xfs: store xfs_mount in the buftarg instead of in the xfs_buf

Each buffer contains both a buftarg pointer and a mount pointer. If
we add a mount pointer into the buftarg, we can avoid needing the
b_mount field in every buffer and grab it from the buftarg when
needed instead. This shrinks the xfs_buf by 8 bytes.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Alex Elder <aelder@sgi.com>

1 files changed, 7 insertions, 9 deletions

diff --git a/fs/xfs/xfs_log_recover.c b/fs/xfs/xfs_log_recover.c
index 3d887542b037..351d71117f16 100644
--- a/fs/xfs/xfs_log_recover.c
+++ b/fs/xfs/xfs_log_recover.c
@@ -322,10 +322,11 @@ xlog_recover_iodone(
                  * this during recovery. One strike!
                  */
                 xfs_ioerror_alert("xlog_recover_iodone",
-                                  bp->b_mount, bp, XFS_BUF_ADDR(bp));
-                xfs_force_shutdown(bp->b_mount, SHUTDOWN_META_IO_ERROR);
+                                        bp->b_target->bt_mount, bp,
+                                        XFS_BUF_ADDR(bp));
+                xfs_force_shutdown(bp->b_target->bt_mount,
+                                        SHUTDOWN_META_IO_ERROR);
         }
-        bp->b_mount = NULL;
         XFS_BUF_CLR_IODONE_FUNC(bp);
         xfs_biodone(bp);
 }
@@ -2276,8 +2277,7 @@ xlog_recover_do_buffer_trans(
                 XFS_BUF_STALE(bp);
                 error = xfs_bwrite(mp, bp);
         } else {
-                ASSERT(bp->b_mount == NULL || bp->b_mount == mp);
-                bp->b_mount = mp;
+                ASSERT(bp->b_target->bt_mount == mp);
                 XFS_BUF_SET_IODONE_FUNC(bp, xlog_recover_iodone);
                 xfs_bdwrite(mp, bp);
         }
@@ -2541,8 +2541,7 @@ xlog_recover_do_inode_trans(
         }
 
 write_inode_buffer:
-        ASSERT(bp->b_mount == NULL || bp->b_mount == mp);
-        bp->b_mount = mp;
+        ASSERT(bp->b_target->bt_mount == mp);
         XFS_BUF_SET_IODONE_FUNC(bp, xlog_recover_iodone);
         xfs_bdwrite(mp, bp);
 error:
@@ -2679,8 +2678,7 @@ xlog_recover_do_dquot_trans(
         memcpy(ddq, recddq, item->ri_buf[1].i_len);
 
         ASSERT(dq_f->qlf_size == 2);
-        ASSERT(bp->b_mount == NULL || bp->b_mount == mp);
-        bp->b_mount = mp;
+        ASSERT(bp->b_target->bt_mount == mp);
         XFS_BUF_SET_IODONE_FUNC(bp, xlog_recover_iodone);
         xfs_bdwrite(mp, bp);