mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-12-05 10:04:12 +08:00
a115413de1
In commit 9b7f76dc37919ea36caa9680a3f765e5b19b25fb, Author: Lars Ellenberg <lars.ellenberg@linbit.com> Date: Wed Aug 11 23:40:24 2010 +0200 drbd: new configuration parameter c-min-rate a bad chunk slipped through, which is now reverted as well, restoring the correct irqsave for the endio callback. This patch also add comments at both req_mod() and in the endio callback so it should not happen again. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
361 lines
11 KiB
C
361 lines
11 KiB
C
/*
|
|
drbd_req.h
|
|
|
|
This file is part of DRBD by Philipp Reisner and Lars Ellenberg.
|
|
|
|
Copyright (C) 2006-2008, LINBIT Information Technologies GmbH.
|
|
Copyright (C) 2006-2008, Lars Ellenberg <lars.ellenberg@linbit.com>.
|
|
Copyright (C) 2006-2008, Philipp Reisner <philipp.reisner@linbit.com>.
|
|
|
|
DRBD is free software; you can redistribute it and/or modify
|
|
it under the terms of the GNU General Public License as published by
|
|
the Free Software Foundation; either version 2, or (at your option)
|
|
any later version.
|
|
|
|
DRBD is distributed in the hope that it will be useful,
|
|
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
GNU General Public License for more details.
|
|
|
|
You should have received a copy of the GNU General Public License
|
|
along with drbd; see the file COPYING. If not, write to
|
|
the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
|
|
*/
|
|
|
|
#ifndef _DRBD_REQ_H
|
|
#define _DRBD_REQ_H
|
|
|
|
#include <linux/module.h>
|
|
|
|
#include <linux/slab.h>
|
|
#include <linux/drbd.h>
|
|
#include "drbd_int.h"
|
|
#include "drbd_wrappers.h"
|
|
|
|
/* The request callbacks will be called in irq context by the IDE drivers,
|
|
and in Softirqs/Tasklets/BH context by the SCSI drivers,
|
|
and by the receiver and worker in kernel-thread context.
|
|
Try to get the locking right :) */
|
|
|
|
/*
|
|
* Objects of type struct drbd_request do only exist on a R_PRIMARY node, and are
|
|
* associated with IO requests originating from the block layer above us.
|
|
*
|
|
* There are quite a few things that may happen to a drbd request
|
|
* during its lifetime.
|
|
*
|
|
* It will be created.
|
|
* It will be marked with the intention to be
|
|
* submitted to local disk and/or
|
|
* send via the network.
|
|
*
|
|
* It has to be placed on the transfer log and other housekeeping lists,
|
|
* In case we have a network connection.
|
|
*
|
|
* It may be identified as a concurrent (write) request
|
|
* and be handled accordingly.
|
|
*
|
|
* It may me handed over to the local disk subsystem.
|
|
* It may be completed by the local disk subsystem,
|
|
* either successfully or with io-error.
|
|
* In case it is a READ request, and it failed locally,
|
|
* it may be retried remotely.
|
|
*
|
|
* It may be queued for sending.
|
|
* It may be handed over to the network stack,
|
|
* which may fail.
|
|
* It may be acknowledged by the "peer" according to the wire_protocol in use.
|
|
* this may be a negative ack.
|
|
* It may receive a faked ack when the network connection is lost and the
|
|
* transfer log is cleaned up.
|
|
* Sending may be canceled due to network connection loss.
|
|
* When it finally has outlived its time,
|
|
* corresponding dirty bits in the resync-bitmap may be cleared or set,
|
|
* it will be destroyed,
|
|
* and completion will be signalled to the originator,
|
|
* with or without "success".
|
|
*/
|
|
|
|
enum drbd_req_event {
|
|
created,
|
|
to_be_send,
|
|
to_be_submitted,
|
|
|
|
/* XXX yes, now I am inconsistent...
