ocfs2: Try to free truncate log when meeting ENOSPC in write.

Recently, one of our colleagues meet with a problem that if we
write/delete a 32mb files repeatly, we will get an ENOSPC in
the end. And the corresponding bug is 1288.
http://oss.oracle.com/bugzilla/show_bug.cgi?id=1288

The real problem is that although we have freed the clusters,
they are in truncate log and they will be summed up so that
we can free them once in a whole.

So this patch just try to resolve it. In case we see -ENOSPC
in ocfs2_write_begin_no_lock, we will check whether the truncate
log has enough clusters for our need, if yes, we will try to
flush the truncate log at that point and try again. This method
is inspired by Mark Fasheh <mfasheh@suse.com>. Thanks.

Cc: Mark Fasheh <mfasheh@suse.com>
Signed-off-by: Tao Ma <tao.ma@oracle.com>
Signed-off-by: Joel Becker <joel.becker@oracle.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/fs/ocfs2/ocfs2.h b/fs/ocfs2/ocfs2.h
index 70dd3b1798f1..51cd6898e7f1 100644
--- a/fs/ocfs2/ocfs2.h
+++ b/fs/ocfs2/ocfs2.h
@@ -420,6 +420,11 @@ struct ocfs2_super
         struct inode                    *osb_tl_inode;
         struct buffer_head              *osb_tl_bh;
         struct delayed_work             osb_truncate_log_wq;
+        /*
+         * How many clusters in our truncate log.
+         * It must be protected by osb_tl_inode->i_mutex.
+         */
+        unsigned int truncated_clusters;
 
         struct ocfs2_node_map           osb_recovering_orphan_dirs;
         unsigned int                    *osb_orphan_wipes;