On Wed, 27 Jul 2011 14:34:37 -0400 Doug Ledford <dledford@xxxxxxxxxx> wrote:
> If you create a two drive raid1 array with one device writemostly, then
> fail the readwrite drive, when you add a new device, it will get the
> writemostly bit copied out of the remaining device's superblock into
> it's own. You can then remove the new drive and readd it as readwrite,
> which will work for the readd, but it leaves the stale WriteMostly1 bit
> in devflags resulting in the device going back to writemostly on the
> next assembly.
>
> The fix is to make sure that A) when we readd a device and we might have
> filled the st->sb info from a running device instead of the device being
> readded, then clear/set the WriteMostly1 bit in the super1 struct in
> addition to setting the disk state (ditto for super0, but slightly
> different mechanism) and B) when adding a clean device to an array (when
> we most certainly did copy the superblock info from an existing device),
> then clear any writemostly bits.
>
> Signed-off-by: Doug Ledford <dledford@xxxxxxxxxx>
Applied - thanks.
This function really needs to be refactored though - some of that indenting
is WAY too deep!!
Thanks,
NeilBrown
diff -up mdadm-3.2.2/Manage.c.writemostly mdadm-3.2.2/Manage.c
--- mdadm-3.2.2/Manage.c.writemostly 2011-06-13 22:50:01.000000000 -0400
+++ mdadm-3.2.2/Manage.c 2011-07-27 14:12:18.629889841 -0400
@@ -741,11 +741,24 @@ int Manage_subdevs(char *devname, int fd
remove_partitions(tfd);
close(tfd);
tfd = -1;
- if (update) {
+ if (update || dv->writemostly > 0) {
int rv = -1;
tfd = dev_open(dv->devname, O_RDWR);
+ if (tfd < 0) {
+ fprintf(stderr, Name ": failed to open %s for"
+ " superblock update during re-add\n", dv->devname);
+ return 1;
+ }
- if (tfd >= 0)
+ if (dv->writemostly == 1)
+ rv = st->ss->update_super(
+ st, NULL, "writemostly",
+ devname, verbose, 0, NULL);
+ if (dv->writemostly == 2)
+ rv = st->ss->update_super(
+ st, NULL, "readwrite",
+ devname, verbose, 0, NULL);
+ if (update)
rv = st->ss->update_super(
st, NULL, update,
devname, verbose, 0, NULL);
diff -up mdadm-3.2.2/mdadm.h.writemostly mdadm-3.2.2/mdadm.h
--- mdadm-3.2.2/mdadm.h.writemostly 2011-07-27 14:12:28.800779575 -0400
+++ mdadm-3.2.2/mdadm.h 2011-07-27 14:04:34.669932148 -0400
@@ -646,6 +646,8 @@ extern struct superswitch {
* linear-grow-new - add a new device to a linear array, but don't
* change the size: so superblock still matches
* linear-grow-update - now change the size of the array.
+ * writemostly - set the WriteMostly1 bit in the superblock devflags
+ * readwrite - clear the WriteMostly1 bit in the superblock devflags
*/
int (*update_super)(struct supertype *st, struct mdinfo *info,
char *update,
diff -up mdadm-3.2.2/super0.c.writemostly mdadm-3.2.2/super0.c
--- mdadm-3.2.2/super0.c.writemostly 2011-06-17 01:15:50.000000000 -0400
+++ mdadm-3.2.2/super0.c 2011-07-27 14:12:18.655889559 -0400
@@ -570,6 +570,10 @@ static int update_super0(struct supertyp
sb->state &= ~(1<<MD_SB_BITMAP_PRESENT);
} else if (strcmp(update, "_reshape_progress")==0)
sb->reshape_position = info->reshape_progress;
+ else if (strcmp(update, "writemostly")==0)
+ sb->state |= (1<<MD_DISK_WRITEMOSTLY);
+ else if (strcmp(update, "readwrite")==0)
+ sb->state &= ~(1<<MD_DISK_WRITEMOSTLY);
else
rv = -1;
@@ -688,6 +692,8 @@ static int add_to_super0(struct supertyp
dk->minor = dinfo->minor;
dk->raid_disk = dinfo->raid_disk;
dk->state = dinfo->state;
+ /* In case our source disk was writemostly, don't copy that bit */
+ dk->state &= ~(1<<MD_DISK_WRITEMOSTLY);
sb->this_disk = sb->disks[dinfo->number];
sb->sb_csum = calc_sb0_csum(sb);
diff -up mdadm-3.2.2/super1.c.writemostly mdadm-3.2.2/super1.c
--- mdadm-3.2.2/super1.c.writemostly 2011-06-17 01:15:50.000000000 -0400
+++ mdadm-3.2.2/super1.c 2011-07-27 14:12:18.656889548 -0400
@@ -803,6 +803,10 @@ static int update_super1(struct supertyp
__le64_to_cpu(sb->data_size));
} else if (strcmp(update, "_reshape_progress")==0)
sb->reshape_position = __cpu_to_le64(info->reshape_progress);
+ else if (strcmp(update, "writemostly")==0)
+ sb->devflags |= WriteMostly1;
+ else if (strcmp(update, "readwrite")==0)
+ sb->devflags &= ~WriteMostly1;
else
rv = -1;
@@ -923,6 +927,7 @@ static int add_to_super1(struct supertyp
sb->max_dev = __cpu_to_le32(dk->number+1);
sb->dev_number = __cpu_to_le32(dk->number);
+ sb->devflags = 0; /* don't copy another disks flags */
sb->sb_csum = calc_sb_1_csum(sb);
dip = (struct devinfo **)&st->info;
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