Like ksys_umount, but takes a kernel pointer for the destination path.
Switch over the umount in the init code to it, which just happens to work
due to the implicit set_fs(KERNEL_DS) during early init right now.
Signed-off-by: Christoph Hellwig <h...@lst.de>
---
fs/namespace.c | 53 ++++++++++++++++++++++++----------------
include/linux/fs.h | 1 +
include/linux/syscalls.h | 1 -
init/do_mounts_initrd.c | 2 +-
4 files changed, 34 insertions(+), 23 deletions(-)
diff --git a/fs/namespace.c b/fs/namespace.c
index d208a389aac3c0..cfcee6a1bd5dd2 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -1706,36 +1706,26 @@ static inline bool may_mandlock(void)
}
#endif
-/*
- * Now umount can handle mount points as well as block devices.
- * This is important for filesystems which use unnamed block devices.
- *
- * We now support a flag for forced unmount like the other 'big iron'
- * unixes. Our API is identical to OSF/1 to avoid making a mess of AMD
- */
+static int umount_lookup_flags(int flags)
+{
+ if (flags & UMOUNT_NOFOLLOW)
+ return LOOKUP_MOUNTPOINT;
+ return LOOKUP_MOUNTPOINT | LOOKUP_FOLLOW;
+}
-int ksys_umount(char __user *name, int flags)
+static int path_umount(struct path *path, int flags)
{
- struct path path;
struct mount *mnt;
int retval;
- int lookup_flags = LOOKUP_MOUNTPOINT;
if (flags & ~(MNT_FORCE | MNT_DETACH | MNT_EXPIRE | UMOUNT_NOFOLLOW))
return -EINVAL;
-
if (!may_mount())
return -EPERM;
- if (!(flags & UMOUNT_NOFOLLOW))
- lookup_flags |= LOOKUP_FOLLOW;
-
- retval = user_path_at(AT_FDCWD, name, lookup_flags, &path);
- if (retval)
- goto out;
- mnt = real_mount(path.mnt);
+ mnt = real_mount(path->mnt);
retval = -EINVAL;
- if (path.dentry != path.mnt->mnt_root)
+ if (path->dentry != path->mnt->mnt_root)
goto dput_and_out;
if (!check_mnt(mnt))
goto dput_and_out;
@@ -1748,12 +1738,33 @@ int ksys_umount(char __user *name, int flags)
retval = do_umount(mnt, flags);
dput_and_out:
/* we mustn't call path_put() as that would clear mnt_expiry_mark */
- dput(path.dentry);
+ dput(path->dentry);
mntput_no_expire(mnt);
-out:
return retval;
}
+static int ksys_umount(char __user *name, int flags)
+{
+ struct path path;
+ int ret;
+
+ ret = user_path_at(AT_FDCWD, name, umount_lookup_flags(flags), &path);
+ if (ret)
+ return ret;
+ return path_umount(&path, flags);
+}
+
+int __init kern_umount(char *name, int flags)
+{
+ struct path path;
+ int ret;
+
+ ret = kern_path(name, umount_lookup_flags(flags), &path);
+ if (ret)
+ return ret;
+ return path_umount(&path, flags);
+}
+
SYSCALL_DEFINE2(umount, char __user *, name, int, flags)
{
return ksys_umount(name, flags);
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 8f628f9868711d..fbeadaa1a185fb 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2339,6 +2339,7 @@ extern long do_mount(const char *, const char __user *,
const char *, unsigned long, void *);
int do_kern_mount(const char *dev_name, const char *dir_name,
const char *type_page, unsigned long flags, void *data_page);
+int __init kern_umount(char *name, int flags);
extern struct vfsmount *collect_mounts(const struct path *);
extern void drop_collected_mounts(struct vfsmount *);
extern int iterate_mounts(int (*)(struct vfsmount *, void *), void *,
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 5b0f1fca4cfb9d..3b1b8ebcda1d8c 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 604ce78af9acfa..d3858620707893 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);
+ kern_umount("/old", MNT_DETACH);
}
}
--
2.27.0
