btrfsic: btrfsic_map_block(bytenr @%llu, mirror %d) failed!\n",
 906                                        next_bytenr, mirror_num);
 907                                 brelse(bh);
 908                                 return -1;
 909                         }
 910
 911                         next_block = btrfsic_block_lookup_or_add(
 912                                         state, &tmp_next_block_ctx,
 913                                         additional_string, 1, 1, 0,
 914                                         mirror_num, NULL);
 915                         if (NULL == next_block) {
 916                                 btrfsic_release_block_ctx(&tmp_next_block_ctx);
 917                                 brelse(bh);
 918                                 return -1;
 919                         }
 920
 921                         next_block->disk_key = tmp_disk_key;
 922                         next_block->generation = BTRFSIC_GENERATION_UNKNOWN;
 923                         l = btrfsic_block_link_lookup_or_add(
 924                                         state, &tmp_next_block_ctx,
 925                                         next_block, superblock_tmp,
 926                                         BTRFSIC_GENERATION_UNKNOWN);
 927                         btrfsic_release_block_ctx(&tmp_next_block_ctx);
 928                         if (NULL == l) {
 929                                 brelse(bh);
 930                                 return -1;
 931                         }
 932                 }
 933         }
 934         if (state->print_mask & BTRFSIC_PRINT_MASK_INITIAL_ALL_TREES)
 935                 btrfsic_dump_tree_sub(state, superblock_tmp, 0);
 936
 937         brelse(bh);
 938         return 0;
 939 }
 940
 941 static struct btrfsic_stack_frame *btrfsic_stack_frame_alloc(void)
 942 {
 943         struct btrfsic_stack_frame *sf;
 944
 945         sf = kzalloc(sizeof(*sf), GFP_NOFS);
 946         if (NULL == sf)
 947                 pr_info("btrfsic: alloc memory failed!\n");
 948         else
 949                 sf->magic = BTRFSIC_BLOCK_STACK_FRAME_MAGIC_NUMBER;
 950         return sf;
 951 }
 952
 953 static void btrfsic_stack_frame_free(struct btrfsic_stack_frame *sf)
 954 {
 955         BUG_ON(!(NULL == sf ||
 956                  BTRFSIC_BLOCK_STACK_FRAME_MAGIC_NUMBER == sf->magic));
 957         kfree(sf);
 958 }
 959
 960 static int btrfsic_process_metablock(
 961                 struct btrfsic_state *state,
 962                 struct btrfsic_block *const first_block,
 963                 struct btrfsic_block_data_ctx *const first_block_ctx,
 964                 int first_limit_nesting, int force_iodone_flag)
 965 {
 966         struct btrfsic_stack_frame initial_stack_frame = { 0 };
 967         struct btrfsic_stack_frame *sf;
 968         struct btrfsic_stack_frame *next_stack;
 969         struct btrfs_header *const first_hdr =
 970                 (struct btrfs_header *)first_block_ctx->datav[0];
 971
 972         BUG_ON(!first_hdr);
 973         sf = &initial_stack_frame;
 974         sf->error = 0;
 975         sf->i = -1;
 976         sf->limit_nesting = first_limit_nesting;
 977         sf->block = first_block;
 978         sf->block_ctx = first_block_ctx;
 979         sf->next_block = NULL;
 980         sf->hdr = first_hdr;
 981         sf->prev = NULL;
 982
 983 continue_with_new_stack_frame:
 984         sf->block->generation = le64_to_cpu(sf->hdr->generation);
 985         if (0 == sf->hdr->level) {
 986                 struct btrfs_leaf *const leafhdr =
 987                     (struct btrfs_leaf *)sf->hdr;
 988
 989                 if (-1 == sf->i) {
 990                         sf->nr = btrfs_stack_header_nritems(&leafhdr->header);
 991
 992                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
 993                                 pr_info("leaf %llu items %d generation %llu owner %llu\n",
 994                                        sf->block_ctx->start, sf->nr,
 995                                        btrfs_stack_header_generation(
 996                                                &leafhdr->header),
 997                                        btrfs_stack_header_owner(
 998                                                &leafhdr->header));
 999                 }
1000
1001 continue_with_current_leaf_stack_frame:
1002                 if (0 == sf->num_copies || sf->mirror_num > sf->num_copies) {
1003                         sf->i++;
1004                         sf->num_copies = 0;
1005                 }
1006
1007                 if (sf->i < sf->nr) {
1008                         struct btrfs_item disk_item;
1009                         u32 disk_item_offset =
1010                                 (uintptr_t)(leafhdr->items + sf->i) -
1011                                 (uintptr_t)leafhdr;
1012                         struct btrfs_disk_key *disk_key;
1013                         u8 type;
1014                         u32 item_offset;
1015                         u32 item_size;
1016
1017                         if (disk_item_offset + sizeof(struct btrfs_item) >
1018                             sf->block_ctx->len) {
1019 leaf_item_out_of_bounce_error:
1020                                 pr_info("btrfsic: leaf item out of bounce at logical %llu, dev %s\n",
1021                                        sf->block_ctx->start,
1022                                        sf->block_ctx->dev->name);
1023                                 goto one_stack_frame_backwards;
1024                         }
1025                         btrfsic_read_from_block_data(sf->block_ctx,
1026                                                      &disk_item,
1027                                                      disk_item_offset,
1028                                                      sizeof(struct btrfs_item));
1029                         item_offset = btrfs_stack_item_offset(&disk_item);
1030                         item_size = btrfs_stack_item_size(&disk_item);
1031                         disk_key = &disk_item.key;
1032                         type = btrfs_disk_key_type(disk_key);
1033
1034                         if (BTRFS_ROOT_ITEM_KEY == type) {
1035                                 struct btrfs_root_item root_item;
1036                                 u32 root_item_offset;
1037                                 u64 next_bytenr;
1038
1039                                 root_item_offset = item_offset +
1040                                         offsetof(struct btrfs_leaf, items);
1041                                 if (root_item_offset + item_size >
1042                                     sf->block_ctx->len)
1043                                         goto leaf_item_out_of_bounce_error;
1044                                 btrfsic_read_from_block_data(
1045                                         sf->block_ctx, &root_item,
1046                                         root_item_offset,
1047                                         item_size);
1048                                 next_bytenr = btrfs_root_bytenr(&root_item);
1049
1050                                 sf->error =
1051                                     btrfsic_create_link_to_next_block(
1052                                                 state,
1053                                                 sf->block,
1054                                                 sf->block_ctx,
1055                                                 next_bytenr,
1056                                                 sf->limit_nesting,
1057                                                 &sf->next_block_ctx,
1058                                                 &sf->next_block,
1059                                                 force_iodone_flag,
1060                                                 &sf->num_copies,
1061                                                 &sf->mirror_num,
1062                                                 disk_key,
1063                                                 btrfs_root_generation(
1064                                                 &root_item));
1065                                 if (sf->error)
1066                                         goto one_stack_frame_backwards;
1067
1068                                 if (NULL != sf->next_block) {
1069                                         struct btrfs_header *const next_hdr =
1070                                             (struct btrfs_header *)
1071                                             sf->next_block_ctx.datav[0];
1072
1073                                         next_stack =
1074                                             btrfsic_stack_frame_alloc();
1075                                         if (NULL == next_stack) {
1076                                                 sf->error = -1;
1077                                                 btrfsic_release_block_ctx(
1078                                                                 &sf->
1079                                                                 next_block_ctx);
1080                                                 goto one_stack_frame_backwards;
1081                                         }
1082
1083                                         next_stack->i = -1;
1084                                         next_stack->block = sf->next_block;
1085                                         next_stack->block_ctx =
1086                                             &sf->next_block_ctx;
1087                                         next_stack->next_block = NULL;
1088                                         next_stack->hdr = next_hdr;
1089                                         next_stack->limit_nesting =
1090                                             sf->limit_nesting - 1;
1091                                         next_stack->prev = sf;
1092                                         sf = next_stack;
1093                                         goto continue_with_new_stack_frame;
1094                                 }
1095                         } else if (BTRFS_EXTENT_DATA_KEY == type &&
1096                                    state->include_extent_data) {
1097                                 sf->error = btrfsic_handle_extent_data(
1098                                                 state,
1099                                                 sf->block,
1100                                                 sf->block_ctx,
1101                                                 item_offset,
1102                                                 force_iodone_flag);
1103                                 if (sf->error)
1104                                         goto one_stack_frame_backwards;
1105                         }
1106
1107                         goto continue_with_current_leaf_stack_frame;
1108                 }
1109         } else {
1110                 struct btrfs_node *const nodehdr = (struct btrfs_node *)sf->hdr;
1111
1112                 if (-1 == sf->i) {
1113                         sf->nr = btrfs_stack_header_nritems(&nodehdr->header);
1114
1115                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1116                                 pr_info("node %llu level %d items %d generation %llu owner %llu\n",
1117                                        sf->block_ctx->start,
1118                                        nodehdr->header.level, sf->nr,
1119                                        btrfs_stack_header_generation(
1120                                        &nodehdr->header),
1121                                        btrfs_stack_header_owner(
1122                                        &nodehdr->header));
1123                 }
1124
1125 continue_with_current_node_stack_frame:
1126                 if (0 == sf->num_copies || sf->mirror_num > sf->num_copies) {
1127                         sf->i++;
1128                         sf->num_copies = 0;
1129                 }
1130
1131                 if (sf->i < sf->nr) {
1132                         struct btrfs_key_ptr key_ptr;
1133                         u32 key_ptr_offset;
1134                         u64 next_bytenr;
1135
1136                         key_ptr_offset = (uintptr_t)(nodehdr->ptrs + sf->i) -
1137                                           (uintptr_t)nodehdr;
1138                         if (key_ptr_offset + sizeof(struct btrfs_key_ptr) >
1139                             sf->block_ctx->len) {
1140                                 pr_info("btrfsic: node item out of bounce at logical %llu, dev %s\n",
1141                                        sf->block_ctx->start,
1142                                        sf->block_ctx->dev->name);
1143                                 goto one_stack_frame_backwards;
1144                         }
1145                         btrfsic_read_from_block_data(
1146                                 sf->block_ctx, &key_ptr, key_ptr_offset,
1147                                 sizeof(struct btrfs_key_ptr));
1148                         next_bytenr = btrfs_stack_key_blockptr(&key_ptr);
1149
1150                         sf->error = btrfsic_create_link_to_next_block(
1151                                         state,
1152                                         sf->block,
1153                                         sf->block_ctx,
