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rbd: support timeout in rbd_wait_state_locked()

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currently, the rbd_wait_state_locked() will wait forever if we
can't get our state locked. Example:

rbd map --exclusive test1  --> /dev/rbd0
rbd map test1  --> /dev/rbd1
dd if=/dev/zero of=/dev/rbd1 bs=1M count=1 --> IO blocked

To avoid this problem, this patch introduce a timeout design
in rbd_wait_state_locked(). Then rbd_wait_state_locked() will
return error when we reach a timeout.

This patch allow user to set the lock_timeout in rbd mapping.

Signed-off-by: Dongsheng Yang <dongsheng.yang@easystack.cn>
Reviewed-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
This commit is contained in:
Dongsheng Yang 2018-03-26 10:22:55 -04:00 committed by Ilya Dryomov
parent 2f18d46683
commit 34f55d0b3a
1 changed files with 21 additions and 1 deletions
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22
drivers/block/rbd.c
View file

@ -732,6 +732,7 @@ static struct rbd_client *rbd_client_find(struct ceph_options *ceph_opts)
*/
enum {
Opt_queue_depth,
Opt_lock_timeout,
Opt_last_int,
/* int args above */
Opt_last_string,
@ -745,6 +746,7 @@ enum {
static match_table_t rbd_opts_tokens = {
{Opt_queue_depth, "queue_depth=%d"},
{Opt_lock_timeout, "lock_timeout=%d"},
/* int args above */
/* string args above */
{Opt_read_only, "read_only"},
@ -758,12 +760,14 @@ static match_table_t rbd_opts_tokens = {
struct rbd_options {
int queue_depth;
unsigned long lock_timeout;
bool read_only;
bool lock_on_read;
bool exclusive;
};
#define RBD_QUEUE_DEPTH_DEFAULT BLKDEV_MAX_RQ
#define RBD_LOCK_TIMEOUT_DEFAULT 0 /* no timeout */
#define RBD_READ_ONLY_DEFAULT false
#define RBD_LOCK_ON_READ_DEFAULT false
#define RBD_EXCLUSIVE_DEFAULT false
@ -796,6 +800,14 @@ static int parse_rbd_opts_token(char *c, void *private)
}
rbd_opts->queue_depth = intval;
break;
case Opt_lock_timeout:
/* 0 is "wait forever" (i.e. infinite timeout) */
if (intval < 0 || intval > INT_MAX / 1000) {
pr_err("lock_timeout out of range\n");
return -EINVAL;
}
rbd_opts->lock_timeout = msecs_to_jiffies(intval * 1000);
break;
case Opt_read_only:
rbd_opts->read_only = true;
break;
@ -3536,6 +3548,7 @@ static int rbd_obj_method_sync(struct rbd_device *rbd_dev,
static int rbd_wait_state_locked(struct rbd_device *rbd_dev, bool may_acquire)
{
DEFINE_WAIT(wait);
unsigned long timeout;
int ret = 0;
if (test_bit(RBD_DEV_FLAG_BLACKLISTED, &rbd_dev->flags))
@ -3559,12 +3572,18 @@ static int rbd_wait_state_locked(struct rbd_device *rbd_dev, bool may_acquire)
prepare_to_wait_exclusive(&rbd_dev->lock_waitq, &wait,
TASK_UNINTERRUPTIBLE);
up_read(&rbd_dev->lock_rwsem);
schedule();
timeout = schedule_timeout(ceph_timeout_jiffies(
rbd_dev->opts->lock_timeout));
down_read(&rbd_dev->lock_rwsem);
if (test_bit(RBD_DEV_FLAG_BLACKLISTED, &rbd_dev->flags)) {
ret = -EBLACKLISTED;
break;
}
if (!timeout) {
rbd_warn(rbd_dev, "timed out waiting for lock");
ret = -ETIMEDOUT;
break;
}
} while (rbd_dev->lock_state != RBD_LOCK_STATE_LOCKED);
finish_wait(&rbd_dev->lock_waitq, &wait);
@ -5186,6 +5205,7 @@ static int rbd_add_parse_args(const char *buf,
rbd_opts->read_only = RBD_READ_ONLY_DEFAULT;
rbd_opts->queue_depth = RBD_QUEUE_DEPTH_DEFAULT;
rbd_opts->lock_timeout = RBD_LOCK_TIMEOUT_DEFAULT;
rbd_opts->lock_on_read = RBD_LOCK_ON_READ_DEFAULT;
rbd_opts->exclusive = RBD_EXCLUSIVE_DEFAULT;