mirrors/linux-stable
1
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git synced 2024-08-23 17:30:02 +00:00
Code Issues Releases Wiki Activity

md/raid10: simplify handle_read_error()

Browse source 
handle_read_error() duplicates a lot of the work that raid10_read_request()
does, so it makes sense to just use that function.

handle_read_error() relies on the same r10bio being re-used so that,
in the case of a read-only array, setting IO_BLOCKED in r1bio->devs[].bio
ensures read_balance() won't re-use that device.
So when called from raid10_make_request() we clear that array, but not
when called from handle_read_error().

Two parts of handle_read_error() that need to be preserved are the warning
message it prints, so they are conditionally added to
raid10_read_request().  If the failing rdev can be found, messages
are printed.  Otherwise they aren't.

Not that as rdev_dec_pending() has already been called on the failing
rdev, we need to use rcu_read_lock() to get a new reference from
the conf.  We only use this to get the name of the failing block device.

With this change, we no longer need inc_pending().

Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Shaohua Li <shli@fb.com>
This commit is contained in:
NeilBrown 2017-04-05 14:05:51 +10:00 committed by Shaohua Li
parent fc9977dd06
commit 545250f248
1 changed files with 47 additions and 75 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

122
drivers/md/raid10.c
View file

@ -1008,15 +1008,6 @@ static void wait_barrier(struct r10conf *conf)
spin_unlock_irq(&conf->resync_lock);
}
static void inc_pending(struct r10conf *conf)
{
/* The current request requires multiple r10_bio, so
* we need to increment the pending count.
*/
WARN_ON(!atomic_read(&conf->nr_pending));
atomic_inc(&conf->nr_pending);
}
static void allow_barrier(struct r10conf *conf)
{
if ((atomic_dec_and_test(&conf->nr_pending)) ||
@ -1130,8 +1121,38 @@ static void raid10_read_request(struct mddev *mddev, struct bio *bio,
int max_sectors;
sector_t sectors;
struct md_rdev *rdev;
int slot;
char b[BDEVNAME_SIZE];
int slot = r10_bio->read_slot;
struct md_rdev *err_rdev = NULL;
gfp_t gfp = GFP_NOIO;
if (r10_bio->devs[slot].rdev) {
/*
* This is an error retry, but we cannot
* safely dereference the rdev in the r10_bio,
* we must use the one in conf.
* If it has already been disconnected (unlikely)
* we lose the device name in error messages.
*/
int disk;
/*
* As we are blocking raid10, it is a little safer to
* use __GFP_HIGH.
*/
gfp = GFP_NOIO | __GFP_HIGH;
rcu_read_lock();
disk = r10_bio->devs[slot].devnum;
err_rdev = rcu_dereference(conf->mirrors[disk].rdev);
if (err_rdev)
bdevname(err_rdev->bdev, b);
else {
strcpy(b, "???");
/* This never gets dereferenced */
err_rdev = r10_bio->devs[slot].rdev;
}
rcu_read_unlock();
}
/*
* Register the new request and wait if the reconstruction
* thread has put up a bar for new requests.
@ -1158,12 +1179,22 @@ static void raid10_read_request(struct mddev *mddev, struct bio *bio,
rdev = read_balance(conf, r10_bio, &max_sectors);
if (!rdev) {
if (err_rdev) {
pr_crit_ratelimited("md/raid10:%s: %s: unrecoverable I/O read error for block %llu\n",
mdname(mddev), b,
(unsigned long long)r10_bio->sector);
}
raid_end_bio_io(r10_bio);
return;
}
if (err_rdev)
pr_err_ratelimited("md/raid10:%s: %s: redirecting sector %llu to another mirror\n",
mdname(mddev),
bdevname(rdev->bdev, b),
(unsigned long long)r10_bio->sector);
if (max_sectors < bio_sectors(bio)) {
