Commit b559292e authored by Philipp Reisner's avatar Philipp Reisner Committed by Mark Fasheh
Browse files

[PATCH] ocfs2 heartbeat: clean up bio submission code 



As was already pointed out Mathieu Avila on Thu, 07 Sep 2006 03:15:25 -0700
that OCFS2 is expecting bio_add_page() to add pages to BIOs in an easily
predictable manner.

That is not true, especially for devices with own merge_bvec_fn().

Therefore OCFS2's heartbeat code is very likely to fail on such devices.

Move the bio_put() call into the bio's bi_end_io() function. This makes the
whole idea of trying to predict the behaviour of bio_add_page() unnecessary.
Removed compute_max_sectors() and o2hb_compute_request_limits().

Signed-off-by: default avatarPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: default avatarMark Fasheh <mark.fasheh@oracle.com>
parent 925037bc

fs/ocfs2/cluster/heartbeat.c

+31 −127
Original line number Diff line number Diff line
@@ -184,10 +184,9 @@ static void o2hb_disarm_write_timeout(struct o2hb_region *reg) 
	flush_scheduled_work();

}



static inline void o2hb_bio_wait_init(struct o2hb_bio_wait_ctxt *wc,

				      unsigned int num_ios)

static inline void o2hb_bio_wait_init(struct o2hb_bio_wait_ctxt *wc)

{

	atomic_set(&wc->wc_num_reqs, num_ios);

	atomic_set(&wc->wc_num_reqs, 1);

	init_completion(&wc->wc_io_complete);

	wc->wc_error = 0;

}
@@ -212,6 +211,7 @@ static void o2hb_wait_on_io(struct o2hb_region *reg, 
	struct address_space *mapping = reg->hr_bdev->bd_inode->i_mapping;



	blk_run_address_space(mapping);

	o2hb_bio_wait_dec(wc, 1);



	wait_for_completion(&wc->wc_io_complete);

}
@@ -231,6 +231,7 @@ static int o2hb_bio_end_io(struct bio *bio, 
		return 1;



	o2hb_bio_wait_dec(wc, 1);

	bio_put(bio);

	return 0;

}
@@ -238,23 +239,22 @@ static int o2hb_bio_end_io(struct bio *bio, 
 * start_slot. */

static struct bio *o2hb_setup_one_bio(struct o2hb_region *reg,

				      struct o2hb_bio_wait_ctxt *wc,

				      unsigned int start_slot,

				      unsigned int num_slots)

				      unsigned int *current_slot,

				      unsigned int max_slots)

{

	int i, nr_vecs, len, first_page, last_page;

	int len, current_page;

	unsigned int vec_len, vec_start;

	unsigned int bits = reg->hr_block_bits;

	unsigned int spp = reg->hr_slots_per_page;

	unsigned int cs = *current_slot;

	struct bio *bio;

	struct page *page;



	nr_vecs = (num_slots + spp - 1) / spp;



	/* Testing has shown this allocation to take long enough under

	 * GFP_KERNEL that the local node can get fenced. It would be

	 * nicest if we could pre-allocate these bios and avoid this

	 * all together. */

	bio = bio_alloc(GFP_ATOMIC, nr_vecs);

	bio = bio_alloc(GFP_ATOMIC, 16);

	if (!bio) {

		mlog(ML_ERROR, "Could not alloc slots BIO!\n");

		bio = ERR_PTR(-ENOMEM);
@@ -262,137 +262,53 @@ static struct bio *o2hb_setup_one_bio(struct o2hb_region *reg, 
	}



	/* Must put everything in 512 byte sectors for the bio... */

	bio->bi_sector = (reg->hr_start_block + start_slot) << (bits - 9);

	bio->bi_sector = (reg->hr_start_block + cs) << (bits - 9);

	bio->bi_bdev = reg->hr_bdev;

	bio->bi_private = wc;

	bio->bi_end_io = o2hb_bio_end_io;



	first_page = start_slot / spp;

	last_page = first_page + nr_vecs;

	vec_start = (start_slot << bits) % PAGE_CACHE_SIZE;

	for(i = first_page; i < last_page; i++) {

		page = reg->hr_slot_data[i];

	vec_start = (cs << bits) % PAGE_CACHE_SIZE;

	while(cs < max_slots) {

		current_page = cs / spp;

		page = reg->hr_slot_data[current_page];



		vec_len = PAGE_CACHE_SIZE;

