check-integrity.c revision 5d9640517d92d05843711ea982cbeff42d7ed32d
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
82#include <linux/sched.h>
83#include <linux/slab.h>
84#include <linux/buffer_head.h>
85#include <linux/mutex.h>
86#include <linux/crc32c.h>
87#include <linux/genhd.h>
88#include <linux/blkdev.h>
89#include "ctree.h"
90#include "disk-io.h"
91#include "transaction.h"
92#include "extent_io.h"
93#include "volumes.h"
94#include "print-tree.h"
95#include "locking.h"
96#include "check-integrity.h"
97#include "rcu-string.h"
98
99#define BTRFSIC_BLOCK_HASHTABLE_SIZE 0x10000
100#define BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE 0x10000
101#define BTRFSIC_DEV2STATE_HASHTABLE_SIZE 0x100
102#define BTRFSIC_BLOCK_MAGIC_NUMBER 0x14491051
103#define BTRFSIC_BLOCK_LINK_MAGIC_NUMBER 0x11070807
104#define BTRFSIC_DEV2STATE_MAGIC_NUMBER 0x20111530
105#define BTRFSIC_BLOCK_STACK_FRAME_MAGIC_NUMBER 20111300
106#define BTRFSIC_TREE_DUMP_MAX_INDENT_LEVEL (200 - 6)	/* in characters,
107							 * excluding " [...]" */
108#define BTRFSIC_GENERATION_UNKNOWN ((u64)-1)
109
110/*
111 * The definition of the bitmask fields for the print_mask.
112 * They are specified with the mount option check_integrity_print_mask.
113 */
114#define BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE			0x00000001
115#define BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION		0x00000002
116#define BTRFSIC_PRINT_MASK_TREE_AFTER_SB_WRITE			0x00000004
117#define BTRFSIC_PRINT_MASK_TREE_BEFORE_SB_WRITE			0x00000008
118#define BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH			0x00000010
119#define BTRFSIC_PRINT_MASK_END_IO_BIO_BH			0x00000020
120#define BTRFSIC_PRINT_MASK_VERBOSE				0x00000040
121#define BTRFSIC_PRINT_MASK_VERY_VERBOSE				0x00000080
122#define BTRFSIC_PRINT_MASK_INITIAL_TREE				0x00000100
123#define BTRFSIC_PRINT_MASK_INITIAL_ALL_TREES			0x00000200
124#define BTRFSIC_PRINT_MASK_INITIAL_DATABASE			0x00000400
125#define BTRFSIC_PRINT_MASK_NUM_COPIES				0x00000800
126#define BTRFSIC_PRINT_MASK_TREE_WITH_ALL_MIRRORS		0x00001000
127
128struct btrfsic_dev_state;
129struct btrfsic_state;
130
131struct btrfsic_block {
132	u32 magic_num;		/* only used for debug purposes */
133	unsigned int is_metadata:1;	/* if it is meta-data, not data-data */
134	unsigned int is_superblock:1;	/* if it is one of the superblocks */
135	unsigned int is_iodone:1;	/* if is done by lower subsystem */
136	unsigned int iodone_w_error:1;	/* error was indicated to endio */
137	unsigned int never_written:1;	/* block was added because it was
138					 * referenced, not because it was
139					 * written */
140	unsigned int mirror_num:2;	/* large enough to hold
141					 * BTRFS_SUPER_MIRROR_MAX */
142	struct btrfsic_dev_state *dev_state;
143	u64 dev_bytenr;		/* key, physical byte num on disk */
144	u64 logical_bytenr;	/* logical byte num on disk */
145	u64 generation;
146	struct btrfs_disk_key disk_key;	/* extra info to print in case of
147					 * issues, will not always be correct */
148	struct list_head collision_resolving_node;	/* list node */
149	struct list_head all_blocks_node;	/* list node */
150
151	/* the following two lists contain block_link items */
152	struct list_head ref_to_list;	/* list */
153	struct list_head ref_from_list;	/* list */
154	struct btrfsic_block *next_in_same_bio;
155	void *orig_bio_bh_private;
156	union {
157		bio_end_io_t *bio;
158		bh_end_io_t *bh;
159	} orig_bio_bh_end_io;
160	int submit_bio_bh_rw;
161	u64 flush_gen; /* only valid if !never_written */
162};
163
164/*
165 * Elements of this type are allocated dynamically and required because
166 * each block object can refer to and can be ref from multiple blocks.
167 * The key to lookup them in the hashtable is the dev_bytenr of
168 * the block ref to plus the one from the block refered from.
169 * The fact that they are searchable via a hashtable and that a
170 * ref_cnt is maintained is not required for the btrfs integrity
171 * check algorithm itself, it is only used to make the output more
172 * beautiful in case that an error is detected (an error is defined
173 * as a write operation to a block while that block is still referenced).
174 */
175struct btrfsic_block_link {
176	u32 magic_num;		/* only used for debug purposes */
177	u32 ref_cnt;
178	struct list_head node_ref_to;	/* list node */
179	struct list_head node_ref_from;	/* list node */
180	struct list_head collision_resolving_node;	/* list node */
181	struct btrfsic_block *block_ref_to;
182	struct btrfsic_block *block_ref_from;
183	u64 parent_generation;
184};
185
186struct btrfsic_dev_state {
187	u32 magic_num;		/* only used for debug purposes */
188	struct block_device *bdev;
189	struct btrfsic_state *state;
190	struct list_head collision_resolving_node;	/* list node */
191	struct btrfsic_block dummy_block_for_bio_bh_flush;
192	u64 last_flush_gen;
193	char name[BDEVNAME_SIZE];
194};
195
196struct btrfsic_block_hashtable {
197	struct list_head table[BTRFSIC_BLOCK_HASHTABLE_SIZE];
198};
199
200struct btrfsic_block_link_hashtable {
201	struct list_head table[BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE];
202};
203
204struct btrfsic_dev_state_hashtable {
205	struct list_head table[BTRFSIC_DEV2STATE_HASHTABLE_SIZE];
206};
207
208struct btrfsic_block_data_ctx {
209	u64 start;		/* virtual bytenr */
210	u64 dev_bytenr;		/* physical bytenr on device */
211	u32 len;
212	struct btrfsic_dev_state *dev;
213	char **datav;
214	struct page **pagev;
215	void *mem_to_free;
216};
217
218/* This structure is used to implement recursion without occupying
219 * any stack space, refer to btrfsic_process_metablock() */
220struct btrfsic_stack_frame {
221	u32 magic;
222	u32 nr;
223	int error;
224	int i;
225	int limit_nesting;
226	int num_copies;
227	int mirror_num;
228	struct btrfsic_block *block;
229	struct btrfsic_block_data_ctx *block_ctx;
230	struct btrfsic_block *next_block;
231	struct btrfsic_block_data_ctx next_block_ctx;
232	struct btrfs_header *hdr;
233	struct btrfsic_stack_frame *prev;
234};
235
236/* Some state per mounted filesystem */
237struct btrfsic_state {
238	u32 print_mask;
239	int include_extent_data;
240	int csum_size;
241	struct list_head all_blocks_list;
242	struct btrfsic_block_hashtable block_hashtable;
243	struct btrfsic_block_link_hashtable block_link_hashtable;
244	struct btrfs_root *root;
245	u64 max_superblock_generation;
246	struct btrfsic_block *latest_superblock;
247	u32 metablock_size;
248	u32 datablock_size;
249};
250
251static void btrfsic_block_init(struct btrfsic_block *b);
252static struct btrfsic_block *btrfsic_block_alloc(void);
253static void btrfsic_block_free(struct btrfsic_block *b);
254static void btrfsic_block_link_init(struct btrfsic_block_link *n);
255static struct btrfsic_block_link *btrfsic_block_link_alloc(void);
256static void btrfsic_block_link_free(struct btrfsic_block_link *n);
257static void btrfsic_dev_state_init(struct btrfsic_dev_state *ds);
258static struct btrfsic_dev_state *btrfsic_dev_state_alloc(void);
259static void btrfsic_dev_state_free(struct btrfsic_dev_state *ds);
260static void btrfsic_block_hashtable_init(struct btrfsic_block_hashtable *h);
261static void btrfsic_block_hashtable_add(struct btrfsic_block *b,
262					struct btrfsic_block_hashtable *h);
263static void btrfsic_block_hashtable_remove(struct btrfsic_block *b);
264static struct btrfsic_block *btrfsic_block_hashtable_lookup(
265		struct block_device *bdev,
266		u64 dev_bytenr,
267		struct btrfsic_block_hashtable *h);
268static void btrfsic_block_link_hashtable_init(
269		struct btrfsic_block_link_hashtable *h);
270static void btrfsic_block_link_hashtable_add(
271		struct btrfsic_block_link *l,
272		struct btrfsic_block_link_hashtable *h);
273static void btrfsic_block_link_hashtable_remove(struct btrfsic_block_link *l);
274static struct btrfsic_block_link *btrfsic_block_link_hashtable_lookup(
275		struct block_device *bdev_ref_to,
276		u64 dev_bytenr_ref_to,
277		struct block_device *bdev_ref_from,
278		u64 dev_bytenr_ref_from,
279		struct btrfsic_block_link_hashtable *h);
280static void btrfsic_dev_state_hashtable_init(
281		struct btrfsic_dev_state_hashtable *h);
282static void btrfsic_dev_state_hashtable_add(
283		struct btrfsic_dev_state *ds,
284		struct btrfsic_dev_state_hashtable *h);
285static void btrfsic_dev_state_hashtable_remove(struct btrfsic_dev_state *ds);
286static struct btrfsic_dev_state *btrfsic_dev_state_hashtable_lookup(
287		struct block_device *bdev,
288		struct btrfsic_dev_state_hashtable *h);
289static struct btrfsic_stack_frame *btrfsic_stack_frame_alloc(void);
290static void btrfsic_stack_frame_free(struct btrfsic_stack_frame *sf);
291static int btrfsic_process_superblock(struct btrfsic_state *state,
292				      struct btrfs_fs_devices *fs_devices);
293static int btrfsic_process_metablock(struct btrfsic_state *state,
294				     struct btrfsic_block *block,
295				     struct btrfsic_block_data_ctx *block_ctx,
296				     int limit_nesting, int force_iodone_flag);
297static void btrfsic_read_from_block_data(
298	struct btrfsic_block_data_ctx *block_ctx,
299	void *dst, u32 offset, size_t len);
300static int btrfsic_create_link_to_next_block(
301		struct btrfsic_state *state,
302		struct btrfsic_block *block,
303		struct btrfsic_block_data_ctx
304		*block_ctx, u64 next_bytenr,
305		int limit_nesting,
306		struct btrfsic_block_data_ctx *next_block_ctx,
307		struct btrfsic_block **next_blockp,
308		int force_iodone_flag,
309		int *num_copiesp, int *mirror_nump,
310		struct btrfs_disk_key *disk_key,
311		u64 parent_generation);
312static int btrfsic_handle_extent_data(struct btrfsic_state *state,
313				      struct btrfsic_block *block,
314				      struct btrfsic_block_data_ctx *block_ctx,
315				      u32 item_offset, int force_iodone_flag);
316static int btrfsic_map_block(struct btrfsic_state *state, u64 bytenr, u32 len,
317			     struct btrfsic_block_data_ctx *block_ctx_out,
318			     int mirror_num);
319static int btrfsic_map_superblock(struct btrfsic_state *state, u64 bytenr,
320				  u32 len, struct block_device *bdev,
321				  struct btrfsic_block_data_ctx *block_ctx_out);
322static void btrfsic_release_block_ctx(struct btrfsic_block_data_ctx *block_ctx);
323static int btrfsic_read_block(struct btrfsic_state *state,
324			      struct btrfsic_block_data_ctx *block_ctx);
325static void btrfsic_dump_database(struct btrfsic_state *state);
326static void btrfsic_complete_bio_end_io(struct bio *bio, int err);
327static int btrfsic_test_for_metadata(struct btrfsic_state *state,
328				     char **datav, unsigned int num_pages);
329static void btrfsic_process_written_block(struct btrfsic_dev_state *dev_state,
330					  u64 dev_bytenr, char **mapped_datav,
331					  unsigned int num_pages,
332					  struct bio *bio, int *bio_is_patched,
333					  struct buffer_head *bh,
334					  int submit_bio_bh_rw);
335static int btrfsic_process_written_superblock(
336		struct btrfsic_state *state,
337		struct btrfsic_block *const block,
338		struct btrfs_super_block *const super_hdr);
339static void btrfsic_bio_end_io(struct bio *bp, int bio_error_status);
340static void btrfsic_bh_end_io(struct buffer_head *bh, int uptodate);
341static int btrfsic_is_block_ref_by_superblock(const struct btrfsic_state *state,
342					      const struct btrfsic_block *block,
343					      int recursion_level);
344static int btrfsic_check_all_ref_blocks(struct btrfsic_state *state,
345					struct btrfsic_block *const block,
346					int recursion_level);
347static void btrfsic_print_add_link(const struct btrfsic_state *state,
348				   const struct btrfsic_block_link *l);
349static void btrfsic_print_rem_link(const struct btrfsic_state *state,
350				   const struct btrfsic_block_link *l);
351static char btrfsic_get_block_type(const struct btrfsic_state *state,
352				   const struct btrfsic_block *block);
353static void btrfsic_dump_tree(const struct btrfsic_state *state);
354static void btrfsic_dump_tree_sub(const struct btrfsic_state *state,
355				  const struct btrfsic_block *block,
356				  int indent_level);
357static struct btrfsic_block_link *btrfsic_block_link_lookup_or_add(
358		struct btrfsic_state *state,
359		struct btrfsic_block_data_ctx *next_block_ctx,
360		struct btrfsic_block *next_block,
361		struct btrfsic_block *from_block,
362		u64 parent_generation);
363static struct btrfsic_block *btrfsic_block_lookup_or_add(
364		struct btrfsic_state *state,
365		struct btrfsic_block_data_ctx *block_ctx,
366		const char *additional_string,
367		int is_metadata,
368		int is_iodone,
369		int never_written,
370		int mirror_num,
371		int *was_created);
372static int btrfsic_process_superblock_dev_mirror(
373		struct btrfsic_state *state,
374		struct btrfsic_dev_state *dev_state,
375		struct btrfs_device *device,
376		int superblock_mirror_num,
377		struct btrfsic_dev_state **selected_dev_state,
378		struct btrfs_super_block *selected_super);
379static struct btrfsic_dev_state *btrfsic_dev_state_lookup(
380		struct block_device *bdev);
381static void btrfsic_cmp_log_and_dev_bytenr(struct btrfsic_state *state,
382					   u64 bytenr,
383					   struct btrfsic_dev_state *dev_state,
384					   u64 dev_bytenr);
385
386static struct mutex btrfsic_mutex;
387static int btrfsic_is_initialized;
388static struct btrfsic_dev_state_hashtable btrfsic_dev_state_hashtable;
389
390
391static void btrfsic_block_init(struct btrfsic_block *b)
392{
393	b->magic_num = BTRFSIC_BLOCK_MAGIC_NUMBER;
394	b->dev_state = NULL;
395	b->dev_bytenr = 0;
396	b->logical_bytenr = 0;
397	b->generation = BTRFSIC_GENERATION_UNKNOWN;
398	b->disk_key.objectid = 0;
399	b->disk_key.type = 0;
400	b->disk_key.offset = 0;
401	b->is_metadata = 0;
402	b->is_superblock = 0;
403	b->is_iodone = 0;
404	b->iodone_w_error = 0;
405	b->never_written = 0;
406	b->mirror_num = 0;
407	b->next_in_same_bio = NULL;
408	b->orig_bio_bh_private = NULL;
409	b->orig_bio_bh_end_io.bio = NULL;
410	INIT_LIST_HEAD(&b->collision_resolving_node);
411	INIT_LIST_HEAD(&b->all_blocks_node);
412	INIT_LIST_HEAD(&b->ref_to_list);
413	INIT_LIST_HEAD(&b->ref_from_list);
414	b->submit_bio_bh_rw = 0;
415	b->flush_gen = 0;
416}
417
418static struct btrfsic_block *btrfsic_block_alloc(void)
419{
420	struct btrfsic_block *b;
421
422	b = kzalloc(sizeof(*b), GFP_NOFS);
