[PATCH] init: open /initrd.image with O_LARGEFILE

[PATCH] init: open /initrd.image with O_LARGEFILE

[John Sperbeck]

If initrd data is larger than 2Gb, we'll eventually fail to write to
the /initrd.image file when we hit that limit, unless O_LARGEFILE is set.

Signed-off-by: John Sperbeck <jsperbeck@google.com>
---
 init/initramfs.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/init/initramfs.c b/init/initramfs.c
index 76deb48c38cb..b607d3463b47 100644
--- a/init/initramfs.c
+++ b/init/initramfs.c
@@ -683,7 +683,7 @@ static void __init populate_initrd_image(char *err)
 
 	printk(KERN_INFO "rootfs image is not initramfs (%s); looks like an initrd\n",
 			err);
-	file = filp_open("/initrd.image", O_WRONLY | O_CREAT, 0700);
+	file = filp_open("/initrd.image", O_WRONLY|O_CREAT|O_LARGEFILE, 0700);
 	if (IS_ERR(file))
 		return;
 
-- 
2.44.0.291.gc1ea87d7ee-goog

Re: [PATCH] init: open /initrd.image with O_LARGEFILE

[Randy Dunlap]

Hi,

On 3/17/24 15:15, John Sperbeck wrote:
> If initrd data is larger than 2Gb, we'll eventually fail to write to
> the /initrd.image file when we hit that limit, unless O_LARGEFILE is set.
> 

Could this be related to
https://lore.kernel.org/lkml/CAHY78BqCpMQptPN0SMaXuRqHOhYi+wnMEUSTYt7OHDZih4e7yQ@mail.gmail.com/
?

Thanks.

> Signed-off-by: John Sperbeck <jsperbeck@google.com>
> ---
>  init/initramfs.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/init/initramfs.c b/init/initramfs.c
> index 76deb48c38cb..b607d3463b47 100644
> --- a/init/initramfs.c
> +++ b/init/initramfs.c
> @@ -683,7 +683,7 @@ static void __init populate_initrd_image(char *err)
>  
>  	printk(KERN_INFO "rootfs image is not initramfs (%s); looks like an initrd\n",
>  			err);
> -	file = filp_open("/initrd.image", O_WRONLY | O_CREAT, 0700);
> +	file = filp_open("/initrd.image", O_WRONLY|O_CREAT|O_LARGEFILE, 0700);
>  	if (IS_ERR(file))
>  		return;
>  

-- 
#Randy

Re: [PATCH] init: open /initrd.image with O_LARGEFILE

[John Sperbeck]

On Sun, Mar 17, 2024 at 4:47 PM Randy Dunlap <rdunlap@infradead.org> wrote:
>
> Hi,
>
> On 3/17/24 15:15, John Sperbeck wrote:
> > If initrd data is larger than 2Gb, we'll eventually fail to write to
> > the /initrd.image file when we hit that limit, unless O_LARGEFILE is set.
> >
>
> Could this be related to
> https://lore.kernel.org/lkml/CAHY78BqCpMQptPN0SMaXuRqHOhYi+wnMEUSTYt7OHDZih4e7yQ@mail.gmail.com/
> ?
>
> Thanks.
>

I think there's a separate problem that this patch doesn't address.
If an individual component of a CPIO file is larger than 2Gb, then
there will be an EFBIG error when processing it.  The backtrace where
this occurs would be:

    generic_write_checks_count
    generic_write_checks
    generic_file_write_iter
    __kernel_write_iter
    kernel_write
    xwrite
    do_copy
    unpack_to_rootfs
    do_populate_rootfs
    async_run_entry_fn
    process_scheduled_works
    worker_thread
    kthread
    ret_from_fork
    ret_from_fork_asm

I think that could be dealt with by a patch to add O_LARGEFILE to
'openflags' in initramfs:do_name().