md: allow reshape_position for md arrays to be set via sysfs
"reshape_position" records how much progress has been made on a "reshape"
(adding drives, changing layout or chunksize).
When it is set, the number of drives, layout and chunksize can have
two possible values, an old an a new.
So allow these different values to be visible, and allow both old and new to
be set: Set the old ones first, then the reshape_position, then the new
values.
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/Documentation/md.txt b/Documentation/md.txt
index 2202f5d..5818628 100644
--- a/Documentation/md.txt
+++ b/Documentation/md.txt
@@ -178,6 +178,21 @@
The size should be at least PAGE_SIZE (4k) and should be a power
of 2. This can only be set while assembling an array
+ layout
+ The "layout" for the array for the particular level. This is
+ simply a number that is interpretted differently by different
+ levels. It can be written while assembling an array.
+
+ reshape_position
+ This is either "none" or a sector number within the devices of
+ the array where "reshape" is up to. If this is set, the three
+ attributes mentioned above (raid_disks, chunk_size, layout) can
+ potentially have 2 values, an old and a new value. If these
+ values differ, reading the attribute returns
+ new (old)
+ and writing will effect the 'new' value, leaving the 'old'
+ unchanged.
+
component_size
For arrays with data redundancy (i.e. not raid0, linear, faulty,
multipath), all components must be the same size - or at least
@@ -193,11 +208,6 @@
1.2 (newer format in varying locations) or "none" indicating that
the kernel isn't managing metadata at all.
- layout
- The "layout" for the array for the particular level. This is
- simply a number that is interpretted differently by different
- levels. It can be written while assembling an array.
-
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
@@ -259,29 +269,6 @@
like active, but no writes have been seen for a while (safe_mode_delay).
- sync_speed_min
- sync_speed_max
- This are similar to /proc/sys/dev/raid/speed_limit_{min,max}
- however they only apply to the particular array.
- If no value has been written to these, of if the word 'system'
- is written, then the system-wide value is used. If a value,
- in kibibytes-per-second is written, then it is used.
- When the files are read, they show the currently active value
- followed by "(local)" or "(system)" depending on whether it is
- a locally set or system-wide value.
-
- sync_completed
- This shows the number of sectors that have been completed of
- whatever the current sync_action is, followed by the number of
- sectors in total that could need to be processed. The two
- numbers are separated by a '/' thus effectively showing one
- value, a fraction of the process that is complete.
-
- sync_speed
- This shows the current actual speed, in K/sec, of the current
- sync_action. It is averaged over the last 30 seconds.
-
-
As component devices are added to an md array, they appear in the 'md'
directory as new directories named
dev-XXX
@@ -412,6 +399,35 @@
Note that the numbers are 'bit' numbers, not 'block' numbers.
They should be scaled by the bitmap_chunksize.
+ sync_speed_min
+ sync_speed_max
+ This are similar to /proc/sys/dev/raid/speed_limit_{min,max}
+ however they only apply to the particular array.
+ If no value has been written to these, of if the word 'system'
+ is written, then the system-wide value is used. If a value,
+ in kibibytes-per-second is written, then it is used.
+ When the files are read, they show the currently active value
+ followed by "(local)" or "(system)" depending on whether it is
+ a locally set or system-wide value.
+
+ sync_completed
+ This shows the number of sectors that have been completed of
+ whatever the current sync_action is, followed by the number of
+ sectors in total that could need to be processed. The two
+ numbers are separated by a '/' thus effectively showing one
+ value, a fraction of the process that is complete.
+
+ sync_speed
+ This shows the current actual speed, in K/sec, of the current
+ sync_action. It is averaged over the last 30 seconds.
+
+ suspend_lo
+ suspend_hi
+ The two values, given as numbers of sectors, indicate a range
+ within the array where IO will be blocked. This is currently
+ only supported for raid4/5/6.
+
+
Each active md device may also have attributes specific to the
personality module that manages it.
These are specific to the implementation of the module and could