From b559292e066f6d570cd5aa5dbd41de61dd04bdce Mon Sep 17 00:00:00 2001 From: Philipp Reisner Date: Thu, 11 Jan 2007 10:58:10 +0100 Subject: [PATCH] [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: Philipp Reisner Signed-off-by: Mark Fasheh --- fs/ocfs2/cluster/heartbeat.c | 158 +++++++---------------------------- 1 file changed, 31 insertions(+), 127 deletions(-) diff --git a/fs/ocfs2/cluster/heartbeat.c b/fs/ocfs2/cluster/heartbeat.c index 277ca67a2ad6..5a9779bb9236 100644 --- a/fs/ocfs2/cluster/heartbeat.c +++ b/fs/ocfs2/cluster/heartbeat.c @@ -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); + o2hb_bio_wait_init(&wc); - 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; - - /* 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, ¤t_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); }