Skip to content

Commit

Permalink
[PATCH] ocfs2 heartbeat: clean up bio submission code
Browse files Browse the repository at this point in the history 
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 <philipp.reisner@linbit.com>
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
  • Loading branch information
Philipp Reisner authored and Mark Fasheh committed Feb 7, 2007
1 parent 925037b commit b559292
Showing 1 changed file with 31 additions and 127 deletions.
158 changes: 31 additions & 127 deletions fs/ocfs2/cluster/heartbeat.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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;
}
Expand All @@ -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);
}
Expand All @@ -231,168 +231,84 @@ static int o2hb_bio_end_io(struct bio *bio,
return 1;

o2hb_bio_wait_dec(wc, 1);
bio_put(bio);
return 0;
}

/* Setup a Bio to cover I/O against num_slots slots starting at
* 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);
goto bail;
}

/* 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, &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);
}

Expand All @@ -403,38 +319,30 @@ static int o2hb_read_slots(struct o2hb_region *reg,
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;
Expand Down Expand Up @@ -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,
Expand Down Expand Up @@ -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;
Expand All @@ -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
Expand Down Expand Up @@ -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;
Expand Down Expand Up @@ -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);
}
Expand Down

0 comments on commit b559292

Please sign in to comment.