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author | mav <mav@FreeBSD.org> | 2015-10-03 07:29:56 +0000 |
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committer | mav <mav@FreeBSD.org> | 2015-10-03 07:29:56 +0000 |
commit | 4a52577541ebbe34a9fa8abe3948a8514c63258c (patch) | |
tree | 8ed8ab1f80ef30fc8881b08dd4e4e6ea57f4f7c3 /sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dbuf.c | |
parent | 3529a708dddb3cca632de7b55ab67db8aa2f543d (diff) | |
download | FreeBSD-src-4a52577541ebbe34a9fa8abe3948a8514c63258c.zip FreeBSD-src-4a52577541ebbe34a9fa8abe3948a8514c63258c.tar.gz |
MFC r286575: 5056 ZFS deadlock on db_mtx and dn_holds
Reviewed by: Will Andrews <willa@spectralogic.com>
Reviewed by: Matt Ahrens <mahrens@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Approved by: Dan McDonald <danmcd@omniti.com>
Author: Justin Gibbs <justing@spectralogic.com>
illumos/illumos-gate@bc9014e6a81272073b9854d9f65dd59e18d18c35
Diffstat (limited to 'sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dbuf.c')
-rw-r--r-- | sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dbuf.c | 182 |
1 files changed, 132 insertions, 50 deletions
diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dbuf.c b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dbuf.c index 61ea2a3..79b6aed 100644 --- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dbuf.c +++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dbuf.c @@ -24,6 +24,7 @@ * Copyright (c) 2012, 2015 by Delphix. All rights reserved. * Copyright (c) 2013 by Saso Kiselkov. All rights reserved. * Copyright (c) 2013, Joyent, Inc. All rights reserved. + * Copyright (c) 2014 Spectra Logic Corporation, All rights reserved. */ #include <sys/zfs_context.h> @@ -54,10 +55,16 @@ static void dbuf_destroy(dmu_buf_impl_t *db); static boolean_t dbuf_undirty(dmu_buf_impl_t *db, dmu_tx_t *tx); static void dbuf_write(dbuf_dirty_record_t *dr, arc_buf_t *data, dmu_tx_t *tx); +#ifndef __lint +extern inline void dmu_buf_init_user(dmu_buf_user_t *dbu, + dmu_buf_evict_func_t *evict_func, dmu_buf_t **clear_on_evict_dbufp); +#endif /* ! __lint */ + /* * Global data structures and functions for the dbuf cache. */ static kmem_cache_t *dbuf_cache; +static taskq_t *dbu_evict_taskq; /* ARGSUSED */ static int @@ -231,17 +238,72 @@ dbuf_hash_remove(dmu_buf_impl_t *db) static arc_evict_func_t dbuf_do_evict; +typedef enum { + DBVU_EVICTING, + DBVU_NOT_EVICTING +} dbvu_verify_type_t; + +static void +dbuf_verify_user(dmu_buf_impl_t *db, dbvu_verify_type_t verify_type) +{ +#ifdef ZFS_DEBUG + int64_t holds; + + if (db->db_user == NULL) + return; + + /* Only data blocks support the attachment of user data. */ + ASSERT(db->db_level == 0); + + /* Clients must resolve a dbuf before attaching user data. */ + ASSERT(db->db.db_data != NULL); + ASSERT3U(db->db_state, ==, DB_CACHED); + + holds = refcount_count(&db->db_holds); + if (verify_type == DBVU_EVICTING) { + /* + * Immediate eviction occurs when holds == dirtycnt. + * For normal eviction buffers, holds is zero on + * eviction, except when dbuf_fix_old_data() calls + * dbuf_clear_data(). However, the hold count can grow + * during eviction even though db_mtx is held (see + * dmu_bonus_hold() for an example), so we