[PATCH] md: make /proc/mdstat pollable

With this patch it is possible to poll /proc/mdstat to detect arrays appearing
or disappearing, to detect failures, recovery starting, recovery com

[PATCH] md: make /proc/mdstat pollable

With this patch it is possible to poll /proc/mdstat to detect arrays appearing
or disappearing, to detect failures, recovery starting, recovery completing,
and devices being added and removed.

It is similar to the poll-ability of /proc/mounts, though different in that:

We always report that the file is readable (because face it, it is, even if
only for EOF).

We report POLLPRI when there is a change so that select() can detect
it as an exceptional event. Not only are these exceptional events, but
that is the mechanism that the current 'mdadm' uses to watch for events
(It also polls after a timeout).
(We also report POLLERR like /proc/mounts).

Finally, we only reset the per-file event counter when the start of the file
is read, rather than when poll() returns an event. This is more robust as it
means that an fd will continue to report activity to poll/select until the
program clearly responds to that activity.

md_new_event takes an 'mddev' which isn't currently used, but it will be soon.

Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

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[PATCH] md: attempt to auto-correct read errors in raid1

On a read-error we suspend the array, then synchronously read the block from
other arrays until we find one where we can read it.

[PATCH] md: attempt to auto-correct read errors in raid1

On a read-error we suspend the array, then synchronously read the block from
other arrays until we find one where we can read it. Then we try writing the
good data back everywhere and make sure it works. If any write or subsequent
read fails, only then do we fail the device out of the array.

To be able to suspend the array, we need to also keep track of how many
requests are queued for handling by raid1d.

Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

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[PATCH] md: write intent bitmap support for raid10

Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl

[PATCH] md: write intent bitmap support for raid10

Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

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[PATCH] md: move bitmap_create to after md array has been initialised

This is important because bitmap_create uses
mddev->resync_max_sectors
and that doesn't have a valid value unt

[PATCH] md: move bitmap_create to after md array has been initialised

This is important because bitmap_create uses
mddev->resync_max_sectors
and that doesn't have a valid value until after the array
has been initialised (with pers->run()).
[It doesn't make a difference for current personalities that
support bitmaps, but will make a difference for raid10]

This has the added advantage of meaning with can move the thread->timeout
manipulation inside the bitmap.c code instead of sprinkling identical code
throughout all personalities.

Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

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[PATCH] md: allow dirty raid[456] arrays to be started at boot

See patch to md.txt for more details

Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@

[PATCH] md: allow dirty raid[456] arrays to be started at boot

See patch to md.txt for more details

Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

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[PATCH] md: Change case of raid level reported in sys/mdX/md/level

I had thought that keeping the reported tail level clearly different
from the module name was a good idea, but I've cha

[PATCH] md: Change case of raid level reported in sys/mdX/md/level

I had thought that keeping the reported tail level clearly different
from the module name was a good idea, but I've changed my mind.

'raid5' is better and probably less confusing than 'RAID-5'.

Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

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[PATCH] md: set default_bitmap_offset properly in set_array_info

If an array is created using set_array_info, default_bitmap_offset isn't set
properly meaning that an internal bitmap can

[PATCH] md: set default_bitmap_offset properly in set_array_info

If an array is created using set_array_info, default_bitmap_offset isn't set
properly meaning that an internal bitmap cannot be hot-added until the array
is stopped and re-assembled.

Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

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[PATCH] md: fix is_mddev_idle calculation now that disk/sector accounting happens when request completes

md needs to monitor the rate of requests to its devices when doing
resync/recover

[PATCH] md: fix is_mddev_idle calculation now that disk/sector accounting happens when request completes

md needs to monitor the rate of requests to its devices when doing
resync/recovery so that it can back-off when there is non-resync IO. It
does this by comparing resync IO, which it counts, with total IO which is
taken from disk_stats.

disk_stats were recently changed to account sectors when a request
completes instead of when it is queued. This upsets md's calculations.

