Merge tag 'for-4.20-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave...

[linux-block.git] / fs / btrfs / ioctl.c

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 3ca6943827ef88e536b2d6c924e7664a3ab835e7..802a628e9f7d7fe629a76e8d108b75c04ed4246e 100644 (file)
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -3488,6 +3488,8 @@ static int btrfs_extent_same_range(struct inode *src, u64 loff, u64 olen,
                        const u64 sz = BTRFS_I(src)->root->fs_info->sectorsize;
 
                        len = round_down(i_size_read(src), sz) - loff;
+                       if (len == 0)
+                               return 0;
                        olen = len;
                }
        }
@@ -4257,9 +4259,17 @@ static noinline int btrfs_clone_files(struct file *file, struct file *file_src,
                goto out_unlock;
        if (len == 0)
                olen = len = src->i_size - off;
-       /* if we extend to eof, continue to block boundary */
-       if (off + len == src->i_size)
+       /*
+        * If we extend to eof, continue to block boundary if and only if the
+        * destination end offset matches the destination file's size, otherwise
+        * we would be corrupting data by placing the eof block into the middle
+        * of a file.
+        */
+       if (off + len == src->i_size) {
+               if (!IS_ALIGNED(len, bs) && destoff + len < inode->i_size)
+                       goto out_unlock;
                len = ALIGN(src->i_size, bs) - off;
+       }
 
        if (len == 0) {
                ret = 0;