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check-integrity.c
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/*
* Copyright (C) STRATO AG 2011. All rights reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public
* License v2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public
* License along with this program; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 021110-1307, USA.
*/
/*
* This module can be used to catch cases when the btrfs kernel
* code executes write requests to the disk that bring the file
* system in an inconsistent state. In such a state, a power-loss
* or kernel panic event would cause that the data on disk is
* lost or at least damaged.
*
* Code is added that examines all block write requests during
* runtime (including writes of the super block). Three rules
* are verified and an error is printed on violation of the
* rules:
* 1. It is not allowed to write a disk block which is
* currently referenced by the super block (either directly
* or indirectly).
* 2. When a super block is written, it is verified that all
* referenced (directly or indirectly) blocks fulfill the
* following requirements:
* 2a. All referenced blocks have either been present when
* the file system was mounted, (i.e., they have been
* referenced by the super block) or they have been
* written since then and the write completion callback
* was called and no write error was indicated and a
* FLUSH request to the device where these blocks are
* located was received and completed.
* 2b. All referenced blocks need to have a generation
* number which is equal to the parent's number.
*
* One issue that was found using this module was that the log
* tree on disk became temporarily corrupted because disk blocks
* that had been in use for the log tree had been freed and
* reused too early, while being referenced by the written super
* block.
*
* The search term in the kernel log that can be used to filter
* on the existence of detected integrity issues is
* "btrfs: attempt".
*
* The integrity check is enabled via mount options. These
* mount options are only supported if the integrity check
* tool is compiled by defining BTRFS_FS_CHECK_INTEGRITY.
*
* Example #1, apply integrity checks to all metadata:
* mount /dev/sdb1 /mnt -o check_int
*
* Example #2, apply integrity checks to all metadata and
* to data extents:
* mount /dev/sdb1 /mnt -o check_int_data
*
* Example #3, apply integrity checks to all metadata and dump
* the tree that the super block references to kernel messages
* each time after a super block was written:
* mount /dev/sdb1 /mnt -o check_int,check_int_print_mask=263
*
* If the integrity check tool is included and activated in
* the mount options, plenty of kernel memory is used, and
* plenty of additional CPU cycles are spent. Enabling this
* functionality is not intended for normal use. In most
* cases, unless you are a btrfs developer who needs to verify
* the integrity of (super)-block write requests, do not
* enable the config option BTRFS_FS_CHECK_INTEGRITY to
* include and compile the integrity check tool.
*/
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/buffer_head.h>
#include <linux/mutex.h>
#include <linux/crc32c.h>
#include <linux/genhd.h>
#include <linux/blkdev.h>
#include "ctree.h"
#include "disk-io.h"
#include "transaction.h"
#include "extent_io.h"
#include "volumes.h"
#include "print-tree.h"
#include "locking.h"
#include "check-integrity.h"
#include "rcu-string.h"
#define BTRFSIC_BLOCK_HASHTABLE_SIZE 0x10000
#define BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE 0x10000
#define BTRFSIC_DEV2STATE_HASHTABLE_SIZE 0x100
#define BTRFSIC_BLOCK_MAGIC_NUMBER 0x14491051
#define BTRFSIC_BLOCK_LINK_MAGIC_NUMBER 0x11070807
#define BTRFSIC_DEV2STATE_MAGIC_NUMBER 0x20111530
#define BTRFSIC_BLOCK_STACK_FRAME_MAGIC_NUMBER 20111300
#define BTRFSIC_TREE_DUMP_MAX_INDENT_LEVEL (200 - 6) /* in characters,
* excluding " [...]" */
#define BTRFSIC_GENERATION_UNKNOWN ((u64)-1)
/*
* The definition of the bitmask fields for the print_mask.
* They are specified with the mount option check_integrity_print_mask.
