[RFC PATCH 6/8] xfs: Report atomic write min and max for buf io as well

[Ojaswin Mujoo]

Now that we can reliably perform a HW based single block buffered atomic
write for page size == blocksize, start advertising it in XFS.

Signed-off-by: Ojaswin Mujoo <ojas...@linux.ibm.com>
---
 fs/xfs/xfs_iops.c | 28 ++++++++++++++++++++--------
 1 file changed, 20 insertions(+), 8 deletions(-)

diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c
index f036c46b19c5..67d370947d95 100644
--- a/fs/xfs/xfs_iops.c
+++ b/fs/xfs/xfs_iops.c
@@ -604,9 +604,10 @@ xfs_get_atomic_write_min(
        struct xfs_inode        *ip,
        bool                    is_dio)
 {
-       if (is_dio) {
-               struct xfs_mount *mp = ip->i_mount;
+       struct xfs_mount *mp = ip->i_mount;
+       uint32_t bs = mp->m_sb.sb_blocksize;
 
+       if (is_dio) {
                /*
                 * If we can complete an atomic write via atomic out of place 
writes,
                 * then advertise a minimum size of one fsblock.  Without this
@@ -618,10 +619,15 @@ xfs_get_atomic_write_min(
                 */
                if (xfs_inode_can_hw_atomic_write(ip) ||
                    xfs_inode_can_sw_atomic_write(ip))
-                       return mp->m_sb.sb_blocksize;
+                       return bs;
        }
+       /*
+        * Buffered IO only supports hw single block atomic writes and bs == ps
+        * configurations.
+        */
+       if (xfs_inode_can_hw_atomic_write(ip) && bs == PAGE_SIZE)
+               return bs;
 
-       /* buffered IO not supported yet so return 0 right away */
        return 0;
 }
 
@@ -630,7 +636,8 @@ xfs_get_atomic_write_max(
        struct xfs_inode        *ip,
        bool                    is_dio)
 {
-       struct xfs_mount        *mp = ip->i_mount;
+       struct xfs_mount *mp = ip->i_mount;
+       uint32_t bs = mp->m_sb.sb_blocksize;
 
        if (is_dio) {
                /*
@@ -640,7 +647,7 @@ xfs_get_atomic_write_max(
                 */
                if (!xfs_inode_can_sw_atomic_write(ip)) {
                        if (xfs_inode_can_hw_atomic_write(ip))
-                               return mp->m_sb.sb_blocksize;
+                               return bs;
                        return 0;
                }
 
@@ -653,8 +660,13 @@ xfs_get_atomic_write_max(
                        return XFS_FSB_TO_B(mp, 
mp->m_groups[XG_TYPE_RTG].awu_max);
                return XFS_FSB_TO_B(mp, mp->m_groups[XG_TYPE_AG].awu_max);
        }
+       /*
+        * Buffered IO only supports hw single block atomic writes and bs == ps
+        * configurations.
+        */
+       if (xfs_inode_can_hw_atomic_write(ip) && bs == PAGE_SIZE)
+               return bs;
 
-       /* buffered IO not supported yet so return 0 right away */
        return 0;
 }
 
@@ -679,7 +691,7 @@ xfs_get_atomic_write_max_opt(
                return min(awu_max, xfs_inode_buftarg(ip)->bt_awu_max);
        }
 
-       /* buffered IO not supported yet so return 0 right away */
+       /* buffered IO for now only supports 1 filesyste block so max_opt is 0 
*/
        return 0;
 }
 
-- 
2.51.0