diff options
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/xfs/xfs_mount.c | 37 | ||||
| -rw-r--r-- | fs/xfs/xfs_sb.h | 7 |
2 files changed, 29 insertions, 15 deletions
diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c index 4e93c02faf2..8ed164eb954 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( diff --git a/fs/xfs/xfs_sb.h b/fs/xfs/xfs_sb.h index b1a83f8ec04..d904efe7f87 100644 --- a/fs/xfs/xfs_sb.h +++ b/fs/xfs/xfs_sb.h @@ -320,11 +320,12 @@ static inline int xfs_sb_good_version(xfs_sb_t *sbp) #endif /* __KERNEL__ */ /* - * Detect a bad features2 field + * Detect a mismatched features2 field. Older kernels read/wrote + * this into the wrong slot, so to be safe we keep them in sync. */ -static inline int xfs_sb_has_bad_features2(xfs_sb_t *sbp) +static inline int xfs_sb_has_mismatched_features2(xfs_sb_t *sbp) { - return (sbp->sb_bad_features2 != 0); + return (sbp->sb_bad_features2 != sbp->sb_features2); } static inline unsigned xfs_sb_version_tonew(unsigned v) |