1154                                         next_bytenr,
1155                                         sf->limit_nesting,
1156                                         &sf->next_block_ctx,
1157                                         &sf->next_block,
1158                                         force_iodone_flag,
1159                                         &sf->num_copies,
1160                                         &sf->mirror_num,
1161                                         &key_ptr.key,
1162                                         btrfs_stack_key_generation(&key_ptr));
1163                         if (sf->error)
1164                                 goto one_stack_frame_backwards;
1165
1166                         if (NULL != sf->next_block) {
1167                                 struct btrfs_header *const next_hdr =
1168                                     (struct btrfs_header *)
1169                                     sf->next_block_ctx.datav[0];
1170
1171                                 next_stack = btrfsic_stack_frame_alloc();
1172                                 if (NULL == next_stack) {
1173                                         sf->error = -1;
1174                                         goto one_stack_frame_backwards;
1175                                 }
1176
1177                                 next_stack->i = -1;
1178                                 next_stack->block = sf->next_block;
1179                                 next_stack->block_ctx = &sf->next_block_ctx;
1180                                 next_stack->next_block = NULL;
1181                                 next_stack->hdr = next_hdr;
1182                                 next_stack->limit_nesting =
1183                                     sf->limit_nesting - 1;
1184                                 next_stack->prev = sf;
1185                                 sf = next_stack;
1186                                 goto continue_with_new_stack_frame;
1187                         }
1188
1189                         goto continue_with_current_node_stack_frame;
1190                 }
1191         }
1192
1193 one_stack_frame_backwards:
1194         if (NULL != sf->prev) {
1195                 struct btrfsic_stack_frame *const prev = sf->prev;
1196
1197                 /* the one for the initial block is freed in the caller */
1198                 btrfsic_release_block_ctx(sf->block_ctx);
1199
1200                 if (sf->error) {
1201                         prev->error = sf->error;
1202                         btrfsic_stack_frame_free(sf);
1203                         sf = prev;
1204                         goto one_stack_frame_backwards;
1205                 }
1206
1207                 btrfsic_stack_frame_free(sf);
1208                 sf = prev;
1209                 goto continue_with_new_stack_frame;
1210         } else {
1211                 BUG_ON(&initial_stack_frame != sf);
1212         }
1213
1214         return sf->error;
1215 }
1216
1217 static void btrfsic_read_from_block_data(
1218         struct btrfsic_block_data_ctx *block_ctx,
1219         void *dstv, u32 offset, size_t len)
1220 {
1221         size_t cur;
1222         size_t offset_in_page;
1223         char *kaddr;
1224         char *dst = (char *)dstv;
1225         size_t start_offset = block_ctx->start & ((u64)PAGE_SIZE - 1);
1226         unsigned long i = (start_offset + offset) >> PAGE_SHIFT;
1227
1228         WARN_ON(offset + len > block_ctx->len);
1229         offset_in_page = (start_offset + offset) & (PAGE_SIZE - 1);
1230
1231         while (len > 0) {
1232                 cur = min(len, ((size_t)PAGE_SIZE - offset_in_page));
1233                 BUG_ON(i >= DIV_ROUND_UP(block_ctx->len, PAGE_SIZE));
1234                 kaddr = block_ctx->datav[i];
1235                 memcpy(dst, kaddr + offset_in_page, cur);
1236
1237                 dst += cur;
1238                 len -= cur;
1239                 offset_in_page = 0;
1240                 i++;
1241         }
1242 }
1243
1244 static int btrfsic_create_link_to_next_block(
1245                 struct btrfsic_state *state,
1246                 struct btrfsic_block *block,
1247                 struct btrfsic_block_data_ctx *block_ctx,
1248                 u64 next_bytenr,
1249                 int limit_nesting,
1250                 struct btrfsic_block_data_ctx *next_block_ctx,
1251                 struct btrfsic_block **next_blockp,
1252                 int force_iodone_flag,
1253                 int *num_copiesp, int *mirror_nump,
1254                 struct btrfs_disk_key *disk_key,
1255                 u64 parent_generation)
1256 {
1257         struct btrfsic_block *next_block = NULL;
1258         int ret;
1259         struct btrfsic_block_link *l;
1260         int did_alloc_block_link;
1261         int block_was_created;
1262
1263         *next_blockp = NULL;
1264         if (0 == *num_copiesp) {
1265                 *num_copiesp =
1266                     btrfs_num_copies(state->root->fs_info,
1267                                      next_bytenr, state->metablock_size);
1268                 if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
1269                         pr_info("num_copies(log_bytenr=%llu) = %d\n",
1270                                next_bytenr, *num_copiesp);
1271                 *mirror_nump = 1;
1272         }
1273
1274         if (*mirror_nump > *num_copiesp)
1275                 return 0;
1276
1277         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1278                 pr_info("btrfsic_create_link_to_next_block(mirror_num=%d)\n",
1279                        *mirror_nump);
1280         ret = btrfsic_map_block(state, next_bytenr,
1281                                 state->metablock_size,
1282                                 next_block_ctx, *mirror_nump);
1283         if (ret) {
1284                 pr_info("btrfsic: btrfsic_map_block(@%llu, mirror=%d) failed!\n",
1285                        next_bytenr, *mirror_nump);
1286                 btrfsic_release_block_ctx(next_block_ctx);
1287                 *next_blockp = NULL;
1288                 return -1;
1289         }
1290
1291         next_block = btrfsic_block_lookup_or_add(state,
1292                                                  next_block_ctx, "referenced ",
1293                                                  1, force_iodone_flag,
1294                                                  !force_iodone_flag,
1295                                                  *mirror_nump,
1296                                                  &block_was_created);
1297         if (NULL == next_block) {
1298                 btrfsic_release_block_ctx(next_block_ctx);
1299                 *next_blockp = NULL;
1300                 return -1;
1301         }
1302         if (block_was_created) {
1303                 l = NULL;
1304                 next_block->generation = BTRFSIC_GENERATION_UNKNOWN;
1305         } else {
1306                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE) {
1307                         if (next_block->logical_bytenr != next_bytenr &&
1308                             !(!next_block->is_metadata &&
1309                               0 == next_block->logical_bytenr))
1310                                 pr_info("Referenced block @%llu (%s/%llu/%d) found in hash table, %c, bytenr mismatch (!= stored %llu).\n",
1311                                        next_bytenr, next_block_ctx->dev->name,
1312                                        next_block_ctx->dev_bytenr, *mirror_nump,
1313                                        btrfsic_get_block_type(state,
1314                                                               next_block),
1315                                        next_block->logical_bytenr);
1316                         else
1317                                 pr_info("Referenced block @%llu (%s/%llu/%d) found in hash table, %c.\n",
1318                                        next_bytenr, next_block_ctx->dev->name,
1319                                        next_block_ctx->dev_bytenr, *mirror_nump,
1320                                        btrfsic_get_block_type(state,
1321                                                               next_block));
1322                 }
1323                 next_block->logical_bytenr = next_bytenr;
1324
1325                 next_block->mirror_num = *mirror_nump;
1326                 l = btrfsic_block_link_hashtable_lookup(
1327                                 next_block_ctx->dev->bdev,
1328                                 next_block_ctx->dev_bytenr,
1329                                 block_ctx->dev->bdev,
1330                                 block_ctx->dev_bytenr,
1331                                 &state->block_link_hashtable);
1332         }
1333
1334         next_block->disk_key = *disk_key;
1335         if (NULL == l) {
1336                 l = btrfsic_block_link_alloc();
1337                 if (NULL == l) {
1338                         pr_info("btrfsic: error, kmalloc failed!\n");
1339                         btrfsic_release_block_ctx(next_block_ctx);
1340                         *next_blockp = NULL;
1341                         return -1;
1342                 }
1343
1344                 did_alloc_block_link = 1;
1345                 l->block_ref_to = next_block;
1346                 l->block_ref_from = block;
1347                 l->ref_cnt = 1;
1348                 l->parent_generation = parent_generation;
1349
1350                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1351                         btrfsic_print_add_link(state, l);
1352
1353                 list_add(&l->node_ref_to, &block->ref_to_list);
1354                 list_add(&l->node_ref_from, &next_block->ref_from_list);
1355
1356                 btrfsic_block_link_hashtable_add(l,
1357                                                  &state->block_link_hashtable);
1358         } else {
1359                 did_alloc_block_link = 0;
1360                 if (0 == limit_nesting) {
1361                         l->ref_cnt++;
1362                         l->parent_generation = parent_generation;
1363                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1364                                 btrfsic_print_add_link(state, l);
1365                 }
1366         }
1367
1368         if (limit_nesting > 0 && did_alloc_block_link) {
1369                 ret = btrfsic_read_block(state, next_block_ctx);
1370                 if (ret < (int)next_block_ctx->len) {
1371                         pr_info("btrfsic: read block @logical %llu failed!\n",
1372                                next_bytenr);
1373                         btrfsic_release_block_ctx(next_block_ctx);
1374                         *next_blockp = NULL;
1375                         return -1;
1376                 }
1377
1378                 *next_blockp = next_block;
1379         } else {
1380                 *next_blockp = NULL;
1381         }
1382         (*mirror_nump)++;
1383
1384         return 0;
1385 }
1386
1387 static int btrfsic_handle_extent_data(
1388                 struct btrfsic_state *state,
1389                 struct btrfsic_block *block,
1390                 struct btrfsic_block_data_ctx *block_ctx,
1391                 u32 item_offset, int force_iodone_flag)
1392 {
1393         int ret;
1394         struct btrfs_file_extent_item file_extent_item;
1395         u64 file_extent_item_offset;
1396         u64 next_bytenr;
1397         u64 num_bytes;
1398         u64 generation;
1399         struct btrfsic_block_link *l;
1400
1401         file_extent_item_offset = offsetof(struct btrfs_leaf, items) +
1402                                   item_offset;
1403         if (file_extent_item_offset +
1404             offsetof(struct btrfs_file_extent_item, disk_num_bytes) >
1405             block_ctx->len) {
1406                 pr_info("btrfsic: file item out of bounce at logical %llu, dev %s\n",
1407                        block_ctx->start, block_ctx->dev->name);
1408                 return -1;
1409         }
1410
1411         btrfsic_read_from_block_data(block_ctx, &file_extent_item,
1412                 file_extent_item_offset,
1413                 offsetof(struct btrfs_file_extent_item, disk_num_bytes));
1414         if (BTRFS_FILE_EXTENT_REG != file_extent_item.type ||
1415             btrfs_stack_file_extent_disk_bytenr(&file_extent_item) == 0) {
1416                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERY_VERBOSE)
1417                         pr_info("extent_data: type %u, disk_bytenr = %llu\n",
1418                                file_extent_item.type,
1419                                btrfs_stack_file_extent_disk_bytenr(
1420                                &file_extent_item));
1421                 return 0;
1422         }
1423
1424         if (file_extent_item_offset + sizeof(struct btrfs_file_extent_item) >
1425             block_ctx->len) {
1426                 pr_info("btrfsic: file item out of bounce at logical %llu, dev %s\n",
1427                        block_ctx->start, block_ctx->dev->name);
1428                 return -1;
1429         }
1430         btrfsic_read_from_block_data(block_ctx, &file_extent_item,
1431                                      file_extent_item_offset,
1432                                      sizeof(struct btrfs_file_extent_item));
