| Message ID | 20190612063657.21063-4-wqu@suse.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | btrfs: Introduce new rescue= mount options | expand |
On Wed, Jun 12, 2019 at 02:36:57PM +0800, Qu Wenruo wrote: > [PROBLEM] > There are some reports of corrupted fs which can't be mounted due to > corrupted extent tree. > > However under such situation, it's more likely the fs/subvolume trees > are still fine. > > For such case we normally go btrfs-restore and salvage as much as we > can. However btrfs-restore can't list subvolumes as "btrfs subv list", > making it harder to restore a fs. > > [ENHANCEMENT] > This patch will introduce a new mount option "rescue=skip_bg" to skip > the mount time block group scan, and use chunk info purely to populate > fake block group cache. > > The mount option has the following dependency: > - RO mount > Obviously. > > - No dirty log. > Either there is no log, or use rescue=no_log_replay mount option. > > - No way to remoutn RW > Similar to rescue=no_log_replay option. > > This should allow kernel to accept most extent tree corruption, and > salvage data and subvolume info. > > Signed-off-by: Qu Wenruo <wqu@suse.com> > --- > fs/btrfs/ctree.h | 1 + > fs/btrfs/disk-io.c | 29 ++++++++++++++++++++---- > fs/btrfs/extent-tree.c | 50 ++++++++++++++++++++++++++++++++++++++++++ > fs/btrfs/super.c | 24 +++++++++++++++++++- > fs/btrfs/volumes.c | 7 ++++++ > 5 files changed, 106 insertions(+), 5 deletions(-) > > diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h > index 0a61dff27f57..9413db8c9bf0 100644 > --- a/fs/btrfs/ctree.h > +++ b/fs/btrfs/ctree.h > @@ -1441,6 +1441,7 @@ static inline u32 BTRFS_MAX_XATTR_SIZE(const struct btrfs_fs_info *info) > #define BTRFS_MOUNT_FREE_SPACE_TREE (1 << 26) > #define BTRFS_MOUNT_NOLOGREPLAY (1 << 27) > #define BTRFS_MOUNT_REF_VERIFY (1 << 28) > +#define BTRFS_MOUNT_SKIP_BG (1 << 29) > > #define BTRFS_DEFAULT_COMMIT_INTERVAL (30) > #define BTRFS_DEFAULT_MAX_INLINE (2048) > diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c > index deb74a8c191a..9701bf8ffbda 100644 > --- a/fs/btrfs/disk-io.c > +++ b/fs/btrfs/disk-io.c > @@ -2330,11 +2330,15 @@ static int btrfs_read_roots(struct btrfs_fs_info *fs_info) > > root = btrfs_read_tree_root(tree_root, &location); > if (IS_ERR(root)) { > - ret = PTR_ERR(root); > - goto out; > + if (!btrfs_test_opt(fs_info, SKIP_BG)) { > + ret = PTR_ERR(root); > + goto out; > + } > + fs_info->extent_root = NULL; > + } else { > + set_bit(BTRFS_ROOT_TRACK_DIRTY, &root->state); > + fs_info->extent_root = root; > } > - set_bit(BTRFS_ROOT_TRACK_DIRTY, &root->state); > - fs_info->extent_root = root; > > location.objectid = BTRFS_DEV_TREE_OBJECTID; > root = btrfs_read_tree_root(tree_root, &location); > @@ -2956,6 +2960,23 @@ int open_ctree(struct super_block *sb, > goto fail_alloc; > } > > + /* Skip bg needs RO and no log tree replay */ > + if (btrfs_test_opt(fs_info, SKIP_BG)) { > + if (!sb_rdonly(sb)) { > + btrfs_err(fs_info, > + "skip_bg mount option can only be used with read-only mount"); > + err = -EINVAL; > + goto fail_alloc; > + } > + if (btrfs_super_log_root(disk_super) && > + !btrfs_test_opt(fs_info, NOTREELOG)) { > + btrfs_err(fs_info, > + "skip_bg must be used with notreelog mount option for dirty log"); > + err = -EINVAL; > + goto fail_alloc; > + } > + } > + > ret = btrfs_init_workqueues(fs_info, fs_devices); > if (ret) { > err = ret; > diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c > index 