Illumos #3956, #3957, #3958, #3959, #3960, #3961, #3962

3956 ::vdev -r should work with pipelines
3957 ztest should update the cachefile before killing itself
3958 multiple scans can lead to partial resilvering
3959 ddt entries are not always resilvered
3960 dsl_scan can skip over dedup-ed blocks if physical birth != logical birth
3961 freed gang blocks are not resilvered and can cause pool to suspend
3962 ztest should print out zfs debug buffer before exiting
Reviewed by: Matthew Ahrens <[email protected]>
Reviewed by: Adam Leventhal <[email protected]>
Approved by: Richard Lowe <[email protected]>

References:
  https://www.illumos.org/issues/3956
  https://www.illumos.org/issues/3957
  https://www.illumos.org/issues/3958
  https://www.illumos.org/issues/3959
  https://www.illumos.org/issues/3960
  https://www.illumos.org/issues/3961
  https://www.illumos.org/issues/3962
  illumos/illumos-gate@b4952e17e8858d3225793b28788278de9fe6038d

Ported-by: Richard Yao <[email protected]>
Signed-off-by: Brian Behlendorf <[email protected]>

Porting notes:

1. zfs_dbgmsg_print() is only used in userland. Since we do not have
   mdb on Linux, it does not make sense to make it available in the
   kernel. This means that a build failure will occur if any future
   kernel patch depends on it. However, that is unlikely given that
   this functionality was added to support zdb.

2. zfs_dbgmsg_print() is only invoked for -VVV or greater log levels.
   This preserves the existing behavior of minimal noise when running
   with -V, and -VV.

3. In vdev_config_generate() the call to nvlist_alloc() was not
   changed to fnvlist_alloc() because we must pass KM_PUSHPAGE in
   the txg_sync context.

4 files changed, 37 insertions, 5 deletions

diff --git a/include/sys/dsl_scan.h b/include/sys/dsl_scan.h
index aae8c312a..bf8c5ac82 100644
--- a/include/sys/dsl_scan.h
+++ b/include/sys/dsl_scan.h
@@ -72,11 +72,42 @@ typedef enum dsl_scan_flags {
 	DSF_VISIT_DS_AGAIN = 1<<0,
 } dsl_scan_flags_t;
 
+/*
+ * Every pool will have one dsl_scan_t and this structure will contain
+ * in-memory information about the scan and a pointer to the on-disk
+ * representation (i.e. dsl_scan_phys_t). Most of the state of the scan
+ * is contained on-disk to allow the scan to resume in the event of a reboot
+ * or panic. This structure maintains information about the behavior of a
+ * running scan, some caching information, and how it should traverse the pool.
+ *
+ * The following members of this structure direct the behavior of the scan:
+ *
+ * scn_pausing -	a scan that cannot be completed in a single txg or
+ *			has exceeded its allotted time will need to pause.
+ *			When this flag is set the scanner will stop traversing
+ *			the pool and write out the current state to disk.
+ *
+ * scn_restart_txg -	directs the scanner to either restart or start a
+ *			a scan at the specified txg value.
+ *
+ * scn_done_txg -	when a scan completes its traversal it will set
+ *			the completion txg to the next txg. This is necessary
+ *			to ensure that any blocks that were freed during
+ *			the scan but have not yet been processed (i.e deferred
+ *			frees) are accounted for.
+ *
+ * This structure also maintains information about deferred frees which are
+ * a special kind of traversal. Deferred free can exist in either a bptree or
+ * a bpobj structure. The scn_is_bptree flag will indicate the type of
+ * deferred free that is in progress. If the deferred free is part of an
+ * asynchronous destroy then the scn_async_destroying flag will be set.
+ */
 typedef struct dsl_scan {
 	struct dsl_pool *scn_dp;
 
 	boolean_t scn_pausing;
 	uint64_t scn_restart_txg;
+	uint64_t scn_done_txg;
 	uint64_t scn_sync_start_time;
 	zio_t *scn_zio_root;
 
diff --git a/include/sys/fs/zfs.h b/include/sys/fs/zfs.h
index 6b2d0f508..e945b40a9 100644
--- a/include/sys/fs/zfs.h
+++ b/include/sys/fs/zfs.h
@@ -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 2011 Nexenta Systems, Inc.  All rights reserved.
  * Copyright (c) 2012, Joyent, Inc. All rights reserved.
  */
@@ -530,7 +530,7 @@ typedef struct zpool_rewind_policy {
 #define	ZPOOL_CONFIG_SPLIT_GUID		"split_guid"
 #define	ZPOOL_CONFIG_SPLIT_LIST		"guid_list"
 #define	ZPOOL_CONFIG_REMOVING		"removing"
-#define	ZPOOL_CONFIG_RESILVERING	"resilvering"
+#define	ZPOOL_CONFIG_RESILVER_TXG	"resilver_txg"
 #define	ZPOOL_CONFIG_COMMENT		"comment"
 #define	ZPOOL_CONFIG_SUSPENDED		"suspended"	/* not stored on disk */
 #define	ZPOOL_CONFIG_TIMESTAMP		"timestamp"	/* not stored on disk */
diff --git a/include/sys/vdev_impl.h b/include/sys/vdev_impl.h
index af6602083..45a2b5e48 100644
--- a/include/sys/vdev_impl.h
+++ b/include/sys/vdev_impl.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) 2013 by Delphix. All rights reserved.
  */
 
 #ifndef _SYS_VDEV_IMPL_H
@@ -182,7 +182,7 @@ struct vdev {
 	uint64_t	vdev_faulted;	/* persistent faulted state	*/
 	uint64_t	vdev_degraded;	/* persistent degraded state	*/
 	uint64_t	vdev_removed;	/* persistent removed state	*/
-	uint64_t	vdev_resilvering; /* persistent resilvering state */
+	uint64_t	vdev_resilver_txg; /* persistent resilvering state */
 	uint64_t	vdev_nparity;	/* number of parity devices for raidz */
 	char		*vdev_path;	/* vdev path (if any)		*/
 	char		*vdev_devid;	/* vdev devid (if any)		*/
diff --git a/include/sys/zfs_debug.h b/include/sys/zfs_debug.h
index 41e8c08a1..1013009fd 100644
--- a/include/sys/zfs_debug.h
+++ b/include/sys/zfs_debug.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) 2013 by Delphix. All rights reserved.
  */
 
 #ifndef _SYS_ZFS_DEBUG_H
@@ -95,6 +95,7 @@ extern void zfs_dbgmsg_fini(void);
 #define        zfs_dbgmsg(...) dprintf(__VA_ARGS__)
 #else
 extern void zfs_dbgmsg(const char *fmt, ...);
+extern void zfs_dbgmsg_print(const char *tag);
 #endif
 
 #ifndef _KERNEL