Brian Behlendorf 76351672c2 Fix zfsctl_expire_snapshot() deadlock ... It is possible for an automounted snapshot which is expiring to deadlock with a manual unmount of the snapshot. This can occur because taskq_cancel_id() will block if the task is currently executing until it completes. But it will never complete because zfsctl_unmount_snapshot() is holding the zsb->z_ctldir_lock which zfsctl_expire_snapshot() must acquire. ---------------------- z_unmount/0:2153 --------------------- mutex_lock <blocking on zsb->z_ctldir_lock> zfsctl_unmount_snapshot zfsctl_expire_snapshot taskq_thread ------------------------- zfs:10690 ------------------------- taskq_wait_id <waiting for z_unmount to exit> taskq_cancel_id __zfsctl_unmount_snapshot zfsctl_unmount_snapshot <takes zsb->z_ctldir_lock> zfs_unmount_snap zfs_ioc_destroy_snaps_nvl zfsdev_ioctl do_vfs_ioctl We resolve the deadlock by dropping the zsb->z_ctldir_lock before calling __zfsctl_unmount_snapshot(). The lock is only there to prevent concurrent modification to the zsb->z_ctldir_snaps AVL tree. Moreover, we're careful to remove the zfs_snapentry_t from the AVL tree before dropping the lock which ensures no other tasks can find it. On failure it's added back to the tree. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Chris Dunlap <cdunlap@llnl.gov> Closes #1527		2013-07-12 10:06:53 -07:00
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avl	Add script for builtin module building.	2012-07-26 13:45:09 -07:00
nvpair	Register correct handlers in nvlist_alloc()	2013-06-20 09:58:15 -07:00
unicode	Add script for builtin module building.	2012-07-26 13:45:09 -07:00
zcommon	Add snapdev=[hidden|visible] dataset property	2013-03-05 12:37:54 -08:00
zfs	Fix zfsctl_expire_snapshot() deadlock	2013-07-12 10:06:53 -07:00
zpios	Refresh links to web site	2013-03-06 15:46:41 -08:00
.gitignore	gitignore: anchor entries at their respective directory	2013-04-02 10:50:17 -07:00
Makefile.in	Add KMODDIR to install target	2013-03-06 15:46:40 -08:00