Pawel Jakub Dawidek wrote: > I had another one, can you analize it? > > lock order reversal: > 1st 0xc44b9b00 zfs:dbuf (zfs:dbuf) @ > /zoo/pjd/zfstest/sys/modules/zfs/../../contrib/opensolaris/uts/common/fs/zfs/dbuf.c:1644 > 2nd 0xc45be898 zfs:dbufs (zfs:dbufs) @ > /zoo/pjd/zfstest/sys/modules/zfs/../../contrib/opensolaris/uts/common/fs/zfs/dnode_sync.c:357 > KDB: stack backtrace: > db_trace_self_wrapper(c05ee0fe) at db_trace_self_wrapper+0x25 > kdb_backtrace(0,ffffffff,c065f538,c065f5b0,c061e82c,...) at kdb_backtrace+0x29 > witness_checkorder(c45be898,9,c4113f3c,165) at witness_checkorder+0x586 > _sx_xlock(c45be898,c4113f3c,165,c41249e0,0,...) at _sx_xlock+0x6e > dnode_evict_dbufs(c45be730,0,c4406b40,0,c45be730,...) at > dnode_evict_dbufs+0x39 > dmu_objset_evict_dbufs(e6258bd0,0,4,c397c000,c40d9918,...) at > dmu_objset_evict_dbufs+0x131 > dmu_objset_evict(c397c200,c397c000,c397c600,c397c200,e6258c04,...) at > dmu_objset_evict+0xb1 > dsl_dataset_evict(c44b9ac4,c397c200,e6258c1c,c40aed02,c44b9ac4,...) at > dsl_dataset_evict+0x4e > dbuf_evict_user(c44b9ac4,c40ab3ee,1,0,e6258c2c,...) at dbuf_evict_user+0x4e > dbuf_rele(c44b9ac4,c397c200,e6258c50,c40c7c5c,c397c200,...) at dbuf_rele+0x72 > dsl_dataset_sync(c397c200,c3bfea80,0,c397c200,e6258c54,...) at > dsl_dataset_sync+0x44 > dsl_pool_sync(c397c600,148,0,c061e82c,c397c6ac,...) at dsl_pool_sync+0x78 > spa_sync(c37ef000,148,0,149,0,...) at spa_sync+0x2a2 > txg_sync_thread(c397c600,e6258d38) at txg_sync_thread+0x1df > fork_exit(c40d9918,c397c600,e6258d38) at fork_exit+0xac > fork_trampoline() at fork_trampoline+0x8 > --- trap 0x1, eip = 0, esp = 0xe6258d6c, ebp = 0 --- > > The backtrace is from where lock order is different than the first > recorded. > I'm not sure, since your line numbers don't quite match up with mine, but I think this is a complaint about the dn_dbufs_mtx vs the db_mtx?
If so, in this case its OK. The db_mtx we grab in dbuf_rele() is the "parent" dbuf for the dataset we are evicting from dsl_dataset_evict(). So its not possible that any of the locks we attempt to grab in dnode_evict_dbufs() could cause a deadlock with it. -Mark
