Commit b5bc8e08 authored by Lars Ellenberg's avatar Lars Ellenberg Committed by Jens Axboe
Browse files

drbd: split drbd_al_begin_io into fastpath, prepare, and commit 



Signed-off-by: default avatarPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: default avatarLars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 113fef9e

drivers/block/drbd/drbd_actlog.c

+71 −33
Original line number Diff line number Diff line
@@ -104,7 +104,6 @@ struct update_al_work { 
	int err;

};



static int al_write_transaction(struct drbd_conf *mdev, bool delegate);



void *drbd_md_get_buffer(struct drbd_conf *mdev)

{
@@ -246,30 +245,37 @@ static struct lc_element *_al_get(struct drbd_conf *mdev, unsigned int enr) 
	return al_ext;

}



/*

 * @delegate:   delegate activity log I/O to the worker thread

 */

void drbd_al_begin_io(struct drbd_conf *mdev, struct drbd_interval *i, bool delegate)

bool drbd_al_begin_io_fastpath(struct drbd_conf *mdev, struct drbd_interval *i)

{

	/* for bios crossing activity log extent boundaries,

	 * we may need to activate two extents in one go */

	unsigned first = i->sector >> (AL_EXTENT_SHIFT-9);

	unsigned last = i->size == 0 ? first : (i->sector + (i->size >> 9) - 1) >> (AL_EXTENT_SHIFT-9);

	unsigned enr;

	bool need_transaction = false;

	bool locked = false;

	bool fastpath_ok = true;



	/* When called through generic_make_request(), we must delegate

	 * activity log I/O to the worker thread: a further request

	 * submitted via generic_make_request() within the same task

	 * would be queued on current->bio_list, and would only start

	 * after this function returns (see generic_make_request()).

	 *

	 * However, if we *are* the worker, we must not delegate to ourselves.

	 */

	D_ASSERT((unsigned)(last - first) <= 1);

	D_ASSERT(atomic_read(&mdev->local_cnt) > 0);



	if (delegate)

		BUG_ON(current == mdev->tconn->worker.task);

	/* FIXME figure out a fast path for bios crossing AL extent boundaries */

	if (first != last)

		return false;



	spin_lock_irq(&mdev->al_lock);

	fastpath_ok =

		lc_find(mdev->resync, first/AL_EXT_PER_BM_SECT) == NULL &&

		lc_try_get(mdev->act_log, first) != NULL;

	spin_unlock_irq(&mdev->al_lock);

	return fastpath_ok;

}



bool drbd_al_begin_io_prepare(struct drbd_conf *mdev, struct drbd_interval *i)

{

	/* for bios crossing activity log extent boundaries,

	 * we may need to activate two extents in one go */

	unsigned first = i->sector >> (AL_EXTENT_SHIFT-9);

	unsigned last = i->size == 0 ? first : (i->sector + (i->size >> 9) - 1) >> (AL_EXTENT_SHIFT-9);

	unsigned enr;

	bool need_transaction = false;



	D_ASSERT(first <= last);

	D_ASSERT(atomic_read(&mdev->local_cnt) > 0);
@@ -280,11 +286,28 @@ void drbd_al_begin_io(struct drbd_conf *mdev, struct drbd_interval *i, bool dele 
		if (al_ext->lc_number != enr)

			need_transaction = true;

	}

	return need_transaction;

}



	/* If *this* request was to an already active extent,

	 * we're done, even if there are pending changes. */

	if (!need_transaction)

		return;

static int al_write_transaction(struct drbd_conf *mdev, bool delegate);



/* When called through generic_make_request(), we must delegate

 * activity log I/O to the worker thread: a further request

 * submitted via generic_make_request() within the same task

 * would be queued on current->bio_list, and would only start

 * after this function returns (see generic_make_request()).

 *

 * However, if we *are* the worker, we must not delegate to ourselves.

 */



/*

 * @delegate:   delegate activity log I/O to the worker thread

 */

void drbd_al_begin_io_commit(struct drbd_conf *mdev, bool delegate)

{

	bool locked = false;



	BUG_ON(delegate && current == mdev->tconn->worker.task);



	/* Serialize multiple transactions.

	 * This uses test_and_set_bit, memory barrier is implicit.
@@ -303,11 +326,8 @@ void drbd_al_begin_io(struct drbd_conf *mdev, struct drbd_interval *i, bool dele 
			write_al_updates = rcu_dereference(mdev->ldev->disk_conf)->al_updates;

			rcu_read_unlock();



			if (write_al_updates) {

			if (write_al_updates)

				al_write_transaction(mdev, delegate);

				mdev->al_writ_cnt++;

			}



			spin_lock_irq(&mdev->al_lock);

			/* FIXME

			if (err)
@@ -321,6 +341,17 @@ void drbd_al_begin_io(struct drbd_conf *mdev, struct drbd_interval *i, bool dele 
	}

}



/*

 * @delegate:   delegate activity log I/O to the worker thread

 */

void drbd_al_begin_io(struct drbd_conf *mdev, struct drbd_interval *i, bool delegate)

{

	BUG_ON(delegate && current == mdev->tconn->worker.task);



	if (drbd_al_begin_io_prepare(mdev, i))

		drbd_al_begin_io_commit(mdev, delegate);

}



void drbd_al_complete_io(struct drbd_conf *mdev, struct drbd_interval *i)

{

	/* for bios crossing activity log extent boundaries,
@@ -478,15 +509,22 @@ _al_write_transaction(struct drbd_conf *mdev) 
	crc = crc32c(0, buffer, 4096);

	buffer->crc32c = cpu_to_be32(crc);



	/* normal execution path goes through all three branches */

	if (drbd_bm_write_hinted(mdev))

		err = -EIO;

		/* drbd_chk_io_error done already */

	else if (drbd_md_sync_page_io(mdev, mdev->ldev, sector, WRITE)) {

	else {

		bool write_al_updates;

		rcu_read_lock();

		write_al_updates = rcu_dereference(mdev->ldev->disk_conf)->al_updates;

		rcu_read_unlock();

		if (write_al_updates) {

			if (drbd_md_sync_page_io(mdev, mdev->ldev, sector, WRITE)) {

				err = -EIO;

				drbd_chk_io_error(mdev, 1, DRBD_META_IO_ERROR);

			} else {

				mdev->al_tr_number++;

				mdev->al_writ_cnt++;

			}

		}

	}



	drbd_md_put_buffer(mdev);

drivers/block/drbd/drbd_int.h

+1 −0
Original line number Diff line number Diff line
@@ -1611,6 +1611,7 @@ extern const char *drbd_conn_str(enum drbd_conns s); 
extern const char *drbd_role_str(enum drbd_role s);



/* drbd_actlog.c */

extern bool drbd_al_begin_io_fastpath(struct drbd_conf *mdev, struct drbd_interval *i);

extern void drbd_al_begin_io(struct drbd_conf *mdev, struct drbd_interval *i, bool delegate);

extern void drbd_al_complete_io(struct drbd_conf *mdev, struct drbd_interval *i);

extern void drbd_rs_complete_io(struct drbd_conf *mdev, sector_t sector);