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.
*/
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;
ASSERT(!(current->flags & PF_NOFS));
current->flags |= PF_NOFS;
- if (offset + size > zv->zv_volsize) {
- blk_end_request(req, -EIO, size);
+ 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);
+ /*
+ * 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;
}
{
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);
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;
+ 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);
}
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)
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
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:
git://git.camperquake.de / zfs.git / blobdiff