|
|
* these two are not "events" but "actions"
|
|
* oh, well... */
|
|
queue_for_net_write,
|
|
queue_for_net_read,
|
|
|
|
send_canceled,
|
|
send_failed,
|
|
handed_over_to_network,
|
|
connection_lost_while_pending,
|
|
read_retry_remote_canceled,
|
|
recv_acked_by_peer,
|
|
write_acked_by_peer,
|
|
write_acked_by_peer_and_sis, /* and set_in_sync */
|
|
conflict_discarded_by_peer,
|
|
neg_acked,
|
|
barrier_acked, /* in protocol A and B */
|
|
data_received, /* (remote read) */
|
|
|
|
read_completed_with_error,
|
|
read_ahead_completed_with_error,
|
|
write_completed_with_error,
|
|
completed_ok,
|
|
resend,
|
|
fail_frozen_disk_io,
|
|
restart_frozen_disk_io,
|
|
nothing, /* for tracing only */
|
|
};
|
|
|
|
/* encoding of request states for now. we don't actually need that many bits.
|
|
* we don't need to do atomic bit operations either, since most of the time we
|
|
* need to look at the connection state and/or manipulate some lists at the
|
|
* same time, so we should hold the request lock anyways.
|
|
*/
|
|
enum drbd_req_state_bits {
|
|
/* 210
|
|
* 000: no local possible
|
|
* 001: to be submitted
|
|
* UNUSED, we could map: 011: submitted, completion still pending
|
|
* 110: completed ok
|
|
* 010: completed with error
|
|
*/
|
|
__RQ_LOCAL_PENDING,
|
|
__RQ_LOCAL_COMPLETED,
|
|
__RQ_LOCAL_OK,
|
|
|
|
/* 76543
|
|
* 00000: no network possible
|
|
* 00001: to be send
|
|
* 00011: to be send, on worker queue
|
|
* 00101: sent, expecting recv_ack (B) or write_ack (C)
|
|
* 11101: sent,
|
|
* recv_ack (B) or implicit "ack" (A),
|
|
* still waiting for the barrier ack.
|
|
* master_bio may already be completed and invalidated.
|
|
* 11100: write_acked (C),
|
|
* data_received (for remote read, any protocol)
|
|
* or finally the barrier ack has arrived (B,A)...
|
|
* request can be freed
|
|
* 01100: neg-acked (write, protocol C)
|
|
* or neg-d-acked (read, any protocol)
|
|
* or killed from the transfer log
|
|
* during cleanup after connection loss
|
|
* request can be freed
|
|
* 01000: canceled or send failed...
|
|
* request can be freed
|
|
*/
|
|
|
|
/* if "SENT" is not set, yet, this can still fail or be canceled.
|
|
* if "SENT" is set already, we still wait for an Ack packet.
|
|
* when cleared, the master_bio may be completed.
|
|
* in (B,A) the request object may still linger on the transaction log
|
|
* until the corresponding barrier ack comes in */
|
|
__RQ_NET_PENDING,
|
|
|
|
/* If it is QUEUED, and it is a WRITE, it is also registered in the
|
|
* transfer log. Currently we need this flag to avoid conflicts between
|
|
* worker canceling the request and tl_clear_barrier killing it from
|
|
* transfer log. We should restructure the code so this conflict does
|
|
* no longer occur. */
|
|
__RQ_NET_QUEUED,
|
|
|
|
/* well, actually only "handed over to the network stack".
|
|
*
|
|
* TODO can potentially be dropped because of the similar meaning
|
|
* of RQ_NET_SENT and ~RQ_NET_QUEUED.
|
|
* however it is not exactly the same. before we drop it
|
|
* we must ensure that we can tell a request with network part
|
|
* from a request without, regardless of what happens to it. */
|
|
__RQ_NET_SENT,
|
|
|
|
/* when set, the request may be freed (if RQ_NET_QUEUED is clear).
|
|
* basically this means the corresponding P_BARRIER_ACK was received */
|
|
__RQ_NET_DONE,
|
|
|
|
/* whether or not we know (C) or pretend (B,A) that the write
|
|
* was successfully written on the peer.
