Commit e1711731 authored by Philipp Reisner's avatar Philipp Reisner
Browse files

drbd: Replaced md_io_mutex by an atomic: md_io_in_use 



The new function drbd_md_get_buffer() aborts waiting for the buffer
in case the disk failes in the meantime.

Signed-off-by: default avatarPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: default avatarLars Ellenberg <lars.ellenberg@linbit.com>
parent cc94c650

drivers/block/drbd/drbd_actlog.c

+34 −10
Original line number Diff line number Diff line
@@ -65,6 +65,23 @@ struct drbd_atodb_wait { 


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 int _drbd_md_sync_page_io(struct drbd_conf *mdev,

				 struct drbd_backing_dev *bdev,

				 struct page *page, sector_t sector,
@@ -90,6 +107,7 @@ static int _drbd_md_sync_page_io(struct drbd_conf *mdev, 
	bio->bi_end_io = drbd_md_io_complete;

	bio->bi_rw = rw;



	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
@@ -109,7 +127,7 @@ int drbd_md_sync_page_io(struct drbd_conf *mdev, struct drbd_backing_dev *bdev, 
	int offset = 0;

	struct page *iop = mdev->md_io_page;



	D_ASSERT(mutex_is_locked(&mdev->md_io_mutex));

	D_ASSERT(atomic_read(&mdev->md_io_in_use) == 1);



	BUG_ON(!bdev->md_bdev);
@@ -326,8 +344,13 @@ w_al_write_transaction(struct drbd_conf *mdev, struct drbd_work *w, int unused) 
		return 1;

	}



	mutex_lock(&mdev->md_io_mutex); /* protects md_io_buffer, al_tr_cycle, ... */

	buffer = (struct al_transaction *)page_address(mdev->md_io_page);

	buffer = drbd_md_get_buffer(mdev); /* protects md_io_buffer, al_tr_cycle, ... */

	if (!buffer) {

		dev_err(DEV, "disk failed while waiting for md_io buffer\n");

		complete(&((struct update_al_work *)w)->event);

		put_ldev(mdev);

		return 1;

	}



	buffer->magic = __constant_cpu_to_be32(DRBD_MAGIC);

	buffer->tr_number = cpu_to_be32(mdev->al_tr_number);
@@ -372,7 +395,7 @@ w_al_write_transaction(struct drbd_conf *mdev, struct drbd_work *w, int unused) 
	D_ASSERT(mdev->al_tr_pos < MD_AL_MAX_SIZE);

	mdev->al_tr_number++;



	mutex_unlock(&mdev->md_io_mutex);

	drbd_md_put_buffer(mdev);



	complete(&((struct update_al_work *)w)->event);

	put_ldev(mdev);
@@ -441,8 +464,9 @@ int drbd_al_read_log(struct drbd_conf *mdev, struct drbd_backing_dev *bdev) 
	/* lock out all other meta data io for now,

	 * and make sure the page is mapped.

	 */

	mutex_lock(&mdev->md_io_mutex);

	buffer = page_address(mdev->md_io_page);

	buffer = drbd_md_get_buffer(mdev);

	if (!buffer)

		return 0;



	/* Find the valid transaction in the log */

	for (i = 0; i <= mx; i++) {
@@ -450,7 +474,7 @@ int drbd_al_read_log(struct drbd_conf *mdev, struct drbd_backing_dev *bdev) 
		if (rv == 0)

			continue;

		if (rv == -1) {

			mutex_unlock(&mdev->md_io_mutex);

			drbd_md_put_buffer(mdev);

			return 0;

		}

		cnr = be32_to_cpu(buffer->tr_number);
@@ -476,7 +500,7 @@ int drbd_al_read_log(struct drbd_conf *mdev, struct drbd_backing_dev *bdev) 


	if (!found_valid) {

		dev_warn(DEV, "No usable activity log found.\n");

		mutex_unlock(&mdev->md_io_mutex);

		drbd_md_put_buffer(mdev);

		return 1;

	}
@@ -491,7 +515,7 @@ int drbd_al_read_log(struct drbd_conf *mdev, struct drbd_backing_dev *bdev) 
		rv = drbd_al_read_tr(mdev, bdev, buffer, i);

		ERR_IF(rv == 0) goto cancel;

		if (rv == -1) {

			mutex_unlock(&mdev->md_io_mutex);

			drbd_md_put_buffer(mdev);

			return 0;

		}
@@ -532,7 +556,7 @@ int drbd_al_read_log(struct drbd_conf *mdev, struct drbd_backing_dev *bdev) 
		mdev->al_tr_pos = 0;



