int
dsl_destroy_snapshot_check_impl(dsl_dataset_t *ds, boolean_t defer)
{
if (!ds->ds_is_snapshot)
return (SET_ERROR(EINVAL));
if (dsl_dataset_long_held(ds))
return (SET_ERROR(EBUSY));
/*
* Only allow deferred destroy on pools that support it.
* NOTE: deferred destroy is only supported on snapshots.
*/
if (defer) {
if (spa_version(ds->ds_dir->dd_pool->dp_spa) <
SPA_VERSION_USERREFS)
return (SET_ERROR(ENOTSUP));
return (0);
}
/*
* If this snapshot has an elevated user reference count,
* we can't destroy it yet.
*/
if (ds->ds_userrefs > 0)
return (SET_ERROR(EBUSY));
/*
* Can't delete a branch point.
*/
if (dsl_dataset_phys(ds)->ds_num_children > 1)
return (SET_ERROR(EEXIST));
return (0);
}
int
dmu_objset_from_ds(dsl_dataset_t *ds, objset_t **osp)
{
int err = 0;
/*
* We shouldn't be doing anything with dsl_dataset_t's unless the
* pool_config lock is held, or the dataset is long-held.
*/
ASSERT(dsl_pool_config_held(ds->ds_dir->dd_pool) ||
dsl_dataset_long_held(ds));
mutex_enter(&ds->ds_opening_lock);
if (ds->ds_objset == NULL) {
objset_t *os;
rrw_enter(&ds->ds_bp_rwlock, RW_READER, FTAG);
err = dmu_objset_open_impl(dsl_dataset_get_spa(ds),
ds, dsl_dataset_get_blkptr(ds), &os);
rrw_exit(&ds->ds_bp_rwlock, FTAG);
if (err == 0) {
mutex_enter(&ds->ds_lock);
ASSERT(ds->ds_objset == NULL);
ds->ds_objset = os;
mutex_exit(&ds->ds_lock);
}
}
*osp = ds->ds_objset;
mutex_exit(&ds->ds_opening_lock);
return (err);
}
/*
* When we are called, os MUST refer to an objset associated with a dataset
* that is owned by 'tag'; that is, is held and long held by 'tag' and ds_owner
* == tag. We will then release and reacquire ownership of the dataset while
* holding the pool config_rwlock to avoid intervening namespace or ownership
* changes may occur.
*
* This exists solely to accommodate zfs_ioc_userspace_upgrade()'s desire to
* release the hold on its dataset and acquire a new one on the dataset of the
* same name so that it can be partially torn down and reconstructed.
*/
void
dmu_objset_refresh_ownership(objset_t *os, void *tag)
{
dsl_pool_t *dp;
dsl_dataset_t *ds, *newds;
char name[MAXNAMELEN];
ds = os->os_dsl_dataset;
VERIFY3P(ds, !=, NULL);
VERIFY3P(ds->ds_owner, ==, tag);
VERIFY(dsl_dataset_long_held(ds));
dsl_dataset_name(ds, name);
dp = dmu_objset_pool(os);
dsl_pool_config_enter(dp, FTAG);
dmu_objset_disown(os, tag);
VERIFY0(dsl_dataset_own(dp, name, tag, &newds));
VERIFY3P(newds, ==, os->os_dsl_dataset);
dsl_pool_config_exit(dp, FTAG);
}
static int
dsl_dataset_user_release_check_one(dsl_dataset_t *ds,
nvlist_t *holds, boolean_t *todelete)
{
uint64_t zapobj;
nvpair_t *pair;
objset_t *mos = ds->ds_dir->dd_pool->dp_meta_objset;
int error;
int numholds = 0;
*todelete = B_FALSE;
if (!dsl_dataset_is_snapshot(ds))
return (EINVAL);
zapobj = ds->ds_phys->ds_userrefs_obj;
if (zapobj == 0)
return (ESRCH);
for (pair = nvlist_next_nvpair(holds, NULL); pair != NULL;
pair = nvlist_next_nvpair(holds, pair)) {
/* Make sure the hold exists */
uint64_t tmp;
error = zap_lookup(mos, zapobj, nvpair_name(pair), 8, 1, &tmp);
if (error == ENOENT)
error = ESRCH;
if (error != 0)
return (error);
numholds++;
}
if (DS_IS_DEFER_DESTROY(ds) && ds->ds_phys->ds_num_children == 1 &&
ds->ds_userrefs == numholds) {
/* we need to destroy the snapshot as well */
if (dsl_dataset_long_held(ds))
return (EBUSY);
*todelete = B_TRUE;
}
return (0);
}
static int
dsl_dataset_user_release_check_one(dsl_dataset_user_release_arg_t *ddura,
dsl_dataset_t *ds, nvlist_t *holds, const char *snapname)
{
uint64_t zapobj;
nvlist_t *holds_found;
objset_t *mos;
int numholds;
if (!dsl_dataset_is_snapshot(ds))
return (SET_ERROR(EINVAL));
if (nvlist_empty(holds))
return (0);
numholds = 0;
mos = ds->ds_dir->dd_pool->dp_meta_objset;
zapobj = ds->ds_phys->ds_userrefs_obj;
holds_found = fnvlist_alloc();
for (nvpair_t *pair = nvlist_next_nvpair(holds, NULL); pair != NULL;
pair = nvlist_next_nvpair(holds, pair)) {
uint64_t tmp;
int error;
const char *holdname = nvpair_name(pair);
if (zapobj != 0)
error = zap_lookup(mos, zapobj, holdname, 8, 1, &tmp);
else
error = SET_ERROR(ENOENT);
/*
* Non-existent holds are put on the errlist, but don't
* cause an overall failure.
