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drbd: struct drbd_request: Introduce a new collision flag

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This flag is set when a processes puts itself to sleep to wait for a
conflicting request to complete.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
This commit is contained in:
Andreas Gruenbacher 2011-01-27 14:12:23 +01:00 committed by Philipp Reisner
parent 9e204cddaf
commit a500c2efbb
3 changed files with 15 additions and 41 deletions
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7
drivers/block/drbd/drbd_receiver.c
View File

@ -1815,6 +1815,7 @@ static int receive_Data(struct drbd_conf *mdev, enum drbd_packet cmd,
first = 1;
for (;;) {
struct drbd_interval *i;
struct drbd_request *req2;
int have_unacked = 0;
int have_conflict = 0;
prepare_to_wait(&mdev->misc_wait, &wait,
@ -1822,8 +1823,7 @@ static int receive_Data(struct drbd_conf *mdev, enum drbd_packet cmd,
i = drbd_find_overlap(&mdev->write_requests, sector, size);
if (i) {
struct drbd_request *req2 =
container_of(i, struct drbd_request, i);
req2 = container_of(i, struct drbd_request, i);
/* only ALERT on first iteration,
* we may be woken up early... */
@ -1869,6 +1869,9 @@ static int receive_Data(struct drbd_conf *mdev, enum drbd_packet cmd,
goto out_interrupted;
}
/* Indicate to wake up mdev->misc_wait upon completion. */
req2->rq_state |= RQ_COLLISION;
spin_unlock_irq(&mdev->tconn->req_lock);
if (first) {
first = 0;

42
drivers/block/drbd/drbd_req.c
View File

@ -176,45 +176,9 @@ static void _about_to_complete_local_write(struct drbd_conf *mdev,
req->epoch == mdev->tconn->newest_tle->br_number)
queue_barrier(mdev);
/* we need to do the conflict detection stuff,
* if the epoch_entries tree is non-empty and
* this request has completed on the network */
if ((s & RQ_NET_DONE) && !RB_EMPTY_ROOT(&mdev->epoch_entries)) {
const sector_t sector = req->i.sector;
const int size = req->i.size;
struct drbd_interval *i;
/* ASSERT:
* there must be no conflicting requests, since
* they must have been failed on the spot */
i = drbd_find_overlap(&mdev->write_requests, sector, size);
if (i) {
struct drbd_request *req2 =
container_of(i, struct drbd_request, i);
dev_alert(DEV, "LOGIC BUG: completed: %p %llus +%u; "
"other: %p %llus +%u\n",
req, (unsigned long long)sector, size,
i, (unsigned long long)req2->i.sector, req2->i.size);
}
/* maybe "wake" those conflicting epoch entries
* that wait for this request to finish.
*
* currently, there can be only _one_ such ee
* (well, or some more, which would be pending
* P_DISCARD_ACK not yet sent by the asender...),
* since we block the receiver thread upon the
* first conflict detection, which will wait on
* misc_wait. maybe we want to assert that?
*
* anyways, if we found one,
* we just have to do a wake_up. */
i = drbd_find_overlap(&mdev->epoch_entries, sector, size);
if (i)
wake_up(&mdev->misc_wait);
}
/* Wake up any processes waiting for this request to complete. */
if ((s & RQ_NET_DONE) && (s & RQ_COLLISION))
wake_up(&mdev->misc_wait);
}
void complete_master_bio(struct drbd_conf *mdev,

7
drivers/block/drbd/drbd_req.h
View File

@ -194,6 +194,12 @@ enum drbd_req_state_bits {
/* Should call drbd_al_complete_io() for this request... */
__RQ_IN_ACT_LOG,
/*
* Set when a processes puts itself to sleep to wait for this request
* to complete.
*/
__RQ_COLLISION,
};
#define RQ_LOCAL_PENDING (1UL << __RQ_LOCAL_PENDING)
@ -214,6 +220,7 @@ enum drbd_req_state_bits {
#define RQ_WRITE (1UL << __RQ_WRITE)
#define RQ_IN_ACT_LOG (1UL << __RQ_IN_ACT_LOG)
#define RQ_COLLISION (1UL << __RQ_COLLISION)
/* For waking up the frozen transfer log mod_req() has to return if the request
should be counted in the epoch object*/