[PATCH v2] ksmbd: don't remove dos attribute xattr on O_TRUNC open

[Namjae Jeon <linkinjeon@kernel.org>]

When smb client open file in ksmbd share with O_TRUNC, dos attribute
xattr is removed as well as data in file. This cause the FSCTL_SET_SPARSE
request from the client fails because ksmbd can't update the dos attribute
after setting ATTR_SPARSE_FILE. And this patch fix xfstests generic/469
test also.

Fixes: e2f34481b24d ("cifsd: add server-side procedures for SMB3")
Cc: stable@vger.kernel.org
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
---
 v2:
   - don't remove other xattr class also.
   - add fixes and stable tags.

 fs/ksmbd/smb2pdu.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/fs/ksmbd/smb2pdu.c b/fs/ksmbd/smb2pdu.c
index a136d5e4943b..c2daef28a214 100644
--- a/fs/ksmbd/smb2pdu.c
+++ b/fs/ksmbd/smb2pdu.c
@@ -2330,10 +2330,9 @@ static int smb2_remove_smb_xattrs(struct path *path)
 			name += strlen(name) + 1) {
 		ksmbd_debug(SMB, "%s, len %zd\n", name, strlen(name));
 
-		if (strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN) &&
-		    strncmp(&name[XATTR_USER_PREFIX_LEN], DOS_ATTRIBUTE_PREFIX,
-			    DOS_ATTRIBUTE_PREFIX_LEN) &&
-		    strncmp(&name[XATTR_USER_PREFIX_LEN], STREAM_PREFIX, STREAM_PREFIX_LEN))
+		if (strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN) ||
+		    (!strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN) &&
+		     strncmp(&name[XATTR_USER_PREFIX_LEN], STREAM_PREFIX, STREAM_PREFIX_LEN)))
 			continue;
 
 		err = ksmbd_vfs_remove_xattr(user_ns, path->dentry, name);
-- 
2.25.1