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| author | Jeff Layton <jlayton@redhat.com> | 2016-12-15 08:37:58 -0500 |
|---|---|---|
| committer | Ilya Dryomov <idryomov@gmail.com> | 2017-02-20 12:16:05 +0100 |
| commit | adf0d68701c7f3e50f21308c76f41e60956a6832 (patch) | |
| tree | 82927817ebd1d9d064a2278d42f8b999b2ac7fe4 | |
| parent | fd36a71762f3b0fcb9741ed24021afabec7e0c45 (diff) | |
| download | linux-adf0d68701c7f3e50f21308c76f41e60956a6832.tar.gz linux-adf0d68701c7f3e50f21308c76f41e60956a6832.tar.xz | |
ceph: fix unsafe dcache access in ceph_encode_dentry_release
Accessing d_parent requires some sort of locking or it could vanish
out from under us. Since we take the d_lock anyway, use that to fetch
d_parent and take a reference to it, and then use that reference to
call ceph_encode_inode_release.
Link: http://tracker.ceph.com/issues/18148
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Reviewed-by: Yan, Zheng <zyan@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
| -rw-r--r-- | fs/ceph/caps.c | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c index 94fd76d04683..d1b4c543cab1 100644 --- a/fs/ceph/caps.c +++ b/fs/ceph/caps.c @@ -3926,7 +3926,7 @@ int ceph_encode_inode_release(void **p, struct inode *inode, int ceph_encode_dentry_release(void **p, struct dentry *dentry, int mds, int drop, int unless) { - struct inode *dir = d_inode(dentry->d_parent); + struct dentry *parent; struct ceph_mds_request_release *rel = *p; struct ceph_dentry_info *di = ceph_dentry(dentry); int force = 0; @@ -3941,9 +3941,12 @@ int ceph_encode_dentry_release(void **p, struct dentry *dentry, spin_lock(&dentry->d_lock); if (di->lease_session && di->lease_session->s_mds == mds) force = 1; + parent = dget(dentry->d_parent); spin_unlock(&dentry->d_lock); - ret = ceph_encode_inode_release(p, dir, mds, drop, unless, force); + ret = ceph_encode_inode_release(p, d_inode(parent), mds, drop, + unless, force); + dput(parent); spin_lock(&dentry->d_lock); if (ret && di->lease_session && di->lease_session->s_mds == mds) { |