Commit 829ad4db authored by Jeff Layton's avatar Jeff Layton Committed by Ilya Dryomov
Browse files

ceph: ceph_kick_flushing_caps needs the s_mutex 



The mdsc->cap_dirty_lock is not held while walking the list in
ceph_kick_flushing_caps, which is not safe.

ceph_early_kick_flushing_caps does something similar, but the
s_mutex is held while it's called and I think that guards against
changes to the list.

Ensure we hold the s_mutex when calling ceph_kick_flushing_caps,
and add some clarifying comments.

Signed-off-by: default avatarJeff Layton <jlayton@kernel.org>
Reviewed-by: default avatar"Yan, Zheng" <zyan@redhat.com>
Signed-off-by: default avatarIlya Dryomov <idryomov@gmail.com>
parent d67c72e6

fs/ceph/caps.c

+2 −0
Original line number Diff line number Diff line
@@ -2518,6 +2518,8 @@ void ceph_kick_flushing_caps(struct ceph_mds_client *mdsc, 
	struct ceph_cap *cap;

	u64 oldest_flush_tid;



	lockdep_assert_held(&session->s_mutex);



	dout("kick_flushing_caps mds%d\n", session->s_mds);



	spin_lock(&mdsc->cap_dirty_lock);

fs/ceph/mds_client.c

+2 −0
Original line number Diff line number Diff line
@@ -4024,7 +4024,9 @@ static void check_new_map(struct ceph_mds_client *mdsc, 
			    oldstate != CEPH_MDS_STATE_STARTING)

				pr_info("mds%d recovery completed\n", s->s_mds);

			kick_requests(mdsc, i);

			mutex_lock(&s->s_mutex);

			ceph_kick_flushing_caps(mdsc, s);

			mutex_unlock(&s->s_mutex);

			wake_up_session_caps(s, RECONNECT);

		}

	}

fs/ceph/mds_client.h

+3 −1
Original line number Diff line number Diff line
@@ -199,8 +199,10 @@ struct ceph_mds_session { 
	struct list_head  s_cap_releases; /* waiting cap_release messages */

	struct work_struct s_cap_release_work;



	/* both protected by s_mdsc->cap_dirty_lock */

	/* See ceph_inode_info->i_dirty_item. */

	struct list_head  s_cap_dirty;	      /* inodes w/ dirty caps */



	/* See ceph_inode_info->i_flushing_item. */

	struct list_head  s_cap_flushing;     /* inodes w/ flushing caps */



	unsigned long     s_renew_requested; /* last time we sent a renew req */

fs/ceph/super.h

+5 −2
Original line number Diff line number Diff line
@@ -362,8 +362,11 @@ struct ceph_inode_info { 
	struct list_head i_dirty_item;



	/*

	 * Link to session's s_cap_flushing list. Protected by

	 * mdsc->cap_dirty_lock.

	 * Link to session's s_cap_flushing list. Protected in a similar

	 * fashion to i_dirty_item, but also by the s_mutex for changes. The

	 * s_cap_flushing list can be walked while holding either the s_mutex

	 * or msdc->cap_dirty_lock. List presence can also be checked while

	 * holding the i_ceph_lock for this inode.

	 */

	struct list_head i_flushing_item;

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