Commit b5bc8e08 authored by Lars Ellenberg's avatar Lars Ellenberg Committed by Jens Axboe

drbd: split drbd_al_begin_io into fastpath, prepare, and commit

Signed-off-by: default avatarPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: default avatarLars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 113fef9e
......@@ -104,7 +104,6 @@ struct update_al_work {
int err;
};
static int al_write_transaction(struct drbd_conf *mdev, bool delegate);
void *drbd_md_get_buffer(struct drbd_conf *mdev)
{
......@@ -246,30 +245,37 @@ static struct lc_element *_al_get(struct drbd_conf *mdev, unsigned int enr)
return al_ext;
}
/*
* @delegate: delegate activity log I/O to the worker thread
*/
void drbd_al_begin_io(struct drbd_conf *mdev, struct drbd_interval *i, bool delegate)
bool drbd_al_begin_io_fastpath(struct drbd_conf *mdev, struct drbd_interval *i)
{
/* for bios crossing activity log extent boundaries,
* we may need to activate two extents in one go */
unsigned first = i->sector >> (AL_EXTENT_SHIFT-9);
unsigned last = i->size == 0 ? first : (i->sector + (i->size >> 9) - 1) >> (AL_EXTENT_SHIFT-9);
unsigned enr;
bool need_transaction = false;
bool locked = false;
bool fastpath_ok = true;
/* When called through generic_make_request(), we must delegate
* activity log I/O to the worker thread: a further request
* submitted via generic_make_request() within the same task
* would be queued on current->bio_list, and would only start
* after this function returns (see generic_make_request()).
*
* However, if we *are* the worker, we must not delegate to ourselves.
*/
D_ASSERT((unsigned)(last - first) <= 1);
D_ASSERT(atomic_read(&mdev->local_cnt) > 0);
if (delegate)
BUG_ON(current == mdev->tconn->worker.task);
/* FIXME figure out a fast path for bios crossing AL extent boundaries */
if (first != last)
return false;
spin_lock_irq(&mdev->al_lock);
fastpath_ok =
lc_find(mdev->resync, first/AL_EXT_PER_BM_SECT) == NULL &&
lc_try_get(mdev->act_log, first) != NULL;
spin_unlock_irq(&mdev->al_lock);
return fastpath_ok;
}
bool drbd_al_begin_io_prepare(struct drbd_conf *mdev, struct drbd_interval *i)
{
/* for bios crossing activity log extent boundaries,
* we may need to activate two extents in one go */
unsigned first = i->sector >> (AL_EXTENT_SHIFT-9);
unsigned last = i->size == 0 ? first : (i->sector + (i->size >> 9) - 1) >> (AL_EXTENT_SHIFT-9);
unsigned enr;
bool need_transaction = false;
D_ASSERT(first <= last);
D_ASSERT(atomic_read(&mdev->local_cnt) > 0);
......@@ -280,11 +286,28 @@ void drbd_al_begin_io(struct drbd_conf *mdev, struct drbd_interval *i, bool dele
if (al_ext->lc_number != enr)
need_transaction = true;
}
return need_transaction;
}
/* If *this* request was to an already active extent,
* we're done, even if there are pending changes. */
if (!need_transaction)
return;
static int al_write_transaction(struct drbd_conf *mdev, bool delegate);
/* When called through generic_make_request(), we must delegate
* activity log I/O to the worker thread: a further request
* submitted via generic_make_request() within the same task
* would be queued on current->bio_list, and would only start
* after this function returns (see generic_make_request()).
*
* However, if we *are* the worker, we must not delegate to ourselves.
*/
/*
* @delegate: delegate activity log I/O to the worker thread
*/
void drbd_al_begin_io_commit(struct drbd_conf *mdev, bool delegate)
{
bool locked = false;
BUG_ON(delegate && current == mdev->tconn->worker.task);
/* Serialize multiple transactions.
* This uses test_and_set_bit, memory barrier is implicit.
......@@ -303,11 +326,8 @@ void drbd_al_begin_io(struct drbd_conf *mdev, struct drbd_interval *i, bool dele
write_al_updates = rcu_dereference(mdev->ldev->disk_conf)->al_updates;
rcu_read_unlock();
if (write_al_updates) {
if (write_al_updates)
al_write_transaction(mdev, delegate);
mdev->al_writ_cnt++;
}
spin_lock_irq(&mdev->al_lock);
/* FIXME
if (err)
......@@ -321,6 +341,17 @@ void drbd_al_begin_io(struct drbd_conf *mdev, struct drbd_interval *i, bool dele
}
}
/*
* @delegate: delegate activity log I/O to the worker thread
*/
void drbd_al_begin_io(struct drbd_conf *mdev, struct drbd_interval *i, bool delegate)
{
BUG_ON(delegate && current == mdev->tconn->worker.task);
if (drbd_al_begin_io_prepare(mdev, i))
drbd_al_begin_io_commit(mdev, delegate);
}
void drbd_al_complete_io(struct drbd_conf *mdev, struct drbd_interval *i)
{
/* for bios crossing activity log extent boundaries,
......@@ -478,15 +509,22 @@ _al_write_transaction(struct drbd_conf *mdev)
crc = crc32c(0, buffer, 4096);
buffer->crc32c = cpu_to_be32(crc);
/* normal execution path goes through all three branches */
if (drbd_bm_write_hinted(mdev))
err = -EIO;
/* drbd_chk_io_error done already */
else if (drbd_md_sync_page_io(mdev, mdev->ldev, sector, WRITE)) {
else {
bool write_al_updates;
rcu_read_lock();
write_al_updates = rcu_dereference(mdev->ldev->disk_conf)->al_updates;
rcu_read_unlock();
if (write_al_updates) {
if (drbd_md_sync_page_io(mdev, mdev->ldev, sector, WRITE)) {
err = -EIO;
drbd_chk_io_error(mdev, 1, DRBD_META_IO_ERROR);
} else {
mdev->al_tr_number++;
mdev->al_writ_cnt++;
}
}
}
drbd_md_put_buffer(mdev);
......
......@@ -1611,6 +1611,7 @@ extern const char *drbd_conn_str(enum drbd_conns s);
extern const char *drbd_role_str(enum drbd_role s);
/* drbd_actlog.c */
extern bool drbd_al_begin_io_fastpath(struct drbd_conf *mdev, struct drbd_interval *i);
extern void drbd_al_begin_io(struct drbd_conf *mdev, struct drbd_interval *i, bool delegate);
extern void drbd_al_complete_io(struct drbd_conf *mdev, struct drbd_interval *i);
extern void drbd_rs_complete_io(struct drbd_conf *mdev, sector_t sector);
......
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