[PATCH v3 17/19] xfs: avoid setting XFS_ILOG_CORE if i_version doesn't need incrementing

[Jeff Layton]

From: Jeff Layton <jlay...@redhat.com>

If XFS_ILOG_CORE is already set then go ahead and increment it.

Signed-off-by: Jeff Layton <jlay...@redhat.com>
---
 fs/xfs/xfs_trans_inode.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/fs/xfs/xfs_trans_inode.c b/fs/xfs/xfs_trans_inode.c
index 225544327c4f..4a89da4b6fe7 100644
--- a/fs/xfs/xfs_trans_inode.c
+++ b/fs/xfs/xfs_trans_inode.c
@@ -112,15 +112,17 @@ xfs_trans_log_inode(
 
        /*
         * First time we log the inode in a transaction, bump the inode change
-        * counter if it is configured for this to occur. We don't use
-        * inode_inc_version() because there is no need for extra locking around
-        * i_version as we already hold the inode locked exclusively for
-        * metadata modification.
+        * counter if it is configured for this to occur. While we have the
+        * inode locked exclusively for metadata modification, we can usually
+        * avoid setting XFS_ILOG_CORE if no one has queried the value since
+        * the last time it was incremented. If we have XFS_ILOG_CORE already
+        * set however, then go ahead and bump the i_version counter
+        * unconditionally.
         */
        if (!(ip->i_itemp->ili_item.li_desc->lid_flags & XFS_LID_DIRTY) &&
            IS_I_VERSION(VFS_I(ip))) {
-               inode_inc_iversion(VFS_I(ip));
-               flags |= XFS_ILOG_CORE;
+               if (inode_maybe_inc_iversion(VFS_I(ip), flags & XFS_ILOG_CORE))
+                       flags |= XFS_ILOG_CORE;
        }
 
        tp->t_flags |= XFS_TRANS_DIRTY;
-- 
2.14.3