ceph: do not touch_caps while iterating over caps list
Avoid confusing iterate_session_caps(), flag the session while we are
iterating so that __touch_cap does not rearrange items on the list.
All other modifiers of session->s_caps do so under the protection of
s_mutex.
Signed-off-by: Sage Weil <sage@newdream.net>
diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
index dfb509f..93c1afe 100644
--- a/fs/ceph/caps.c
+++ b/fs/ceph/caps.c
@@ -697,10 +697,15 @@
{
struct ceph_mds_session *s = cap->session;
- dout("__touch_cap %p cap %p mds%d\n", &cap->ci->vfs_inode, cap,
- s->s_mds);
spin_lock(&s->s_cap_lock);
- list_move_tail(&cap->session_caps, &s->s_caps);
+ if (!s->s_iterating_caps) {
+ dout("__touch_cap %p cap %p mds%d\n", &cap->ci->vfs_inode, cap,
+ s->s_mds);
+ list_move_tail(&cap->session_caps, &s->s_caps);
+ } else {
+ dout("__touch_cap %p cap %p mds%d NOP, iterating over caps\n",
+ &cap->ci->vfs_inode, cap, s->s_mds);
+ }
spin_unlock(&s->s_cap_lock);
}
diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index d7cecc3..63ca3b1 100644
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -337,10 +337,12 @@
s->s_renew_seq = 0;
INIT_LIST_HEAD(&s->s_caps);
s->s_nr_caps = 0;
+ s->s_trim_caps = 0;
atomic_set(&s->s_ref, 1);
INIT_LIST_HEAD(&s->s_waiting);
INIT_LIST_HEAD(&s->s_unsafe);
s->s_num_cap_releases = 0;
+ s->s_iterating_caps = false;
INIT_LIST_HEAD(&s->s_cap_releases);
INIT_LIST_HEAD(&s->s_cap_releases_done);
INIT_LIST_HEAD(&s->s_cap_flushing);
@@ -699,6 +701,7 @@
dout("iterate_session_caps %p mds%d\n", session, session->s_mds);
spin_lock(&session->s_cap_lock);
+ session->s_iterating_caps = true;
list_for_each_entry_safe(cap, ncap, &session->s_caps, session_caps) {
inode = igrab(&cap->ci->vfs_inode);
if (!inode)
@@ -706,13 +709,15 @@
spin_unlock(&session->s_cap_lock);
ret = cb(inode, cap, arg);
iput(inode);
- if (ret < 0)
- return ret;
spin_lock(&session->s_cap_lock);
+ if (ret < 0)
+ goto out;
}
+ ret = 0;
+out:
+ session->s_iterating_caps = false;
spin_unlock(&session->s_cap_lock);
-
- return 0;
+ return ret;
}
static int remove_session_caps_cb(struct inode *inode, struct ceph_cap *cap,
@@ -935,6 +940,7 @@
dout("trim_caps mds%d done: %d / %d, trimmed %d\n",
session->s_mds, session->s_nr_caps, max_caps,
trim_caps - session->s_trim_caps);
+ session->s_trim_caps = 0;
}
return 0;
}
diff --git a/fs/ceph/mds_client.h b/fs/ceph/mds_client.h
index 41af5ca..b1c2025 100644
--- a/fs/ceph/mds_client.h
+++ b/fs/ceph/mds_client.h
@@ -114,6 +114,7 @@
int s_num_cap_releases;
struct list_head s_cap_releases; /* waiting cap_release messages */
struct list_head s_cap_releases_done; /* ready to send */
+ bool s_iterating_caps;
/* protected by mutex */
struct list_head s_cap_flushing; /* inodes w/ flushing caps */
