aboutsummaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
-rw-r--r--Documentation/filesystems/ramfs-rootfs-initramfs.txt4
-rw-r--r--init/do_mounts.c15
2 files changed, 15 insertions, 4 deletions
diff --git a/Documentation/filesystems/ramfs-rootfs-initramfs.txt b/Documentation/filesystems/ramfs-rootfs-initramfs.txt
index 59b4a0962e0f..b176928e6963 100644
--- a/Documentation/filesystems/ramfs-rootfs-initramfs.txt
+++ b/Documentation/filesystems/ramfs-rootfs-initramfs.txt
@@ -79,6 +79,10 @@ to just make sure certain lists can't become empty.
Most systems just mount another filesystem over rootfs and ignore it. The
amount of space an empty instance of ramfs takes up is tiny.
+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.
+
What is initramfs?
------------------
diff --git a/init/do_mounts.c b/init/do_mounts.c
index e27908b949d4..a51cddc2ff8c 100644
--- a/init/do_mounts.c
+++ b/init/do_mounts.c
@@ -591,16 +591,20 @@ out:
sys_chroot(".");
}
+static bool is_tmpfs;
static struct dentry *rootfs_mount(struct file_system_type *fs_type,
int flags, const char *dev_name, void *data)
{
static unsigned long once;
+ void *fill = ramfs_fill_super;
if (test_and_set_bit(0, &once))
return ERR_PTR(-ENODEV);
- return mount_nodev(fs_type, flags, data,
- IS_ENABLED(CONFIG_TMPFS) ? shmem_fill_super : ramfs_fill_super);
+ if (IS_ENABLED(CONFIG_TMPFS) && is_tmpfs)
+ fill = shmem_fill_super;
+
+ return mount_nodev(fs_type, flags, data, fill);
}
static struct file_system_type rootfs_fs_type = {
@@ -616,10 +620,13 @@ int __init init_rootfs(void)
if (err)
return err;
- if (IS_ENABLED(CONFIG_TMPFS))
+ if (IS_ENABLED(CONFIG_TMPFS) && !saved_root_name[0] &&
+ (!root_fs_names || strstr(root_fs_names, "tmpfs"))) {
err = shmem_init();
- else
+ is_tmpfs = true;
+ } else {
err = init_ramfs_fs();
+ }
if (err)
unregister_filesystem(&rootfs_fs_type);

Privacy Policy