We could do the sync_io accounting at the end of requests too, but that has
problems. If an underlying device is an md array, the accounting will
still be done when the request is submitted. This could be changed for
some raid levels, but it cannot be changed for raid0 or linear without
substantial code changes.

So instead, we increase the error that is_mddev_idle allows, up to the
maximum amount of resync IO that can be in flight at any time. The
calculation is current fragile as each personality as different limits for
in-flight resync. This should be fixed up.

For now, this simple patch fixes the problem.

Increasing the error margin decreases the sensitivity to non-resync IO. To
partially compensate for this, the time to wait when non-resync IO is
detected is increased so that less steady IO is required to keep the resync
at bay.

Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

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[PATCH] md: make md threads interruptible again

Despite the fact that md threads don't need to be signalled, and won't
respond to signals anyway, we need to have an 'interruptible' wait,

[PATCH] md: make md threads interruptible again

Despite the fact that md threads don't need to be signalled, and won't
respond to signals anyway, we need to have an 'interruptible' wait, else
they stay in 'D' state and add to the load average.

(akpm: the signal_pending() test is unneeded - we'll fix that up in the next
round. For now, leave it there because that's how the code used to be).

Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

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[PATCH] md: mark START_ARRAY deprecated with a date

This was marked deprecated "after 2.6" back in the 2.5 days. But now it
seems there isn't going to be any "after 2.6", and we depreca

[PATCH] md: mark START_ARRAY deprecated with a date

This was marked deprecated "after 2.6" back in the 2.5 days. But now it
seems there isn't going to be any "after 2.6", and we deprecate by date
now. So set a date.

Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

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[PATCH] md: document sysfs usage of md, and make a couple of small refinements

Document in Documentation/md.txt the files that now appear in sysfs, and make
a couple of small refinements

[PATCH] md: document sysfs usage of md, and make a couple of small refinements

Document in Documentation/md.txt the files that now appear in sysfs, and make
a couple of small refinements to exactly when 'level' and 'raid_disks' are
empty, to make it match the documentation.

Signed-off-by: Neil Brown <neilb@suse.de>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

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[PATCH] md: improve 'scan_mode' and rename it to 'sync_action'

The current sync_action for an array can be one of

idle - nothing happening
resync - reduncancy being recal

[PATCH] md: improve 'scan_mode' and rename it to 'sync_action'

The current sync_action for an array can be one of

idle - nothing happening
resync - reduncancy being recalcualted
recover - missing device being recoverred to spare
check - user initiated check of redundancy
repair - like resync but user-initiated and ignores
bitmap optimisation.

Each of these strings can also be written to the 'sync_action' file to cause
that action to happen (if appropriate).

While 'sync' is not technically correct, as a recovery is *not* a 'sync', I
think it is the most servicable word here. Also 'action' is a strong word
than 'mode'.

Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

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[PATCH] md: complete conversion of md to use kthreads

There are a few loose ends following the conversion of md to use kthreads:

- Some fields in mdk_thread_t that aren't needed (kt

[PATCH] md: complete conversion of md to use kthreads

There are a few loose ends following the conversion of md to use kthreads:

- Some fields in mdk_thread_t that aren't needed (kthreads does it's own
completion and manages it's own name).

- thread->run is now never NULL, so no need to check

- Some tests for signal_pending that aren't needed (As we don't use signals
to stop threads any more)

- Some flush_signals are not needed

- Some waits are interruptible and don't need to be.

Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

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[PATCH] md: ignore auto-readonly flag for arrays where it isn't meaningful

The 'auto-readonly' flag (which suppresses resync and superblock updates until
the first write) is not meaningf

[PATCH] md: ignore auto-readonly flag for arrays where it isn't meaningful

The 'auto-readonly' flag (which suppresses resync and superblock updates until
the first write) is not meaningful for personalities that don't support resync
or superblock writes (raid0, linear, etc).

