vfs: Distinguish between full xattr names and proper prefixes

Add an additional "name" field to struct xattr_handler.  When the name
is set, the handler matches attributes with exactly that name.  When the
prefix is set instead, the handler matches attributes with the given
prefix and with a non-empty suffix.

This patch should avoid bugs like the one fixed in commit c361016a in
the future.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Reviewed-by: James Morris <james.l.morris@oracle.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 0 insertions, 4 deletions

diff --git a/fs/9p/xattr.c b/fs/9p/xattr.c
index e3d026ac382e..9dd9b47a6c1a 100644
--- a/fs/9p/xattr.c
+++ b/fs/9p/xattr.c
@@ -143,8 +143,6 @@ static int v9fs_xattr_handler_get(const struct xattr_handler *handler,
 {
 	const char *full_name = xattr_full_name(handler, name);
 
-	if (strcmp(name, "") == 0)
-		return -EINVAL;
 	return v9fs_xattr_get(dentry, full_name, buffer, size);
 }
 
@@ -154,8 +152,6 @@ static int v9fs_xattr_handler_set(const struct xattr_handler *handler,
 {
 	const char *full_name = xattr_full_name(handler, name);
 
-	if (strcmp(name, "") == 0)
-		return -EINVAL;
 	return v9fs_xattr_set(dentry, full_name, value, size, flags);
 }