Commit Graph

67 Commits

Author SHA1 Message Date
Akinobu Mita f1d6a328bb drbd: use copy_highpage
Use copy_highpage() to copy from one page to another.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-09 14:22:26 +01:00
Philipp Reisner 986836503e Merge branch 'drbd-8.4_ed6' into for-3.8-drivers-drbd-8.4_ed6 2012-11-09 14:20:23 +01:00
Lars Ellenberg e34b677d09 drbd: wait for meta data IO completion even with failed disk, unless force-detached
The intention of force-detach is to be able to deal with a completely
unresponsive lower level IO stack, which does not even deliver error
completions anymore, but no completion at all.

In all other cases, we must still wait for the meta data IO completion.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-09 14:11:40 +01:00
Lars Ellenberg bc891c9ae3 drbd: fix potential deadlock during bitmap (re-)allocation
The former comment arguing that GFP_KERNEL was good enough was wrong: it
did not take resize into account at all, and assumed the only path
leading here was the normal attach on a still secondary device, so no
deadlock would be possible.

Both resize on a Primary, or attach on a diskless Primary,
could potentially deadlock.

drbd_bm_resize() is called while IO to the respective device is
suspended, so we must use GFP_NOIO to avoid potential deadlock.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-09 14:11:39 +01:00
Philipp Reisner fef45d297e drbd: Write all pages of the bitmap after an online resize
We need to write the whole bitmap after we moved the meta data
due to an online resize operation.

With the support for one peta byte devices bitmap IO was optimized
to only write out touched pages. This optimization must be turned
off when writing the bitmap after an online resize.

This issue was introduced with drbd-8.3.10.

The impact of this bug is that after an online resize, the next
resync could become larger than expected.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-09 14:05:51 +01:00
Lars Ellenberg 0c84966601 drbd: differentiate between normal and forced detach
Aborting local requests (not waiting for completion from the lower level
disk) is dangerous: if the master bio has been completed to upper
layers, data pages may be re-used for other things already.
If local IO is still pending and later completes,
this may cause crashes or corrupt unrelated data.

Only abort local IO if explicitly requested.
Intended use case is a lower level device that turned into a tarpit,
not completing io requests, not even doing error completion.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-08 16:58:39 +01:00
Lars Ellenberg 1b6f19740d drbd: fix access of unallocated pages and kernel panic
BUG: unable to handle kernel NULL pointer dereference at (null)
...
 [<d1e17561>] ? _drbd_bm_set_bits+0x151/0x240 [drbd]
 [<d1e236f8>] ? receive_bitmap+0x4f8/0xbc0 [drbd]

This fixes an off-by-one error in the receive_bitmap() path,
if run-length encoded bitmap transfer is enabled.

If the bitmap is an exact multiple of PAGE_SIZE, which means the visible
capacity of the drbd device is an exact multiple of 128 MiB (for 4k page
size), and bitmap compression (use-rle) is enabled (which became default
with 8.4), and the very last bit is dirty and reported in an rle
comressed bitmap packet, we ended up trying to kmap_atomic a page pointer
that does not exist (bitmap->bm_pages[last index + 1]).

bug introduced by:
    Date:   Fri Jul 24 15:33:24 2009 +0200
    set bits: optimize for complete last word, fix off-by-one-word corner case

made effective by:
    Date:   Thu Dec 16 00:32:38 2010 +0100
    drbd: get rid of unused debug code

    Long time ago, we had paranoia code in the bitmap that allocated one
    extra word, assigned a magic value, and checked on every occasion that
    the magic value was still unchanged.

    That debug code is unused, the extra long word complicates code a bit.
    Get rid of it.

No-one triggered this bug in the last few years, because a large subset
of our userbase is unaffected:
 * typically the last few blocks of a device are not modified
   frequently, and remain unset
 * use-rle was disabled by default in drbd < 8.4
 * those with slightly "odd" device sizes, or
 * drbd internal meta data (which will skew the device size slightly,
   thus makes it harder to have a bug relevant device size)

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-08 16:58:32 +01:00
Lars Ellenberg f66ee69746 drbd: bm_page_async_io: properly initialize page->private
If bm_page_async_io is advised to use a new page for I/O
(BM_AIO_COPY_PAGES is set), it will get it from a mempool.
Once the mempool has to dip into its reserves the page is
not reinitialized, i.e. page->private contains garbage, which
will lead to various problems once the I/O completes (dereferences
of NULL pointers, the submitting thread getting stuck in D-state,
 ...).

