kmem_zalloc(..., KM_SLEEP) will never fail

[zfs.git] / module / zfs / zvol.c

diff --git a/module/zfs/zvol.c b/module/zfs/zvol.c
index c6cfac2..43a7bb6 100644 (file)
--- a/module/zfs/zvol.c
+++ b/module/zfs/zvol.c
@@ -453,20 +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 */
 };
 
 /*
@@ -941,7 +941,8 @@ 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)) {
+       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 {
@@ -1213,8 +1214,6 @@ 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;
 
        zv->zv_queue = blk_init_queue(zvol_request, &zv->zv_lock);
        if (zv->zv_queue == NULL)
@@ -1266,7 +1265,7 @@ out_queue:
        blk_cleanup_queue(zv->zv_queue);
 out_kmem:
        kmem_free(zv, sizeof (zvol_state_t));
-out:
+
        return NULL;
 }
 
@@ -1287,7 +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;
@@ -1304,6 +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);
@@ -1352,10 +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:
@@ -1383,7 +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);
@@ -1431,7 +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);
 }
 
@@ -1499,6 +1527,35 @@ 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)
 {