2024-03-22 06:04:29

by 牛志国 (Zhiguo Niu)

Subject: [PATCH] f2fs: fix to adjust appropirate defragment pg_end

A length that exceeds the real size of the inode may be
specified from user, although these out-of-range areas
are not mapped, but they still need to be check in
while loop, which is unnecessary.

Signed-off-by: Zhiguo Niu <[email protected]>
---
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 128e53d..0e7eac6 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -2609,7 +2609,9 @@ static int f2fs_defragment_range(struct f2fs_sb_info *sbi,
int err;

pg_start = range->start >> PAGE_SHIFT;
- pg_end = (range->start + range->len) >> PAGE_SHIFT;
+ pg_end = min_t(pgoff_t,
+ (range->start + range->len) >> PAGE_SHIFT,
+ DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE));

f2fs_balance_fs(sbi, true);

--
1.9.1

2024-03-23 03:02:22

by Chao Yu

Subject: Re: [PATCH] f2fs: fix to adjust appropirate defragment pg_end

On 2024/3/22 14:03, Zhiguo Niu wrote:
> A length that exceeds the real size of the inode may be
> specified from user, although these out-of-range areas
> are not mapped, but they still need to be check in
> while loop, which is unnecessary.
>
> Signed-off-by: Zhiguo Niu <[email protected]>
> ---
> 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 128e53d..0e7eac6 100644
> --- a/fs/f2fs/file.c
> +++ b/fs/f2fs/file.c
> @@ -2609,7 +2609,9 @@ static int f2fs_defragment_range(struct f2fs_sb_info *sbi,
> int err;
>
> pg_start = range->start >> PAGE_SHIFT;
> - pg_end = (range->start + range->len) >> PAGE_SHIFT;
> + pg_end = min_t(pgoff_t,
> + (range->start + range->len) >> PAGE_SHIFT,
> + DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE));

I guess we may check i_size w/ inode lock, it can avoid racing w/ append write
or truncate.

Thanks,

>
> f2fs_balance_fs(sbi, true);
>