Signed-off-by: Arne Redlich <arne.redlich@googlemail.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-08 16:58:28 +01:00
Lars Ellenberg a220d29180 drbd: allow bitmap to change during writeout from resync_finished
Symptom: messages similar to
 "FIXME asender in bm_change_bits_to,
  bitmap locked for 'write from resync_finished' by worker"

If a resync or verify is finished (or aborted), a full bitmap writeout
is triggered.  If we have ongoing local IO, the bitmap may still change
during that writeout, pending and not yet processed acks may cause bits
to be cleared, while new writes may cause bits to be to be set.

To fix this, introduce the drbd_bm_write_copy_pages() variant.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-08 16:58:28 +01:00
Lars Ellenberg 9dab3842b5 drbd: fix memleak in error path in bm_rw and drbd_bm_write_range
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-08 16:58:20 +01:00
Philipp Reisner 32db80f6f6 drbd: Consider the disk-timeout also for meta-data IO operations
If the backing device is already frozen during attach, we failed
to recognize that. The current disk-timeout code works on top
of the drbd_request objects. During attach we do not allow IO
and therefore never generate a drbd_request object but block
before that in drbd_make_request().

This patch adds the timeout to all drbd_md_sync_page_io().

Before this patch we used to go from D_ATTACHING directly
to D_DISKLESS if IO failed during attach. We can no longer
do this since we have to stay in D_FAILED until all IO
ops issued to the backing device returned.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-08 16:58:15 +01:00
Andreas Gruenbacher 1a3cde4406 drbd: drbd_bm_ALe_set_all(): Remove unused function
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-08 16:58:14 +01:00
Lars Ellenberg 22d81140ae drbd: fix bitmap writeout after aborted resync
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-08 16:58:04 +01:00
Andreas Gruenbacher a209b4aec3 drbd: Update some outdated comments to match the code
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-08 16:58:02 +01:00
Philipp Reisner cdfda633d2 drbd: detach from frozen backing device
* drbd-8.3:
  documentation: Documented detach's --force and disk's --disk-timeout
  drbd: Implemented the disk-timeout option
  drbd: Force flag for the detach operation
  drbd: Allow new IOs while the local disk in in FAILED state
  drbd: Bitmap IO functions can not return prematurely if the disk breaks
  drbd: Added a kref to bm_aio_ctx
  drbd: Hold a reference to ldev while doing meta-data IO
  drbd: Keep a reference to the bio until the completion handler finished
  drbd: Implemented wait_until_done_or_disk_failure()
  drbd: Replaced md_io_mutex by an atomic: md_io_in_use
  drbd: moved md_io into mdev
  drbd: Immediately allow completion of IOs, that wait for IO completions on a failed disk
  drbd: Keep a reference to barrier acked requests

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-08 16:57:50 +01:00
Lars Ellenberg 44edfb0d78 drbd: wait for meta data IO completion even with failed disk, unless force-detached
The intention of force-detach is to be able to deal with a completely
unresponsive lower level IO stack, which does not even deliver error
completions anymore, but no completion at all.

In all other cases, we must still wait for the meta data IO completion.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2012-10-30 08:39:18 +01:00
Lars Ellenberg 0b143d4382 drbd: fix potential deadlock during bitmap (re-)allocation
The former comment arguing that GFP_KERNEL was good enough was wrong: it
did not take resize into account at all, and assumed the only path
leading here was the normal attach on a still secondary device, so no
deadlock would be possible.

Both resize on a Primary, or attach on a diskless Primary,
could potentially deadlock.

drbd_bm_resize() is called while IO to the respective device is
suspended, so we must use GFP_NOIO to avoid potential deadlock.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2012-10-30 08:39:18 +01:00
Philipp Reisner d1aa4d04da drbd: Write all pages of the bitmap after an online resize
We need to write the whole bitmap after we moved the meta data
due to an online resize operation.

With the support for one peta byte devices bitmap IO was optimized
to only write out touched pages. This optimization must be turned
off when writing the bitmap after an online resize.

This issue was introduced with drbd-8.3.10.

The impact of this bug is that after an online resize, the next
resync could become larger than expected.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-08-16 17:17:35 +02:00
Lars Ellenberg 383606e0de drbd: differentiate between normal and forced detach
Aborting local requests (not waiting for completion from the lower level
disk) is dangerous: if the master bio has been completed to upper
layers, data pages may be re-used for other things already.
If local IO is still pending and later completes,
this may cause crashes or corrupt unrelated data.