|
|
*/
|
|
__RQ_NET_OK,
|
|
|
|
/* peer called drbd_set_in_sync() for this write */
|
|
__RQ_NET_SIS,
|
|
|
|
/* keep this last, its for the RQ_NET_MASK */
|
|
__RQ_NET_MAX,
|
|
|
|
/* Set when this is a write, clear for a read */
|
|
__RQ_WRITE,
|
|
|
|
/* Should call drbd_al_complete_io() for this request... */
|
|
__RQ_IN_ACT_LOG,
|
|
};
|
|
|
|
#define RQ_LOCAL_PENDING (1UL << __RQ_LOCAL_PENDING)
|
|
#define RQ_LOCAL_COMPLETED (1UL << __RQ_LOCAL_COMPLETED)
|
|
#define RQ_LOCAL_OK (1UL << __RQ_LOCAL_OK)
|
|
|
|
#define RQ_LOCAL_MASK ((RQ_LOCAL_OK << 1)-1) /* 0x07 */
|
|
|
|
#define RQ_NET_PENDING (1UL << __RQ_NET_PENDING)
|
|
#define RQ_NET_QUEUED (1UL << __RQ_NET_QUEUED)
|
|
#define RQ_NET_SENT (1UL << __RQ_NET_SENT)
|
|
#define RQ_NET_DONE (1UL << __RQ_NET_DONE)
|
|
#define RQ_NET_OK (1UL << __RQ_NET_OK)
|
|
#define RQ_NET_SIS (1UL << __RQ_NET_SIS)
|
|
|
|
/* 0x1f8 */
|
|
#define RQ_NET_MASK (((1UL << __RQ_NET_MAX)-1) & ~RQ_LOCAL_MASK)
|
|
|
|
#define RQ_WRITE (1UL << __RQ_WRITE)
|
|
#define RQ_IN_ACT_LOG (1UL << __RQ_IN_ACT_LOG)
|
|
|
|
/* For waking up the frozen transfer log mod_req() has to return if the request
|
|
should be counted in the epoch object*/
|
|
#define MR_WRITE_SHIFT 0
|
|
#define MR_WRITE (1 << MR_WRITE_SHIFT)
|
|
#define MR_READ_SHIFT 1
|
|
#define MR_READ (1 << MR_READ_SHIFT)
|
|
|
|
/* epoch entries */
|
|
static inline
|
|
struct hlist_head *ee_hash_slot(struct drbd_conf *mdev, sector_t sector)
|
|
{
|
|
BUG_ON(mdev->ee_hash_s == 0);
|
|
return mdev->ee_hash +
|
|
((unsigned int)(sector>>HT_SHIFT) % mdev->ee_hash_s);
|
|
}
|
|
|
|
/* transfer log (drbd_request objects) */
|
|
static inline
|
|
struct hlist_head *tl_hash_slot(struct drbd_conf *mdev, sector_t sector)
|
|
{
|
|
BUG_ON(mdev->tl_hash_s == 0);
|
|
return mdev->tl_hash +
|
|
((unsigned int)(sector>>HT_SHIFT) % mdev->tl_hash_s);
|
|
}
|
|
|
|
/* application reads (drbd_request objects) */
|
|
static struct hlist_head *ar_hash_slot(struct drbd_conf *mdev, sector_t sector)
|
|
{
|
|
return mdev->app_reads_hash
|
|
+ ((unsigned int)(sector) % APP_R_HSIZE);
|
|
}
|
|
|
|
/* when we receive the answer for a read request,
|
|
* verify that we actually know about it */
|
|
static inline struct drbd_request *_ar_id_to_req(struct drbd_conf *mdev,
|
|
u64 id, sector_t sector)
|
|
{
|
|
struct hlist_head *slot = ar_hash_slot(mdev, sector);
|
|
struct hlist_node *n;
|
|
struct drbd_request *req;
|
|
|
|
hlist_for_each_entry(req, n, slot, colision) {
|
|
if ((unsigned long)req == (unsigned long)id) {
|
|
D_ASSERT(req->sector == sector);
|
|
return req;
|
|
}
|
|
}
|
|
return NULL;
|
|
}
|
|
|
|
