Commit 0e7b824c authored Sep 18, 2011 by Li Zefan Committed by Chris Mason Sep 18, 2011

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: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

parent 71ef0786

fs/btrfs/ioctl.c

+5 −0

Original line number	Original line	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))		if (!(src_file->f_mode & FMODE_READ))
	goto out_fput;		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;		ret = -EISDIR;
	if (S_ISDIR(src->i_mode) \|\| S_ISDIR(inode->i_mode))		if (S_ISDIR(src->i_mode) \|\| S_ISDIR(inode->i_mode))
	goto out_fput;		goto out_fput;

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