diff options
| author | Alex Elder <elder@dreamhost.com> | 2012-01-12 17:48:10 -0800 |
|---|---|---|
| committer | Sage Weil <sage@newdream.net> | 2012-02-02 12:49:19 -0800 |
| commit | d8fb02abdc39f92a1066313e2b17047876afa8f9 (patch) | |
| tree | 32f8126683dd185411b701b79d23900cf6c02035 /fs/ceph/caps.c | |
| parent | 32852a81bccd9e3d1953b894966393d1b546576d (diff) | |
| download | linux-d8fb02abdc39f92a1066313e2b17047876afa8f9.tar.gz linux-d8fb02abdc39f92a1066313e2b17047876afa8f9.tar.bz2 linux-d8fb02abdc39f92a1066313e2b17047876afa8f9.zip | |
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/caps.c')
| -rw-r--r-- | fs/ceph/caps.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c index 8b53193e4f7c..90d789df9ce0 100644 --- a/fs/ceph/caps.c +++ b/fs/ceph/caps.c @@ -641,10 +641,10 @@ static int __cap_is_valid(struct ceph_cap *cap) unsigned long ttl; u32 gen; - spin_lock(&cap->session->s_cap_lock); + spin_lock(&cap->session->s_gen_ttl_lock); gen = cap->session->s_cap_gen; ttl = cap->session->s_cap_ttl; - spin_unlock(&cap->session->s_cap_lock); + spin_unlock(&cap->session->s_gen_ttl_lock); if (cap->cap_gen < gen || time_after_eq(jiffies, ttl)) { dout("__cap_is_valid %p cap %p issued %s " |