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drbd: fix resend/resubmit of frozen IO 

DRBD can freeze IO, due to fencing policy (fencing resource-and-stonith),
or because we lost access to data (on-no-data-accessible suspend-io).

Resuming from there (re-connect, or re-attach, or explicit admin
intervention) should "just work".

Unfortunately, if the re-attach/re-connect did not happen within
the timeout, since the commit
  drbd: Implemented real timeout checking for request processing time
if so configured, the request_timer_fn() would timeout and
detach/disconnect virtually immediately.

This change tracks the most recent attach and connect, and does not
timeout within <configured timeout interval> after attach/connect.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
This commit is contained in:
Lars Ellenberg 2012-04-25 11:46:14 +02:00 committed by Philipp Reisner
parent 5de738272e
commit ba280c092e
3 changed files with 48 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
drivers/block/drbd/drbd_int.h
View File

@ -1049,6 +1049,8 @@ struct drbd_conf {
struct crypto_hash *csums_tfm;
struct crypto_hash *verify_tfm;
unsigned long last_reattach_jif;
unsigned long last_reconnect_jif;
struct drbd_thread receiver;
struct drbd_thread worker;
struct drbd_thread asender;

9
drivers/block/drbd/drbd_main.c
View File

@ -1326,6 +1326,15 @@ __drbd_set_state(struct drbd_conf *mdev, union drbd_state ns,
if (os.conn < C_CONNECTED && ns.conn >= C_CONNECTED)
drbd_resume_al(mdev);
/* remember last connect and attach times so request_timer_fn() won't
* kill newly established sessions while we are still trying to thaw
* previously frozen IO */
if (os.conn != C_WF_REPORT_PARAMS && ns.conn == C_WF_REPORT_PARAMS)
mdev->last_reconnect_jif = jiffies;
if ((os.disk == D_ATTACHING || os.disk == D_NEGOTIATING) &&
ns.disk > D_NEGOTIATING)
mdev->last_reattach_jif = jiffies;
ascw = kmalloc(sizeof(*ascw), GFP_ATOMIC);
if (ascw) {
ascw->os = os;

52
drivers/block/drbd/drbd_req.c
View File

@ -1200,43 +1200,65 @@ void request_timer_fn(unsigned long data)
struct drbd_request *req; /* oldest request */
struct list_head *le;
unsigned long ent = 0, dt = 0, et, nt; /* effective timeout = ko_count * timeout */
unsigned long now;
if (get_net_conf(mdev)) {
ent = mdev->net_conf->timeout*HZ/10 * mdev->net_conf->ko_count;
if (mdev->state.conn >= C_WF_REPORT_PARAMS)
ent = mdev->net_conf->timeout*HZ/10
* mdev->net_conf->ko_count;
put_net_conf(mdev);
}
if (get_ldev(mdev)) {
if (get_ldev(mdev)) { /* implicit state.disk >= D_INCONSISTENT */
dt = mdev->ldev->dc.disk_timeout * HZ / 10;
put_ldev(mdev);
}
et = min_not_zero(dt, ent);
if (!et || (mdev->state.conn < C_WF_REPORT_PARAMS && mdev->state.disk <= D_FAILED))
if (!et)
return; /* Recurring timer stopped */
now = jiffies;
spin_lock_irq(&mdev->req_lock);
le = &mdev->oldest_tle->requests;
if (list_empty(le)) {
spin_unlock_irq(&mdev->req_lock);
mod_timer(&mdev->request_timer, jiffies + et);
mod_timer(&mdev->request_timer, now + et);
return;
}
le = le->prev;
req = list_entry(le, struct drbd_request, tl_requests);
if (ent && req->rq_state & RQ_NET_PENDING) {
if (time_is_before_eq_jiffies(req->start_time + ent)) {
dev_warn(DEV, "Remote failed to finish a request within ko-count * timeout\n");
_drbd_set_state(_NS(mdev, conn, C_TIMEOUT), CS_VERBOSE | CS_HARD, NULL);
}
/* The request is considered timed out, if
* - we have some effective timeout from the configuration,
* with above state restrictions applied,
* - the oldest request is waiting for a response from the network
* resp. the local disk,
* - the oldest request is in fact older than the effective timeout,
* - the connection was established (resp. disk was attached)
* for longer than the timeout already.
* Note that for 32bit jiffies and very stable connections/disks,
* we may have a wrap around, which is catched by
* !time_in_range(now, last_..._jif, last_..._jif + timeout).
*
* Side effect: once per 32bit wrap-around interval, which means every
* ~198 days with 250 HZ, we have a window where the timeout would need
* to expire twice (worst case) to become effective. Good enough.
*/
if (ent && req->rq_state & RQ_NET_PENDING &&
time_after(now, req->start_time + ent) &&
!time_in_range(now, mdev->last_reconnect_jif, mdev->last_reconnect_jif + ent)) {
dev_warn(DEV, "Remote failed to finish a request within ko-count * timeout\n");
_drbd_set_state(_NS(mdev, conn, C_TIMEOUT), CS_VERBOSE | CS_HARD, NULL);
}
if (dt && req->rq_state & RQ_LOCAL_PENDING) {
if (time_is_before_eq_jiffies(req->start_time + dt)) {
dev_warn(DEV, "Local backing device failed to meet the disk-timeout\n");
__drbd_chk_io_error(mdev, 1);
}
if (dt && req->rq_state & RQ_LOCAL_PENDING &&
time_after(now, req->start_time + dt) &&
!time_in_range(now, mdev->last_reattach_jif, mdev->last_reattach_jif + dt)) {
dev_warn(DEV, "Local backing device failed to meet the disk-timeout\n");
__drbd_chk_io_error(mdev, 1);
}
nt = (time_is_before_eq_jiffies(req->start_time + et) ? jiffies : req->start_time) + et;
nt = (time_after(now, req->start_time + et) ? now : req->start_time) + et;
spin_unlock_irq(&mdev->req_lock);
mod_timer(&mdev->request_timer, nt);
}