From 43318324d20cccccfacf2e82ac10e27eefb6cc95 Mon Sep 17 00:00:00 2001 From: Qu Wenruo Date: Mon, 22 Feb 2016 14:59:54 +0800 Subject: [PATCH] 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 [ adjusted error messages ] Signed-off-by: David Sterba --- ctree.h | 1 + disk-io.c | 29 ++++++++++++++++++++++++----- disk-io.h | 18 ++++++++++++++++-- 3 files changed, 41 insertions(+), 7 deletions(-) diff --git a/ctree.h b/ctree.h index 21b04458..5ab0f4a4 100644 --- a/ctree.h +++ b/ctree.h @@ -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, diff --git a/disk-io.c b/disk-io.c index bd0444b5..2ec62cf6 100644 --- a/disk-io.c +++ b/disk-io.c @@ -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); diff --git a/disk-io.h b/disk-io.h index d3e3aaac..c2eb1d6e 100644 --- a/disk-io.h +++ b/disk-io.h @@ -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);