423	if (NULL != b)
424		btrfsic_block_init(b);
425
426	return b;
427}
428
429static void btrfsic_block_free(struct btrfsic_block *b)
430{
431	BUG_ON(!(NULL == b || BTRFSIC_BLOCK_MAGIC_NUMBER == b->magic_num));
432	kfree(b);
433}
434
435static void btrfsic_block_link_init(struct btrfsic_block_link *l)
436{
437	l->magic_num = BTRFSIC_BLOCK_LINK_MAGIC_NUMBER;
438	l->ref_cnt = 1;
439	INIT_LIST_HEAD(&l->node_ref_to);
440	INIT_LIST_HEAD(&l->node_ref_from);
441	INIT_LIST_HEAD(&l->collision_resolving_node);
442	l->block_ref_to = NULL;
443	l->block_ref_from = NULL;
444}
445
446static struct btrfsic_block_link *btrfsic_block_link_alloc(void)
447{
448	struct btrfsic_block_link *l;
449
450	l = kzalloc(sizeof(*l), GFP_NOFS);
451	if (NULL != l)
452		btrfsic_block_link_init(l);
453
454	return l;
455}
456
457static void btrfsic_block_link_free(struct btrfsic_block_link *l)
458{
459	BUG_ON(!(NULL == l || BTRFSIC_BLOCK_LINK_MAGIC_NUMBER == l->magic_num));
460	kfree(l);
461}
462
463static void btrfsic_dev_state_init(struct btrfsic_dev_state *ds)
464{
465	ds->magic_num = BTRFSIC_DEV2STATE_MAGIC_NUMBER;
466	ds->bdev = NULL;
467	ds->state = NULL;
468	ds->name[0] = '\0';
469	INIT_LIST_HEAD(&ds->collision_resolving_node);
470	ds->last_flush_gen = 0;
471	btrfsic_block_init(&ds->dummy_block_for_bio_bh_flush);
472	ds->dummy_block_for_bio_bh_flush.is_iodone = 1;
473	ds->dummy_block_for_bio_bh_flush.dev_state = ds;
474}
475
476static struct btrfsic_dev_state *btrfsic_dev_state_alloc(void)
477{
478	struct btrfsic_dev_state *ds;
479
480	ds = kzalloc(sizeof(*ds), GFP_NOFS);
481	if (NULL != ds)
482		btrfsic_dev_state_init(ds);
483
484	return ds;
485}
486
487static void btrfsic_dev_state_free(struct btrfsic_dev_state *ds)
488{
489	BUG_ON(!(NULL == ds ||
490		 BTRFSIC_DEV2STATE_MAGIC_NUMBER == ds->magic_num));
491	kfree(ds);
492}
493
494static void btrfsic_block_hashtable_init(struct btrfsic_block_hashtable *h)
495{
496	int i;
497
498	for (i = 0; i < BTRFSIC_BLOCK_HASHTABLE_SIZE; i++)
499		INIT_LIST_HEAD(h->table + i);
500}
501
502static void btrfsic_block_hashtable_add(struct btrfsic_block *b,
503					struct btrfsic_block_hashtable *h)
504{
505	const unsigned int hashval =
506	    (((unsigned int)(b->dev_bytenr >> 16)) ^
507	     ((unsigned int)((uintptr_t)b->dev_state->bdev))) &
508	     (BTRFSIC_BLOCK_HASHTABLE_SIZE - 1);
509
510	list_add(&b->collision_resolving_node, h->table + hashval);
511}
512
513static void btrfsic_block_hashtable_remove(struct btrfsic_block *b)
514{
515	list_del(&b->collision_resolving_node);
516}
517
518static struct btrfsic_block *btrfsic_block_hashtable_lookup(
519		struct block_device *bdev,
520		u64 dev_bytenr,
521		struct btrfsic_block_hashtable *h)
522{
523	const unsigned int hashval =
524	    (((unsigned int)(dev_bytenr >> 16)) ^
525	     ((unsigned int)((uintptr_t)bdev))) &
526	     (BTRFSIC_BLOCK_HASHTABLE_SIZE - 1);
527	struct list_head *elem;
528
529	list_for_each(elem, h->table + hashval) {
530		struct btrfsic_block *const b =
531		    list_entry(elem, struct btrfsic_block,
532			       collision_resolving_node);
533
534		if (b->dev_state->bdev == bdev && b->dev_bytenr == dev_bytenr)
535			return b;
536	}
537
538	return NULL;
539}
540
541static void btrfsic_block_link_hashtable_init(
542		struct btrfsic_block_link_hashtable *h)
543{
544	int i;
545
546	for (i = 0; i < BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE; i++)
547		INIT_LIST_HEAD(h->table + i);
548}
549
550static void btrfsic_block_link_hashtable_add(
551		struct btrfsic_block_link *l,
552		struct btrfsic_block_link_hashtable *h)
553{
554	const unsigned int hashval =
555	    (((unsigned int)(l->block_ref_to->dev_bytenr >> 16)) ^
556	     ((unsigned int)(l->block_ref_from->dev_bytenr >> 16)) ^
557	     ((unsigned int)((uintptr_t)l->block_ref_to->dev_state->bdev)) ^
558	     ((unsigned int)((uintptr_t)l->block_ref_from->dev_state->bdev)))
559	     & (BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE - 1);
560
561	BUG_ON(NULL == l->block_ref_to);
562	BUG_ON(NULL == l->block_ref_from);
563	list_add(&l->collision_resolving_node, h->table + hashval);
564}
565
566static void btrfsic_block_link_hashtable_remove(struct btrfsic_block_link *l)
567{
568	list_del(&l->collision_resolving_node);
569}
570
571static struct btrfsic_block_link *btrfsic_block_link_hashtable_lookup(
572		struct block_device *bdev_ref_to,
573		u64 dev_bytenr_ref_to,
574		struct block_device *bdev_ref_from,
575		u64 dev_bytenr_ref_from,
576		struct btrfsic_block_link_hashtable *h)
577{
578	const unsigned int hashval =
579	    (((unsigned int)(dev_bytenr_ref_to >> 16)) ^
580	     ((unsigned int)(dev_bytenr_ref_from >> 16)) ^
581	     ((unsigned int)((uintptr_t)bdev_ref_to)) ^
582	     ((unsigned int)((uintptr_t)bdev_ref_from))) &
583	     (BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE - 1);
584	struct list_head *elem;
585
586	list_for_each(elem, h->table + hashval) {
587		struct btrfsic_block_link *const l =
588		    list_entry(elem, struct btrfsic_block_link,
589			       collision_resolving_node);
590
591		BUG_ON(NULL == l->block_ref_to);
592		BUG_ON(NULL == l->block_ref_from);
593		if (l->block_ref_to->dev_state->bdev == bdev_ref_to &&
594		    l->block_ref_to->dev_bytenr == dev_bytenr_ref_to &&
595		    l->block_ref_from->dev_state->bdev == bdev_ref_from &&
596		    l->block_ref_from->dev_bytenr == dev_bytenr_ref_from)
597			return l;
598	}
599
600	return NULL;
601}
602
603static void btrfsic_dev_state_hashtable_init(
604		struct btrfsic_dev_state_hashtable *h)
605{
606	int i;
607
608	for (i = 0; i < BTRFSIC_DEV2STATE_HASHTABLE_SIZE; i++)
609		INIT_LIST_HEAD(h->table + i);
610}
611
612static void btrfsic_dev_state_hashtable_add(
613		struct btrfsic_dev_state *ds,
614		struct btrfsic_dev_state_hashtable *h)
615{
616	const unsigned int hashval =
617	    (((unsigned int)((uintptr_t)ds->bdev)) &
618	     (BTRFSIC_DEV2STATE_HASHTABLE_SIZE - 1));
619
620	list_add(&ds->collision_resolving_node, h->table + hashval);
621}
622
623static void btrfsic_dev_state_hashtable_remove(struct btrfsic_dev_state *ds)
624{
625	list_del(&ds->collision_resolving_node);
626}
627
628static struct btrfsic_dev_state *btrfsic_dev_state_hashtable_lookup(
629		struct block_device *bdev,
630		struct btrfsic_dev_state_hashtable *h)
631{
632	const unsigned int hashval =
633	    (((unsigned int)((uintptr_t)bdev)) &
634	     (BTRFSIC_DEV2STATE_HASHTABLE_SIZE - 1));
635	struct list_head *elem;
636
637	list_for_each(elem, h->table + hashval) {
638		struct btrfsic_dev_state *const ds =
639		    list_entry(elem, struct btrfsic_dev_state,
640			       collision_resolving_node);
641
642		if (ds->bdev == bdev)
643			return ds;
644	}
645
646	return NULL;
647}
648
649static int btrfsic_process_superblock(struct btrfsic_state *state,
650				      struct btrfs_fs_devices *fs_devices)
651{
652	int ret = 0;
653	struct btrfs_super_block *selected_super;
654	struct list_head *dev_head = &fs_devices->devices;
655	struct btrfs_device *device;
656	struct btrfsic_dev_state *selected_dev_state = NULL;
657	int pass;
658
659	BUG_ON(NULL == state);
660	selected_super = kzalloc(sizeof(*selected_super), GFP_NOFS);
661	if (NULL == selected_super) {
662		printk(KERN_INFO "btrfsic: error, kmalloc failed!\n");
663		return -1;
664	}
665
666	list_for_each_entry(device, dev_head, dev_list) {
667		int i;
668		struct btrfsic_dev_state *dev_state;
669
670		if (!device->bdev || !device->name)
671			continue;
672
673		dev_state = btrfsic_dev_state_lookup(device->bdev);
674		BUG_ON(NULL == dev_state);
675		for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
676			ret = btrfsic_process_superblock_dev_mirror(
677					state, dev_state, device, i,
678					&selected_dev_state, selected_super);
679			if (0 != ret && 0 == i) {
680				kfree(selected_super);
681				return ret;
682			}
683		}
684	}
685
686	if (NULL == state->latest_superblock) {
687		printk(KERN_INFO "btrfsic: no superblock found!\n");
688		kfree(selected_super);
689		return -1;
690	}
691
692	state->csum_size = btrfs_super_csum_size(selected_super);
693
694	for (pass = 0; pass < 3; pass++) {
695		int num_copies;
696		int mirror_num;
697		u64 next_bytenr;
698
699		switch (pass) {
700		case 0:
701			next_bytenr = btrfs_super_root(selected_super);
702			if (state->print_mask &
703			    BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
704				printk(KERN_INFO "root@%llu\n",
705				       (unsigned long long)next_bytenr);
706			break;
707		case 1:
708			next_bytenr = btrfs_super_chunk_root(selected_super);
709			if (state->print_mask &
710			    BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
711				printk(KERN_INFO "chunk@%llu\n",
712				       (unsigned long long)next_bytenr);
713			break;
714		case 2:
715			next_bytenr = btrfs_super_log_root(selected_super);
716			if (0 == next_bytenr)
717				continue;
718			if (state->print_mask &
719			    BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
720				printk(KERN_INFO "log@%llu\n",
721				       (unsigned long long)next_bytenr);
722			break;
723		}
724
725		num_copies =
726		    btrfs_num_copies(state->root->fs_info,
727				     next_bytenr, state->metablock_size);
728		if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
729			printk(KERN_INFO "num_copies(log_bytenr=%llu) = %d\n",
730			       (unsigned long long)next_bytenr, num_copies);
731
732		for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
733			struct btrfsic_block *next_block;
734			struct btrfsic_block_data_ctx tmp_next_block_ctx;
735			struct btrfsic_block_link *l;
736
737			ret = btrfsic_map_block(state, next_bytenr,
738						state->metablock_size,
739						&tmp_next_block_ctx,
740						mirror_num);
741			if (ret) {
742				printk(KERN_INFO "btrfsic:"
743				       " btrfsic_map_block(root @%llu,"
744				       " mirror %d) failed!\n",
745				       (unsigned long long)next_bytenr,
746				       mirror_num);
747				kfree(selected_super);
748				return -1;
749			}
750
751			next_block = btrfsic_block_hashtable_lookup(
752					tmp_next_block_ctx.dev->bdev,
753					tmp_next_block_ctx.dev_bytenr,
754					&state->block_hashtable);
755			BUG_ON(NULL == next_block);
756
757			l = btrfsic_block_link_hashtable_lookup(
758					tmp_next_block_ctx.dev->bdev,
759					tmp_next_block_ctx.dev_bytenr,
760					state->latest_superblock->dev_state->
761					bdev,
762					state->latest_superblock->dev_bytenr,
763					&state->block_link_hashtable);
764			BUG_ON(NULL == l);
765
766			ret = btrfsic_read_block(state, &tmp_next_block_ctx);
767			if (ret < (int)PAGE_CACHE_SIZE) {
768				printk(KERN_INFO
769				       "btrfsic: read @logical %llu failed!\n",
770				       (unsigned long long)
771				       tmp_next_block_ctx.start);
772				btrfsic_release_block_ctx(&tmp_next_block_ctx);
773				kfree(selected_super);
774				return -1;
775			}
776
777			ret = btrfsic_process_metablock(state,
778							next_block,
779							&tmp_next_block_ctx,
780							BTRFS_MAX_LEVEL + 3, 1);
781			btrfsic_release_block_ctx(&tmp_next_block_ctx);
782		}
783	}
784
785	kfree(selected_super);
786	return ret;
787}
788
789static int btrfsic_process_superblock_dev_mirror(
790		struct btrfsic_state *state,
791		struct btrfsic_dev_state *dev_state,
792		struct btrfs_device *device,
793		int superblock_mirror_num,
794		struct btrfsic_dev_state **selected_dev_state,
795		struct btrfs_super_block *selected_super)
796{
797	struct btrfs_super_block *super_tmp;
798	u64 dev_bytenr;
799	struct buffer_head *bh;
800	struct btrfsic_block *superblock_tmp;
801	int pass;
802	struct block_device *const superblock_bdev = device->bdev;
803
804	/* super block bytenr is always the unmapped device bytenr */
805	dev_bytenr = btrfs_sb_offset(superblock_mirror_num);
806	if (dev_bytenr + BTRFS_SUPER_INFO_SIZE > device->total_bytes)
807		return -1;
808	bh = __bread(superblock_bdev, dev_bytenr / 4096,
809		     BTRFS_SUPER_INFO_SIZE);
810	if (NULL == bh)
811		return -1;
812	super_tmp = (struct btrfs_super_block *)
813	    (bh->b_data + (dev_bytenr & 4095));
814
815	if (btrfs_super_bytenr(super_tmp) != dev_bytenr ||
816	    strncmp((char *)(&(super_tmp->magic)), BTRFS_MAGIC,
817		    sizeof(super_tmp->magic)) ||
818	    memcmp(device->uuid, super_tmp->dev_item.uuid, BTRFS_UUID_SIZE) ||
819	    btrfs_super_nodesize(super_tmp) != state->metablock_size ||
820	    btrfs_super_leafsize(super_tmp) != state->metablock_size ||
821	    btrfs_super_sectorsize(super_tmp) != state->datablock_size) {
822		brelse(bh);
823		return 0;
824	}
825
826	superblock_tmp =
827	    btrfsic_block_hashtable_lookup(superblock_bdev,
828					   dev_bytenr,
829					   &state->block_hashtable);
830	if (NULL == superblock_tmp) {
831		superblock_tmp = btrfsic_block_alloc();
832		if (NULL == superblock_tmp) {
833			printk(KERN_INFO "btrfsic: error, kmalloc failed!\n");
834			brelse(bh);
835			return -1;
836		}
837		/* for superblock, only the dev_bytenr makes sense */
838		superblock_tmp->dev_bytenr = dev_bytenr;
839		superblock_tmp->dev_state = dev_state;
840		superblock_tmp->logical_bytenr = dev_bytenr;
841		superblock_tmp->generation = btrfs_super_generation(super_tmp);
842		superblock_tmp->is_metadata = 1;
843		superblock_tmp->is_superblock = 1;
844		superblock_tmp->is_iodone = 1;
845		superblock_tmp->never_written = 0;
846		superblock_tmp->mirror_num = 1 + superblock_mirror_num;
847		if (state->print_mask & BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE)
848			printk_in_rcu(KERN_INFO "New initial S-block (bdev %p, %s)"
849				     " @%llu (%s/%llu/%d)\n",
850				     superblock_bdev,
851				     rcu_str_deref(device->name),
852				     (unsigned long long)dev_bytenr,
853				     dev_state->name,
854				     (unsigned long long)dev_bytenr,
855				     superblock_mirror_num);
856		list_add(&superblock_tmp->all_blocks_node,
857			 &state->all_blocks_list);
858		btrfsic_block_hashtable_add(superblock_tmp,
859					    &state->block_hashtable);
860	}
861
862	/* select the one with the highest generation field */
863	if (btrfs_super_generation(super_tmp) >
864	    state->max_superblock_generation ||
865	    0 == state->max_superblock_generation) {
866		memcpy(selected_super, super_tmp, sizeof(*selected_super));
867		*selected_dev_state = dev_state;
868		state->max_superblock_generation =
869		    btrfs_super_generation(super_tmp);
