trešd., 2021. g. 17. marts, plkst. 12:28 — lietotājs Qu Wenruo (<quwenruo.bt...@gmx.com>) rakstīja: > > > > On 2021/3/17 上午9:29, Dāvis Mosāns wrote: > > trešd., 2021. g. 17. marts, plkst. 03:18 — lietotājs Dāvis Mosāns > > (<davis...@gmail.com>) rakstīja: > >> > >> Currently if there's any corruption at all in extent tree > >> (eg. even single bit) then mounting will fail with: > >> "failed to read block groups: -5" (-EIO) > >> It happens because we immediately abort on first error when > >> searching in extent tree for block groups. > >> > >> Now with this patch if `ignorebadroots` option is specified > >> then we handle such case and continue by removing already > >> created block groups and creating dummy block groups. > >> > >> Signed-off-by: Dāvis Mosāns <davis...@gmail.com> > >> --- > >> fs/btrfs/block-group.c | 14 ++++++++++++++ > >> fs/btrfs/disk-io.c | 4 ++-- > >> fs/btrfs/disk-io.h | 2 ++ > >> 3 files changed, 18 insertions(+), 2 deletions(-) > >> > >> diff --git a/fs/btrfs/block-group.c b/fs/btrfs/block-group.c > >> index 48ebc106a606..827a977614b3 100644 > >> --- a/fs/btrfs/block-group.c > >> +++ b/fs/btrfs/block-group.c > >> @@ -2048,6 +2048,20 @@ int btrfs_read_block_groups(struct btrfs_fs_info > >> *info) > >> ret = check_chunk_block_group_mappings(info); > >> error: > >> btrfs_free_path(path); > >> + > >> + if (ret == -EIO && btrfs_test_opt(info, IGNOREBADROOTS)) { > >> + btrfs_put_block_group_cache(info); > >> + btrfs_stop_all_workers(info); > >> + btrfs_free_block_groups(info); > >> + ret = btrfs_init_workqueues(info, NULL); > >> + if (ret) > >> + return ret; > >> + ret = btrfs_init_space_info(info); > >> + if (ret) > >> + return ret; > >> + return fill_dummy_bgs(info); > > When we hit bad things in extent tree, we should ensure we're mounting > the fs RO, or we can't continue. > > And we should also refuse to mount back to RW if we hit such case, so > that we don't need anything complex, just ignore the whole extent tree > and create the dummy block groups. >
That's what we're doing here, `ignorebadroots` implies RO mount and without specifying it doesn't mount at all. > > > > This isn't that nice, but I don't really know how to properly clean up > > everything related to already created block groups so this was easiest > > way. It seems to work fine. > > But looks like need to do something about replay log aswell because if > > it's not disabled then it fails with: > > > > [ 1397.246869] BTRFS info (device sde): start tree-log replay > > [ 1398.218685] BTRFS warning (device sde): sde checksum verify failed > > on 21057127661568 wanted 0xd1506ed9 found 0x22ab750a level 0 > > [ 1398.218803] BTRFS warning (device sde): sde checksum verify failed > > on 21057127661568 wanted 0xd1506ed9 found 0x7dd54bb9 level 0 > > [ 1398.218813] BTRFS: error (device sde) in __btrfs_free_extent:3054: > > errno=-5 IO failure > > [ 1398.218828] BTRFS: error (device sde) in > > btrfs_run_delayed_refs:2124: errno=-5 IO failure > > [ 1398.219002] BTRFS: error (device sde) in btrfs_replay_log:2254: > > errno=-5 IO failure (Failed to recover log tree) > > [ 1398.229048] BTRFS error (device sde): open_ctree failed > > This is because we shouldn't allow to do anything write to the fs if we > have anything wrong in extent tree. > This is happening when mounting read-only. My assumption is that it only tries to replay in memory without writing anything to disk.