Only abort local IO if explicitly requested.
Intended use case is a lower level device that turned into a tarpit,
not completing io requests, not even doing error completion.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-07-24 14:06:18 +02:00
Lars Ellenberg 4eccc57979 drbd: fix access of unallocated pages and kernel panic
BUG: unable to handle kernel NULL pointer dereference at (null)
...
 [<d1e17561>] ? _drbd_bm_set_bits+0x151/0x240 [drbd]
 [<d1e236f8>] ? receive_bitmap+0x4f8/0xbc0 [drbd]

This fixes an off-by-one error in the receive_bitmap() path,
if run-length encoded bitmap transfer is enabled.

If the bitmap is an exact multiple of PAGE_SIZE, which means the visible
capacity of the drbd device is an exact multiple of 128 MiB (for 4k page
size), and bitmap compression (use-rle) is enabled (which became default
with 8.4), and the very last bit is dirty and reported in an rle
comressed bitmap packet, we ended up trying to kmap_atomic a page pointer
that does not exist (bitmap->bm_pages[last index + 1]).

bug introduced by:
    Date:   Fri Jul 24 15:33:24 2009 +0200
    set bits: optimize for complete last word, fix off-by-one-word corner case

made effective by:
    Date:   Thu Dec 16 00:32:38 2010 +0100
    drbd: get rid of unused debug code

    Long time ago, we had paranoia code in the bitmap that allocated one
    extra word, assigned a magic value, and checked on every occasion that
    the magic value was still unchanged.

    That debug code is unused, the extra long word complicates code a bit.
    Get rid of it.

No-one triggered this bug in the last few years, because a large subset
of our userbase is unaffected:
 * typically the last few blocks of a device are not modified
   frequently, and remain unset
 * use-rle was disabled by default in drbd < 8.4
 * those with slightly "odd" device sizes, or
 * drbd internal meta data (which will skew the device size slightly,
   thus makes it harder to have a bug relevant device size)

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-06-12 14:32:48 +02:00
Lars Ellenberg 9476f39d66 drbd: introduce a bio_set to allocate housekeeping bios from
Don't rely on availability of bios from the global fs_bio_set,
we should use our own bio_set for meta data IO.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-05-09 15:17:07 +02:00
Arne Redlich 0c7db27920 drbd: bm_page_async_io: properly initialize page->private
If bm_page_async_io is advised to use a new page for I/O
(BM_AIO_COPY_PAGES is set), it will get it from a mempool.
Once the mempool has to dip into its reserves the page is
not reinitialized, i.e. page->private contains garbage, which
will lead to various problems once the I/O completes (dereferences
of NULL pointers, the submitting thread getting stuck in D-state,
 ...).

Signed-off-by: Arne Redlich <arne.redlich@googlemail.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
2012-05-09 15:17:04 +02:00
Lars Ellenberg 4d95a10f97 drbd: use the newly introduced page pool for bitmap IO
Conflicts:

	drbd/drbd_bitmap.c

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-05-09 15:17:03 +02:00
Lars Ellenberg 0e8488ade2 drbd: allow bitmap to change during writeout from resync_finished
Symptom: messages similar to
 "FIXME asender in bm_change_bits_to,
  bitmap locked for 'write from resync_finished' by worker"

If a resync or verify is finished (or aborted), a full bitmap writeout
is triggered.  If we have ongoing local IO, the bitmap may still change
during that writeout, pending and not yet processed acks may cause bits
to be cleared, while new writes may cause bits to be to be set.

To fix this, introduce the drbd_bm_write_copy_pages() variant.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-05-09 15:17:00 +02:00
Philipp Reisner 7caacb69ac drbd: Consider the disk-timeout also for meta-data IO operations
If the backing device is already frozen during attach, we failed
to recognize that. The current disk-timeout code works on top
of the drbd_request objects. During attach we do not allow IO
and therefore never generate a drbd_request object but block
before that in drbd_make_request().

This patch adds the timeout to all drbd_md_sync_page_io().

