Commit 3a03c67d authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'ceph-for-5.14-rc6' of git://github.com/ceph/ceph-client 

Pull ceph fixes from Ilya Dryomov:
 "A patch to avoid a soft lockup in ceph_check_delayed_caps() from Luis
  and a reference handling fix from Jeff that should address some memory
  corruption reports in the snaprealm area.

  Both marked for stable"

* tag 'ceph-for-5.14-rc6' of git://github.com/ceph/ceph-client:
  ceph: take snap_empty_lock atomically with snaprealm refcount change
  ceph: reduce contention in ceph_check_delayed_caps()
parents 82cce5f4 8434ffe7

fs/ceph/caps.c

+16 −1
Original line number Diff line number Diff line
@@ -4150,11 +4150,19 @@ void ceph_handle_caps(struct ceph_mds_session *session, 


/*

 * Delayed work handler to process end of delayed cap release LRU list.

 *

 * If new caps are added to the list while processing it, these won't get

 * processed in this run.  In this case, the ci->i_hold_caps_max will be

 * returned so that the work can be scheduled accordingly.

 */

void ceph_check_delayed_caps(struct ceph_mds_client *mdsc)

unsigned long ceph_check_delayed_caps(struct ceph_mds_client *mdsc)

{

	struct inode *inode;

	struct ceph_inode_info *ci;

	struct ceph_mount_options *opt = mdsc->fsc->mount_options;

	unsigned long delay_max = opt->caps_wanted_delay_max * HZ;

	unsigned long loop_start = jiffies;

	unsigned long delay = 0;



	dout("check_delayed_caps\n");

	spin_lock(&mdsc->cap_delay_lock);
@@ -4162,6 +4170,11 @@ void ceph_check_delayed_caps(struct ceph_mds_client *mdsc) 
		ci = list_first_entry(&mdsc->cap_delay_list,

				      struct ceph_inode_info,

				      i_cap_delay_list);

		if (time_before(loop_start, ci->i_hold_caps_max - delay_max)) {

			dout("%s caps added recently.  Exiting loop", __func__);

			delay = ci->i_hold_caps_max;

			break;

		}

		if ((ci->i_ceph_flags & CEPH_I_FLUSH) == 0 &&

		    time_before(jiffies, ci->i_hold_caps_max))

			break;
@@ -4177,6 +4190,8 @@ void ceph_check_delayed_caps(struct ceph_mds_client *mdsc) 
		}

	}

	spin_unlock(&mdsc->cap_delay_lock);



	return delay;

}



/*

fs/ceph/mds_client.c

+16 −9
Original line number Diff line number Diff line
@@ -4490,22 +4490,29 @@ void inc_session_sequence(struct ceph_mds_session *s) 
}



/*

 * delayed work -- periodically trim expired leases, renew caps with mds

 * delayed work -- periodically trim expired leases, renew caps with mds.  If

 * the @delay parameter is set to 0 or if it's more than 5 secs, the default

 * workqueue delay value of 5 secs will be used.

 */

static void schedule_delayed(struct ceph_mds_client *mdsc)

static void schedule_delayed(struct ceph_mds_client *mdsc, unsigned long delay)

{

	int delay = 5;

	unsigned hz = round_jiffies_relative(HZ * delay);

	schedule_delayed_work(&mdsc->delayed_work, hz);

	unsigned long max_delay = HZ * 5;



	/* 5 secs default delay */

	if (!delay || (delay > max_delay))

		delay = max_delay;

	schedule_delayed_work(&mdsc->delayed_work,

			      round_jiffies_relative(delay));

}



static void delayed_work(struct work_struct *work)

{

	int i;

	struct ceph_mds_client *mdsc =

		container_of(work, struct ceph_mds_client, delayed_work.work);

	unsigned long delay;

	int renew_interval;

	int renew_caps;

	int i;



	dout("mdsc delayed_work\n");
@@ -4545,7 +4552,7 @@ static void delayed_work(struct work_struct *work) 
	}

	mutex_unlock(&mdsc->mutex);



	ceph_check_delayed_caps(mdsc);

	delay = ceph_check_delayed_caps(mdsc);



	ceph_queue_cap_reclaim_work(mdsc);
@@ -4553,7 +4560,7 @@ static void delayed_work(struct work_struct *work) 


	maybe_recover_session(mdsc);



	schedule_delayed(mdsc);

	schedule_delayed(mdsc, delay);

