Btrfs: calc file extent num_bytes correctly in file clone
num_bytes should be 4096 not 12288.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index b3d249d..028a4b8 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -2333,14 +2333,21 @@
if (type == BTRFS_FILE_EXTENT_REG ||
type == BTRFS_FILE_EXTENT_PREALLOC) {
+ /*
+ * a | --- range to clone ---| b
+ * | ------------- extent ------------- |
+ */
+
+ /* substract range b */
+ if (key.offset + datal > off + len)
+ datal = off + len - key.offset;
+
+ /* substract range a */
if (off > key.offset) {
datao += off - key.offset;
datal -= off - key.offset;
}
- if (key.offset + datal > off + len)
- datal = off + len - key.offset;
-
ret = btrfs_drop_extents(trans, inode,
new_key.offset,
new_key.offset + datal,