gfs2: Get rid of sd_reserving_log

This counter and the associated wait queue are only used so that
gfs2_make_fs_ro can efficiently wait for all pending log space
allocations to fail after setting the filesystem to read-only.  This
comes at the cost of waking up that wait queue very frequently.

Instead, when gfs2_log_reserve fails because the filesystem has become
read-only, Wake up sd_log_waitq.  In gfs2_make_fs_ro, set the file
system read-only and then wait until all the log space has been
released.  Give up and report the problem after a while.  With that,
sd_reserving_log and sd_reserving_log_wait can be removed.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

1 files changed, 10 insertions, 7 deletions

diff --git a/fs/gfs2/log.c b/fs/gfs2/log.c
index 0fceb60907a2..0da05492e8b8 100644
--- a/fs/gfs2/log.c
+++ b/fs/gfs2/log.c
@@ -398,6 +398,15 @@ static void ail2_empty(struct gfs2_sbd *sdp, unsigned int new_tail)
 }
 
 /**
+ * gfs2_log_is_empty - Check if the log is empty
+ * @sdp: The GFS2 superblock
+ */
+
+bool gfs2_log_is_empty(struct gfs2_sbd *sdp) {
+	return atomic_read(&sdp->sd_log_blks_free) == sdp->sd_jdesc->jd_blocks;
+}
+
+/**
  * gfs2_log_release - Release a given number of log blocks
  * @sdp: The GFS2 superblock
  * @blks: The number of blocks
@@ -461,13 +470,9 @@ retry:
 		} while(free_blocks <= wanted);
 		finish_wait(&sdp->sd_log_waitq, &wait);
 	}
-	atomic_inc(&sdp->sd_reserving_log);
 	if (atomic_cmpxchg(&sdp->sd_log_blks_free, free_blocks,
-				free_blocks - blks) != free_blocks) {
-		if (atomic_dec_and_test(&sdp->sd_reserving_log))
-			wake_up(&sdp->sd_reserving_log_wait);
+				free_blocks - blks) != free_blocks)
 		goto retry;
-	}
 	atomic_sub(blks, &sdp->sd_log_blks_needed);
 	trace_gfs2_log_blocks(sdp, -blks);
 
@@ -483,8 +488,6 @@ retry:
 		gfs2_log_release(sdp, blks);
 		ret = -EROFS;
 	}
-	if (atomic_dec_and_test(&sdp->sd_reserving_log))
-		wake_up(&sdp->sd_reserving_log_wait);
 	return ret;
 }