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Commit ae00d4f3 authored by Sage Weil's avatar Sage Weil
Browse files

ceph: fix cap_snap and realm split 



The cap_snap creation/queueing relies on both the current i_head_snapc
_and_ the i_snap_realm pointers being correct, so that the new cap_snap
can properly reference the old context and the new i_head_snapc can be
updated to reference the new snaprealm's context.  To fix this, we:

 - move inodes completely to the new (split) realm so that i_snap_realm
   is correct, and
 - generate the new snapc's _before_ queueing the cap_snaps in
   ceph_update_snap_trace().

Signed-off-by: default avatarSage Weil <sage@newdream.net>
parent cfc0bf66

fs/ceph/addr.c

+2 −2
Original line number Diff line number Diff line
@@ -411,8 +411,8 @@ static int writepage_nounlock(struct page *page, struct writeback_control *wbc) 
	if (i_size < page_off + len)

		len = i_size - page_off;



	dout("writepage %p page %p index %lu on %llu~%u\n",

	     inode, page, page->index, page_off, len);

	dout("writepage %p page %p index %lu on %llu~%u snapc %p\n",

	     inode, page, page->index, page_off, len, snapc);



	writeback_stat = atomic_long_inc_return(&client->writeback_count);

	if (writeback_stat >

fs/ceph/snap.c

+29 −59
Original line number Diff line number Diff line
@@ -119,6 +119,7 @@ static struct ceph_snap_realm *ceph_create_snap_realm( 
	INIT_LIST_HEAD(&realm->children);

	INIT_LIST_HEAD(&realm->child_item);

	INIT_LIST_HEAD(&realm->empty_item);

	INIT_LIST_HEAD(&realm->dirty_item);

	INIT_LIST_HEAD(&realm->inodes_with_caps);

	spin_lock_init(&realm->inodes_with_caps_lock);

	__insert_snap_realm(&mdsc->snap_realms, realm);
@@ -604,6 +605,7 @@ int ceph_update_snap_trace(struct ceph_mds_client *mdsc, 
	struct ceph_snap_realm *realm;

	int invalidate = 0;

	int err = -ENOMEM;

	LIST_HEAD(dirty_realms);



	dout("update_snap_trace deletion=%d\n", deletion);

more:
@@ -626,24 +628,6 @@ int ceph_update_snap_trace(struct ceph_mds_client *mdsc, 
		}

	}



	if (le64_to_cpu(ri->seq) > realm->seq) {

		dout("update_snap_trace updating %llx %p %lld -> %lld\n",

		     realm->ino, realm, realm->seq, le64_to_cpu(ri->seq));

		/*

		 * if the realm seq has changed, queue a cap_snap for every

		 * inode with open caps.  we do this _before_ we update

		 * the realm info so that we prepare for writeback under the

		 * _previous_ snap context.

		 *

		 * ...unless it's a snap deletion!

		 */

		if (!deletion)

			queue_realm_cap_snaps(realm);

	} else {

		dout("update_snap_trace %llx %p seq %lld unchanged\n",

		     realm->ino, realm, realm->seq);

	}



	/* ensure the parent is correct */

	err = adjust_snap_realm_parent(mdsc, realm, le64_to_cpu(ri->parent));

	if (err < 0)
@@ -651,6 +635,8 @@ int ceph_update_snap_trace(struct ceph_mds_client *mdsc, 
	invalidate += err;



	if (le64_to_cpu(ri->seq) > realm->seq) {

		dout("update_snap_trace updating %llx %p %lld -> %lld\n",

		     realm->ino, realm, realm->seq, le64_to_cpu(ri->seq));

		/* update realm parameters, snap lists */

		realm->seq = le64_to_cpu(ri->seq);

		realm->created = le64_to_cpu(ri->created);
@@ -668,9 +654,17 @@ int ceph_update_snap_trace(struct ceph_mds_client *mdsc, 
		if (err < 0)

			goto fail;



		/* queue realm for cap_snap creation */

		list_add(&realm->dirty_item, &dirty_realms);



		invalidate = 1;

	} else if (!realm->cached_context) {

		dout("update_snap_trace %llx %p seq %lld new\n",

		     realm->ino, realm, realm->seq);

		invalidate = 1;

	} else {

		dout("update_snap_trace %llx %p seq %lld unchanged\n",

		     realm->ino, realm, realm->seq);

	}



	dout("done with %llx %p, invalidated=%d, %p %p\n", realm->ino,
@@ -683,6 +677,14 @@ int ceph_update_snap_trace(struct ceph_mds_client *mdsc, 
	if (invalidate)

		rebuild_snap_realms(realm);



	/*

	 * queue cap snaps _after_ we've built the new snap contexts,

	 * so that i_head_snapc can be set appropriately.

