ZIL claiming should not start user accounting

Currently, ZIL claiming dirties objsets which causes
dsl_pool_sync() to attempt to perform user accounting on
them. This causes problems for encrypted datasets that were
raw received before the system went offline since they
cannot perform user accounting until they have their keys
loaded. This triggers an ASSERT in zio_encrypt(). Since
encryption was added, the code now depends on the fact that
data should only be written when objsets are owned. This
patch adds a check in dmu_objset_do_userquota_updates()
to ensure that useraccounting is only done when the objsets
are actually owned for write. As part of this work, the
zfsvfs and zvol code was updated so that it no longer lies
about owning objsets readonly.

Reviewed-by: Brian Behlendorf <[email protected]>
Signed-off-by: Tom Caputi <[email protected]>
Closes #6916 
Closes #7163 

1 files changed, 6 insertions, 10 deletions

diff --git a/module/zfs/zvol.c b/module/zfs/zvol.c
index 572018d75..b0622c2ba 100644
--- a/module/zfs/zvol.c
+++ b/module/zfs/zvol.c
@@ -1289,10 +1289,11 @@ zvol_resume(zvol_state_t *zv)
 }
 
 static int
-zvol_first_open(zvol_state_t *zv)
+zvol_first_open(zvol_state_t *zv, boolean_t readonly)
 {
 	objset_t *os;
 	int error, locked = 0;
+	boolean_t ro;
 
 	ASSERT(RW_READ_HELD(&zv->zv_suspend_lock));
 	ASSERT(MUTEX_HELD(&zv->zv_state_lock));
@@ -1321,8 +1322,8 @@ zvol_first_open(zvol_state_t *zv)
 			return (-SET_ERROR(ERESTARTSYS));
 	}
 
-	/* lie and say we're read-only */
-	error = dmu_objset_own(zv->zv_name, DMU_OST_ZVOL, 1, 1, zv, &os);
+	ro = (readonly || (strchr(zv->zv_name, '@') != NULL));
+	error = dmu_objset_own(zv->zv_name, DMU_OST_ZVOL, ro, B_TRUE, zv, &os);
 	if (error)
 		goto out_mutex;
 
@@ -1401,17 +1402,12 @@ zvol_open(struct block_device *bdev, fmode_t flag)
 	ASSERT(zv->zv_open_count != 0 || RW_READ_HELD(&zv->zv_suspend_lock));
 
 	if (zv->zv_open_count == 0) {
-		error = zvol_first_open(zv);
+		error = zvol_first_open(zv, !(flag & FMODE_WRITE));
 		if (error)
 			goto out_mutex;
 	}
 
-	/*
-	 * Check for a bad on-disk format version now since we
-	 * lied about owning the dataset readonly before.
-	 */
-	if ((flag & FMODE_WRITE) && ((zv->zv_flags & ZVOL_RDONLY) ||
-	    dmu_objset_incompatible_encryption_version(zv->zv_objset))) {
+	if ((flag & FMODE_WRITE) && (zv->zv_flags & ZVOL_RDONLY)) {
 		error = -EROFS;
 		goto out_open_count;
 	}