X-Git-Url: https://git.camperquake.de/gitweb.cgi?a=blobdiff_plain;f=module%2Fzfs%2Fzvol.c;h=97b65c815e349d154d6963af33f83049d7e917f9;hb=2a3871d4bcc65dff7be4c9b55cb863421ddc8c3a;hp=5d4802560201cb839ac662a8927d6380f8958b0c;hpb=f74a147c022f79916e8525c2c16b1603f91202aa;p=zfs.git diff --git a/module/zfs/zvol.c b/module/zfs/zvol.c index 5d48025..97b65c8 100644 --- a/module/zfs/zvol.c +++ b/module/zfs/zvol.c @@ -141,6 +141,29 @@ zvol_find_by_name(const char *name) return NULL; } + +/* + * Given a path, return TRUE if path is a ZVOL. + */ +boolean_t +zvol_is_zvol(const char *device) +{ + struct block_device *bdev; + unsigned int major; + + bdev = lookup_bdev(device); + if (IS_ERR(bdev)) + return (B_FALSE); + + major = MAJOR(bdev->bd_dev); + bdput(bdev); + + if (major == zvol_major) + return (B_TRUE); + + return (B_FALSE); +} + /* * ZFS_IOC_CREATE callback handles dmu zvol and zap object creation. */ @@ -430,20 +453,20 @@ zvol_replay_err(zvol_state_t *zv, lr_t *lr, boolean_t byteswap) * Callback vectors for replaying records. * Only TX_WRITE is needed for zvol. */ -zil_replay_func_t *zvol_replay_vector[TX_MAX_TYPE] = { - (zil_replay_func_t *)zvol_replay_err, /* no such transaction type */ - (zil_replay_func_t *)zvol_replay_err, /* TX_CREATE */ - (zil_replay_func_t *)zvol_replay_err, /* TX_MKDIR */ - (zil_replay_func_t *)zvol_replay_err, /* TX_MKXATTR */ - (zil_replay_func_t *)zvol_replay_err, /* TX_SYMLINK */ - (zil_replay_func_t *)zvol_replay_err, /* TX_REMOVE */ - (zil_replay_func_t *)zvol_replay_err, /* TX_RMDIR */ - (zil_replay_func_t *)zvol_replay_err, /* TX_LINK */ - (zil_replay_func_t *)zvol_replay_err, /* TX_RENAME */ - (zil_replay_func_t *)zvol_replay_write, /* TX_WRITE */ - (zil_replay_func_t *)zvol_replay_err, /* TX_TRUNCATE */ - (zil_replay_func_t *)zvol_replay_err, /* TX_SETATTR */ - (zil_replay_func_t *)zvol_replay_err, /* TX_ACL */ +zil_replay_func_t zvol_replay_vector[TX_MAX_TYPE] = { + (zil_replay_func_t)zvol_replay_err, /* no such transaction type */ + (zil_replay_func_t)zvol_replay_err, /* TX_CREATE */ + (zil_replay_func_t)zvol_replay_err, /* TX_MKDIR */ + (zil_replay_func_t)zvol_replay_err, /* TX_MKXATTR */ + (zil_replay_func_t)zvol_replay_err, /* TX_SYMLINK */ + (zil_replay_func_t)zvol_replay_err, /* TX_REMOVE */ + (zil_replay_func_t)zvol_replay_err, /* TX_RMDIR */ + (zil_replay_func_t)zvol_replay_err, /* TX_LINK */ + (zil_replay_func_t)zvol_replay_err, /* TX_RENAME */ + (zil_replay_func_t)zvol_replay_write, /* TX_WRITE */ + (zil_replay_func_t)zvol_replay_err, /* TX_TRUNCATE */ + (zil_replay_func_t)zvol_replay_err, /* TX_SETATTR */ + (zil_replay_func_t)zvol_replay_err, /* TX_ACL */ }; /* @@ -868,25 +891,49 @@ zvol_first_open(zvol_state_t *zv) { objset_t *os; uint64_t volsize; + int locked = 0; int error; uint64_t ro; + /* + * In all other cases the spa_namespace_lock is taken before the + * bdev->bd_mutex lock. But in this case the Linux __blkdev_get() + * function calls fops->open() with the bdev->bd_mutex lock held. + * + * To avoid a potential lock inversion deadlock we preemptively + * try to take the spa_namespace_lock(). Normally it will not + * be contended and this