[GFS2] Clean up gfs2_trans_add_revoke()

The following alters gfs2_trans_add_revoke() to take a struct
gfs2_bufdata as an argument. This eliminates the memory allocation which
was previously required by making use of the already existing struct
gfs2_bufdata. It makes some sanity checks to ensure that the
gfs2_bufdata has been removed from all the lists before its recycled as
a revoke structure. This saves one memory allocation and one free per
revoke structure.

Also as a result, and to simplify the locking, since there is no longer
any blocking code in gfs2_trans_add_revoke() we must hold the log lock
whenever this function is called. This reduces the amount of times we
take and unlock the log lock.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

1 files changed, 5 insertions, 9 deletions

diff --git a/fs/gfs2/glops.c b/fs/gfs2/glops.c
index b17346a355bf..4670dcb2a877 100644
--- a/fs/gfs2/glops.c
+++ b/fs/gfs2/glops.c
@@ -41,7 +41,6 @@ static void gfs2_ail_empty_gl(struct gfs2_glock *gl)
         struct list_head *head = &gl->gl_ail_list;
         struct gfs2_bufdata *bd;
         struct buffer_head *bh;
-        u64 blkno;
         int error;
 
         blocks = atomic_read(&gl->gl_ail_count);
@@ -57,15 +56,12 @@ static void gfs2_ail_empty_gl(struct gfs2_glock *gl)
                 bd = list_entry(head->next, struct gfs2_bufdata,
                                 bd_ail_gl_list);
                 bh = bd->bd_bh;
-                blkno = bh->b_blocknr;
-                gfs2_assert_withdraw(sdp, !buffer_busy(bh));
-
                 gfs2_remove_from_ail(NULL, bd);
-                gfs2_log_unlock(sdp);
-
-                gfs2_trans_add_revoke(sdp, blkno);
-
-                gfs2_log_lock(sdp);
+                bd->bd_bh = NULL;
+                bh->b_private = NULL;
+                bd->bd_blkno = bh->b_blocknr;
+                gfs2_assert_withdraw(sdp, !buffer_busy(bh));
+                gfs2_trans_add_revoke(sdp, bd);
         }
         gfs2_assert_withdraw(sdp, !atomic_read(&gl->gl_ail_count));
         gfs2_log_unlock(sdp);