#include <sys/zvol.h>
#include <linux/blkdev_compat.h>
+unsigned int zvol_inhibit_dev = 0;
unsigned int zvol_major = ZVOL_MAJOR;
unsigned int zvol_threads = 32;
+unsigned long zvol_max_discard_blocks = 16384;
static taskq_t *zvol_taskq;
static kmutex_t zvol_state_lock;
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.
*/
* 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 */
};
/*
dmu_tx_t *tx;
rl_t *rl;
+ /*
+ * Annotate this call path with a flag that indicates that it is
+ * unsafe to use KM_SLEEP during memory allocations due to the
+ * potential for a deadlock. KM_PUSHPAGE should be used instead.
+ */
+ ASSERT(!(current->flags & PF_NOFS));
+ current->flags |= PF_NOFS;
+
if (req->cmd_flags & VDEV_REQ_FLUSH)
zil_commit(zv->zv_zilog, ZVOL_OBJ);
*/
if (size == 0) {
blk_end_request(req, 0, size);
- return;
+ goto out;
}
rl = zfs_range_lock(&zv->zv_znode, offset, size, RL_WRITER);
dmu_tx_abort(tx);
zfs_range_unlock(rl);
blk_end_request(req, -error, size);
- return;
+ goto out;
}
error = dmu_write_req(zv->zv_objset, ZVOL_OBJ, req, tx);
zil_commit(zv->zv_zilog, ZVOL_OBJ);
blk_end_request(req, -error, size);
+out:
+ current->flags &= ~PF_NOFS;
}
#ifdef HAVE_BLK_QUEUE_DISCARD
struct request *req = (struct request *)arg;
struct request_queue *q = req->q;
zvol_state_t *zv = q->queuedata;
- uint64_t offset = blk_rq_pos(req) << 9;
- uint64_t size = blk_rq_bytes(req);
+ uint64_t start = blk_rq_pos(req) << 9;
+ uint64_t end = start + blk_rq_bytes(req);
int error;
rl_t *rl;
- if (offset + size > zv->zv_volsize) {
- blk_end_request(req, -EIO, size);
- return;
+ /*
+ * Annotate this call path with a flag that indicates that it is
+ * unsafe to use KM_SLEEP during memory allocations due to the
+ * potential for a deadlock. KM_PUSHPAGE should be used instead.
+ */
+ ASSERT(!(current->flags & PF_NOFS));
+ current->flags |= PF_NOFS;
+
+ if (end > zv->zv_volsize) {
+ blk_end_request(req, -EIO, blk_rq_bytes(req));
+ goto out;
}
- if (size == 0) {
- blk_end_request(req, 0, size);
- return;
+ /*
+ * Align the request to volume block boundaries. If we don't,
+ * then this will force dnode_free_range() to zero out the
+ * unaligned parts, which is slow (read-modify-write) and
+ * useless since we are not freeing any space by doing so.
+ */
+ start = P2ROUNDUP(start, zv->zv_volblocksize);
+ end = P2ALIGN(end, zv->zv_volblocksize);
+
+ if (start >= end) {
+ blk_end_request(req, 0, blk_rq_bytes(req));
+ goto out;
}
- rl = zfs_range_lock(&zv->zv_znode, offset, size, RL_WRITER);
+ rl = zfs_range_lock(&zv->zv_znode, start, end - start, RL_WRITER);
- error = dmu_free_long_range(zv->zv_objset, ZVOL_OBJ, offset, size);
+ error = dmu_free_long_range(zv->zv_objset, ZVOL_OBJ, start, end - start);
/*
* TODO: maybe we should add the operation to the log.
