| From 86755b7a96faed57f910f9e6b8061e019ac1ec08 Mon Sep 17 00:00:00 2001 |
| From: Michael Lyle <mlyle@lyle.org> |
| Date: Mon, 5 Mar 2018 13:41:55 -0800 |
| Subject: bcache: don't attach backing with duplicate UUID |
| |
| From: Michael Lyle <mlyle@lyle.org> |
| |
| commit 86755b7a96faed57f910f9e6b8061e019ac1ec08 upstream. |
| |
| This can happen e.g. during disk cloning. |
| |
| This is an incomplete fix: it does not catch duplicate UUIDs earlier |
| when things are still unattached. It does not unregister the device. |
| Further changes to cope better with this are planned but conflict with |
| Coly's ongoing improvements to handling device errors. In the meantime, |
| one can manually stop the device after this has happened. |
| |
| Attempts to attach a duplicate device result in: |
| |
| [ 136.372404] loop: module loaded |
| [ 136.424461] bcache: register_bdev() registered backing device loop0 |
| [ 136.424464] bcache: bch_cached_dev_attach() Tried to attach loop0 but duplicate UUID already attached |
| |
| My test procedure is: |
| |
| dd if=/dev/sdb1 of=imgfile bs=1024 count=262144 |
| losetup -f imgfile |
| |
| Signed-off-by: Michael Lyle <mlyle@lyle.org> |
| Reviewed-by: Tang Junhui <tang.junhui@zte.com.cn> |
| Cc: <stable@vger.kernel.org> |
| Signed-off-by: Jens Axboe <axboe@kernel.dk> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| drivers/md/bcache/super.c | 11 +++++++++++ |
| 1 file changed, 11 insertions(+) |
| |
| --- a/drivers/md/bcache/super.c |
| +++ b/drivers/md/bcache/super.c |
| @@ -938,6 +938,7 @@ int bch_cached_dev_attach(struct cached_ |
| uint32_t rtime = cpu_to_le32(get_seconds()); |
| struct uuid_entry *u; |
| char buf[BDEVNAME_SIZE]; |
| + struct cached_dev *exist_dc, *t; |
| |
| bdevname(dc->bdev, buf); |
| |
| @@ -961,6 +962,16 @@ int bch_cached_dev_attach(struct cached_ |
| return -EINVAL; |
| } |
| |
| + /* Check whether already attached */ |
| + list_for_each_entry_safe(exist_dc, t, &c->cached_devs, list) { |
| + if (!memcmp(dc->sb.uuid, exist_dc->sb.uuid, 16)) { |
| + pr_err("Tried to attach %s but duplicate UUID already attached", |
| + buf); |
| + |
| + return -EINVAL; |
| + } |
| + } |
| + |
| u = uuid_find(c, dc->sb.uuid); |
| |
| if (u && |