So clear the setting early to avoid it confusing anything - e.g. appearing in
/proc/mdstat

Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

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[PATCH] md: only try to print recovery/resync status for personalities that support recovery

The introduction of 'resync=PENDING' (for read-only devices) caused that
message to appear fo

[PATCH] md: only try to print recovery/resync status for personalities that support recovery

The introduction of 'resync=PENDING' (for read-only devices) caused that
message to appear for non-syncable arrays like raid0 and linear. Simplest
thing is to not try to print any resync info unless the personality clearly
supports it.

Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

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[PATCH] md: split off some md attributes in sysfs to a separate group

Some, but not all, md array support data redundancy and hence support checking
and restoring that redundancy (resync

[PATCH] md: split off some md attributes in sysfs to a separate group

Some, but not all, md array support data redundancy and hence support checking
and restoring that redundancy (resync, rebuild).

Some attributes apply specifically to functions involving this redundancy, and
so should only appear for md arrays for which they are meaningful. i.e. they
should not appear for raid0, linear, multpath, faulty.

This patch separates these into a distinct group and creates the group only if
the personality supports sync_request.

Signed-off-by: Neil Brown <neilb@suse.de>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

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[PATCH] md: fix some locking and module refcounting issues with md's use of sysfs

1/ I really should be using the __ATTR macros for defining attributes, so
that the .owner field get s

[PATCH] md: fix some locking and module refcounting issues with md's use of sysfs

1/ I really should be using the __ATTR macros for defining attributes, so
that the .owner field get set properly, otherwise modules can be removed
while sysfs files are open. This also involves some name changes of _show
routines.

2/ Always lock the mddev (against reconfiguration) for all sysfs attribute
access. This easily avoid certain races and is completely consistant with
other interfaces (ioctl and /proc/mdstat both always lock against
reconfiguration).

3/ raid5 attributes must check that the 'conf' structure actually exists
(the array could have been stopped while an attribute file was open).

4/ A missing 'kfree' from when the raid5_conf_t was converted to have a
kobject embedded, and then converted back again.

Signed-off-by: Neil Brown <neilb@suse.de>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

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[PATCH] md: make sure /block link in /sys/.../md/ goes to correct devices

If a block_device is a partition, then it's kobject is
bdev->bd_part->kobj
otherwise (if it is a full devi

[PATCH] md: make sure /block link in /sys/.../md/ goes to correct devices

If a block_device is a partition, then it's kobject is
bdev->bd_part->kobj
otherwise (if it is a full device), the kobject is
bdev->bd_disk->kobj

As md wants back-links to the correct object (whether partition or not), we
need to respect this difference... (Thus current code shows a link to the
whole device, whether we are using a partition or not, which is wrong).

Signed-off-by: Neil Brown <neilb@suse.de>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

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[PATCH] md: allow md arrays to be started read-only (module parameter).

When an md array is started, the superblock will be written, and resync may
commense. This is not good if you wan

[PATCH] md: allow md arrays to be started read-only (module parameter).

When an md array is started, the superblock will be written, and resync may
commense. This is not good if you want to be completely read-only as, for
example, when preparing to resume from a suspend-to-disk image.

So introduce a module parameter "start_ro" which can be set
to '1' at boot, at module load, or via
/sys/module/md_mod/parameters/start_ro

When this is set, new arrays get an 'auto-ro' mode, which disables all
internal io (superblock updates, resync, recovery) and is automatically
switched to 'rw' when the first write request arrives.

The array can be set to true 'ro' mode using 'mdadm -r' before the first
write request, or resync can be started without a write using 'mdadm -w'.

Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

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[PATCH] md: Remove attempt to use dynamic names in sysfs for component devices on an MD array.

With version-0.90 superblock, component devices on an md device to not have
any stable name

[PATCH] md: Remove attempt to use dynamic names in sysfs for component devices on an MD array.

