Merge tag 'vfs-6.13.ovl' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull overlayfs updates from Christian Brauner:
 "Make overlayfs support specifying layers through file descriptors.

  Currently overlayfs only allows specifying layers through path names.
  This is inconvenient for users that want to assemble an overlayfs
  mount purely based on file descriptors:

  This enables user to specify both:

    fsconfig(fd_overlay, FSCONFIG_SET_FD, "upperdir+", NULL, fd_upper);
    fsconfig(fd_overlay, FSCONFIG_SET_FD, "workdir+",  NULL, fd_work);
    fsconfig(fd_overlay, FSCONFIG_SET_FD, "lowerdir+", NULL, fd_lower1);
    fsconfig(fd_overlay, FSCONFIG_SET_FD, "lowerdir+", NULL, fd_lower2);

  in addition to:

    fsconfig(fd_overlay, FSCONFIG_SET_STRING, "upperdir+", "/upper",  0);
    fsconfig(fd_overlay, FSCONFIG_SET_STRING, "workdir+",  "/work",   0);
    fsconfig(fd_overlay, FSCONFIG_SET_STRING, "lowerdir+", "/lower1", 0);
    fsconfig(fd_overlay, FSCONFIG_SET_STRING, "lowerdir+", "/lower2", 0);

  There's also a large set of new overlayfs selftests to test new
  features and some older properties"

* tag 'vfs-6.13.ovl' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
  selftests: add test for specifying 500 lower layers
  selftests: add overlayfs fd mounting selftests
  selftests: use shared header
  Documentation,ovl: document new file descriptor based layers
  ovl: specify layers via file descriptors
  fs: add helper to use mount option as path or fd

1 files changed, 20 insertions, 0 deletions

diff --git a/fs/fs_parser.c b/fs/fs_parser.c
index 698464f3e26a..16fa61ef56bf 100644
--- a/fs/fs_parser.c
+++ b/fs/fs_parser.c
@@ -309,6 +309,26 @@ int fs_param_is_fd(struct p_log *log, const struct fs_parameter_spec *p,
 }
 EXPORT_SYMBOL(fs_param_is_fd);
 
+int fs_param_is_file_or_string(struct p_log *log,
+			       const struct fs_parameter_spec *p,
+			       struct fs_parameter *param,
+			       struct fs_parse_result *result)
+{
+	switch (param->type) {
+	case fs_value_is_string:
+		return fs_param_is_string(log, p, param, result);
+	case fs_value_is_file:
+		result->uint_32 = param->dirfd;
+		if (result->uint_32 <= INT_MAX)
+			return 0;
+		break;
+	default:
+		break;
+	}
+	return fs_param_bad_value(log, param);
+}
+EXPORT_SYMBOL(fs_param_is_file_or_string);
+
 int fs_param_is_uid(struct p_log *log, const struct fs_parameter_spec *p,
 		    struct fs_parameter *param, struct fs_parse_result *result)
 {