ocfs2: fix clusters leak in ocfs2_defrag_extent()

ocfs2_defrag_extent() might leak allocated clusters.  When the file
system has insufficient space, the number of claimed clusters might be
less than the caller wants.  If that happens, the original code might
directly commit the transaction without returning clusters.

This patch is based on code in ocfs2_add_clusters_in_btree().

[[email protected]: include localalloc.h, reduce scope of data_ac]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Larry Chen <[email protected]>
Reviewed-by: Andrew Morton <[email protected]>
Cc: Mark Fasheh <[email protected]>
Cc: Joel Becker <[email protected]>
Cc: Junxiao Bi <[email protected]>
Cc: Joseph Qi <[email protected]>
Cc: Changwei Ge <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

fs/ocfs2/move_extents.c

@@ -25,6 +25,7 @@
 #include "ocfs2_ioctl.h"
 
 #include "alloc.h"
+#include "localalloc.h"
 #include "aops.h"
 #include "dlmglue.h"
 #include "extent_map.h"
@@ -233,6 +234,7 @@ static int ocfs2_defrag_extent(struct ocfs2_move_extents_context *context,
 	struct ocfs2_refcount_tree *ref_tree = NULL;
 	u32 new_phys_cpos, new_len;
 	u64 phys_blkno = ocfs2_clusters_to_blocks(inode->i_sb, phys_cpos);
+	int need_free = 0;
 
 	if ((ext_flags & OCFS2_EXT_REFCOUNTED) && *len) {
 		BUG_ON(!ocfs2_is_refcount_inode(inode));
@@ -308,6 +310,7 @@ static int ocfs2_defrag_extent(struct ocfs2_move_extents_context *context,
 		if (!partial) {
 			context->range->me_flags &= ~OCFS2_MOVE_EXT_FL_COMPLETE;
 			ret = -ENOSPC;
+			need_free = 1;
 			goto out_commit;
 		}
 	}
@@ -332,6 +335,20 @@ static int ocfs2_defrag_extent(struct ocfs2_move_extents_context *context,
 		mlog_errno(ret);
 
 out_commit:
+	if (need_free && context->data_ac) {
+		struct ocfs2_alloc_context *data_ac = context->data_ac;
+
+		if (context->data_ac->ac_which == OCFS2_AC_USE_LOCAL)
+			ocfs2_free_local_alloc_bits(osb, handle, data_ac,
+					new_phys_cpos, new_len);
+		else
+			ocfs2_free_clusters(handle,
+					data_ac->ac_inode,
+					data_ac->ac_bh,
+					ocfs2_clusters_to_blocks(osb->sb, new_phys_cpos),
+					new_len);
+	}
+
 	ocfs2_commit_trans(osb, handle);
 
 out_unlock_mutex: