From 074e427ba7f7398427e4f8e2aec071edcc509673 Mon Sep 17 00:00:00 2001 From: Dave Chinner Date: Thu, 22 Jan 2015 09:10:33 +1100 Subject: xfs: sanitise sb_bad_features2 handling We currently have to ensure that every time we update sb_features2 that we update sb_bad_features2. Now that we log and format the superblock in it's entirety we actually don't have to care because we can simply update the sb_bad_features2 when we format it into the buffer. This removes the need for anything but the mount and superblock formatting code to care about sb_bad_features2, and hence removes the possibility that we forget to update bad_features2 when necessary in the future. Signed-off-by: Dave Chinner Reviewed-by: Brian Foster Signed-off-by: Dave Chinner --- fs/xfs/xfs_mount.c | 23 +++++++++++------------ 1 file changed, 11 insertions(+), 12 deletions(-) (limited to 'fs/xfs/xfs_mount.c') diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c index 5ef9aa2bfa19..4fa80e63eea2 100644 --- a/fs/xfs/xfs_mount.c +++ b/fs/xfs/xfs_mount.c @@ -640,25 +640,24 @@ xfs_mountfs( xfs_sb_mount_common(mp, sbp); /* - * 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. + * 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. * * 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 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. The + * superblock writeback code ensures the new sb_features2 is copied to + * sb_bad_features2 before it is logged or written to disk. */ if (xfs_sb_has_mismatched_features2(sbp)) { xfs_warn(mp, "correcting sb_features alignment problem"); sbp->sb_features2 |= sbp->sb_bad_features2; - sbp->sb_bad_features2 = sbp->sb_features2; mp->m_update_sb = true; /* -- cgit v1.2.3