Illumos 4390 - I/O errors can corrupt space map when deleting fs/vol

4390 i/o errors when deleting filesystem/zvol can lead to space map corruption
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Christopher Siden <christopher.siden@delphix.com>
Reviewed by: Adam Leventhal <ahl@delphix.com>
Reviewed by: Dan McDonald <danmcd@omniti.com>
Reviewed by: Saso Kiselkov <saso.kiselkov@nexenta.com>
Approved by: Dan McDonald <danmcd@omniti.com>

References:
  https://www.illumos.org/issues/4390
  https://github.com/illumos/illumos-gate/commit/7fd05ac

Porting notes:

Previous stack-reduction efforts in traverse_visitb() caused a fair
number of un-mergable pieces of code.  This patch should reduce its
stack footprint a bit more.

The new local bptree_entry_phys_t in bptree_add() is dynamically-allocated
using kmem_zalloc() for the purpose of stack reduction.

The new global zfs_free_leak_on_eio has been defined as an integer
rather than a boolean_t as was the case with the related zfs_recover
global.  Also, zfs_free_leak_on_eio's definition has been inserted into
zfs_debug.c for consistency with the existing definition of zfs_recover.
Illumos placed it in spa_misc.c.

Ported by: Tim Chase <tim@chase2k.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #2545

include/sys/bptree.h

@@ -19,7 +19,7 @@
  * CDDL HEADER END
  */
 /*
- * Copyright (c) 2012 by Delphix. All rights reserved.
+ * Copyright (c) 2013 by Delphix. All rights reserved.
  */
 
 #ifndef	_SYS_BPTREE_H
@@ -50,6 +50,7 @@ typedef int bptree_itor_t(void *arg, const blkptr_t *bp, dmu_tx_t *tx);
 
 uint64_t bptree_alloc(objset_t *os, dmu_tx_t *tx);
 int bptree_free(objset_t *os, uint64_t obj, dmu_tx_t *tx);
+boolean_t bptree_is_empty(objset_t *os, uint64_t obj);
 
 void bptree_add(objset_t *os, uint64_t obj, blkptr_t *bp, uint64_t birth_txg,
     uint64_t bytes, uint64_t comp, uint64_t uncomp, dmu_tx_t *tx);

include/sys/dmu.h

@@ -250,7 +250,6 @@ void zfs_znode_byteswap(void *buf, size_t size);
 
 #define	DMU_USERUSED_OBJECT	(-1ULL)
 #define	DMU_GROUPUSED_OBJECT	(-2ULL)
-#define	DMU_DEADLIST_OBJECT	(-3ULL)
 
 /*
  * artificial blkids for bonus buffer and spill blocks

include/sys/dsl_dir.h

@@ -144,6 +144,7 @@ void dsl_dir_set_reservation_sync_impl(dsl_dir_t *dd, uint64_t value,
 #define	ORIGIN_DIR_NAME "$ORIGIN"
 #define	XLATION_DIR_NAME "$XLATION"
 #define	FREE_DIR_NAME "$FREE"
+#define	LEAK_DIR_NAME "$LEAK"
 
 #ifdef ZFS_DEBUG
 #define	dprintf_dd(dd, fmt, ...) do { \

include/sys/dsl_pool.h

@@ -87,6 +87,7 @@ typedef struct dsl_pool {
 	struct dsl_dir *dp_root_dir;
 	struct dsl_dir *dp_mos_dir;
 	struct dsl_dir *dp_free_dir;
+	struct dsl_dir *dp_leak_dir;
 	struct dsl_dataset *dp_origin_snap;
 	uint64_t dp_root_dir_obj;
 	struct taskq *dp_iput_taskq;

include/sys/dsl_scan.h

@@ -116,6 +116,7 @@ typedef struct dsl_scan {
 	/* for freeing blocks */
 	boolean_t scn_is_bptree;
 	boolean_t scn_async_destroying;
+	boolean_t scn_async_stalled;
 
 	/* for debugging / information */
 	uint64_t scn_visited_this_txg;

include/sys/fs/zfs.h

@@ -193,6 +193,7 @@ typedef enum {
 	ZPOOL_PROP_COMMENT,
 	ZPOOL_PROP_EXPANDSZ,
 	ZPOOL_PROP_FREEING,
+	ZPOOL_PROP_LEAKED,
 	ZPOOL_NUM_PROPS
 } zpool_prop_t;
 

include/sys/zfs_debug.h

@@ -48,6 +48,7 @@ extern "C" {
 
 extern int zfs_flags;
 extern int zfs_recover;
+extern int zfs_free_leak_on_eio;
 
 #define	ZFS_DEBUG_DPRINTF	(1<<0)
 #define	ZFS_DEBUG_DBUF_VERIFY	(1<<1)