From: Liu Bo <bo.li.liu@oracle.com>
Date: Mon, 10 Mar 2014 10:56:07 +0000 (+0800)
Subject: Btrfs: fix a crash of clone with inline extents's split
X-Git-Tag: v3.15-rc1~23^2~23
X-Git-Url: http://git.cascardo.info/?p=cascardo%2Flinux.git;a=commitdiff_plain;h=00fdf13a2e9f313a044288aa59d3b8ec29ff904a

Btrfs: fix a crash of clone with inline extents's split

xfstests's btrfs/035 triggers a BUG_ON, which we use to detect the split
of inline extents in __btrfs_drop_extents().

For inline extents, we cannot duplicate another EXTENT_DATA item, because
it breaks the rule of inline extents, that is, 'start offset' needs to be 0.

We have set limitations for the source inode's compressed inline extents,
because it needs to decompress and recompress.  Now the destination inode's
inline extents also need similar limitations.

With this, xfstests btrfs/035 doesn't run into panic.

Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: Chris Mason <clm@fb.com>
---

diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index b2143b8c33c5..036f506cabd8 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -804,7 +804,10 @@ next_slot:
 		 */
 		if (start > key.offset && end < extent_end) {
 			BUG_ON(del_nr > 0);
-			BUG_ON(extent_type == BTRFS_FILE_EXTENT_INLINE);
+			if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
+				ret = -EINVAL;
+				break;
+			}
 
 			memcpy(&new_key, &key, sizeof(new_key));
 			new_key.offset = start;
@@ -847,7 +850,10 @@ next_slot:
 		 *      | -------- extent -------- |
 		 */
 		if (start <= key.offset && end < extent_end) {
-			BUG_ON(extent_type == BTRFS_FILE_EXTENT_INLINE);
+			if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
+				ret = -EINVAL;
+				break;
+			}
 
 			memcpy(&new_key, &key, sizeof(new_key));
 			new_key.offset = end;
@@ -870,7 +876,10 @@ next_slot:
 		 */
 		if (start > key.offset && end >= extent_end) {
 			BUG_ON(del_nr > 0);
-			BUG_ON(extent_type == BTRFS_FILE_EXTENT_INLINE);
+			if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
+				ret = -EINVAL;
+				break;
+			}
 
 			btrfs_set_file_extent_num_bytes(leaf, fi,
 							start - key.offset);
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 3ca313b138ca..6778fa3c6ed2 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -3087,8 +3087,9 @@ process_slot:
 							 new_key.offset + datal,
 							 1);
 				if (ret) {
-					btrfs_abort_transaction(trans, root,
-								ret);
+					if (ret != -EINVAL)
+						btrfs_abort_transaction(trans,
+								root, ret);
 					btrfs_end_transaction(trans, root);
 					goto out;
 				}
@@ -3246,8 +3247,9 @@ static noinline long btrfs_ioctl_clone(struct file *file, unsigned long srcfd,
 	 *   decompress into destination's address_space (the file offset
 	 *   may change, so source mapping won't do), then recompress (or
 	 *   otherwise reinsert) a subrange.
-	 * - allow ranges within the same file to be cloned (provided
-	 *   they don't overlap)?
+	 *
+	 * - split destination inode's inline extents.  The inline extents can
+	 *   be either compressed or non-compressed.
 	 */
 
 	/* the destination must be opened for writing */