}



int ceph_mdsc_init(struct ceph_fs_client *fsc)
@@ -5030,7 +5037,7 @@ void ceph_mdsc_handle_mdsmap(struct ceph_mds_client *mdsc, struct ceph_msg *msg) 
			  mdsc->mdsmap->m_epoch);



	mutex_unlock(&mdsc->mutex);

	schedule_delayed(mdsc);

	schedule_delayed(mdsc, 0);

	return;



bad_unlock:

fs/ceph/snap.c

+17 −17
Original line number Diff line number Diff line
@@ -67,20 +67,20 @@ void ceph_get_snap_realm(struct ceph_mds_client *mdsc, 
{

	lockdep_assert_held(&mdsc->snap_rwsem);



	dout("get_realm %p %d -> %d\n", realm,

	     atomic_read(&realm->nref), atomic_read(&realm->nref)+1);

	/*

	 * since we _only_ increment realm refs or empty the empty

	 * list with snap_rwsem held, adjusting the empty list here is

	 * safe.  we do need to protect against concurrent empty list

	 * additions, however.

	 * The 0->1 and 1->0 transitions must take the snap_empty_lock

	 * atomically with the refcount change. Go ahead and bump the

	 * nref here, unless it's 0, in which case we take the spinlock

	 * and then do the increment and remove it from the list.

	 */

	if (atomic_inc_return(&realm->nref) == 1) {

	if (atomic_inc_not_zero(&realm->nref))

		return;



	spin_lock(&mdsc->snap_empty_lock);

	if (atomic_inc_return(&realm->nref) == 1)

		list_del_init(&realm->empty_item);

	spin_unlock(&mdsc->snap_empty_lock);

}

}



static void __insert_snap_realm(struct rb_root *root,

				struct ceph_snap_realm *new)
@@ -208,28 +208,28 @@ static void __put_snap_realm(struct ceph_mds_client *mdsc, 
{

	lockdep_assert_held_write(&mdsc->snap_rwsem);



	dout("__put_snap_realm %llx %p %d -> %d\n", realm->ino, realm,

	     atomic_read(&realm->nref), atomic_read(&realm->nref)-1);

	/*

	 * We do not require the snap_empty_lock here, as any caller that

	 * increments the value must hold the snap_rwsem.

	 */

	if (atomic_dec_and_test(&realm->nref))

		__destroy_snap_realm(mdsc, realm);

}



/*

 * caller needn't hold any locks

 * See comments in ceph_get_snap_realm. Caller needn't hold any locks.

 */

void ceph_put_snap_realm(struct ceph_mds_client *mdsc,

			 struct ceph_snap_realm *realm)

{

	dout("put_snap_realm %llx %p %d -> %d\n", realm->ino, realm,

	     atomic_read(&realm->nref), atomic_read(&realm->nref)-1);

	if (!atomic_dec_and_test(&realm->nref))

	if (!atomic_dec_and_lock(&realm->nref, &mdsc->snap_empty_lock))

		return;



	if (down_write_trylock(&mdsc->snap_rwsem)) {

		spin_unlock(&mdsc->snap_empty_lock);

		__destroy_snap_realm(mdsc, realm);

		up_write(&mdsc->snap_rwsem);

	} else {

		spin_lock(&mdsc->snap_empty_lock);

		list_add(&realm->empty_item, &mdsc->snap_empty);

		spin_unlock(&mdsc->snap_empty_lock);

	}

fs/ceph/super.h

+1 −1
Original line number Diff line number Diff line
@@ -1167,7 +1167,7 @@ extern void ceph_flush_snaps(struct ceph_inode_info *ci, 
extern bool __ceph_should_report_size(struct ceph_inode_info *ci);

extern void ceph_check_caps(struct ceph_inode_info *ci, int flags,

			    struct ceph_mds_session *session);

extern void ceph_check_delayed_caps(struct ceph_mds_client *mdsc);

extern unsigned long ceph_check_delayed_caps(struct ceph_mds_client *mdsc);

extern void ceph_flush_dirty_caps(struct ceph_mds_client *mdsc);

extern int  ceph_drop_caps_for_unlink(struct inode *inode);

extern int ceph_encode_inode_release(void **p, struct inode *inode,