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Commit 3ae0bebc authored by Yan, Zheng's avatar Yan, Zheng Committed by Ilya Dryomov
Browse files

ceph: queue cap snap only when snap realm's context changes 



If we create capsnap when snap realm's context does not change, the
new capsnap's snapc is equal to ci->i_head_snapc. Page writeback code
can't differentiates dirty pages associated with the new capsnap from
dirty pages associated with i_head_snapc.

Signed-off-by: default avatar"Yan, Zheng" <zyan@redhat.com>
Signed-off-by: default avatarIlya Dryomov <idryomov@gmail.com>
parent c8fd0d37

fs/ceph/snap.c

+16 −21
Original line number Diff line number Diff line
@@ -299,7 +299,8 @@ static int cmpu64_rev(const void *a, const void *b) 
/*

 * build the snap context for a given realm.

 */

static int build_snap_context(struct ceph_snap_realm *realm)

static int build_snap_context(struct ceph_snap_realm *realm,

			      struct list_head* dirty_realms)

{

	struct ceph_snap_realm *parent = realm->parent;

	struct ceph_snap_context *snapc;
@@ -313,7 +314,7 @@ static int build_snap_context(struct ceph_snap_realm *realm) 
	 */

	if (parent) {

		if (!parent->cached_context) {

			err = build_snap_context(parent);

			err = build_snap_context(parent, dirty_realms);

			if (err)

				goto fail;

		}
@@ -373,7 +374,11 @@ static int build_snap_context(struct ceph_snap_realm *realm) 
	     realm->ino, realm, snapc, snapc->seq,

	     (unsigned int) snapc->num_snaps);



	if (realm->cached_context) {

		ceph_put_snap_context(realm->cached_context);

		/* queue realm for cap_snap creation */

		list_add_tail(&realm->dirty_item, dirty_realms);

	}

	realm->cached_context = snapc;

	return 0;
@@ -394,15 +399,16 @@ static int build_snap_context(struct ceph_snap_realm *realm) 
/*

 * rebuild snap context for the given realm and all of its children.

 */

static void rebuild_snap_realms(struct ceph_snap_realm *realm)

static void rebuild_snap_realms(struct ceph_snap_realm *realm,

				struct list_head *dirty_realms)

{

	struct ceph_snap_realm *child;



	dout("rebuild_snap_realms %llx %p\n", realm->ino, realm);

	build_snap_context(realm);

	build_snap_context(realm, dirty_realms);



	list_for_each_entry(child, &realm->children, child_item)

		rebuild_snap_realms(child);

		rebuild_snap_realms(child, dirty_realms);

}
@@ -624,13 +630,11 @@ static void queue_realm_cap_snaps(struct ceph_snap_realm *realm) 
{

	struct ceph_inode_info *ci;

	struct inode *lastinode = NULL;

	struct ceph_snap_realm *child;



	dout("queue_realm_cap_snaps %p %llx inodes\n", realm, realm->ino);



	spin_lock(&realm->inodes_with_caps_lock);

	list_for_each_entry(ci, &realm->inodes_with_caps,

			    i_snap_realm_item) {

	list_for_each_entry(ci, &realm->inodes_with_caps, i_snap_realm_item) {

		struct inode *inode = igrab(&ci->vfs_inode);

		if (!inode)

			continue;
@@ -643,14 +647,6 @@ static void queue_realm_cap_snaps(struct ceph_snap_realm *realm) 
	spin_unlock(&realm->inodes_with_caps_lock);

	iput(lastinode);



	list_for_each_entry(child, &realm->children, child_item) {

		dout("queue_realm_cap_snaps %p %llx queue child %p %llx\n",

		     realm, realm->ino, child, child->ino);

		list_del_init(&child->dirty_item);

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

	}



	list_del_init(&realm->dirty_item);

	dout("queue_realm_cap_snaps %p %llx done\n", realm, realm->ino);

}
@@ -721,8 +717,6 @@ 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);

		if (realm->seq > mdsc->last_snap_seq)

			mdsc->last_snap_seq = realm->seq;
@@ -741,7 +735,7 @@ int ceph_update_snap_trace(struct ceph_mds_client *mdsc, 


	/* invalidate when we reach the _end_ (root) of the trace */

	if (invalidate && p >= e)

		rebuild_snap_realms(realm);

		rebuild_snap_realms(realm, &dirty_realms);



	if (!first_realm)

		first_realm = realm;
@@ -758,6 +752,7 @@ int ceph_update_snap_trace(struct ceph_mds_client *mdsc, 
	while (!list_empty(&dirty_realms)) {

		realm = list_first_entry(&dirty_realms, struct ceph_snap_realm,

					 dirty_item);

		list_del_init(&realm->dirty_item);

		queue_realm_cap_snaps(realm);

	}