diff options
| author | Eric Sandeen <sandeen@sandeen.net> | 2008-04-10 12:19:34 +1000 |
|---|---|---|
| committer | Lachlan McIlroy <lachlan@redback.melbourne.sgi.com> | 2008-04-10 16:25:26 +1000 |
| commit | e6957ea48429aeda4f5d51af4238231d44b0dc4a (patch) | |
| tree | 860c95c0e9446191262bb44ad436d38afb8cb7d6 /fs/xfs/xfs_mount.c | |
| parent | ee1c090825bf2f1cb9712489c234eabf69a9a78f (diff) | |
[XFS] Ensure "both" features2 slots are consistent
Since older kernels may look in the sb_bad_features2 slot for flags,
rather than zeroing it out on fixup, we should make it equal to the
sb_features2 value.
Also, if the ATTR2 flag was not found prior to features2 fixup, it was not
set in the mount flags, so re-check after the fixup so that the current
session will use the feature.
Also fix up the comments to reflect these changes.
SGI-PV: 980085
SGI-Modid: xfs-linux-melb:xfs-kern:30778a
Signed-off-by: Eric Sandeen <sandeen@sandeen.net>
Signed-off-by: David Chinner <dgc@sgi.com>
Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>
Diffstat (limited to 'fs/xfs/xfs_mount.c')
| -rw-r--r-- | fs/xfs/xfs_mount.c | 37 |
1 files changed, 25 insertions, 12 deletions
diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c index 4e93c02faf24..8ed164eb9544 100644 --- a/fs/xfs/xfs_mount.c +++ b/fs/xfs/xfs_mount.c @@ -972,23 +972,35 @@ xfs_mountfs( xfs_mount_common(mp, sbp); /* - * Check for a bad features2 field alignment. This happened on - * some platforms due to xfs_sb_t not being 64bit size aligned - * when sb_features was added and hence the compiler put it in - * the wrong place. + * Check for a mismatched features2 values. Older kernels + * read & wrote into the wrong sb offset for sb_features2 + * on some platforms due to xfs_sb_t not being 64bit size aligned + * when sb_features2 was added, which made older superblock + * reading/writing routines swap it as a 64-bit value. * - * If we detect a bad field, we or the set bits into the existing - * features2 field in case it has already been modified and we - * don't want to lose any features. Zero the bad one and mark - * the two fields as needing updates once the transaction subsystem - * is online. + * For backwards compatibility, we make both slots equal. + * + * If we detect a mismatched field, we OR the set bits into the + * existing features2 field in case it has already been modified; we + * don't want to lose any features. We then update the bad location + * with the ORed value so that older kernels will see any features2 + * flags, and mark the two fields as needing updates once the + * transaction subsystem is online. */ - if (xfs_sb_has_bad_features2(sbp)) { + if (xfs_sb_has_mismatched_features2(sbp)) { cmn_err(CE_WARN, "XFS: correcting sb_features alignment problem"); sbp->sb_features2 |= sbp->sb_bad_features2; - sbp->sb_bad_features2 = 0; + sbp->sb_bad_features2 = sbp->sb_features2; update_flags |= XFS_SB_FEATURES2 | XFS_SB_BAD_FEATURES2; + + /* + * Re-check for ATTR2 in case it was found in bad_features2 + * slot. + */ + if (xfs_sb_version_hasattr2(&mp->m_sb)) + mp->m_flags |= XFS_MOUNT_ATTR2; + } /* @@ -1896,7 +1908,8 @@ xfs_uuid_unmount( /* * Used to log changes to the superblock unit and width fields which could - * be altered by the mount options. Only the first superblock is updated. + * be altered by the mount options, as well as any potential sb_features2 + * fixup. Only the first superblock is updated. */ STATIC void xfs_mount_log_sb( |