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  1. 16 10月, 2009 1 次提交
  3. 23 9月, 2009 1 次提交
  5. 26 5月, 2009 1 次提交
    • N
      md: bitmap: improve bitmap maintenance code. · be512691
      由 NeilBrown 提交于 
      The code for checking which bits in the bitmap can be cleared
has 2 problems:
 1/ it repeatedly takes and drops a spinlock, where it would make
    more sense to just hold on to it most of the time.
 2/ it doesn't make use of some opportunities to skip large sections
    of the bitmap

This patch fixes those.  It will only affect CPU consumption, not
correctness.
Signed-off-by: NNeilBrown <neilb@suse.de>
      be512691
  7. 23 5月, 2009 1 次提交
  9. 07 5月, 2009 2 次提交
    • N
      md: fix some (more) errors with bitmaps on devices larger than 2TB. · db305e50
      由 NeilBrown 提交于 
      If a write intent bitmap covers more than 2TB, we sometimes work with
values beyond 32bit, so these need to be sector_t.  This patches
add the required casts to some unsigned longs that are being shifted
up.

This will affect any raid10 larger than 2TB, or any raid1/4/5/6 with
member devices that are larger than 2TB.
Signed-off-by: NNeilBrown <neilb@suse.de>
Reported-by: N"Mario 'BitKoenig' Holbe" <Mario.Holbe@TU-Ilmenau.DE>
Cc: stable@kernel.org
      db305e50
    • N
      md: fix loading of out-of-date bitmap. · b74fd282
      由 NeilBrown 提交于 
      When md is loading a bitmap which it knows is out of date, it fills
each page with 1s and writes it back out again.  However the
write_page call makes used of bitmap->file_pages and
bitmap->last_page_size which haven't been set correctly yet.  So this
can sometimes fail.

Move the setting of file_pages and last_page_size to before the call
to write_page.

This bug can cause the assembly on an array to fail, thus making the
data inaccessible.  Hence I think it is a suitable candidate for
-stable.

Cc: stable@kernel.org
Reported-by: NVojtech Pavlik <vojtech@suse.cz>
Signed-off-by: NNeilBrown <neilb@suse.de>
      b74fd282
  11. 20 4月, 2009 1 次提交
  13. 14 4月, 2009 1 次提交
    • N
      md: improve usefulness and accuracy of sysfs file md/sync_completed. · acb180b0
      由 NeilBrown 提交于 
      The sync_completed file reports how much of a resync (or recovery or
reshape) has been completed.
However due to the possibility of out-of-order completion of writes,
it is not certain to be accurate.

We have an internal value - mddev->curr_resync_completed - which is an
accurate value (though it might not always be quite so uptodate).

So:
 - make curr_resync_completed be uptodate a little more often,
   particularly when raid5 reshape updates status in the metadata
 - report curr_resync_completed in the sysfs file
 - allow poll/select to report all updates to md/sync_completed.

This makes sync_completed completed usable by any external metadata
handler that wants to record this status information in its metadata.
Signed-off-by: NNeilBrown <neilb@suse.de>
      acb180b0
  15. 31 3月, 2009 8 次提交
    • A
      md: Make mddev->size sector-based. · 58c0fed4
      由 Andre Noll 提交于 
      This patch renames the "size" field of struct mddev_s to "dev_sectors"
and stores the number of 512-byte sectors instead of the number of
1K-blocks in it.

All users of that field, including raid levels 1,4-6,10, are adjusted
accordingly. This simplifies the code a bit because it allows to get
rid of a couple of divisions/multiplications by two.

