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btrfs-progs: Allow open_ctree to return fs_info even chunk tree is corrupted 

Current open_ctree_fs_info() won't return anything if chunk tree root is
corrupted.
This makes some function, like btrfs-find-root, unable to find any older
chunk tree root, even it is possible to use system_chunk_array in super
block.

And at least two users in mail list has reported such heavily chunk
corruption.
Although we have 'btrfs rescue chunk-recovery' but it's too time
consuming and sometimes not able to cope with a specific filesystem
corruption.

This patch adds a new open ctree flag,
OPEN_CTREE_IGNORE_CHUNK_TREE_ERROR, allowing fs_info to be returned from
open_ctree_fs_info() even there is no valid tree root in it.

Also adds a new close_ctree() variant, close_ctree_fs_info() to handle
possible fs_info without any root.

Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
[ adjusted error messages ]
Signed-off-by: David Sterba <dsterba@suse.com>
master
Qu Wenruo 2016-02-22 14:59:54 +08:00 committed by David Sterba
parent e2e0dae926
commit 43318324d2
3 changed files with 41 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
ctree.h
View File

@ -1029,6 +1029,7 @@ struct btrfs_fs_info {
unsigned int quota_enabled:1;
unsigned int suppress_check_block_errors:1;
unsigned int ignore_fsid_mismatch:1;
unsigned int ignore_chunk_tree_error:1;
int (*free_extent_hook)(struct btrfs_trans_handle *trans,
struct btrfs_root *root,

29
disk-io.c
View File

@ -1168,8 +1168,14 @@ int btrfs_setup_chunk_tree_and_device_map(struct btrfs_fs_info *fs_info)
btrfs_super_chunk_root(sb),
blocksize, generation);
if (!extent_buffer_uptodate(fs_info->chunk_root->node)) {
fprintf(stderr, "Couldn't read chunk root\n");
return -EIO;
if (fs_info->ignore_chunk_tree_error) {
warning("cannot read chunk root, continue anyway");
fs_info->chunk_root = NULL;
return 0;
} else {
error("cannot read chunk root");
return -EIO;
}
}
if (!(btrfs_super_flags(sb) & BTRFS_SUPER_FLAG_METADUMP)) {
@ -1212,6 +1218,8 @@ static struct btrfs_fs_info *__open_ctree_fd(int fp, const char *path,
fs_info->suppress_check_block_errors = 1;
if (flags & OPEN_CTREE_IGNORE_FSID_MISMATCH)
fs_info->ignore_fsid_mismatch = 1;
if (flags & OPEN_CTREE_IGNORE_CHUNK_TREE_ERROR)
fs_info->ignore_chunk_tree_error = 1;
ret = btrfs_scan_fs_devices(fp, path, &fs_devices, sb_bytenr,
(flags & OPEN_CTREE_RECOVER_SUPER),
@ -1260,13 +1268,18 @@ static struct btrfs_fs_info *__open_ctree_fd(int fp, const char *path,
if (ret)
goto out_chunk;
/* Chunk tree root is unable to read, return directly */
if (!fs_info->chunk_root)
return fs_info;
eb = fs_info->chunk_root->node;
read_extent_buffer(eb, fs_info->chunk_tree_uuid,
btrfs_header_chunk_tree_uuid(eb),
BTRFS_UUID_SIZE);
ret = btrfs_setup_all_roots(fs_info, root_tree_bytenr, flags);
if (ret && !(flags & __OPEN_CTREE_RETURN_CHUNK_ROOT))
if (ret && !(flags & __OPEN_CTREE_RETURN_CHUNK_ROOT) &&
!fs_info->ignore_chunk_tree_error)
goto out_chunk;
return fs_info;
@ -1308,6 +1321,8 @@ struct btrfs_root *open_ctree(const char *filename, u64 sb_bytenr,
{
struct btrfs_fs_info *info;
/* This flags may not return fs_info with any valid root */
BUG_ON(flags & OPEN_CTREE_IGNORE_CHUNK_TREE_ERROR);
info = open_ctree_fs_info(filename, sb_bytenr, 0, flags);
if (!info)
return NULL;
@ -1320,6 +1335,9 @@ struct btrfs_root *open_ctree_fd(int fp, const char *path, u64 sb_bytenr,
enum btrfs_open_ctree_flags flags)
{
struct btrfs_fs_info *info;
/* This flags may not return fs_info with any valid root */
BUG_ON(flags & OPEN_CTREE_IGNORE_CHUNK_TREE_ERROR);
info = __open_ctree_fd(fp, path, sb_bytenr, 0, flags);
if (!info)
return NULL;
@ -1658,14 +1676,15 @@ int write_ctree_super(struct btrfs_trans_handle *trans,
return ret;
}
int close_ctree(struct btrfs_root *root)
int close_ctree_fs_info(struct btrfs_fs_info *fs_info)
{
int ret;
struct btrfs_trans_handle *trans;
struct btrfs_fs_info *fs_info = root->fs_info;
struct btrfs_root *root = fs_info->tree_root;
if (fs_info->last_trans_committed !=
fs_info->generation) {
BUG_ON(!root);
trans = btrfs_start_transaction(root, 1);
btrfs_commit_transaction(trans, root);
trans = btrfs_start_transaction(root, 1);

18
disk-io.h
View File

@ -53,7 +53,15 @@ enum btrfs_open_ctree_flags {
* Like split PARTIAL into SKIP_CSUM/SKIP_EXTENT
*/
OPEN_CTREE_IGNORE_FSID_MISMATCH = (1 << 10)
OPEN_CTREE_IGNORE_FSID_MISMATCH = (1 << 10),
/*
* Allow open_ctree_fs_info() to return a incomplete fs_info with
* system chunks from super block only.
* It's useful for chunk corruption case.
* Makes no sense for open_ctree variants returning btrfs_root.
*/
OPEN_CTREE_IGNORE_CHUNK_TREE_ERROR = (1 << 11)
};
static inline u64 btrfs_sb_offset(int mirror)
@ -101,7 +109,13 @@ struct btrfs_root *open_ctree_fd(int fp, const char *path, u64 sb_bytenr,
struct btrfs_fs_info *open_ctree_fs_info(const char *filename,
u64 sb_bytenr, u64 root_tree_bytenr,
enum btrfs_open_ctree_flags flags);
int close_ctree(struct btrfs_root *root);
int close_ctree_fs_info(struct btrfs_fs_info *fs_info);
static inline int close_ctree(struct btrfs_root *root)
{
BUG_ON(!root);
return close_ctree_fs_info(root->fs_info);
}
int write_all_supers(struct btrfs_root *root);
int write_ctree_super(struct btrfs_trans_handle *trans,
struct btrfs_root *root);