*/
#define BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE 0x00000001
#define BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION 0x00000002
#define BTRFSIC_PRINT_MASK_TREE_AFTER_SB_WRITE 0x00000004
#define BTRFSIC_PRINT_MASK_TREE_BEFORE_SB_WRITE 0x00000008
#define BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH 0x00000010
#define BTRFSIC_PRINT_MASK_END_IO_BIO_BH 0x00000020
#define BTRFSIC_PRINT_MASK_VERBOSE 0x00000040
#define BTRFSIC_PRINT_MASK_VERY_VERBOSE 0x00000080
#define BTRFSIC_PRINT_MASK_INITIAL_TREE 0x00000100
#define BTRFSIC_PRINT_MASK_INITIAL_ALL_TREES 0x00000200
#define BTRFSIC_PRINT_MASK_INITIAL_DATABASE 0x00000400
#define BTRFSIC_PRINT_MASK_NUM_COPIES 0x00000800
#define BTRFSIC_PRINT_MASK_TREE_WITH_ALL_MIRRORS 0x00001000
struct btrfsic_dev_state;
struct btrfsic_state;
struct btrfsic_block {
u32 magic_num; /* only used for debug purposes */
unsigned int is_metadata:1; /* if it is meta-data, not data-data */
unsigned int is_superblock:1; /* if it is one of the superblocks */
unsigned int is_iodone:1; /* if is done by lower subsystem */
unsigned int iodone_w_error:1; /* error was indicated to endio */
unsigned int never_written:1; /* block was added because it was
* referenced, not because it was
* written */
unsigned int mirror_num; /* large enough to hold
* BTRFS_SUPER_MIRROR_MAX */
struct btrfsic_dev_state *dev_state;
u64 dev_bytenr; /* key, physical byte num on disk */
u64 logical_bytenr; /* logical byte num on disk */
u64 generation;
struct btrfs_disk_key disk_key; /* extra info to print in case of
* issues, will not always be correct */
struct list_head collision_resolving_node; /* list node */
struct list_head all_blocks_node; /* list node */
/* the following two lists contain block_link items */
struct list_head ref_to_list; /* list */
struct list_head ref_from_list; /* list */
struct btrfsic_block *next_in_same_bio;
void *orig_bio_bh_private;
union {
bio_end_io_t *bio;
bh_end_io_t *bh;
} orig_bio_bh_end_io;
int submit_bio_bh_rw;
u64 flush_gen; /* only valid if !never_written */
};
/*
* Elements of this type are allocated dynamically and required because
* each block object can refer to and can be ref from multiple blocks.
* The key to lookup them in the hashtable is the dev_bytenr of
* the block ref to plus the one from the block refered from.
* The fact that they are searchable via a hashtable and that a
* ref_cnt is maintained is not required for the btrfs integrity
* check algorithm itself, it is only used to make the output more
* beautiful in case that an error is detected (an error is defined
* as a write operation to a block while that block is still referenced).
*/
struct btrfsic_block_link {
u32 magic_num; /* only used for debug purposes */
u32 ref_cnt;
struct list_head node_ref_to; /* list node */
struct list_head node_ref_from; /* list node */
struct list_head collision_resolving_node; /* list node */
struct btrfsic_block *block_ref_to;
struct btrfsic_block *block_ref_from;
u64 parent_generation;
};
struct btrfsic_dev_state {
u32 magic_num; /* only used for debug purposes */
struct block_device *bdev;
struct btrfsic_state *state;
struct list_head collision_resolving_node; /* list node */
struct btrfsic_block dummy_block_for_bio_bh_flush;
u64 last_flush_gen;
char name[BDEVNAME_SIZE];
};
struct btrfsic_block_hashtable {
struct list_head table[BTRFSIC_BLOCK_HASHTABLE_SIZE];
};
struct btrfsic_block_link_hashtable {
struct list_head table[BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE];
};
struct btrfsic_dev_state_hashtable {
struct list_head table[BTRFSIC_DEV2STATE_HASHTABLE_SIZE];
};
struct btrfsic_block_data_ctx {
u64 start; /* virtual bytenr */
u64 dev_bytenr; /* physical bytenr on device */
u32 len;
struct btrfsic_dev_state *dev;
char **datav;
struct page **pagev;
void *mem_to_free;
};