	/* ok, we are done with it */

	mutex_unlock(&mdev->md_io_mutex);

	drbd_md_put_buffer(mdev);



	dev_info(DEV, "Found %d transactions (%d active extents) in activity log.\n",

	     transactions, active_extents);

drivers/block/drbd/drbd_int.h

+4 −2
Original line number Diff line number Diff line
@@ -1095,7 +1095,7 @@ struct drbd_conf { 
	struct page *md_io_page;	/* one page buffer for md_io */

	struct page *md_io_tmpp;	/* for logical_block_size != 512 */

	struct drbd_md_io md_io;

	struct mutex md_io_mutex;	/* protects the md_io, md_io_page and md_io_tmpp */

	atomic_t md_io_in_use;		/* protects the md_io, md_io_page and md_io_tmpp */

	spinlock_t al_lock;

	wait_queue_head_t al_wait;

	struct lru_cache *act_log;	/* activity log */
@@ -1537,6 +1537,8 @@ extern void resume_next_sg(struct drbd_conf *mdev); 
extern void suspend_other_sg(struct drbd_conf *mdev);

extern int drbd_resync_finished(struct drbd_conf *mdev);

/* maybe rather drbd_main.c ? */

extern void *drbd_md_get_buffer(struct drbd_conf *mdev);

extern void drbd_md_put_buffer(struct drbd_conf *mdev);

extern int drbd_md_sync_page_io(struct drbd_conf *mdev,

				struct drbd_backing_dev *bdev, sector_t sector, int rw);

extern void drbd_ov_oos_found(struct drbd_conf*, sector_t, int);

drivers/block/drbd/drbd_main.c

+12 −7
Original line number Diff line number Diff line
@@ -3043,8 +3043,8 @@ void drbd_init_set_defaults(struct drbd_conf *mdev) 
	atomic_set(&mdev->rs_sect_in, 0);

	atomic_set(&mdev->rs_sect_ev, 0);

	atomic_set(&mdev->ap_in_flight, 0);

	atomic_set(&mdev->md_io_in_use, 0);



	mutex_init(&mdev->md_io_mutex);

	mutex_init(&mdev->data.mutex);

	mutex_init(&mdev->meta.mutex);

	sema_init(&mdev->data.work.s, 0);
@@ -3722,8 +3722,10 @@ void drbd_md_sync(struct drbd_conf *mdev) 
	if (!get_ldev_if_state(mdev, D_FAILED))

		return;



	mutex_lock(&mdev->md_io_mutex);

	buffer = (struct meta_data_on_disk *)page_address(mdev->md_io_page);

	buffer = drbd_md_get_buffer(mdev);

	if (!buffer)

		goto out;



	memset(buffer, 0, 512);



	buffer->la_size = cpu_to_be64(drbd_get_capacity(mdev->this_bdev));
@@ -3754,7 +3756,8 @@ void drbd_md_sync(struct drbd_conf *mdev) 
	 * since we updated it on metadata. */

	mdev->ldev->md.la_size_sect = drbd_get_capacity(mdev->this_bdev);



	mutex_unlock(&mdev->md_io_mutex);

	drbd_md_put_buffer(mdev);

out:

	put_ldev(mdev);

}
@@ -3774,8 +3777,9 @@ int drbd_md_read(struct drbd_conf *mdev, struct drbd_backing_dev *bdev) 
	if (!get_ldev_if_state(mdev, D_ATTACHING))

		return ERR_IO_MD_DISK;



	mutex_lock(&mdev->md_io_mutex);

	buffer = (struct meta_data_on_disk *)page_address(mdev->md_io_page);

	buffer = drbd_md_get_buffer(mdev);

	if (!buffer)

		goto out;



	if (!drbd_md_sync_page_io(mdev, bdev, bdev->md.md_offset, READ)) {

		/* NOTE: can't do normal error processing here as this is
@@ -3836,7 +3840,8 @@ int drbd_md_read(struct drbd_conf *mdev, struct drbd_backing_dev *bdev) 
		mdev->sync_conf.al_extents = 127;



 err:

	mutex_unlock(&mdev->md_io_mutex);

	drbd_md_put_buffer(mdev);

 out:

	put_ldev(mdev);



	return rv;

drivers/block/drbd/drbd_worker.c

+1 −0
Original line number Diff line number Diff line
@@ -78,6 +78,7 @@ void drbd_md_io_complete(struct bio *bio, int error) 
	md_io->error = error;



	complete(&md_io->event);

	drbd_md_put_buffer(mdev);

}



/* reads on behalf of the partner,