path: root/drivers/block/drbd/drbd_actlog.c

/*
   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 drbd_backing_dev *bdev,
				     unsigned int *done)
{
	long dt = bdev->dc.disk_timeout * HZ / 10;
	if (dt == 0)
		dt = MAX_SCHEDULE_TIMEOUT;

	dt = wait_event_timeout(mdev->misc_wait, *done || !md_io_allowed(mdev), dt);
	if (dt == 0)
		dev_err(DEV, "meta-data IO operation timed out\n");
}

static int _drbd_md_sync_page_io(struct drbd_conf *mdev,
				 struct drbd_backing_dev *bdev,
				 struct page *page, sector_t sector,
				 int rw, int size)
{
	struct bio *bio;
	int ok;

	mdev->md_io.done = 0;
	mdev->md_io.error = -ENODEV;

	if ((rw & WRITE) && !test_bit(MD_NO_FUA, &mdev->flags))
		rw |= REQ_FUA | REQ_FLUSH;
	rw |= REQ_SYNC;

	bio = bio_alloc_drbd(GFP_NOIO);
	bio->bi_bdev = bdev->md_bdev;
	bio->bi_sector = sector;
	ok = (bio_add_page(bio, page, size, 0) == size);
	if (!ok)
		goto out;
	bio->bi_private = &mdev->md_io;
	bio->bi_end_io = drbd_md_io_complete;
	bio->bi_rw = rw;

	if (!get_ldev_if_state(mdev, D_ATTACHING)) {  /* Corresponding put_ldev in drbd_md_io_complete() */
		dev_err(DEV, "ASSERT FAILED: get_ldev_if_state() == 1 in _drbd_md_sync_page_io()\n");
		ok = 0;
		goto out;
	}

	bio_get(bio); /* one bio_put() is in the completion handler */
	atomic_inc(&mdev->md_io_in_use); /* drbd_md_put_buffer() is in the completion handler */
	if (drbd_insert_fault(mdev, (rw & WRITE) ? DRBD_FAULT_MD_WR : DRBD_FAULT_MD_RD))
		bio_endio(bio, -EIO);
	else
		submit_bio(rw, bio);
	wait_until_done_or_disk_failure(mdev, bdev, &mdev->md_io.done);
	ok = bio_flagged(bio, BIO_UPTODATE) && mdev->md_io.error == 0;

 out:
	bio_put(bio);
	return ok;
}

int drbd_md_sync_page_io(struct drbd_conf *mdev, struct drbd_backing_dev *bdev,
			 sector_t sector, int rw)
{
	int logical_block_size, mask, ok;
	int offset = 0;
	struct page *iop = mdev->md_io_page;