1433         next_bytenr = btrfs_stack_file_extent_disk_bytenr(&file_extent_item);
1434         if (btrfs_stack_file_extent_compression(&file_extent_item) ==
1435             BTRFS_COMPRESS_NONE) {
1436                 next_bytenr += btrfs_stack_file_extent_offset(&file_extent_item);
1437                 num_bytes = btrfs_stack_file_extent_num_bytes(&file_extent_item);
1438         } else {
1439                 num_bytes = btrfs_stack_file_extent_disk_num_bytes(&file_extent_item);
1440         }
1441         generation = btrfs_stack_file_extent_generation(&file_extent_item);
1442
1443         if (state->print_mask & BTRFSIC_PRINT_MASK_VERY_VERBOSE)
1444                 pr_info("extent_data: type %u, disk_bytenr = %llu, offset = %llu, num_bytes = %llu\n",
1445                        file_extent_item.type,
1446                        btrfs_stack_file_extent_disk_bytenr(&file_extent_item),
1447                        btrfs_stack_file_extent_offset(&file_extent_item),
1448                        num_bytes);
1449         while (num_bytes > 0) {
1450                 u32 chunk_len;
1451                 int num_copies;
1452                 int mirror_num;
1453
1454                 if (num_bytes > state->datablock_size)
1455                         chunk_len = state->datablock_size;
1456                 else
1457                         chunk_len = num_bytes;
1458
1459                 num_copies =
1460                     btrfs_num_copies(state->root->fs_info,
1461                                      next_bytenr, state->datablock_size);
1462                 if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
1463                         pr_info("num_copies(log_bytenr=%llu) = %d\n",
1464                                next_bytenr, num_copies);
1465                 for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
1466                         struct btrfsic_block_data_ctx next_block_ctx;
1467                         struct btrfsic_block *next_block;
1468                         int block_was_created;
1469
1470                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1471                                 pr_info("btrfsic_handle_extent_data(mirror_num=%d)\n",
1472                                         mirror_num);
1473                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERY_VERBOSE)
1474                                 pr_info("\tdisk_bytenr = %llu, num_bytes %u\n",
1475                                        next_bytenr, chunk_len);
1476                         ret = btrfsic_map_block(state, next_bytenr,
1477                                                 chunk_len, &next_block_ctx,
1478                                                 mirror_num);
1479                         if (ret) {
1480                                 pr_info("btrfsic: btrfsic_map_block(@%llu, mirror=%d) failed!\n",
1481                                        next_bytenr, mirror_num);
1482                                 return -1;
1483                         }
1484
1485                         next_block = btrfsic_block_lookup_or_add(
1486                                         state,
1487                                         &next_block_ctx,
1488                                         "referenced ",
1489                                         0,
1490                                         force_iodone_flag,
1491                                         !force_iodone_flag,
1492                                         mirror_num,
1493                                         &block_was_created);
1494                         if (NULL == next_block) {
1495                                 pr_info("btrfsic: error, kmalloc failed!\n");
1496                                 btrfsic_release_block_ctx(&next_block_ctx);
1497                                 return -1;
1498                         }
1499                         if (!block_was_created) {
1500                                 if ((state->print_mask &
1501                                      BTRFSIC_PRINT_MASK_VERBOSE) &&
1502                                     next_block->logical_bytenr != next_bytenr &&
1503                                     !(!next_block->is_metadata &&
1504                                       0 == next_block->logical_bytenr)) {
1505                                         pr_info("Referenced block @%llu (%s/%llu/%d) found in hash table, D, bytenr mismatch (!= stored %llu).\n",
1506                                                next_bytenr,
1507                                                next_block_ctx.dev->name,
1508                                                next_block_ctx.dev_bytenr,
1509                                                mirror_num,
1510                                                next_block->logical_bytenr);
1511                                 }
1512                                 next_block->logical_bytenr = next_bytenr;
1513                                 next_block->mirror_num = mirror_num;
1514                         }
1515
1516                         l = btrfsic_block_link_lookup_or_add(state,
1517                                                              &next_block_ctx,
1518                                                              next_block, block,
1519                                                              generation);
1520                         btrfsic_release_block_ctx(&next_block_ctx);
1521                         if (NULL == l)
1522                                 return -1;
1523                 }
1524
1525                 next_bytenr += chunk_len;
1526                 num_bytes -= chunk_len;
1527         }
1528
1529         return 0;
1530 }
1531
1532 static int btrfsic_map_block(struct btrfsic_state *state, u64 bytenr, u32 len,
1533                              struct btrfsic_block_data_ctx *block_ctx_out,
1534                              int mirror_num)
1535 {
1536         int ret;
1537         u64 length;
1538         struct btrfs_bio *multi = NULL;
1539         struct btrfs_device *device;
1540
1541         length = len;
1542         ret = btrfs_map_block(state->root->fs_info, READ,
1543                               bytenr, &length, &multi, mirror_num);
1544
1545         if (ret) {
1546                 block_ctx_out->start = 0;
1547                 block_ctx_out->dev_bytenr = 0;
1548                 block_ctx_out->len = 0;
1549                 block_ctx_out->dev = NULL;
1550                 block_ctx_out->datav = NULL;
1551                 block_ctx_out->pagev = NULL;
1552                 block_ctx_out->mem_to_free = NULL;
1553
1554                 return ret;
1555         }
1556
1557         device = multi->stripes[0].dev;
1558         block_ctx_out->dev = btrfsic_dev_state_lookup(device->bdev);
1559         block_ctx_out->dev_bytenr = multi->stripes[0].physical;
1560         block_ctx_out->start = bytenr;
1561         block_ctx_out->len = len;
1562         block_ctx_out->datav = NULL;
1563         block_ctx_out->pagev = NULL;
1564         block_ctx_out->mem_to_free = NULL;
1565
1566         kfree(multi);
1567         if (NULL == block_ctx_out->dev) {
1568                 ret = -ENXIO;
1569                 pr_info("btrfsic: error, cannot lookup dev (#1)!\n");
1570         }
1571
1572         return ret;
1573 }
1574
1575 static void btrfsic_release_block_ctx(struct btrfsic_block_data_ctx *block_ctx)
1576 {
1577         if (block_ctx->mem_to_free) {
1578                 unsigned int num_pages;
1579
1580                 BUG_ON(!block_ctx->datav);
1581                 BUG_ON(!block_ctx->pagev);
1582                 num_pages = (block_ctx->len + (u64)PAGE_SIZE - 1) >>
1583                             PAGE_SHIFT;
1584                 while (num_pages > 0) {
1585                         num_pages--;
1586                         if (block_ctx->datav[num_pages]) {
1587                                 kunmap(block_ctx->pagev[num_pages]);
1588                                 block_ctx->datav[num_pages] = NULL;
1589                         }
1590                         if (block_ctx->pagev[num_pages]) {
1591                                 __free_page(block_ctx->pagev[num_pages]);
1592                                 block_ctx->pagev[num_pages] = NULL;
1593                         }
1594                 }
1595
1596                 kfree(block_ctx->mem_to_free);
1597                 block_ctx->mem_to_free = NULL;
1598                 block_ctx->pagev = NULL;
1599                 block_ctx->datav = NULL;
1600         }
1601 }
1602
1603 static int btrfsic_read_block(struct btrfsic_state *state,
1604                               struct btrfsic_block_data_ctx *block_ctx)
1605 {
1606         unsigned int num_pages;
1607         unsigned int i;
1608         u64 dev_bytenr;
1609         int ret;
1610
1611         BUG_ON(block_ctx->datav);
1612         BUG_ON(block_ctx->pagev);
1613         BUG_ON(block_ctx->mem_to_free);
1614         if (block_ctx->dev_bytenr & ((u64)PAGE_SIZE - 1)) {
1615                 pr_info("btrfsic: read_block() with unaligned bytenr %llu\n",
1616                        block_ctx->dev_bytenr);
1617                 return -1;
1618         }
1619
1620         num_pages = (block_ctx->len + (u64)PAGE_SIZE - 1) >>
1621                     PAGE_SHIFT;
1622         block_ctx->mem_to_free = kzalloc((sizeof(*block_ctx->datav) +
1623                                           sizeof(*block_ctx->pagev)) *
1624                                          num_pages, GFP_NOFS);
1625         if (!block_ctx->mem_to_free)
1626                 return -ENOMEM;
1627         block_ctx->datav = block_ctx->mem_to_free;
1628         block_ctx->pagev = (struct page **)(block_ctx->datav + num_pages);
1629         for (i = 0; i < num_pages; i++) {
1630                 block_ctx->pagev[i] = alloc_page(GFP_NOFS);
1631                 if (!block_ctx->pagev[i])
1632                         return -1;
1633         }
1634
1635         dev_bytenr = block_ctx->dev_bytenr;
1636         for (i = 0; i < num_pages;) {
1637                 struct bio *bio;
1638                 unsigned int j;
1639
1640                 bio = btrfs_io_bio_alloc(GFP_NOFS, num_pages - i);
1641                 if (!bio) {
1642                         pr_info("btrfsic: bio_alloc() for %u pages failed!\n",
1643                                num_pages - i);
1644                         return -1;
1645                 }
1646                 bio->bi_bdev = block_ctx->dev->bdev;
1647                 bio->bi_iter.bi_sector = dev_bytenr >> 9;
1648                 bio_set_op_attrs(bio, REQ_OP_READ, 0);
1649
1650                 for (j = i; j < num_pages; j++) {
1651                         ret = bio_add_page(bio, block_ctx->pagev[j],
1652                                            PAGE_SIZE, 0);
1653                         if (PAGE_SIZE != ret)
1654                                 break;
1655                 }
1656                 if (j == i) {
1657                         pr_info("btrfsic: error, failed to add a single page!\n");
1658                         return -1;
1659                 }
1660                 if (submit_bio_wait(bio)) {
1661                         pr_info("btrfsic: read error at logical %llu dev %s!\n",
1662                                block_ctx->start, block_ctx->dev->name);
1663                         bio_put(bio);
1664                         return -1;
1665                 }
1666                 bio_put(bio);
1667                 dev_bytenr += (j - i) * PAGE_SIZE;
1668                 i = j;
1669         }
1670         for (i = 0; i < num_pages; i++) {
1671                 block_ctx->datav[i] = kmap(block_ctx->pagev[i]);
1672                 if (!block_ctx->datav[i]) {
1673                         pr_info("btrfsic: kmap() failed (dev %s)!\n",
1674                                block_ctx->dev->name);
1675                         return -1;
1676                 }
1677         }
1678
1679         return block_ctx->len;
1680 }
1681
1682 static void btrfsic_dump_database(struct btrfsic_state *state)
1683 {
1684         const struct btrfsic_block *b_all;
1685
1686         BUG_ON(NULL == state);
1687
1688         pr_info("all_blocks_list:\n");
1689         list_for_each_entry(b_all, &state->all_blocks_list, all_blocks_node) {
1690                 const struct btrfsic_block_link *l;
1691
1692                 pr_info("%c-block @%llu (%s/%llu/%d)\n",
1693                        btrfsic_get_block_type(state, b_all),
1694                        b_all->logical_bytenr, b_all->dev_state->name,
1695                        b_all->dev_bytenr, b_all->mirror_num);
1696
1697                 list_for_each_entry(l, &b_all->ref_to_list, node_ref_to) {
1698                         pr_info(" %c @%llu (%s/%llu/%d) refers %u* to %c @%llu (%s/%llu/%d)\n",
1699                                btrfsic_get_block_type(state, b_all),
1700                                b_all->logical_bytenr, b_all->dev_state->name,
1701                                b_all->dev_bytenr, b_all->mirror_num,
1702                                l->ref_cnt,
1703                                btrfsic_get_block_type(state, l->block_ref_to),
1704                                l->block_ref_to->logical_bytenr,
1705                                l->block_ref_to->dev_state->name,
