From 7c02ca55428796cd73b9c39e5b52a85b232f2d51 Mon Sep 17 00:00:00 2001 From: Stefan Berger Date: Sun, 19 Nov 2023 20:12:48 -0500 Subject: [PATCH] rootfs: Fix support for rootfstype= when root= is given commit 21528c69a0d8483f7c6345b1a0bc8d8975e9a172 upstream. Documentation/filesystems/ramfs-rootfs-initramfs.rst states: If CONFIG_TMPFS is enabled, rootfs will use tmpfs instead of ramfs by default. To force ramfs, add "rootfstype=ramfs" to the kernel command line. This currently does not work when root= is provided since then saved_root_name contains a string and rootfstype= is ignored. Therefore, ramfs is currently always chosen when root= is provided. The current behavior for rootfs's filesystem is: root= | rootfstype= | chosen rootfs filesystem ------------+-------------+-------------------------- unspecified | unspecified | tmpfs unspecified | tmpfs | tmpfs unspecified | ramfs | ramfs provided | ignored | ramfs rootfstype= should be respected regardless whether root= is given, as shown below: root= | rootfstype= | chosen rootfs filesystem ------------+-------------+-------------------------- unspecified | unspecified | tmpfs (as before) unspecified | tmpfs | tmpfs (as before) unspecified | ramfs | ramfs (as before) provided | unspecified | ramfs (compatibility with before) provided | tmpfs | tmpfs (new) provided | ramfs | ramfs (new) This table represents the new behavior. Fixes: 6e19eded3684 ("initmpfs: use initramfs if rootfstype= or root= specified") Cc: Signed-off-by: Rob Landley Link: https://lore.kernel.org/lkml/8244c75f-445e-b15b-9dbf-266e7ca666e2@landley.net/ Reviewed-and-Tested-by: Mimi Zohar Signed-off-by: Stefan Berger Link: https://lore.kernel.org/r/20231120011248.396012-1-stefanb@linux.ibm.com Signed-off-by: Greg Kroah-Hartman --- init/do_mounts.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/init/do_mounts.c b/init/do_mounts.c index 811e94daf0a8..2d705b9c8400 100644 --- a/init/do_mounts.c +++ b/init/do_mounts.c @@ -665,7 +665,10 @@ struct file_system_type rootfs_fs_type = { void __init init_rootfs(void) { - if (IS_ENABLED(CONFIG_TMPFS) && !saved_root_name[0] && - (!root_fs_names || strstr(root_fs_names, "tmpfs"))) - is_tmpfs = true; + if (IS_ENABLED(CONFIG_TMPFS)) { + if (!saved_root_name[0] && !root_fs_names) + is_tmpfs = true; + else if (root_fs_names && !!strstr(root_fs_names, "tmpfs")) + is_tmpfs = true; + } }