>Number: 175897 >Category: kern >Synopsis: operations on readonly zpool hang >Confidential: no >Severity: serious >Priority: medium >Responsible: freebsd-bugs >State: open >Quarter: >Keywords: >Date-Required: >Class: sw-bug >Submitter-Id: current-users >Arrival-Date: Wed Feb 06 20:10:00 UTC 2013 >Closed-Date: >Last-Modified: >Originator: John Hein >Release: >Organization: >Environment:
recent 8-stable, 9-stable; noticed on both i386 & amd64 >Description: On 9-stable & 8-stable, zfs/zpool operations hang when trying to work on a readonly pool. I've tried 'zfs set mountpoint' and 'zfs scrub' (the latter accidentally during overnight run of periodic with daily_scrub_zfs_enable=yes). See also https://forums.freebsd.org/showthread.php?t=35505&highlight=readonly+zpool which mentions a panic. I didn't get a panic (yet). Use case when this was noticed: replace old pool with new, setting the new pool to have the old pool's mountpoint (to avoid changing all nfs clients). I think zfs should refuse the operation if readonly is a problem. What I really wanted was for the data to be readonly, but not the zfs metadata (i.e., "_mostly_ readonly"). But I can see how disallowing metadata ops on a readonly pool makes sense. >How-To-Repeat: cd /tmp dd if=/dev/zero bs=1m count=100 > ! z0 dd if=/dev/zero bs=1m count=100 > ! z1 sudo mdconfig -f z0 sudo mdconfig -f z1 sudo zpool create -m /tmp/ztmp ztmp mirror /dev/md0 /dev/md1 sudo zpool export ztmp sudo zpool import -o readonly=on ztmp sudo zfs set mountpoint=/tmp/ztmpnew ztmp ... hangs here In another window... % ps -ww -ax -o pid,ppid,%cpu,%mem,vsz,rss,wchan,stat,lstart,time,command | egrep 'zfs|PID' PID PPID %CPU %MEM VSZ RSS WCHAN STAT STARTED TIME COMMAND 45377 0 0.0 0.0 0 32 l2arc_fe DL Wed Feb 6 12:38:30 2013 0:00.01 [zfskern] 45674 1 0.0 0.3 44460 3256 select I Wed Feb 6 12:40:54 2013 0:00.01 sudo zfs set mountpoint=/tmp/z\ tmpnew ztmp 45687 45674 0.0 0.3 33488 3064 tx->tx_s D Wed Feb 6 12:40:54 2013 0:00.00 zfs set mountpoint=/tmp/ztmpne\ w ztmp % sudo procstat -k 45674 45687 PID TID COMM TDNAME KSTACK 45674 100106 sudo - mi_switch sleepq_catch_signals sleepq_wait_sig _cv_wait_sig seltdw\ ait kern_select sys_select amd64_syscall Xfast_syscall 45687 100098 zfs - mi_switch sleepq_wait _cv_wait txg_wait_synced dsl_sync_task_group\ _wait dsl_sync_task_do dsl_props_set zfs_set_prop_nvlist zfs_ioc_set_prop zfsdev_ioctl devfs_ioctl_f kern_ioctl s\ ys_ioctl amd64_syscall Xfast_syscall >Fix: >Release-Note: >Audit-Trail: >Unformatted: _______________________________________________ freebsd-bugs@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-bugs To unsubscribe, send any mail to "freebsd-bugs-unsubscr...@freebsd.org"
