md: add 'write_error' flag to component devices.

If a device has ever seen a write error, we will want to handle
known-bad-blocks differently.
So create an appropriate state flag and export it via sysfs.

Signed-off-by: NeilBrown <neilb@suse.de>
Reviewed-by: Namhyung Kim <namhyung@gmail.com>

2 files changed, 15 insertions, 0 deletions

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 48217e8aa0e..1520d18c5af 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -2516,6 +2516,10 @@ state_show(mdk_rdev_t *rdev, char *page)
                 len += sprintf(page+len, "%sspare", sep);
                 sep = ",";
         }
+        if (test_bit(WriteErrorSeen, &rdev->flags)) {
+                len += sprintf(page+len, "%swrite_error", sep);
+                sep = ",";
+        }
         return len+sprintf(page+len, "\n");
 }
 
@@ -2530,6 +2534,8 @@ state_store(mdk_rdev_t *rdev, const char *buf, size_t len)
          *  blocked - sets the Blocked flag
          *  -blocked - clears the Blocked flag
          *  insync - sets Insync providing device isn't active
+         *  write_error - sets WriteErrorSeen
+         *  -write_error - clears WriteErrorSeen
          */
         int err = -EINVAL;
         if (cmd_match(buf, "faulty") && rdev->mddev->pers) {
@@ -2565,6 +2571,12 @@ state_store(mdk_rdev_t *rdev, const char *buf, size_t len)
         } else if (cmd_match(buf, "insync") && rdev->raid_disk == -1) {
                 set_bit(In_sync, &rdev->flags);
                 err = 0;
+        } else if (cmd_match(buf, "write_error")) {
+                set_bit(WriteErrorSeen, &rdev->flags);
+                err = 0;
+        } else if (cmd_match(buf, "-write_error")) {
+                clear_bit(WriteErrorSeen, &rdev->flags);
+                err = 0;
         }
         if (!err)
                 sysfs_notify_dirent_safe(rdev->sysfs_state);
diff --git a/drivers/md/md.h b/drivers/md/md.h
index 7c3192c0a29..fa4b607854a 100644
--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -84,6 +84,9 @@ struct mdk_rdev_s
 #define Blocked         8               /* An error occurred on an externally
                                          * managed array, don't allow writes
                                          * until it is cleared */
+#define WriteErrorSeen  9               /* A write error has been seen on this
+                                         * device
+                                         */
         wait_queue_head_t blocked_wait;
 
         int desc_nr;                    /* descriptor index in the superblock */