This patchset can be fetched from github: https://github.com/adam900710/linux/tree/rescue_options
There are quite some btrfs extent tree corruption report in the mail list. Since btrfs will do mount time block group item search, one corrupted leaf containing block group item will prevent the whole fs to be mounted. This patchset will try to address the problem by introducing a new mount option, "rescue=skip_bg", as a last-resort rescue. Of course this option will have a lot of restriction to prevent further screwing up the fs, including: - Permanent RO No remount rw is allowed - No dirty log Either clean the log or use rescue=no_log_replay mount option This "rescue=skip_bg" has some advantage compared to user space tool like "btrfs-restore": - Unified recovery tool User can use any tool they're familiar with, as long as the kernel doesn't panic. - More info for subvolume. "btrfs subv list" can word now! Although, move the following mount options to "rescue=" mount option: - nologreplay to rescue=no_log_replay - usebackuproot to rescue=use_backup_root Old options are still available for compatibility purpose, but they are deprecated in favor of new 'rescue=' super option. Also different rescue sub options can be separated by ':', like: "rescue=no_log_replay:skip_bg:use_backup_root". The separation character is chosen by: - No conflicts with existing character Especially no conflict with ','. - No extra escaping/quota Original plan is ';', but since it'll be interpreted by bash, it's changed to current ':'. Changelog: v2: - Introduce 'rescue=' super option. - Rename original 'usebackuproot' and 'nologreplay'. It at least makes my vim spell check happier. - Remove 'recovery' mount option. As its successor is now deprecated, not need to keep the predecessor. Qu Wenruo (3): btrfs: Remove "recovery" mount option btrfs: Introduce "rescue=" mount option btrfs: Introduce new mount option to skip block group items scan fs/btrfs/ctree.h | 1 + fs/btrfs/disk-io.c | 29 +++++++++++-- fs/btrfs/extent-tree.c | 59 ++++++++++++++++++++++++++ fs/btrfs/super.c | 96 ++++++++++++++++++++++++++++++++++++------ fs/btrfs/volumes.c | 7 +++ 5 files changed, 176 insertions(+), 16 deletions(-) -- 2.20.1