1706                                l->block_ref_to->dev_bytenr,
1707                                l->block_ref_to->mirror_num);
1708                 }
1709
1710                 list_for_each_entry(l, &b_all->ref_from_list, node_ref_from) {
1711                         pr_info(" %c @%llu (%s/%llu/%d) is ref %u* from %c @%llu (%s/%llu/%d)\n",
1712                                btrfsic_get_block_type(state, b_all),
1713                                b_all->logical_bytenr, b_all->dev_state->name,
1714                                b_all->dev_bytenr, b_all->mirror_num,
1715                                l->ref_cnt,
1716                                btrfsic_get_block_type(state, l->block_ref_from),
1717                                l->block_ref_from->logical_bytenr,
1718                                l->block_ref_from->dev_state->name,
1719                                l->block_ref_from->dev_bytenr,
1720                                l->block_ref_from->mirror_num);
1721                 }
1722
1723                 pr_info("\n");
1724         }
1725 }
1726
1727 /*
1728  * Test whether the disk block contains a tree block (leaf or node)
1729  * (note that this test fails for the super block)
1730  */
1731 static int btrfsic_test_for_metadata(struct btrfsic_state *state,
1732                                      char **datav, unsigned int num_pages)
1733 {
1734         struct btrfs_header *h;
1735         u8 csum[BTRFS_CSUM_SIZE];
1736         u32 crc = ~(u32)0;
1737         unsigned int i;
1738
1739         if (num_pages * PAGE_SIZE < state->metablock_size)
1740                 return 1; /* not metadata */
1741         num_pages = state->metablock_size >> PAGE_SHIFT;
1742         h = (struct btrfs_header *)datav[0];
1743
1744         if (memcmp(h->fsid, state->root->fs_info->fsid, BTRFS_UUID_SIZE))
1745                 return 1;
1746
1747         for (i = 0; i < num_pages; i++) {
1748                 u8 *data = i ? datav[i] : (datav[i] + BTRFS_CSUM_SIZE);
1749                 size_t sublen = i ? PAGE_SIZE :
1750                                     (PAGE_SIZE - BTRFS_CSUM_SIZE);
1751
1752                 crc = btrfs_crc32c(crc, data, sublen);
1753         }
1754         btrfs_csum_final(crc, csum);
1755         if (memcmp(csum, h->csum, state->csum_size))
1756                 return 1;
1757
1758         return 0; /* is metadata */
1759 }
1760
1761 static void btrfsic_process_written_block(struct btrfsic_dev_state *dev_state,
1762                                           u64 dev_bytenr, char **mapped_datav,
1763                                           unsigned int num_pages,
1764                                           struct bio *bio, int *bio_is_patched,
1765                                           struct buffer_head *bh,
1766                                           int submit_bio_bh_rw)
1767 {
1768         int is_metadata;
1769         struct btrfsic_block *block;
1770         struct btrfsic_block_data_ctx block_ctx;
1771         int ret;
1772         struct btrfsic_state *state = dev_state->state;
1773         struct block_device *bdev = dev_state->bdev;
1774         unsigned int processed_len;
1775
1776         if (NULL != bio_is_patched)
1777                 *bio_is_patched = 0;
1778
1779 again:
1780         if (num_pages == 0)
1781                 return;
1782
1783         processed_len = 0;
1784         is_metadata = (0 == btrfsic_test_for_metadata(state, mapped_datav,
1785                                                       num_pages));
1786
1787         block = btrfsic_block_hashtable_lookup(bdev, dev_bytenr,
1788                                                &state->block_hashtable);
1789         if (NULL != block) {
1790                 u64 bytenr = 0;
1791                 struct btrfsic_block_link *l, *tmp;
1792
1793                 if (block->is_superblock) {
1794                         bytenr = btrfs_super_bytenr((struct btrfs_super_block *)
1795                                                     mapped_datav[0]);
1796                         if (num_pages * PAGE_SIZE <
1797                             BTRFS_SUPER_INFO_SIZE) {
1798                                 pr_info("btrfsic: cannot work with too short bios!\n");
1799                                 return;
1800                         }
1801                         is_metadata = 1;
1802                         BUG_ON(BTRFS_SUPER_INFO_SIZE & (PAGE_SIZE - 1));
1803                         processed_len = BTRFS_SUPER_INFO_SIZE;
1804                         if (state->print_mask &
1805                             BTRFSIC_PRINT_MASK_TREE_BEFORE_SB_WRITE) {
1806                                 pr_info("[before new superblock is written]:\n");
1807                                 btrfsic_dump_tree_sub(state, block, 0);
1808                         }
1809                 }
1810                 if (is_metadata) {
1811                         if (!block->is_superblock) {
1812                                 if (num_pages * PAGE_SIZE <
1813                                     state->metablock_size) {
1814                                         pr_info("btrfsic: cannot work with too short bios!\n");
1815                                         return;
1816                                 }
1817                                 processed_len = state->metablock_size;
1818                                 bytenr = btrfs_stack_header_bytenr(
1819                                                 (struct btrfs_header *)
1820                                                 mapped_datav[0]);
1821                                 btrfsic_cmp_log_and_dev_bytenr(state, bytenr,
1822                                                                dev_state,
1823                                                                dev_bytenr);
1824                         }
1825                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE) {
1826                                 if (block->logical_bytenr != bytenr &&
1827                                     !(!block->is_metadata &&
1828                                       block->logical_bytenr == 0))
1829                                         pr_info("Written block @%llu (%s/%llu/%d) found in hash table, %c, bytenr mismatch (!= stored %llu).\n",
1830                                                bytenr, dev_state->name,
1831                                                dev_bytenr,
1832                                                block->mirror_num,
1833                                                btrfsic_get_block_type(state,
1834                                                                       block),
1835                                                block->logical_bytenr);
1836                                 else
1837                                         pr_info("Written block @%llu (%s/%llu/%d) found in hash table, %c.\n",
1838                                                bytenr, dev_state->name,
1839                                                dev_bytenr, block->mirror_num,
1840                                                btrfsic_get_block_type(state,
1841                                                                       block));
1842                         }
1843                         block->logical_bytenr = bytenr;
1844                 } else {
1845                         if (num_pages * PAGE_SIZE <
1846                             state->datablock_size) {
1847                                 pr_info("btrfsic: cannot work with too short bios!\n");
1848                                 return;
1849                         }
1850                         processed_len = state->datablock_size;
1851                         bytenr = block->logical_bytenr;
1852                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1853                                 pr_info("Written block @%llu (%s/%llu/%d) found in hash table, %c.\n",
1854                                        bytenr, dev_state->name, dev_bytenr,
1855                                        block->mirror_num,
1856                                        btrfsic_get_block_type(state, block));
1857                 }
1858
1859                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1860                         pr_info("ref_to_list: %cE, ref_from_list: %cE\n",
1861                                list_empty(&block->ref_to_list) ? ' ' : '!',
1862                                list_empty(&block->ref_from_list) ? ' ' : '!');
1863                 if (btrfsic_is_block_ref_by_superblock(state, block, 0)) {
1864                         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",
1865                                btrfsic_get_block_type(state, block), bytenr,
1866                                dev_state->name, dev_bytenr, block->mirror_num,
1867                                block->generation,
1868                                btrfs_disk_key_objectid(&block->disk_key),
1869                                block->disk_key.type,
1870                                btrfs_disk_key_offset(&block->disk_key),
1871                                btrfs_stack_header_generation(
1872                                        (struct btrfs_header *) mapped_datav[0]),
1873                                state->max_superblock_generation);
1874                         btrfsic_dump_tree(state);
1875                 }
1876
1877                 if (!block->is_iodone && !block->never_written) {
1878                         pr_info("btrfs: attempt to overwrite %c-block @%llu (%s/%llu/%d), oldgen=%llu, newgen=%llu, which is not yet iodone!\n",
1879                                btrfsic_get_block_type(state, block), bytenr,
1880                                dev_state->name, dev_bytenr, block->mirror_num,
1881                                block->generation,
1882                                btrfs_stack_header_generation(
1883                                        (struct btrfs_header *)
1884                                        mapped_datav[0]));
1885                         /* it would not be safe to go on */
1886                         btrfsic_dump_tree(state);
1887                         goto continue_loop;
1888                 }
1889
1890                 /*
1891                  * Clear all references of this block. Do not free
1892                  * the block itself even if is not referenced anymore
1893                  * because it still carries valuable information
1894                  * like whether it was ever written and IO completed.
1895                  */
1896                 list_for_each_entry_safe(l, tmp, &block->ref_to_list,
1897                                          node_ref_to) {
1898                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1899                                 btrfsic_print_rem_link(state, l);
1900                         l->ref_cnt--;
1901                         if (0 == l->ref_cnt) {
1902                                 list_del(&l->node_ref_to);
1903                                 list_del(&l->node_ref_from);
1904                                 btrfsic_block_link_hashtable_remove(l);
1905                                 btrfsic_block_link_free(l);
1906                         }
1907                 }
1908
1909                 block_ctx.dev = dev_state;
1910                 block_ctx.dev_bytenr = dev_bytenr;
1911                 block_ctx.start = bytenr;
1912                 block_ctx.len = processed_len;
1913                 block_ctx.pagev = NULL;
1914                 block_ctx.mem_to_free = NULL;
1915                 block_ctx.datav = mapped_datav;
1916
1917                 if (is_metadata || state->include_extent_data) {
1918                         block->never_written = 0;
1919                         block->iodone_w_error = 0;
1920                         if (NULL != bio) {
1921                                 block->is_iodone = 0;
1922                                 BUG_ON(NULL == bio_is_patched);
1923                                 if (!*bio_is_patched) {
1924                                         block->orig_bio_bh_private =
1925                                             bio->bi_private;
1926                                         block->orig_bio_bh_end_io.bio =
1927                                             bio->bi_end_io;
1928                                         block->next_in_same_bio = NULL;
1929                                         bio->bi_private = block;
1930                                         bio->bi_end_io = btrfsic_bio_end_io;
1931                                         *bio_is_patched = 1;
1932                                 } else {
1933                                         struct btrfsic_block *chained_block =
1934                                             (struct btrfsic_block *)
1935                                             bio->bi_private;
1936
1937                                         BUG_ON(NULL == chained_block);
1938                                         block->orig_bio_bh_private =
1939                                             chained_block->orig_bio_bh_private;
1940                                         block->orig_bio_bh_end_io.bio =
1941                                             chained_block->orig_bio_bh_end_io.