With version-0.90 superblock, component devices on an md device to not have
any stable name related to the array -(version-1 assigns a fixed index when
a device is added to an array, and this remains despit any hot-swap).

The intial code for making these devices appear in sysfs used dynamic
names, which would change whenever a hot-spare was swapped for a failed or
missing device. This turns out not to be practical in sysfs for a number
of reasons.

This patch changes then naming of component devices to be based on the
result of 'bdevname'. This is stable and should be unique.

Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

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[PATCH] md: support BIO_RW_BARRIER for md/raid1

We can only accept BARRIER requests if all slaves handle
barriers, and that can, of course, change with time....

So we keep track

[PATCH] md: support BIO_RW_BARRIER for md/raid1

We can only accept BARRIER requests if all slaves handle
barriers, and that can, of course, change with time....

So we keep track of whether the whole array seems safe for barriers,
and also whether each individual rdev handles barriers.

We initially assumes barriers are OK.

When writing the superblock we try a barrier, and if that fails, we flag
things for no-barriers. This will usually clear the flags fairly quickly.

If writing the superblock finds that BIO_RW_BARRIER is -ENOTSUPP, we need to
resubmit, so introduce function "md_super_wait" which waits for requests to
finish, and retries ENOTSUPP requests without the barrier flag.

When writing the real raid1, write requests which were BIO_RW_BARRIER but
which aresn't supported need to be retried. So raid1d is enhanced to do this,
and when any bio write completes (i.e. no retry needed) we remove it from the
r1bio, so that devices needing retry are easy to find.

We should hardly ever get -ENOTSUPP errors when writing data to the raid.
It should only happen if:
1/ the device used to support BARRIER, but now doesn't. Few devices
change like this, though raid1 can!
or
2/ the array has no persistent superblock, so there was no opportunity to
pre-test for barriers when writing the superblock.

Signed-off-by: Neil Brown <neilb@cse.unsw.edu.au>
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

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[PATCH] md: make md on-disk bitmaps not host-endian

Current bitmaps use set_bit et.al and so are host-endian, which means
not-portable. Oops.

Define a new version number (4) fo

[PATCH] md: make md on-disk bitmaps not host-endian

Current bitmaps use set_bit et.al and so are host-endian, which means
not-portable. Oops.

Define a new version number (4) for which bitmaps are little-endian.

Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

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[PATCH] md: convert 'faulty' and 'in_sync' fields to bits in 'flags' field

This has the advantage of removing the confusion caused by 'rdev_t' and
'mddev_t' both having 'in_sync' fields.

[PATCH] md: convert 'faulty' and 'in_sync' fields to bits in 'flags' field

This has the advantage of removing the confusion caused by 'rdev_t' and
'mddev_t' both having 'in_sync' fields.

Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

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[PATCH] md: improvements to raid5 handling of read errors

Two refinements to the 'attempt-overwrite-on-read-error' mechanism.
1/ If the array is read-only, don't attempt an over-write.

[PATCH] md: improvements to raid5 handling of read errors

Two refinements to the 'attempt-overwrite-on-read-error' mechanism.
1/ If the array is read-only, don't attempt an over-write.
2/ If there are more than max_nr_stripes read errors on a device with
no success, fail the drive. This will make sure a dead
drive will be eventually kicked even when we aren't trying
to rewrite (which would normally kick a dead drive more quickly.

Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

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[PATCH] md: change raid5 sysfs attribute to not create a new directory

There isn't really a need for raid5 attributes to be an a subdirectory,
so this patch moves them from
/sys/bl

[PATCH] md: change raid5 sysfs attribute to not create a new directory

There isn't really a need for raid5 attributes to be an a subdirectory,
so this patch moves them from
/sys/block/mdX/md/raid5/attribute
to
/sys/block/mdX/md/attribute

This suggests that all md personalities should co-operate about
namespace usage, but that shouldn't be a problem.

Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

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