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Message-Id: <20230621083209.116024-3-jefflexu@linux.alibaba.com>
Date: Wed, 21 Jun 2023 16:32:09 +0800
From: Jingbo Xu <jefflexu@...ux.alibaba.com>
To: hsiangkao@...ux.alibaba.com, chao@...nel.org, huyue2@...lpad.com,
linux-erofs@...ts.ozlabs.org
Cc: linux-kernel@...r.kernel.org, alexl@...hat.com
Subject: [RFC 2/2] erofs: optimize getxattr with bloom filter
Boost the negative xattr lookup with bloom filter.
The bit value for the bloom filter map has a reverse semantics for
compatibility. That is, the mapped bits will be cleared to 0, while the
bit value of 1 indicates the absence of corresponding xattr.
Signed-off-by: Jingbo Xu <jefflexu@...ux.alibaba.com>
---
fs/erofs/internal.h | 2 ++
fs/erofs/xattr.c | 16 +++++++++++++++-
2 files changed, 17 insertions(+), 1 deletion(-)
diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
index 1e39c03357d1..49b4b350af8a 100644
--- a/fs/erofs/internal.h
+++ b/fs/erofs/internal.h
@@ -285,6 +285,7 @@ EROFS_FEATURE_FUNCS(fragments, incompat, INCOMPAT_FRAGMENTS)
EROFS_FEATURE_FUNCS(dedupe, incompat, INCOMPAT_DEDUPE)
EROFS_FEATURE_FUNCS(xattr_prefixes, incompat, INCOMPAT_XATTR_PREFIXES)
EROFS_FEATURE_FUNCS(sb_chksum, compat, COMPAT_SB_CHKSUM)
+EROFS_FEATURE_FUNCS(xattr_bloom, compat, COMPAT_XATTR_BLOOM)
/* atomic flag definitions */
#define EROFS_I_EA_INITED_BIT 0
@@ -304,6 +305,7 @@ struct erofs_inode {
unsigned char inode_isize;
unsigned int xattr_isize;
+ unsigned long xattr_bloom_map;
unsigned int xattr_shared_count;
unsigned int *xattr_shared_xattrs;
diff --git a/fs/erofs/xattr.c b/fs/erofs/xattr.c
index 4376f654474d..1ab481b46e8d 100644
--- a/fs/erofs/xattr.c
+++ b/fs/erofs/xattr.c
@@ -5,6 +5,7 @@
* Copyright (C) 2021-2022, Alibaba Cloud
*/
#include <linux/security.h>
+#include <linux/xxhash.h>
#include "xattr.h"
struct erofs_xattr_iter {
@@ -87,6 +88,7 @@ static int erofs_init_inode_xattrs(struct inode *inode)
}
ih = it.kaddr + erofs_blkoff(sb, it.pos);
+ vi->xattr_bloom_map = le32_to_cpu(ih->h_map);
vi->xattr_shared_count = ih->h_shared_count;
vi->xattr_shared_xattrs = kmalloc_array(vi->xattr_shared_count,
sizeof(uint), GFP_KERNEL);
@@ -392,8 +394,11 @@ int erofs_getxattr(struct inode *inode, int index,
const char *name,
void *buffer, size_t buffer_size)
{
- int ret;
+ int i, ret;
+ uint32_t bit;
struct erofs_xattr_iter it;
+ struct erofs_inode *const vi = EROFS_I(inode);
+ struct erofs_sb_info *sbi = EROFS_SB(inode->i_sb);
if (!name)
return -EINVAL;
@@ -402,6 +407,15 @@ int erofs_getxattr(struct inode *inode, int index,
if (ret)
return ret;
+ if (erofs_sb_has_xattr_bloom(sbi) && vi->xattr_bloom_map) {
+ for (i = 0; i < EROFS_XATTR_BLOOM_COUNTS; i++) {
+ bit = xxh32(name, strlen(name), index + i);
+ bit &= EROFS_XATTR_BLOOM_MASK;
+ if (test_bit(bit, &vi->xattr_bloom_map))
+ return -ENOATTR;
+ }
+ }
+
it.index = index;
it.name = (struct qstr)QSTR_INIT(name, strlen(name));
if (it.name.len > EROFS_NAME_LEN)
--
2.19.1.6.gb485710b
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