xfs: fix xfs_get_extsz_hint behavior with realtime alwayscow files

Currently, we (ab)use xfs_get_extsz_hint so that it always returns a
nonzero value for realtime files.  This apparently was done to disable
delayed allocation for realtime files.

However, once we enable realtime reflink, we can also turn on the
alwayscow flag to force CoW writes to realtime files.  In this case, the
logic will incorrectly send the write through the delalloc write path.

Fix this by adjusting the logic slightly.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>

diff --git a/libxfs/xfs_bmap.c b/libxfs/xfs_bmap.c
index 64d0e8390ee6cb371ef9cdb17c04ec02aee16391..1438755aad103db2502808281da3b7a57772953e 100644 (file)
--- a/libxfs/xfs_bmap.c
+++ b/libxfs/xfs_bmap.c
@@ -6498,9 +6498,8 @@ xfs_get_extsz_hint(
         * No point in aligning allocations if we need to COW to actually
         * write to them.
         */
-       if (xfs_is_always_cow_inode(ip))
-               return 0;
-       if ((ip->i_diflags & XFS_DIFLAG_EXTSIZE) && ip->i_extsize)
+       if (!xfs_is_always_cow_inode(ip) &&
+           (ip->i_diflags & XFS_DIFLAG_EXTSIZE) && ip->i_extsize)
                return ip->i_extsize;
        if (XFS_IS_REALTIME_INODE(ip) &&
            ip->i_mount->m_sb.sb_rextsize > 1)