/* This structure is used to implement recursion without occupying
* any stack space, refer to btrfsic_process_metablock() */
struct btrfsic_stack_frame {
u32 magic;
u32 nr;
int error;
int i;
int limit_nesting;
int num_copies;
int mirror_num;
struct btrfsic_block *block;
struct btrfsic_block_data_ctx *block_ctx;
struct btrfsic_block *next_block;
struct btrfsic_block_data_ctx next_block_ctx;
struct btrfs_header *hdr;
struct btrfsic_stack_frame *prev;
};
/* Some state per mounted filesystem */
struct btrfsic_state {
u32 print_mask;
int include_extent_data;
int csum_size;
struct list_head all_blocks_list;
struct btrfsic_block_hashtable block_hashtable;
struct btrfsic_block_link_hashtable block_link_hashtable;
struct btrfs_root *root;
u64 max_superblock_generation;
struct btrfsic_block *latest_superblock;
u32 metablock_size;
u32 datablock_size;
};
static void btrfsic_block_init(struct btrfsic_block *b);
static struct btrfsic_block *btrfsic_block_alloc(void);
static void btrfsic_block_free(struct btrfsic_block *b);
static void btrfsic_block_link_init(struct btrfsic_block_link *n);
static struct btrfsic_block_link *btrfsic_block_link_alloc(void);
static void btrfsic_block_link_free(struct btrfsic_block_link *n);
static void btrfsic_dev_state_init(struct btrfsic_dev_state *ds);
static struct btrfsic_dev_state *btrfsic_dev_state_alloc(void);
static void btrfsic_dev_state_free(struct btrfsic_dev_state *ds);
static void btrfsic_block_hashtable_init(struct btrfsic_block_hashtable *h);
static void btrfsic_block_hashtable_add(struct btrfsic_block *b,
struct btrfsic_block_hashtable *h);
static void btrfsic_block_hashtable_remove(struct btrfsic_block *b);
static struct btrfsic_block *btrfsic_block_hashtable_lookup(
struct block_device *bdev,
u64 dev_bytenr,
struct btrfsic_block_hashtable *h);
static void btrfsic_block_link_hashtable_init(
struct btrfsic_block_link_hashtable *h);
static void btrfsic_block_link_hashtable_add(
struct btrfsic_block_link *l,
struct btrfsic_block_link_hashtable *h);
static void btrfsic_block_link_hashtable_remove(struct btrfsic_block_link *l);
static struct btrfsic_block_link *btrfsic_block_link_hashtable_lookup(
struct block_device *bdev_ref_to,
u64 dev_bytenr_ref_to,
struct block_device *bdev_ref_from,
u64 dev_bytenr_ref_from,
struct btrfsic_block_link_hashtable *h);
static void btrfsic_dev_state_hashtable_init(
struct btrfsic_dev_state_hashtable *h);
static void btrfsic_dev_state_hashtable_add(
struct btrfsic_dev_state *ds,
struct btrfsic_dev_state_hashtable *h);
static void btrfsic_dev_state_hashtable_remove(struct btrfsic_dev_state *ds);
static struct btrfsic_dev_state *btrfsic_dev_state_hashtable_lookup(
struct block_device *bdev,
struct btrfsic_dev_state_hashtable *h);
static struct btrfsic_stack_frame *btrfsic_stack_frame_alloc(void);
static void btrfsic_stack_frame_free(struct btrfsic_stack_frame *sf);
static int btrfsic_process_superblock(struct btrfsic_state *state,
struct btrfs_fs_devices *fs_devices);
static int btrfsic_process_metablock(struct btrfsic_state *state,
struct btrfsic_block *block,
struct btrfsic_block_data_ctx *block_ctx,
int limit_nesting, int force_iodone_flag);
static void btrfsic_read_from_block_data(
struct btrfsic_block_data_ctx *block_ctx,
void *dst, u32 offset, size_t len);
static int btrfsic_create_link_to_next_block(
struct btrfsic_state *state,
struct btrfsic_block *block,
struct btrfsic_block_data_ctx
*block_ctx, u64 next_bytenr,
int limit_nesting,
struct btrfsic_block_data_ctx *next_block_ctx,
struct btrfsic_block **next_blockp,
int force_iodone_flag,
int *num_copiesp, int *mirror_nump,
struct btrfs_disk_key *disk_key,
u64 parent_generation);
static int btrfsic_handle_extent_data(struct btrfsic_state *state,
struct btrfsic_block *block,
struct btrfsic_block_data_ctx *block_ctx,
