Btrfs: set dead flag on the right root when destroying snapshot (c55bfa67) · Commits · 戴 / test

We were setting the BTRFS_ROOT_SUBVOL_DEAD flag on the root of the parent of our target snapshot, instead of setting it in the target snapshot's root. This is easy to observe by running the following scenario: mkfs.btrfs -f /dev/sdd mount /dev/sdd /mnt btrfs subvolume create /mnt/first_subvol btrfs subvolume snapshot -r /mnt /mnt/mysnap1 btrfs subvolume delete /mnt/first_subvol btrfs subvolume snapshot -r /mnt /mnt/mysnap2 btrfs send -p /mnt/mysnap1 /mnt/mysnap2 -f /tmp/send.data The send command failed because the send ioctl returned -EPERM. A test case for xfstests follows. Signed-off-by:

Filipe David Borba Manana <fdmanana@gmail.com> Reviewed-by:

David Sterba <dsterba@suse.cz> Signed-off-by:

Chris Mason <clm@fb.com>

fs/btrfs/ioctl.c

+6 −6

Original line number	Diff line number	Diff line
		@@ -2312,16 +2312,16 @@ static noinline int btrfs_ioctl_snap_destroy(struct file *file,
		* again is not run concurrently.
		*/
		spin_lock(&dest->root_item_lock);
		root_flags = btrfs_root_flags(&root->root_item);
		if (root->send_in_progress == 0) {
		btrfs_set_root_flags(&root->root_item,
		root_flags = btrfs_root_flags(&dest->root_item);
		if (dest->send_in_progress == 0) {
		btrfs_set_root_flags(&dest->root_item,
		root_flags \| BTRFS_ROOT_SUBVOL_DEAD);
		spin_unlock(&dest->root_item_lock);
		} else {
		spin_unlock(&dest->root_item_lock);
		btrfs_warn(root->fs_info,
		"Attempt to delete subvolume %llu during send",
		root->root_key.objectid);
		dest->root_key.objectid);
		err = -EPERM;
		goto out_dput;
		}
		@@ -2416,8 +2416,8 @@ out_up_write:
		out_unlock:
		if (err) {
		spin_lock(&dest->root_item_lock);
		root_flags = btrfs_root_flags(&root->root_item);
		btrfs_set_root_flags(&root->root_item,
		root_flags = btrfs_root_flags(&dest->root_item);
		btrfs_set_root_flags(&dest->root_item,
		root_flags & ~BTRFS_ROOT_SUBVOL_DEAD);
		spin_unlock(&dest->root_item_lock);
		}

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