'mdadm --wait-clean' wait for array to be marked clean

For use in distro shutdown scripts with a RAID root file system.
Returns immediately if the array is 'readonly', or not an externally
managed array.  It is up to the distro's scripts to make sure no new
writes hit the device after this returns 'true'.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>

1 files changed, 88 insertions, 0 deletions

diff --git a/Monitor.c b/Monitor.c
index b02ab3ce..3197b42a 100644
--- a/Monitor.c
+++ b/Monitor.c
@@ -628,3 +628,91 @@ int Wait(char *dev)
 		mdstat_wait(5);
 	}
 }
+
+static char *clean_states[] = {
+	"clear", "inactive", "readonly", "read-auto", "clean", NULL };
+
+int WaitClean(char *dev)
+{
+	int fd;
+	struct mdinfo *mdi;
+	int rv = 1;
+	int devnum;
+
+	fd = open(dev, O_RDONLY); 
+	if (fd < 0) {
+		fprintf(stderr, Name ": Couldn't open %s: %s\n", dev, strerror(errno));
+		return 1;
+	}
+
+	devnum = fd2devnum(fd);
+	mdi = sysfs_read(fd, devnum, GET_VERSION|GET_LEVEL|GET_SAFEMODE);
+	if (!mdi) {
+		fprintf(stderr, Name ": Failed to read sysfs attributes for "
+			"%s\n", dev);
+		close(fd);
+		return 0;
+	}
+
+	switch(mdi->array.level) {
+	case LEVEL_LINEAR:
+	case LEVEL_MULTIPATH:
+	case 0:
+		/* safemode delay is irrelevant for these levels */
+		rv = 0;
+		
+	}
+
+	/* for internal metadata the kernel handles the final clean
+	 * transition, containers can never be dirty
+	 */
+	if (!is_subarray(mdi->text_version))
+		rv = 0;
+
+	/* safemode disabled ? */
+	if (mdi->safe_mode_delay == 0)
+		rv = 0;
+
+	if (rv) {
+		int state_fd = sysfs_open(fd2devnum(fd), NULL, "array_state");
+		unsigned long secs;
+		char buf[20];
+
+		secs = mdi->safe_mode_delay / 1000;
+		if (mdi->safe_mode_delay - secs * 1000)
+			secs++;
+		secs *= 2;
+
+		for (; secs; secs--) {
+			rv = read(state_fd, buf, sizeof(buf));
+			if (rv < 0)
+				break;
+			if (sysfs_match_word(buf, clean_states) <= 4)
+				break;
+			sleep(1);
+			lseek(state_fd, 0, SEEK_SET);
+		}
+		if (rv < 0)
+			rv = 1;
+		else if (secs) {
+			/* we need to ping to close the window between array
+			 * state transitioning to clean and the metadata being
+			 * marked clean
+			 */
+			if (ping_monitor(mdi->text_version) == 0)
+				rv = 0;
+		}
+		if (rv)
+			fprintf(stderr, Name ": Error waiting for %s to be clean\n",
+				dev);
+
+		close(state_fd);
+	}
+
+	sysfs_free(mdi);		
+	close(fd);
+
+	return rv;
+}
+
+