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  1. 11 May, 2011 16 commits
    • NeilBrown's avatar
      md: allow resync_start to be set while an array is active. · b098636c
      NeilBrown authored 
      The sysfs attribute 'resync_start' (known internally as recovery_cp),
records where a resync is up to.  A value of 0 means the array is
not known to be in-sync at all.  A value of MaxSector means the array
is believed to be fully in-sync.

When the size of member devices of an array (RAID1,RAID4/5/6) is
increased, the array can be increased to match.  This process sets
resync_start to the old end-of-device offset so that the new part of
the array gets resynced.

However with RAID1 (and RAID6) a resync is not technically necessary
and may be undesirable.  So it would be good if the implied resync
after the array is resized could be avoided.

So: change 'resync_start' so the value can be changed while the array
is active, and as a precaution only allow it to be changed while
resync/recovery is 'frozen'.  Changing it once resync has started is
not going to be useful anyway.

This allows the array to be resized without a resync by:
  write 'frozen' to 'sync_action'
  write new size to 'component_size' (this will set resync_start)
  write 'none' to 'resync_start'
  write 'idle' to 'sync_action'.

Also slightly improve some tests on recovery_cp when resizing
raid1/raid5.  Now that an arbitrary value could be set we should be
more careful in our tests.
Signed-off-by: default avatarNeilBrown <neilb@suse.de>
      b098636c
    • NeilBrown's avatar
      md/raid10: reformat some loops with less indenting. · ab9d47e9
      NeilBrown authored 
      When a loop ends with an 'if' with a large body, it is neater
to make the if 'continue' on the inverse condition, and then
the body is indented less.

Apply this pattern 3 times, and wrap some other long lines.
Signed-off-by: default avatarNeilBrown <neilb@suse.de>
      ab9d47e9
    • NeilBrown's avatar
      md/raid10: remove unused variable. · f17ed07c
      NeilBrown authored 
      This variable 'disk' is never used - how odd.
Signed-off-by: default avatarNeilBrown <neilb@suse.de>
      f17ed07c
    • NeilBrown's avatar
      md/raid10: make more use of 'slot' in raid10d. · a8830bca
      NeilBrown authored 
      Now that we have a 'slot' variable, make better use of it to simplify
some code a little.
Signed-off-by: default avatarNeilBrown <neilb@suse.de>
      a8830bca
    • NeilBrown's avatar
      md/raid10: some tidying up in fix_read_error · 7c4e06ff
      NeilBrown authored 
      Currently the rdev on which a read error happened could be removed
before we perform the fix_error handling.  This requires extra tests
for NULL.

So delay the rdev_dec_pending call until after the call to
fix_read_error so that we can be sure that the rdev still exists.

This allows an 'if' clause to be removed so the body gets re-indented
back one level.
Signed-off-by: default avatarNeilBrown <neilb@suse.de>
      7c4e06ff
    • NeilBrown's avatar
      md/raid1: improve handling of pages allocated for write-behind. · af6d7b76
      NeilBrown authored 
      The current handling and freeing of these pages is a bit fragile.
We only keep the list of allocated pages in each bio, so we need to
still have a valid bio when freeing the pages, which is a bit clumsy.

So simply store the allocated page list in the r1_bio so it can easily
be found and freed when we are finished with the r1_bio.
Signed-off-by: default avatarNeilBrown <neilb@suse.de>
      af6d7b76
    • NeilBrown's avatar
      md/raid1: try fix_sync_read_error before process_checks. · 7ca78d57
      NeilBrown authored 
      If we get a read error during resync/recovery we current repeat with
single-page reads to find out just where the error is, and possibly
read each page from a different device.

With check/repair we don't currently do that, we just fail.
However it is possible that while all devices fail on the large 64K
read, we might be able to satisfy each 4K from one device or another.

So call fix_sync_read_error before process_checks to maximise the
chance of finding good data and writing it out to the devices with
read errors.

For this to work, we need to set the 'uptodate' flags properly after
fix_sync_read_error has succeeded.
Signed-off-by: default avatarNeilBrown <neilb@suse.de>
      7ca78d57
    • NeilBrown's avatar
      md/raid1: tidy up new functions: process_checks and fix_sync_read_error. · 78d7f5f7
      NeilBrown authored 
      These changes are mostly cosmetic:

