Factor out a path_umount helper that takes a struct path * instead of the
actual file name. This will allow to convert the init and devtmpfs code
to properly mount based on a kernel pointer instead of relying on the
implicit set_fs(KERNEL_DS) during early init.
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
fs/namespace.c | 40 ++++++++++++++++++----------------------
1 file changed, 18 insertions(+), 22 deletions(-)
diff --git a/fs/namespace.c b/fs/namespace.c
index 6f8234f74bed90..43834b59eff6c3 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -1706,36 +1706,19 @@ 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
- */
-
-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 +1731,25 @@ 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;
}
+int ksys_umount(char __user *name, int flags)
+{
+ int lookup_flags = LOOKUP_MOUNTPOINT;
+ struct path path;
+ int ret;
+
+ if (!(flags & UMOUNT_NOFOLLOW))
+ lookup_flags |= LOOKUP_FOLLOW;
+ ret = user_path_at(AT_FDCWD, name, lookup_flags, &path);
+ if (ret)
+ return ret;
+ return path_umount(&path, flags);
+}
+
SYSCALL_DEFINE2(umount, char __user *, name, int, flags)
{
return ksys_umount(name, flags);
--
2.27.0