1942                                             bio;
1943                                         block->next_in_same_bio = chained_block;
1944                                         bio->bi_private = block;
1945                                 }
1946                         } else if (NULL != bh) {
1947                                 block->is_iodone = 0;
1948                                 block->orig_bio_bh_private = bh->b_private;
1949                                 block->orig_bio_bh_end_io.bh = bh->b_end_io;
1950                                 block->next_in_same_bio = NULL;
1951                                 bh->b_private = block;
1952                                 bh->b_end_io = btrfsic_bh_end_io;
1953                         } else {
1954                                 block->is_iodone = 1;
1955                                 block->orig_bio_bh_private = NULL;
1956                                 block->orig_bio_bh_end_io.bio = NULL;
1957                                 block->next_in_same_bio = NULL;
1958                         }
1959                 }
1960
1961                 block->flush_gen = dev_state->last_flush_gen + 1;
1962                 block->submit_bio_bh_rw = submit_bio_bh_rw;
1963                 if (is_metadata) {
1964                         block->logical_bytenr = bytenr;
1965                         block->is_metadata = 1;
1966                         if (block->is_superblock) {
1967                                 BUG_ON(PAGE_SIZE !=
1968                                        BTRFS_SUPER_INFO_SIZE);
1969                                 ret = btrfsic_process_written_superblock(
1970                                                 state,
1971                                                 block,
1972                                                 (struct btrfs_super_block *)
1973                                                 mapped_datav[0]);
1974                                 if (state->print_mask &
1975                                     BTRFSIC_PRINT_MASK_TREE_AFTER_SB_WRITE) {
1976                                         pr_info("[after new superblock is written]:\n");
1977                                         btrfsic_dump_tree_sub(state, block, 0);
1978                                 }
1979                         } else {
1980                                 block->mirror_num = 0;  /* unknown */
1981                                 ret = btrfsic_process_metablock(
1982                                                 state,
1983                                                 block,
1984                                                 &block_ctx,
1985                                                 0, 0);
1986                         }
1987                         if (ret)
1988                                 pr_info("btrfsic: btrfsic_process_metablock(root @%llu) failed!\n",
1989                                        dev_bytenr);
1990                 } else {
1991                         block->is_metadata = 0;
1992                         block->mirror_num = 0;  /* unknown */
1993                         block->generation = BTRFSIC_GENERATION_UNKNOWN;
1994                         if (!state->include_extent_data
1995                             && list_empty(&block->ref_from_list)) {
1996                                 /*
1997                                  * disk block is overwritten with extent
1998                                  * data (not meta data) and we are configured
1999                                  * to not include extent data: take the
2000                                  * chance and free the block's memory
2001                                  */
2002                                 btrfsic_block_hashtable_remove(block);
2003                                 list_del(&block->all_blocks_node);
2004                                 btrfsic_block_free(block);
2005                         }
2006                 }
2007                 btrfsic_release_block_ctx(&block_ctx);
2008         } else {
2009                 /* block has not been found in hash table */
2010                 u64 bytenr;
2011
2012                 if (!is_metadata) {
2013                         processed_len = state->datablock_size;
2014                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2015                                 pr_info("Written block (%s/%llu/?) !found in hash table, D.\n",
2016                                        dev_state->name, dev_bytenr);
2017                         if (!state->include_extent_data) {
2018                                 /* ignore that written D block */
2019                                 goto continue_loop;
2020                         }
2021
2022                         /* this is getting ugly for the
2023                          * include_extent_data case... */
2024                         bytenr = 0;     /* unknown */
2025                 } else {
2026                         processed_len = state->metablock_size;
2027                         bytenr = btrfs_stack_header_bytenr(
2028                                         (struct btrfs_header *)
2029                                         mapped_datav[0]);
2030                         btrfsic_cmp_log_and_dev_bytenr(state, bytenr, dev_state,
2031                                                        dev_bytenr);
2032                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2033                                 pr_info("Written block @%llu (%s/%llu/?) !found in hash table, M.\n",
2034                                        bytenr, dev_state->name, dev_bytenr);
2035                 }
2036
2037                 block_ctx.dev = dev_state;
2038                 block_ctx.dev_bytenr = dev_bytenr;
2039                 block_ctx.start = bytenr;
2040                 block_ctx.len = processed_len;
2041                 block_ctx.pagev = NULL;
2042                 block_ctx.mem_to_free = NULL;
2043                 block_ctx.datav = mapped_datav;
2044
2045                 block = btrfsic_block_alloc();
2046                 if (NULL == block) {
2047                         pr_info("btrfsic: error, kmalloc failed!\n");
2048                         btrfsic_release_block_ctx(&block_ctx);
2049                         goto continue_loop;
2050                 }
2051                 block->dev_state = dev_state;
2052                 block->dev_bytenr = dev_bytenr;
2053                 block->logical_bytenr = bytenr;
2054                 block->is_metadata = is_metadata;
2055                 block->never_written = 0;
2056                 block->iodone_w_error = 0;
2057                 block->mirror_num = 0;  /* unknown */
2058                 block->flush_gen = dev_state->last_flush_gen + 1;
2059                 block->submit_bio_bh_rw = submit_bio_bh_rw;
2060                 if (NULL != bio) {
2061                         block->is_iodone = 0;
2062                         BUG_ON(NULL == bio_is_patched);
2063                         if (!*bio_is_patched) {
2064                                 block->orig_bio_bh_private = bio->bi_private;
2065                                 block->orig_bio_bh_end_io.bio = bio->bi_end_io;
2066                                 block->next_in_same_bio = NULL;
2067                                 bio->bi_private = block;
2068                                 bio->bi_end_io = btrfsic_bio_end_io;
2069                                 *bio_is_patched = 1;
2070                         } else {
2071                                 struct btrfsic_block *chained_block =
2072                                     (struct btrfsic_block *)
2073                                     bio->bi_private;
2074
2075                                 BUG_ON(NULL == chained_block);
2076                                 block->orig_bio_bh_private =
2077                                     chained_block->orig_bio_bh_private;
2078                                 block->orig_bio_bh_end_io.bio =
2079                                     chained_block->orig_bio_bh_end_io.bio;
2080                                 block->next_in_same_bio = chained_block;
2081                                 bio->bi_private = block;
2082                         }
2083                 } else if (NULL != bh) {
2084                         block->is_iodone = 0;
2085                         block->orig_bio_bh_private = bh->b_private;
2086                         block->orig_bio_bh_end_io.bh = bh->b_end_io;
2087                         block->next_in_same_bio = NULL;
2088                         bh->b_private = block;
2089                         bh->b_end_io = btrfsic_bh_end_io;
2090                 } else {
2091                         block->is_iodone = 1;
2092                         block->orig_bio_bh_private = NULL;
2093                         block->orig_bio_bh_end_io.bio = NULL;
2094                         block->next_in_same_bio = NULL;
2095                 }
2096                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2097                         pr_info("New written %c-block @%llu (%s/%llu/%d)\n",
2098                                is_metadata ? 'M' : 'D',
2099                                block->logical_bytenr, block->dev_state->name,
2100                                block->dev_bytenr, block->mirror_num);
2101                 list_add(&block->all_blocks_node, &state->all_blocks_list);
2102                 btrfsic_block_hashtable_add(block, &state->block_hashtable);
2103
2104                 if (is_metadata) {
2105                         ret = btrfsic_process_metablock(state, block,
2106                                                         &block_ctx, 0, 0);
2107                         if (ret)
2108                                 pr_info("btrfsic: process_metablock(root @%llu) failed!\n",
2109                                        dev_bytenr);
2110                 }
2111                 btrfsic_release_block_ctx(&block_ctx);
2112         }
2113
2114 continue_loop:
2115         BUG_ON(!processed_len);
2116         dev_bytenr += processed_len;
2117         mapped_datav += processed_len >> PAGE_SHIFT;
2118         num_pages -= processed_len >> PAGE_SHIFT;
2119         goto again;
2120 }
2121
2122 static void btrfsic_bio_end_io(struct bio *bp)
2123 {
2124         struct btrfsic_block *block = (struct btrfsic_block *)bp->bi_private;
2125         int iodone_w_error;
2126
2127         /* mutex is not held! This is not save if IO is not yet completed
2128          * on umount */
2129         iodone_w_error = 0;
2130         if (bp->bi_error)
2131                 iodone_w_error = 1;
2132
2133         BUG_ON(NULL == block);
2134         bp->bi_private = block->orig_bio_bh_private;
2135         bp->bi_end_io = block->orig_bio_bh_end_io.bio;
2136
2137         do {
2138                 struct btrfsic_block *next_block;
2139                 struct btrfsic_dev_state *const dev_state = block->dev_state;
2140
2141                 if ((dev_state->state->print_mask &
2142                      BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2143                         pr_info("bio_end_io(err=%d) for %c @%llu (%s/%llu/%d)\n",
2144                                bp->bi_error,
2145                                btrfsic_get_block_type(dev_state->state, block),
2146                                block->logical_bytenr, dev_state->name,
2147                                block->dev_bytenr, block->mirror_num);
2148                 next_block = block->next_in_same_bio;
2149                 block->iodone_w_error = iodone_w_error;
2150                 if (block->submit_bio_bh_rw & REQ_PREFLUSH) {
2151                         dev_state->last_flush_gen++;
2152                         if ((dev_state->state->print_mask &
2153                              BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2154                                 pr_info("bio_end_io() new %s flush_gen=%llu\n",
2155                                        dev_state->name,
2156                                        dev_state->last_flush_gen);
2157                 }
2158                 if (block->submit_bio_bh_rw & REQ_FUA)
2159                         block->flush_gen = 0; /* FUA completed means block is
2160                                                * on disk */
2161                 block->is_iodone = 1; /* for FLUSH, this releases the block */
2162                 block = next_block;
2163         } while (NULL != block);
2164
2165         bp->bi_end_io(bp);
2166 }
2167
2168 static void btrfsic_bh_end_io(struct buffer_head *bh, int uptodate)
2169 {
2170         struct btrfsic_block *block = (struct btrfsic_block *)bh->b_private;
2171         int iodone_w_error = !uptodate;
2172         struct btrfsic_dev_state *dev_state;
2173
2174         BUG_ON(NULL == block);
2175         dev_state = block->dev_state;
2176         if ((dev_state->state->print_mask & BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2177                 pr_info("bh_end_io(error=%d) for %c @%llu (%s/%llu/%d)\n",
2178                        iodone_w_error,
2179                        btrfsic_get_block_type(dev_state->state, block),
2180                        block->logical_bytenr, block->dev_state->name,
2181                        block->dev_bytenr, block->mirror_num);
2182
2183         block->iodone_w_error = iodone_w_error;
2184         if (block->submit_bio_bh_rw & REQ_PREFLUSH) {
2185                 dev_state->last_flush_gen++;
2186                 if ((dev_state->state->print_mask &
2187                      BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2188                         pr_info("bh_end_io() new %s flush_gen=%llu\n",
2189                                dev_state->name, dev_state->last_flush_gen);
2190         }
2191         if (block->submit_bio_bh_rw & REQ_FUA)
2192                 block->flush_gen = 0; /* FUA completed means block is on disk */
2193
2194         bh->b_private = block->orig_bio_bh_private;
2195         bh->b_end_io = block->orig_bio_bh_end_io.bh;
2196         block->is_iodone = 1; /* for FLUSH, this releases the block */
2197         bh->b_end_io(bh, uptodate);
2198 }
2199
2200 static int btrfsic_process_written_superblock(
2201                 struct btrfsic_state *state,
2202                 struct btrfsic_block *const superblock,
2203                 struct btrfs_super_block *const super_hdr)
2204 {
2205         int pass;
2206
2207         superblock->generation = btrfs_super_generation(super_hdr);
2208         if (!(superblock->generation > state->max_superblock_generation ||
2209               0 == state->max_superblock_generation)) {
2210                 if (state->print_mask & BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE)
2211                         pr_info("btrfsic: superblock @%llu (%s/%llu/%d) with old gen %llu <= %llu\n",
2212                                superblock->logical_bytenr,
2213                                superblock->dev_state->name,
2214                                superblock->dev_bytenr, superblock->mirror_num,
2215                                btrfs_super_generation(super_hdr),
2216                                state->max_superblock_generation);
2217         } else {
2218                 if (state->print_mask & BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE)
2219                         pr_info("btrfsic: got new superblock @%llu (%s/%llu/%d) with new gen %llu > %llu\n",
2220                                superblock->logical_bytenr,
2221                                superblock->dev_state->name,
2222                                superblock->dev_bytenr, superblock->mirror_num,
2223                                btrfs_super_generation(super_hdr),
2224                                state->max_superblock_generation);
2225
2226                 state->max_superblock_generation =
2227                     btrfs_super_generation(super_hdr);
2228                 state->latest_superblock = superblock;
2229         }
2230
2231         for (pass = 0; pass < 3; pass++) {
2232                 int ret;
2233                 u64 next_bytenr;
2234                 struct btrfsic_block *next_block;
2235                 struct btrfsic_block_data_ctx tmp_next_block_ctx;
2236                 struct btrfsic_block_link *l;
2237                 int num_copies;
2238                 int mirror_num;
2239                 const char *additional_string = NULL;
2240                 struct btrfs_disk_key tmp_disk_key = {0};
2241
2242                 btrfs_set_disk_key_objectid(&tmp_disk_key,
2243                                             BTRFS_ROOT_ITEM_KEY);
2244                 btrfs_set_disk_key_objectid(&tmp_disk_key, 0);
2245
2246                 switch (pass) {
2247                 case 0:
