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drbd: RCU for rs_plan_s 

This removes the issue with using peer_seq_lock out of different
contexts.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
This commit is contained in:
Philipp Reisner 2011-05-03 16:47:02 +02:00
parent d589a21e5d
commit 813472ced7
4 changed files with 77 additions and 55 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
drivers/block/drbd/drbd_int.h
View File

@ -998,7 +998,7 @@ struct drbd_conf {
int rs_last_events; /* counter of read or write "events" (unit sectors)
* on the lower level device when we last looked. */
int c_sync_rate; /* current resync rate after syncer throttle magic */
struct fifo_buffer *rs_plan_s; /* correction values of resync planer */
struct fifo_buffer *rs_plan_s; /* correction values of resync planer (RCU, tconn->conn_update) */
int rs_in_flight; /* resync sectors in flight (to proxy, in proxy and from proxy) */
atomic_t ap_in_flight; /* App sectors in flight (waiting for ack) */
int peer_max_bio_size;

18
drivers/block/drbd/drbd_nl.c
View File

@ -1115,7 +1115,7 @@ int drbd_adm_disk_opts(struct sk_buff *skb, struct genl_info *info)
enum drbd_ret_code retcode;
struct drbd_conf *mdev;
struct disk_conf *new_disk_conf, *old_disk_conf;
struct fifo_buffer *rs_plan_s = NULL;
struct fifo_buffer *old_plan = NULL, *new_plan = NULL;
int err, fifo_size;
retcode = drbd_adm_prepare(skb, info, DRBD_ADM_NEED_MINOR);
@ -1158,8 +1158,8 @@ int drbd_adm_disk_opts(struct sk_buff *skb, struct genl_info *info)
fifo_size = (new_disk_conf->c_plan_ahead * 10 * SLEEP_TIME) / HZ;
if (fifo_size != mdev->rs_plan_s->size) {
rs_plan_s = fifo_alloc(fifo_size);
if (!rs_plan_s) {
new_plan = fifo_alloc(fifo_size);
if (!new_plan) {
dev_err(DEV, "kmalloc of fifo_buffer failed");
retcode = ERR_NOMEM;
goto fail_unlock;
@ -1188,13 +1188,10 @@ int drbd_adm_disk_opts(struct sk_buff *skb, struct genl_info *info)
if (retcode != NO_ERROR)
goto fail_unlock;
spin_lock(&mdev->peer_seq_lock);
if (rs_plan_s) {
kfree(mdev->rs_plan_s);
mdev->rs_plan_s = rs_plan_s;
rs_plan_s = NULL;
if (new_plan) {
old_plan = mdev->rs_plan_s;
rcu_assign_pointer(mdev->rs_plan_s, new_plan);
}
spin_unlock(&mdev->peer_seq_lock);
drbd_md_sync(mdev);
@ -1204,13 +1201,14 @@ int drbd_adm_disk_opts(struct sk_buff *skb, struct genl_info *info)
mutex_unlock(&mdev->tconn->conf_update);
synchronize_rcu();
kfree(old_disk_conf);
kfree(old_plan);
goto success;
fail_unlock:
mutex_unlock(&mdev->tconn->conf_update);
fail:
kfree(new_disk_conf);
kfree(rs_plan_s);
kfree(new_plan);
success:
put_ldev(mdev);
out:

