On 7/25/2025 10:08 AM, Zhiguo Niu wrote:
Chao Yu via Linux-f2fs-devel <linux-f2fs-devel@lists.sourceforge.net> 于2025年7月25日周五 09:03写道：It provides a way to disable linear lookup fallback during mkfs. Behavior summary: Android Distro By default disabled enabled Tune w/ [no]hashonly no yes Android case: 1.1) Disable linear lookup: mkfs.f2fs -f -g android -O casefold -C utf8:hashonly /dev/vdb dump.f2fs -d3 /dev/vdb |grep s_encoding_flags s_encoding_flags [0x 2 : 2] 1.2) Enable linear lookup: mkfs.f2fs -f -g android -O casefold -C utf8:nohashonly /dev/vdb dump.f2fs -d3 /dev/vdb |grep s_encoding_flags s_encoding_flags [0x 2 : 2]Hi Chao, Seems like a typo here? should be:
Zhiguo, Not a typo, it's intentional, see above behavior summary. But after rethinking about this, I guess it will be good to honor 'nohashonly' for Android case like Distro case. Anyway, let me update the patch. Thanks,
s_encoding_flags [0x 0 : 0] ? thanks!1.3) By default: mkfs.f2fs -f -g android -O casefold -C utf8 /dev/vdb dump.f2fs -d3 /dev/vdb |grep s_encoding_flags s_encoding_flags [0x 2 : 2] Distro case: 2.1) 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] 2.2) 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] 2.3) By default: 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 <c...@kernel.org> --- v2: - disable linear lookup by default for Android case include/f2fs_fs.h | 3 ++- lib/libf2fs.c | 1 + man/mkfs.f2fs.8 | 10 ++++++++-- mkfs/f2fs_format.c | 3 +++ mkfs/f2fs_format_main.c | 3 ++- 5 files changed, 16 insertions(+), 4 deletions(-) diff --git a/include/f2fs_fs.h b/include/f2fs_fs.h index f7268d1..a8da8fa 100644 --- a/include/f2fs_fs.h +++ b/include/f2fs_fs.h @@ -1478,7 +1478,8 @@ enum { /* feature list in Android */ enum { - F2FS_FEATURE_NAT_BITS = 0x0001, + F2FS_FEATURE_NAT_BITS = 0x0001, + F2FS_FEATURE_LINEAR_LOOKUP = 0x0002, }; /* nolinear lookup tune */ 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..8cb7d32 100644 --- a/man/mkfs.f2fs.8 +++ b/man/mkfs.f2fs.8 @@ -232,9 +232,15 @@ 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. +For android case, it will disable linear lookup by default. +.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 diff --git a/mkfs/f2fs_format.c b/mkfs/f2fs_format.c index 2680bd3..a45bbcb 100644 --- a/mkfs/f2fs_format.c +++ b/mkfs/f2fs_format.c @@ -671,6 +671,9 @@ static int f2fs_prepare_super_block(void) memcpy(sb->init_version, c.version, VERSION_LEN); if (c.feature & F2FS_FEATURE_CASEFOLD) { + if (!(c.s_encoding_flags & F2FS_ENC_NO_COMPAT_FALLBACK_FL) && + (c.disabled_feature & F2FS_FEATURE_LINEAR_LOOKUP)) + c.s_encoding_flags |= F2FS_ENC_NO_COMPAT_FALLBACK_FL; set_sb(s_encoding, c.s_encoding); set_sb(s_encoding_flags, c.s_encoding_flags); } diff --git a/mkfs/f2fs_format_main.c b/mkfs/f2fs_format_main.c index f0bec4f..8f8e975 100644 --- a/mkfs/f2fs_format_main.c +++ b/mkfs/f2fs_format_main.c @@ -143,7 +143,8 @@ static void add_default_options(void) force_overwrite = 1; c.wanted_sector_size = F2FS_BLKSIZE; c.root_uid = c.root_gid = 0; - c.disabled_feature |= F2FS_FEATURE_NAT_BITS; + c.disabled_feature |= F2FS_FEATURE_NAT_BITS | + F2FS_FEATURE_LINEAR_LOOKUP; /* RO doesn't need any other features */ if (c.feature & F2FS_FEATURE_RO) -- 2.49.0 _______________________________________________ Linux-f2fs-devel mailing list Linux-f2fs-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
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