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FROMGIT: f2fs: support to disable linear lookup fallback

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After commit 91b587ba79e1 ("f2fs: Introduce linear search for
dentries"), f2fs forced to use linear lookup whenever a hash-based
lookup fails on casefolded directory, it may affect performance for
scenarios: a) create a new file w/ filename it doesn't exist in
directory, b) lookup a file which may be removed.

This patch supports to disable linear lookup fallback, so, once there is
a solution for commit 5c26d2f1d3f5 ("unicode: Don't special case
ignorable code points") to fix red heart unicode issue, then we can set
an encodeing flag to disable the fallback for performance recovery.

The way is kept in line w/ ext4, refer to commit 9e28059d5664 ("ext4:
introduce linear search for dentries").

Bug: 410768629
(cherry picked from commit aa00c6d5d05a80ef5946984025c25ab231b722f9
https://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs.git dev)
Link: https://lore.kernel.org/linux-f2fs-devel/20250401035800.51504-1-chao@kernel.org
[Chao: backport dependent macro from commit 9e28059d5664 ("ext4:
introduce linear search for dentries")]
Cc: Daniel Lee <chullee@google.com>
Cc: Gabriel Krisman Bertazi <krisman@suse.de>
Change-Id: Idff994f832dcaa1b9a5eb750b8ae03a5e580c1c6
Signed-off-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Lee Jones <joneslee@google.com>
This commit is contained in:
Chao Yu
2025-04-01 11:58:00 +08:00
committed by Lee Jones
parent 7402843c3f
commit 229ec4d838
2 changed files with 11 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files

3
fs/f2fs/dir.c
View File

@@ -438,7 +438,8 @@ start_find_entry:
out:
#if IS_ENABLED(CONFIG_UNICODE)
if (IS_CASEFOLDED(dir) && !de && use_hash) {
if (!sb_no_casefold_compat_fallback(dir->i_sb) &&
IS_CASEFOLDED(dir) && !de && use_hash) {
use_hash = false;
goto start_find_entry;
}

10
include/linux/fs.h
View File

@@ -1409,11 +1409,19 @@ extern int send_sigurg(struct fown_struct *fown);
#define SB_NOUSER BIT(31)
/* These flags relate to encoding and casefolding */
#define SB_ENC_STRICT_MODE_FL (1 << 0)
#define SB_ENC_STRICT_MODE_FL (1 << 0)
#define SB_ENC_NO_COMPAT_FALLBACK_FL (1 << 1)
#define sb_has_strict_encoding(sb) \
(sb->s_encoding_flags & SB_ENC_STRICT_MODE_FL)
#if IS_ENABLED(CONFIG_UNICODE)
#define sb_no_casefold_compat_fallback(sb) \
(sb->s_encoding_flags & SB_ENC_NO_COMPAT_FALLBACK_FL)
#else
#define sb_no_casefold_compat_fallback(sb) (1)
#endif
/*
* Umount options
*/