Before this patch we used to go from D_ATTACHING directly
to D_DISKLESS if IO failed during attach. We can no longer
do this since we have to stay in D_FAILED until all IO
ops issued to the backing device returned.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-05-09 15:16:30 +02:00
Lars Ellenberg 22f46ce2ef drbd: change some GFP_KERNEL to GFP_NOIO
Bitmap IO may happend in the context of an application write,
in the generic block IO path.  We need to use GFP_NOIO.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-05-09 15:10:47 +02:00
Philipp Reisner 9e58c4dad7 drbd: Bitmap IO functions can now return prematurely if the disk breaks
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-05-09 15:10:33 +02:00
Philipp Reisner d1f3779bbe drbd: Added a kref to bm_aio_ctx
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-05-09 10:37:19 +02:00
Cong Wang 589973a704 drbd: remove the second argument of k[un]map_atomic()
Signed-off-by: Cong Wang <amwang@redhat.com>
2012-03-20 21:48:29 +08:00
Cong Wang cfd8005c99 block: remove the second argument of k[un]map_atomic()
Signed-off-by: Cong Wang <amwang@redhat.com>
2012-03-20 21:48:16 +08:00
Lars Ellenberg da4a75d2ef drbd: introduce a bio_set to allocate housekeeping bios from
Don't rely on availability of bios from the global fs_bio_set,
we should use our own bio_set for meta data IO.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2011-10-14 16:48:06 +02:00
Lars Ellenberg 9db4e77f8c drbd: use the newly introduced page pool for bitmap IO
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2011-10-14 16:48:05 +02:00
Lars Ellenberg c9d963a46d drbd: silence some log messages on bitmap IO
Summary log messages meant for global bitmap IO
should not be printed for bitmap IO caused by
activity log transactions.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2011-10-14 16:47:47 +02:00
Lars Ellenberg 45dfffebd0 drbd: allow to select specific bitmap pages for writeout
We are about to allow several changes to the active set in one activity
log transaction. We have to write out the corresponding bitmap pages as
well, if changed.

Introduce drbd_bm_mark_for_writeout(), then re-use the existing bitmap
writeout path to submit all marked pages in one go.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2011-10-14 16:47:44 +02:00
Lars Ellenberg 4738fa1690 drbd: use clear_bit_unlock() where appropriate
Some open-coded clear_bit(); smp_mb__after_clear_bit();
should in fact have been smp_mb__before_clear_bit(); clear_bit();

Instead, use clear_bit_unlock() to annotate the intention,
and have it do the right thing.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2011-10-14 16:47:42 +02:00
Philipp Reisner 392c880192 drbd: drbd_thread has now a pointer to a tconn instead of to a mdev
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2011-09-28 10:33:13 +02:00
Philipp Reisner bed879ae90 drbd: Moved the thread name into the data structure
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2011-09-28 10:26:44 +02:00
Joe Perches 57f3224c3f drbd: Convert vmalloc/memset to vzalloc
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2011-09-15 13:55:02 +02:00
Philipp Reisner e6b3ea83bc drbd: moved receiver, worker and asender from mdev to tconn
Patch mostly:
sed -i -e 's/mdev->receiver/mdev->tconn->receiver/g' \
       -e 's/mdev->worker/mdev->tconn->worker/g' \
       -e 's/mdev->asender/mdev->tconn->asender/g' \
       *.[ch]

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2011-08-29 11:27:06 +02:00
Andreas Gruenbacher 841ce241fa drbd: Replace the ERR_IF macro with an assert-like macro
Remove the file name and line number from the syslog messages generated:
we have no duplicate function names, and no function contains the same
assertion more than once.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2011-08-29 11:26:57 +02:00
Lars Ellenberg 5a8b424276 drbd: account bitmap IO during resync as resync-(related-)-io
If we have a good resync rate, we will frequently update the on-disk
bitmap, which, if not accounted for as resync io, may let an otherwise
idle device appear to be "busy", and cause us to throttle resync.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2011-06-30 09:23:43 +02:00
Lars Ellenberg 8ccee20e3e drbd: don't cond_resched_lock with IRQs disabled
The last commit, drbd: add missing spinlock to bitmap receive,
introduced a cond_resched_lock(), where the lock in question is taken
with irqs disabled.

As we must not schedule with IRQs disabled,
and cond_resched_lock_irq() does not exist, yet,
we re-aquire the spin_lock_irq() for each bitmap page processed in turn.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2011-06-30 09:23:42 +02:00
Lars Ellenberg 829c608786 drbd: add missing spinlock to bitmap receive
During bitmap exchange, when using the RLE bitmap compression scheme,
we have a code path that can set the whole bitmap at once.

To avoid holding spin_lock_irq() for too long, we used to lock out other
bitmap modifications during bitmap exchange by other means, and then,
knowing we have exclusive access to the bitmap, modify it without
the spinlock, and with IRQs enabled.

Since we now allow local IO to continue, potentially setting additional
bits during the bitmap receive phase, this is no longer true, and we get
uncoordinated updates of bitmap members, causing bm_set to no longer
accurately reflect the total number of set bits.