*/
if (error == ENOENT) {
if (ddura->ddura_errlist != NULL) {
char *errtag = kmem_asprintf("%s#%s",
snapname, holdname);
fnvlist_add_int32(ddura->ddura_errlist, errtag,
ENOENT);
strfree(errtag);
}
continue;
}
if (error != 0) {
fnvlist_free(holds_found);
return (error);
}
fnvlist_add_boolean(holds_found, holdname);
numholds++;
}
if (DS_IS_DEFER_DESTROY(ds) && ds->ds_phys->ds_num_children == 1 &&
ds->ds_userrefs == numholds) {
/* we need to destroy the snapshot as well */
if (dsl_dataset_long_held(ds)) {
fnvlist_free(holds_found);
return (SET_ERROR(EBUSY));
}
fnvlist_add_boolean(ddura->ddura_todelete, snapname);
}
if (numholds != 0) {
fnvlist_add_nvlist(ddura->ddura_chkholds, snapname,
holds_found);
}
fnvlist_free(holds_found);
return (0);
}
/*
* Reopen zfs_sb_t and release VFS ops.
*/
int
zfs_resume_fs(zfs_sb_t *zsb, const char *osname)
{
int err, err2;
znode_t *zp;
uint64_t sa_obj = 0;
ASSERT(RRM_WRITE_HELD(&zsb->z_teardown_lock));
ASSERT(RW_WRITE_HELD(&zsb->z_teardown_inactive_lock));
/*
* We already own this, so just hold and rele it to update the
* objset_t, as the one we had before may have been evicted.
*/
VERIFY0(dmu_objset_hold(osname, zsb, &zsb->z_os));
VERIFY3P(zsb->z_os->os_dsl_dataset->ds_owner, ==, zsb);
VERIFY(dsl_dataset_long_held(zsb->z_os->os_dsl_dataset));
dmu_objset_rele(zsb->z_os, zsb);
/*
* Make sure version hasn't changed
*/
err = zfs_get_zplprop(zsb->z_os, ZFS_PROP_VERSION,
&zsb->z_version);
if (err)
goto bail;
err = zap_lookup(zsb->z_os, MASTER_NODE_OBJ,
ZFS_SA_ATTRS, 8, 1, &sa_obj);
if (err && zsb->z_version >= ZPL_VERSION_SA)
goto bail;
if ((err = sa_setup(zsb->z_os, sa_obj,
zfs_attr_table, ZPL_END, &zsb->z_attr_table)) != 0)
goto bail;
if (zsb->z_version >= ZPL_VERSION_SA)
sa_register_update_callback(zsb->z_os,
zfs_sa_upgrade);
VERIFY(zfs_sb_setup(zsb, B_FALSE) == 0);
zfs_set_fuid_feature(zsb);
zsb->z_rollback_time = jiffies;
/*
* Attempt to re-establish all the active inodes with their
* dbufs. If a zfs_rezget() fails, then we unhash the inode
* and mark it stale. This prevents a collision if a new
* inode/object is created which must use the same inode
* number. The stale inode will be be released when the
* VFS prunes the dentry holding the remaining references
* on the stale inode.
*/
mutex_enter(&zsb->z_znodes_lock);
for (zp = list_head(&zsb->z_all_znodes); zp;
zp = list_next(&zsb->z_all_znodes, zp)) {
err2 = zfs_rezget(zp);
if (err2) {
remove_inode_hash(ZTOI(zp));
zp->z_is_stale = B_TRUE;
}
}
mutex_exit(&zsb->z_znodes_lock);
bail:
/* release the VFS ops */
rw_exit(&zsb->z_teardown_inactive_lock);
rrm_exit(&zsb->z_teardown_lock, FTAG);
if (err) {
/*
* Since we couldn't setup the sa framework, try to force
* unmount this file system.
*/
if (zsb->z_os)
(void) zfs_umount(zsb->z_sb);
}
return (err);
}