drbd: Fixed a deadlock, probably only affected UP machines

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After disconnect (most likely mdev->net_cnt == 0) and we are
still in an unstable state (!drbd_state_is_stable()). When we
get an IO request in drbd_get_max_buffers() (called from
__inc_ap_bio_cond(), called from inc_ap_bio()) we wake up
misc_wait. Misc_wait is also used in inc_ap_bio() to sleep
until the outcome of __inc_ap_bio_cond() changes. => Busy loop!

Solution: Have a dedicated wait queue for get_net_conf() and
put_net_conf().

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

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This commit is contained in:

Philipp Reisner 2010-06-23 11:20:05 +02:00

parent 65d922c33e

commit 84dfb9f564

3 changed files with 4 additions and 2 deletions

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3

drivers/block/drbd/drbd_int.h

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1

drivers/block/drbd/drbd_main.c

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2

drivers/block/drbd/drbd_receiver.c

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