2248                         btrfs_set_disk_key_objectid(&tmp_disk_key,
2249                                                     BTRFS_ROOT_TREE_OBJECTID);
2250                         additional_string = "root ";
2251                         next_bytenr = btrfs_super_root(super_hdr);
2252                         if (state->print_mask &
2253                             BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
2254                                 pr_info("root@%llu\n", next_bytenr);
2255                         break;
2256                 case 1:
2257                         btrfs_set_disk_key_objectid(&tmp_disk_key,
2258                                                     BTRFS_CHUNK_TREE_OBJECTID);
2259                         additional_string = "chunk ";
2260                         next_bytenr = btrfs_super_chunk_root(super_hdr);
2261                         if (state->print_mask &
2262                             BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
2263                                 pr_info("chunk@%llu\n", next_bytenr);
2264                         break;
2265                 case 2:
2266                         btrfs_set_disk_key_objectid(&tmp_disk_key,
2267                                                     BTRFS_TREE_LOG_OBJECTID);
2268                         additional_string = "log ";
2269                         next_bytenr = btrfs_super_log_root(super_hdr);
2270                         if (0 == next_bytenr)
2271                                 continue;
2272                         if (state->print_mask &
2273                             BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
2274                                 pr_info("log@%llu\n", next_bytenr);
2275                         break;
2276                 }
2277
2278                 num_copies =
2279                     btrfs_num_copies(state->root->fs_info,
2280                                      next_bytenr, BTRFS_SUPER_INFO_SIZE);
2281                 if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
2282                         pr_info("num_copies(log_bytenr=%llu) = %d\n",
2283                                next_bytenr, num_copies);
2284                 for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
2285                         int was_created;
2286
2287                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2288                                 pr_info("btrfsic_process_written_superblock(mirror_num=%d)\n", mirror_num);
2289                         ret = btrfsic_map_block(state, next_bytenr,
2290                                                 BTRFS_SUPER_INFO_SIZE,
2291                                                 &tmp_next_block_ctx,
2292                                                 mirror_num);
2293                         if (ret) {
2294                                 pr_info("btrfsic: btrfsic_map_block(@%llu, mirror=%d) failed!\n",
2295                                        next_bytenr, mirror_num);
2296                                 return -1;
2297                         }
2298
2299                         next_block = btrfsic_block_lookup_or_add(
2300                                         state,
2301                                         &tmp_next_block_ctx,
2302                                         additional_string,
2303                                         1, 0, 1,
2304                                         mirror_num,
2305                                         &was_created);
2306                         if (NULL == next_block) {
2307                                 pr_info("btrfsic: error, kmalloc failed!\n");
2308                                 btrfsic_release_block_ctx(&tmp_next_block_ctx);
2309                                 return -1;
2310                         }
2311
2312                         next_block->disk_key = tmp_disk_key;
2313                         if (was_created)
2314                                 next_block->generation =
2315                                     BTRFSIC_GENERATION_UNKNOWN;
2316                         l = btrfsic_block_link_lookup_or_add(
2317                                         state,
2318                                         &tmp_next_block_ctx,
2319                                         next_block,
2320                                         superblock,
2321                                         BTRFSIC_GENERATION_UNKNOWN);
2322                         btrfsic_release_block_ctx(&tmp_next_block_ctx);
2323                         if (NULL == l)
2324                                 return -1;
2325                 }
2326         }
2327
2328         if (WARN_ON(-1 == btrfsic_check_all_ref_blocks(state, superblock, 0)))
2329                 btrfsic_dump_tree(state);
2330
2331         return 0;
2332 }
2333
2334 static int btrfsic_check_all_ref_blocks(struct btrfsic_state *state,
2335                                         struct btrfsic_block *const block,
2336                                         int recursion_level)
2337 {
2338         const struct btrfsic_block_link *l;
2339         int ret = 0;
2340
2341         if (recursion_level >= 3 + BTRFS_MAX_LEVEL) {
2342                 /*
2343                  * Note that this situation can happen and does not
2344                  * indicate an error in regular cases. It happens
2345                  * when disk blocks are freed and later reused.
2346                  * The check-integrity module is not aware of any
2347                  * block free operations, it just recognizes block
2348                  * write operations. Therefore it keeps the linkage
2349                  * information for a block until a block is
2350                  * rewritten. This can temporarily cause incorrect
2351                  * and even circular linkage informations. This
2352                  * causes no harm unless such blocks are referenced
2353                  * by the most recent super block.
2354                  */
2355                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2356                         pr_info("btrfsic: abort cyclic linkage (case 1).\n");
2357
2358                 return ret;
2359         }
2360
2361         /*
2362          * This algorithm is recursive because the amount of used stack
2363          * space is very small and the max recursion depth is limited.
2364          */
2365         list_for_each_entry(l, &block->ref_to_list, node_ref_to) {
2366                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2367                         pr_info("rl=%d, %c @%llu (%s/%llu/%d) %u* refers to %c @%llu (%s/%llu/%d)\n",
2368                                recursion_level,
2369                                btrfsic_get_block_type(state, block),
2370                                block->logical_bytenr, block->dev_state->name,
2371                                block->dev_bytenr, block->mirror_num,
2372                                l->ref_cnt,
2373                                btrfsic_get_block_type(state, l->block_ref_to),
2374                                l->block_ref_to->logical_bytenr,
2375                                l->block_ref_to->dev_state->name,
2376                                l->block_ref_to->dev_bytenr,
2377                                l->block_ref_to->mirror_num);
2378                 if (l->block_ref_to->never_written) {
2379                         pr_info("btrfs: attempt to write superblock which references block %c @%llu (%s/%llu/%d) which is never written!\n",
2380                                btrfsic_get_block_type(state, l->block_ref_to),
2381                                l->block_ref_to->logical_bytenr,
2382                                l->block_ref_to->dev_state->name,
2383                                l->block_ref_to->dev_bytenr,
2384                                l->block_ref_to->mirror_num);
2385                         ret = -1;
2386                 } else if (!l->block_ref_to->is_iodone) {
2387                         pr_info("btrfs: attempt to write superblock which references block %c @%llu (%s/%llu/%d) which is not yet iodone!\n",
2388                                btrfsic_get_block_type(state, l->block_ref_to),
2389                                l->block_ref_to->logical_bytenr,
2390                                l->block_ref_to->dev_state->name,
2391                                l->block_ref_to->dev_bytenr,
2392                                l->block_ref_to->mirror_num);
2393                         ret = -1;
2394                 } else if (l->block_ref_to->iodone_w_error) {
2395                         pr_info("btrfs: attempt to write superblock which references block %c @%llu (%s/%llu/%d) which has write error!\n",
2396                                btrfsic_get_block_type(state, l->block_ref_to),
2397                                l->block_ref_to->logical_bytenr,
2398                                l->block_ref_to->dev_state->name,
2399                                l->block_ref_to->dev_bytenr,
2400                                l->block_ref_to->mirror_num);
2401                         ret = -1;
2402                 } else if (l->parent_generation !=
2403                            l->block_ref_to->generation &&
2404                            BTRFSIC_GENERATION_UNKNOWN !=
2405                            l->parent_generation &&
2406                            BTRFSIC_GENERATION_UNKNOWN !=
2407                            l->block_ref_to->generation) {
2408                         pr_info("btrfs: attempt to write superblock which references block %c @%llu (%s/%llu/%d) with generation %llu != parent generation %llu!\n",
2409                                btrfsic_get_block_type(state, l->block_ref_to),
2410                                l->block_ref_to->logical_bytenr,
2411                                l->block_ref_to->dev_state->name,
2412                                l->block_ref_to->dev_bytenr,
2413                                l->block_ref_to->mirror_num,
2414                                l->block_ref_to->generation,
2415                                l->parent_generation);
2416                         ret = -1;
2417                 } else if (l->block_ref_to->flush_gen >
2418                            l->block_ref_to->dev_state->last_flush_gen) {
2419                         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",
2420                                btrfsic_get_block_type(state, l->block_ref_to),
2421                                l->block_ref_to->logical_bytenr,
2422                                l->block_ref_to->dev_state->name,
2423                                l->block_ref_to->dev_bytenr,
2424                                l->block_ref_to->mirror_num, block->flush_gen,
2425                                l->block_ref_to->dev_state->last_flush_gen);
2426                         ret = -1;
2427                 } else if (-1 == btrfsic_check_all_ref_blocks(state,
2428                                                               l->block_ref_to,
2429                                                               recursion_level +
2430                                                               1)) {
2431                         ret = -1;
2432                 }
2433         }
2434
2435         return ret;
2436 }
2437
2438 static int btrfsic_is_block_ref_by_superblock(
2439                 const struct btrfsic_state *state,
2440                 const struct btrfsic_block *block,
2441                 int recursion_level)
2442 {
2443         const struct btrfsic_block_link *l;
2444
2445         if (recursion_level >= 3 + BTRFS_MAX_LEVEL) {
2446                 /* refer to comment at "abort cyclic linkage (case 1)" */
2447                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2448                         pr_info("btrfsic: abort cyclic linkage (case 2).\n");
2449
2450                 return 0;
2451         }
2452
2453         /*
2454          * This algorithm is recursive because the amount of used stack space
2455          * is very small and the max recursion depth is limited.
2456          */
2457         list_for_each_entry(l, &block->ref_from_list, node_ref_from) {
2458                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2459                         pr_info("rl=%d, %c @%llu (%s/%llu/%d) is ref %u* from %c @%llu (%s/%llu/%d)\n",
2460                                recursion_level,
2461                                btrfsic_get_block_type(state, block),
2462                                block->logical_bytenr, block->dev_state->name,
2463                                block->dev_bytenr, block->mirror_num,
2464                                l->ref_cnt,
2465                                btrfsic_get_block_type(state, l->block_ref_from),
2466                                l->block_ref_from->logical_bytenr,
2467                                l->block_ref_from->dev_state->name,
2468                                l->block_ref_from->dev_bytenr,
2469                                l->block_ref_from->mirror_num);
2470                 if (l->block_ref_from->is_superblock &&
2471                     state->latest_superblock->dev_bytenr ==
2472                     l->block_ref_from->dev_bytenr &&
2473                     state->latest_superblock->dev_state->bdev ==
2474                     l->block_ref_from->dev_state->bdev)
2475                         return 1;
2476                 else if (btrfsic_is_block_ref_by_superblock(state,
2477                                                             l->block_ref_from,
2478                                                             recursion_level +
2479                                                             1))
2480                         return 1;
2481         }
2482
2483         return 0;
2484 }
2485
2486 static void btrfsic_print_add_link(const struct btrfsic_state *state,
2487                                    const struct btrfsic_block_link *l)
2488 {
2489         pr_info("Add %u* link from %c @%llu (%s/%llu/%d) to %c @%llu (%s/%llu/%d).\n",
2490                l->ref_cnt,
2491                btrfsic_get_block_type(state, l->block_ref_from),
2492                l->block_ref_from->logical_bytenr,
2493                l->block_ref_from->dev_state->name,
2494                l->block_ref_from->dev_bytenr, l->block_ref_from->mirror_num,
2495                btrfsic_get_block_type(state, l->block_ref_to),
2496                l->block_ref_to->logical_bytenr,
2497                l->block_ref_to->dev_state->name, l->block_ref_to->dev_bytenr,
2498                l->block_ref_to->mirror_num);
2499 }
2500
2501 static void btrfsic_print_rem_link(const struct btrfsic_state *state,
2502                                    const struct btrfsic_block_link *l)
2503 {
2504         pr_info("Rem %u* link from %c @%llu (%s/%llu/%d) to %c @%llu (%s/%llu/%d).\n",
2505                l->ref_cnt,
2506                btrfsic_get_block_type(state, l->block_ref_from),
2507                l->block_ref_from->logical_bytenr,
2508                l->block_ref_from->dev_state->name,
2509                l->block_ref_from->dev_bytenr, l->block_ref_from->mirror_num,
2510                btrfsic_get_block_type(state, l->block_ref_to),
2511                l->block_ref_to->logical_bytenr,
2512                l->block_ref_to->dev_state->name, l->block_ref_to->dev_bytenr,
2513                l->block_ref_to->mirror_num);
2514 }
2515
2516 static char btrfsic_get_block_type(const struct btrfsic_state *state,
2517                                    const struct btrfsic_block *block)
2518 {
2519         if (block->is_superblock &&
2520             state->latest_superblock->dev_bytenr == block->dev_bytenr &&
2521             state->latest_superblock->dev_state->bdev == block->dev_state->bdev)
2522                 return 'S';
2523         else if (block->is_superblock)
2524                 return 's';
2525         else if (block->is_metadata)
2526                 return 'M';
2527         else
2528                 return 'D';
2529 }
2530
2531 static void btrfsic_dump_tree(const struct btrfsic_state *state)
2532 {
2533         btrfsic_dump_tree_sub(state, state->latest_superblock, 0);
2534 }
2535
2536 static void btrfsic_dump_tree_sub(const struct btrfsic_state *state,
2537                                   const struct btrfsic_block *block,
2538                                   int indent_level)
2539 {
2540         const struct btrfsic_block_link *l;
2541         int indent_add;
2542         static char buf[80];
2543         int cursor_position;
2544
2545         /*
2546          * Should better fill an on-stack buffer with a complete line and
2547          * dump it at once when it is time to print a newline character.