870		state->latest_superblock = superblock_tmp;
871	}
872
873	for (pass = 0; pass < 3; pass++) {
874		u64 next_bytenr;
875		int num_copies;
876		int mirror_num;
877		const char *additional_string = NULL;
878		struct btrfs_disk_key tmp_disk_key;
879
880		tmp_disk_key.type = BTRFS_ROOT_ITEM_KEY;
881		tmp_disk_key.offset = 0;
882		switch (pass) {
883		case 0:
884			tmp_disk_key.objectid =
885			    cpu_to_le64(BTRFS_ROOT_TREE_OBJECTID);
886			additional_string = "initial root ";
887			next_bytenr = btrfs_super_root(super_tmp);
888			break;
889		case 1:
890			tmp_disk_key.objectid =
891			    cpu_to_le64(BTRFS_CHUNK_TREE_OBJECTID);
892			additional_string = "initial chunk ";
893			next_bytenr = btrfs_super_chunk_root(super_tmp);
894			break;
895		case 2:
896			tmp_disk_key.objectid =
897			    cpu_to_le64(BTRFS_TREE_LOG_OBJECTID);
898			additional_string = "initial log ";
899			next_bytenr = btrfs_super_log_root(super_tmp);
900			if (0 == next_bytenr)
901				continue;
902			break;
903		}
904
905		num_copies =
906		    btrfs_num_copies(state->root->fs_info,
907				     next_bytenr, state->metablock_size);
908		if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
909			printk(KERN_INFO "num_copies(log_bytenr=%llu) = %d\n",
910			       (unsigned long long)next_bytenr, num_copies);
911		for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
912			struct btrfsic_block *next_block;
913			struct btrfsic_block_data_ctx tmp_next_block_ctx;
914			struct btrfsic_block_link *l;
915
916			if (btrfsic_map_block(state, next_bytenr,
917					      state->metablock_size,
918					      &tmp_next_block_ctx,
919					      mirror_num)) {
920				printk(KERN_INFO "btrfsic: btrfsic_map_block("
921				       "bytenr @%llu, mirror %d) failed!\n",
922				       (unsigned long long)next_bytenr,
923				       mirror_num);
924				brelse(bh);
925				return -1;
926			}
927
928			next_block = btrfsic_block_lookup_or_add(
929					state, &tmp_next_block_ctx,
930					additional_string, 1, 1, 0,
931					mirror_num, NULL);
932			if (NULL == next_block) {
933				btrfsic_release_block_ctx(&tmp_next_block_ctx);
934				brelse(bh);
935				return -1;
936			}
937
938			next_block->disk_key = tmp_disk_key;
939			next_block->generation = BTRFSIC_GENERATION_UNKNOWN;
940			l = btrfsic_block_link_lookup_or_add(
941					state, &tmp_next_block_ctx,
942					next_block, superblock_tmp,
943					BTRFSIC_GENERATION_UNKNOWN);
944			btrfsic_release_block_ctx(&tmp_next_block_ctx);
945			if (NULL == l) {
946				brelse(bh);
947				return -1;
948			}
949		}
950	}
951	if (state->print_mask & BTRFSIC_PRINT_MASK_INITIAL_ALL_TREES)
952		btrfsic_dump_tree_sub(state, superblock_tmp, 0);
953
954	brelse(bh);
955	return 0;
956}
957
958static struct btrfsic_stack_frame *btrfsic_stack_frame_alloc(void)
959{
960	struct btrfsic_stack_frame *sf;
961
962	sf = kzalloc(sizeof(*sf), GFP_NOFS);
963	if (NULL == sf)
964		printk(KERN_INFO "btrfsic: alloc memory failed!\n");
965	else
966		sf->magic = BTRFSIC_BLOCK_STACK_FRAME_MAGIC_NUMBER;
967	return sf;
968}
969
970static void btrfsic_stack_frame_free(struct btrfsic_stack_frame *sf)
971{
972	BUG_ON(!(NULL == sf ||
973		 BTRFSIC_BLOCK_STACK_FRAME_MAGIC_NUMBER == sf->magic));
974	kfree(sf);
975}
976
977static int btrfsic_process_metablock(
978		struct btrfsic_state *state,
979		struct btrfsic_block *const first_block,
980		struct btrfsic_block_data_ctx *const first_block_ctx,
981		int first_limit_nesting, int force_iodone_flag)
982{
983	struct btrfsic_stack_frame initial_stack_frame = { 0 };
984	struct btrfsic_stack_frame *sf;
985	struct btrfsic_stack_frame *next_stack;
986	struct btrfs_header *const first_hdr =
987		(struct btrfs_header *)first_block_ctx->datav[0];
988
989	BUG_ON(!first_hdr);
990	sf = &initial_stack_frame;
991	sf->error = 0;
992	sf->i = -1;
993	sf->limit_nesting = first_limit_nesting;
994	sf->block = first_block;
995	sf->block_ctx = first_block_ctx;
996	sf->next_block = NULL;
997	sf->hdr = first_hdr;
998	sf->prev = NULL;
999
1000continue_with_new_stack_frame:
1001	sf->block->generation = le64_to_cpu(sf->hdr->generation);
1002	if (0 == sf->hdr->level) {
1003		struct btrfs_leaf *const leafhdr =
1004		    (struct btrfs_leaf *)sf->hdr;
1005
1006		if (-1 == sf->i) {
1007			sf->nr = le32_to_cpu(leafhdr->header.nritems);
1008
1009			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1010				printk(KERN_INFO
1011				       "leaf %llu items %d generation %llu"
1012				       " owner %llu\n",
1013				       (unsigned long long)
1014				       sf->block_ctx->start,
1015				       sf->nr,
1016				       (unsigned long long)
1017				       le64_to_cpu(leafhdr->header.generation),
1018				       (unsigned long long)
1019				       le64_to_cpu(leafhdr->header.owner));
1020		}
1021
1022continue_with_current_leaf_stack_frame:
1023		if (0 == sf->num_copies || sf->mirror_num > sf->num_copies) {
1024			sf->i++;
1025			sf->num_copies = 0;
1026		}
1027
1028		if (sf->i < sf->nr) {
1029			struct btrfs_item disk_item;
1030			u32 disk_item_offset =
1031				(uintptr_t)(leafhdr->items + sf->i) -
1032				(uintptr_t)leafhdr;
1033			struct btrfs_disk_key *disk_key;
1034			u8 type;
1035			u32 item_offset;
1036			u32 item_size;
1037
1038			if (disk_item_offset + sizeof(struct btrfs_item) >
1039			    sf->block_ctx->len) {
1040leaf_item_out_of_bounce_error:
1041				printk(KERN_INFO
1042				       "btrfsic: leaf item out of bounce at logical %llu, dev %s\n",
1043				       sf->block_ctx->start,
1044				       sf->block_ctx->dev->name);
1045				goto one_stack_frame_backwards;
1046			}
1047			btrfsic_read_from_block_data(sf->block_ctx,
1048						     &disk_item,
1049						     disk_item_offset,
1050						     sizeof(struct btrfs_item));
1051			item_offset = le32_to_cpu(disk_item.offset);
1052			item_size = le32_to_cpu(disk_item.size);
1053			disk_key = &disk_item.key;
1054			type = disk_key->type;
1055
1056			if (BTRFS_ROOT_ITEM_KEY == type) {
1057				struct btrfs_root_item root_item;
1058				u32 root_item_offset;
1059				u64 next_bytenr;
1060
1061				root_item_offset = item_offset +
1062					offsetof(struct btrfs_leaf, items);
1063				if (root_item_offset + item_size >
1064				    sf->block_ctx->len)
1065					goto leaf_item_out_of_bounce_error;
1066				btrfsic_read_from_block_data(
1067					sf->block_ctx, &root_item,
1068					root_item_offset,
1069					item_size);
1070				next_bytenr = le64_to_cpu(root_item.bytenr);
1071
1072				sf->error =
1073				    btrfsic_create_link_to_next_block(
1074						state,
1075						sf->block,
1076						sf->block_ctx,
1077						next_bytenr,
1078						sf->limit_nesting,
1079						&sf->next_block_ctx,
1080						&sf->next_block,
1081						force_iodone_flag,
1082						&sf->num_copies,
1083						&sf->mirror_num,
1084						disk_key,
1085						le64_to_cpu(root_item.
1086						generation));
1087				if (sf->error)
1088					goto one_stack_frame_backwards;
1089
1090				if (NULL != sf->next_block) {
1091					struct btrfs_header *const next_hdr =
1092					    (struct btrfs_header *)
1093					    sf->next_block_ctx.datav[0];
1094
1095					next_stack =
1096					    btrfsic_stack_frame_alloc();
1097					if (NULL == next_stack) {
1098						btrfsic_release_block_ctx(
1099								&sf->
1100								next_block_ctx);
1101						goto one_stack_frame_backwards;
1102					}
1103
1104					next_stack->i = -1;
1105					next_stack->block = sf->next_block;
1106					next_stack->block_ctx =
1107					    &sf->next_block_ctx;
1108					next_stack->next_block = NULL;
1109					next_stack->hdr = next_hdr;
1110					next_stack->limit_nesting =
1111					    sf->limit_nesting - 1;
1112					next_stack->prev = sf;
1113					sf = next_stack;
1114					goto continue_with_new_stack_frame;
1115				}
1116			} else if (BTRFS_EXTENT_DATA_KEY == type &&
1117				   state->include_extent_data) {
1118				sf->error = btrfsic_handle_extent_data(
1119						state,
1120						sf->block,
1121						sf->block_ctx,
1122						item_offset,
1123						force_iodone_flag);
1124				if (sf->error)
1125					goto one_stack_frame_backwards;
1126			}
1127
1128			goto continue_with_current_leaf_stack_frame;
1129		}
1130	} else {
1131		struct btrfs_node *const nodehdr = (struct btrfs_node *)sf->hdr;
1132
1133		if (-1 == sf->i) {
1134			sf->nr = le32_to_cpu(nodehdr->header.nritems);
1135
1136			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1137				printk(KERN_INFO "node %llu level %d items %d"
1138				       " generation %llu owner %llu\n",
1139				       (unsigned long long)
1140				       sf->block_ctx->start,
1141				       nodehdr->header.level, sf->nr,
1142				       (unsigned long long)
1143				       le64_to_cpu(nodehdr->header.generation),
1144				       (unsigned long long)
1145				       le64_to_cpu(nodehdr->header.owner));
1146		}
1147
1148continue_with_current_node_stack_frame:
1149		if (0 == sf->num_copies || sf->mirror_num > sf->num_copies) {
1150			sf->i++;
1151			sf->num_copies = 0;
1152		}
1153
1154		if (sf->i < sf->nr) {
1155			struct btrfs_key_ptr key_ptr;
1156			u32 key_ptr_offset;
1157			u64 next_bytenr;
1158
1159			key_ptr_offset = (uintptr_t)(nodehdr->ptrs + sf->i) -
1160					  (uintptr_t)nodehdr;
1161			if (key_ptr_offset + sizeof(struct btrfs_key_ptr) >
1162			    sf->block_ctx->len) {
1163				printk(KERN_INFO
1164				       "btrfsic: node item out of bounce at logical %llu, dev %s\n",
1165				       sf->block_ctx->start,
1166				       sf->block_ctx->dev->name);
1167				goto one_stack_frame_backwards;
1168			}
1169			btrfsic_read_from_block_data(
1170				sf->block_ctx, &key_ptr, key_ptr_offset,
1171				sizeof(struct btrfs_key_ptr));
1172			next_bytenr = le64_to_cpu(key_ptr.blockptr);
1173
1174			sf->error = btrfsic_create_link_to_next_block(
1175					state,
1176					sf->block,
1177					sf->block_ctx,
1178					next_bytenr,
1179					sf->limit_nesting,
1180					&sf->next_block_ctx,
1181					&sf->next_block,
1182					force_iodone_flag,
1183					&sf->num_copies,
1184					&sf->mirror_num,
1185					&key_ptr.key,
1186					le64_to_cpu(key_ptr.generation));
1187			if (sf->error)
1188				goto one_stack_frame_backwards;
1189
1190			if (NULL != sf->next_block) {
1191				struct btrfs_header *const next_hdr =
1192				    (struct btrfs_header *)
1193				    sf->next_block_ctx.datav[0];
1194
1195				next_stack = btrfsic_stack_frame_alloc();
1196				if (NULL == next_stack)
1197					goto one_stack_frame_backwards;
1198
1199				next_stack->i = -1;
1200				next_stack->block = sf->next_block;
1201				next_stack->block_ctx = &sf->next_block_ctx;
1202				next_stack->next_block = NULL;
1203				next_stack->hdr = next_hdr;
1204				next_stack->limit_nesting =
1205				    sf->limit_nesting - 1;
1206				next_stack->prev = sf;
1207				sf = next_stack;
1208				goto continue_with_new_stack_frame;
1209			}
1210
1211			goto continue_with_current_node_stack_frame;
1212		}
1213	}
1214
1215one_stack_frame_backwards:
1216	if (NULL != sf->prev) {
1217		struct btrfsic_stack_frame *const prev = sf->prev;
1218
1219		/* the one for the initial block is freed in the caller */
1220		btrfsic_release_block_ctx(sf->block_ctx);
1221
1222		if (sf->error) {
1223			prev->error = sf->error;
1224			btrfsic_stack_frame_free(sf);
1225			sf = prev;
1226			goto one_stack_frame_backwards;
1227		}
1228
1229		btrfsic_stack_frame_free(sf);
1230		sf = prev;
1231		goto continue_with_new_stack_frame;
1232	} else {
1233		BUG_ON(&initial_stack_frame != sf);
1234	}
1235
1236	return sf->error;
1237}
1238
1239static void btrfsic_read_from_block_data(
1240	struct btrfsic_block_data_ctx *block_ctx,
1241	void *dstv, u32 offset, size_t len)
1242{
1243	size_t cur;
1244	size_t offset_in_page;
1245	char *kaddr;
1246	char *dst = (char *)dstv;
1247	size_t start_offset = block_ctx->start & ((u64)PAGE_CACHE_SIZE - 1);
1248	unsigned long i = (start_offset + offset) >> PAGE_CACHE_SHIFT;
1249
1250	WARN_ON(offset + len > block_ctx->len);
1251	offset_in_page = (start_offset + offset) &
1252			 ((unsigned long)PAGE_CACHE_SIZE - 1);
1253
1254	while (len > 0) {
1255		cur = min(len, ((size_t)PAGE_CACHE_SIZE - offset_in_page));
1256		BUG_ON(i >= (block_ctx->len + PAGE_CACHE_SIZE - 1) >>
1257			    PAGE_CACHE_SHIFT);
1258		kaddr = block_ctx->datav[i];
1259		memcpy(dst, kaddr + offset_in_page, cur);
1260
1261		dst += cur;
1262		len -= cur;
1263		offset_in_page = 0;
1264		i++;
1265	}
1266}
1267
1268static int btrfsic_create_link_to_next_block(
1269		struct btrfsic_state *state,
1270		struct btrfsic_block *block,
1271		struct btrfsic_block_data_ctx *block_ctx,
1272		u64 next_bytenr,
1273		int limit_nesting,
1274		struct btrfsic_block_data_ctx *next_block_ctx,
1275		struct btrfsic_block **next_blockp,
1276		int force_iodone_flag,
1277		int *num_copiesp, int *mirror_nump,
1278		struct btrfs_disk_key *disk_key,
1279		u64 parent_generation)
1280{
1281	struct btrfsic_block *next_block = NULL;
1282	int ret;
1283	struct btrfsic_block_link *l;
1284	int did_alloc_block_link;
1285	int block_was_created;
1286
1287	*next_blockp = NULL;
1288	if (0 == *num_copiesp) {
1289		*num_copiesp =
1290		    btrfs_num_copies(state->root->fs_info,
1291				     next_bytenr, state->metablock_size);
1292		if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
1293			printk(KERN_INFO "num_copies(log_bytenr=%llu) = %d\n",
1294			       (unsigned long long)next_bytenr, *num_copiesp);
1295		*mirror_nump = 1;
1296	}
1297
1298	if (*mirror_nump > *num_copiesp)
1299		return 0;
1300
1301	if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1302		printk(KERN_INFO
1303		       "btrfsic_create_link_to_next_block(mirror_num=%d)\n",
1304		       *mirror_nump);
1305	ret = btrfsic_map_block(state, next_bytenr,
1306				state->metablock_size,
1307				next_block_ctx, *mirror_nump);
1308	if (ret) {
1309		printk(KERN_INFO
1310		       "btrfsic: btrfsic_map_block(@%llu, mirror=%d) failed!\n",
1311		       (unsigned long long)next_bytenr, *mirror_nump);
1312		btrfsic_release_block_ctx(next_block_ctx);
1313		*next_blockp = NULL;
1314		return -1;
1315	}
1316
1317	next_block = btrfsic_block_lookup_or_add(state,
1318						 next_block_ctx, "referenced ",
1319						 1, force_iodone_flag,
1320						 !force_iodone_flag,
1321						 *mirror_nump,
1322						 &block_was_created);
1323	if (NULL == next_block) {
1324		btrfsic_release_block_ctx(next_block_ctx);
1325		*next_blockp = NULL;
1326		return -1;
1327	}
1328	if (block_was_created) {
