linux-toradex.git/drivers/block/drbd/drbd_bitmap.c, branch v3.7

drbd: Write all pages of the bitmap after an online resize

2012-08-16T15:17:35+00:00

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 
Signed-off-by: Lars Ellenberg

drbd: differentiate between normal and forced detach

2012-07-24T12:06:18+00:00

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 
Signed-off-by: Lars Ellenberg

drbd: fix access of unallocated pages and kernel panic

2012-06-12T12:32:48+00:00

BUG: unable to handle kernel NULL pointer dereference at (null)
...
 [] ? _drbd_bm_set_bits+0x151/0x240 [drbd]
 [] ? 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 
Signed-off-by: Lars Ellenberg

drbd: introduce a bio_set to allocate housekeeping bios from

2012-05-09T13:17:07+00:00

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 
Signed-off-by: Lars Ellenberg

drbd: bm_page_async_io: properly initialize page->private

2012-05-09T13:17:04+00:00

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 
Signed-off-by: Lars Ellenberg 
Signed-off-by: Philipp Reisner

drbd: use the newly introduced page pool for bitmap IO

2012-05-09T13:17:03+00:00

Conflicts:

	drbd/drbd_bitmap.c

Signed-off-by: Philipp Reisner 
Signed-off-by: Lars Ellenberg

drbd: allow bitmap to change during writeout from resync_finished

2012-05-09T13:17:00+00:00

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 
Signed-off-by: Lars Ellenberg

drbd: Consider the disk-timeout also for meta-data IO operations

2012-05-09T13:16:30+00:00

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 
Signed-off-by: Lars Ellenberg

drbd: change some GFP_KERNEL to GFP_NOIO

2012-05-09T13:10:47+00:00

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 
Signed-off-by: Lars Ellenberg

drbd: Bitmap IO functions can now return prematurely if the disk breaks

2012-05-09T13:10:33+00:00

Signed-off-by: Philipp Reisner 
Signed-off-by: Lars Ellenberg