		/* last page might be short */

		if (((i + 1) * spp) > (start_slot + num_slots))

			vec_len = ((num_slots + start_slot) % spp) << bits;

		vec_len -=  vec_start;

		vec_len = min(PAGE_CACHE_SIZE,

			      (max_slots-cs) * (PAGE_CACHE_SIZE/spp) );



		mlog(ML_HB_BIO, "page %d, vec_len = %u, vec_start = %u\n",

		     i, vec_len, vec_start);

		     current_page, vec_len, vec_start);



		len = bio_add_page(bio, page, vec_len, vec_start);

		if (len != vec_len) {

			bio_put(bio);

			bio = ERR_PTR(-EIO);



			mlog(ML_ERROR, "Error adding page to bio i = %d, "

			     "vec_len = %u, len = %d\n, start = %u\n",

			     i, vec_len, len, vec_start);

			goto bail;

		}

		if (len != vec_len) break;



		cs += vec_len / (PAGE_CACHE_SIZE/spp);

		vec_start = 0;

	}



bail:

	*current_slot = cs;

	return bio;

}



/*

 * Compute the maximum number of sectors the bdev can handle in one bio,

 * as a power of two.

 *

 * Stolen from oracleasm, thanks Joel!

 */

static int compute_max_sectors(struct block_device *bdev)

{

	int max_pages, max_sectors, pow_two_sectors;



	struct request_queue *q;



	q = bdev_get_queue(bdev);

	max_pages = q->max_sectors >> (PAGE_SHIFT - 9);

	if (max_pages > BIO_MAX_PAGES)

		max_pages = BIO_MAX_PAGES;

	if (max_pages > q->max_phys_segments)

		max_pages = q->max_phys_segments;

	if (max_pages > q->max_hw_segments)

		max_pages = q->max_hw_segments;

	max_pages--; /* Handle I/Os that straddle a page */



	if (max_pages) {

		max_sectors = max_pages << (PAGE_SHIFT - 9);

	} else {

		/* If BIO contains 1 or less than 1 page. */

		max_sectors = q->max_sectors;

	}

	/* Why is fls() 1-based???? */

	pow_two_sectors = 1 << (fls(max_sectors) - 1);



	return pow_two_sectors;

}



static inline void o2hb_compute_request_limits(struct o2hb_region *reg,

					       unsigned int num_slots,

					       unsigned int *num_bios,

					       unsigned int *slots_per_bio)

{

	unsigned int max_sectors, io_sectors;



	max_sectors = compute_max_sectors(reg->hr_bdev);



	io_sectors = num_slots << (reg->hr_block_bits - 9);



	*num_bios = (io_sectors + max_sectors - 1) / max_sectors;

	*slots_per_bio = max_sectors >> (reg->hr_block_bits - 9);



	mlog(ML_HB_BIO, "My io size is %u sectors for %u slots. This "

	     "device can handle %u sectors of I/O\n", io_sectors, num_slots,

	     max_sectors);

	mlog(ML_HB_BIO, "Will need %u bios holding %u slots each\n",

	     *num_bios, *slots_per_bio);

}



static int o2hb_read_slots(struct o2hb_region *reg,

			   unsigned int max_slots)

{

	unsigned int num_bios, slots_per_bio, start_slot, num_slots;

	int i, status;

	unsigned int current_slot=0;

	int status;

	struct o2hb_bio_wait_ctxt wc;

	struct bio **bios;

	struct bio *bio;



	o2hb_compute_request_limits(reg, max_slots, &num_bios, &slots_per_bio);



	bios = kcalloc(num_bios, sizeof(struct bio *), GFP_KERNEL);

	if (!bios) {

		status = -ENOMEM;

		mlog_errno(status);

		return status;

