1 files changed, 20 insertions, 3 deletions

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 7cf013349941..3351b1b24574 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -2220,6 +2220,12 @@ static noinline long btrfs_ioctl_clone(struct file *file, unsigned long srcfd,
             !IS_ALIGNED(destoff, bs))
                 goto out_unlock;
 
+        if (destoff > inode->i_size) {
+                ret = btrfs_cont_expand(inode, inode->i_size, destoff);
+                if (ret)
+                        goto out_unlock;
+        }
+
         /* do any pending delalloc/csum calc on src, one way or
            another, and lock file content */
         while (1) {
@@ -2236,6 +2242,10 @@ static noinline long btrfs_ioctl_clone(struct file *file, unsigned long srcfd,
                 btrfs_wait_ordered_range(src, off, len);
         }
 
+        /* truncate page cache pages from target inode range */
+        truncate_inode_pages_range(&inode->i_data, off,
+                                   ALIGN(off + len, PAGE_CACHE_SIZE) - 1);
+
         /* clone data */
         key.objectid = btrfs_ino(src);
         key.type = BTRFS_EXTENT_DATA_KEY;
@@ -2321,14 +2331,21 @@ static noinline long btrfs_ioctl_clone(struct file *file, unsigned long srcfd,
 
                         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,