u32 item_offset, int force_iodone_flag);
static int btrfsic_map_block(struct btrfsic_state *state, u64 bytenr, u32 len,
struct btrfsic_block_data_ctx *block_ctx_out,
int mirror_num);
static int btrfsic_map_superblock(struct btrfsic_state *state, u64 bytenr,
u32 len, struct block_device *bdev,
struct btrfsic_block_data_ctx *block_ctx_out);
static void btrfsic_release_block_ctx(struct btrfsic_block_data_ctx *block_ctx);
static int btrfsic_read_block(struct btrfsic_state *state,
struct btrfsic_block_data_ctx *block_ctx);
static void btrfsic_dump_database(struct btrfsic_state *state);
static void btrfsic_complete_bio_end_io(struct bio *bio, int err);
static int btrfsic_test_for_metadata(struct btrfsic_state *state,
char **datav, unsigned int num_pages);
static void btrfsic_process_written_block(struct btrfsic_dev_state *dev_state,
u64 dev_bytenr, char **mapped_datav,
unsigned int num_pages,
struct bio *bio, int *bio_is_patched,
struct buffer_head *bh,
int submit_bio_bh_rw);
static int btrfsic_process_written_superblock(
struct btrfsic_state *state,
struct btrfsic_block *const block,
struct btrfs_super_block *const super_hdr);
static void btrfsic_bio_end_io(struct bio *bp, int bio_error_status);
static void btrfsic_bh_end_io(struct buffer_head *bh, int uptodate);
static int btrfsic_is_block_ref_by_superblock(const struct btrfsic_state *state,
const struct btrfsic_block *block,
int recursion_level);
static int btrfsic_check_all_ref_blocks(struct btrfsic_state *state,
struct btrfsic_block *const block,
int recursion_level);
static void btrfsic_print_add_link(const struct btrfsic_state *state,
const struct btrfsic_block_link *l);
static void btrfsic_print_rem_link(const struct btrfsic_state *state,
const struct btrfsic_block_link *l);
static char btrfsic_get_block_type(const struct btrfsic_state *state,
const struct btrfsic_block *block);
static void btrfsic_dump_tree(const struct btrfsic_state *state);
static void btrfsic_dump_tree_sub(const struct btrfsic_state *state,
const struct btrfsic_block *block,
int indent_level);
static struct btrfsic_block_link *btrfsic_block_link_lookup_or_add(
struct btrfsic_state *state,
struct btrfsic_block_data_ctx *next_block_ctx,
struct btrfsic_block *next_block,
struct btrfsic_block *from_block,
u64 parent_generation);
static struct btrfsic_block *btrfsic_block_lookup_or_add(
struct btrfsic_state *state,
struct btrfsic_block_data_ctx *block_ctx,
const char *additional_string,
int is_metadata,
int is_iodone,
int never_written,
int mirror_num,
int *was_created);
static int btrfsic_process_superblock_dev_mirror(
struct btrfsic_state *state,
struct btrfsic_dev_state *dev_state,
struct btrfs_device *device,
int superblock_mirror_num,
struct btrfsic_dev_state **selected_dev_state,
struct btrfs_super_block *selected_super);
static struct btrfsic_dev_state *btrfsic_dev_state_lookup(
struct block_device *bdev);
static void btrfsic_cmp_log_and_dev_bytenr(struct btrfsic_state *state,
u64 bytenr,
struct btrfsic_dev_state *dev_state,
u64 dev_bytenr);
static struct mutex btrfsic_mutex;
static int btrfsic_is_initialized;
static struct btrfsic_dev_state_hashtable btrfsic_dev_state_hashtable;
static void btrfsic_block_init(struct btrfsic_block *b)
{
b->magic_num = BTRFSIC_BLOCK_MAGIC_NUMBER;
b->dev_state = NULL;
b->dev_bytenr = 0;
b->logical_bytenr = 0;
b->generation = BTRFSIC_GENERATION_UNKNOWN;
b->disk_key.objectid = 0;
b->disk_key.type = 0;
b->disk_key.offset = 0;
b->is_metadata = 0;
b->is_superblock = 0;
b->is_iodone = 0;
b->iodone_w_error = 0;
b->never_written = 0;
b->mirror_num = 0;
b->next_in_same_bio = NULL;
b->orig_bio_bh_private = NULL;
b->orig_bio_bh_end_io.bio = NULL;
INIT_LIST_HEAD(&b->collision_resolving_node);
INIT_LIST_HEAD(&b->all_blocks_node);
INIT_LIST_HEAD(&b->ref_to_list);
INIT_LIST_HEAD(&b->ref_from_list);
b->submit_bio_bh_rw = 0;
