xfs: disallow LARP on old fses

Before enabling logged xattrs, make sure the filesystem is new enough
 that it actually supports log incompat features.
 
 This has been lightly tested with fstests.  Enjoy!
 
 Signed-off-by: Darrick J. Wong <djwong@kernel.org>
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Merge tag 'fix-larp-requirements-6.6_2023-09-12' of https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux into xfs-6.6-fixesA

xfs: disallow LARP on old fses

Before enabling logged xattrs, make sure the filesystem is new enough
that it actually supports log incompat features.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>

* tag 'fix-larp-requirements-6.6_2023-09-12' of https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux:
  xfs: require a relatively recent V5 filesystem for LARP mode
This commit is contained in:
Chandan Babu R 2023-09-13 10:33:27 +05:30
commit 6ebb6500e5

View file

@ -46,6 +46,17 @@ xfs_attr_grab_log_assist(
if (xfs_sb_version_haslogxattrs(&mp->m_sb))
return 0;
/*
* Check if the filesystem featureset is new enough to set this log
* incompat feature bit. Strictly speaking, the minimum requirement is
* a V5 filesystem for the superblock field, but we'll require rmap
* or reflink to avoid having to deal with really old kernels.
*/
if (!xfs_has_reflink(mp) && !xfs_has_rmapbt(mp)) {
error = -EOPNOTSUPP;
goto drop_incompat;
}
/* Enable log-assisted xattrs. */
error = xfs_add_incompat_log_feature(mp,
XFS_SB_FEAT_INCOMPAT_LOG_XATTRS);