On Mon, 17 Jun 2013, Karol Jurak wrote: > On Friday 14 of June 2013 08:56:55 Sage Weil wrote: > > On Fri, 14 Jun 2013, Karol Jurak wrote: > > > I noticed that writing to RBD image using kernel driver while it's > > > snapshot is being created causes I/O errors and the filesystem > > > (reiserfs) eventually aborts and remounts itself in read-only mode: > > > > This is definitely a bug; you should be able to create a snapshot at any > > time. After a rollback, it should look (to the fs) like a crash or power > > cycle. > > > > How easy is this to reproduce? Does it happen every time? > > I can reproduce it in the following way: > > # rbd create -s 10240 test > # rbd map test > # mkfs -t reiserfs /dev/rbd/rbd/test > # mount /dev/rbd/rbd/test /mnt/test > # dd if=/dev/zero of=/mnt/test/a bs=1M count=1024 > > and in another shell while dd is running: > > # rbd snap create test@snap1 > > After 2 or 3 seconds dmesg shows I/O errors: > > [429532.259910] end_request: I/O error, dev rbd1, sector 1384448 > [429532.272554] end_request: I/O error, dev rbd1, sector 872 > [429532.275556] REISERFS abort (device rbd1): Journal write error in > flush_commit_list > > and dd fails: > > dd: writing `/mnt/test/a': Cannot allocate memory > 590+0 records in > 589+0 records out > 618225664 bytes (618 MB) copied, 15.8701 s, 39.0 MB/s > > This happens every time I repeat the test. What kernel version are you using? I'm not able to reproduce this with ext4 or reiserfs and many snapshots over several minutes of write workload. sage -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
