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authorLi Zhijian <lizhijian@cn.fujitsu.com>2018-11-30 14:10:09 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2018-11-30 14:56:14 -0800
commit7c0950d455d6ab610d2990a13120f935b75abf2c (patch)
tree44f80b767fbc70019d228c5a2d4fa70e7ba1d7f0 /init/initramfs.c
parent903e8ff86753e6f327bb92166a0665e4ecb8e2e7 (diff)
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 [akpm@linux-foundation.org: move code to avoid forward declaration] Link: http://lkml.kernel.org/r/1542352368-13299-1-git-send-email-lizhijian@cn.fujitsu.com Signed-off-by: Li Zhijian <lizhijian@cn.fujitsu.com> Cc: Philip Li <philip.li@intel.com> Cc: Dominik Brodowski <linux@dominikbrodowski.net> Cc: Li Zhijian <zhijianx.li@intel.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'init/initramfs.c')
-rw-r--r--init/initramfs.c22
1 files changed, 12 insertions, 10 deletions
diff --git a/init/initramfs.c b/init/initramfs.c
index 640557788026..f6f4a1e4cd54 100644
--- a/init/initramfs.c
+++ b/init/initramfs.c
@@ -291,16 +291,6 @@ static int __init do_reset(void)
return 1;
}
-static int __init maybe_link(void)
-{
- if (nlink >= 2) {
- char *old = find_link(major, minor, ino, mode, collected);
- if (old)
- return (ksys_link(old, collected) < 0) ? -1 : 1;
- }
- return 0;
-}
-
static void __init clean_path(char *path, umode_t fmode)
{
struct kstat st;
@@ -313,6 +303,18 @@ 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) {
+ clean_path(collected, 0);
+ return (ksys_link(old, collected) < 0) ? -1 : 1;
+ }
+ }
+ return 0;
+}
+
static __initdata int wfd;
static int __init do_name(void)

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