Illumos 4951 - ZFS administrative commands should use reserved space

4951 ZFS administrative commands should use reserved space, not with ENOSPC
Reviewed by: John Kennedy <[email protected]>
Reviewed by: George Wilson <[email protected]>
Reviewed by: Christopher Siden <[email protected]>
Reviewed by: Dan McDonald <[email protected]>
Approved by: Garrett D'Amore <[email protected]>

References:
  https://www.illumos.org/issues/4373
  https://github.com/illumos/illumos-gate/commit/7d46dc6

Ported by: Brian Behlendorf <[email protected]>

1 files changed, 36 insertions, 6 deletions

diff --git a/include/sys/dsl_synctask.h b/include/sys/dsl_synctask.h
index ef86fb64c..6139303c1 100644
--- a/include/sys/dsl_synctask.h
+++ b/include/sys/dsl_synctask.h
@@ -20,7 +20,7 @@
  */
 /*
  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
- * Copyright (c) 2012 by Delphix. All rights reserved.
+ * Copyright (c) 2012, 2014 by Delphix. All rights reserved.
  */
 
 #ifndef	_SYS_DSL_SYNCTASK_H
@@ -38,11 +38,41 @@ struct dsl_pool;
 typedef int (dsl_checkfunc_t)(void *, dmu_tx_t *);
 typedef void (dsl_syncfunc_t)(void *, dmu_tx_t *);
 
+typedef enum zfs_space_check {
+	/*
+	 * Normal space check: if there is less than 3.2% free space,
+	 * the operation will fail.  Operations which are logically
+	 * creating things should use this (e.g. "zfs create", "zfs snapshot").
+	 * User writes (via the ZPL / ZVOL) also fail at this point.
+	 */
+	ZFS_SPACE_CHECK_NORMAL,
+
+	/*
+	 * Space check allows use of half the slop space.  If there
+	 * is less than 1.6% free space, the operation will fail.  Most
+	 * operations should use this (e.g. "zfs set", "zfs rename"),
+	 * because we want them to succeed even after user writes are failing,
+	 * so that they can be used as part of the space recovery process.
+	 */
+	ZFS_SPACE_CHECK_RESERVED,
+
+	/*
+	 * No space check is performed.  Only operations which we expect to
+	 * result in a net reduction in space should use this
+	 * (e.g. "zfs destroy". Setting quotas & reservations also uses
+	 * this because it needs to circumvent the quota/reservation checks).
+	 *
+	 * See also the comments above spa_slop_shift.
+	 */
+	ZFS_SPACE_CHECK_NONE,
+} zfs_space_check_t;
+
 typedef struct dsl_sync_task {
 	txg_node_t dst_node;
 	struct dsl_pool *dst_pool;
 	uint64_t dst_txg;
 	int dst_space;
+	zfs_space_check_t dst_space_check;
 	dsl_checkfunc_t *dst_checkfunc;
 	dsl_syncfunc_t *dst_syncfunc;
 	void *dst_arg;
@@ -50,11 +80,11 @@ typedef struct dsl_sync_task {
 	boolean_t dst_nowaiter;
 } dsl_sync_task_t;
 
-void dsl_sync_task_sync(dsl_sync_task_t *dst, dmu_tx_t *tx);
-int dsl_sync_task(const char *pool, dsl_checkfunc_t *checkfunc,
-    dsl_syncfunc_t *syncfunc, void *arg, int blocks_modified);
-void dsl_sync_task_nowait(struct dsl_pool *dp, dsl_syncfunc_t *syncfunc,
-    void *arg, int blocks_modified, dmu_tx_t *tx);
+void dsl_sync_task_sync(dsl_sync_task_t *, dmu_tx_t *);
+int dsl_sync_task(const char *, dsl_checkfunc_t *,
+    dsl_syncfunc_t *, void *, int, zfs_space_check_t);
+void dsl_sync_task_nowait(struct dsl_pool *, dsl_syncfunc_t *,
+    void *, int, zfs_space_check_t, dmu_tx_t *);
 
 #ifdef	__cplusplus
 }