[BUG]
There is a report that, btrfstune can even work while the fs has transid
mismatch problems.
$ btrfstune -f -u /dev/sdb1
Current fsid: b2b5ae8d-4c49-45f0-b42e-46fe7dcfcb07
New fsid: b2b5ae8d-4c49-45f0-b42e-46fe7dcfcb07
Set superblock flag CHANGING_FSID
Change fsid in extents
parent transid verify failed on 792854528 wanted 20103 found 20091
parent transid verify failed on 792854528 wanted 20103 found 20091
parent transid verify failed on 792854528 wanted 20103 found 20091
Ignoring transid failure
parent transid verify failed on 792870912 wanted 20103 found 20091
parent transid verify failed on 792870912 wanted 20103 found 20091
parent transid verify failed on 792870912 wanted 20103 found 20091
Ignoring transid failure
parent transid verify failed on 792887296 wanted 20103 found 20091
parent transid verify failed on 792887296 wanted 20103 found 20091
parent transid verify failed on 792887296 wanted 20103 found 20091
Ignoring transid failure
ERROR: child eb corrupted: parent bytenr=38010880 item=69 parent level=1 child level=1
ERROR: failed to change UUID of metadata: -5
ERROR: btrfstune failed
This leaves a corrupted fs even more corrupted, and due to the extra
CHANGING_FSID flag, btrfs check will not even try to run on it:
Opening filesystem to check...
ERROR: Filesystem UUID change in progress
ERROR: cannot open file system
[CAUSE]
Unlike kernel, btrfs-progs has a less strict check on transid mismatch.
In read_tree_block() we will fall back to use the tree block even its
transid mismatch if we can't find any better copy.
However not all commands in btrfs-progs needs this feature, only
btrfs-check (which may fix the problem) and btrfs-restore (it just tries
to ignore any problems) really utilize this feature.
[FIX]
Introduce a new open ctree flag, OPEN_CTREE_ALLOW_TRANSID_MISMATCH, to
be explicit about whether we really want to ignore transid error.
Currently only btrfs-check and btrfs-restore will utilize this new flag.
Also add btrfs-image to allow opening such fs with transid error.
Link: https://www.reddit.com/r/btrfs/comments/pivpqk/failure_during_btrfstune_u/
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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