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-rw-r--r--Documentation/md.txt29
1 files changed, 23 insertions, 6 deletions
diff --git a/Documentation/md.txt b/Documentation/md.txt
index f0eee83ff78..fc94770f44a 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.
@@ -419,7 +423,6 @@ Each directory contains:
written, it will be rejected.
recovery_start
-
When the device is not 'in_sync', this records the number of
sectors from the start of the device which are known to be
correct. This is normally zero, but during a recovery
@@ -435,6 +438,20 @@ Each directory contains:
Setting this to 'none' is equivalent to setting 'in_sync'.
Setting to any other value also clears the 'in_sync' flag.
+ bad_blocks
+ This gives the list of all known bad blocks in the form of
+ start address and length (in sectors respectively). If output
+ is too big to fit in a page, it will be truncated. Writing
+ "sector length" to this file adds new acknowledged (i.e.
+ recorded to disk safely) bad blocks.
+
+ unacknowledged_bad_blocks
+ This gives the list of known-but-not-yet-saved-to-disk bad
+ blocks in the same form of 'bad_blocks'. If output is too big
+ to fit in a page, it will be truncated. Writing to this file
+ adds bad blocks without acknowledging them. This is largely
+ for testing.
+
An active md device will also contain and entry for each active device