can only + * test the generic invariant that holds >= dirtycnt. + */ + ASSERT3U(holds, >=, db->db_dirtycnt); + } else { + if (db->db_immediate_evict == TRUE) + ASSERT3U(holds, >=, db->db_dirtycnt); + else + ASSERT3U(holds, >, 0); + } +#endif +} + static void dbuf_evict_user(dmu_buf_impl_t *db) { + dmu_buf_user_t *dbu = db->db_user; + ASSERT(MUTEX_HELD(&db->db_mtx)); - if (db->db_level != 0 || db->db_evict_func == NULL) + if (dbu == NULL) return; - db->db_evict_func(&db->db, db->db_user_ptr); - db->db_user_ptr = NULL; - db->db_evict_func = NULL; + dbuf_verify_user(db, DBVU_EVICTING); + db->db_user = NULL; + +#ifdef ZFS_DEBUG + if (dbu->dbu_clear_on_evict_dbufp != NULL) + *dbu->dbu_clear_on_evict_dbufp = NULL; +#endif + + /* + * Invoke the callback from a taskq to avoid lock order reversals + * and limit stack depth. + */ + taskq_dispatch_ent(dbu_evict_taskq, dbu->dbu_evict_func, dbu, 0, + &dbu->dbu_tqent); } boolean_t @@ -302,6 +364,12 @@ retry: for (i = 0; i < DBUF_MUTEXES; i++) mutex_init(&h->hash_mutexes[i], NULL, MUTEX_DEFAULT, NULL); + + /* + * All entries are queued via taskq_dispatch_ent(), so min/maxalloc + * configuration is not required. + */ + dbu_evict_taskq = taskq_create("dbu_evict", 1, minclsyspri, 0, 0, 0); } void @@ -314,6 +382,7 @@ dbuf_fini(void) mutex_destroy(&h->hash_mutexes[i]); kmem_free(h->hash_table, (h->hash_table_mask + 1) * sizeof (void *)); kmem_cache_destroy(dbuf_cache); + taskq_destroy(dbu_evict_taskq); } /* @@ -431,21 +500,27 @@ dbuf_verify(dmu_buf_impl_t *db) #endif static void +dbuf_clear_data(dmu_buf_impl_t *db) +{ + ASSERT(MUTEX_HELD(&db->db_mtx)); + dbuf_evict_user(db); + db->db_buf = NULL; + db->db.db_data = NULL; + if (db->db_state != DB_NOFILL) + db->db_state = DB_UNCACHED; +} + +static void dbuf_set_data(dmu_buf_impl_t *db, arc_buf_t *buf) { ASSERT(MUTEX_HELD(&db->db_mtx)); + ASSERT(buf != NULL); + db->db_buf = buf; - if (buf != NULL) { - ASSERT(buf->b_data != NULL); - db->db.db_data = buf->b_data; - if (!arc_released(buf)) - arc_set_callback(buf, dbuf_do_evict, db); - } else { - dbuf_evict_user(db); - db->db.db_data = NULL; - if (db->db_state != DB_NOFILL) - db->db_state = DB_UNCACHED; - } + ASSERT(buf->b_data != NULL); + db->db.db_data = buf->b_data; + if (!arc_released(buf)) + arc_set_callback(buf, dbuf_do_evict, db); } /* @@ -467,7 +542,7 @@ dbuf_loan_arcbuf(dmu_buf_impl_t *db) } else { abuf = db->db_buf; arc_loan_inuse_buf(abuf, db); - dbuf_set_data(db, NULL); + dbuf_clear_data(db); mutex_exit(&db->db_mtx); } return (abuf); @@ -703,7 +778,7 @@ dbuf_noread(dmu_buf_impl_t *db) dbuf_set_data(db, arc_buf_alloc(spa, db->db.db_size, db, type)); db->db_state = DB_FILL; } else if (db->db_state == DB_NOFILL) { - dbuf_set_data(db, NULL); + dbuf_clear_data(db); } else { ASSERT3U(db->db_state, ==, DB_CACHED); } @@ -759,7 +834,7 @@ dbuf_fix_old_data(dmu_buf_impl_t *db, uint64_t txg) dr->dt.dl.dr_data = arc_buf_alloc(spa, size, db, type); bcopy(db->db.db_data, dr->dt.dl.dr_data->b_data, size); } else { - dbuf_set_data(db, NULL); + dbuf_clear_data(db); } } @@ -810,7 +885,8 @@ void dbuf_free_range(dnode_t *dn, uint64_t start_blkid, uint64_t end_blkid, dmu_tx_t *tx) { - dmu_buf_impl_t *db, *db_next, db_search; + dmu_buf_impl_t db_search; + dmu_buf_impl_t *db, *db_next; uint64_t txg = tx->tx_txg; avl_index_t where; @@ -1388,7 +1464,7 @@ dbuf_undirty(dmu_buf_impl_t *db, dmu_tx_t *tx) arc_buf_t *buf = db->db_buf; ASSERT(db->db_state == DB_NOFILL || arc_released(buf)); - dbuf_set_data(db, NULL); + dbuf_clear_data(db); VERIFY(arc_buf_remove_ref(buf, db)); dbuf_evict(db); return (B_TRUE); @@ -1728,8 +1804,7 @@ dbuf_create(dnode_t *dn, uint8_t level, uint64_t blkid, db->db_parent = parent; db->db_blkptr = blkptr; - db->db_user_ptr = NULL; - db->db_evict_func = NULL; + db->db_user = NULL; db->db_immediate_evict = 0; db->db_freed_in_flight = 0; @@ -2195,7 +2270,7 @@ dbuf_rele_and_unlock(dmu_buf_impl_t *db, void *tag) /* * This dbuf has anonymous data associated with it. */ - dbuf_set_data(db, NULL); + dbuf_clear_data(db); VERIFY(arc_buf_remove_ref(buf, db)); dbuf_evict(db); } else { @@ -2228,7 +2303,8 @@ dbuf_rele_and_unlock(dmu_buf_impl_t *db, void *tag) } else { dbuf_clear(db); } - } else if (arc_buf_eviction_needed(db->db_buf)) { + } else if (db->db_objset->os_evicting || + arc_buf_eviction_needed(db->db_buf)) { dbuf_clear(db); } else { mutex_exit(&db->db_mtx); @@ -2247,51 +2323,57 @@ dbuf_refcount(dmu_buf_impl_t *db) } void * -dmu_buf_set_user(dmu_buf_t *db_fake, void *user_ptr, - dmu_buf_evict_func_t *evict_func) +dmu_buf_replace_user(dmu_buf_t *db_fake, dmu_buf_user_t *old_user, + dmu_buf_user_t *new_user) { - return (dmu_buf_update_user(db_fake, NULL, user_ptr, evict_func)); + dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; + + mutex_enter(&db->db_mtx); + dbuf_verify_user(db, DBVU_NOT_EVICTING); + if (db->db_user == old_user) + db->db_user = new_user; + else + old_user = db->db_user; + dbuf_verify_user(db, DBVU_NOT_EVICTING); + mutex_exit(&db->db_mtx); + + return (old_user); } void * -dmu_buf_set_user_ie(dmu_buf_t *db_fake, void *user_ptr, - dmu_buf_evict_func_t *evict_func) +dmu_buf_set_user(dmu_buf_t *db_fake, dmu_buf_user_t *user) { - dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; - - db->db_immediate_evict = TRUE; - return (dmu_buf_update_user(db_fake, NULL, user_ptr, evict_func)); + return (dmu_buf_replace_user(db_fake, NULL, user)); } void * -dmu_buf_update_user(dmu_buf_t *db_fake, void *old_user_ptr, void *user_ptr, - dmu_buf_evict_func_t *evict_func) +dmu_buf_set_user_ie(dmu_buf_t *db_fake, dmu_buf_user_t *user) { dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; - ASSERT(db->db_level == 0); - - ASSERT((user_ptr == NULL) == (evict_func == NULL)); - - mutex_enter(&db->db_mtx); - if (db->db_user_ptr == old_user_ptr) { - db->db_user_ptr = user_ptr; - db->db_evict_func = evict_func; - } else { - old_user_ptr = db->db_user_ptr; - } + db->db_immediate_evict = TRUE; + return (dmu_buf_set_user(db_fake, user)); +} - mutex_exit(&db->db_mtx); - return (old_user_ptr); +void * +dmu_buf_remove_user(dmu_buf_t *db_fake, dmu_buf_user_t *user) +{ + return (dmu_buf_replace_user(db_fake, user, NULL)); } void * dmu_buf_get_user(dmu_buf_t *db_fake) { dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; - ASSERT(!refcount_is_zero(&db->db_holds)); - return (db->db_user_ptr); + dbuf_verify_user(db, DBVU_NOT_EVICTING); + return (db->db_user); +} + +void +dmu_buf_user_evict_wait() +{ + taskq_wait(dbu_evict_taskq); } boolean_t |