1329		l = NULL;
1330		next_block->generation = BTRFSIC_GENERATION_UNKNOWN;
1331	} else {
1332		if (next_block->logical_bytenr != next_bytenr &&
1333		    !(!next_block->is_metadata &&
1334		      0 == next_block->logical_bytenr)) {
1335			printk(KERN_INFO
1336			       "Referenced block @%llu (%s/%llu/%d)"
1337			       " found in hash table, %c,"
1338			       " bytenr mismatch (!= stored %llu).\n",
1339			       (unsigned long long)next_bytenr,
1340			       next_block_ctx->dev->name,
1341			       (unsigned long long)next_block_ctx->dev_bytenr,
1342			       *mirror_nump,
1343			       btrfsic_get_block_type(state, next_block),
1344			       (unsigned long long)next_block->logical_bytenr);
1345		} else if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1346			printk(KERN_INFO
1347			       "Referenced block @%llu (%s/%llu/%d)"
1348			       " found in hash table, %c.\n",
1349			       (unsigned long long)next_bytenr,
1350			       next_block_ctx->dev->name,
1351			       (unsigned long long)next_block_ctx->dev_bytenr,
1352			       *mirror_nump,
1353			       btrfsic_get_block_type(state, next_block));
1354		next_block->logical_bytenr = next_bytenr;
1355
1356		next_block->mirror_num = *mirror_nump;
1357		l = btrfsic_block_link_hashtable_lookup(
1358				next_block_ctx->dev->bdev,
1359				next_block_ctx->dev_bytenr,
1360				block_ctx->dev->bdev,
1361				block_ctx->dev_bytenr,
1362				&state->block_link_hashtable);
1363	}
1364
1365	next_block->disk_key = *disk_key;
1366	if (NULL == l) {
1367		l = btrfsic_block_link_alloc();
1368		if (NULL == l) {
1369			printk(KERN_INFO "btrfsic: error, kmalloc failed!\n");
1370			btrfsic_release_block_ctx(next_block_ctx);
1371			*next_blockp = NULL;
1372			return -1;
1373		}
1374
1375		did_alloc_block_link = 1;
1376		l->block_ref_to = next_block;
1377		l->block_ref_from = block;
1378		l->ref_cnt = 1;
1379		l->parent_generation = parent_generation;
1380
1381		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1382			btrfsic_print_add_link(state, l);
1383
1384		list_add(&l->node_ref_to, &block->ref_to_list);
1385		list_add(&l->node_ref_from, &next_block->ref_from_list);
1386
1387		btrfsic_block_link_hashtable_add(l,
1388						 &state->block_link_hashtable);
1389	} else {
1390		did_alloc_block_link = 0;
1391		if (0 == limit_nesting) {
1392			l->ref_cnt++;
1393			l->parent_generation = parent_generation;
1394			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1395				btrfsic_print_add_link(state, l);
1396		}
1397	}
1398
1399	if (limit_nesting > 0 && did_alloc_block_link) {
1400		ret = btrfsic_read_block(state, next_block_ctx);
1401		if (ret < (int)next_block_ctx->len) {
1402			printk(KERN_INFO
1403			       "btrfsic: read block @logical %llu failed!\n",
1404			       (unsigned long long)next_bytenr);
1405			btrfsic_release_block_ctx(next_block_ctx);
1406			*next_blockp = NULL;
1407			return -1;
1408		}
1409
1410		*next_blockp = next_block;
1411	} else {
1412		*next_blockp = NULL;
1413	}
1414	(*mirror_nump)++;
1415
1416	return 0;
1417}
1418
1419static int btrfsic_handle_extent_data(
1420		struct btrfsic_state *state,
1421		struct btrfsic_block *block,
1422		struct btrfsic_block_data_ctx *block_ctx,
1423		u32 item_offset, int force_iodone_flag)
1424{
1425	int ret;
1426	struct btrfs_file_extent_item file_extent_item;
1427	u64 file_extent_item_offset;
1428	u64 next_bytenr;
1429	u64 num_bytes;
1430	u64 generation;
1431	struct btrfsic_block_link *l;
1432
1433	file_extent_item_offset = offsetof(struct btrfs_leaf, items) +
1434				  item_offset;
1435	if (file_extent_item_offset +
1436	    offsetof(struct btrfs_file_extent_item, disk_num_bytes) >
1437	    block_ctx->len) {
1438		printk(KERN_INFO
1439		       "btrfsic: file item out of bounce at logical %llu, dev %s\n",
1440		       block_ctx->start, block_ctx->dev->name);
1441		return -1;
1442	}
1443
1444	btrfsic_read_from_block_data(block_ctx, &file_extent_item,
1445		file_extent_item_offset,
1446		offsetof(struct btrfs_file_extent_item, disk_num_bytes));
1447	if (BTRFS_FILE_EXTENT_REG != file_extent_item.type ||
1448	    ((u64)0) == le64_to_cpu(file_extent_item.disk_bytenr)) {
1449		if (state->print_mask & BTRFSIC_PRINT_MASK_VERY_VERBOSE)
1450			printk(KERN_INFO "extent_data: type %u, disk_bytenr = %llu\n",
1451			       file_extent_item.type,
1452			       (unsigned long long)
1453			       le64_to_cpu(file_extent_item.disk_bytenr));
1454		return 0;
1455	}
1456
1457	if (file_extent_item_offset + sizeof(struct btrfs_file_extent_item) >
1458	    block_ctx->len) {
1459		printk(KERN_INFO
1460		       "btrfsic: file item out of bounce at logical %llu, dev %s\n",
1461		       block_ctx->start, block_ctx->dev->name);
1462		return -1;
1463	}
1464	btrfsic_read_from_block_data(block_ctx, &file_extent_item,
1465				     file_extent_item_offset,
1466				     sizeof(struct btrfs_file_extent_item));
1467	next_bytenr = le64_to_cpu(file_extent_item.disk_bytenr) +
1468		      le64_to_cpu(file_extent_item.offset);
1469	generation = le64_to_cpu(file_extent_item.generation);
1470	num_bytes = le64_to_cpu(file_extent_item.num_bytes);
1471	generation = le64_to_cpu(file_extent_item.generation);
1472
1473	if (state->print_mask & BTRFSIC_PRINT_MASK_VERY_VERBOSE)
1474		printk(KERN_INFO "extent_data: type %u, disk_bytenr = %llu,"
1475		       " offset = %llu, num_bytes = %llu\n",
1476		       file_extent_item.type,
1477		       (unsigned long long)
1478		       le64_to_cpu(file_extent_item.disk_bytenr),
1479		       (unsigned long long)le64_to_cpu(file_extent_item.offset),
1480		       (unsigned long long)num_bytes);
1481	while (num_bytes > 0) {
1482		u32 chunk_len;
1483		int num_copies;
1484		int mirror_num;
1485
1486		if (num_bytes > state->datablock_size)
1487			chunk_len = state->datablock_size;
1488		else
1489			chunk_len = num_bytes;
1490
1491		num_copies =
1492		    btrfs_num_copies(state->root->fs_info,
1493				     next_bytenr, state->datablock_size);
1494		if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
1495			printk(KERN_INFO "num_copies(log_bytenr=%llu) = %d\n",
1496			       (unsigned long long)next_bytenr, num_copies);
1497		for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
1498			struct btrfsic_block_data_ctx next_block_ctx;
1499			struct btrfsic_block *next_block;
1500			int block_was_created;
1501
1502			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1503				printk(KERN_INFO "btrfsic_handle_extent_data("
1504				       "mirror_num=%d)\n", mirror_num);
1505			if (state->print_mask & BTRFSIC_PRINT_MASK_VERY_VERBOSE)
1506				printk(KERN_INFO
1507				       "\tdisk_bytenr = %llu, num_bytes %u\n",
1508				       (unsigned long long)next_bytenr,
1509				       chunk_len);
1510			ret = btrfsic_map_block(state, next_bytenr,
1511						chunk_len, &next_block_ctx,
1512						mirror_num);
1513			if (ret) {
1514				printk(KERN_INFO
1515				       "btrfsic: btrfsic_map_block(@%llu,"
1516				       " mirror=%d) failed!\n",
1517				       (unsigned long long)next_bytenr,
1518				       mirror_num);
1519				return -1;
1520			}
1521
1522			next_block = btrfsic_block_lookup_or_add(
1523					state,
1524					&next_block_ctx,
1525					"referenced ",
1526					0,
1527					force_iodone_flag,
1528					!force_iodone_flag,
1529					mirror_num,
1530					&block_was_created);
1531			if (NULL == next_block) {
1532				printk(KERN_INFO
1533				       "btrfsic: error, kmalloc failed!\n");
1534				btrfsic_release_block_ctx(&next_block_ctx);
1535				return -1;
1536			}
1537			if (!block_was_created) {
1538				if (next_block->logical_bytenr != next_bytenr &&
1539				    !(!next_block->is_metadata &&
1540				      0 == next_block->logical_bytenr)) {
1541					printk(KERN_INFO
1542					       "Referenced block"
1543					       " @%llu (%s/%llu/%d)"
1544					       " found in hash table, D,"
1545					       " bytenr mismatch"
1546					       " (!= stored %llu).\n",
1547					       (unsigned long long)next_bytenr,
1548					       next_block_ctx.dev->name,
1549					       (unsigned long long)
1550					       next_block_ctx.dev_bytenr,
1551					       mirror_num,
1552					       (unsigned long long)
1553					       next_block->logical_bytenr);
1554				}
1555				next_block->logical_bytenr = next_bytenr;
1556				next_block->mirror_num = mirror_num;
1557			}
1558
1559			l = btrfsic_block_link_lookup_or_add(state,
1560							     &next_block_ctx,
1561							     next_block, block,
1562							     generation);
1563			btrfsic_release_block_ctx(&next_block_ctx);
1564			if (NULL == l)
1565				return -1;
1566		}
1567
1568		next_bytenr += chunk_len;
1569		num_bytes -= chunk_len;
1570	}
1571
1572	return 0;
1573}
1574
1575static int btrfsic_map_block(struct btrfsic_state *state, u64 bytenr, u32 len,
1576			     struct btrfsic_block_data_ctx *block_ctx_out,
1577			     int mirror_num)
1578{
1579	int ret;
1580	u64 length;
1581	struct btrfs_bio *multi = NULL;
1582	struct btrfs_device *device;
1583
1584	length = len;
1585	ret = btrfs_map_block(&state->root->fs_info->mapping_tree, READ,
1586			      bytenr, &length, &multi, mirror_num);
1587
1588	device = multi->stripes[0].dev;
1589	block_ctx_out->dev = btrfsic_dev_state_lookup(device->bdev);
1590	block_ctx_out->dev_bytenr = multi->stripes[0].physical;
1591	block_ctx_out->start = bytenr;
1592	block_ctx_out->len = len;
1593	block_ctx_out->datav = NULL;
1594	block_ctx_out->pagev = NULL;
1595	block_ctx_out->mem_to_free = NULL;
1596
1597	if (0 == ret)
1598		kfree(multi);
1599	if (NULL == block_ctx_out->dev) {
1600		ret = -ENXIO;
1601		printk(KERN_INFO "btrfsic: error, cannot lookup dev (#1)!\n");
1602	}
1603
1604	return ret;
1605}
1606
1607static int btrfsic_map_superblock(struct btrfsic_state *state, u64 bytenr,
1608				  u32 len, struct block_device *bdev,
1609				  struct btrfsic_block_data_ctx *block_ctx_out)
1610{
1611	block_ctx_out->dev = btrfsic_dev_state_lookup(bdev);
1612	block_ctx_out->dev_bytenr = bytenr;
1613	block_ctx_out->start = bytenr;
1614	block_ctx_out->len = len;
1615	block_ctx_out->datav = NULL;
1616	block_ctx_out->pagev = NULL;
1617	block_ctx_out->mem_to_free = NULL;
1618	if (NULL != block_ctx_out->dev) {
1619		return 0;
1620	} else {
1621		printk(KERN_INFO "btrfsic: error, cannot lookup dev (#2)!\n");
1622		return -ENXIO;
1623	}
1624}
1625
1626static void btrfsic_release_block_ctx(struct btrfsic_block_data_ctx *block_ctx)
1627{
1628	if (block_ctx->mem_to_free) {
1629		unsigned int num_pages;
1630
1631		BUG_ON(!block_ctx->datav);
1632		BUG_ON(!block_ctx->pagev);
1633		num_pages = (block_ctx->len + (u64)PAGE_CACHE_SIZE - 1) >>
1634			    PAGE_CACHE_SHIFT;
1635		while (num_pages > 0) {
1636			num_pages--;
1637			if (block_ctx->datav[num_pages]) {
1638				kunmap(block_ctx->pagev[num_pages]);
1639				block_ctx->datav[num_pages] = NULL;
1640			}
1641			if (block_ctx->pagev[num_pages]) {
1642				__free_page(block_ctx->pagev[num_pages]);
1643				block_ctx->pagev[num_pages] = NULL;
1644			}
1645		}
1646
1647		kfree(block_ctx->mem_to_free);
1648		block_ctx->mem_to_free = NULL;
1649		block_ctx->pagev = NULL;
1650		block_ctx->datav = NULL;
1651	}
1652}
1653
1654static int btrfsic_read_block(struct btrfsic_state *state,
1655			      struct btrfsic_block_data_ctx *block_ctx)
1656{
1657	unsigned int num_pages;
1658	unsigned int i;
1659	u64 dev_bytenr;
1660	int ret;
1661
1662	BUG_ON(block_ctx->datav);
1663	BUG_ON(block_ctx->pagev);
1664	BUG_ON(block_ctx->mem_to_free);
1665	if (block_ctx->dev_bytenr & ((u64)PAGE_CACHE_SIZE - 1)) {
1666		printk(KERN_INFO
1667		       "btrfsic: read_block() with unaligned bytenr %llu\n",
1668		       (unsigned long long)block_ctx->dev_bytenr);
1669		return -1;
1670	}
1671
1672	num_pages = (block_ctx->len + (u64)PAGE_CACHE_SIZE - 1) >>
1673		    PAGE_CACHE_SHIFT;
1674	block_ctx->mem_to_free = kzalloc((sizeof(*block_ctx->datav) +
1675					  sizeof(*block_ctx->pagev)) *
1676					 num_pages, GFP_NOFS);
1677	if (!block_ctx->mem_to_free)
1678		return -1;
1679	block_ctx->datav = block_ctx->mem_to_free;
1680	block_ctx->pagev = (struct page **)(block_ctx->datav + num_pages);
1681	for (i = 0; i < num_pages; i++) {
1682		block_ctx->pagev[i] = alloc_page(GFP_NOFS);
1683		if (!block_ctx->pagev[i])
1684			return -1;
1685	}
1686
1687	dev_bytenr = block_ctx->dev_bytenr;
1688	for (i = 0; i < num_pages;) {
1689		struct bio *bio;
1690		unsigned int j;
1691		DECLARE_COMPLETION_ONSTACK(complete);
1692
1693		bio = bio_alloc(GFP_NOFS, num_pages - i);
1694		if (!bio) {
1695			printk(KERN_INFO
1696			       "btrfsic: bio_alloc() for %u pages failed!\n",
1697			       num_pages - i);
1698			return -1;
1699		}
1700		bio->bi_bdev = block_ctx->dev->bdev;
1701		bio->bi_sector = dev_bytenr >> 9;
1702		bio->bi_end_io = btrfsic_complete_bio_end_io;
1703		bio->bi_private = &complete;
1704
1705		for (j = i; j < num_pages; j++) {
1706			ret = bio_add_page(bio, block_ctx->pagev[j],
1707					   PAGE_CACHE_SIZE, 0);
1708			if (PAGE_CACHE_SIZE != ret)
1709				break;
1710		}
1711		if (j == i) {
1712			printk(KERN_INFO
1713			       "btrfsic: error, failed to add a single page!\n");
1714			return -1;
1715		}
1716		submit_bio(READ, bio);
1717
1718		/* this will also unplug the queue */
1719		wait_for_completion(&complete);
1720
1721		if (!test_bit(BIO_UPTODATE, &bio->bi_flags)) {
1722			printk(KERN_INFO
1723			       "btrfsic: read error at logical %llu dev %s!\n",
1724			       block_ctx->start, block_ctx->dev->name);
1725			bio_put(bio);
1726			return -1;
1727		}
1728		bio_put(bio);
1729		dev_bytenr += (j - i) * PAGE_CACHE_SIZE;
1730		i = j;
1731	}
1732	for (i = 0; i < num_pages; i++) {
1733		block_ctx->datav[i] = kmap(block_ctx->pagev[i]);
1734		if (!block_ctx->datav[i]) {
1735			printk(KERN_INFO "btrfsic: kmap() failed (dev %s)!\n",
1736			       block_ctx->dev->name);
1737			return -1;
1738		}
1739	}
1740
1741	return block_ctx->len;
1742}
1743
1744static void btrfsic_complete_bio_end_io(struct bio *bio, int err)
1745{
1746	complete((struct completion *)bio->bi_private);
1747}
1748
1749static void btrfsic_dump_database(struct btrfsic_state *state)
1750{
1751	struct list_head *elem_all;
1752
1753	BUG_ON(NULL == state);
1754
1755	printk(KERN_INFO "all_blocks_list:\n");
1756	list_for_each(elem_all, &state->all_blocks_list) {
1757		const struct btrfsic_block *const b_all =
1758		    list_entry(elem_all, struct btrfsic_block,
