Add 'zfs wait' command

Add a mechanism to wait for delete queue to drain.

When doing redacted send/recv, many workflows involve deleting files 
that contain sensitive data. Because of the way zfs handles file 
deletions, snapshots taken quickly after a rm operation can sometimes 
still contain the file in question, especially if the file is very 
large. This can result in issues for redacted send/recv users who 
expect the deleted files to be redacted in the send streams, and not 
appear in their clones.

This change duplicates much of the zpool wait related logic into a 
zfs wait command, which can be used to wait until the internal
deleteq has been drained.  Additional wait activities may be added 
in the future. 

Reviewed-by: Matthew Ahrens <[email protected]>
Reviewed-by: Brian Behlendorf <[email protected]>
Reviewed-by: John Gallagher <[email protected]>
Signed-off-by: Paul Dagnelie <[email protected]>
Closes #9707 

1 files changed, 90 insertions, 1 deletions

diff --git a/cmd/zfs/zfs_main.c b/cmd/zfs/zfs_main.c
index 5e5bbc972..ae71cdc88 100644
--- a/cmd/zfs/zfs_main.c
+++ b/cmd/zfs/zfs_main.c
@@ -122,6 +122,7 @@ static int zfs_do_change_key(int argc, char **argv);
 static int zfs_do_project(int argc, char **argv);
 static int zfs_do_version(int argc, char **argv);
 static int zfs_do_redact(int argc, char **argv);
+static int zfs_do_wait(int argc, char **argv);
 
 #ifdef __FreeBSD__
 static int zfs_do_jail(int argc, char **argv);
@@ -183,7 +184,8 @@ typedef enum {
 	HELP_VERSION,
 	HELP_REDACT,
 	HELP_JAIL,
-	HELP_UNJAIL
+	HELP_UNJAIL,
+	HELP_WAIT,
 } zfs_help_t;
 
 typedef struct zfs_command {
@@ -248,6 +250,7 @@ static zfs_command_t command_table[] = {
 	{ "unload-key",	zfs_do_unload_key,	HELP_UNLOAD_KEY		},
 	{ "change-key",	zfs_do_change_key,	HELP_CHANGE_KEY		},
 	{ "redact",	zfs_do_redact,		HELP_REDACT		},
+	{ "wait",	zfs_do_wait,		HELP_WAIT		},
 
 #ifdef __FreeBSD__
 	{ "jail",	zfs_do_jail,		HELP_JAIL		},
@@ -410,6 +413,8 @@ get_usage(zfs_help_t idx)
 		return (gettext("\tjail <jailid|jailname> <filesystem>\n"));
 	case HELP_UNJAIL:
 		return (gettext("\tunjail <jailid|jailname> <filesystem>\n"));
+	case HELP_WAIT:
+		return (gettext("\twait [-t <activity>] <filesystem>\n"));
 	}
 
 	abort();
@@ -8317,6 +8322,90 @@ zfs_do_project(int argc, char **argv)
 	return (ret);
 }
 
+static int
+zfs_do_wait(int argc, char **argv)
+{
+	boolean_t enabled[ZFS_WAIT_NUM_ACTIVITIES];
+	int error, i;
+	char c;
+
+	/* By default, wait for all types of activity. */
+	for (i = 0; i < ZFS_WAIT_NUM_ACTIVITIES; i++)
+		enabled[i] = B_TRUE;
+
+	while ((c = getopt(argc, argv, "t:")) != -1) {
+		switch (c) {
+		case 't':
+		{
+			static char *col_subopts[] = { "deleteq", NULL };
+			char *value;
+
+			/* Reset activities array */
+			bzero(&enabled, sizeof (enabled));
+			while (*optarg != '\0') {
+				int activity = getsubopt(&optarg, col_subopts,
+				    &value);
+
+				if (activity < 0) {
+					(void) fprintf(stderr,
+					    gettext("invalid activity '%s'\n"),
+					    value);
+					usage(B_FALSE);
+				}
+
+				enabled[activity] = B_TRUE;
+			}
+			break;
+		}
+		case '?':
+			(void) fprintf(stderr, gettext("invalid option '%c'\n"),
+			    optopt);
+			usage(B_FALSE);
+		}
+	}
+
+	argv += optind;
+	argc -= optind;
+	if (argc < 1) {
+		(void) fprintf(stderr, gettext("missing 'filesystem' "
+		    "argument\n"));
+		usage(B_FALSE);
+	}
+	if (argc > 1) {
+		(void) fprintf(stderr, gettext("too many arguments\n"));
+		usage(B_FALSE);
+	}
+
+	zfs_handle_t *zhp = zfs_open(g_zfs, argv[0], ZFS_TYPE_FILESYSTEM);
+	if (zhp == NULL)
+		return (1);
+
+	for (;;) {
+		boolean_t missing = B_FALSE;
+		boolean_t any_waited = B_FALSE;
+
+		for (int i = 0; i < ZFS_WAIT_NUM_ACTIVITIES; i++) {
+			boolean_t waited;
+
+			if (!enabled[i])
+				continue;
+
+			error = zfs_wait_status(zhp, i, &missing, &waited);
+			if (error != 0 || missing)
+				break;
+
+			any_waited = (any_waited || waited);
+		}
+
+		if (error != 0 || missing || !any_waited)
+			break;
+	}
+
+	zfs_close(zhp);
+
+	return (error);
+}
+
 /*
  * Display version message
  */