Re: [f2fs-dev] [PATCH] mkfs.f2fs: support -C [no]hashonly to control linear lookup fallback

[Jaegeuk Kim via Linux-f2fs-devel <linux-f2fs-devel@lists.sourceforge.net>]

Can we disable linear lookup by default, but add an option to enable it?

On 07/24, Chao Yu wrote:
> It provides a way to disable linear lookup fallback during mkfs.
> 
> Usage:
> 
> 1. Disable linear lookup:
> mkfs.f2fs -f -O casefold -C utf8:hashonly /dev/vdb
> dump.f2fs -d3 /dev/vdb |grep s_encoding_flags
> s_encoding_flags                        [0x       2 : 2]
> 
> 2. Enable linear lookup:
> mkfs.f2fs -f -O casefold -C utf8:nohashonly /dev/vdb
> dump.f2fs -d3 /dev/vdb |grep s_encoding_flags
> s_encoding_flags                        [0x       0 : 0]
> 
> mkfs.f2fs -f -O casefold -C utf8 /dev/vdb
> dump.f2fs -d3 /dev/vdb |grep s_encoding_flags
> s_encoding_flags                        [0x       0 : 0]
> 
> Signed-off-by: Chao Yu <chao@kernel.org>
> ---
>  lib/libf2fs.c   | 1 +
>  man/mkfs.f2fs.8 | 8 +++++++-
>  2 files changed, 8 insertions(+), 1 deletion(-)
> 
> diff --git a/lib/libf2fs.c b/lib/libf2fs.c
> index 2f012c8..0e3e62a 100644
> --- a/lib/libf2fs.c
> +++ b/lib/libf2fs.c
> @@ -1424,6 +1424,7 @@ static const struct enc_flags {
>  	char *param;
>  } encoding_flags[] = {
>  	{ F2FS_ENC_STRICT_MODE_FL, "strict" },
> +	{ F2FS_ENC_NO_COMPAT_FALLBACK_FL, "hashonly"}
>  };
>  
>  /* Return a positive number < 0xff indicating the encoding magic number
> diff --git a/man/mkfs.f2fs.8 b/man/mkfs.f2fs.8
> index 8b3b0cc..b57f033 100644
> --- a/man/mkfs.f2fs.8
> +++ b/man/mkfs.f2fs.8
> @@ -232,10 +232,16 @@ Use UTF-8 for casefolding.
>  .I flags:
>  .RS 1.2i
>  .TP 1.2i
> -.B strict
> +.B [no]strict
>  This flag specifies that invalid strings should be rejected by the filesystem.
>  Default is disabled.
>  .RE
> +.RS 1.2i
> +.TP 1.2i
> +.B [no]hashonly
> +This flag specifies that there is no linear lookup fallback during lookup.
> +By default, linear lookup fallback is enabled.
> +.RE
>  .RE
>  .TP
>  .BI \-q
> -- 
> 2.49.0


_______________________________________________
Linux-f2fs-devel mailing list
Linux-f2fs-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel