Allow WRITEMOSTLY to be cleared on --readd using --readwrite.

Previously it was possible to set the WRITEMOSTLY flag when
adding a device to an array, but not to clear the flag when re-adding.
This is now possible with --readwrite.

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

Build.c

@@ -183,7 +183,7 @@ int Build(char *mddev, int mdfd, int chunk, int level, int layout,
 			disk.number = i;
 			disk.raid_disk = i;
 			disk.state = (1<<MD_DISK_SYNC) | (1<<MD_DISK_ACTIVE);
-			if (dv->writemostly)
+			if (dv->writemostly == 1)
 				disk.state |= 1<<MD_DISK_WRITEMOSTLY;
 			disk.major = major(stb.st_rdev);
 			disk.minor = minor(stb.st_rdev);

ChangeLog

@@ -1,3 +1,7 @@
+Changed Prior to this release
+    -   --readwrite can be used with --re-add to clear the writemostly
+        flag.
+
 Changes Prior to 2.6.7 release
     -   Avoid NULL reference calling free_super and elsewhere.
     -   Remove stray semicolon (Causes compile error with gcc-2.95)

Create.c

@@ -534,7 +534,7 @@ int Create(struct supertype *st, char *mddev, int mdfd,
 						(1<<MD_DISK_SYNC);
 			else
 				info.disk.state = 0;
-			if (dv->writemostly)
+			if (dv->writemostly == 1)
 				info.disk.state |= (1<<MD_DISK_WRITEMOSTLY);
 
 			if (dnum == insert_point ||

Manage.c

@@ -413,8 +413,10 @@ int Manage_subdevs(char *devname, int fd,
 						disc.number = mdi.disk.number;
 						disc.raid_disk = mdi.disk.raid_disk;
 						disc.state = mdi.disk.state;
-						if (dv->writemostly)
+						if (dv->writemostly == 1)
 							disc.state |= 1 << MD_DISK_WRITEMOSTLY;
+						if (dv->writemostly == 2)
+							disc.state &= ~(1 << MD_DISK_WRITEMOSTLY);
 						if (ioctl(fd, ADD_NEW_DISK, &disc) == 0) {
 							if (verbose >= 0)
 								fprintf(stderr, Name ": re-added %s\n", dv->devname);
@@ -452,7 +454,7 @@ int Manage_subdevs(char *devname, int fd,
 			disc.number =j;
 			disc.state = 0;
 			if (array.not_persistent==0) {
-				if (dv->writemostly)
+				if (dv->writemostly == 1)
 					disc.state |= 1 << MD_DISK_WRITEMOSTLY;
 				tst->ss->add_to_super(tst, &disc);
 				if (tst->ss->write_init_super(tst, &disc,
@@ -487,7 +489,7 @@ int Manage_subdevs(char *devname, int fd,
 						break;
 					}
 			}
-			if (dv->writemostly)
+			if (dv->writemostly == 1)
 				disc.state |= (1 << MD_DISK_WRITEMOSTLY);
 			if (ioctl(fd,ADD_NEW_DISK, &disc)) {
 				fprintf(stderr, Name ": add new device failed for %s as %d: %s\n",

mdadm.8

@@ -905,6 +905,17 @@ the system to be marked as failed.  It can then be removed.
 same as
 .BR \-\-fail .
 
+.TP
+.BR \-\-write\-mostly
+Subsequent devices that are added or re-added will have the 'write-mostly'
+flag set.  This is only valid for RAID! and means that the 'md' driver
+will avoid reading from these devices if possible.
+.TP
+.BR \-\-readwrite
+Subsequent devices that are added or re-added will have the 'write-mostly'
+flag cleared.
+
+
 .P
 Each of these options require that the first device listed is the array
 to be acted upon, and the remainder are component devices to be added,

mdadm.c

@@ -360,6 +360,12 @@ int main(int argc, char *argv[])
 			writemostly = 1;
 			continue;
 
+		case O(MANAGE,'w'):
+			/* clear write-mostly for following devices */
+			writemostly = 2;
+			continue;
+
+
 		case O(GROW,'z'):
 		case O(CREATE,'z'): /* size */
 			if (size >= 0) {
@@ -745,21 +751,6 @@ int main(int argc, char *argv[])
 			runstop = -1;
 			continue;
 
-		case O(MANAGE,'o'):
-			if (readonly < 0) {
-				fprintf(stderr, Name ": Cannot have both readonly and readwrite\n");
-				exit(2);
-			}
-			readonly = 1;
-			continue;
-		case O(MANAGE,'w'):
-			if (readonly > 0) {
-				fprintf(stderr, Name ": Cannot have both readwrite and readonly.\n");
-				exit(2);
-			}
-			readonly = -1;
-			continue;
-
 		case O(MISC,'Q'):
 		case O(MISC,'D'):
 		case O(MISC,'E'):

mdadm.h

@@ -232,7 +232,7 @@ typedef struct mddev_dev_s {
 	char disposition;	/* 'a' for add, 'r' for remove, 'f' for fail.
 				 * Not set for names read from .config
 				 */
-	char writemostly;
+	char writemostly;	/* 1 for 'set writemostly', 2 for 'clear writemostly' */
 	char re_add;
 	char used;		/* set when used */
 	struct mddev_dev_s *next;