Ocfs2/move_extents: Set several trivial constraints for threshold.

The threshold should be greater than clustersize and less than i_size.

Signed-off-by: Tristan Ye <tristan.ye@oracle.com>

1 files changed, 17 insertions, 7 deletions

diff --git a/fs/ocfs2/move_extents.c b/fs/ocfs2/move_extents.c
index efc509b3af1f..4c5488468c14 100644
--- a/fs/ocfs2/move_extents.c
+++ b/fs/ocfs2/move_extents.c
@@ -220,6 +220,9 @@ out:
 /*
  * Using one journal handle to guarantee the data consistency in case
  * crash happens anywhere.
+ *
+ *  XXX: defrag can end up with finishing partial extent as requested,
+ * due to not enough contiguous clusters can be found in allocator.
  */
 static int ocfs2_defrag_extent(struct ocfs2_move_extents_context *context,
                                u32 cpos, u32 phys_cpos, u32 *len, int ext_flags)
@@ -876,9 +879,11 @@ static int __ocfs2_move_extents_range(struct buffer_head *di_bh,
         else
                 len_to_move = 0;
 
-        if (do_defrag)
+        if (do_defrag) {
                 defrag_thresh = range->me_threshold >> osb->s_clustersize_bits;
-        else
+                if (defrag_thresh <= 1)
+                        goto done;
+        } else
                 new_phys_cpos = ocfs2_blocks_to_clusters(inode->i_sb,
                                                          range->me_goal);
 
@@ -950,6 +955,7 @@ next:
                 len_to_move -= alloc_size;
         }
 
+done:
         range->me_flags |= OCFS2_MOVE_EXT_FL_COMPLETE;
 
 out:
@@ -1098,13 +1104,17 @@ int ocfs2_ioctl_move_extents(struct file *filp, void __user *argp)
 
         if (range.me_flags & OCFS2_MOVE_EXT_FL_AUTO_DEFRAG) {
                 context->auto_defrag = 1;
+                /*
+                 * ok, the default theshold for the defragmentation
+                 * is 1M, since our maximum clustersize was 1M also.
+                 * any thought?
+                 */
                 if (!range.me_threshold)
-                        /*
-                         * ok, the default theshold for the defragmentation
-                         * is 1M, since our maximum clustersize was 1M also.
-                         * any thought?
-                         */
                         range.me_threshold = 1024 * 1024;
+
+                if (range.me_threshold > i_size_read(inode))
+                        range.me_threshold = i_size_read(inode);
+
                 if (range.me_flags & OCFS2_MOVE_EXT_FL_PART_DEFRAG)
                         context->partial = 1;
         } else {