The patch titled
Subject: initramfs: clean old path before creating a hardlink
has been added to the -mm tree. Its filename is
initramfs-clean-old-path-before-creating-a-hardlink.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/initramfs-clean-old-path-before-creating-a-hardlink.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/initramfs-clean-old-path-before-creating-a-hardlink.patch
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------------------------------------------------------
From: Li Zhijian <lizhijian@xxxxxxxxxxxxxx>
Subject: initramfs: clean old path before creating a hardlink
sys_link() can fail due to the new path already existing. This case ofen
occurs when we use a concated initrd, for example:
1) prepare a basic rootfs, it contains a regular files rc.local
lizhijian@:~/yocto-tiny-i386-2016-04-22$ cat etc/rc.local
#!/bin/sh
echo "Running /etc/rc.local..."
yocto-tiny-i386-2016-04-22$ find . | sed 's,^\./,,' | cpio -o -H newc | gzip -n -9 >../rootfs.cgz
2) create a extra initrd which also includes a etc/rc.local
lizhijian@:~/lkp-x86_64/etc$ echo "append initrd" >rc.local
lizhijian@:~/lkp/lkp-x86_64/etc$ cat rc.local
append initrd
lizhijian@:~/lkp/lkp-x86_64/etc$ ln rc.local rc.local.hardlink
append initrd
lizhijian@:~/lkp/lkp-x86_64/etc$ stat rc.local rc.local.hardlink
File: 'rc.local'
Size: 14 Blocks: 8 IO Block: 4096 regular file
Device: 801h/2049d Inode: 11296086 Links: 2
Access: (0664/-rw-rw-r--) Uid: ( 1002/lizhijian) Gid: ( 1002/lizhijian)
Access: 2018-11-15 16:08:28.654464815 +0800
Modify: 2018-11-15 16:07:57.514903210 +0800
Change: 2018-11-15 16:08:24.180228872 +0800
Birth: -
File: 'rc.local.hardlink'
Size: 14 Blocks: 8 IO Block: 4096 regular file
Device: 801h/2049d Inode: 11296086 Links: 2
Access: (0664/-rw-rw-r--) Uid: ( 1002/lizhijian) Gid: ( 1002/lizhijian)
Access: 2018-11-15 16:08:28.654464815 +0800
Modify: 2018-11-15 16:07:57.514903210 +0800
Change: 2018-11-15 16:08:24.180228872 +0800
Birth: -
lizhijian@:~/lkp/lkp-x86_64$ find . | sed 's,^\./,,' | cpio -o -H newc | gzip -n -9 >../rc-local.cgz
lizhijian@:~/lkp/lkp-x86_64$ gzip -dc ../rc-local.cgz | cpio -t
.
etc
etc/rc.local.hardlink <<< it will be extracted first at this initrd
etc/rc.local
3) concate 2 initrds and boot
lizhijian@:~/lkp$ cat rootfs.cgz rc-local.cgz >concate-initrd.cgz
lizhijian@:~/lkp$ qemu-system-x86_64 -nographic -enable-kvm -cpu host -smp 1 -m 1024 -kernel ~/lkp/linux/arch/x86/boot/bzImage -append "console=ttyS0 earlyprint=ttyS0 ignore_loglevel" -initrd ./concate-initr.cgz -serial stdio -nodefaults
In this case, sys_link(2) will fail and return -EEXIST, so we can only get
the rc.local at rootfs.cgz instead of rc-local.cgz
Link: http://lkml.kernel.org/r/1542352368-13299-1-git-send-email-lizhijian@xxxxxxxxxxxxxx
Signed-off-by: Li Zhijian <lizhijian@xxxxxxxxxxxxxx>
Cc: Philip Li <philip.li@xxxxxxxxx>
Cc: Dominik Brodowski <linux@xxxxxxxxxxxxxxxxxxxx>
Cc: Li Zhijian <zhijianx.li@xxxxxxxxx>
Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
--- a/init/initramfs.c~initramfs-clean-old-path-before-creating-a-hardlink
+++ a/init/initramfs.c
@@ -291,12 +291,16 @@ static int __init do_reset(void)
return 1;
}
+static void __init clean_path(char *path, umode_t fmode);
+
static int __init maybe_link(void)
{
if (nlink >= 2) {
char *old = find_link(major, minor, ino, mode, collected);
- if (old)
+ if (old) {
+ clean_path(collected, 0);
return (ksys_link(old, collected) < 0) ? -1 : 1;
+ }
}
return 0;
}
_
Patches currently in -mm which might be from lizhijian@xxxxxxxxxxxxxx are
initramfs-clean-old-path-before-creating-a-hardlink.patch
