Illumos #3829

3829 fix for 3740 changed behavior of zfs destroy/hold/release ioctl
Reviewed by: Matt Amdur <matt.amdur@delphix.com>
Reviewed by: Christopher Siden <christopher.siden@delphix.com>
Approved by: Richard Lowe <richlowe@richlowe.net>

References:
  https://www.illumos.org/issues/3829
  illumos/illumos-gate@bb6e70758d

Ported-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #1775

lib/libzfs/libzfs_dataset.c

@@ -21,7 +21,7 @@
 
 /*
  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
- * Copyright (c) 2012 by Delphix. All rights reserved.
+ * Copyright (c) 2013 by Delphix. All rights reserved.
  * Copyright (c) 2012 DEY Storage Systems, Inc.  All rights reserved.
  * Copyright (c) 2012 Pawel Jakub Dawidek <pawel@dawidek.net>.
  * Copyright 2012 Nexenta Systems, Inc. All rights reserved.
@@ -4412,6 +4412,7 @@ struct holdarg {
 	const char *snapname;
 	const char *tag;
 	boolean_t recursive;
+	int error;
 };
 
 static int
@@ -4539,15 +4540,20 @@ zfs_release_one(zfs_handle_t *zhp, void *arg)
 	struct holdarg *ha = arg;
 	char name[ZFS_MAXNAMELEN];
 	int rv = 0;
+	nvlist_t *existing_holds;
 
 	(void) snprintf(name, sizeof (name),
 	    "%s@%s", zhp->zfs_name, ha->snapname);
 
-	if (lzc_exists(name)) {
+	if (lzc_get_holds(name, &existing_holds) != 0) {
-		nvlist_t *holds = fnvlist_alloc();
+		ha->error = ENOENT;
-		fnvlist_add_boolean(holds, ha->tag);
+	} else if (!nvlist_exists(existing_holds, ha->tag)) {
-		fnvlist_add_nvlist(ha->nvl, name, holds);
+		ha->error = ESRCH;
-		fnvlist_free(holds);
+	} else {
+		nvlist_t *torelease = fnvlist_alloc();
+		fnvlist_add_boolean(torelease, ha->tag);
+		fnvlist_add_nvlist(ha->nvl, name, torelease);
+		fnvlist_free(torelease);
 	}
 
 	if (ha->recursive)
@@ -4571,16 +4577,21 @@ zfs_release(zfs_handle_t *zhp, const char *snapname, const char *tag,
 	ha.snapname = snapname;
 	ha.tag = tag;
 	ha.recursive = recursive;
+	ha.error = 0;
 	(void) zfs_release_one(zfs_handle_dup(zhp), &ha);
 
 	if (nvlist_empty(ha.nvl)) {
 		fnvlist_free(ha.nvl);
-		ret = ENOENT;
+		ret = ha.error;
 		(void) snprintf(errbuf, sizeof (errbuf),
 		    dgettext(TEXT_DOMAIN,
 		    "cannot release hold from snapshot '%s@%s'"),
 		    zhp->zfs_name, snapname);
-		(void) zfs_standard_error(hdl, ret, errbuf);
+		if (ret == ESRCH) {
+			(void) zfs_error(hdl, EZFS_REFTAG_RELE, errbuf);
+		} else {
+			(void) zfs_standard_error(hdl, ret, errbuf);
+		}
 		return (ret);
 	}
 

lib/libzfs_core/libzfs_core.c

@@ -255,11 +255,8 @@ lzc_snapshot(nvlist_t *snaps, nvlist_t *props, nvlist_t **errlist)
  * marked for deferred destruction, and will be destroyed when the last hold
  * or clone is removed/destroyed.
  *
- * The return value will be ENOENT if none of the snapshots existed.
- *
  * The return value will be 0 if all snapshots were destroyed (or marked for
- * later destruction if 'defer' is set) or didn't exist to begin with and
+ * later destruction if 'defer' is set) or didn't exist to begin with.
- * at least one snapshot was destroyed.
  *
  * Otherwise the return value will be the errno of a (unspecified) snapshot
  * that failed, no snapshots will be destroyed, and the errlist will have an
@@ -350,15 +347,10 @@ lzc_exists(const char *dataset)
  * or imported.
  *
  * Holds for snapshots which don't exist will be skipped and have an entry
- * added to errlist, but will not cause an overall failure, except in the
+ * added to errlist, but will not cause an overall failure.
- * case that all holds where skipped.
  *
- * The return value will be ENOENT if none of the snapshots for the requested
+ * The return value will be 0 if all holds, for snapshots that existed,
- * holds existed.
+ * were succesfully created.
- *
- * The return value will be 0 if the nvl holds was empty or all holds, for
- * snapshots that existed, were succesfully created and at least one hold
- * was created.
  *
  * Otherwise the return value will be the errno of a (unspecified) hold that
  * failed and no holds will be created.
@@ -402,13 +394,10 @@ lzc_hold(nvlist_t *holds, int cleanup_fd, nvlist_t **errlist)
  * The value is a nvlist whose keys are the holds to remove.
  *
  * Holds which failed to release because they didn't exist will have an entry
- * added to errlist, but will not cause an overall failure, except in the
+ * added to errlist, but will not cause an overall failure.
- * case that all releases where skipped.
- *
- * The return value will be ENOENT if none of the specified holds existed.
  *
  * The return value will be 0 if the nvl holds was empty or all holds that
- * existed, were successfully removed and at least one hold was removed.
+ * existed, were successfully removed.
  *
  * Otherwise the return value will be the errno of a (unspecified) hold that
  * failed to release and no holds will be released.

module/zfs/dsl_destroy.c

@@ -129,9 +129,6 @@ dsl_destroy_snapshot_check(void *arg, dmu_tx_t *tx)
 	if (pair != NULL)
 		return (fnvpair_value_int32(pair));
 
-	if (nvlist_empty(dsda->dsda_successful_snaps))
-		return (SET_ERROR(ENOENT));
-
 	return (0);
 }
 

module/zfs/dsl_userhold.c

@@ -127,10 +127,6 @@ dsl_dataset_user_hold_check(void *arg, dmu_tx_t *tx)
 		}
 	}
 
-	/* Return ENOENT if no holds would be created. */
-	if (nvlist_empty(dduha->dduha_chkholds))
-		return (SET_ERROR(ENOENT));
-
 	return (0);
 }
 
@@ -472,10 +468,6 @@ dsl_dataset_user_release_check(void *arg, dmu_tx_t *tx)
 		}
 	}
 
-	/* Return ENOENT if none of the holds existed. */
-	if (nvlist_empty(ddura->ddura_chkholds))
-		return (SET_ERROR(ENOENT));
-
 	return (0);
 }