b->flush_gen = 0;
}
static struct btrfsic_block *btrfsic_block_alloc(void)
{
struct btrfsic_block *b;
b = kzalloc(sizeof(*b), GFP_NOFS);
if (NULL != b)
btrfsic_block_init(b);
return b;
}
static void btrfsic_block_free(struct btrfsic_block *b)
{
BUG_ON(!(NULL == b || BTRFSIC_BLOCK_MAGIC_NUMBER == b->magic_num));
kfree(b);
}
static void btrfsic_block_link_init(struct btrfsic_block_link *l)
{
l->magic_num = BTRFSIC_BLOCK_LINK_MAGIC_NUMBER;
l->ref_cnt = 1;
INIT_LIST_HEAD(&l->node_ref_to);
INIT_LIST_HEAD(&l->node_ref_from);
INIT_LIST_HEAD(&l->collision_resolving_node);
l->block_ref_to = NULL;
l->block_ref_from = NULL;
}
static struct btrfsic_block_link *btrfsic_block_link_alloc(void)
{
struct btrfsic_block_link *l;
l = kzalloc(sizeof(*l), GFP_NOFS);
if (NULL != l)
btrfsic_block_link_init(l);
return l;
}
static void btrfsic_block_link_free(struct btrfsic_block_link *l)
{
BUG_ON(!(NULL == l || BTRFSIC_BLOCK_LINK_MAGIC_NUMBER == l->magic_num));
kfree(l);
}
static void btrfsic_dev_state_init(struct btrfsic_dev_state *ds)
{
ds->magic_num = BTRFSIC_DEV2STATE_MAGIC_NUMBER;
ds->bdev = NULL;
ds->state = NULL;
ds->name[0] = '\0';
INIT_LIST_HEAD(&ds->collision_resolving_node);
ds->last_flush_gen = 0;
btrfsic_block_init(&ds->dummy_block_for_bio_bh_flush);
ds->dummy_block_for_bio_bh_flush.is_iodone = 1;
ds->dummy_block_for_bio_bh_flush.dev_state = ds;
}
static struct btrfsic_dev_state *btrfsic_dev_state_alloc(void)
{
struct btrfsic_dev_state *ds;
ds = kzalloc(sizeof(*ds), GFP_NOFS);
if (NULL != ds)
btrfsic_dev_state_init(ds);
return ds;
}
static void btrfsic_dev_state_free(struct btrfsic_dev_state *ds)
{
BUG_ON(!(NULL == ds ||
BTRFSIC_DEV2STATE_MAGIC_NUMBER == ds->magic_num));
kfree(ds);
}
static void btrfsic_block_hashtable_init(struct btrfsic_block_hashtable *h)
{
int i;
for (i = 0; i < BTRFSIC_BLOCK_HASHTABLE_SIZE; i++)
INIT_LIST_HEAD(h->table + i);
}
static void btrfsic_block_hashtable_add(struct btrfsic_block *b,
struct btrfsic_block_hashtable *h)
{
const unsigned int hashval =
(((unsigned int)(b->dev_bytenr >> 16)) ^
((unsigned int)((uintptr_t)b->dev_state->bdev))) &
(BTRFSIC_BLOCK_HASHTABLE_SIZE - 1);
list_add(&b->collision_resolving_node, h->table + hashval);
}
static void btrfsic_block_hashtable_remove(struct btrfsic_block *b)
{
list_del(&b->collision_resolving_node);
}
static struct btrfsic_block *btrfsic_block_hashtable_lookup(
struct block_device *bdev,
u64 dev_bytenr,
struct btrfsic_block_hashtable *h)
{
const unsigned int hashval =
(((unsigned int)(dev_bytenr >> 16)) ^
((unsigned int)((uintptr_t)bdev))) &
(BTRFSIC_BLOCK_HASHTABLE_SIZE - 1);
struct list_head *elem;
list_for_each(elem, h->table + hashval) {
struct btrfsic_block *const b =
list_entry(elem, struct btrfsic_block,
collision_resolving_node);
if (b->dev_state->bdev == bdev && b->dev_bytenr == dev_bytenr)
return b;
}
return NULL;
}
static void btrfsic_block_link_hashtable_init(
struct btrfsic_block_link_hashtable *h)
{
int i;
for (i = 0; i < BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE; i++)
INIT_LIST_HEAD(h->table + i);
}
static void btrfsic_block_link_hashtable_add(
struct btrfsic_block_link *l,
struct btrfsic_block_link_hashtable *h)
{
const unsigned int hashval =
(((unsigned int)(l->block_ref_to->dev_bytenr >> 16)) ^
((unsigned int)(l->block_ref_from->dev_bytenr >> 16)) ^
((unsigned int)((uintptr_t)l->block_ref_to->dev_state->bdev)) ^
((unsigned int)((uintptr_t)l->block_ref_from->dev_state->bdev)))
& (BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE - 1);
BUG_ON(NULL == l->block_ref_to);
BUG_ON(NULL == l->block_ref_from);
list_add(&l->collision_resolving_node, h->table + hashval);
}
static void btrfsic_block_link_hashtable_remove(struct btrfsic_block_link *l)
{
list_del(&l->collision_resolving_node);
}
static struct btrfsic_block_link *btrfsic_block_link_hashtable_lookup(
