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authorYan, Zheng <zyan@redhat.com>2016-03-07 10:34:50 +0800
committerIlya Dryomov <idryomov@gmail.com>2016-03-25 18:51:55 +0100
commit315f24088048a51eed341c53be66ea477a3c7d16 (patch)
treeb0947756198ee556f500e2b5dd001104fec003b8 /include
parent29dccfa5af388916e48a3edc5ac9dc8cc996d9b4 (diff)
ceph: fix security xattr deadlock
When security is enabled, security module can call filesystem's getxattr/setxattr callbacks during d_instantiate(). For cephfs, d_instantiate() is usually called by MDS' dispatch thread, while handling MDS reply. If the MDS reply does not include xattrs and corresponding caps, getxattr/setxattr need to send a new request to MDS and waits for the reply. This makes MDS' dispatch sleep, nobody handles later MDS replies. The fix is make sure lookup/atomic_open reply include xattrs and corresponding caps. So getxattr can be handled by cached xattrs. This requires some modification to both MDS and request message. (Client tells MDS what caps it wants; MDS encodes proper caps in the reply) Smack security module may call setxattr during d_instantiate(). Unlike getxattr, we can't force MDS to issue CEPH_CAP_XATTR_EXCL to us. So just make setxattr return error when called by MDS' dispatch thread. Signed-off-by: Yan, Zheng <zyan@redhat.com>
Diffstat (limited to 'include')
-rw-r--r--include/linux/ceph/ceph_fs.h3
1 files changed, 2 insertions, 1 deletions
diff --git a/include/linux/ceph/ceph_fs.h b/include/linux/ceph/ceph_fs.h
index bf74005eedec..37f28bf55ce4 100644
--- a/include/linux/ceph/ceph_fs.h
+++ b/include/linux/ceph/ceph_fs.h
@@ -376,7 +376,8 @@ union ceph_mds_request_args {
__le32 stripe_count; /* ... */
__le32 object_size;
__le32 file_replication;
- __le32 unused; /* used to be preferred osd */
+ __le32 mask; /* CEPH_CAP_* */
+ __le32 old_size;
} __attribute__ ((packed)) open;
struct {
__le32 flags;