Incremental: add --export handling.

If --export is given with --incremental, then
  MD_DEVNAME
is output which gives the name of the device (in /dev/md) that
is the array (or container) that the device would be added to.
Also
  MD_STARTED
is set to one of
  no
  unsafe
  yes
  nothing

to indicate if the array was started.  IF MD_STARTED=unsafe
then it may be appropriate to run
  mdadm -R /dev/md/$MD_DEVNAME
after a timeout to ensure newly degraded array are started.

If
  MD_FOREIGN=yes
it might be appropriate to suppress this as the array is
probably not critical.

Signed-off-by: NeilBrown <neilb@suse.de>

4 files changed, 94 insertions, 16 deletions

diff --git a/Assemble.c b/Assemble.c
index 11b77c28..44e905bb 100644
--- a/Assemble.c
+++ b/Assemble.c
@@ -1419,7 +1419,7 @@ try_again:
 		/* This is a member of a container.  Try starting the array. */
 		int err;
 		err = assemble_container_content(st, mdfd, content, c,
-						 chosen_name);
+						 chosen_name, NULL);
 		close(mdfd);
 		return err;
 	}
@@ -1771,7 +1771,7 @@ try_again:
 #ifndef MDASSEMBLE
 int assemble_container_content(struct supertype *st, int mdfd,
 			       struct mdinfo *content, struct context *c,
-			       char *chosen_name)
+			       char *chosen_name, int *result)
 {
 	struct mdinfo *dev, *sra;
 	int working = 0, preexist = 0;
@@ -1838,7 +1838,9 @@ int assemble_container_content(struct supertype *st, int mdfd,
 
 	if (enough(content->array.level, content->array.raid_disks,
 		   content->array.layout, content->array.state & 1, avail) == 0) {
-		if (c->verbose >= 0) {
+		if (c->export && result)
+			*result |= INCR_NO;
+		else if (c->verbose >= 0) {
 			pr_err("%s assembled with %d device%s",
 			       chosen_name, preexist + working,
 			       preexist + working == 1 ? "":"s");
@@ -1854,7 +1856,9 @@ int assemble_container_content(struct supertype *st, int mdfd,
 	if (c->runstop <= 0 &&
 	    (working + preexist + expansion) <
 	    content->array.working_disks) {
-		if (c->verbose >= 0) {
+		if (c->export && result)
+			*result |= INCR_UNSAFE;
+		else if (c->verbose >= 0) {
 			pr_err("%s assembled with %d device%s",
 			       chosen_name, preexist + working,
 			       preexist + working == 1 ? "":"s");
@@ -1918,7 +1922,12 @@ int assemble_container_content(struct supertype *st, int mdfd,
 	    !start_reshape)
 		block_subarray(content);
 
-	if (c->verbose >= 0) {
+	if (c->export && result) {
+		if (err)
+			*result |= INCR_NO;
+		else
+			*result |= INCR_YES;
+	} else if (c->verbose >= 0) {
 		if (err)
 			pr_err("array %s now has %d device%s",
 			       chosen_name, working + preexist,
diff --git a/Incremental.c b/Incremental.c
index d082e61d..0703deae 100644
--- a/Incremental.c
+++ b/Incremental.c
@@ -91,6 +91,7 @@ int Incremental(char *devname, struct context *c,
 	struct mdinfo *sra = NULL, *d;
 	struct mddev_ident *match;
 	char chosen_name[1024];
+	char *md_devname;
 	int rv = 1;
 	struct map_ent *mp, *map = NULL;
 	int dfd = -1, mdfd = -1;
@@ -138,6 +139,8 @@ int Incremental(char *devname, struct context *c,
 			if (map_lock(&map))
 				pr_err("failed to get "
 				       "exclusive lock on mapfile\n");
+			if (c->export)
+				printf("MD_DEVNAME=%s\n", devname);
 			rv = Incremental_container(st, devname, c, NULL);
 			map_unlock(&map);
 			return rv;
@@ -459,6 +462,15 @@ int Incremental(char *devname, struct context *c,
 			info.array.working_disks ++;
 
 	}
+	if (strncmp(chosen_name, "/dev/md/", 8) == 0)
+		md_devname = chosen_name+8;
+	else
+		md_devname = chosen_name;
+	if (c->export) {
+		printf("MD_DEVICE=%s\n", fd2devnm(mdfd));
+		printf("MD_DEVNAME=%s\n", md_devname);
+		printf("MD_FOREIGN=%s\n", trustworthy == FOREIGN ? "yes" : "no");
+	}
 
 	/* 7/ Is there enough devices to possibly start the array? */
 	/* 7a/ if not, finish with success. */
@@ -466,7 +478,7 @@ int Incremental(char *devname, struct context *c,
 		char devnm[32];
 		/* Try to assemble within the container */
 		sysfs_uevent(sra, "change");
-		if (c->verbose >= 0)
+		if (!c->export && c->verbose >= 0)
 			pr_err("container %s now has %d device%s\n",
 			       chosen_name, info.array.working_disks,
 			       info.array.working_disks == 1?"":"s");
@@ -498,7 +510,9 @@ int Incremental(char *devname, struct context *c,
 	if (enough(info.array.level, info.array.raid_disks,
 		   info.array.layout, info.array.state & 1,
 		   avail) == 0) {
-		if (c->verbose >= 0)
+		if (c->export) {
+			printf("MD_STARTED=no\n");
+		} else if (c->verbose >= 0)
 			pr_err("%s attached to %s, not enough to start (%d).\n",
 			       devname, chosen_name, active_disks);
 		rv = 0;
@@ -512,7 +526,9 @@ int Incremental(char *devname, struct context *c,
 	/*   + start the array (auto-readonly). */
 