1aee51a9f3bf..aac9b3ce5224 100644 > --- a/fs/btrfs/extent-tree.c > +++ b/fs/btrfs/extent-tree.c > @@ -10292,6 +10292,53 @@ static int check_chunk_block_group_mappings(struct btrfs_fs_info *fs_info) > return ret; > } > > +static int fill_dummy_bgs(struct btrfs_fs_info *fs_info) > +{ > + struct extent_map_tree *em_tree = &fs_info->mapping_tree.map_tree; > + struct extent_map *em; > + struct map_lookup *map; > + struct btrfs_block_group_cache *cache; > + struct btrfs_space_info *space_info; > + struct rb_node *node; > + int ret = 0; > + > + read_lock(&em_tree->lock); > + for (node = rb_first_cached(&em_tree->map); node; > + node = rb_next(node)) { > + em = rb_entry(node, struct extent_map, rb_node); > + map = em->map_lookup; > + cache = btrfs_create_block_group_cache(fs_info, em->start, > + em->len); > + if (!cache) { > + ret = -ENOMEM; > + goto out; > + } > + > + /* Fill dummy cache as FULL */ > + cache->flags = map->type; > + cache->last_byte_to_unpin = (u64)-1; > + cache->cached = BTRFS_CACHE_FINISHED; > + btrfs_set_block_group_used(&cache->item, em->len); > + btrfs_set_block_group_chunk_objectid(&cache->item, em->start); > + btrfs_set_block_group_flags(&cache->item, map->type); > + ret = btrfs_add_block_group_cache(fs_info, cache); > + if (ret) { > + btrfs_remove_free_space_cache(cache); > + btrfs_put_block_group(cache); > + goto out; > + } > + update_space_info(fs_info, cache->flags, em->len, em->len, > + 0, &space_info); > + cache->space_info = space_info; > + link_block_group(cache); > + > + set_avail_alloc_bits(fs_info, cache->flags); > + } > +out: > + read_unlock(&em_tree->lock); > + return ret; > +} > + > int btrfs_read_block_groups(struct btrfs_fs_info *info) > { > struct btrfs_path *path; > @@ -10306,6 +10353,9 @@ int btrfs_read_block_groups(struct btrfs_fs_info *info) > u64 feature; > int mixed; > > + if (btrfs_test_opt(info, SKIP_BG)) > + return fill_dummy_bgs(info); > + > feature = btrfs_super_incompat_flags(info->super_copy); > mixed = !!(feature & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS); > > diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c > index 4512f25dcf69..f9b33f175e02 100644 > --- a/fs/btrfs/super.c > +++ b/fs/btrfs/super.c > @@ -340,7 +340,7 @@ enum { > Opt_ref_verify, > #endif > /* Rescue options */ > - Opt_rescue, Opt_usebackuproot, Opt_nologreplay, > + Opt_rescue, Opt_usebackuproot, Opt_nologreplay, Opt_rescue_skip_bg, > Opt_err, > }; > > @@ -416,6 +416,7 @@ static const match_table_t tokens = { > static const match_table_t rescue_tokens = { > {Opt_usebackuproot, "use_backup_root"}, > {Opt_nologreplay, "no_log_replay"}, > + {Opt_rescue_skip_bg, "skip_bg"}, > {Opt_err, NULL}, > }; > > @@ -448,6 +449,10 @@ static int parse_rescue_options(struct btrfs_fs_info *info, const char *options) > btrfs_set_and_info(info, NOLOGREPLAY, > "disabling log replay at mount time"); > break; > + case Opt_rescue_skip_bg: > + btrfs_set_and_info(info, SKIP_BG, > + "skip mount time block group searching"); > + break; > case Opt_err: > btrfs_info(info, "unrecognized rescue option '%s'", p); > ret = -EINVAL; > @@ -1367,6 +1372,8 @@ static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry) > seq_puts(seq, ",notreelog"); > if (btrfs_test_opt(info, NOLOGREPLAY)) > seq_puts(seq, ",rescue=no_log_replay"); > + if (btrfs_test_opt(info, SKIP_BG)) > + seq_puts(seq, ",rescue=skip_bg"); Now that there are more possible values to print here, they need to follow the format with the separator.
