2024-03-08 10:15:14

by 牛志国 (Zhiguo Niu)

Subject: [PATCH 1/2] f2fs: fix to remove f2fs_bug_on in add_bio_entry

add_bio_entry should not trigger system panic when bio_add_page fail,
fix to remove it.

Fixes: 0b20fcec8651 ("f2fs: cache global IPU bio")
Signed-off-by: Zhiguo Niu <[email protected]>
---
fs/f2fs/data.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index d9494b5..f8ae684 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -759,8 +759,10 @@ static void add_bio_entry(struct f2fs_sb_info *sbi, struct bio *bio,
be->bio = bio;
bio_get(bio);

- if (bio_add_page(bio, page, PAGE_SIZE, 0) != PAGE_SIZE)
- f2fs_bug_on(sbi, 1);
+ if (bio_add_page(bio, page, PAGE_SIZE, 0) != PAGE_SIZE) {
+ bio_put(bio);
+ return;
+ }

f2fs_down_write(&io->bio_list_lock);
list_add_tail(&be->list, &io->bio_list);
--
1.9.1

2024-03-11 03:54:13

by Chao Yu

Subject: Re: [PATCH 1/2] f2fs: fix to remove f2fs_bug_on in add_bio_entry

On 2024/3/8 18:12, Zhiguo Niu wrote:
> add_bio_entry should not trigger system panic when bio_add_page fail,
> fix to remove it.
>
> Fixes: 0b20fcec8651 ("f2fs: cache global IPU bio")
> Signed-off-by: Zhiguo Niu <[email protected]>
> ---
> fs/f2fs/data.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> index d9494b5..f8ae684 100644
> --- a/fs/f2fs/data.c
> +++ b/fs/f2fs/data.c
> @@ -759,8 +759,10 @@ static void add_bio_entry(struct f2fs_sb_info *sbi, struct bio *bio,
> be->bio = bio;
> bio_get(bio);
>
> - if (bio_add_page(bio, page, PAGE_SIZE, 0) != PAGE_SIZE)
> - f2fs_bug_on(sbi, 1);
> + if (bio_add_page(bio, page, PAGE_SIZE, 0) != PAGE_SIZE) {
> + bio_put(bio);

I didn't get it, why new created bio has no space to store one page?

Thanks,

> + return;
> + }
>
> f2fs_down_write(&io->bio_list_lock);
> list_add_tail(&be->list, &io->bio_list);

2024-03-11 07:26:28

by Zhiguo Niu

Subject: Re: [PATCH 1/2] f2fs: fix to remove f2fs_bug_on in add_bio_entry

On Mon, Mar 11, 2024 at 11:54 AM Chao Yu <[email protected]> wrote:
>
> On 2024/3/8 18:12, Zhiguo Niu wrote:
> > add_bio_entry should not trigger system panic when bio_add_page fail,
> > fix to remove it.
> >
> > Fixes: 0b20fcec8651 ("f2fs: cache global IPU bio")
> > Signed-off-by: Zhiguo Niu <[email protected]>
> > ---
> > fs/f2fs/data.c | 6 ++++--
> > 1 file changed, 4 insertions(+), 2 deletions(-)
> >
> > diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> > index d9494b5..f8ae684 100644
> > --- a/fs/f2fs/data.c
> > +++ b/fs/f2fs/data.c
> > @@ -759,8 +759,10 @@ static void add_bio_entry(struct f2fs_sb_info *sbi, struct bio *bio,
> > be->bio = bio;
> > bio_get(bio);
> >
> > - if (bio_add_page(bio, page, PAGE_SIZE, 0) != PAGE_SIZE)
> > - f2fs_bug_on(sbi, 1);
> > + if (bio_add_page(bio, page, PAGE_SIZE, 0) != PAGE_SIZE) {
> > + bio_put(bio);
>
> I didn't get it, why new created bio has no space to store one page?
>
> Thanks,

Dear Chao,
I got what you mean.

We are doing bio merge optimization in bio_add_page.
After looking at all the locations where bio_add_page is called,
and think it is unreasonable to panic the system if bio_add_page fails.
but it is not impossible to panic in the current flow about bio_add_page.
so keeping it as is is a good choice.
thanks!
> > + return;
> > + }
> >
> > f2fs_down_write(&io->bio_list_lock);
> > list_add_tail(&be->list, &io->bio_list);