In order to make checkpatch happy, some minor coding style issues
have also been addressed. In particular, size_store() now uses
strict_strtoull() instead of simple_strtoull().
Signed-off-by: NAndre Noll <maan@systemlinux.org>
Signed-off-by: NNeilBrown <neilb@suse.de>
      58c0fed4
    • N
      md: occasionally checkpoint drive recovery to reduce duplicate effort after a crash · 97e4f42d
      由 NeilBrown 提交于 
      Version 1.x metadata has the ability to record the status of a
partially completed drive recovery.
However we only update that record on a clean shutdown.
It would be nice to update it on unclean shutdowns too, particularly
when using a bitmap that removes much to the 'sync' effort after an
unclean shutdown.

One complication with checkpointing recovery is that we only know
where we are up to in terms of IO requests started, not which ones
have completed.  And we need to know what has completed to record
how much is recovered.  So occasionally pause the recovery until all
submitted requests are completed, then update the record of where
we are up to.

When we have a bitmap, we already do that pause occasionally to keep
the bitmap up-to-date.  So enhance that code to record the recovery
offset and schedule a superblock update.
And when there is no bitmap, just pause 16 times during the resync to
do a checkpoint.
'16' is a fairly arbitrary number.  But we don't really have any good
way to judge how often is acceptable, and it seems like a reasonable
number for now.
Signed-off-by: NNeilBrown <neilb@suse.de>
      97e4f42d
    • N
      md: move md_k.h from include/linux/raid/ to drivers/md/ · 43b2e5d8
      由 NeilBrown 提交于 
      It really is nicer to keep related code together..
Signed-off-by: NNeilBrown <neilb@suse.de>
      43b2e5d8
    • N
      md: move lots of #include lines out of .h files and into .c · bff61975
      由 NeilBrown 提交于 
      This makes the includes more explicit, and is preparation for moving
md_k.h to drivers/md/md.h

Remove include/raid/md.h as its only remaining use was to #include
other files.
Signed-off-by: NNeilBrown <neilb@suse.de>
      bff61975
    • C
      md: move headers out of include/linux/raid/ · ef740c37
      由 Christoph Hellwig 提交于 
      Move the headers with the local structures for the disciplines and
bitmap.h into drivers/md/ so that they are more easily grepable for
hacking and not far away.  md.h is left where it is for now as there
are some uses from the outside.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNeilBrown <neilb@suse.de>
      ef740c37
    • N
      md: write bitmap information to devices that are undergoing recovery. · 355a43e6
      由 NeilBrown 提交于 
      When we add some spares to an array and start recovery, and we have
a bitmap which is stored 'internally' on all devices, we call
bitmap_write_all to make sure the bitmap is correct on the new
device(s).
However that doesn't work as write_sb_page only writes to
'In_sync' devices, and devices undergoing recovery are not
'In_sync' until recovery finishes.

So extend write_sb_page (actually next_active_rdev) to include devices
that are under recovery.
Signed-off-by: NNeilBrown <neilb@suse.de>
      355a43e6
    • N
      md: never clear bit from the write-intent bitmap when the array is degraded. · d0a4bb49
      由 NeilBrown 提交于 
      
It is safe to clear a bit from the write-intent bitmap for a raid1
if we know the data has been written to all devices, which is
what the current test does.

But it is not always safe to update the 'events_cleared' counter in
that case.  This is because one request could complete successfully
after some other request has partially failed.

So simply disable the clearing and updating of events_cleared whenever
the array is degraded.  This might end up not clearing some bits that
could safely be cleared, but it is safest approach.

Note that the bug fixed here did not risk corrupting data by letting
the array get out-of-sync.  Rather it meant that when a device is
removed and re-added to the array, it might incorrectly require a full
recovery rather than just recovering based on the bitmap.
Signed-off-by: NNeilBrown <neilb@suse.de>
      d0a4bb49
    • N
      md: Allow write-intent bitmaps to have chunksize < PAGE_SIZE · 1187cf0a
      由 NeilBrown 提交于 
      md currently insists that the chunk size used for write-intent
bitmaps (the amount of data that corresponds to one chunk)
be at least one page.

