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| author | Lars Ellenberg <lars.ellenberg@linbit.com> | 2011-11-24 13:36:25 +0400 |
|---|---|---|
| committer | Philipp Reisner <philipp.reisner@linbit.com> | 2012-11-08 19:58:21 +0400 |
| commit | 2312f0b3c5ab794fbac9e9bebe90c784c9d449c5 (patch) | |
| tree | 0b4b74af502169d61e026855593b828fa202665a /drivers/block/drbd/drbd_req.h | |
| parent | f9916d61a40e7ad43c2a20444894f85c45512f91 (diff) | |
| download | linux-2312f0b3c5ab794fbac9e9bebe90c784c9d449c5.tar.xz | |
drbd: fix potential deadlock during "restart" of conflicting writes
w_restart_write(), run from worker context, calls __drbd_make_request()
and further drbd_al_begin_io(, delegate=true), which then
potentially deadlocks. The previous patch moved a BUG_ON to expose
such call paths, which would now be triggered.
Also, if we call __drbd_make_request() from resource worker context,
like w_restart_write() did, and that should block for whatever reason
(!drbd_state_is_stable(), resource suspended, ...),
we potentially deadlock the whole resource, as the worker
is needed for state changes and other things.
Create a dedicated retry workqueue for this instead.
Also make sure that inc_ap_bio()/dec_ap_bio() are properly paired,
even if do_retry() needs to retry itself,
in case __drbd_make_request() returns != 0.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Diffstat (limited to 'drivers/block/drbd/drbd_req.h')
| -rw-r--r-- | drivers/block/drbd/drbd_req.h | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/block/drbd/drbd_req.h b/drivers/block/drbd/drbd_req.h index 68f54050b7ca..492f81d3765a 100644 --- a/drivers/block/drbd/drbd_req.h +++ b/drivers/block/drbd/drbd_req.h @@ -268,6 +268,9 @@ extern void request_timer_fn(unsigned long data); extern void tl_restart(struct drbd_tconn *tconn, enum drbd_req_event what); extern void _tl_restart(struct drbd_tconn *tconn, enum drbd_req_event what); +/* this is in drbd_main.c */ +extern void drbd_restart_write(struct drbd_request *req); + /* use this if you don't want to deal with calling complete_master_bio() * outside the spinlock, e.g. when walking some list on cleanup. */ static inline int _req_mod(struct drbd_request *req, enum drbd_req_event what) |