1759			       all_blocks_node);
1760		struct list_head *elem_ref_to;
1761		struct list_head *elem_ref_from;
1762
1763		printk(KERN_INFO "%c-block @%llu (%s/%llu/%d)\n",
1764		       btrfsic_get_block_type(state, b_all),
1765		       (unsigned long long)b_all->logical_bytenr,
1766		       b_all->dev_state->name,
1767		       (unsigned long long)b_all->dev_bytenr,
1768		       b_all->mirror_num);
1769
1770		list_for_each(elem_ref_to, &b_all->ref_to_list) {
1771			const struct btrfsic_block_link *const l =
1772			    list_entry(elem_ref_to,
1773				       struct btrfsic_block_link,
1774				       node_ref_to);
1775
1776			printk(KERN_INFO " %c @%llu (%s/%llu/%d)"
1777			       " refers %u* to"
1778			       " %c @%llu (%s/%llu/%d)\n",
1779			       btrfsic_get_block_type(state, b_all),
1780			       (unsigned long long)b_all->logical_bytenr,
1781			       b_all->dev_state->name,
1782			       (unsigned long long)b_all->dev_bytenr,
1783			       b_all->mirror_num,
1784			       l->ref_cnt,
1785			       btrfsic_get_block_type(state, l->block_ref_to),
1786			       (unsigned long long)
1787			       l->block_ref_to->logical_bytenr,
1788			       l->block_ref_to->dev_state->name,
1789			       (unsigned long long)l->block_ref_to->dev_bytenr,
1790			       l->block_ref_to->mirror_num);
1791		}
1792
1793		list_for_each(elem_ref_from, &b_all->ref_from_list) {
1794			const struct btrfsic_block_link *const l =
1795			    list_entry(elem_ref_from,
1796				       struct btrfsic_block_link,
1797				       node_ref_from);
1798
1799			printk(KERN_INFO " %c @%llu (%s/%llu/%d)"
1800			       " is ref %u* from"
1801			       " %c @%llu (%s/%llu/%d)\n",
1802			       btrfsic_get_block_type(state, b_all),
1803			       (unsigned long long)b_all->logical_bytenr,
1804			       b_all->dev_state->name,
1805			       (unsigned long long)b_all->dev_bytenr,
1806			       b_all->mirror_num,
1807			       l->ref_cnt,
1808			       btrfsic_get_block_type(state, l->block_ref_from),
1809			       (unsigned long long)
1810			       l->block_ref_from->logical_bytenr,
1811			       l->block_ref_from->dev_state->name,
1812			       (unsigned long long)
1813			       l->block_ref_from->dev_bytenr,
1814			       l->block_ref_from->mirror_num);
1815		}
1816
1817		printk(KERN_INFO "\n");
1818	}
1819}
1820
1821/*
1822 * Test whether the disk block contains a tree block (leaf or node)
1823 * (note that this test fails for the super block)
1824 */
1825static int btrfsic_test_for_metadata(struct btrfsic_state *state,
1826				     char **datav, unsigned int num_pages)
1827{
1828	struct btrfs_header *h;
1829	u8 csum[BTRFS_CSUM_SIZE];
1830	u32 crc = ~(u32)0;
1831	unsigned int i;
1832
1833	if (num_pages * PAGE_CACHE_SIZE < state->metablock_size)
1834		return 1; /* not metadata */
1835	num_pages = state->metablock_size >> PAGE_CACHE_SHIFT;
1836	h = (struct btrfs_header *)datav[0];
1837
1838	if (memcmp(h->fsid, state->root->fs_info->fsid, BTRFS_UUID_SIZE))
1839		return 1;
1840
1841	for (i = 0; i < num_pages; i++) {
1842		u8 *data = i ? datav[i] : (datav[i] + BTRFS_CSUM_SIZE);
1843		size_t sublen = i ? PAGE_CACHE_SIZE :
1844				    (PAGE_CACHE_SIZE - BTRFS_CSUM_SIZE);
1845
1846		crc = crc32c(crc, data, sublen);
1847	}
1848	btrfs_csum_final(crc, csum);
1849	if (memcmp(csum, h->csum, state->csum_size))
1850		return 1;
1851
1852	return 0; /* is metadata */
1853}
1854
1855static void btrfsic_process_written_block(struct btrfsic_dev_state *dev_state,
1856					  u64 dev_bytenr, char **mapped_datav,
1857					  unsigned int num_pages,
1858					  struct bio *bio, int *bio_is_patched,
1859					  struct buffer_head *bh,
1860					  int submit_bio_bh_rw)
1861{
1862	int is_metadata;
1863	struct btrfsic_block *block;
1864	struct btrfsic_block_data_ctx block_ctx;
1865	int ret;
1866	struct btrfsic_state *state = dev_state->state;
1867	struct block_device *bdev = dev_state->bdev;
1868	unsigned int processed_len;
1869
1870	if (NULL != bio_is_patched)
1871		*bio_is_patched = 0;
1872
1873again:
1874	if (num_pages == 0)
1875		return;
1876
1877	processed_len = 0;
1878	is_metadata = (0 == btrfsic_test_for_metadata(state, mapped_datav,
1879						      num_pages));
1880
1881	block = btrfsic_block_hashtable_lookup(bdev, dev_bytenr,
1882					       &state->block_hashtable);
1883	if (NULL != block) {
1884		u64 bytenr = 0;
1885		struct list_head *elem_ref_to;
1886		struct list_head *tmp_ref_to;
1887
1888		if (block->is_superblock) {
1889			bytenr = le64_to_cpu(((struct btrfs_super_block *)
1890					      mapped_datav[0])->bytenr);
1891			if (num_pages * PAGE_CACHE_SIZE <
1892			    BTRFS_SUPER_INFO_SIZE) {
1893				printk(KERN_INFO
1894				       "btrfsic: cannot work with too short bios!\n");
1895				return;
1896			}
1897			is_metadata = 1;
1898			BUG_ON(BTRFS_SUPER_INFO_SIZE & (PAGE_CACHE_SIZE - 1));
1899			processed_len = BTRFS_SUPER_INFO_SIZE;
1900			if (state->print_mask &
1901			    BTRFSIC_PRINT_MASK_TREE_BEFORE_SB_WRITE) {
1902				printk(KERN_INFO
1903				       "[before new superblock is written]:\n");
1904				btrfsic_dump_tree_sub(state, block, 0);
1905			}
1906		}
1907		if (is_metadata) {
1908			if (!block->is_superblock) {
1909				if (num_pages * PAGE_CACHE_SIZE <
1910				    state->metablock_size) {
1911					printk(KERN_INFO
1912					       "btrfsic: cannot work with too short bios!\n");
1913					return;
1914				}
1915				processed_len = state->metablock_size;
1916				bytenr = le64_to_cpu(((struct btrfs_header *)
1917						      mapped_datav[0])->bytenr);
1918				btrfsic_cmp_log_and_dev_bytenr(state, bytenr,
1919							       dev_state,
1920							       dev_bytenr);
1921			}
1922			if (block->logical_bytenr != bytenr) {
1923				printk(KERN_INFO
1924				       "Written block @%llu (%s/%llu/%d)"
1925				       " found in hash table, %c,"
1926				       " bytenr mismatch"
1927				       " (!= stored %llu).\n",
1928				       (unsigned long long)bytenr,
1929				       dev_state->name,
1930				       (unsigned long long)dev_bytenr,
1931				       block->mirror_num,
1932				       btrfsic_get_block_type(state, block),
1933				       (unsigned long long)
1934				       block->logical_bytenr);
1935				block->logical_bytenr = bytenr;
1936			} else if (state->print_mask &
1937				   BTRFSIC_PRINT_MASK_VERBOSE)
1938				printk(KERN_INFO
1939				       "Written block @%llu (%s/%llu/%d)"
1940				       " found in hash table, %c.\n",
1941				       (unsigned long long)bytenr,
1942				       dev_state->name,
1943				       (unsigned long long)dev_bytenr,
1944				       block->mirror_num,
1945				       btrfsic_get_block_type(state, block));
1946		} else {
1947			if (num_pages * PAGE_CACHE_SIZE <
1948			    state->datablock_size) {
1949				printk(KERN_INFO
1950				       "btrfsic: cannot work with too short bios!\n");
1951				return;
1952			}
1953			processed_len = state->datablock_size;
1954			bytenr = block->logical_bytenr;
1955			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1956				printk(KERN_INFO
1957				       "Written block @%llu (%s/%llu/%d)"
1958				       " found in hash table, %c.\n",
1959				       (unsigned long long)bytenr,
1960				       dev_state->name,
1961				       (unsigned long long)dev_bytenr,
1962				       block->mirror_num,
1963				       btrfsic_get_block_type(state, block));
1964		}
1965
1966		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1967			printk(KERN_INFO
1968			       "ref_to_list: %cE, ref_from_list: %cE\n",
1969			       list_empty(&block->ref_to_list) ? ' ' : '!',
1970			       list_empty(&block->ref_from_list) ? ' ' : '!');
1971		if (btrfsic_is_block_ref_by_superblock(state, block, 0)) {
1972			printk(KERN_INFO "btrfs: attempt to overwrite %c-block"
1973			       " @%llu (%s/%llu/%d), old(gen=%llu,"
1974			       " objectid=%llu, type=%d, offset=%llu),"
1975			       " new(gen=%llu),"
1976			       " which is referenced by most recent superblock"
1977			       " (superblockgen=%llu)!\n",
1978			       btrfsic_get_block_type(state, block),
1979			       (unsigned long long)bytenr,
1980			       dev_state->name,
1981			       (unsigned long long)dev_bytenr,
1982			       block->mirror_num,
1983			       (unsigned long long)block->generation,
1984			       (unsigned long long)
1985			       le64_to_cpu(block->disk_key.objectid),
1986			       block->disk_key.type,
1987			       (unsigned long long)
1988			       le64_to_cpu(block->disk_key.offset),
1989			       (unsigned long long)
1990			       le64_to_cpu(((struct btrfs_header *)
1991					    mapped_datav[0])->generation),
1992			       (unsigned long long)
1993			       state->max_superblock_generation);
1994			btrfsic_dump_tree(state);
1995		}
1996
1997		if (!block->is_iodone && !block->never_written) {
1998			printk(KERN_INFO "btrfs: attempt to overwrite %c-block"
1999			       " @%llu (%s/%llu/%d), oldgen=%llu, newgen=%llu,"
2000			       " which is not yet iodone!\n",
2001			       btrfsic_get_block_type(state, block),
2002			       (unsigned long long)bytenr,
2003			       dev_state->name,
2004			       (unsigned long long)dev_bytenr,
2005			       block->mirror_num,
2006			       (unsigned long long)block->generation,
2007			       (unsigned long long)
2008			       le64_to_cpu(((struct btrfs_header *)
2009					    mapped_datav[0])->generation));
2010			/* it would not be safe to go on */
2011			btrfsic_dump_tree(state);
2012			goto continue_loop;
2013		}
2014
2015		/*
2016		 * Clear all references of this block. Do not free
2017		 * the block itself even if is not referenced anymore
2018		 * because it still carries valueable information
2019		 * like whether it was ever written and IO completed.
2020		 */
2021		list_for_each_safe(elem_ref_to, tmp_ref_to,
2022				   &block->ref_to_list) {
2023			struct btrfsic_block_link *const l =
2024			    list_entry(elem_ref_to,
2025				       struct btrfsic_block_link,
2026				       node_ref_to);
2027
2028			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2029				btrfsic_print_rem_link(state, l);
2030			l->ref_cnt--;
2031			if (0 == l->ref_cnt) {
2032				list_del(&l->node_ref_to);
2033				list_del(&l->node_ref_from);
2034				btrfsic_block_link_hashtable_remove(l);
2035				btrfsic_block_link_free(l);
2036			}
2037		}
2038
2039		if (block->is_superblock)
2040			ret = btrfsic_map_superblock(state, bytenr,
2041						     processed_len,
2042						     bdev, &block_ctx);
2043		else
2044			ret = btrfsic_map_block(state, bytenr, processed_len,
2045						&block_ctx, 0);
2046		if (ret) {
2047			printk(KERN_INFO
2048			       "btrfsic: btrfsic_map_block(root @%llu)"
2049			       " failed!\n", (unsigned long long)bytenr);
2050			goto continue_loop;
2051		}
2052		block_ctx.datav = mapped_datav;
2053		/* the following is required in case of writes to mirrors,
2054		 * use the same that was used for the lookup */
2055		block_ctx.dev = dev_state;
2056		block_ctx.dev_bytenr = dev_bytenr;
2057
2058		if (is_metadata || state->include_extent_data) {
2059			block->never_written = 0;
2060			block->iodone_w_error = 0;
2061			if (NULL != bio) {
2062				block->is_iodone = 0;
2063				BUG_ON(NULL == bio_is_patched);
2064				if (!*bio_is_patched) {
2065					block->orig_bio_bh_private =
2066					    bio->bi_private;
2067					block->orig_bio_bh_end_io.bio =
2068					    bio->bi_end_io;
2069					block->next_in_same_bio = NULL;
2070					bio->bi_private = block;
2071					bio->bi_end_io = btrfsic_bio_end_io;
2072					*bio_is_patched = 1;
2073				} else {
2074					struct btrfsic_block *chained_block =
2075					    (struct btrfsic_block *)
2076					    bio->bi_private;
2077
2078					BUG_ON(NULL == chained_block);
2079					block->orig_bio_bh_private =
2080					    chained_block->orig_bio_bh_private;
2081					block->orig_bio_bh_end_io.bio =
2082					    chained_block->orig_bio_bh_end_io.
2083					    bio;
2084					block->next_in_same_bio = chained_block;
2085					bio->bi_private = block;
2086				}
2087			} else if (NULL != bh) {
2088				block->is_iodone = 0;
2089				block->orig_bio_bh_private = bh->b_private;
2090				block->orig_bio_bh_end_io.bh = bh->b_end_io;
2091				block->next_in_same_bio = NULL;
2092				bh->b_private = block;
2093				bh->b_end_io = btrfsic_bh_end_io;
2094			} else {
2095				block->is_iodone = 1;
2096				block->orig_bio_bh_private = NULL;
2097				block->orig_bio_bh_end_io.bio = NULL;
2098				block->next_in_same_bio = NULL;
2099			}
2100		}
2101
2102		block->flush_gen = dev_state->last_flush_gen + 1;
2103		block->submit_bio_bh_rw = submit_bio_bh_rw;
2104		if (is_metadata) {
2105			block->logical_bytenr = bytenr;
2106			block->is_metadata = 1;
2107			if (block->is_superblock) {
2108				BUG_ON(PAGE_CACHE_SIZE !=
2109				       BTRFS_SUPER_INFO_SIZE);
2110				ret = btrfsic_process_written_superblock(
2111						state,
2112						block,
2113						(struct btrfs_super_block *)
2114						mapped_datav[0]);
2115				if (state->print_mask &
2116				    BTRFSIC_PRINT_MASK_TREE_AFTER_SB_WRITE) {
2117					printk(KERN_INFO
2118					"[after new superblock is written]:\n");
2119					btrfsic_dump_tree_sub(state, block, 0);
2120				}
2121			} else {
2122				block->mirror_num = 0;	/* unknown */
2123				ret = btrfsic_process_metablock(
2124						state,
2125						block,
2126						&block_ctx,
2127						0, 0);
2128			}
2129			if (ret)
2130				printk(KERN_INFO
2131				       "btrfsic: btrfsic_process_metablock"
2132				       "(root @%llu) failed!\n",
2133				       (unsigned long long)dev_bytenr);
2134		} else {
2135			block->is_metadata = 0;
2136			block->mirror_num = 0;	/* unknown */
2137			block->generation = BTRFSIC_GENERATION_UNKNOWN;
2138			if (!state->include_extent_data
2139			    && list_empty(&block->ref_from_list)) {
2140				/*
2141				 * disk block is overwritten with extent
2142				 * data (not meta data) and we are configured
2143				 * to not include extent data: take the
2144				 * chance and free the block's memory
2145				 */
2146				btrfsic_block_hashtable_remove(block);
2147				list_del(&block->all_blocks_node);
2148				btrfsic_block_free(block);
2149			}
2150		}
2151		btrfsic_release_block_ctx(&block_ctx);
2152	} else {
2153		/* block has not been found in hash table */
2154		u64 bytenr;
2155
2156		if (!is_metadata) {
2157			processed_len = state->datablock_size;
2158			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2159				printk(KERN_INFO "Written block (%s/%llu/?)"
