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().

[akpm@linux-foundation.org: include localalloc.h, reduce scope of data_ac]
Link: http://lkml.kernel.org/r/20180904041621.16874-3-lchen@suse.com
Signed-off-by: Larry Chen <lchen@suse.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Joseph Qi <jiangqi903@gmail.com>
Cc: Changwei Ge <ge.changwei@h3c.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

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: