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.

Christoph Hellwig committed 6 years ago

Commit 09267de1 parent c60166f6 files · +19 −4Browse files

Unified · Split

6 files

fs/init.c +14 −0
fs/internal.h +1 −0
fs/namespace.c +2 −2
include/linux/init_syscalls.h +1 −0
include/linux/syscalls.h +0 −1
init/do_mounts_initrd.c +1 −1

fs/init.c+14−0

@@ -23,3 +23,17 @@ int __init init_mount(const char dev_name, const char dir_name, · 22 unmodified lines
23	23	path_put(&path);
24	24	return ret;
25	25	}
	26	+
	27	+int __init init_umount(const char *name, int flags)
	28	+{
	29	+ int lookup_flags = LOOKUP_MOUNTPOINT;
	30	+ struct path path;
	31	+ int ret;
	32	+
	33	+ if (!(flags & UMOUNT_NOFOLLOW))
	34	+ lookup_flags \|= LOOKUP_FOLLOW;
	35	+ ret = kern_path(name, lookup_flags, &path);
	36	+ if (ret)
	37	+ return ret;
	38	+ return path_umount(&path, flags);
	39	+}

fs/internal.h+1−0

@@ -92,6 +92,7 @@ extern void dissolve_on_fput(struct vfsmount *); · 91 unmodified lines
92	92
93	93	int path_mount(const char dev_name, struct path path,
94	94	const char type_page, unsigned long flags, void data_page);
	95	+int path_umount(struct path *path, int flags);
95	96
96	97	/*
97	98	* fs_struct.c

fs/namespace.c+2−2

@@ -1706,7 +1706,7 @@ static inline bool may_mandlock(void) · 1705 unmodified lines
1706	1706	}
1707	1707	#endif
1708	1708
1709		−static int path_umount(struct path *path, int flags)
	1709	+int path_umount(struct path *path, int flags)
1710	1710	{
1711	1711	struct mount *mnt;
1712	1712	int retval;
@@ -1736,7 +1736,7 @@ dput_and_out: · 23 unmodified lines
1736	1736	return retval;
1737	1737	}
1738	1738
1739		−int ksys_umount(char __user *name, int flags)
	1739	+static int ksys_umount(char __user *name, int flags)
1740	1740	{
1741	1741	int lookup_flags = LOOKUP_MOUNTPOINT;
1742	1742	struct path path;

include/linux/init_syscalls.h+1−0

@@ -2,3 +2,4 @@ · 1 unmodified line
2	2
3	3	int __init init_mount(const char dev_name, const char dir_name,
4	4	const char type_page, unsigned long flags, void data_page);
	5	+int __init init_umount(const char *name, int flags);

include/linux/syscalls.h+0−1

@@ -1236,7 +1236,6 @@ asmlinkage long sys_ni_syscall(void); · 1235 unmodified lines
1236	1236	* the ksys_xyzyyz() functions prototyped below.
1237	1237	*/
1238	1238
1239		−int ksys_umount(char __user *name, int flags);
1240	1239	int ksys_chroot(const char __user *filename);
1241	1240	ssize_t ksys_write(unsigned int fd, const char __user *buf, size_t count);
1242	1241	int ksys_chdir(const char __user *filename);

init/do_mounts_initrd.c+1−1

@@ -122,7 +122,7 @@ static void __init handle_initrd(void) · 121 unmodified lines
122	122	else
123	123	printk("failed\n");
124	124	printk(KERN_NOTICE "Unmounting old root\n");
125		− ksys_umount("/old", MNT_DETACH);
	125	+ init_umount("/old", MNT_DETACH);
126	126	}
127	127	}
128	128