md: add 'recovery_start' per-device sysfs attribute
Enable external metadata arrays to manage rebuild checkpointing via a
md/dev-XXX/recovery_start attribute which reflects rdev->recovery_offset
Also update resync_start_store to allow 'none' to be written, for
consistency.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: NeilBrown <neilb@suse.de>
diff --git a/Documentation/md.txt b/Documentation/md.txt
index 21d26fb..188f476 100644
--- a/Documentation/md.txt
+++ b/Documentation/md.txt
@@ -233,9 +233,9 @@
resync_start
The point at which resync should start. If no resync is needed,
- this will be a very large number. At array creation it will
- default to 0, though starting the array as 'clean' will
- set it much larger.
+ this will be a very large number (or 'none' since 2.6.30-rc1). At
+ array creation it will default to 0, though starting the array as
+ 'clean' will set it much larger.
new_dev
This file can be written but not read. The value written should
@@ -379,8 +379,9 @@
Writing "writemostly" sets the writemostly flag.
Writing "-writemostly" clears the writemostly flag.
Writing "blocked" sets the "blocked" flag.
- Writing "-blocked" clear the "blocked" flag and allows writes
+ Writing "-blocked" clears the "blocked" flag and allows writes
to complete.
+ Writing "in_sync" sets the in_sync flag.
This file responds to select/poll. Any change to 'faulty'
or 'blocked' causes an event.
@@ -417,6 +418,24 @@
array. If a value less than the current component_size is
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
+ operation is will steadily increase, and if the recovery is
+ interrupted, restoring this value can cause recovery to
+ avoid repeating the earlier blocks. With v1.x metadata, this
+ value is saved and restored automatically.
+
+ This can be set whenever the device is not an active member of
+ the array, either before the array is activated, or before
+ the 'slot' is set.
+
+ Setting this to 'none' is equivalent to setting 'in_sync'.
+ Setting to any other value also clears the 'in_sync' flag.
+
+
An active md device will also contain and entry for each active device
in the array. These are named
