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Commit 0e7b824c authored by Li Zefan's avatar Li Zefan Committed by Chris Mason
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Btrfs: don't make a file partly checksummed through file clone 



To reproduce the bug:

  # mount /dev/sda7 /mnt
  # dd if=/dev/zero of=/mnt/src bs=4K count=1
  # umount /mnt

  # mount -o nodatasum /dev/sda7 /mnt
  # dd if=/dev/zero of=/mnt/dst bs=4K count=1
  # clone_range -s 4K -l 4K /mnt/src /mnt/dst

  # echo 3 > /proc/sys/vm/drop_caches
  # cat /mnt/dst
  # dmesg
  ...
  btrfs no csum found for inode 258 start 0
  btrfs csum failed ino 258 off 0 csum 2566472073 private 0

It's because part of the file is checksummed and the other part is not,
and then btrfs will complain checksum is not found when we read the file.

Disallow file clone if src and dst file have different checksum flag,
so we ensure a file is completely checksummed or unchecksummed.

Signed-off-by: default avatarLi Zefan <lizf@cn.fujitsu.com>
Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>
parent 71ef0786

fs/btrfs/ioctl.c

+5 −0
Original line number Diff line number Diff line
@@ -2185,6 +2185,11 @@ static noinline long btrfs_ioctl_clone(struct file *file, unsigned long srcfd, 
	if (!(src_file->f_mode & FMODE_READ))

		goto out_fput;



	/* don't make the dst file partly checksummed */

	if ((BTRFS_I(src)->flags & BTRFS_INODE_NODATASUM) !=

	    (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM))

		goto out_fput;



	ret = -EISDIR;

	if (S_ISDIR(src->i_mode) || S_ISDIR(inode->i_mode))

		goto out_fput;