is safe because spa_open_common() handles + * the case where the caller already holds the spa_namespace_lock. + * + * When it is contended we risk a lock inversion if we were to + * block waiting for the lock. Luckily, the __blkdev_get() + * function allows us to return -ERESTARTSYS which will result in + * bdev->bd_mutex being dropped, reacquired, and fops->open() being + * called again. This process can be repeated safely until both + * locks are acquired. + */ + if (!mutex_owned(&spa_namespace_lock)) { + locked = mutex_tryenter(&spa_namespace_lock); + if (!locked) + return (-ERESTARTSYS); + } + /* lie and say we're read-only */ error = dmu_objset_own(zv->zv_name, DMU_OST_ZVOL, 1, zvol_tag, &os); if (error) - return (-error); + goto out_mutex; error = zap_lookup(os, ZVOL_ZAP_OBJ, "size", 8, 1, &volsize); if (error) { - dmu_objset_disown(os, zvol_tag); - return (-error); + dmu_objset_disown(os, zvol_tag); + goto out_mutex; } zv->zv_objset = os; error = dmu_bonus_hold(os, ZVOL_OBJ, zvol_tag, &zv->zv_dbuf); if (error) { - dmu_objset_disown(os, zvol_tag); - return (-error); + dmu_objset_disown(os, zvol_tag); + goto out_mutex; } set_capacity(zv->zv_disk, volsize >> 9); @@ -894,14 +941,19 @@ zvol_first_open(zvol_state_t *zv) zv->zv_zilog = zil_open(os, zvol_get_data); VERIFY(dsl_prop_get_integer(zv->zv_name, "readonly", &ro, NULL) == 0); - if (ro || dmu_objset_is_snapshot(os)) { - set_disk_ro(zv->zv_disk, 1); - zv->zv_flags |= ZVOL_RDONLY; + if (ro || dmu_objset_is_snapshot(os) || + !spa_writeable(dmu_objset_spa(os))) { + set_disk_ro(zv->zv_disk, 1); + zv->zv_flags |= ZVOL_RDONLY; } else { - set_disk_ro(zv->zv_disk, 0); - zv->zv_flags &= ~ZVOL_RDONLY; + set_disk_ro(zv->zv_disk, 0); + zv->zv_flags &= ~ZVOL_RDONLY; } +out_mutex: + if (locked) + mutex_exit(&spa_namespace_lock); + return (-error); } @@ -1162,8 +1214,9 @@ zvol_alloc(dev_t dev, const char *name) int error = 0; zv = kmem_zalloc(sizeof (zvol_state_t), KM_SLEEP); - if (zv == NULL) - goto out; + + spin_lock_init(&zv->zv_lock); + list_link_init(&zv->zv_next); zv->zv_queue = blk_init_queue(zvol_request, &zv->zv_lock); if (zv->zv_queue == NULL) @@ -1198,9 +1251,6 @@ zvol_alloc(dev_t dev, const char *name) sizeof (rl_t), offsetof(rl_t, r_node)); zv->zv_znode.z_is_zvol = TRUE; - spin_lock_init(&zv->zv_lock); - list_link_init(&zv->zv_next); - zv->zv_disk->major = zvol_major; zv->zv_disk->first_minor = (dev & MINORMASK); zv->zv_disk->fops = &zvol_ops; @@ -1215,7 +1265,7 @@ out_queue: blk_cleanup_queue(zv->zv_queue); out_kmem: kmem_free(zv, sizeof (zvol_state_t)); -out: + return NULL; } @@ -1236,7 +1286,28 @@ zvol_free(zvol_state_t *zv) } static int -__zvol_create_minor(const char *name) +__zvol_snapdev_hidden(const char *name) +{ + uint64_t snapdev; + char *parent; + char *atp; + int error = 0; + + parent = kmem_alloc(MAXPATHLEN, KM_SLEEP); + (void) strlcpy(parent, name, MAXPATHLEN); + + if ((atp = strrchr(parent, '@')) != NULL) { + *atp = '\0'; + error = dsl_prop_get_integer(parent, "snapdev", &snapdev, NULL); + if ((error == 0) && (snapdev == ZFS_SNAPDEV_HIDDEN)) + error = ENODEV; + } + kmem_free(parent, MAXPATHLEN); + return (error); +} + +static