Hi Jaegeuk,
On Fri, Jul 25, 2014 at 03:47:21PM -0700, Jaegeuk Kim wrote:
> This patch enforces in-place-updates only when fdatasync is requested.
> If we adopt this in-place-updates for the fdatasync, we can skip to write the
> recovery information.
But, as you know, random write occurs when changing into in-place-updates.
It will degrade write performance. Is there any case in-place-updates is
better, except recovery or high utilization?
Thanks
>
> Signed-off-by: Jaegeuk Kim <jaegeuk@xxxxxxxxxx>
> ---
> fs/f2fs/f2fs.h | 1 +
> fs/f2fs/file.c | 7 +++++++
> fs/f2fs/segment.h | 4 ++++
> 3 files changed, 12 insertions(+)
>
> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> index ab36025..8f8685e 100644
> --- a/fs/f2fs/f2fs.h
> +++ b/fs/f2fs/f2fs.h
> @@ -998,6 +998,7 @@ enum {
> FI_INLINE_DATA, /* used for inline data*/
> FI_APPEND_WRITE, /* inode has appended data */
> FI_UPDATE_WRITE, /* inode has in-place-update data */
> + FI_NEED_IPU, /* used fo ipu for fdatasync */
> };
>
> static inline void set_inode_flag(struct f2fs_inode_info *fi, int flag)
> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
> index 121689a..e339856 100644
> --- a/fs/f2fs/file.c
> +++ b/fs/f2fs/file.c
> @@ -127,11 +127,18 @@ int f2fs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
> return 0;
>
> trace_f2fs_sync_file_enter(inode);
> +
> + /* if fdatasync is triggered, let's do in-place-update */
> + if (datasync)
> + set_inode_flag(fi, FI_NEED_IPU);
> +
> ret = filemap_write_and_wait_range(inode->i_mapping, start, end);
> if (ret) {
> trace_f2fs_sync_file_exit(inode, need_cp, datasync, ret);
> return ret;
> }
> + if (datasync)
> + clear_inode_flag(fi, FI_NEED_IPU);
>
> /*
> * if there is no written data, don't waste time to write recovery info.
> diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h
> index ee5c75e..55973f7 100644
> --- a/fs/f2fs/segment.h
> +++ b/fs/f2fs/segment.h
> @@ -486,6 +486,10 @@ static inline bool need_inplace_update(struct inode *inode)
> if (S_ISDIR(inode->i_mode))
> return false;
>
> + /* this is only set during fdatasync */
> + if (is_inode_flag_set(F2FS_I(inode), FI_NEED_IPU))
> + return true;
> +
> switch (SM_I(sbi)->ipu_policy) {
> case F2FS_IPU_FORCE:
> return true;
> --
> 1.8.5.2 (Apple Git-48)
>
>
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