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authorJeff Layton2020-04-03 13:09:07 -0400
committerIlya Dryomov2020-06-01 13:22:53 +0200
commit829ad4db952aac86d11a62647d2516ab46c2fcd2 (patch)
tree3ff8e570a00668a6e17a0f27d3b5ced8a4dd4089
parentd67c72e6cce99eab5ab9d62c599e33e5141ff8b4 (diff)
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: Jeff Layton <jlayton@kernel.org> Reviewed-by: "Yan, Zheng" <zyan@redhat.com> Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
-rw-r--r--fs/ceph/caps.c2
-rw-r--r--fs/ceph/mds_client.c2
-rw-r--r--fs/ceph/mds_client.h4
-rw-r--r--fs/ceph/super.h7
4 files changed, 12 insertions, 3 deletions
diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
index 2558fd14126a..41eb999dadf0 100644
--- a/fs/ceph/caps.c
+++ b/fs/ceph/caps.c
@@ -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);
diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index 588221b9b3d0..6c283c52d401 100644
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -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);
}
}
diff --git a/fs/ceph/mds_client.h b/fs/ceph/mds_client.h
index 788182adcc51..43111e408fa2 100644
--- a/fs/ceph/mds_client.h
+++ b/fs/ceph/mds_client.h
@@ -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 */
diff --git a/fs/ceph/super.h b/fs/ceph/super.h
index 3a95395a4217..b82f82d8213a 100644
--- a/fs/ceph/super.h
+++ b/fs/ceph/super.h
@@ -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;