ceph: getattr before read on ceph.* xattrs

Previously we were returning values for quota, layout
xattrs without any kind of update -- the user just got
whatever happened to be in our cache.

Clearly this extra round trip has a cost, but reads of
these xattrs are fairly rare, happening on admin
intervention rather than in normal operation.

Link: http://tracker.ceph.com/issues/17939
Signed-off-by: "Yan, Zheng" <zyan@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

diff --git a/fs/ceph/xattr.c b/fs/ceph/xattr.c
index 75267cd..11263f1 100644 (file)
--- a/fs/ceph/xattr.c
+++ b/fs/ceph/xattr.c
@@ -756,6 +756,9 @@ ssize_t __ceph_getxattr(struct inode *inode, const char *name, void *value,
        /* let's see if a virtual xattr was requested */
        vxattr = ceph_match_vxattr(inode, name);
        if (vxattr) {
+               err = ceph_do_getattr(inode, 0, true);
+               if (err)
+                       return err;
                err = -ENODATA;
                if (!(vxattr->exists_cb && !vxattr->exists_cb(ci)))
                        err = vxattr->getxattr_cb(ci, value, size);