struct block_device *bdev_ref_to,
u64 dev_bytenr_ref_to,
struct block_device *bdev_ref_from,
u64 dev_bytenr_ref_from,
struct btrfsic_block_link_hashtable *h)
{
const unsigned int hashval =
(((unsigned int)(dev_bytenr_ref_to >> 16)) ^
((unsigned int)(dev_bytenr_ref_from >> 16)) ^
((unsigned int)((uintptr_t)bdev_ref_to)) ^
((unsigned int)((uintptr_t)bdev_ref_from))) &
(BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE - 1);
struct list_head *elem;
list_for_each(elem, h->table + hashval) {
struct btrfsic_block_link *const l =
list_entry(elem, struct btrfsic_block_link,
collision_resolving_node);
BUG_ON(NULL == l->block_ref_to);
BUG_ON(NULL == l->block_ref_from);
if (l->block_ref_to->dev_state->bdev == bdev_ref_to &&
l->block_ref_to->dev_bytenr == dev_bytenr_ref_to &&
l->block_ref_from->dev_state->bdev == bdev_ref_from &&
l->block_ref_from->dev_bytenr == dev_bytenr_ref_from)
return l;
}
return NULL;
}
static void btrfsic_dev_state_hashtable_init(
struct btrfsic_dev_state_hashtable *h)
{
int i;
for (i = 0; i < BTRFSIC_DEV2STATE_HASHTABLE_SIZE; i++)
INIT_LIST_HEAD(h->table + i);
}
static void btrfsic_dev_state_hashtable_add(
struct btrfsic_dev_state *ds,
struct btrfsic_dev_state_hashtable *h)
{
const unsigned int hashval =
(((unsigned int)((uintptr_t)ds->bdev)) &
(BTRFSIC_DEV2STATE_HASHTABLE_SIZE - 1));
list_add(&ds->collision_resolving_node, h->table + hashval);
}
static void btrfsic_dev_state_hashtable_remove(struct btrfsic_dev_state *ds)
{
list_del(&ds->collision_resolving_node);
}
static struct btrfsic_dev_state *btrfsic_dev_state_hashtable_lookup(
struct block_device *bdev,
struct btrfsic_dev_state_hashtable *h)
{
const unsigned int hashval =
(((unsigned int)((uintptr_t)bdev)) &
(BTRFSIC_DEV2STATE_HASHTABLE_SIZE - 1));
struct list_head *elem;
list_for_each(elem, h->table + hashval) {
struct btrfsic_dev_state *const ds =
list_entry(elem, struct btrfsic_dev_state,
collision_resolving_node);
if (ds->bdev == bdev)
return ds;
}
return NULL;
}
static int btrfsic_process_superblock(struct btrfsic_state *state,
struct btrfs_fs_devices *fs_devices)
{
int ret = 0;
struct btrfs_super_block *selected_super;
struct list_head *dev_head = &fs_devices->devices;
struct btrfs_device *device;
struct btrfsic_dev_state *selected_dev_state = NULL;
int pass;
BUG_ON(NULL == state);
selected_super = kzalloc(sizeof(*selected_super), GFP_NOFS);
if (NULL == selected_super) {
printk(KERN_INFO "btrfsic: error, kmalloc failed!\n");
return -1;
}
list_for_each_entry(device, dev_head, dev_list) {
int i;
struct btrfsic_dev_state *dev_state;
if (!device->bdev || !device->name)
continue;
dev_state = btrfsic_dev_state_lookup(device->bdev);
BUG_ON(NULL == dev_state);
for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
ret = btrfsic_process_superblock_dev_mirror(
state, dev_state, device, i,
&selected_dev_state, selected_super);
if (0 != ret && 0 == i) {
kfree(selected_super);
return ret;
}
}
}
if (NULL == state->latest_superblock) {
printk(KERN_INFO "btrfsic: no superblock found!\n");
kfree(selected_super);
return -1;
}
state->csum_size = btrfs_super_csum_size(selected_super);
for (pass = 0; pass < 3; pass++) {
int num_copies;
int mirror_num;
u64 next_bytenr;
switch (pass) {
case 0:
next_bytenr = btrfs_super_root(selected_super);
if (state->print_mask &
BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
printk(KERN_INFO "root@%llu\n",
(unsigned long long)next_bytenr);
break;
case 1:
next_bytenr = btrfs_super_chunk_root(selected_super);
if (state->print_mask &
BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
printk(KERN_INFO "chunk@%llu\n",
(unsigned long long)next_bytenr);
break;
case 2:
next_bytenr = btrfs_super_log_root(selected_super);
if (0 == next_bytenr)
continue;
if (state->print_mask &
BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