	}



	o2hb_bio_wait_init(&wc, num_bios);



	num_slots = slots_per_bio;

	for(i = 0; i < num_bios; i++) {

		start_slot = i * slots_per_bio;

	o2hb_bio_wait_init(&wc);



		/* adjust num_slots at last bio */

		if (max_slots < (start_slot + num_slots))

			num_slots = max_slots - start_slot;



		bio = o2hb_setup_one_bio(reg, &wc, start_slot, num_slots);

	while(current_slot < max_slots) {

		bio = o2hb_setup_one_bio(reg, &wc, &current_slot, max_slots);

		if (IS_ERR(bio)) {

			o2hb_bio_wait_dec(&wc, num_bios - i);



			status = PTR_ERR(bio);

			mlog_errno(status);

			goto bail_and_wait;

		}

		bios[i] = bio;



		atomic_inc(&wc.wc_num_reqs);

		submit_bio(READ, bio);

	}
@@ -403,38 +319,30 @@ bail_and_wait: 
	if (wc.wc_error && !status)

		status = wc.wc_error;



	if (bios) {

		for(i = 0; i < num_bios; i++)

			if (bios[i])

				bio_put(bios[i]);

		kfree(bios);

	}



	return status;

}



static int o2hb_issue_node_write(struct o2hb_region *reg,

				 struct bio **write_bio,

				 struct o2hb_bio_wait_ctxt *write_wc)

{

	int status;

	unsigned int slot;

	struct bio *bio;



	o2hb_bio_wait_init(write_wc, 1);

	o2hb_bio_wait_init(write_wc);



	slot = o2nm_this_node();



	bio = o2hb_setup_one_bio(reg, write_wc, slot, 1);

	bio = o2hb_setup_one_bio(reg, write_wc, &slot, slot+1);

	if (IS_ERR(bio)) {

		status = PTR_ERR(bio);

		mlog_errno(status);

		goto bail;

	}



	atomic_inc(&write_wc->wc_num_reqs);

	submit_bio(WRITE, bio);



	*write_bio = bio;

	status = 0;

bail:

	return status;
@@ -826,7 +734,6 @@ static int o2hb_do_disk_heartbeat(struct o2hb_region *reg) 
{

	int i, ret, highest_node, change = 0;

	unsigned long configured_nodes[BITS_TO_LONGS(O2NM_MAX_NODES)];

	struct bio *write_bio;

	struct o2hb_bio_wait_ctxt write_wc;



	ret = o2nm_configured_node_map(configured_nodes,
@@ -864,7 +771,7 @@ static int o2hb_do_disk_heartbeat(struct o2hb_region *reg) 


	/* And fire off the write. Note that we don't wait on this I/O

	 * until later. */

	ret = o2hb_issue_node_write(reg, &write_bio, &write_wc);

	ret = o2hb_issue_node_write(reg, &write_wc);

	if (ret < 0) {

		mlog_errno(ret);

		return ret;
@@ -882,7 +789,6 @@ static int o2hb_do_disk_heartbeat(struct o2hb_region *reg) 
	 * people we find in our steady state have seen us.

	 */

	o2hb_wait_on_io(reg, &write_wc);

	bio_put(write_bio);

	if (write_wc.wc_error) {

		/* Do not re-arm the write timeout on I/O error - we

		 * can't be sure that the new block ever made it to
@@ -943,7 +849,6 @@ static int o2hb_thread(void *data) 
{

	int i, ret;

	struct o2hb_region *reg = data;

	struct bio *write_bio;

	struct o2hb_bio_wait_ctxt write_wc;

	struct timeval before_hb, after_hb;

	unsigned int elapsed_msec;
@@ -993,10 +898,9 @@ static int o2hb_thread(void *data) 
	 *

	 * XXX: Should we skip this on unclean_stop? */

	o2hb_prepare_block(reg, 0);

	ret = o2hb_issue_node_write(reg, &write_bio, &write_wc);

	ret = o2hb_issue_node_write(reg, &write_wc);

	if (ret == 0) {

		o2hb_wait_on_io(reg, &write_wc);

		bio_put(write_bio);

	} else {

		mlog_errno(ret);

	}

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