diff options
| -rw-r--r-- | drivers/block/drbd/drbd_int.h | 7 | ||||
| -rw-r--r-- | drivers/block/drbd/drbd_main.c | 16 | ||||
| -rw-r--r-- | drivers/block/drbd/drbd_nl.c | 6 |
3 files changed, 29 insertions, 0 deletions
diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h index 79c69ebb0653..5136510ec8be 100644 --- a/drivers/block/drbd/drbd_int.h +++ b/drivers/block/drbd/drbd_int.h @@ -850,6 +850,13 @@ enum { AL_SUSPENDED, /* Activity logging is currently suspended. */ AHEAD_TO_SYNC_SOURCE, /* Ahead -> SyncSource queued */ STATE_SENT, /* Do not change state/UUIDs while this is set */ + + CALLBACK_PENDING, /* Whether we have a call_usermodehelper(, UMH_WAIT_PROC) + * pending, from drbd worker context. + * If set, bdi_write_congested() returns true, + * so shrink_page_list() would not recurse into, + * and potentially deadlock on, this drbd worker. + */ }; struct drbd_bitmap; /* opaque for drbd_conf */ diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c index 5bebe8d8ace3..41ccb580d5ac 100644 --- a/drivers/block/drbd/drbd_main.c +++ b/drivers/block/drbd/drbd_main.c @@ -3553,6 +3553,22 @@ static int drbd_congested(void *congested_data, int bdi_bits) goto out; } + if (test_bit(CALLBACK_PENDING, &mdev->flags)) { + r |= (1 << BDI_async_congested); + /* Without good local data, we would need to read from remote, + * and that would need the worker thread as well, which is + * currently blocked waiting for that usermode helper to + * finish. + */ + if (!get_ldev_if_state(mdev, D_UP_TO_DATE)) + r |= (1 << BDI_sync_congested); + else + put_ldev(mdev); + r &= bdi_bits; + reason = 'c'; + goto out; + } + if (get_ldev(mdev)) { q = bdev_get_queue(mdev->ldev->backing_bdev); r = bdi_congested(&q->backing_dev_info, bdi_bits); diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c index 40a1c4f07190..03fc853be2b9 100644 --- a/drivers/block/drbd/drbd_nl.c +++ b/drivers/block/drbd/drbd_nl.c @@ -147,6 +147,9 @@ int drbd_khelper(struct drbd_conf *mdev, char *cmd) char *argv[] = {usermode_helper, cmd, mb, NULL }; int ret; + if (current == mdev->worker.task) + set_bit(CALLBACK_PENDING, &mdev->flags); + snprintf(mb, 12, "minor-%d", mdev_to_minor(mdev)); if (get_net_conf(mdev)) { @@ -189,6 +192,9 @@ int drbd_khelper(struct drbd_conf *mdev, char *cmd) usermode_helper, cmd, mb, (ret >> 8) & 0xff, ret); + if (current == mdev->worker.task) + clear_bit(CALLBACK_PENDING, &mdev->flags); + if (ret < 0) /* Ignore any ERRNOs we got. */ ret = 0; |