 	if (ioctl(mdfd, GET_ARRAY_INFO, &ainf) == 0) {
-		if (c->verbose >= 0)
+		if (c->export) {
+			printf("MD_STARTED=already\n");
+		} else if (c->verbose >= 0)
 			pr_err("%s attached to %s which is already active.\n",
 			       devname, chosen_name);
 		rv = 0;
@@ -559,7 +575,9 @@ int Incremental(char *devname, struct context *c,
 			rv = sysfs_set_str(sra, NULL,
 					   "array_state", "read-auto");
 		if (rv == 0) {
-			if (c->verbose >= 0)
+		if (c->export) {
+			printf("MD_STARTED=yes\n");
+		} else if (c->verbose >= 0)
 				pr_err("%s attached to %s, which has been started.\n",
 				       devname, chosen_name);
 			rv = 0;
@@ -582,7 +600,9 @@ int Incremental(char *devname, struct context *c,
 			rv = 1;
 		}
 	} else {
-		if (c->verbose >= 0)
+		if (c->export) {
+			printf("MD_STARTED=unsafe\n");
+		} else if (c->verbose >= 0)
 			pr_err("%s attached to %s, not enough to start safely.\n",
 			       devname, chosen_name);
 		rv = 0;
@@ -1436,6 +1456,7 @@ static int Incremental_container(struct supertype *st, char *devname,
 	int sfd;
 	int ra_blocked = 0;
 	int ra_all = 0;
+	int result = 0;
 
 	st->ss->getinfo_super(st, &info, NULL);
 
@@ -1443,7 +1464,9 @@ static int Incremental_container(struct supertype *st, char *devname,
 	    info.container_enough > 0)
 		/* pass */;
 	else {
-		if (c->verbose)
+		if (c->export) {
+			printf("MD_STARTED=no\n");
+		} else if (c->verbose)
 			pr_err("not enough devices to start the container\n");
 		return 0;
 	}
@@ -1464,8 +1487,12 @@ static int Incremental_container(struct supertype *st, char *devname,
 
 	list = st->ss->container_content(st, NULL);
 	/* when nothing to activate - quit */
-	if (list == NULL)
+	if (list == NULL) {
+		if (c->export) {
+			printf("MD_STARTED=nothing\n");
+		}
 		return 0;
+	}
 	for (ra = list ; ra ; ra = ra->next) {
 		int mdfd;
 		char chosen_name[1024];
@@ -1555,9 +1582,30 @@ static int Incremental_container(struct supertype *st, char *devname,
 		}
 
 		assemble_container_content(st, mdfd, ra, c,
-					   chosen_name);
+					   chosen_name, &result);
 		close(mdfd);
 	}
+	if (c->export && result) {
+		char sep = '=';
+		printf("MD_STARTED");
+		if (result & INCR_NO) {
+			printf("%cno", sep);
+			sep = ',';
+		}
+		if (result & INCR_UNSAFE) {
+			printf("%cunsafe", sep);
+			sep = ',';
+		}
+		if (result & INCR_ALREADY) {
+			printf("%calready", sep);
+			sep = ',';
+		}
+		if (result & INCR_YES) {
+			printf("%cyes", sep);
+			sep = ',';
+		}
+		printf("\n");
+	}
 
 	/* don't move spares to container with volume being activated
 	   when all volumes are blocked */
diff --git a/mdadm.8.in b/mdadm.8.in
index 61cb4f71..f49822ec 100644
--- a/mdadm.8.in
+++ b/mdadm.8.in
@@ -1440,13 +1440,30 @@ absolute filepath or a link, e.g.
 .TP
 .BR \-Y ", " \-\-export
 When used with
-.B \-\-detail , \-\-detail-platform
-or
+.BR \-\-detail ,
+.BR \-\-detail-platform ,
 .BR \-\-examine ,
+or
+.B \-\-incremental
 output will be formatted as
 .B key=value
 pairs for easy import into the environment.
 
+With
+.B \-\-incremental
+The value
+.B MD_STARTED
+indicates whether an array was started
+.RB ( yes )
+or not, which may include a reason
+.RB ( unsafe ", " nothing ", " no ).
+Also the value
+.B MD_FOREIGN
+indicates if the array is expected on this host
+.RB ( no ),
+or seems to be from elsewhere
+.RB ( yes ).
+
 .TP
 .BR \-E ", " \-\-examine
 Print contents of the metadata stored on the named device(s).
diff --git a/mdadm.h b/mdadm.h
index 7cfdd8fd..c38fdfb9 100644
--- a/mdadm.h
+++ b/mdadm.h
@@ -1331,7 +1331,11 @@ extern void append_metadata_update(struct supertype *st, void *buf, int len);
 extern int assemble_container_content(struct supertype *st, int mdfd,
 				      struct mdinfo *content,
 				      struct context *c,
-				      char *chosen_name);
+				      char *chosen_name, int *result);
+#define	INCR_NO		1
+#define	INCR_UNSAFE	2
+#define	INCR_ALREADY	4
+#define	INCR_YES	8
 extern struct mdinfo *container_choose_spares(struct supertype *st,
 					      unsigned long long min_size,
 					      struct domainlist *domlist,