2021-01-05 01:31:59

by Daeho Jeong

Subject: [PATCH] f2fs: fix null page reference in redirty_blocks

From: Daeho Jeong <[email protected]>

Fixed null page reference when find_lock_page() fails in
redirty_blocks().

Signed-off-by: Daeho Jeong <[email protected]>
Reported-by: Colin Ian King <[email protected]>
Fixes: 5fdb322ff2c2 ("f2fs: add F2FS_IOC_DECOMPRESS_FILE and F2FS_IOC_COMPRESS_FILE")
---
fs/f2fs/file.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 9e5275716be8..bf6682a52433 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -4060,8 +4060,10 @@ static int redirty_blocks(struct inode *inode, pgoff_t page_idx, int len)

for (i = 0; i < page_len; i++, redirty_idx++) {
page = find_lock_page(mapping, redirty_idx);
- if (!page)
+ if (!page) {
ret = -ENOENT;
+ continue;
+ }
set_page_dirty(page);
f2fs_put_page(page, 1);
f2fs_put_page(page, 0);
--
2.29.2.729.g45daf8777d-goog

2021-01-05 01:47:00

by Chao Yu

Subject: Re: [f2fs-dev] [PATCH] f2fs: fix null page reference in redirty_blocks

On 2021/1/5 9:28, Daeho Jeong wrote:
> From: Daeho Jeong <[email protected]>
>
> Fixed null page reference when find_lock_page() fails in
> redirty_blocks().
>
> Signed-off-by: Daeho Jeong <[email protected]>
> Reported-by: Colin Ian King <[email protected]>
> Fixes: 5fdb322ff2c2 ("f2fs: add F2FS_IOC_DECOMPRESS_FILE and F2FS_IOC_COMPRESS_FILE")
> ---
> fs/f2fs/file.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
> index 9e5275716be8..bf6682a52433 100644
> --- a/fs/f2fs/file.c
> +++ b/fs/f2fs/file.c
> @@ -4060,8 +4060,10 @@ static int redirty_blocks(struct inode *inode, pgoff_t page_idx, int len)
>
> for (i = 0; i < page_len; i++, redirty_idx++) {
> page = find_lock_page(mapping, redirty_idx);
> - if (!page)
> + if (!page) {
> ret = -ENOENT;

ret = -ENOMEM;

> + continue;

How about breaking the loop for out-of-memory case, because in such condition
we have less chance to dirty whole cluster due to no memory, and continue to
allocate pages for target file will make system suffer more memory pressure,
it will make many thing slower.

Thnaks,

> + }
> set_page_dirty(page);
> f2fs_put_page(page, 1);
> f2fs_put_page(page, 0);
>

2021-01-05 02:13:19

by Daeho Jeong

Subject: Re: [f2fs-dev] [PATCH] f2fs: fix null page reference in redirty_blocks

Yes, it's better~ :)

2021년 1월 5일 (화) 오전 10:44, Chao Yu <[email protected]>님이 작성:
>
> On 2021/1/5 9:28, Daeho Jeong wrote:
> > From: Daeho Jeong <[email protected]>
> >
> > Fixed null page reference when find_lock_page() fails in
> > redirty_blocks().
> >
> > Signed-off-by: Daeho Jeong <[email protected]>
> > Reported-by: Colin Ian King <[email protected]>
> > Fixes: 5fdb322ff2c2 ("f2fs: add F2FS_IOC_DECOMPRESS_FILE and F2FS_IOC_COMPRESS_FILE")
> > ---
> > fs/f2fs/file.c | 4 +++-
> > 1 file changed, 3 insertions(+), 1 deletion(-)
> >
> > diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
> > index 9e5275716be8..bf6682a52433 100644
> > --- a/fs/f2fs/file.c
> > +++ b/fs/f2fs/file.c
> > @@ -4060,8 +4060,10 @@ static int redirty_blocks(struct inode *inode, pgoff_t page_idx, int len)
> >
> > for (i = 0; i < page_len; i++, redirty_idx++) {
> > page = find_lock_page(mapping, redirty_idx);
> > - if (!page)
> > + if (!page) {
> > ret = -ENOENT;
>
> ret = -ENOMEM;
>
> > + continue;
>
> How about breaking the loop for out-of-memory case, because in such condition
> we have less chance to dirty whole cluster due to no memory, and continue to
> allocate pages for target file will make system suffer more memory pressure,
> it will make many thing slower.
>
> Thnaks,
>
> > + }
> > set_page_dirty(page);
> > f2fs_put_page(page, 1);
> > f2fs_put_page(page, 0);
> >