static inline void drbd_req_make_private_bio(struct drbd_request *req, struct bio *bio_src)
|
|
{
|
|
struct bio *bio;
|
|
bio = bio_clone(bio_src, GFP_NOIO); /* XXX cannot fail?? */
|
|
|
|
req->private_bio = bio;
|
|
|
|
bio->bi_private = req;
|
|
bio->bi_end_io = drbd_endio_pri;
|
|
bio->bi_next = NULL;
|
|
}
|
|
|
|
static inline struct drbd_request *drbd_req_new(struct drbd_conf *mdev,
|
|
struct bio *bio_src)
|
|
{
|
|
struct drbd_request *req =
|
|
mempool_alloc(drbd_request_mempool, GFP_NOIO);
|
|
if (likely(req)) {
|
|
drbd_req_make_private_bio(req, bio_src);
|
|
|
|
req->rq_state = bio_data_dir(bio_src) == WRITE ? RQ_WRITE : 0;
|
|
req->mdev = mdev;
|
|
req->master_bio = bio_src;
|
|
req->epoch = 0;
|
|
req->sector = bio_src->bi_sector;
|
|
req->size = bio_src->bi_size;
|
|
req->start_time = jiffies;
|
|
INIT_HLIST_NODE(&req->colision);
|
|
INIT_LIST_HEAD(&req->tl_requests);
|
|
INIT_LIST_HEAD(&req->w.list);
|
|
}
|
|
return req;
|
|
}
|
|
|
|
static inline void drbd_req_free(struct drbd_request *req)
|
|
{
|
|
mempool_free(req, drbd_request_mempool);
|
|
}
|
|
|
|
static inline int overlaps(sector_t s1, int l1, sector_t s2, int l2)
|
|
{
|
|
return !((s1 + (l1>>9) <= s2) || (s1 >= s2 + (l2>>9)));
|
|
}
|
|
|
|
/* Short lived temporary struct on the stack.
|
|
* We could squirrel the error to be returned into
|
|
* bio->bi_size, or similar. But that would be too ugly. */
|
|
struct bio_and_error {
|
|
struct bio *bio;
|
|
int error;
|
|
};
|
|
|
|
extern void _req_may_be_done(struct drbd_request *req,
|
|
struct bio_and_error *m);
|
|
extern int __req_mod(struct drbd_request *req, enum drbd_req_event what,
|
|
struct bio_and_error *m);
|
|
extern void complete_master_bio(struct drbd_conf *mdev,
|
|
struct bio_and_error *m);
|
|
|
|
/* 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)
|
|
{
|
|
struct drbd_conf *mdev = req->mdev;
|
|
struct bio_and_error m;
|
|
int rv;
|
|
|
|
/* __req_mod possibly frees req, do not touch req after that! */
|
|
rv = __req_mod(req, what, &m);
|
|
if (m.bio)
|
|
complete_master_bio(mdev, &m);
|
|
|
|
return rv;
|
|
}
|
|
|
|
/* completion of master bio is outside of spinlock.
|
|
* If you need it irqsave, do it your self!
|
|
* Which means: don't use from bio endio callback. */
|
|
static inline int req_mod(struct drbd_request *req,
|
|
enum drbd_req_event what)
|
|
{
|
|
struct drbd_conf *mdev = req->mdev;
|
|
struct bio_and_error m;
|
|
int rv;
|
|
|
|
spin_lock_irq(&mdev->req_lock);
|
|
rv = __req_mod(req, what, &m);
|
|
spin_unlock_irq(&mdev->req_lock);
|
|
|
|
if (m.bio)
|
|
complete_master_bio(mdev, &m);
|
|
|
|
return rv;
|
|
}
|
|
#endif
|