The reason for this restriction is lost in the mists of time,
but a review of the code (and a vague memory) suggests that the only
problem would be related to resync.  Resync tries very hard to
work in multiples of a page, but also needs to sync with units
of a bitmap_chunk too.

This connection comes out in the bitmap_start_sync call.

So change bitmap_start_sync to always work in multiples of a page.
If the bitmap chunk size is less that one page, we flag multiple
chunks as 'syncing' and generally make them all appear to the
resync routines like one chunk.

All other code either already works with data ranges that could
span multiple chunks, or explicitly only cares about a single chunk.
Signed-off-by: NNeil Brown <neilb@suse.de>
      1187cf0a
  17. 09 1月, 2009 2 次提交
    • C
      md: use list_for_each_entry macro directly · 159ec1fc
      由 Cheng Renquan 提交于 
      The rdev_for_each macro defined in <linux/raid/md_k.h> is identical to
list_for_each_entry_safe, from <linux/list.h>, it should be defined to
use list_for_each_entry_safe, instead of reinventing the wheel.

But some calls to each_entry_safe don't really need a safe version,
just a direct list_for_each_entry is enough, this could save a temp
variable (tmp) in every function that used rdev_for_each.

In this patch, most rdev_for_each loops are replaced by list_for_each_entry,
totally save many tmp vars; and only in the other situations that will call
list_del to delete an entry, the safe version is used.
Signed-off-by: NCheng Renquan <crquan@gmail.com>
Signed-off-by: NNeilBrown <neilb@suse.de>
      159ec1fc
    • N
      md: fix bitmap-on-external-file bug. · 53845270
      由 NeilBrown 提交于 
      commit a2ed9615
fixed a bug with 'internal' bitmaps, but in the process broke
'in a file' bitmaps.  So they are broken in 2.6.28

This fixes it, and needs to go in 2.6.28-stable.
Signed-off-by: NNeilBrown <neilb@suse.de>
Cc: stable@kernel.org
      53845270
  19. 19 12月, 2008 1 次提交
    • N
      md: Don't read past end of bitmap when reading bitmap. · a2ed9615
      由 NeilBrown 提交于 
      When we read the write-intent-bitmap off the device, we currently
read a whole number of pages.
When PAGE_SIZE is 4K, this works due to the alignment we enforce
on the superblock and bitmap.
When PAGE_SIZE is 64K, this case read past the end-of-device
which causes an error.

When we write the superblock, we ensure to clip the last page
to just be the required size.  Copy that code into the read path
to just read the required number of sectors.
Signed-off-by: NNeil Brown <neilb@suse.de>
Cc: stable@kernel.org
      a2ed9615
  21. 01 9月, 2008 1 次提交
    • N
      Fix problem with waiting while holding rcu read lock in md/bitmap.c · b2d2c4ce
      由 NeilBrown 提交于 
      A recent patch to protect the rdev list with rcu locking leaves us
with a problem because we can sleep on memalloc while holding the
rcu lock.

The rcu lock is only needed while walking the linked list as
uninteresting devices (failed or spares) can be removed at any time.

So only take the rcu lock while actually walking the linked list.
Take a refcount on the rdev during the time when we drop the lock
and do the memalloc to start IO.
When we return to the locked code, all the interesting devices
on the list will not have moved, so we can simply use
list_for_each_continue_rcu to pick up where we left off.
Signed-off-by: NNeilBrown <neilb@suse.de>
      b2d2c4ce
  23. 02 8月, 2008 1 次提交
  25. 21 7月, 2008 1 次提交
    • N
      md: Protect access to mddev->disks list using RCU · 4b80991c
      由 NeilBrown 提交于 
      All modifications and most access to the mddev->disks list are made
under the reconfig_mutex lock.  However there are three places where
the list is walked without any locking.  If a reconfig happens at this
time, havoc (and oops) can ensue.