71
drivers/block/drbd/drbd_receiver.c
View File

@ -3157,9 +3157,9 @@ static int receive_SyncParam(struct drbd_tconn *tconn, struct packet_info *pi)
struct crypto_hash *verify_tfm = NULL;
struct crypto_hash *csums_tfm = NULL;
struct net_conf *old_net_conf, *new_net_conf = NULL;
struct disk_conf *old_disk_conf, *new_disk_conf = NULL;
struct disk_conf *old_disk_conf = NULL, *new_disk_conf = NULL;
const int apv = tconn->agreed_pro_version;
struct fifo_buffer *rs_plan_s = NULL;
struct fifo_buffer *old_plan = NULL, *new_plan = NULL;
int fifo_size = 0;
int err;
@ -3200,18 +3200,22 @@ static int receive_SyncParam(struct drbd_tconn *tconn, struct packet_info *pi)
if (err)
return err;
new_disk_conf = kzalloc(sizeof(struct disk_conf), GFP_KERNEL);
if (!new_disk_conf) {
dev_err(DEV, "Allocation of new disk_conf failed\n");
return -ENOMEM;
}
mutex_lock(&mdev->tconn->conf_update);
old_net_conf = mdev->tconn->net_conf;
old_disk_conf = mdev->ldev->disk_conf;
*new_disk_conf = *old_disk_conf;
if (get_ldev(mdev)) {
new_disk_conf = kzalloc(sizeof(struct disk_conf), GFP_KERNEL);
if (!new_disk_conf) {
put_ldev(mdev);
mutex_unlock(&mdev->tconn->conf_update);
dev_err(DEV, "Allocation of new disk_conf failed\n");
return -ENOMEM;
}
new_disk_conf->resync_rate = be32_to_cpu(p->rate);
old_disk_conf = mdev->ldev->disk_conf;
*new_disk_conf = *old_disk_conf;
new_disk_conf->resync_rate = be32_to_cpu(p->rate);
}
if (apv >= 88) {
if (apv == 88) {
@ -3219,15 +3223,13 @@ static int receive_SyncParam(struct drbd_tconn *tconn, struct packet_info *pi)
dev_err(DEV, "verify-alg too long, "
"peer wants %u, accepting only %u byte\n",
data_size, SHARED_SECRET_MAX);
mutex_unlock(&mdev->tconn->conf_update);
return -EIO;
err = -EIO;
goto reconnect;
}
err = drbd_recv_all(mdev->tconn, p->verify_alg, data_size);
if (err) {
mutex_unlock(&mdev->tconn->conf_update);
return err;
}
if (err)
goto reconnect;
/* we expect NUL terminated string */
/* but just in case someone tries to be evil */
D_ASSERT(p->verify_alg[data_size-1] == 0);
@ -3270,7 +3272,7 @@ static int receive_SyncParam(struct drbd_tconn *tconn, struct packet_info *pi)
}
}
if (apv > 94) {
if (apv > 94 && new_disk_conf) {
new_disk_conf->c_plan_ahead = be32_to_cpu(p->c_plan_ahead);
new_disk_conf->c_delay_target = be32_to_cpu(p->c_delay_target);
new_disk_conf->c_fill_target = be32_to_cpu(p->c_fill_target);
@ -3278,8 +3280,8 @@ static int receive_SyncParam(struct drbd_tconn *tconn, struct packet_info *pi)
fifo_size = (new_disk_conf->c_plan_ahead * 10 * SLEEP_TIME) / HZ;
if (fifo_size != mdev->rs_plan_s->size) {
rs_plan_s = fifo_alloc(fifo_size);
if (!rs_plan_s) {
new_plan = fifo_alloc(fifo_size);
if (!new_plan) {
dev_err(DEV, "kmalloc of fifo_buffer failed");
put_ldev(mdev);
goto disconnect;
@ -3314,24 +3316,39 @@ static int receive_SyncParam(struct drbd_tconn *tconn, struct packet_info *pi)
}
}
rcu_assign_pointer(mdev->ldev->disk_conf, new_disk_conf);
spin_lock(&mdev->peer_seq_lock);
if (rs_plan_s) {
kfree(mdev->rs_plan_s);
mdev->rs_plan_s = rs_plan_s;
if (new_disk_conf) {
rcu_assign_pointer(mdev->ldev->disk_conf, new_disk_conf);
put_ldev(mdev);
}
if (new_plan) {
old_plan = mdev->rs_plan_s;
rcu_assign_pointer(mdev->rs_plan_s, new_plan);
}
spin_unlock(&mdev->peer_seq_lock);
mutex_unlock(&mdev->tconn->conf_update);
synchronize_rcu();
if (new_net_conf)
kfree(old_net_conf);
kfree(old_disk_conf);
kfree(old_plan);
return 0;
reconnect:
if (new_disk_conf) {
put_ldev(mdev);
kfree(new_disk_conf);
}
mutex_unlock(&mdev->tconn->conf_update);
return -EIO;
disconnect:
kfree(rs_plan_s);
kfree(new_plan);
if (new_disk_conf) {
put_ldev(mdev);
kfree(new_disk_conf);
}
mutex_unlock(&mdev->tconn->conf_update);
/* just for completeness: actually not needed,
* as this is not reached if csums_tfm was ok. */

