Apply fix Solaris bug 6462803 zfs snapshot -r failed because

filesystem was busy.

Submitted by:	mm
Approved by:	pjd
MFC after:	2 weeks

3 files changed, 49 insertions, 28 deletions

diff --git a/cddl/contrib/opensolaris/cmd/zdb/zdb_il.c b/cddl/contrib/opensolaris/cmd/zdb/zdb_il.c
index 02d35a0..cc08ef5 100644
--- a/cddl/contrib/opensolaris/cmd/zdb/zdb_il.c
+++ b/cddl/contrib/opensolaris/cmd/zdb/zdb_il.c
@@ -19,12 +19,10 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
-#pragma ident	"%Z%%M%	%I%	%E% SMI"
-
 /*
  * Print intent log header and statistics.
  */
@@ -345,8 +343,10 @@ dump_intent_log(zilog_t *zilog)
 	if (zh->zh_log.blk_birth == 0 || verbose < 2)
 		return;
 
-	(void) printf("\n    ZIL header: claim_txg %llu, seq %llu\n",
-	    (u_longlong_t)zh->zh_claim_txg, (u_longlong_t)zh->zh_replay_seq);
+	(void) printf("\n    ZIL header: claim_txg %llu, claim_seq %llu",
+	    (u_longlong_t)zh->zh_claim_txg, (u_longlong_t)zh->zh_claim_seq);
+	(void) printf(" replay_seq %llu, flags 0x%llx\n",
+	    (u_longlong_t)zh->zh_replay_seq, (u_longlong_t)zh->zh_flags);
 
 	if (verbose >= 4)
 		print_log_bp(&zh->zh_log, "\n\tfirst block: ");
diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/zil.h b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/zil.h
index 4d02d14..5212aaf 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/zil.h
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/zil.h
@@ -19,7 +19,7 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
@@ -56,10 +56,16 @@ typedef struct zil_header {
 	uint64_t zh_replay_seq;	/* highest replayed sequence number */
 	blkptr_t zh_log;	/* log chain */
 	uint64_t zh_claim_seq;	/* highest claimed sequence number */
-	uint64_t zh_pad[5];
+	uint64_t zh_flags;	/* header flags */
+	uint64_t zh_pad[4];
 } zil_header_t;
 
 /*
+ * zh_flags bit settings
+ */
+#define	ZIL_REPLAY_NEEDED 0x1	/* replay needed - internal only */
+
+/*
  * Log block trailer - structure at the end of the header and each log block
  *
  * The zit_bt contains a zbt_cksum which for the intent log is
diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zil.c b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zil.c
index a7c2b37..4455fb8 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zil.c
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zil.c
@@ -502,6 +502,25 @@ zil_rollback_destroy(zilog_t *zilog, dmu_tx_t *tx)
 	    tx, zh->zh_claim_txg);
 }
 
+/*
+ * return true if the initial log block is not valid
+ */
+static boolean_t
+zil_empty(zilog_t *zilog)
+{
+	const zil_header_t *zh = zilog->zl_header;
+	arc_buf_t *abuf = NULL;
+
+	if (BP_IS_HOLE(&zh->zh_log))
+		return (B_TRUE);
+
+	if (zil_read_log_block(zilog, &zh->zh_log, &abuf) != 0)
+		return (B_TRUE);
+
+	VERIFY(arc_buf_remove_ref(abuf, &abuf) == 1);
+	return (B_FALSE);
+}
+
 int
 zil_claim(char *osname, void *txarg)
 {
@@ -522,6 +541,21 @@ zil_claim(char *osname, void *txarg)
 	zh = zil_header_in_syncing_context(zilog);
 
 	/*
+	 * Record here whether the zil has any records to replay.
+	 * If the header block pointer is null or the block points
+	 * to the stubby then we know there are no valid log records.
+	 * We use the header to store this state as the the zilog gets
+	 * freed later in dmu_objset_close().
+	 * The flags (and the rest of the header fields) are cleared in
+	 * zil_sync() as a result of a zil_destroy(), after replaying the log.
+	 *
+	 * Note, the intent log can be empty but still need the
+	 * stubby to be claimed.
+	 */
+	if (!zil_empty(zilog))
+		zh->zh_flags |= ZIL_REPLAY_NEEDED;
+
+	/*
 	 * Claim all log blocks if we haven't already done so, and remember
 	 * the highest claimed sequence number.  This ensures that if we can
 	 * read only part of the log now (e.g. due to a missing device),
@@ -1345,25 +1379,6 @@ zil_free(zilog_t *zilog)
 }
 
 /*
- * return true if the initial log block is not valid
- */
-static boolean_t
-zil_empty(zilog_t *zilog)
-{
-	const zil_header_t *zh = zilog->zl_header;
-	arc_buf_t *abuf = NULL;
-
-	if (BP_IS_HOLE(&zh->zh_log))
-		return (B_TRUE);
-
-	if (zil_read_log_block(zilog, &zh->zh_log, &abuf) != 0)
-		return (B_TRUE);
-
-	VERIFY(arc_buf_remove_ref(abuf, &abuf) == 1);
-	return (B_FALSE);
-}
-
-/*
  * Open an intent log.
  */
 zilog_t *
@@ -1418,7 +1433,7 @@ zil_suspend(zilog_t *zilog)
 	const zil_header_t *zh = zilog->zl_header;
 
 	mutex_enter(&zilog->zl_lock);
-	if (zh->zh_claim_txg != 0) {		/* unplayed log */
+	if (zh->zh_flags & ZIL_REPLAY_NEEDED) {		/* unplayed log */
 		mutex_exit(&zilog->zl_lock);
 		return (EBUSY);
 	}
@@ -1645,7 +1660,7 @@ zil_replay(objset_t *os, void *arg, uint64_t *txgp,
 	const zil_header_t *zh = zilog->zl_header;
 	zil_replay_arg_t zr;
 
-	if (zil_empty(zilog)) {
+	if ((zh->zh_flags & ZIL_REPLAY_NEEDED) == 0) {
 		zil_destroy(zilog, B_TRUE);
 		return;
 	}