2160				       " !found in hash table, D.\n",
2161				       dev_state->name,
2162				       (unsigned long long)dev_bytenr);
2163			if (!state->include_extent_data) {
2164				/* ignore that written D block */
2165				goto continue_loop;
2166			}
2167
2168			/* this is getting ugly for the
2169			 * include_extent_data case... */
2170			bytenr = 0;	/* unknown */
2171			block_ctx.start = bytenr;
2172			block_ctx.len = processed_len;
2173			block_ctx.mem_to_free = NULL;
2174			block_ctx.pagev = NULL;
2175		} else {
2176			processed_len = state->metablock_size;
2177			bytenr = le64_to_cpu(((struct btrfs_header *)
2178					      mapped_datav[0])->bytenr);
2179			btrfsic_cmp_log_and_dev_bytenr(state, bytenr, dev_state,
2180						       dev_bytenr);
2181			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2182				printk(KERN_INFO
2183				       "Written block @%llu (%s/%llu/?)"
2184				       " !found in hash table, M.\n",
2185				       (unsigned long long)bytenr,
2186				       dev_state->name,
2187				       (unsigned long long)dev_bytenr);
2188
2189			ret = btrfsic_map_block(state, bytenr, processed_len,
2190						&block_ctx, 0);
2191			if (ret) {
2192				printk(KERN_INFO
2193				       "btrfsic: btrfsic_map_block(root @%llu)"
2194				       " failed!\n",
2195				       (unsigned long long)dev_bytenr);
2196				goto continue_loop;
2197			}
2198		}
2199		block_ctx.datav = mapped_datav;
2200		/* the following is required in case of writes to mirrors,
2201		 * use the same that was used for the lookup */
2202		block_ctx.dev = dev_state;
2203		block_ctx.dev_bytenr = dev_bytenr;
2204
2205		block = btrfsic_block_alloc();
2206		if (NULL == block) {
2207			printk(KERN_INFO "btrfsic: error, kmalloc failed!\n");
2208			btrfsic_release_block_ctx(&block_ctx);
2209			goto continue_loop;
2210		}
2211		block->dev_state = dev_state;
2212		block->dev_bytenr = dev_bytenr;
2213		block->logical_bytenr = bytenr;
2214		block->is_metadata = is_metadata;
2215		block->never_written = 0;
2216		block->iodone_w_error = 0;
2217		block->mirror_num = 0;	/* unknown */
2218		block->flush_gen = dev_state->last_flush_gen + 1;
2219		block->submit_bio_bh_rw = submit_bio_bh_rw;
2220		if (NULL != bio) {
2221			block->is_iodone = 0;
2222			BUG_ON(NULL == bio_is_patched);
2223			if (!*bio_is_patched) {
2224				block->orig_bio_bh_private = bio->bi_private;
2225				block->orig_bio_bh_end_io.bio = bio->bi_end_io;
2226				block->next_in_same_bio = NULL;
2227				bio->bi_private = block;
2228				bio->bi_end_io = btrfsic_bio_end_io;
2229				*bio_is_patched = 1;
2230			} else {
2231				struct btrfsic_block *chained_block =
2232				    (struct btrfsic_block *)
2233				    bio->bi_private;
2234
2235				BUG_ON(NULL == chained_block);
2236				block->orig_bio_bh_private =
2237				    chained_block->orig_bio_bh_private;
2238				block->orig_bio_bh_end_io.bio =
2239				    chained_block->orig_bio_bh_end_io.bio;
2240				block->next_in_same_bio = chained_block;
2241				bio->bi_private = block;
2242			}
2243		} else if (NULL != bh) {
2244			block->is_iodone = 0;
2245			block->orig_bio_bh_private = bh->b_private;
2246			block->orig_bio_bh_end_io.bh = bh->b_end_io;
2247			block->next_in_same_bio = NULL;
2248			bh->b_private = block;
2249			bh->b_end_io = btrfsic_bh_end_io;
2250		} else {
2251			block->is_iodone = 1;
2252			block->orig_bio_bh_private = NULL;
2253			block->orig_bio_bh_end_io.bio = NULL;
2254			block->next_in_same_bio = NULL;
2255		}
2256		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2257			printk(KERN_INFO
2258			       "New written %c-block @%llu (%s/%llu/%d)\n",
2259			       is_metadata ? 'M' : 'D',
2260			       (unsigned long long)block->logical_bytenr,
2261			       block->dev_state->name,
2262			       (unsigned long long)block->dev_bytenr,
2263			       block->mirror_num);
2264		list_add(&block->all_blocks_node, &state->all_blocks_list);
2265		btrfsic_block_hashtable_add(block, &state->block_hashtable);
2266
2267		if (is_metadata) {
2268			ret = btrfsic_process_metablock(state, block,
2269							&block_ctx, 0, 0);
2270			if (ret)
2271				printk(KERN_INFO
2272				       "btrfsic: process_metablock(root @%llu)"
2273				       " failed!\n",
2274				       (unsigned long long)dev_bytenr);
2275		}
2276		btrfsic_release_block_ctx(&block_ctx);
2277	}
2278
2279continue_loop:
2280	BUG_ON(!processed_len);
2281	dev_bytenr += processed_len;
2282	mapped_datav += processed_len >> PAGE_CACHE_SHIFT;
2283	num_pages -= processed_len >> PAGE_CACHE_SHIFT;
2284	goto again;
2285}
2286
2287static void btrfsic_bio_end_io(struct bio *bp, int bio_error_status)
2288{
2289	struct btrfsic_block *block = (struct btrfsic_block *)bp->bi_private;
2290	int iodone_w_error;
2291
2292	/* mutex is not held! This is not save if IO is not yet completed
2293	 * on umount */
2294	iodone_w_error = 0;
2295	if (bio_error_status)
2296		iodone_w_error = 1;
2297
2298	BUG_ON(NULL == block);
2299	bp->bi_private = block->orig_bio_bh_private;
2300	bp->bi_end_io = block->orig_bio_bh_end_io.bio;
2301
2302	do {
2303		struct btrfsic_block *next_block;
2304		struct btrfsic_dev_state *const dev_state = block->dev_state;
2305
2306		if ((dev_state->state->print_mask &
2307		     BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2308			printk(KERN_INFO
2309			       "bio_end_io(err=%d) for %c @%llu (%s/%llu/%d)\n",
2310			       bio_error_status,
2311			       btrfsic_get_block_type(dev_state->state, block),
2312			       (unsigned long long)block->logical_bytenr,
2313			       dev_state->name,
2314			       (unsigned long long)block->dev_bytenr,
2315			       block->mirror_num);
2316		next_block = block->next_in_same_bio;
2317		block->iodone_w_error = iodone_w_error;
2318		if (block->submit_bio_bh_rw & REQ_FLUSH) {
2319			dev_state->last_flush_gen++;
2320			if ((dev_state->state->print_mask &
2321			     BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2322				printk(KERN_INFO
2323				       "bio_end_io() new %s flush_gen=%llu\n",
2324				       dev_state->name,
2325				       (unsigned long long)
2326				       dev_state->last_flush_gen);
2327		}
2328		if (block->submit_bio_bh_rw & REQ_FUA)
2329			block->flush_gen = 0; /* FUA completed means block is
2330					       * on disk */
2331		block->is_iodone = 1; /* for FLUSH, this releases the block */
2332		block = next_block;
2333	} while (NULL != block);
2334
2335	bp->bi_end_io(bp, bio_error_status);
2336}
2337
2338static void btrfsic_bh_end_io(struct buffer_head *bh, int uptodate)
2339{
2340	struct btrfsic_block *block = (struct btrfsic_block *)bh->b_private;
2341	int iodone_w_error = !uptodate;
2342	struct btrfsic_dev_state *dev_state;
2343
2344	BUG_ON(NULL == block);
2345	dev_state = block->dev_state;
2346	if ((dev_state->state->print_mask & BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2347		printk(KERN_INFO
2348		       "bh_end_io(error=%d) for %c @%llu (%s/%llu/%d)\n",
2349		       iodone_w_error,
2350		       btrfsic_get_block_type(dev_state->state, block),
2351		       (unsigned long long)block->logical_bytenr,
2352		       block->dev_state->name,
2353		       (unsigned long long)block->dev_bytenr,
2354		       block->mirror_num);
2355
2356	block->iodone_w_error = iodone_w_error;
2357	if (block->submit_bio_bh_rw & REQ_FLUSH) {
2358		dev_state->last_flush_gen++;
2359		if ((dev_state->state->print_mask &
2360		     BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2361			printk(KERN_INFO
2362			       "bh_end_io() new %s flush_gen=%llu\n",
2363			       dev_state->name,
2364			       (unsigned long long)dev_state->last_flush_gen);
2365	}
2366	if (block->submit_bio_bh_rw & REQ_FUA)
2367		block->flush_gen = 0; /* FUA completed means block is on disk */
2368
2369	bh->b_private = block->orig_bio_bh_private;
2370	bh->b_end_io = block->orig_bio_bh_end_io.bh;
2371	block->is_iodone = 1; /* for FLUSH, this releases the block */
2372	bh->b_end_io(bh, uptodate);
2373}
2374
2375static int btrfsic_process_written_superblock(
2376		struct btrfsic_state *state,
2377		struct btrfsic_block *const superblock,
2378		struct btrfs_super_block *const super_hdr)
2379{
2380	int pass;
2381
2382	superblock->generation = btrfs_super_generation(super_hdr);
2383	if (!(superblock->generation > state->max_superblock_generation ||
2384	      0 == state->max_superblock_generation)) {
2385		if (state->print_mask & BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE)
2386			printk(KERN_INFO
2387			       "btrfsic: superblock @%llu (%s/%llu/%d)"
2388			       " with old gen %llu <= %llu\n",
2389			       (unsigned long long)superblock->logical_bytenr,
2390			       superblock->dev_state->name,
2391			       (unsigned long long)superblock->dev_bytenr,
2392			       superblock->mirror_num,
2393			       (unsigned long long)
2394			       btrfs_super_generation(super_hdr),
2395			       (unsigned long long)
2396			       state->max_superblock_generation);
2397	} else {
2398		if (state->print_mask & BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE)
2399			printk(KERN_INFO
2400			       "btrfsic: got new superblock @%llu (%s/%llu/%d)"
2401			       " with new gen %llu > %llu\n",
2402			       (unsigned long long)superblock->logical_bytenr,
2403			       superblock->dev_state->name,
2404			       (unsigned long long)superblock->dev_bytenr,
2405			       superblock->mirror_num,
2406			       (unsigned long long)
2407			       btrfs_super_generation(super_hdr),
2408			       (unsigned long long)
2409			       state->max_superblock_generation);
2410
2411		state->max_superblock_generation =
2412		    btrfs_super_generation(super_hdr);
2413		state->latest_superblock = superblock;
2414	}
2415
2416	for (pass = 0; pass < 3; pass++) {
2417		int ret;
2418		u64 next_bytenr;
2419		struct btrfsic_block *next_block;
2420		struct btrfsic_block_data_ctx tmp_next_block_ctx;
2421		struct btrfsic_block_link *l;
2422		int num_copies;
2423		int mirror_num;
2424		const char *additional_string = NULL;
2425		struct btrfs_disk_key tmp_disk_key;
2426
2427		tmp_disk_key.type = BTRFS_ROOT_ITEM_KEY;
2428		tmp_disk_key.offset = 0;
2429
2430		switch (pass) {
2431		case 0:
2432			tmp_disk_key.objectid =
2433			    cpu_to_le64(BTRFS_ROOT_TREE_OBJECTID);
2434			additional_string = "root ";
2435			next_bytenr = btrfs_super_root(super_hdr);
2436			if (state->print_mask &
2437			    BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
2438				printk(KERN_INFO "root@%llu\n",
2439				       (unsigned long long)next_bytenr);
2440			break;
2441		case 1:
2442			tmp_disk_key.objectid =
2443			    cpu_to_le64(BTRFS_CHUNK_TREE_OBJECTID);
2444			additional_string = "chunk ";
2445			next_bytenr = btrfs_super_chunk_root(super_hdr);
2446			if (state->print_mask &
2447			    BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
2448				printk(KERN_INFO "chunk@%llu\n",
2449				       (unsigned long long)next_bytenr);
2450			break;
2451		case 2:
2452			tmp_disk_key.objectid =
2453			    cpu_to_le64(BTRFS_TREE_LOG_OBJECTID);
2454			additional_string = "log ";
2455			next_bytenr = btrfs_super_log_root(super_hdr);
2456			if (0 == next_bytenr)
2457				continue;
2458			if (state->print_mask &
2459			    BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
2460				printk(KERN_INFO "log@%llu\n",
2461				       (unsigned long long)next_bytenr);
2462			break;
2463		}
2464
2465		num_copies =
2466		    btrfs_num_copies(state->root->fs_info,
2467				     next_bytenr, BTRFS_SUPER_INFO_SIZE);
2468		if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
2469			printk(KERN_INFO "num_copies(log_bytenr=%llu) = %d\n",
2470			       (unsigned long long)next_bytenr, num_copies);
2471		for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
2472			int was_created;
2473
2474			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2475				printk(KERN_INFO
2476				       "btrfsic_process_written_superblock("
2477				       "mirror_num=%d)\n", mirror_num);
2478			ret = btrfsic_map_block(state, next_bytenr,
2479						BTRFS_SUPER_INFO_SIZE,
2480						&tmp_next_block_ctx,
2481						mirror_num);
2482			if (ret) {
2483				printk(KERN_INFO
2484				       "btrfsic: btrfsic_map_block(@%llu,"
2485				       " mirror=%d) failed!\n",
2486				       (unsigned long long)next_bytenr,
2487				       mirror_num);
2488				return -1;
2489			}
2490
2491			next_block = btrfsic_block_lookup_or_add(
2492					state,
2493					&tmp_next_block_ctx,
2494					additional_string,
2495					1, 0, 1,
2496					mirror_num,
2497					&was_created);
2498			if (NULL == next_block) {
2499				printk(KERN_INFO
2500				       "btrfsic: error, kmalloc failed!\n");
2501				btrfsic_release_block_ctx(&tmp_next_block_ctx);
2502				return -1;
2503			}
2504
2505			next_block->disk_key = tmp_disk_key;
2506			if (was_created)
2507				next_block->generation =
2508				    BTRFSIC_GENERATION_UNKNOWN;
2509			l = btrfsic_block_link_lookup_or_add(
2510					state,
2511					&tmp_next_block_ctx,
2512					next_block,
2513					superblock,
2514					BTRFSIC_GENERATION_UNKNOWN);
2515			btrfsic_release_block_ctx(&tmp_next_block_ctx);
2516			if (NULL == l)
2517				return -1;
2518		}
2519	}
2520
2521	if (-1 == btrfsic_check_all_ref_blocks(state, superblock, 0)) {
2522		WARN_ON(1);
2523		btrfsic_dump_tree(state);
2524	}
2525
2526	return 0;
2527}
2528
2529static int btrfsic_check_all_ref_blocks(struct btrfsic_state *state,
2530					struct btrfsic_block *const block,
2531					int recursion_level)
2532{
2533	struct list_head *elem_ref_to;
2534	int ret = 0;
2535
2536	if (recursion_level >= 3 + BTRFS_MAX_LEVEL) {
2537		/*
2538		 * Note that this situation can happen and does not
2539		 * indicate an error in regular cases. It happens
2540		 * when disk blocks are freed and later reused.
2541		 * The check-integrity module is not aware of any
2542		 * block free operations, it just recognizes block
2543		 * write operations. Therefore it keeps the linkage
2544		 * information for a block until a block is
2545		 * rewritten. This can temporarily cause incorrect
2546		 * and even circular linkage informations. This
2547		 * causes no harm unless such blocks are referenced
2548		 * by the most recent super block.
2549		 */
2550		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2551			printk(KERN_INFO
2552			       "btrfsic: abort cyclic linkage (case 1).\n");
2553
2554		return ret;
2555	}
2556
2557	/*
2558	 * This algorithm is recursive because the amount of used stack
2559	 * space is very small and the max recursion depth is limited.