printk(KERN_INFO "log@%llu\n",
(unsigned long long)next_bytenr);
break;
}
num_copies =
btrfs_num_copies(state->root->fs_info,
next_bytenr, state->metablock_size);
if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
printk(KERN_INFO "num_copies(log_bytenr=%llu) = %d\n",
(unsigned long long)next_bytenr, num_copies);
for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
struct btrfsic_block *next_block;
struct btrfsic_block_data_ctx tmp_next_block_ctx;
struct btrfsic_block_link *l;
ret = btrfsic_map_block(state, next_bytenr,
state->metablock_size,
&tmp_next_block_ctx,
mirror_num);
if (ret) {
printk(KERN_INFO "btrfsic:"
" btrfsic_map_block(root @%llu,"
" mirror %d) failed!\n",
(unsigned long long)next_bytenr,
mirror_num);
kfree(selected_super);
return -1;
}
next_block = btrfsic_block_hashtable_lookup(
tmp_next_block_ctx.dev->bdev,
tmp_next_block_ctx.dev_bytenr,
&state->block_hashtable);
BUG_ON(NULL == next_block);
l = btrfsic_block_link_hashtable_lookup(
tmp_next_block_ctx.dev->bdev,
tmp_next_block_ctx.dev_bytenr,
state->latest_superblock->dev_state->
bdev,
state->latest_superblock->dev_bytenr,
&state->block_link_hashtable);
BUG_ON(NULL == l);
ret = btrfsic_read_block(state, &tmp_next_block_ctx);
if (ret < (int)PAGE_CACHE_SIZE) {
printk(KERN_INFO
"btrfsic: read @logical %llu failed!\n",
(unsigned long long)
tmp_next_block_ctx.start);
btrfsic_release_block_ctx(&tmp_next_block_ctx);
kfree(selected_super);
return -1;
}
ret = btrfsic_process_metablock(state,
next_block,
&tmp_next_block_ctx,
BTRFS_MAX_LEVEL + 3, 1);
btrfsic_release_block_ctx(&tmp_next_block_ctx);
}
}
kfree(selected_super);
return ret;
}
static int btrfsic_process_superblock_dev_mirror(
struct btrfsic_state *state,
struct btrfsic_dev_state *dev_state,
struct btrfs_device *device,
int superblock_mirror_num,
struct btrfsic_dev_state **selected_dev_state,
struct btrfs_super_block *selected_super)
{
struct btrfs_super_block *super_tmp;
u64 dev_bytenr;
struct buffer_head *bh;
struct btrfsic_block *superblock_tmp;
int pass;
struct block_device *const superblock_bdev = device->bdev;
/* super block bytenr is always the unmapped device bytenr */
dev_bytenr = btrfs_sb_offset(superblock_mirror_num);
if (dev_bytenr + BTRFS_SUPER_INFO_SIZE > device->total_bytes)
return -1;
bh = __bread(superblock_bdev, dev_bytenr / 4096,
BTRFS_SUPER_INFO_SIZE);
if (NULL == bh)
return -1;
super_tmp = (struct btrfs_super_block *)
(bh->b_data + (dev_bytenr & 4095));
if (btrfs_super_bytenr(super_tmp) != dev_bytenr ||
super_tmp->magic != cpu_to_le64(BTRFS_MAGIC) ||
memcmp(device->uuid, super_tmp->dev_item.uuid, BTRFS_UUID_SIZE) ||
btrfs_super_nodesize(super_tmp) != state->metablock_size ||
btrfs_super_leafsize(super_tmp) != state->metablock_size ||
btrfs_super_sectorsize(super_tmp) != state->datablock_size) {
brelse(bh);
return 0;
}
superblock_tmp =
btrfsic_block_hashtable_lookup(superblock_bdev,
dev_bytenr,
&state->block_hashtable);
if (NULL == superblock_tmp) {
superblock_tmp = btrfsic_block_alloc();
if (NULL == superblock_tmp) {
printk(KERN_INFO "btrfsic: error, kmalloc failed!\n");
brelse(bh);
return -1;
}
/* for superblock, only the dev_bytenr makes sense */
superblock_tmp->dev_bytenr = dev_bytenr;
superblock_tmp->dev_state = dev_state;
superblock_tmp->logical_bytenr = dev_bytenr;
superblock_tmp->generation = btrfs_super_generation(super_tmp);
superblock_tmp->is_metadata = 1;
superblock_tmp->is_superblock = 1;
superblock_tmp->is_iodone = 1;
superblock_tmp->never_written = 0;
superblock_tmp->mirror_num = 1 + superblock_mirror_num;
if (state->print_mask & BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE)
printk_in_rcu(KERN_INFO "New initial S-block (bdev %p, %s)"
" @%llu (%s/%llu/%d)\n",
superblock_bdev,
rcu_str_deref(device->name),
(unsigned long long)dev_bytenr,
dev_state->name,
(unsigned long long)dev_bytenr,