2548          */
2549
2550         /*
2551          * This algorithm is recursive because the amount of used stack space
2552          * is very small and the max recursion depth is limited.
2553          */
2554         indent_add = sprintf(buf, "%c-%llu(%s/%llu/%u)",
2555                              btrfsic_get_block_type(state, block),
2556                              block->logical_bytenr, block->dev_state->name,
2557                              block->dev_bytenr, block->mirror_num);
2558         if (indent_level + indent_add > BTRFSIC_TREE_DUMP_MAX_INDENT_LEVEL) {
2559                 printk("[...]\n");
2560                 return;
2561         }
2562         printk(buf);
2563         indent_level += indent_add;
2564         if (list_empty(&block->ref_to_list)) {
2565                 printk("\n");
2566                 return;
2567         }
2568         if (block->mirror_num > 1 &&
2569             !(state->print_mask & BTRFSIC_PRINT_MASK_TREE_WITH_ALL_MIRRORS)) {
2570                 printk(" [...]\n");
2571                 return;
2572         }
2573
2574         cursor_position = indent_level;
2575         list_for_each_entry(l, &block->ref_to_list, node_ref_to) {
2576                 while (cursor_position < indent_level) {
2577                         printk(" ");
2578                         cursor_position++;
2579                 }
2580                 if (l->ref_cnt > 1)
2581                         indent_add = sprintf(buf, " %d*--> ", l->ref_cnt);
2582                 else
2583                         indent_add = sprintf(buf, " --> ");
2584                 if (indent_level + indent_add >
2585                     BTRFSIC_TREE_DUMP_MAX_INDENT_LEVEL) {
2586                         printk("[...]\n");
2587                         cursor_position = 0;
2588                         continue;
2589                 }
2590
2591                 printk(buf);
2592
2593                 btrfsic_dump_tree_sub(state, l->block_ref_to,
2594                                       indent_level + indent_add);
2595                 cursor_position = 0;
2596         }
2597 }
2598
2599 static struct btrfsic_block_link *btrfsic_block_link_lookup_or_add(
2600                 struct btrfsic_state *state,
2601                 struct btrfsic_block_data_ctx *next_block_ctx,
2602                 struct btrfsic_block *next_block,
2603                 struct btrfsic_block *from_block,
2604                 u64 parent_generation)
2605 {
2606         struct btrfsic_block_link *l;
2607
2608         l = btrfsic_block_link_hashtable_lookup(next_block_ctx->dev->bdev,
2609                                                 next_block_ctx->dev_bytenr,
2610                                                 from_block->dev_state->bdev,
2611                                                 from_block->dev_bytenr,
2612                                                 &state->block_link_hashtable);
2613         if (NULL == l) {
2614                 l = btrfsic_block_link_alloc();
2615                 if (NULL == l) {
2616                         pr_info("btrfsic: error, kmalloc failed!\n");
2617                         return NULL;
2618                 }
2619
2620                 l->block_ref_to = next_block;
2621                 l->block_ref_from = from_block;
2622                 l->ref_cnt = 1;
2623                 l->parent_generation = parent_generation;
2624
2625                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2626                         btrfsic_print_add_link(state, l);
2627
2628                 list_add(&l->node_ref_to, &from_block->ref_to_list);
2629                 list_add(&l->node_ref_from, &next_block->ref_from_list);
2630
2631                 btrfsic_block_link_hashtable_add(l,
2632                                                  &state->block_link_hashtable);
2633         } else {
2634                 l->ref_cnt++;
2635                 l->parent_generation = parent_generation;
2636                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2637                         btrfsic_print_add_link(state, l);
2638         }
2639
2640         return l;
2641 }
2642
2643 static struct btrfsic_block *btrfsic_block_lookup_or_add(
2644                 struct btrfsic_state *state,
2645                 struct btrfsic_block_data_ctx *block_ctx,
2646                 const char *additional_string,
2647                 int is_metadata,
2648                 int is_iodone,
2649                 int never_written,
2650                 int mirror_num,
2651                 int *was_created)
2652 {
2653         struct btrfsic_block *block;
2654
2655         block = btrfsic_block_hashtable_lookup(block_ctx->dev->bdev,
2656                                                block_ctx->dev_bytenr,
2657                                                &state->block_hashtable);
2658         if (NULL == block) {
2659                 struct btrfsic_dev_state *dev_state;
2660
2661                 block = btrfsic_block_alloc();
2662                 if (NULL == block) {
2663                         pr_info("btrfsic: error, kmalloc failed!\n");
2664                         return NULL;
2665                 }
2666                 dev_state = btrfsic_dev_state_lookup(block_ctx->dev->bdev);
2667                 if (NULL == dev_state) {
2668                         pr_info("btrfsic: error, lookup dev_state failed!\n");
2669                         btrfsic_block_free(block);
2670                         return NULL;
2671                 }
2672                 block->dev_state = dev_state;
2673                 block->dev_bytenr = block_ctx->dev_bytenr;
2674                 block->logical_bytenr = block_ctx->start;
2675                 block->is_metadata = is_metadata;
2676                 block->is_iodone = is_iodone;
2677                 block->never_written = never_written;
2678                 block->mirror_num = mirror_num;
2679                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2680                         pr_info("New %s%c-block @%llu (%s/%llu/%d)\n",
2681                                additional_string,
2682                                btrfsic_get_block_type(state, block),
2683                                block->logical_bytenr, dev_state->name,
2684                                block->dev_bytenr, mirror_num);
2685                 list_add(&block->all_blocks_node, &state->all_blocks_list);
2686                 btrfsic_block_hashtable_add(block, &state->block_hashtable);
2687                 if (NULL != was_created)
2688                         *was_created = 1;
2689         } else {
2690                 if (NULL != was_created)
2691                         *was_created = 0;
2692         }
2693
2694         return block;
2695 }
2696
2697 static void btrfsic_cmp_log_and_dev_bytenr(struct btrfsic_state *state,
2698                                            u64 bytenr,
2699                                            struct btrfsic_dev_state *dev_state,
2700                                            u64 dev_bytenr)
2701 {
2702         int num_copies;
2703         int mirror_num;
2704         int ret;
2705         struct btrfsic_block_data_ctx block_ctx;
2706         int match = 0;
2707
2708         num_copies = btrfs_num_copies(state->root->fs_info,
2709                                       bytenr, state->metablock_size);
2710
2711         for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
2712                 ret = btrfsic_map_block(state, bytenr, state->metablock_size,
2713                                         &block_ctx, mirror_num);
2714                 if (ret) {
2715                         pr_info("btrfsic: btrfsic_map_block(logical @%llu, mirror %d) failed!\n",
2716                                bytenr, mirror_num);
2717                         continue;
2718                 }
2719
2720                 if (dev_state->bdev == block_ctx.dev->bdev &&
2721                     dev_bytenr == block_ctx.dev_bytenr) {
2722                         match++;
2723                         btrfsic_release_block_ctx(&block_ctx);
2724                         break;
2725                 }
2726                 btrfsic_release_block_ctx(&block_ctx);
2727         }
2728
2729         if (WARN_ON(!match)) {
2730                 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",
2731                        bytenr, dev_state->name, dev_bytenr);
2732                 for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
2733                         ret = btrfsic_map_block(state, bytenr,
2734                                                 state->metablock_size,
2735                                                 &block_ctx, mirror_num);
2736                         if (ret)
2737                                 continue;
2738
2739                         pr_info("Read logical bytenr @%llu maps to (%s/%llu/%d)\n",
2740                                bytenr, block_ctx.dev->name,
2741                                block_ctx.dev_bytenr, mirror_num);
2742                 }
2743         }
2744 }
2745
2746 static struct btrfsic_dev_state *btrfsic_dev_state_lookup(
2747                 struct block_device *bdev)
2748 {
2749         return btrfsic_dev_state_hashtable_lookup(bdev,
2750                                                   &btrfsic_dev_state_hashtable);
2751 }
2752
2753 int btrfsic_submit_bh(int op, int op_flags, struct buffer_head *bh)
2754 {
2755         struct btrfsic_dev_state *dev_state;
2756
2757         if (!btrfsic_is_initialized)
2758                 return submit_bh(op, op_flags, bh);
2759
2760         mutex_lock(&btrfsic_mutex);
2761         /* since btrfsic_submit_bh() might also be called before
2762          * btrfsic_mount(), this might return NULL */
2763         dev_state = btrfsic_dev_state_lookup(bh->b_bdev);
2764
2765         /* Only called to write the superblock (incl. FLUSH/FUA) */
2766         if (NULL != dev_state &&
2767             (op == REQ_OP_WRITE) && bh->b_size > 0) {
2768                 u64 dev_bytenr;
2769
2770                 dev_bytenr = 4096 * bh->b_blocknr;
2771                 if (dev_state->state->print_mask &
2772                     BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
2773                         pr_info("submit_bh(op=0x%x,0x%x, blocknr=%llu (bytenr %llu), size=%zu, data=%p, bdev=%p)\n",
2774                                op, op_flags, (unsigned long long)bh->b_blocknr,
2775                                dev_bytenr, bh->b_size, bh->b_data, bh->b_bdev);
2776                 btrfsic_process_written_block(dev_state, dev_bytenr,
2777                                               &bh->b_data, 1, NULL,
2778                                               NULL, bh, op_flags);
2779         } else if (NULL != dev_state && (op_flags & REQ_PREFLUSH)) {
2780                 if (dev_state->state->print_mask &
2781                     BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
2782                         pr_info("submit_bh(op=0x%x,0x%x FLUSH, bdev=%p)\n",
2783                                op, op_flags, bh->b_bdev);
2784                 if (!dev_state->dummy_block_for_bio_bh_flush.is_iodone) {
2785                         if ((dev_state->state->print_mask &
2786                              (BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH |
2787                               BTRFSIC_PRINT_MASK_VERBOSE)))
2788                                 pr_info("btrfsic_submit_bh(%s) with FLUSH but dummy block already in use (ignored)!\n",
2789                                        dev_state->name);
2790                 } else {
2791                         struct btrfsic_block *const block =
2792                                 &dev_state->dummy_block_for_bio_bh_flush;
2793
2794                         block->is_iodone = 0;
2795                         block->never_written = 0;
2796                         block->iodone_w_error = 0;
2797                         block->flush_gen = dev_state->last_flush_gen + 1;
2798                         block->submit_bio_bh_rw = op_flags;
2799                         block->orig_bio_bh_private = bh->b_private;
2800                         block->orig_bio_bh_end_io.bh = bh->b_end_io;