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index 0a61dff27f57..9413db8c9bf0 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -1441,6 +1441,7 @@ static inline u32 BTRFS_MAX_XATTR_SIZE(const struct btrfs_fs_info *info) #define BTRFS_MOUNT_FREE_SPACE_TREE (1 << 26) #define BTRFS_MOUNT_NOLOGREPLAY (1 << 27) #define BTRFS_MOUNT_REF_VERIFY (1 << 28) +#define BTRFS_MOUNT_SKIP_BG (1 << 29) #define BTRFS_DEFAULT_COMMIT_INTERVAL (30) #define BTRFS_DEFAULT_MAX_INLINE (2048) diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index deb74a8c191a..9701bf8ffbda 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -2330,11 +2330,15 @@ static int btrfs_read_roots(struct btrfs_fs_info *fs_info) root = btrfs_read_tree_root(tree_root, &location); if (IS_ERR(root)) { - ret = PTR_ERR(root); - goto out; + if (!btrfs_test_opt(fs_info, SKIP_BG)) { + ret = PTR_ERR(root); + goto out; + } + fs_info->extent_root = NULL; + } else { + set_bit(BTRFS_ROOT_TRACK_DIRTY, &root->state); + fs_info->extent_root = root; } - set_bit(BTRFS_ROOT_TRACK_DIRTY, &root->state); - fs_info->extent_root = root; location.objectid = BTRFS_DEV_TREE_OBJECTID; root = btrfs_read_tree_root(tree_root, &location); @@ -2956,6 +2960,23 @@ int open_ctree(struct super_block *sb, goto fail_alloc; } + /* Skip bg needs RO and no log tree replay */ + if (btrfs_test_opt(fs_info, SKIP_BG)) { + if (!sb_rdonly(sb)) { + btrfs_err(fs_info, + "skip_bg mount option can only be used with read-only mount"); + err = -EINVAL; + goto fail_alloc; + } + if (btrfs_super_log_root(disk_super) && + !btrfs_test_opt(fs_info, NOTREELOG)) { + btrfs_err(fs_info, + "skip_bg must be used with notreelog mount option for dirty log"); + err = -EINVAL; + goto fail_alloc; + } + } + ret = btrfs_init_workqueues(fs_info, fs_devices); if (ret) { err = ret; diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index 1aee51a9f3bf..aac9b3ce5224 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -10292,6 +10292,53 @@ static int check_chunk_block_group_mappings(struct btrfs_fs_info *fs_info) return ret; } +static int fill_dummy_bgs(struct btrfs_fs_info *fs_info) +{ + struct extent_map_tree *em_tree = &fs_info->mapping_tree.map_tree; + struct extent_map *em; + struct map_lookup *map; + struct btrfs_block_group_cache *cache; + struct btrfs_space_info *space_info; + struct rb_node *node; + int ret = 0; + + read_lock(&em_tree->lock); + for (node = rb_first_cached(&em_tree->map); node; + node = rb_next(node)) { + em = rb_entry(node, struct extent_map, rb_node); + map = em->map_lookup; + cache = btrfs_create_block_group_cache(fs_info, em->start, + em->len); + if (!cache) { + ret = -ENOMEM; + goto out; + } + + /* Fill dummy cache as FULL */ + cache->flags = map->type; + cache->last_byte_to_unpin = (u64)-1; + cache->cached = BTRFS_CACHE_FINISHED; + btrfs_set_block_group_used(&cache->item, em->len); + btrfs_set_block_group_chunk_objectid(&cache->item, em->start); + btrfs_set_block_group_flags(&cache->item, map->type); + ret = btrfs_add_block_group_cache(fs_info, cache); + if (ret) { + btrfs_remove_free_space_cache(cache); + btrfs_put_block_group(cache); + goto out; + } + update_space_info(fs_info, cache->flags, em->len, em->len, + 0, &space_info); + cache->space_info = space_info; + link_block_group(cache); + + set_avail_alloc_bits(fs_info, cache->flags); + } +out: + read_unlock(&em_tree->lock); + return ret; +} + int btrfs_read_block_groups(struct btrfs_fs_info *info) { struct btrfs_path *path; @@ -10306,6 +10353,9 @@ int btrfs_read_block_groups(struct btrfs_fs_info *info) u64 feature; int mixed; + if (btrfs_test_opt(info, SKIP_BG)) + return fill_dummy_bgs(info); + feature = btrfs_super_incompat_flags(info->super_copy); mixed = !!