xfs: Add a comment in xfs_log_sb()

Add a comment explaining why the sb_frextents are updated outside the
if (xfs_has_lazycount(mp) check even though it is a lazycounter.
RT groups are supported only in v5 filesystems which always have
lazycounter enabled - so putting it inside the if(xfs_has_lazycount(mp)
check is redundant.

Suggested-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nirjhar Roy (IBM) <nirjhar.roy.lists@gmail.com>
Signed-off-by: Carlos Maiolino <cem@kernel.org>

diff --git a/fs/xfs/libxfs/xfs_sb.c b/fs/xfs/libxfs/xfs_sb.c
index 38d16fe1f6d8b4525366752d1b94972374b8b532..47322adb7690599f7c25e591c8650f437ddd94dd 100644 (file)
--- a/fs/xfs/libxfs/xfs_sb.c
+++ b/fs/xfs/libxfs/xfs_sb.c
@@ -1347,6 +1347,9 @@ xfs_log_sb(
         * feature was introduced.  This counter can go negative due to the way
         * we handle nearly-lockless reservations, so we must use the _positive
         * variant here to avoid writing out nonsense frextents.
+        *
+        * RT groups are only supported on v5 file systems, which always
+        * have lazy SB counters.
         */
        if (xfs_has_rtgroups(mp) && !xfs_has_zoned(mp)) {
                mp->m_sb.sb_frextents =