2801                         block->next_in_same_bio = NULL;
2802                         bh->b_private = block;
2803                         bh->b_end_io = btrfsic_bh_end_io;
2804                 }
2805         }
2806         mutex_unlock(&btrfsic_mutex);
2807         return submit_bh(op, op_flags, bh);
2808 }
2809
2810 static void __btrfsic_submit_bio(struct bio *bio)
2811 {
2812         struct btrfsic_dev_state *dev_state;
2813
2814         if (!btrfsic_is_initialized)
2815                 return;
2816
2817         mutex_lock(&btrfsic_mutex);
2818         /* since btrfsic_submit_bio() is also called before
2819          * btrfsic_mount(), this might return NULL */
2820         dev_state = btrfsic_dev_state_lookup(bio->bi_bdev);
2821         if (NULL != dev_state &&
2822             (bio_op(bio) == REQ_OP_WRITE) && NULL != bio->bi_io_vec) {
2823                 unsigned int i;
2824                 u64 dev_bytenr;
2825                 u64 cur_bytenr;
2826                 int bio_is_patched;
2827                 char **mapped_datav;
2828
2829                 dev_bytenr = 512 * bio->bi_iter.bi_sector;
2830                 bio_is_patched = 0;
2831                 if (dev_state->state->print_mask &
2832                     BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
2833                         pr_info("submit_bio(rw=%d,0x%x, bi_vcnt=%u, bi_sector=%llu (bytenr %llu), bi_bdev=%p)\n",
2834                                bio_op(bio), bio->bi_opf, bio->bi_vcnt,
2835                                (unsigned long long)bio->bi_iter.bi_sector,
2836                                dev_bytenr, bio->bi_bdev);
2837
2838                 mapped_datav = kmalloc_array(bio->bi_vcnt,
2839                                              sizeof(*mapped_datav), GFP_NOFS);
2840                 if (!mapped_datav)
2841                         goto leave;
2842                 cur_bytenr = dev_bytenr;
2843                 for (i = 0; i < bio->bi_vcnt; i++) {
2844                         BUG_ON(bio->bi_io_vec[i].bv_len != PAGE_SIZE);
2845                         mapped_datav[i] = kmap(bio->bi_io_vec[i].bv_page);
2846                         if (!mapped_datav[i]) {
2847                                 while (i > 0) {
2848                                         i--;
2849                                         kunmap(bio->bi_io_vec[i].bv_page);
2850                                 }
2851                                 kfree(mapped_datav);
2852                                 goto leave;
2853                         }
2854                         if (dev_state->state->print_mask &
2855                             BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH_VERBOSE)
2856                                 pr_info("#%u: bytenr=%llu, len=%u, offset=%u\n",
2857                                        i, cur_bytenr, bio->bi_io_vec[i].bv_len,
2858                                        bio->bi_io_vec[i].bv_offset);
2859                         cur_bytenr += bio->bi_io_vec[i].bv_len;
2860                 }
2861                 btrfsic_process_written_block(dev_state, dev_bytenr,
2862                                               mapped_datav, bio->bi_vcnt,
2863                                               bio, &bio_is_patched,
2864                                               NULL, bio->bi_opf);
2865                 while (i > 0) {
2866                         i--;
2867                         kunmap(bio->bi_io_vec[i].bv_page);
2868                 }
2869                 kfree(mapped_datav);
2870         } else if (NULL != dev_state && (bio->bi_opf & REQ_PREFLUSH)) {
2871                 if (dev_state->state->print_mask &
2872                     BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
2873                         pr_info("submit_bio(rw=%d,0x%x FLUSH, bdev=%p)\n",
2874                                bio_op(bio), bio->bi_opf, bio->bi_bdev);
2875                 if (!dev_state->dummy_block_for_bio_bh_flush.is_iodone) {
2876                         if ((dev_state->state->print_mask &
2877                              (BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH |
2878                               BTRFSIC_PRINT_MASK_VERBOSE)))
2879                                 pr_info("btrfsic_submit_bio(%s) with FLUSH but dummy block already in use (ignored)!\n",
2880                                        dev_state->name);
2881                 } else {
2882                         struct btrfsic_block *const block =
2883                                 &dev_state->dummy_block_for_bio_bh_flush;
2884
2885                         block->is_iodone = 0;
2886                         block->never_written = 0;
2887                         block->iodone_w_error = 0;
2888                         block->flush_gen = dev_state->last_flush_gen + 1;
2889                         block->submit_bio_bh_rw = bio->bi_opf;
2890                         block->orig_bio_bh_private = bio->bi_private;
2891                         block->orig_bio_bh_end_io.bio = bio->bi_end_io;
2892                         block->next_in_same_bio = NULL;
2893                         bio->bi_private = block;
2894                         bio->bi_end_io = btrfsic_bio_end_io;
2895                 }
2896         }
2897 leave:
2898         mutex_unlock(&btrfsic_mutex);
2899 }
2900
2901 void btrfsic_submit_bio(struct bio *bio)
2902 {
2903         __btrfsic_submit_bio(bio);
2904         submit_bio(bio);
2905 }
2906
2907 int btrfsic_submit_bio_wait(struct bio *bio)
2908 {
2909         __btrfsic_submit_bio(bio);
2910         return submit_bio_wait(bio);
2911 }
2912
2913 int btrfsic_mount(struct btrfs_root *root,
2914                   struct btrfs_fs_devices *fs_devices,
2915                   int including_extent_data, u32 print_mask)
2916 {
2917         int ret;
2918         struct btrfsic_state *state;
2919         struct list_head *dev_head = &fs_devices->devices;
2920         struct btrfs_device *device;
2921
2922         if (root->nodesize & ((u64)PAGE_SIZE - 1)) {
2923                 pr_info("btrfsic: cannot handle nodesize %d not being a multiple of PAGE_SIZE %ld!\n",
2924                        root->nodesize, PAGE_SIZE);
2925                 return -1;
2926         }
2927         if (root->sectorsize & ((u64)PAGE_SIZE - 1)) {
2928                 pr_info("btrfsic: cannot handle sectorsize %d not being a multiple of PAGE_SIZE %ld!\n",
2929                        root->sectorsize, PAGE_SIZE);
2930                 return -1;
2931         }
2932         state = kzalloc(sizeof(*state), GFP_KERNEL | __GFP_NOWARN | __GFP_REPEAT);
2933         if (!state) {
2934                 state = vzalloc(sizeof(*state));
2935                 if (!state) {
2936                         pr_info("btrfs check-integrity: vzalloc() failed!\n");
2937                         return -1;
2938                 }
2939         }
2940
2941         if (!btrfsic_is_initialized) {
2942                 mutex_init(&btrfsic_mutex);
2943                 btrfsic_dev_state_hashtable_init(&btrfsic_dev_state_hashtable);
2944                 btrfsic_is_initialized = 1;
2945         }
2946         mutex_lock(&btrfsic_mutex);
2947         state->root = root;
2948         state->print_mask = print_mask;
2949         state->include_extent_data = including_extent_data;
2950         state->csum_size = 0;
2951         state->metablock_size = root->nodesize;
2952         state->datablock_size = root->sectorsize;
2953         INIT_LIST_HEAD(&state->all_blocks_list);
2954         btrfsic_block_hashtable_init(&state->block_hashtable);
2955         btrfsic_block_link_hashtable_init(&state->block_link_hashtable);
2956         state->max_superblock_generation = 0;
2957         state->latest_superblock = NULL;
2958
2959         list_for_each_entry(device, dev_head, dev_list) {
2960                 struct btrfsic_dev_state *ds;
2961                 const char *p;
2962
2963                 if (!device->bdev || !device->name)
2964                         continue;
2965
2966                 ds = btrfsic_dev_state_alloc();
2967                 if (NULL == ds) {
2968                         pr_info("btrfs check-integrity: kmalloc() failed!\n");
2969                         mutex_unlock(&btrfsic_mutex);
2970                         return -1;
2971                 }
2972                 ds->bdev = device->bdev;
2973                 ds->state = state;
2974                 bdevname(ds->bdev, ds->name);
2975                 ds->name[BDEVNAME_SIZE - 1] = '\0';
2976                 p = kbasename(ds->name);
2977                 strlcpy(ds->name, p, sizeof(ds->name));
2978                 btrfsic_dev_state_hashtable_add(ds,
2979                                                 &btrfsic_dev_state_hashtable);
2980         }
2981
2982         ret = btrfsic_process_superblock(state, fs_devices);
2983         if (0 != ret) {
2984                 mutex_unlock(&btrfsic_mutex);
2985                 btrfsic_unmount(root, fs_devices);
2986                 return ret;
2987         }
2988
2989         if (state->print_mask & BTRFSIC_PRINT_MASK_INITIAL_DATABASE)
2990                 btrfsic_dump_database(state);
2991         if (state->print_mask & BTRFSIC_PRINT_MASK_INITIAL_TREE)
2992                 btrfsic_dump_tree(state);
2993
2994         mutex_unlock(&btrfsic_mutex);
2995         return 0;
2996 }
2997
2998 void btrfsic_unmount(struct btrfs_root *root,
2999                      struct btrfs_fs_devices *fs_devices)
3000 {
3001         struct btrfsic_block *b_all, *tmp_all;
3002         struct btrfsic_state *state;
3003         struct list_head *dev_head = &fs_devices->devices;
3004         struct btrfs_device *device;
3005
3006         if (!btrfsic_is_initialized)
3007                 return;
3008
3009         mutex_lock(&btrfsic_mutex);
3010
3011         state = NULL;
3012         list_for_each_entry(device, dev_head, dev_list) {
3013                 struct btrfsic_dev_state *ds;
3014
3015                 if (!device->bdev || !device->name)
3016                         continue;
3017
3018                 ds = btrfsic_dev_state_hashtable_lookup(
3019                                 device->bdev,
3020                                 &btrfsic_dev_state_hashtable);
3021                 if (NULL != ds) {
3022                         state = ds->state;
3023                         btrfsic_dev_state_hashtable_remove(ds);
3024                         btrfsic_dev_state_free(ds);
3025                 }
3026         }
3027
3028         if (NULL == state) {
3029                 pr_info("btrfsic: error, cannot find state information on umount!\n");
3030                 mutex_unlock(&btrfsic_mutex);
3031                 return;
3032         }
3033
3034         /*
3035          * Don't care about keeping the lists' state up to date,
3036          * just free all memory that was allocated dynamically.
3037          * Free the blocks and the block_links.
3038          */
3039         list_for_each_entry_safe(b_all, tmp_all, &state->all_blocks_list,
3040                                  all_blocks_node) {
3041                 struct btrfsic_block_link *l, *tmp;
3042
3043                 list_for_each_entry_safe(l, tmp, &b_all->ref_to_list,
3044                                          node_ref_to) {
3045                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
3046                                 btrfsic_print_rem_link(state, l);
3047
3048                         l->ref_cnt--;
3049                         if (0 == l->ref_cnt)
3050                                 btrfsic_block_link_free(l);
3051                 }
3052
3053                 if (b_all->is_iodone || b_all->never_written)
3054                         btrfsic_block_free(b_all);
3055                 else
3056                         pr_info("btrfs: attempt to free %c-block @%llu (%s/%llu/%d) on umount which is not yet iodone!\n",
3057                                btrfsic_get_block_type(state, b_all),
3058                                b_all->logical_bytenr, b_all->dev_state->name,
3059                                b_all->dev_bytenr, b_all->mirror_num);
3060         }
3061
3062         mutex_unlock(&btrfsic_mutex);
3063
3064         kvfree(state);
3065 }