	 */

	list_for_each_entry(realm, &dirty_realms, dirty_item) {

		queue_realm_cap_snaps(realm);

	}



	__cleanup_empty_realms(mdsc);

	return 0;
@@ -816,6 +818,7 @@ void ceph_handle_snap(struct ceph_mds_client *mdsc, 
			};

			struct inode *inode = ceph_find_inode(sb, vino);

			struct ceph_inode_info *ci;

			struct ceph_snap_realm *oldrealm;



			if (!inode)

				continue;
@@ -841,18 +844,19 @@ void ceph_handle_snap(struct ceph_mds_client *mdsc, 
			dout(" will move %p to split realm %llx %p\n",

			     inode, realm->ino, realm);

			/*

			 * Remove the inode from the realm's inode

			 * list, but don't add it to the new realm

			 * yet.  We don't want the cap_snap to be

			 * queued (again) by ceph_update_snap_trace()

			 * below.  Queue it _now_, under the old context.

			 * Move the inode to the new realm

			 */

			spin_lock(&realm->inodes_with_caps_lock);

			list_del_init(&ci->i_snap_realm_item);

			list_add(&ci->i_snap_realm_item,

				 &realm->inodes_with_caps);

			oldrealm = ci->i_snap_realm;

			ci->i_snap_realm = realm;

			spin_unlock(&realm->inodes_with_caps_lock);

			spin_unlock(&inode->i_lock);



			ceph_queue_cap_snap(ci);

			ceph_get_snap_realm(mdsc, realm);

			ceph_put_snap_realm(mdsc, oldrealm);



			iput(inode);

			continue;
@@ -880,43 +884,9 @@ void ceph_handle_snap(struct ceph_mds_client *mdsc, 
	ceph_update_snap_trace(mdsc, p, e,

			       op == CEPH_SNAP_OP_DESTROY);



	if (op == CEPH_SNAP_OP_SPLIT) {

		/*

		 * ok, _now_ add the inodes into the new realm.

		 */

		for (i = 0; i < num_split_inos; i++) {

			struct ceph_vino vino = {

				.ino = le64_to_cpu(split_inos[i]),

				.snap = CEPH_NOSNAP,

			};

			struct inode *inode = ceph_find_inode(sb, vino);

			struct ceph_inode_info *ci;



			if (!inode)

				continue;

			ci = ceph_inode(inode);

			spin_lock(&inode->i_lock);

			if (list_empty(&ci->i_snap_realm_item)) {

				struct ceph_snap_realm *oldrealm =

					ci->i_snap_realm;



				dout(" moving %p to split realm %llx %p\n",

				     inode, realm->ino, realm);

				spin_lock(&realm->inodes_with_caps_lock);

				list_add(&ci->i_snap_realm_item,

					 &realm->inodes_with_caps);

				ci->i_snap_realm = realm;

				spin_unlock(&realm->inodes_with_caps_lock);

				ceph_get_snap_realm(mdsc, realm);

				ceph_put_snap_realm(mdsc, oldrealm);

			}

			spin_unlock(&inode->i_lock);

			iput(inode);

		}



	if (op == CEPH_SNAP_OP_SPLIT)

		/* we took a reference when we created the realm, above */

		ceph_put_snap_realm(mdsc, realm);

	}



	__cleanup_empty_realms(mdsc);

fs/ceph/super.h

+2 −0
Original line number Diff line number Diff line
@@ -690,6 +690,8 @@ struct ceph_snap_realm { 


	struct list_head empty_item;     /* if i have ref==0 */



	struct list_head dirty_item;     /* if realm needs new context */



	/* the current set of snaps for this realm */

	struct ceph_snap_context *cached_context;