ceph: handle cap export race in try_flush_caps()
auth cap may change after releasing the i_ceph_lock
Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
index 80dad0d..1012099 100644
--- a/fs/ceph/caps.c
+++ b/fs/ceph/caps.c
@@ -1735,13 +1735,12 @@
/*
* Try to flush dirty caps back to the auth mds.
*/
-static int try_flush_caps(struct inode *inode, struct ceph_mds_session *session,
- unsigned *flush_tid)
+static int try_flush_caps(struct inode *inode, unsigned *flush_tid)
{
struct ceph_mds_client *mdsc = ceph_sb_to_client(inode->i_sb)->mdsc;
struct ceph_inode_info *ci = ceph_inode(inode);
- int unlock_session = session ? 0 : 1;
int flushing = 0;
+ struct ceph_mds_session *session = NULL;
retry:
spin_lock(&ci->i_ceph_lock);
@@ -1755,13 +1754,14 @@
int want = __ceph_caps_wanted(ci);
int delayed;
- if (!session) {
+ if (!session || session != cap->session) {
spin_unlock(&ci->i_ceph_lock);
+ if (session)
+ mutex_unlock(&session->s_mutex);
session = cap->session;
mutex_lock(&session->s_mutex);
goto retry;
}
- BUG_ON(session != cap->session);
if (cap->session->s_state < CEPH_MDS_SESSION_OPEN)
goto out;
@@ -1780,7 +1780,7 @@
out:
spin_unlock(&ci->i_ceph_lock);
out_unlocked:
- if (session && unlock_session)
+ if (session)
mutex_unlock(&session->s_mutex);
return flushing;
}
@@ -1865,7 +1865,7 @@
return ret;
mutex_lock(&inode->i_mutex);
- dirty = try_flush_caps(inode, NULL, &flush_tid);
+ dirty = try_flush_caps(inode, &flush_tid);
dout("fsync dirty caps are %s\n", ceph_cap_string(dirty));
/*
@@ -1900,7 +1900,7 @@
dout("write_inode %p wait=%d\n", inode, wait);
if (wait) {
- dirty = try_flush_caps(inode, NULL, &flush_tid);
+ dirty = try_flush_caps(inode, &flush_tid);
if (dirty)
err = wait_event_interruptible(ci->i_cap_wq,
caps_are_flushed(inode, flush_tid));