struct bio *split = bio_split(bio, max_sectors,
GFP_NOIO, conf->bio_split);
gfp, conf->bio_split);
bio_chain(split, bio);
generic_make_request(bio);
bio = split;
@ -1172,7 +1203,7 @@ static void raid10_read_request(struct mddev *mddev, struct bio *bio,
}
slot = r10_bio->read_slot;
read_bio = bio_clone_fast(bio, GFP_NOIO, mddev->bio_set);
read_bio = bio_clone_fast(bio, gfp, mddev->bio_set);
r10_bio->devs[slot].bio = read_bio;
r10_bio->devs[slot].rdev = rdev;
@ -1487,6 +1518,7 @@ static void __make_request(struct mddev *mddev, struct bio *bio, int sectors)
r10_bio->mddev = mddev;
r10_bio->sector = bio->bi_iter.bi_sector;
r10_bio->state = 0;
memset(r10_bio->devs, 0, sizeof(r10_bio->devs[0]) * conf->copies);
if (bio_data_dir(bio) == READ)
raid10_read_request(mddev, bio, r10_bio);
@ -2556,9 +2588,6 @@ static void handle_read_error(struct mddev *mddev, struct r10bio *r10_bio)
struct bio *bio;
struct r10conf *conf = mddev->private;
struct md_rdev *rdev = r10_bio->devs[slot].rdev;
char b[BDEVNAME_SIZE];
unsigned long do_sync;
int max_sectors;
dev_t bio_dev;
sector_t bio_last_sector;
@ -2571,7 +2600,6 @@ static void handle_read_error(struct mddev *mddev, struct r10bio *r10_bio)
* frozen.
*/
bio = r10_bio->devs[slot].bio;
bdevname(bio->bi_bdev, b);
bio_dev = bio->bi_bdev->bd_dev;
bio_last_sector = r10_bio->devs[slot].addr + rdev->data_offset + r10_bio->sectors;
bio_put(bio);
@ -2587,65 +2615,9 @@ static void handle_read_error(struct mddev *mddev, struct r10bio *r10_bio)
md_error(mddev, rdev);
rdev_dec_pending(rdev, mddev);
read_more:
rdev = read_balance(conf, r10_bio, &max_sectors);
if (rdev == NULL) {
pr_crit_ratelimited("md/raid10:%s: %s: unrecoverable I/O read error for block %llu\n",
mdname(mddev), b,
(unsigned long long)r10_bio->sector);
raid_end_bio_io(r10_bio);
return;
}
do_sync = (r10_bio->master_bio->bi_opf & REQ_SYNC);
slot = r10_bio->read_slot;
pr_err_ratelimited("md/raid10:%s: %s: redirecting sector %llu to another mirror\n",
mdname(mddev),
bdevname(rdev->bdev, b),
(unsigned long long)r10_bio->sector);
bio = bio_clone_fast(r10_bio->master_bio, GFP_NOIO, mddev->bio_set);
bio_trim(bio, r10_bio->sector - bio->bi_iter.bi_sector, max_sectors);
r10_bio->devs[slot].bio = bio;
r10_bio->devs[slot].rdev = rdev;
bio->bi_iter.bi_sector = r10_bio->devs[slot].addr
+ choose_data_offset(r10_bio, rdev);
bio->bi_bdev = rdev->bdev;
bio_set_op_attrs(bio, REQ_OP_READ, do_sync);
if (test_bit(FailFast, &rdev->flags) &&
test_bit(R10BIO_FailFast, &r10_bio->state))
bio->bi_opf |= MD_FAILFAST;
bio->bi_private = r10_bio;
bio->bi_end_io = raid10_end_read_request;
trace_block_bio_remap(bdev_get_queue(bio->bi_bdev),
bio, bio_dev,
bio_last_sector - r10_bio->sectors);
if (max_sectors < r10_bio->sectors) {
/* Drat - have to split this up more */
struct bio *mbio = r10_bio->master_bio;
int sectors_handled =
r10_bio->sector + max_sectors
- mbio->bi_iter.bi_sector;
r10_bio->sectors = max_sectors;
bio_inc_remaining(mbio);
inc_pending(conf);
generic_make_request(bio);
r10_bio = mempool_alloc(conf->r10bio_pool,
GFP_NOIO);
r10_bio->master_bio = mbio;
r10_bio->sectors = bio_sectors(mbio) - sectors_handled;
r10_bio->state = 0;
set_bit(R10BIO_ReadError,
&r10_bio->state);
r10_bio->mddev = mddev;
r10_bio->sector = mbio->bi_iter.bi_sector
+ sectors_handled;
goto read_more;
} else
generic_make_request(bio);
allow_barrier(conf);
r10_bio->state = 0;
raid10_read_request(mddev, r10_bio->master_bio, r10_bio);
}
static void handle_write_completed(struct r10conf *conf, struct r10bio *r10_bio)