zfs_range_unlock(rl);
- blk_end_request(req, -error, size);
+ blk_end_request(req, -error, blk_rq_bytes(req));
+out:
+ current->flags &= ~PF_NOFS;
}
#endif /* HAVE_BLK_QUEUE_DISCARD */
ASSERT(zio != NULL);
ASSERT(size != 0);
- zgd = (zgd_t *)kmem_zalloc(sizeof (zgd_t), KM_SLEEP);
+ zgd = (zgd_t *)kmem_zalloc(sizeof (zgd_t), KM_PUSHPAGE);
zgd->zgd_zilog = zv->zv_zilog;
zgd->zgd_rl = zfs_range_lock(&zv->zv_znode, offset, size, RL_READER);
{
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);
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);
}
{
zil_close(zv->zv_zilog);
zv->zv_zilog = NULL;
+
dmu_buf_rele(zv->zv_dbuf, zvol_tag);
zv->zv_dbuf = NULL;
+
+ /*
+ * Evict cached data
+ */
+ if (dsl_dataset_is_dirty(dmu_objset_ds(zv->zv_objset)) &&
+ !(zv->zv_flags & ZVOL_RDONLY))
+ txg_wait_synced(dmu_objset_pool(zv->zv_objset), 0);
+ (void) dmu_objset_evict_dbufs(zv->zv_objset);
+
dmu_objset_disown(zv->zv_objset, zvol_tag);
zv->zv_objset = NULL;
}
mutex_enter(&zvol_state_lock);
zv = zvol_find_by_dev(dev);
- kobj = zv ? get_disk(zv->zv_disk) : ERR_PTR(-ENOENT);
+ kobj = zv ? get_disk(zv->zv_disk) : NULL;
mutex_exit(&zvol_state_lock);
return kobj;
zvol_alloc(dev_t dev, const char *name)
{
zvol_state_t *zv;
+ 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)
goto out_kmem;
+#ifdef HAVE_ELEVATOR_CHANGE
+ error = elevator_change(zv->zv_queue, "noop");
+#endif /* HAVE_ELEVATOR_CHANGE */
+ if (error) {
+ printk("ZFS: Unable to set \"%s\" scheduler for zvol %s: %d\n",
+ "noop", name, error);
+ goto out_queue;
+ }
+
#ifdef HAVE_BLK_QUEUE_FLUSH
blk_queue_flush(zv->zv_queue, VDEV_REQ_FLUSH | VDEV_REQ_FUA);
#else
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;
blk_cleanup_queue(zv->zv_queue);
out_kmem:
kmem_free(zv, sizeof (zvol_state_t));
-out:
+
return NULL;
}
}
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;
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);
blk_queue_physical_block_size(zv->zv_queue, zv->zv_volblocksize);
blk_queue_io_opt(zv->zv_queue, zv->zv_volblocksize);
#ifdef HAVE_BLK_QUEUE_DISCARD
- blk_queue_max_discard_sectors(zv->zv_queue, UINT_MAX);
+ blk_queue_max_discard_sectors(zv->zv_queue,
+ (zvol_max_discard_blocks * zv->zv_volblocksize) >> 9);
+ blk_queue_discard_granularity(zv->zv_queue, zv->zv_volblocksize);
queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, zv->zv_queue);
#endif
#ifdef HAVE_BLK_QUEUE_NONROT
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:
dmu_objset_disown(os, zvol_tag);
- zv->zv_objset = NULL;
out_doi:
kmem_free(doi, sizeof(dmu_object_info_t));
out:
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);
if (strchr(dsname, '/') == NULL)
return 0;
- (void) __zvol_create_minor(dsname);
+ (void) __zvol_create_minor(dsname, B_FALSE);
return (0);
}
spa_t *spa = NULL;
int error = 0;
+ if (zvol_inhibit_dev)
+ return (0);
+
mutex_enter(&zvol_state_lock);
if (pool) {
error = dmu_objset_find_spa(NULL, pool, zvol_create_minors_cb,
zvol_state_t *zv, *zv_next;
char *str;
+ if (zvol_inhibit_dev)
+ return;
+
str = kmem_zalloc(MAXNAMELEN, KM_SLEEP);
if (pool) {
(void) strncpy(str, pool, strlen(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));
+ return (0);
- (void) zvol_create_minors(NULL);
+out2:
+ taskq_destroy(zvol_taskq);
+out1:
+ mutex_destroy(&zvol_state_lock);
+ list_destroy(&zvol_state_list);
- return (0);
+ return (error);
}
void
list_destroy(&zvol_state_list);
}
+module_param(zvol_inhibit_dev, uint, 0644);
+MODULE_PARM_DESC(zvol_inhibit_dev, "Do not create zvol device nodes");
+
module_param(zvol_major, uint, 0444);
MODULE_PARM_DESC(zvol_major, "Major number for zvol device");
module_param(zvol_threads, uint, 0444);
MODULE_PARM_DESC(zvol_threads, "Number of threads for zvol device");
+
+module_param(zvol_max_discard_blocks, ulong, 0444);
+MODULE_PARM_DESC(zvol_max_discard_blocks, "Max number of blocks to discard at once");
git://git.camperquake.de / zfs.git / blobdiff