(feature & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS); diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c index 4512f25dcf69..f9b33f175e02 100644 --- a/fs/btrfs/super.c +++ b/fs/btrfs/super.c @@ -340,7 +340,7 @@ enum { Opt_ref_verify, #endif /* Rescue options */ - Opt_rescue, Opt_usebackuproot, Opt_nologreplay, + Opt_rescue, Opt_usebackuproot, Opt_nologreplay, Opt_rescue_skip_bg, Opt_err, }; @@ -416,6 +416,7 @@ static const match_table_t tokens = { static const match_table_t rescue_tokens = { {Opt_usebackuproot, "use_backup_root"}, {Opt_nologreplay, "no_log_replay"}, + {Opt_rescue_skip_bg, "skip_bg"}, {Opt_err, NULL}, }; @@ -448,6 +449,10 @@ static int parse_rescue_options(struct btrfs_fs_info *info, const char *options) btrfs_set_and_info(info, NOLOGREPLAY, "disabling log replay at mount time"); break; + case Opt_rescue_skip_bg: + btrfs_set_and_info(info, SKIP_BG, + "skip mount time block group searching"); + break; case Opt_err: btrfs_info(info, "unrecognized rescue option '%s'", p); ret = -EINVAL; @@ -1367,6 +1372,8 @@ static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry) seq_puts(seq, ",notreelog"); if (btrfs_test_opt(info, NOLOGREPLAY)) seq_puts(seq, ",rescue=no_log_replay"); + if (btrfs_test_opt(info, SKIP_BG)) + seq_puts(seq, ",rescue=skip_bg"); if (btrfs_test_opt(info, FLUSHONCOMMIT)) seq_puts(seq, ",flushoncommit"); if (btrfs_test_opt(info, DISCARD)) @@ -1796,6 +1803,14 @@ static int btrfs_remount(struct super_block *sb, int *flags, char *data) if (ret) goto restore; + if (btrfs_test_opt(fs_info, SKIP_BG) != + (old_opts & BTRFS_MOUNT_SKIP_BG)) { + btrfs_err(fs_info, + "rescue=skip_bg mount option can't be changed during remount"); + ret = -EINVAL; + goto restore; + } + btrfs_remount_begin(fs_info, old_opts, *flags); btrfs_resize_thread_pool(fs_info, fs_info->thread_pool_size, old_thread_pool_size); @@ -1857,6 +1872,13 @@ static int btrfs_remount(struct super_block *sb, int *flags, char *data) goto restore; } + if (btrfs_test_opt(fs_info, SKIP_BG)) { + btrfs_err(fs_info, + "remounting read-write with rescue=skip_bg is not allowed"); + ret = -EINVAL; + goto restore; + } + ret = btrfs_cleanup_fs_roots(fs_info); if (ret) goto restore; diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index 1c2a6e4b39da..5d307b2b19d3 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -7740,6 +7740,13 @@ int btrfs_verify_dev_extents(struct btrfs_fs_info *fs_info) u64 prev_dev_ext_end = 0; int ret = 0; + /* + * For rescue=skip_bg mount option, we're already RO and are salvaging + * data, no need for such strict check. + */ + if (btrfs_test_opt(fs_info, SKIP_BG)) + return 0; + key.objectid = 1; key.type = BTRFS_DEV_EXTENT_KEY; key.offset = 0;
[PROBLEM] There are some reports of corrupted fs which can't be mounted due to corrupted extent tree. However under such situation, it's more likely the fs/subvolume trees are still fine. For such case we normally go btrfs-restore and salvage as much as we can. However btrfs-restore can't list subvolumes as "btrfs subv list", making it harder to restore a fs. [ENHANCEMENT] This patch will introduce a new mount option "rescue=skip_bg" to skip the mount time block group scan, and use chunk info purely to populate fake block group cache. The mount option has the following dependency: - RO mount Obviously. - No dirty log. Either there is no log, or use rescue=no_log_replay mount option. - No way to remoutn RW Similar to rescue=no_log_replay option. This should allow kernel to accept most extent tree corruption, and salvage data and subvolume info. Signed-off-by: Qu Wenruo <wqu@suse.com> --- fs/btrfs/ctree.h | 1 + fs/btrfs/disk-io.c | 29 ++++++++++++++++++++---- fs/btrfs/extent-tree.c | 50 ++++++++++++++++++++++++++++++++++++++++++ fs/btrfs/super.c | 24 +++++++++++++++++++- fs/btrfs/volumes.c | 7 ++++++ 5 files changed, 106 insertions(+), 5 deletions(-)