/*
drbd_actlog.c
This file is part of DRBD by Philipp Reisner and Lars Ellenberg.
Copyright (C) 2003-2008, LINBIT Information Technologies GmbH.
Copyright (C) 2003-2008, Philipp Reisner <philipp.reisner@linbit.com>.
Copyright (C) 2003-2008, Lars Ellenberg <lars.ellenberg@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.
*/
#include <linux/slab.h>
#include <linux/drbd.h>
#include "drbd_int.h"
#include "drbd_wrappers.h"
/* We maintain a trivial checksum in our on disk activity log.
* With that we can ensure correct operation even when the storage
* device might do a partial (last) sector write while losing power.
*/
struct __packed al_transaction {
u32 magic;
u32 tr_number;
struct __packed {
u32 pos;
u32 extent; } updates[1 + AL_EXTENTS_PT];
u32 xor_sum;
};
struct update_odbm_work {
struct drbd_work w;
unsigned int enr;
};
struct update_al_work {
struct drbd_work w;
struct lc_element *al_ext;
struct completion event;
unsigned int enr;
/* if old_enr != LC_FREE, write corresponding bitmap sector, too */
unsigned int old_enr;
};
struct drbd_atodb_wait {
atomic_t count;
struct completion io_done;
struct drbd_conf *mdev;
int error;
};
int w_al_write_transaction(struct drbd_conf *, struct drbd_work *, int);
void *drbd_md_get_buffer(struct drbd_conf *mdev)
{
int r;
wait_event(mdev->misc_wait,
(r = atomic_cmpxchg(&mdev->md_io_in_use, 0, 1)) == 0 ||
mdev->state.disk <= D_FAILED);
return r ? NULL : page_address(mdev->md_io_page);
}
void drbd_md_put_buffer(struct drbd_conf *mdev)
{
if (atomic_dec_and_test(&mdev->md_io_in_use))
wake_up(&mdev->misc_wait);
}
static bool md_io_allowed(struct drbd_conf *mdev)
{
enum drbd_disk_state ds = mdev->state.disk;
return ds >= D_NEGOTIATING || ds == D_ATTACHING;
}
void wait_until_done_or_disk_failure(struct drbd_conf *mdev, struct 