md: update documentation for md/rdev/state sysfs interface

Previous patches in the bad block series extended behavior of
rdev's 'state' interface but lacked documentation update.
Fix it.

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

1 files changed, 9 insertions, 5 deletions

diff --git a/Documentation/md.txt b/Documentation/md.txt
index 923a6bddce7c..fc94770f44ab 100644
--- a/Documentation/md.txt
+++ b/Documentation/md.txt
@@ -360,18 +360,20 @@ Each directory contains:
         A file recording the current state of the device in the array
         which can be a comma separated list of
               faulty   - device has been kicked from active use due to
-                         a detected fault
+                         a detected fault or it has unacknowledged bad
+                         blocks
               in_sync  - device is a fully in-sync member of the array
               writemostly - device will only be subject to read
                          requests if there are no other options.
                          This applies only to raid1 arrays.
-              blocked  - device has failed, metadata is "external",
-                         and the failure hasn't been acknowledged yet.
+              blocked  - device has failed, and the failure hasn't been
+                         acknowledged yet by the metadata handler.
                          Writes that would write to this device if
                          it were not faulty are blocked.
               spare    - device is working, but not a full member.
                          This includes spares that are in the process
                          of being recovered to
+              write_error - device has ever seen a write error.
         This list may grow in future.
         This can be written to.
         Writing "faulty"  simulates a failure on the device.
@@ -379,9 +381,11 @@ Each directory contains:
         Writing "writemostly" sets the writemostly flag.
         Writing "-writemostly" clears the writemostly flag.
         Writing "blocked" sets the "blocked" flag.
-        Writing "-blocked" clears the "blocked" flag and allows writes
-                to complete.
+        Writing "-blocked" clears the "blocked" flags and allows writes
+                to complete and possibly simulates an error.
         Writing "in_sync" sets the in_sync flag.
+        Writing "write_error" sets writeerrorseen flag.
+        Writing "-write_error" clears writeerrorseen flag.
 
         This file responds to select/poll. Any change to 'faulty'
         or 'blocked' causes an event.