From 09267defa36aaff6ff829bd2fc8b043ec151cc3e Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Thu, 23 Jul 2020 08:23:08 +0200 Subject: [PATCH] init: add an init_umount helper Like ksys_umount, but takes a kernel pointer for the destination path. Switch over the umount in the init code, which just happen to work due to the implicit set_fs(KERNEL_DS) during early init right now. Signed-off-by: Christoph Hellwig --- fs/init.c | 14 ++++++++++++++ fs/internal.h | 1 + fs/namespace.c | 4 ++-- include/linux/init_syscalls.h | 1 + include/linux/syscalls.h | 1 - init/do_mounts_initrd.c | 2 +- 6 files changed, 19 insertions(+), 4 deletions(-) diff --git a/fs/init.c b/fs/init.c index c6eb724e1c7b..9c8e31fdb048 100644 --- a/fs/init.c +++ b/fs/init.c @@ -23,3 +23,17 @@ int __init init_mount(const char *dev_name, const char *dir_name, path_put(&path); return ret; } + +int __init init_umount(const char *name, int flags) +{ + int lookup_flags = LOOKUP_MOUNTPOINT; + struct path path; + int ret; + + if (!(flags & UMOUNT_NOFOLLOW)) + lookup_flags |= LOOKUP_FOLLOW; + ret = kern_path(name, lookup_flags, &path); + if (ret) + return ret; + return path_umount(&path, flags); +} diff --git a/fs/internal.h b/fs/internal.h index 72ea0b6f7435..491d1e63809b 100644 --- a/fs/internal.h +++ b/fs/internal.h @@ -92,6 +92,7 @@ extern void dissolve_on_fput(struct vfsmount *); int path_mount(const char *dev_name, struct path *path, const char *type_page, unsigned long flags, void *data_page); +int path_umount(struct path *path, int flags); /* * fs_struct.c diff --git a/fs/namespace.c b/fs/namespace.c index 2c4d75920974..a7301790abb2 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -1706,7 +1706,7 @@ static inline bool may_mandlock(void) } #endif -static int path_umount(struct path *path, int flags) +int path_umount(struct path *path, int flags) { struct mount *mnt; int retval; @@ -1736,7 +1736,7 @@ dput_and_out: return retval; } -int ksys_umount(char __user *name, int flags) +static int ksys_umount(char __user *name, int flags) { int lookup_flags = LOOKUP_MOUNTPOINT; struct path path; diff --git a/include/linux/init_syscalls.h b/include/linux/init_syscalls.h index af9ea88a60e0..a5a2e7f19916 100644 --- a/include/linux/init_syscalls.h +++ b/include/linux/init_syscalls.h @@ -2,3 +2,4 @@ int __init init_mount(const char *dev_name, const char *dir_name, const char *type_page, unsigned long flags, void *data_page); +int __init init_umount(const char *name, int flags); diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h index e43816198e60..1a4f5d8ee704 100644 --- a/include/linux/syscalls.h +++ b/include/linux/syscalls.h @@ -1236,7 +1236,6 @@ asmlinkage long sys_ni_syscall(void); * the ksys_xyzyyz() functions prototyped below. */ -int ksys_umount(char __user *name, int flags); int ksys_chroot(const char __user *filename); ssize_t ksys_write(unsigned int fd, const char __user *buf, size_t count); int ksys_chdir(const char __user *filename); diff --git a/init/do_mounts_initrd.c b/init/do_mounts_initrd.c index 1f9336209ad9..6b020a069902 100644 --- a/init/do_mounts_initrd.c +++ b/init/do_mounts_initrd.c @@ -122,7 +122,7 @@ static void __init handle_initrd(void) else printk("failed\n"); printk(KERN_NOTICE "Unmounting old root\n"); - ksys_umount("/old", MNT_DETACH); + init_umount("/old", MNT_DETACH); } }