Re: filesystem dead, xfs_repair won't help

Avi Kivity
2017-04-11T11:40:19Z

On 04/11/2017 02:30 PM, Emmanuel Florac wrote:
> Le Tue, 11 Apr 2017 10:46:07 +0300
> Avi Kivity <avi@scylladb.com> écrivait:
>
>> $ sudo xfs_repair /dev/nvme0n1
>> Phase 1 - find and verify superblock...
>> couldn't verify primary superblock - not enough secondary superblocks
>> with matching geometry !!!
> Which version of xfs_repair is this?

xfsprogs-4.9.0-1.fc25.x86_64

> Try to export the FS structure with xfs_metadump, something like
>
> xfs_metadump /dev/nvme0n1 /some/file.dmp
>
> And check the errors it reports, they may be informative.

bad magic number
xfs_metadump: cannot read superblock for ag 1
bad magic number
xfs_metadump: cannot read superblock for ag 2
Metadata CRC error detected at xfs_agfl block 0x1dcf0963/0x200
bad magic number
xfs_metadump: cannot read superblock for ag 3
Metadata CRC error detected at xfs_agfl block 0x2cb68e13/0x200
xfs_metadump: Filesystem log is dirty; image will contain unobfuscated
metadata in log.
cache_purge: shake on cache 0x55accee162b0 left 3 nodes!?

> In the case where metadump works out fine, you should then try to have a
> look at the FS structure using the dump (to avoid wrecking it more that
> it already is):
>
> xfs_db -c "sb 0" /some/file.dmp
>

$ sudo xfs_db -c "sb 0" /tmp/fs
xfs_db: /tmp/fs is not a valid XFS filesystem (unexpected SB magic
number 0x5846534d)
Use -F to force a read attempt.
$ sudo xfs_db -F -c "sb 0" /tmp/fs
xfs_db: /tmp/fs is not a valid XFS filesystem (unexpected SB magic
number 0x5846534d)
xfs_db: V1 inodes unsupported. Please try an older xfsprogs.