ceph: fix getxattr vxattr handling

Change the vxattr handling for getxattr so that vxattrs are checked
prior to any xattr content, and never after.  Enforce vxattr existence
via the exists_cb callback.

Signed-off-by: Sage Weil <sage@inktank.com>
Reviewed-by: Sam Lang <sam.lang@inktank.com>

1 files changed, 8 insertions, 12 deletions

diff --git a/fs/ceph/xattr.c b/fs/ceph/xattr.c
index 06344da4e968..87b85f3403d4 100644
--- a/fs/ceph/xattr.c
+++ b/fs/ceph/xattr.c
@@ -569,13 +569,17 @@ ssize_t ceph_getxattr(struct dentry *dentry, const char *name, void *value,
         if (!ceph_is_valid_xattr(name))
                 return -ENODATA;
 
-        /* let's see if a virtual xattr was requested */
-        vxattr = ceph_match_vxattr(inode, name);
-
         spin_lock(&ci->i_ceph_lock);
         dout("getxattr %p ver=%lld index_ver=%lld\n", inode,
              ci->i_xattrs.version, ci->i_xattrs.index_version);
 
+        /* let's see if a virtual xattr was requested */
+        vxattr = ceph_match_vxattr(inode, name);
+        if (vxattr && !(vxattr->exists_cb && !vxattr->exists_cb(ci))) {
+                err = vxattr->getxattr_cb(ci, value, size);
+                goto out;
+        }
+
         if (__ceph_caps_issued_mask(ci, CEPH_CAP_XATTR_SHARED, 1) &&
             (ci->i_xattrs.index_version >= ci->i_xattrs.version)) {
                 goto get_xattr;
@@ -589,11 +593,6 @@ ssize_t ceph_getxattr(struct dentry *dentry, const char *name, void *value,
 
         spin_lock(&ci->i_ceph_lock);
 
-        if (vxattr && vxattr->readonly) {
-                err = vxattr->getxattr_cb(ci, value, size);
-                goto out;
-        }
-
         err = __build_xattrs(inode);
         if (err < 0)
                 goto out;
@@ -601,11 +600,8 @@ ssize_t ceph_getxattr(struct dentry *dentry, const char *name, void *value,
 get_xattr:
         err = -ENODATA;  /* == ENOATTR */
         xattr = __get_xattr(ci, name);
-        if (!xattr) {
-                if (vxattr)
-                        err = vxattr->getxattr_cb(ci, value, size);
+        if (!xattr)
                 goto out;
-        }
 
         err = -ERANGE;
         if (size && size < xattr->val_len)