To actually see this, you'd need to have a large bitmap, use RLE bitmap
compression, and have busy IO during sync handshake and bitmap exchange.

Fix this by taking the spin_lock_irq() in this code path as well, but
calling cond_resched_lock() after each page worth of bits processed.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2011-06-30 09:23:41 +02:00
Bart Van Assche 24c4830c8e drbd: Fix spelling
Found these with the help of ispell -l.

Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
2011-05-24 10:21:29 +02:00
Linus Torvalds 7e599e6e62 drbd: fix up merge error
In commit 95a0f10cdd ("drbd: store in-core bitmap little endian,
regardless of architecture") drbd had made the sane choice to use
little-endian bitmap functions everywhere.  However, it used the
horrible old functions names from <asm-generic/bitops/le.h>, that were
never really meant to be exported.

In the meantime, things got cleaned up, and in commit c4945b9ed4
("asm-generic: rename generic little-endian bitops functions") we
renamed the LE bitops to something sane, exactly so that they could be
used in random code without people gouging their eyes out when seeing
the crazy jumble of letters that were the old internal names.

As a result the drbd thing merged cleanly (commit 8d49a77568d1: "Merge
branch 'for-2.6.39/drivers' of git://git.kernel.dk/linux-2.6-block"),
since there was no data conflict - but the end result obviously doesn't
actually compile.

Reported-and-tested-by: Ingo Molnar <mingo@elte.hu>
Cc: Jens Axboe <jaxboe@fusionio.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-28 07:42:58 -07:00
Stephen Rothwell f0ff1357ce drbd: need include for bitops functions declarations
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-03-17 15:02:51 +01:00
Lars Ellenberg 20ceb2b22e drbd: describe bitmap locking for bulk operation in finer detail
Now that we do no longer in-place endian-swap the bitmap, we allow
selected bitmap operations (testing bits, sometimes even settting bits)
during some bulk operations.

This caused us to hit a lot of FIXME asserts similar to
	FIXME asender in drbd_bm_count_bits,
	bitmap locked for 'write from resync_finished' by worker
Which now is nonsense: looking at the bitmap is perfectly legal
as long as it is not being resized.

This cosmetic patch defines some flags to describe expectations in finer
detail, so the asserts in e.g. bm_change_bits_to() can be skipped if
appropriate.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2011-03-10 11:48:02 +01:00
Lars Ellenberg 725a97e43e drbd: fix potential access of on-stack wait_queue_head_t after return
I run into something declaring itself as "spinlock deadlock",
 BUG: spinlock lockup on CPU#1, kjournald/27816, ffff88000ad6bca0
 Pid: 27816, comm: kjournald Tainted: G        W 2.6.34.6 #2
 Call Trace:
  <IRQ>  [<ffffffff811ba0aa>] do_raw_spin_lock+0x11e/0x14d
  [<ffffffff81340fde>] _raw_spin_lock_irqsave+0x6a/0x81
  [<ffffffff8103b694>] ? __wake_up+0x22/0x50
  [<ffffffff8103b694>] __wake_up+0x22/0x50
  [<ffffffffa07ff661>] bm_async_io_complete+0x258/0x299 [drbd]
but the call traces do not fit at all,
all other cpus are cpu_idle.

I think it may be this race:

drbd_bm_write_page
 wait_queue_head_t io_wait;
 atomic_t in_flight;
 bm_async_io
  submit_bio
					bm_async_io_complete
					  if (atomic_dec_and_test(in_flight))
 wait_event(io_wait,
	atomic_read(in_flight) == 0)
 return
					    wake_up(io_wait)

The wake_up now accesses the wait_queue_head_t spinlock, which is no
longer valid, since the stack frame of drbd_bm_write_page has been
clobbered now.

Fix this by using struct completion, which does both the condition test
as well as the wake_up inside its spinlock, so this race cannot happen.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2011-03-10 11:45:08 +01:00
Lars Ellenberg 7648cdfe52 drbd: be less noisy with some log messages
We expect changes to a bitmap page in drbd_bm_write_page,
that's why we submit a copy page.

If a page changes during global writeout, that would be unexpected,
and reason to warn, though.

Also, often page writeout can be skipped (on activity log transactions
during normal operation, for example), no need to log that everytime.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2011-03-10 11:43:37 +01:00
Lars Ellenberg 84e7c0f7d1 drbd: Removed a reference to debug macros removed long time ago
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2011-03-10 11:43:27 +01:00