ceph: fix setting empty extended attribute

make sure 'value' is not null. otherwise __ceph_setxattr will remove
the extended attribute.

Signed-off-by: Yan, Zheng <zyan@redhat.com>
Reviewed-by: Sage Weil <sage@redhat.com>

1 files changed, 5 insertions, 2 deletions

diff --git a/fs/ceph/xattr.c b/fs/ceph/xattr.c
index 678b0d2bbbc4..5a492caf34cb 100644
--- a/fs/ceph/xattr.c
+++ b/fs/ceph/xattr.c
@@ -854,7 +854,7 @@ static int ceph_sync_setxattr(struct dentry *dentry, const char *name,
         struct ceph_pagelist *pagelist = NULL;
         int err;
 
-        if (value) {
+        if (size > 0) {
                 /* copy value into pagelist */
                 pagelist = kmalloc(sizeof(*pagelist), GFP_NOFS);
                 if (!pagelist)
@@ -864,7 +864,7 @@ static int ceph_sync_setxattr(struct dentry *dentry, const char *name,
                 err = ceph_pagelist_append(pagelist, value, size);
                 if (err)
                         goto out;
-        } else {
+        } else if (!value) {
                 flags |= CEPH_XATTR_REMOVE;
         }
 
@@ -1001,6 +1001,9 @@ int ceph_setxattr(struct dentry *dentry, const char *name,
         if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
                 return generic_setxattr(dentry, name, value, size, flags);
 
+        if (size == 0)
+                value = "";  /* empty EA, do not remove */
+
         return __ceph_setxattr(dentry, name, value, size, flags);
 }