superblock_mirror_num);
list_add(&superblock_tmp->all_blocks_node,
&state->all_blocks_list);
btrfsic_block_hashtable_add(superblock_tmp,
&state->block_hashtable);
}
/* select the one with the highest generation field */
if (btrfs_super_generation(super_tmp) >
state->max_superblock_generation ||
0 == state->max_superblock_generation) {
memcpy(selected_super, super_tmp, sizeof(*selected_super));
*selected_dev_state = dev_state;
state->max_superblock_generation =
btrfs_super_generation(super_tmp);
state->latest_superblock = superblock_tmp;
}
for (pass = 0; pass < 3; pass++) {
u64 next_bytenr;
int num_copies;
int mirror_num;
const char *additional_string = NULL;
struct btrfs_disk_key tmp_disk_key;
tmp_disk_key.type = BTRFS_ROOT_ITEM_KEY;
tmp_disk_key.offset = 0;
switch (pass) {
case 0:
tmp_disk_key.objectid =
cpu_to_le64(BTRFS_ROOT_TREE_OBJECTID);
additional_string = "initial root ";
next_bytenr = btrfs_super_root(super_tmp);
break;
case 1:
tmp_disk_key.objectid =
cpu_to_le64(BTRFS_CHUNK_TREE_OBJECTID);
additional_string = "initial chunk ";
next_bytenr = btrfs_super_chunk_root(super_tmp);
break;
case 2:
tmp_disk_key.objectid =
cpu_to_le64(BTRFS_TREE_LOG_OBJECTID);
additional_string = "initial log ";
next_bytenr = btrfs_super_log_root(super_tmp);
if (0 == next_bytenr)
continue;
break;
}
num_copies =
btrfs_num_copies(state->root->fs_info,
next_bytenr, state->metablock_size);
if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
printk(KERN_INFO "num_copies(log_bytenr=%llu) = %d\n",
(unsigned long long)next_bytenr, num_copies);
for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
struct btrfsic_block *next_block;
struct btrfsic_block_data_ctx tmp_next_block_ctx;
struct btrfsic_block_link *l;
if (btrfsic_map_block(state, next_bytenr,
state->metablock_size,
&tmp_next_block_ctx,
mirror_num)) {
printk(KERN_INFO "btrfsic: btrfsic_map_block("
"bytenr @%llu, mirror %d) failed!\n",
(unsigned long long)next_bytenr,
mirror_num);
brelse(bh);
return -1;
}
next_block = btrfsic_block_lookup_or_add(
state, &tmp_next_block_ctx,
additional_string, 1, 1, 0,
mirror_num, NULL);
if (NULL == next_block) {
btrfsic_release_block_ctx(&tmp_next_block_ctx);
brelse(bh);
return -1;
}
next_block->disk_key = tmp_disk_key;
next_block->generation = BTRFSIC_GENERATION_UNKNOWN;
l = btrfsic_block_link_lookup_or_add(
state, &tmp_next_block_ctx,
next_block, superblock_tmp,
BTRFSIC_GENERATION_UNKNOWN);
btrfsic_release_block_ctx(&tmp_next_block_ctx);
if (NULL == l) {
brelse(bh);
return -1;
}
}
}
if (state->print_mask & BTRFSIC_PRINT_MASK_INITIAL_ALL_TREES)
btrfsic_dump_tree_sub(state, superblock_tmp, 0);
brelse(bh);
return 0;
}
static struct btrfsic_stack_frame *btrfsic_stack_frame_alloc(void)
{
struct btrfsic_stack_frame *sf;
sf = kzalloc(sizeof(*sf), GFP_NOFS);
if (NULL == sf)
printk(KERN_INFO "btrfsic: alloc memory failed!\n");
else
sf->magic = BTRFSIC_BLOCK_STACK_FRAME_MAGIC_NUMBER;
return sf;
}
static void btrfsic_stack_frame_free(struct btrfsic_stack_frame *sf)
{
BUG_ON(!(NULL == sf ||
BTRFSIC_BLOCK_STACK_FRAME_MAGIC_NUMBER == sf->magic));
kfree(sf);
}
static int btrfsic_process_metablock(
struct btrfsic_state *state,
struct btrfsic_block *const first_block,
struct btrfsic_block_data_ctx *const first_block_ctx,
int first_limit_nesting, int force_iodone_flag)
{
struct btrfsic_stack_frame initial_stack_frame = { 0 };
struct btrfsic_stack_frame *sf;
struct btrfsic_stack_frame *next_stack;
struct btrfs_header *const first_hdr =
(struct btrfs_header *)first_block_ctx->datav[0];
BUG_ON(!first_hdr);
sf = &initial_stack_frame;
sf->error = 0;
sf->i = -1;
sf->limit_nesting = first_limit_nesting;
sf->block = first_block;
sf->block_ctx = first_block_ctx;
sf->next_block = NULL;
sf->hdr = first_hdr;
sf->prev = NULL;
continue_with_new_stack_frame:
sf->block->generation = le64_to_cpu(sf->hdr->generation);