* Re: [PATCH v2] f2fs: optimize f2fs_overwrite_io() for f2fs_iomap_begin
2026-01-22 10:45 ` [PATCH v2] f2fs: optimize f2fs_overwrite_io() for f2fs_iomap_begin Yeongjin Gil
@ 2026-01-23 4:07 ` Chao Yu
2026-02-10 21:28 ` [f2fs-dev] " patchwork-bot+f2fs
1 sibling, 0 replies; 3+ messages in thread
From: Chao Yu @ 2026-01-23 4:07 UTC (permalink / raw)
To: Yeongjin Gil, jaegeuk, jyh429, linux-f2fs-devel, linux-kernel
Cc: chao, Sungjong Seo, Sunmin Jeong
On 1/22/2026 6:45 PM, Yeongjin Gil wrote:
> When overwriting already allocated blocks, f2fs_iomap_begin() calls
> f2fs_overwrite_io() to check block mappings. However,
> f2fs_overwrite_io() iterates through all mapped blocks in the range,
> which can be inefficient for fragmented files with large I/O requests.
>
> This patch optimizes f2fs_overwrite_io() by adding a 'check_first'
> parameter and introducing __f2fs_overwrite_io() helper. When called from
> f2fs_iomap_begin(), we only check the first mapping to determine if the
> range is already allocated, which is sufficient for setting
> map.m_may_create.
>
> This optimization significantly reduces the number of f2fs_map_blocks()
> calls in f2fs_overwrite_io() when called from f2fs_iomap_begin(),
> especially for fragmented files with large I/O requests.
>
Cc: stable@kernel.org
> Fixes: 351bc761338d ("f2fs: optimize f2fs DIO overwrites")
> Reviewed-by: Sungjong Seo <sj1557.seo@samsung.com>
> Reviewed-by: Sunmin Jeong <s_min.jeong@samsung.com>
> Signed-off-by: Yeongjin Gil <youngjin.gil@samsung.com>
Otherwise, it looks good to me.
Reviewed-by: Chao Yu <chao@kernel.org>
Thanks,
> ---
> fs/f2fs/data.c | 12 ++++++++++--
> 1 file changed, 10 insertions(+), 2 deletions(-)
>
> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> index 2e133a723b99..11c262afad65 100644
> --- a/fs/f2fs/data.c
> +++ b/fs/f2fs/data.c
> @@ -1851,7 +1851,8 @@ int f2fs_map_blocks(struct inode *inode, struct f2fs_map_blocks *map, int flag)
> return err;
> }
>
> -bool f2fs_overwrite_io(struct inode *inode, loff_t pos, size_t len)
> +static bool __f2fs_overwrite_io(struct inode *inode, loff_t pos, size_t len,
> + bool check_first)
> {
> struct f2fs_map_blocks map;
> block_t last_lblk;
> @@ -1873,10 +1874,17 @@ bool f2fs_overwrite_io(struct inode *inode, loff_t pos, size_t len)
> if (err || map.m_len == 0)
> return false;
> map.m_lblk += map.m_len;
> + if (check_first)
> + break;
> }
> return true;
> }
>
> +bool f2fs_overwrite_io(struct inode *inode, loff_t pos, size_t len)
> +{
> + return __f2fs_overwrite_io(inode, pos, len, false);
> +}
> +
> static int f2fs_xattr_fiemap(struct inode *inode,
> struct fiemap_extent_info *fieinfo)
> {
> @@ -4443,7 +4451,7 @@ static int f2fs_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
> * f2fs_map_lock and f2fs_balance_fs are not necessary.
> */
> if ((flags & IOMAP_WRITE) &&
> - !f2fs_overwrite_io(inode, offset, length))
> + !__f2fs_overwrite_io(inode, offset, length, true))
> map.m_may_create = true;
>
> err = f2fs_map_blocks(inode, &map, F2FS_GET_BLOCK_DIO);
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [f2fs-dev] [PATCH v2] f2fs: optimize f2fs_overwrite_io() for f2fs_iomap_begin
2026-01-22 10:45 ` [PATCH v2] f2fs: optimize f2fs_overwrite_io() for f2fs_iomap_begin Yeongjin Gil
2026-01-23 4:07 ` Chao Yu
@ 2026-02-10 21:28 ` patchwork-bot+f2fs
1 sibling, 0 replies; 3+ messages in thread
From: patchwork-bot+f2fs @ 2026-02-10 21:28 UTC (permalink / raw)
To: Yeongjin Gil
Cc: jaegeuk, chao, jyh429, linux-f2fs-devel, linux-kernel, sj1557.seo
Hello:
This patch was applied to jaegeuk/f2fs.git (dev)
by Jaegeuk Kim <jaegeuk@kernel.org>:
On Thu, 22 Jan 2026 19:45:27 +0900 you wrote:
> When overwriting already allocated blocks, f2fs_iomap_begin() calls
> f2fs_overwrite_io() to check block mappings. However,
> f2fs_overwrite_io() iterates through all mapped blocks in the range,
> which can be inefficient for fragmented files with large I/O requests.
>
> This patch optimizes f2fs_overwrite_io() by adding a 'check_first'
> parameter and introducing __f2fs_overwrite_io() helper. When called from
> f2fs_iomap_begin(), we only check the first mapping to determine if the
> range is already allocated, which is sufficient for setting
> map.m_may_create.
>
> [...]
Here is the summary with links:
- [f2fs-dev,v2] f2fs: optimize f2fs_overwrite_io() for f2fs_iomap_begin
https://git.kernel.org/jaegeuk/f2fs/c/d860974a7e38
You are awesome, thank you!
--
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^ permalink raw reply [flat|nested] 3+ messages in thread