2560	 */
2561	list_for_each(elem_ref_to, &block->ref_to_list) {
2562		const struct btrfsic_block_link *const l =
2563		    list_entry(elem_ref_to, struct btrfsic_block_link,
2564			       node_ref_to);
2565
2566		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2567			printk(KERN_INFO
2568			       "rl=%d, %c @%llu (%s/%llu/%d)"
2569			       " %u* refers to %c @%llu (%s/%llu/%d)\n",
2570			       recursion_level,
2571			       btrfsic_get_block_type(state, block),
2572			       (unsigned long long)block->logical_bytenr,
2573			       block->dev_state->name,
2574			       (unsigned long long)block->dev_bytenr,
2575			       block->mirror_num,
2576			       l->ref_cnt,
2577			       btrfsic_get_block_type(state, l->block_ref_to),
2578			       (unsigned long long)
2579			       l->block_ref_to->logical_bytenr,
2580			       l->block_ref_to->dev_state->name,
2581			       (unsigned long long)l->block_ref_to->dev_bytenr,
2582			       l->block_ref_to->mirror_num);
2583		if (l->block_ref_to->never_written) {
2584			printk(KERN_INFO "btrfs: attempt to write superblock"
2585			       " which references block %c @%llu (%s/%llu/%d)"
2586			       " which is never written!\n",
2587			       btrfsic_get_block_type(state, l->block_ref_to),
2588			       (unsigned long long)
2589			       l->block_ref_to->logical_bytenr,
2590			       l->block_ref_to->dev_state->name,
2591			       (unsigned long long)l->block_ref_to->dev_bytenr,
2592			       l->block_ref_to->mirror_num);
2593			ret = -1;
2594		} else if (!l->block_ref_to->is_iodone) {
2595			printk(KERN_INFO "btrfs: attempt to write superblock"
2596			       " which references block %c @%llu (%s/%llu/%d)"
2597			       " which is not yet iodone!\n",
2598			       btrfsic_get_block_type(state, l->block_ref_to),
2599			       (unsigned long long)
2600			       l->block_ref_to->logical_bytenr,
2601			       l->block_ref_to->dev_state->name,
2602			       (unsigned long long)l->block_ref_to->dev_bytenr,
2603			       l->block_ref_to->mirror_num);
2604			ret = -1;
2605		} else if (l->block_ref_to->iodone_w_error) {
2606			printk(KERN_INFO "btrfs: attempt to write superblock"
2607			       " which references block %c @%llu (%s/%llu/%d)"
2608			       " which has write error!\n",
2609			       btrfsic_get_block_type(state, l->block_ref_to),
2610			       (unsigned long long)
2611			       l->block_ref_to->logical_bytenr,
2612			       l->block_ref_to->dev_state->name,
2613			       (unsigned long long)l->block_ref_to->dev_bytenr,
2614			       l->block_ref_to->mirror_num);
2615			ret = -1;
2616		} else if (l->parent_generation !=
2617			   l->block_ref_to->generation &&
2618			   BTRFSIC_GENERATION_UNKNOWN !=
2619			   l->parent_generation &&
2620			   BTRFSIC_GENERATION_UNKNOWN !=
2621			   l->block_ref_to->generation) {
2622			printk(KERN_INFO "btrfs: attempt to write superblock"
2623			       " which references block %c @%llu (%s/%llu/%d)"
2624			       " with generation %llu !="
2625			       " parent generation %llu!\n",
2626			       btrfsic_get_block_type(state, l->block_ref_to),
2627			       (unsigned long long)
2628			       l->block_ref_to->logical_bytenr,
2629			       l->block_ref_to->dev_state->name,
2630			       (unsigned long long)l->block_ref_to->dev_bytenr,
2631			       l->block_ref_to->mirror_num,
2632			       (unsigned long long)l->block_ref_to->generation,
2633			       (unsigned long long)l->parent_generation);
2634			ret = -1;
2635		} else if (l->block_ref_to->flush_gen >
2636			   l->block_ref_to->dev_state->last_flush_gen) {
2637			printk(KERN_INFO "btrfs: attempt to write superblock"
2638			       " which references block %c @%llu (%s/%llu/%d)"
2639			       " which is not flushed out of disk's write cache"
2640			       " (block flush_gen=%llu,"
2641			       " dev->flush_gen=%llu)!\n",
2642			       btrfsic_get_block_type(state, l->block_ref_to),
2643			       (unsigned long long)
2644			       l->block_ref_to->logical_bytenr,
2645			       l->block_ref_to->dev_state->name,
2646			       (unsigned long long)l->block_ref_to->dev_bytenr,
2647			       l->block_ref_to->mirror_num,
2648			       (unsigned long long)block->flush_gen,
2649			       (unsigned long long)
2650			       l->block_ref_to->dev_state->last_flush_gen);
2651			ret = -1;
2652		} else if (-1 == btrfsic_check_all_ref_blocks(state,
2653							      l->block_ref_to,
2654							      recursion_level +
2655							      1)) {
2656			ret = -1;
2657		}
2658	}
2659
2660	return ret;
2661}
2662
2663static int btrfsic_is_block_ref_by_superblock(
2664		const struct btrfsic_state *state,
2665		const struct btrfsic_block *block,
2666		int recursion_level)
2667{
2668	struct list_head *elem_ref_from;
2669
2670	if (recursion_level >= 3 + BTRFS_MAX_LEVEL) {
2671		/* refer to comment at "abort cyclic linkage (case 1)" */
2672		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2673			printk(KERN_INFO
2674			       "btrfsic: abort cyclic linkage (case 2).\n");
2675
2676		return 0;
2677	}
2678
2679	/*
2680	 * This algorithm is recursive because the amount of used stack space
2681	 * is very small and the max recursion depth is limited.
2682	 */
2683	list_for_each(elem_ref_from, &block->ref_from_list) {
2684		const struct btrfsic_block_link *const l =
2685		    list_entry(elem_ref_from, struct btrfsic_block_link,
2686			       node_ref_from);
2687
2688		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2689			printk(KERN_INFO
2690			       "rl=%d, %c @%llu (%s/%llu/%d)"
2691			       " is ref %u* from %c @%llu (%s/%llu/%d)\n",
2692			       recursion_level,
2693			       btrfsic_get_block_type(state, block),
2694			       (unsigned long long)block->logical_bytenr,
2695			       block->dev_state->name,
2696			       (unsigned long long)block->dev_bytenr,
2697			       block->mirror_num,
2698			       l->ref_cnt,
2699			       btrfsic_get_block_type(state, l->block_ref_from),
2700			       (unsigned long long)
2701			       l->block_ref_from->logical_bytenr,
2702			       l->block_ref_from->dev_state->name,
2703			       (unsigned long long)
2704			       l->block_ref_from->dev_bytenr,
2705			       l->block_ref_from->mirror_num);
2706		if (l->block_ref_from->is_superblock &&
2707		    state->latest_superblock->dev_bytenr ==
2708		    l->block_ref_from->dev_bytenr &&
2709		    state->latest_superblock->dev_state->bdev ==
2710		    l->block_ref_from->dev_state->bdev)
2711			return 1;
2712		else if (btrfsic_is_block_ref_by_superblock(state,
2713							    l->block_ref_from,
2714							    recursion_level +
2715							    1))
2716			return 1;
2717	}
2718
2719	return 0;
2720}
2721
2722static void btrfsic_print_add_link(const struct btrfsic_state *state,
2723				   const struct btrfsic_block_link *l)
2724{
2725	printk(KERN_INFO
2726	       "Add %u* link from %c @%llu (%s/%llu/%d)"
2727	       " to %c @%llu (%s/%llu/%d).\n",
2728	       l->ref_cnt,
2729	       btrfsic_get_block_type(state, l->block_ref_from),
2730	       (unsigned long long)l->block_ref_from->logical_bytenr,
2731	       l->block_ref_from->dev_state->name,
2732	       (unsigned long long)l->block_ref_from->dev_bytenr,
2733	       l->block_ref_from->mirror_num,
2734	       btrfsic_get_block_type(state, l->block_ref_to),
2735	       (unsigned long long)l->block_ref_to->logical_bytenr,
2736	       l->block_ref_to->dev_state->name,
2737	       (unsigned long long)l->block_ref_to->dev_bytenr,
2738	       l->block_ref_to->mirror_num);
2739}
2740
2741static void btrfsic_print_rem_link(const struct btrfsic_state *state,
2742				   const struct btrfsic_block_link *l)
2743{
2744	printk(KERN_INFO
2745	       "Rem %u* link from %c @%llu (%s/%llu/%d)"
2746	       " to %c @%llu (%s/%llu/%d).\n",
2747	       l->ref_cnt,
2748	       btrfsic_get_block_type(state, l->block_ref_from),
2749	       (unsigned long long)l->block_ref_from->logical_bytenr,
2750	       l->block_ref_from->dev_state->name,
2751	       (unsigned long long)l->block_ref_from->dev_bytenr,
2752	       l->block_ref_from->mirror_num,
2753	       btrfsic_get_block_type(state, l->block_ref_to),
2754	       (unsigned long long)l->block_ref_to->logical_bytenr,
2755	       l->block_ref_to->dev_state->name,
2756	       (unsigned long long)l->block_ref_to->dev_bytenr,
2757	       l->block_ref_to->mirror_num);
2758}
2759
2760static char btrfsic_get_block_type(const struct btrfsic_state *state,
2761				   const struct btrfsic_block *block)
2762{
2763	if (block->is_superblock &&
2764	    state->latest_superblock->dev_bytenr == block->dev_bytenr &&
2765	    state->latest_superblock->dev_state->bdev == block->dev_state->bdev)
2766		return 'S';
2767	else if (block->is_superblock)
2768		return 's';
2769	else if (block->is_metadata)
2770		return 'M';
2771	else
2772		return 'D';
2773}
2774
2775static void btrfsic_dump_tree(const struct btrfsic_state *state)
2776{
2777	btrfsic_dump_tree_sub(state, state->latest_superblock, 0);
2778}
2779
2780static void btrfsic_dump_tree_sub(const struct btrfsic_state *state,
2781				  const struct btrfsic_block *block,
2782				  int indent_level)
2783{
2784	struct list_head *elem_ref_to;
2785	int indent_add;
2786	static char buf[80];
2787	int cursor_position;
2788
2789	/*
2790	 * Should better fill an on-stack buffer with a complete line and
2791	 * dump it at once when it is time to print a newline character.
2792	 */
2793
2794	/*
2795	 * This algorithm is recursive because the amount of used stack space
2796	 * is very small and the max recursion depth is limited.
2797	 */
2798	indent_add = sprintf(buf, "%c-%llu(%s/%llu/%d)",
2799			     btrfsic_get_block_type(state, block),
2800			     (unsigned long long)block->logical_bytenr,
2801			     block->dev_state->name,
2802			     (unsigned long long)block->dev_bytenr,
2803			     block->mirror_num);
2804	if (indent_level + indent_add > BTRFSIC_TREE_DUMP_MAX_INDENT_LEVEL) {
2805		printk("[...]\n");
2806		return;
2807	}
2808	printk(buf);
2809	indent_level += indent_add;
2810	if (list_empty(&block->ref_to_list)) {
2811		printk("\n");
2812		return;
2813	}
2814	if (block->mirror_num > 1 &&
2815	    !(state->print_mask & BTRFSIC_PRINT_MASK_TREE_WITH_ALL_MIRRORS)) {
2816		printk(" [...]\n");
2817		return;
2818	}
2819
2820	cursor_position = indent_level;
2821	list_for_each(elem_ref_to, &block->ref_to_list) {
2822		const struct btrfsic_block_link *const l =
2823		    list_entry(elem_ref_to, struct btrfsic_block_link,
2824			       node_ref_to);
2825
2826		while (cursor_position < indent_level) {
2827			printk(" ");
2828			cursor_position++;
2829		}
2830		if (l->ref_cnt > 1)
2831			indent_add = sprintf(buf, " %d*--> ", l->ref_cnt);
2832		else
2833			indent_add = sprintf(buf, " --> ");
2834		if (indent_level + indent_add >
2835		    BTRFSIC_TREE_DUMP_MAX_INDENT_LEVEL) {
2836			printk("[...]\n");
2837			cursor_position = 0;
2838			continue;
2839		}
2840
2841		printk(buf);
2842
2843		btrfsic_dump_tree_sub(state, l->block_ref_to,
2844				      indent_level + indent_add);
2845		cursor_position = 0;
2846	}
2847}
2848
2849static struct btrfsic_block_link *btrfsic_block_link_lookup_or_add(
2850		struct btrfsic_state *state,
2851		struct btrfsic_block_data_ctx *next_block_ctx,
2852		struct btrfsic_block *next_block,
2853		struct btrfsic_block *from_block,
2854		u64 parent_generation)
2855{
2856	struct btrfsic_block_link *l;
2857
2858	l = btrfsic_block_link_hashtable_lookup(next_block_ctx->dev->bdev,
2859						next_block_ctx->dev_bytenr,
2860						from_block->dev_state->bdev,
2861						from_block->dev_bytenr,
2862						&state->block_link_hashtable);
2863	if (NULL == l) {
2864		l = btrfsic_block_link_alloc();
2865		if (NULL == l) {
2866			printk(KERN_INFO
2867			       "btrfsic: error, kmalloc" " failed!\n");
2868			return NULL;
2869		}
2870
2871		l->block_ref_to = next_block;
2872		l->block_ref_from = from_block;
2873		l->ref_cnt = 1;
2874		l->parent_generation = parent_generation;
2875
2876		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2877			btrfsic_print_add_link(state, l);
2878
2879		list_add(&l->node_ref_to, &from_block->ref_to_list);
2880		list_add(&l->node_ref_from, &next_block->ref_from_list);
2881
2882		btrfsic_block_link_hashtable_add(l,
2883						 &state->block_link_hashtable);
2884	} else {
2885		l->ref_cnt++;
2886		l->parent_generation = parent_generation;
2887		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2888			btrfsic_print_add_link(state, l);
2889	}
2890
2891	return l;
2892}
2893
2894static struct btrfsic_block *btrfsic_block_lookup_or_add(
2895		struct btrfsic_state *state,
2896		struct btrfsic_block_data_ctx *block_ctx,
2897		const char *additional_string,
2898		int is_metadata,
2899		int is_iodone,
2900		int never_written,
2901		int mirror_num,
2902		int *was_created)
2903{
2904	struct btrfsic_block *block;
2905
2906	block = btrfsic_block_hashtable_lookup(block_ctx->dev->bdev,
2907					       block_ctx->dev_bytenr,
2908					       &state->block_hashtable);
2909	if (NULL == block) {
2910		struct btrfsic_dev_state *dev_state;
2911
2912		block = btrfsic_block_alloc();
2913		if (NULL == block) {
2914			printk(KERN_INFO "btrfsic: error, kmalloc failed!\n");
2915			return NULL;
2916		}
2917		dev_state = btrfsic_dev_state_lookup(block_ctx->dev->bdev);
2918		if (NULL == dev_state) {
2919			printk(KERN_INFO
2920			       "btrfsic: error, lookup dev_state failed!\n");
2921			btrfsic_block_free(block);
2922			return NULL;
2923		}
2924		block->dev_state = dev_state;
2925		block->dev_bytenr = block_ctx->dev_bytenr;
2926		block->logical_bytenr = block_ctx->start;
2927		block->is_metadata = is_metadata;
2928		block->is_iodone = is_iodone;
2929		block->never_written = never_written;
2930		block->mirror_num = mirror_num;
2931		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2932			printk(KERN_INFO
2933			       "New %s%c-block @%llu (%s/%llu/%d)\n",
2934			       additional_string,
2935			       btrfsic_get_block_type(state, block),
2936			       (unsigned long long)block->logical_bytenr,
2937			       dev_state->name,
2938			       (unsigned long long)block->dev_bytenr,
2939			       mirror_num);
2940		list_add(&block->all_blocks_node, &state->all_blocks_list);
2941		btrfsic_block_hashtable_add(block, &state->block_hashtable);
2942		if (NULL != was_created)