int +__zvol_create_minor(const char *name, boolean_t ignore_snapdev) { zvol_state_t *zv; objset_t *os; @@ -1253,6 +1324,12 @@ __zvol_create_minor(const char *name) goto out; } + if (ignore_snapdev == B_FALSE) { + error = __zvol_snapdev_hidden(name); + if (error) + goto out; + } + doi = kmem_alloc(sizeof(dmu_object_info_t), KM_SLEEP); error = dmu_objset_own(name, DMU_OST_ZVOL, B_TRUE, zvol_tag, &os); @@ -1301,10 +1378,12 @@ __zvol_create_minor(const char *name) queue_flag_set_unlocked(QUEUE_FLAG_NONROT, zv->zv_queue); #endif - if (zil_replay_disable) - zil_destroy(dmu_objset_zil(os), B_FALSE); - else - zil_replay(os, zv, zvol_replay_vector); + if (spa_writeable(dmu_objset_spa(os))) { + if (zil_replay_disable) + zil_destroy(dmu_objset_zil(os), B_FALSE); + else + zil_replay(os, zv, zvol_replay_vector); + } zv->zv_objset = NULL; out_dmu_objset_disown: @@ -1332,7 +1411,7 @@ zvol_create_minor(const char *name) int error; mutex_enter(&zvol_state_lock); - error = __zvol_create_minor(name); + error = __zvol_create_minor(name, B_FALSE); mutex_exit(&zvol_state_lock); return (error); @@ -1380,7 +1459,7 @@ zvol_create_minors_cb(spa_t *spa, uint64_t dsobj, if (strchr(dsname, '/') == NULL) return 0; - (void) __zvol_create_minor(dsname); + (void) __zvol_create_minor(dsname, B_FALSE); return (0); } @@ -1448,35 +1527,72 @@ zvol_remove_minors(const char *pool) kmem_free(str, MAXNAMELEN); } +static int +snapdev_snapshot_changed_cb(const char *dsname, void *arg) { + uint64_t snapdev = *(uint64_t *) arg; + + if (strchr(dsname, '@') == NULL) + return 0; + + switch (snapdev) { + case ZFS_SNAPDEV_VISIBLE: + mutex_enter(&zvol_state_lock); + (void) __zvol_create_minor(dsname, B_TRUE); + mutex_exit(&zvol_state_lock); + break; + case ZFS_SNAPDEV_HIDDEN: + (void) zvol_remove_minor(dsname); + break; + } + return 0; +} + +int +zvol_set_snapdev(const char *dsname, uint64_t snapdev) { + (void) dmu_objset_find((char *) dsname, snapdev_snapshot_changed_cb, + &snapdev, DS_FIND_SNAPSHOTS | DS_FIND_CHILDREN); + /* caller should continue to modify snapdev property */ + return (-1); +} + + int zvol_init(void) { int error; + list_create(&zvol_state_list, sizeof (zvol_state_t), + offsetof(zvol_state_t, zv_next)); + mutex_init(&zvol_state_lock, NULL, MUTEX_DEFAULT, NULL); + zvol_taskq = taskq_create(ZVOL_DRIVER, zvol_threads, maxclsyspri, zvol_threads, INT_MAX, TASKQ_PREPOPULATE); if (zvol_taskq == NULL) { printk(KERN_INFO "ZFS: taskq_create() failed\n"); - return (-ENOMEM); + error = -ENOMEM; + goto out1; } error = register_blkdev(zvol_major, ZVOL_DRIVER); if (error) { printk(KERN_INFO "ZFS: register_blkdev() failed %d\n", error); - taskq_destroy(zvol_taskq); - return (error); + goto out2; } blk_register_region(MKDEV(zvol_major, 0), 1UL << MINORBITS, THIS_MODULE, zvol_probe, NULL, NULL); - mutex_init(&zvol_state_lock, NULL, MUTEX_DEFAULT, NULL); - list_create(&zvol_state_list, sizeof (zvol_state_t), - offsetof(zvol_state_t, zv_next)); - (void) zvol_create_minors(NULL); return (0); + +out2: + taskq_destroy(zvol_taskq); +out1: + mutex_destroy(&zvol_state_lock); + list_destroy(&zvol_state_list); + + return (error); } void