41
drivers/block/drbd/drbd_worker.c
View File

@ -460,15 +460,15 @@ static int drbd_rs_controller(struct drbd_conf *mdev)
int steps; /* Number of time steps to plan ahead */
int curr_corr;
int max_sect;
struct fifo_buffer *plan;
sect_in = atomic_xchg(&mdev->rs_sect_in, 0); /* Number of sectors that came in */
mdev->rs_in_flight -= sect_in;
spin_lock(&mdev->peer_seq_lock); /* get an atomic view on mdev->rs_plan_s */
rcu_read_lock();
dc = rcu_dereference(mdev->ldev->disk_conf);
plan = rcu_dereference(mdev->rs_plan_s);
steps = mdev->rs_plan_s->size; /* (dc->c_plan_ahead * 10 * SLEEP_TIME) / HZ; */
steps = plan->size; /* (dc->c_plan_ahead * 10 * SLEEP_TIME) / HZ; */
if (mdev->rs_in_flight + sect_in == 0) { /* At start of resync */
want = ((dc->resync_rate * 2 * SLEEP_TIME) / HZ) * steps;
@ -477,16 +477,16 @@ static int drbd_rs_controller(struct drbd_conf *mdev)
sect_in * dc->c_delay_target * HZ / (SLEEP_TIME * 10);
}
correction = want - mdev->rs_in_flight - mdev->rs_plan_s->total;
correction = want - mdev->rs_in_flight - plan->total;
/* Plan ahead */
cps = correction / steps;
fifo_add_val(mdev->rs_plan_s, cps);
mdev->rs_plan_s->total += cps * steps;
fifo_add_val(plan, cps);
plan->total += cps * steps;
/* What we do in this step */
curr_corr = fifo_push(mdev->rs_plan_s, 0);
mdev->rs_plan_s->total -= curr_corr;
curr_corr = fifo_push(plan, 0);
plan->total -= curr_corr;
req_sect = sect_in + curr_corr;
if (req_sect < 0)
@ -501,8 +501,6 @@ static int drbd_rs_controller(struct drbd_conf *mdev)
sect_in, mdev->rs_in_flight, want, correction,
steps, cps, mdev->rs_planed, curr_corr, req_sect);
*/
rcu_read_unlock();
spin_unlock(&mdev->peer_seq_lock);
return req_sect;
}
@ -510,15 +508,16 @@ static int drbd_rs_controller(struct drbd_conf *mdev)
static int drbd_rs_number_requests(struct drbd_conf *mdev)
{
int number;
if (mdev->rs_plan_s->size) { /* rcu_dereference(mdev->ldev->disk_conf)->c_plan_ahead */
rcu_read_lock();
if (rcu_dereference(mdev->rs_plan_s)->size) {
number = drbd_rs_controller(mdev) >> (BM_BLOCK_SHIFT - 9);
mdev->c_sync_rate = number * HZ * (BM_BLOCK_SIZE / 1024) / SLEEP_TIME;
} else {
rcu_read_lock();
mdev->c_sync_rate = rcu_dereference(mdev->ldev->disk_conf)->resync_rate;
rcu_read_unlock();
number = SLEEP_TIME * mdev->c_sync_rate / ((BM_BLOCK_SIZE / 1024) * HZ);
}
rcu_read_unlock();
/* ignore the amount of pending requests, the resync controller should
* throttle down to incoming reply rate soon enough anyways. */
@ -1468,13 +1467,21 @@ void drbd_sync_after_changed(struct drbd_conf *mdev)
void drbd_rs_controller_reset(struct drbd_conf *mdev)
{
struct fifo_buffer *plan;
atomic_set(&mdev->rs_sect_in, 0);
atomic_set(&mdev->rs_sect_ev, 0);
mdev->rs_in_flight = 0;
mdev->rs_plan_s->total = 0;
spin_lock(&mdev->peer_seq_lock);
fifo_set(mdev->rs_plan_s, 0);
spin_unlock(&mdev->peer_seq_lock);
/* Updating the RCU protected object in place is necessary since
this function gets called from atomic context.
It is valid since all other updates also lead to an completely
empty fifo */
rcu_read_lock();
plan = rcu_dereference(mdev->rs_plan_s);
plan->total = 0;
fifo_set(plan, 0);
rcu_read_unlock();
}
void start_resync_timer_fn(unsigned long data)