2943			*was_created = 1;
2944	} else {
2945		if (NULL != was_created)
2946			*was_created = 0;
2947	}
2948
2949	return block;
2950}
2951
2952static void btrfsic_cmp_log_and_dev_bytenr(struct btrfsic_state *state,
2953					   u64 bytenr,
2954					   struct btrfsic_dev_state *dev_state,
2955					   u64 dev_bytenr)
2956{
2957	int num_copies;
2958	int mirror_num;
2959	int ret;
2960	struct btrfsic_block_data_ctx block_ctx;
2961	int match = 0;
2962
2963	num_copies = btrfs_num_copies(state->root->fs_info,
2964				      bytenr, state->metablock_size);
2965
2966	for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
2967		ret = btrfsic_map_block(state, bytenr, state->metablock_size,
2968					&block_ctx, mirror_num);
2969		if (ret) {
2970			printk(KERN_INFO "btrfsic:"
2971			       " btrfsic_map_block(logical @%llu,"
2972			       " mirror %d) failed!\n",
2973			       (unsigned long long)bytenr, mirror_num);
2974			continue;
2975		}
2976
2977		if (dev_state->bdev == block_ctx.dev->bdev &&
2978		    dev_bytenr == block_ctx.dev_bytenr) {
2979			match++;
2980			btrfsic_release_block_ctx(&block_ctx);
2981			break;
2982		}
2983		btrfsic_release_block_ctx(&block_ctx);
2984	}
2985
2986	if (!match) {
2987		printk(KERN_INFO "btrfs: attempt to write M-block which contains logical bytenr that doesn't map to dev+physical bytenr of submit_bio,"
2988		       " buffer->log_bytenr=%llu, submit_bio(bdev=%s,"
2989		       " phys_bytenr=%llu)!\n",
2990		       (unsigned long long)bytenr, dev_state->name,
2991		       (unsigned long long)dev_bytenr);
2992		for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
2993			ret = btrfsic_map_block(state, bytenr,
2994						state->metablock_size,
2995						&block_ctx, mirror_num);
2996			if (ret)
2997				continue;
2998
2999			printk(KERN_INFO "Read logical bytenr @%llu maps to"
3000			       " (%s/%llu/%d)\n",
3001			       (unsigned long long)bytenr,
3002			       block_ctx.dev->name,
3003			       (unsigned long long)block_ctx.dev_bytenr,
3004			       mirror_num);
3005		}
3006		WARN_ON(1);
3007	}
3008}
3009
3010static struct btrfsic_dev_state *btrfsic_dev_state_lookup(
3011		struct block_device *bdev)
3012{
3013	struct btrfsic_dev_state *ds;
3014
3015	ds = btrfsic_dev_state_hashtable_lookup(bdev,
3016						&btrfsic_dev_state_hashtable);
3017	return ds;
3018}
3019
3020int btrfsic_submit_bh(int rw, struct buffer_head *bh)
3021{
3022	struct btrfsic_dev_state *dev_state;
3023
3024	if (!btrfsic_is_initialized)
3025		return submit_bh(rw, bh);
3026
3027	mutex_lock(&btrfsic_mutex);
3028	/* since btrfsic_submit_bh() might also be called before
3029	 * btrfsic_mount(), this might return NULL */
3030	dev_state = btrfsic_dev_state_lookup(bh->b_bdev);
3031
3032	/* Only called to write the superblock (incl. FLUSH/FUA) */
3033	if (NULL != dev_state &&
3034	    (rw & WRITE) && bh->b_size > 0) {
3035		u64 dev_bytenr;
3036
3037		dev_bytenr = 4096 * bh->b_blocknr;
3038		if (dev_state->state->print_mask &
3039		    BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
3040			printk(KERN_INFO
3041			       "submit_bh(rw=0x%x, blocknr=%lu (bytenr %llu),"
3042			       " size=%lu, data=%p, bdev=%p)\n",
3043			       rw, (unsigned long)bh->b_blocknr,
3044			       (unsigned long long)dev_bytenr,
3045			       (unsigned long)bh->b_size, bh->b_data,
3046			       bh->b_bdev);
3047		btrfsic_process_written_block(dev_state, dev_bytenr,
3048					      &bh->b_data, 1, NULL,
3049					      NULL, bh, rw);
3050	} else if (NULL != dev_state && (rw & REQ_FLUSH)) {
3051		if (dev_state->state->print_mask &
3052		    BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
3053			printk(KERN_INFO
3054			       "submit_bh(rw=0x%x FLUSH, bdev=%p)\n",
3055			       rw, bh->b_bdev);
3056		if (!dev_state->dummy_block_for_bio_bh_flush.is_iodone) {
3057			if ((dev_state->state->print_mask &
3058			     (BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH |
3059			      BTRFSIC_PRINT_MASK_VERBOSE)))
3060				printk(KERN_INFO
3061				       "btrfsic_submit_bh(%s) with FLUSH"
3062				       " but dummy block already in use"
3063				       " (ignored)!\n",
3064				       dev_state->name);
3065		} else {
3066			struct btrfsic_block *const block =
3067				&dev_state->dummy_block_for_bio_bh_flush;
3068
3069			block->is_iodone = 0;
3070			block->never_written = 0;
3071			block->iodone_w_error = 0;
3072			block->flush_gen = dev_state->last_flush_gen + 1;
3073			block->submit_bio_bh_rw = rw;
3074			block->orig_bio_bh_private = bh->b_private;
3075			block->orig_bio_bh_end_io.bh = bh->b_end_io;
3076			block->next_in_same_bio = NULL;
3077			bh->b_private = block;
3078			bh->b_end_io = btrfsic_bh_end_io;
3079		}
3080	}
3081	mutex_unlock(&btrfsic_mutex);
3082	return submit_bh(rw, bh);
3083}
3084
3085void btrfsic_submit_bio(int rw, struct bio *bio)
3086{
3087	struct btrfsic_dev_state *dev_state;
3088
3089	if (!btrfsic_is_initialized) {
3090		submit_bio(rw, bio);
3091		return;
3092	}
3093
3094	mutex_lock(&btrfsic_mutex);
3095	/* since btrfsic_submit_bio() is also called before
3096	 * btrfsic_mount(), this might return NULL */
3097	dev_state = btrfsic_dev_state_lookup(bio->bi_bdev);
3098	if (NULL != dev_state &&
3099	    (rw & WRITE) && NULL != bio->bi_io_vec) {
3100		unsigned int i;
3101		u64 dev_bytenr;
3102		int bio_is_patched;
3103		char **mapped_datav;
3104
3105		dev_bytenr = 512 * bio->bi_sector;
3106		bio_is_patched = 0;
3107		if (dev_state->state->print_mask &
3108		    BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
3109			printk(KERN_INFO
3110			       "submit_bio(rw=0x%x, bi_vcnt=%u,"
3111			       " bi_sector=%lu (bytenr %llu), bi_bdev=%p)\n",
3112			       rw, bio->bi_vcnt, (unsigned long)bio->bi_sector,
3113			       (unsigned long long)dev_bytenr,
3114			       bio->bi_bdev);
3115
3116		mapped_datav = kmalloc(sizeof(*mapped_datav) * bio->bi_vcnt,
3117				       GFP_NOFS);
3118		if (!mapped_datav)
3119			goto leave;
3120		for (i = 0; i < bio->bi_vcnt; i++) {
3121			BUG_ON(bio->bi_io_vec[i].bv_len != PAGE_CACHE_SIZE);
3122			mapped_datav[i] = kmap(bio->bi_io_vec[i].bv_page);
3123			if (!mapped_datav[i]) {
3124				while (i > 0) {
3125					i--;
3126					kunmap(bio->bi_io_vec[i].bv_page);
3127				}
3128				kfree(mapped_datav);
3129				goto leave;
3130			}
3131			if ((BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH |
3132			     BTRFSIC_PRINT_MASK_VERBOSE) ==
3133			    (dev_state->state->print_mask &
3134			     (BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH |
3135			      BTRFSIC_PRINT_MASK_VERBOSE)))
3136				printk(KERN_INFO
3137				       "#%u: page=%p, len=%u, offset=%u\n",
3138				       i, bio->bi_io_vec[i].bv_page,
3139				       bio->bi_io_vec[i].bv_len,
3140				       bio->bi_io_vec[i].bv_offset);
3141		}
3142		btrfsic_process_written_block(dev_state, dev_bytenr,
3143					      mapped_datav, bio->bi_vcnt,
3144					      bio, &bio_is_patched,
3145					      NULL, rw);
3146		while (i > 0) {
3147			i--;
3148			kunmap(bio->bi_io_vec[i].bv_page);
3149		}
3150		kfree(mapped_datav);
3151	} else if (NULL != dev_state && (rw & REQ_FLUSH)) {
3152		if (dev_state->state->print_mask &
3153		    BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
3154			printk(KERN_INFO
3155			       "submit_bio(rw=0x%x FLUSH, bdev=%p)\n",
3156			       rw, bio->bi_bdev);
3157		if (!dev_state->dummy_block_for_bio_bh_flush.is_iodone) {
3158			if ((dev_state->state->print_mask &
3159			     (BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH |
3160			      BTRFSIC_PRINT_MASK_VERBOSE)))
3161				printk(KERN_INFO
3162				       "btrfsic_submit_bio(%s) with FLUSH"
3163				       " but dummy block already in use"
3164				       " (ignored)!\n",
3165				       dev_state->name);
3166		} else {
3167			struct btrfsic_block *const block =
3168				&dev_state->dummy_block_for_bio_bh_flush;
3169
3170			block->is_iodone = 0;
3171			block->never_written = 0;
3172			block->iodone_w_error = 0;
3173			block->flush_gen = dev_state->last_flush_gen + 1;
3174			block->submit_bio_bh_rw = rw;
3175			block->orig_bio_bh_private = bio->bi_private;
3176			block->orig_bio_bh_end_io.bio = bio->bi_end_io;
3177			block->next_in_same_bio = NULL;
3178			bio->bi_private = block;
3179			bio->bi_end_io = btrfsic_bio_end_io;
3180		}
3181	}
3182leave:
3183	mutex_unlock(&btrfsic_mutex);
3184
3185	submit_bio(rw, bio);
3186}
3187
3188int btrfsic_mount(struct btrfs_root *root,
3189		  struct btrfs_fs_devices *fs_devices,
3190		  int including_extent_data, u32 print_mask)
3191{
3192	int ret;
3193	struct btrfsic_state *state;
3194	struct list_head *dev_head = &fs_devices->devices;
3195	struct btrfs_device *device;
3196
3197	if (root->nodesize != root->leafsize) {
3198		printk(KERN_INFO
3199		       "btrfsic: cannot handle nodesize %d != leafsize %d!\n",
3200		       root->nodesize, root->leafsize);
3201		return -1;
3202	}
3203	if (root->nodesize & ((u64)PAGE_CACHE_SIZE - 1)) {
3204		printk(KERN_INFO
3205		       "btrfsic: cannot handle nodesize %d not being a multiple of PAGE_CACHE_SIZE %ld!\n",
3206		       root->nodesize, (unsigned long)PAGE_CACHE_SIZE);
3207		return -1;
3208	}
3209	if (root->leafsize & ((u64)PAGE_CACHE_SIZE - 1)) {
3210		printk(KERN_INFO
3211		       "btrfsic: cannot handle leafsize %d not being a multiple of PAGE_CACHE_SIZE %ld!\n",
3212		       root->leafsize, (unsigned long)PAGE_CACHE_SIZE);
3213		return -1;
3214	}
3215	if (root->sectorsize & ((u64)PAGE_CACHE_SIZE - 1)) {
3216		printk(KERN_INFO
3217		       "btrfsic: cannot handle sectorsize %d not being a multiple of PAGE_CACHE_SIZE %ld!\n",
3218		       root->sectorsize, (unsigned long)PAGE_CACHE_SIZE);
3219		return -1;
3220	}
3221	state = kzalloc(sizeof(*state), GFP_NOFS);
3222	if (NULL == state) {
3223		printk(KERN_INFO "btrfs check-integrity: kmalloc() failed!\n");
3224		return -1;
3225	}
3226
3227	if (!btrfsic_is_initialized) {
3228		mutex_init(&btrfsic_mutex);
3229		btrfsic_dev_state_hashtable_init(&btrfsic_dev_state_hashtable);
3230		btrfsic_is_initialized = 1;
3231	}
3232	mutex_lock(&btrfsic_mutex);
3233	state->root = root;
3234	state->print_mask = print_mask;
3235	state->include_extent_data = including_extent_data;
3236	state->csum_size = 0;
3237	state->metablock_size = root->nodesize;
3238	state->datablock_size = root->sectorsize;
3239	INIT_LIST_HEAD(&state->all_blocks_list);
3240	btrfsic_block_hashtable_init(&state->block_hashtable);
3241	btrfsic_block_link_hashtable_init(&state->block_link_hashtable);
3242	state->max_superblock_generation = 0;
3243	state->latest_superblock = NULL;
3244
3245	list_for_each_entry(device, dev_head, dev_list) {
3246		struct btrfsic_dev_state *ds;
3247		char *p;
3248
3249		if (!device->bdev || !device->name)
3250			continue;
3251
3252		ds = btrfsic_dev_state_alloc();
3253		if (NULL == ds) {
3254			printk(KERN_INFO
3255			       "btrfs check-integrity: kmalloc() failed!\n");
3256			mutex_unlock(&btrfsic_mutex);
3257			return -1;
3258		}
3259		ds->bdev = device->bdev;
3260		ds->state = state;
3261		bdevname(ds->bdev, ds->name);
3262		ds->name[BDEVNAME_SIZE - 1] = '\0';
3263		for (p = ds->name; *p != '\0'; p++);
3264		while (p > ds->name && *p != '/')
3265			p--;
3266		if (*p == '/')
3267			p++;
3268		strlcpy(ds->name, p, sizeof(ds->name));
3269		btrfsic_dev_state_hashtable_add(ds,
3270						&btrfsic_dev_state_hashtable);
3271	}
3272
3273	ret = btrfsic_process_superblock(state, fs_devices);
3274	if (0 != ret) {
3275		mutex_unlock(&btrfsic_mutex);
3276		btrfsic_unmount(root, fs_devices);
3277		return ret;
3278	}
3279
3280	if (state->print_mask & BTRFSIC_PRINT_MASK_INITIAL_DATABASE)
3281		btrfsic_dump_database(state);
3282	if (state->print_mask & BTRFSIC_PRINT_MASK_INITIAL_TREE)
3283		btrfsic_dump_tree(state);
3284
3285	mutex_unlock(&btrfsic_mutex);
3286	return 0;
3287}
3288
3289void btrfsic_unmount(struct btrfs_root *root,
3290		     struct btrfs_fs_devices *fs_devices)
3291{
3292	struct list_head *elem_all;
3293	struct list_head *tmp_all;
3294	struct btrfsic_state *state;
3295	struct list_head *dev_head = &fs_devices->devices;
3296	struct btrfs_device *device;
3297
3298	if (!btrfsic_is_initialized)
3299		return;
3300
3301	mutex_lock(&btrfsic_mutex);
3302
3303	state = NULL;
3304	list_for_each_entry(device, dev_head, dev_list) {
3305		struct btrfsic_dev_state *ds;
3306
3307		if (!device->bdev || !device->name)
3308			continue;
3309
3310		ds = btrfsic_dev_state_hashtable_lookup(
3311				device->bdev,
3312				&btrfsic_dev_state_hashtable);
3313		if (NULL != ds) {
3314			state = ds->state;
3315			btrfsic_dev_state_hashtable_remove(ds);
3316			btrfsic_dev_state_free(ds);
3317		}
3318	}
3319
3320	if (NULL == state) {
3321		printk(KERN_INFO
3322		       "btrfsic: error, cannot find state information"
3323		       " on umount!\n");
3324		mutex_unlock(&btrfsic_mutex);
3325		return;
3326	}
3327
3328	/*
3329	 * Don't care about keeping the lists' state up to date,
3330	 * just free all memory that was allocated dynamically.
3331	 * Free the blocks and the block_links.
3332	 */
3333	list_for_each_safe(elem_all, tmp_all, &state->all_blocks_list) {
3334		struct btrfsic_block *const b_all =
3335		    list_entry(elem_all, struct btrfsic_block,
3336			       all_blocks_node);
3337		struct list_head *elem_ref_to;
3338		struct list_head *tmp_ref_to;
3339
3340		list_for_each_safe(elem_ref_to, tmp_ref_to,
3341				   &b_all->ref_to_list) {
3342			struct btrfsic_block_link *const l =
3343			    list_entry(elem_ref_to,
3344				       struct btrfsic_block_link,
3345				       node_ref_to);
3346
3347			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
3348				btrfsic_print_rem_link(state, l);
3349
3350			l->ref_cnt--;
3351			if (0 == l->ref_cnt)
3352				btrfsic_block_link_free(l);
3353		}
3354
3355		if (b_all->is_iodone || b_all->never_written)
3356			btrfsic_block_free(b_all);
3357		else
3358			printk(KERN_INFO "btrfs: attempt to free %c-block"
3359			       " @%llu (%s/%llu/%d) on umount which is"
3360			       " not yet iodone!\n",
3361			       btrfsic_get_block_type(state, b_all),
3362			       (unsigned long long)b_all->logical_bytenr,
3363			       b_all->dev_state->name,
3364			       (unsigned long long)b_all->dev_bytenr,
3365			       b_all->mirror_num);
3366	}
3367
3368	mutex_unlock(&btrfsic_mutex);
3369
3370	kfree(state);
3371}
3372