So use RCU to protect these accesses:
  - wrap them in rcu_read_{,un}lock()
  - use list_for_each_entry_rcu
  - add to the list with list_add_rcu
  - delete from the list with list_del_rcu
  - delay the 'free' with call_rcu rather than schedule_work

Note that export_rdev did a list_del_init on this list.  In almost all
cases the entry was not in the list anymore so it was a no-op and so
safe.  It is no longer safe as after list_del_rcu we may not touch
the list_head.
An audit shows that export_rdev is called:
  - after unbind_rdev_from_array, in which case the delete has
     already been done,
  - after bind_rdev_to_array fails, in which case the delete isn't needed.
  - before the device has been put on a list at all (e.g. in
      add_new_disk where reading the superblock fails).
  - and in autorun devices after a failure when the device is on a
      different list.

So remove the list_del_init call from export_rdev, and add it back
immediately before the called to export_rdev for that last case.

Note also that ->same_set is sometimes used for lists other than
mddev->list (e.g. candidates).  In these cases rcu is not needed.
Signed-off-by: NNeilBrown <neilb@suse.de>
      4b80991c
  27. 11 7月, 2008 1 次提交
  29. 28 6月, 2008 1 次提交
    • N
      Improve setting of "events_cleared" for write-intent bitmaps. · a0da84f3
      由 Neil Brown 提交于 
      When an array is degraded, bits in the write-intent bitmap are not
cleared, so that if the missing device is re-added, it can be synced
by only updated those parts of the device that have changed since
it was removed.

The enable this a 'events_cleared' value is stored. It is the event
counter for the array the last time that any bits were cleared.

Sometimes - if a device disappears from an array while it is 'clean' -
the events_cleared value gets updated incorrectly (there are subtle
ordering issues between updateing events in the main metadata and the
bitmap metadata) resulting in the missing device appearing to require
a full resync when it is re-added.

With this patch, we update events_cleared precisely when we are about
to clear a bit in the bitmap.  We record events_cleared when we clear
the bit internally, and copy that to the superblock which is written
out before the bit on storage.  This makes it more "obviously correct".

We also need to update events_cleared when the event_count is going
backwards (as happens on a dirty->clean transition of a non-degraded
array).

Thanks to Mike Snitzer for identifying this problem and testing early
"fixes".

Cc:  "Mike Snitzer" <snitzer@gmail.com>
Signed-off-by: NNeil Brown <neilb@suse.de>
      a0da84f3
  31. 25 5月, 2008 1 次提交
  33. 11 3月, 2008 1 次提交
  35. 05 3月, 2008 1 次提交
  37. 15 2月, 2008 1 次提交
  39. 07 2月, 2008 2 次提交
  41. 09 11月, 2007 1 次提交
  43. 23 10月, 2007 1 次提交
  45. 18 7月, 2007 2 次提交
  47. 24 5月, 2007 1 次提交
  49. 09 5月, 2007 1 次提交
  51. 13 4月, 2007 1 次提交
  53. 12 2月, 2007 1 次提交
  55. 10 2月, 2007 1 次提交
    • N
      [PATCH] md: avoid possible BUG_ON in md bitmap handling · da6e1a32
      由 Neil Brown 提交于 
      md/bitmap tracks how many active write requests are pending on blocks
associated with each bit in the bitmap, so that it knows when it can clear
the bit (when count hits zero).

The counter has 14 bits of space, so if there are ever more than 16383, we
cannot cope.

Currently the code just calles BUG_ON as "all" drivers have request queue
limits much smaller than this.

However is seems that some don't.  Apparently some multipath configurations
can allow more than 16383 concurrent write requests.

So, in this unlikely situation, instead of calling BUG_ON we now wait
for the count to drop down a bit.  This requires a new wait_queue_head,
some waiting code, and a wakeup call.

Tested by limiting the counter to 20 instead of 16383 (writes go a lot slower
in that case...).
Signed-off-by: NNeil Brown <neilb@suse.de>
Cc: <stable@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      da6e1a32
  57. 27 1月, 2007 1 次提交