path: root/fs/ceph/dir.c
diff options
authorAlex Elder <elder@dreamhost.com>2012-01-12 17:48:10 -0800
committerSage Weil <sage@newdream.net>2012-02-02 12:49:19 -0800
commitd8fb02abdc39f92a1066313e2b17047876afa8f9 (patch)
tree32f8126683dd185411b701b79d23900cf6c02035 /fs/ceph/dir.c
parent32852a81bccd9e3d1953b894966393d1b546576d (diff)
ceph: create a new session lock to avoid lock inversion
Lockdep was reporting a possible circular lock dependency in dentry_lease_is_valid(). That function needs to sample the session's s_cap_gen and and s_cap_ttl fields coherently, but needs to do so while holding a dentry lock. The s_cap_lock field was being used to protect the two fields, but that can't be taken while holding a lock on a dentry within the session. In most cases, the s_cap_gen and s_cap_ttl fields only get operated on separately. But in three cases they need to be updated together. Implement a new lock to protect the spots updating both fields atomically is required. Signed-off-by: Alex Elder <elder@dreamhost.com> Reviewed-by: Sage Weil <sage@newdream.net>
Diffstat (limited to 'fs/ceph/dir.c')
1 files changed, 2 insertions, 2 deletions
diff --git a/fs/ceph/dir.c b/fs/ceph/dir.c
index 98954003a8d..63c52f33361 100644
--- a/fs/ceph/dir.c
+++ b/fs/ceph/dir.c
@@ -975,10 +975,10 @@ static int dentry_lease_is_valid(struct dentry *dentry)
di = ceph_dentry(dentry);
if (di && di->lease_session) {
s = di->lease_session;
- spin_lock(&s->s_cap_lock);
+ spin_lock(&s->s_gen_ttl_lock);
gen = s->s_cap_gen;
ttl = s->s_cap_ttl;
- spin_unlock(&s->s_cap_lock);
+ spin_unlock(&s->s_gen_ttl_lock);
if (di->lease_gen == gen &&
time_before(jiffies, dentry->d_time) &&