1/ change mddev->raid_disks to conf->raid_disks because the later is
   technically safer, though in current practice it doesn't matter in
   this particular context.
2/ Rearrange two for / if loops to have an early 'continue' so the
   body of the 'if' doesn't need to be indented so much.
Signed-off-by: default avatarNeilBrown <neilb@suse.de>
      78d7f5f7
    • NeilBrown's avatar
      md/raid1: split out two sub-functions from sync_request_write · a68e5870
      NeilBrown authored 
      sync_request_write is too big and too deep.
So split out two self-contains bits of functionality into separate
function.
Signed-off-by: default avatarNeilBrown <neilb@suse.de>
      a68e5870
    • NeilBrown's avatar
      md: make error_handler functions more uniform and correct. · 6f8d0c77
      NeilBrown authored 
      - there is no need to test_bit Faulty, as that was already done in
  md_error which is the only caller of these functions.
- MD_CHANGE_DEVS should be set *after* faulty is set to ensure
  metadata is updated correctly.
- spinlock should be held while updating ->degraded.
Signed-off-by: default avatarNeilBrown <neilb@suse.de>
      6f8d0c77
    • NeilBrown's avatar
      md/multipath: discard ->working_disks in favour of ->degraded · 92f861a7
      NeilBrown authored 
      conf->working_disks duplicates information already available
in mddev->degraded.
So remove working_disks.
Signed-off-by: default avatarNeilBrown <neilb@suse.de>
      92f861a7
    • NeilBrown's avatar
      md/raid1: clean up read_balance. · 76073054
      NeilBrown authored 
      read_balance has two loops which both look for a 'best'
device based on slightly different criteria.
This is clumsy and makes is hard to add extra criteria.

So replace it all with a single loop that combines everything.
Signed-off-by: default avatarNeilBrown <neilb@suse.de>
      76073054
    • NeilBrown's avatar
      md: simplify raid10 read_balance · 56d99121
      NeilBrown authored 
      raid10 read balance has two different loop for looking through
possible devices to chose the best.
Collapse those into one loop and generally make the code more
readable.
Signed-off-by: default avatarNeilBrown <neilb@suse.de>
      56d99121
    • NeilBrown's avatar
      md/bitmap: fix saving of events_cleared and other state. · 8258c532
      NeilBrown authored 
      If a bitmap is found to be 'stale' the events_cleared value
is set to match 'events'.
However if the array is degraded this does not get stored on disk.
This can subsequently lead to incorrect behaviour.

So change bitmap_update_sb to always update events_cleared in the
superblock from the known events_cleared.
For neatness also set ->state from ->flags.
This requires updating ->state whenever we update ->flags, which makes
sense anyway.

This is suitable for any active -stable release.

cc: stable@kernel.org
Signed-off-by: default avatarNeilBrown <neilb@suse.de>
      8258c532
    • NeilBrown's avatar
      md: reject a re-add request that cannot be honoured. · bedd86b7
      NeilBrown authored 
      The 'add_new_disk' ioctl can be used to add a device either as a
spare, or as an active disk that just needs to be resynced based on
write-intent-bitmap information (re-add)

Currently if a re-add is requested but fails we add as a spare
instead.  This makes it impossible for user-space to check for
failure.

So change to require that a re-add attempt will either succeed or
completely fail.  User-space can then decide what to do next.
Signed-off-by: default avatarNeilBrown <neilb@suse.de>
      bedd86b7
    • NeilBrown's avatar
      md: Fix race when creating a new md device. · b0140891
      NeilBrown authored 
      There is a race when creating an md device by opening /dev/mdXX.

If two processes do this at much the same time they will follow the
call path
  __blkdev_get -> get_gendisk -> kobj_lookup

The first will call
  -> md_probe -> md_alloc -> add_disk -> blk_register_region

and the race happens when the second gets to kobj_lookup after
add_disk has called blk_register_region but before it returns to
md_alloc.

In the case the second will not call md_probe (as the probe is already
done) but will get a handle on the gendisk, return to __blkdev_get
which will then call md_open (via the ->open) pointer.

As mddev->gendisk hasn't been set yet, md_open will think something is
wrong an return with ERESTARTSYS.

This can loop endlessly while the first thread makes no progress
through add_disk.  Nothing is blocking it, but due to scheduler
behaviour it doesn't get a turn.
So this is essentially a live-lock.

We fix this by simply moving the assignment to mddev->gendisk before
the call the add_disk() so md_open doesn't get confused.
Also move blk_queue_flush earlier because add_disk should be as late
as possible.

To make sure that md_open doesn't complete until md_alloc has done all
that is needed, we take mddev->open_mutex during the last part of
md_alloc.  md_open will wait for this.

This can cause a lock-up on boot so Cc:ing for stable.
For 2.6.36 and earlier a different patch will be needed as the
'blk_queue_flush' call isn't there.
Signed-off-by: default avatarNeilBrown <neilb@suse.de>
Reported-by: default avatarThomas Jarosch <thomas.jarosch@intra2net.com>
Tested-by: default avatarThomas Jarosch <thomas.jarosch@intra2net.com>
Cc: stable@kernel.org
      b0140891
  3. 10 May, 2011 2 commits
  5. 09 May, 2011 22 commits
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