linux-stable/include/linux/raid
Neil Brown da6e1a32fb [PATCH] md: avoid possible BUG_ON in md bitmap handling
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: Neil Brown <neilb@suse.de>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-09 09:25:47 -08:00
..
bitmap.h [PATCH] md: avoid possible BUG_ON in md bitmap handling 2007-02-09 09:25:47 -08:00
Kbuild
linear.h
md.h [PATCH] md: fix potential memalloc deadlock in md 2007-01-26 13:51:00 -08:00
md_k.h [PATCH] md: remove MAX_MD_DEVS which is an arbitrary limit 2006-10-03 08:04:18 -07:00
md_p.h [PATCH] md: endian annotation for v1 superblock access 2006-10-21 13:35:05 -07:00
md_u.h
multipath.h
raid0.h
raid1.h [PATCH] md: Remove working_disks from raid1 state data 2006-10-03 08:04:17 -07:00
raid5.h [PATCH] md: allow reads that have bypassed the cache to be retried on failure 2006-12-10 09:57:20 -08:00
raid10.h [PATCH] md: remove 'working_disks' from raid10 state 2006-10-03 08:04:17 -07:00
xor.h