{"id":2234985,"url":"http://patchwork.ozlabs.org/api/1.2/patches/2234985/?format=json","web_url":"http://patchwork.ozlabs.org/project/linux-ext4/patch/20260508121539.4174601-10-libaokun@linux.alibaba.com/","project":{"id":8,"url":"http://patchwork.ozlabs.org/api/1.2/projects/8/?format=json","name":"Linux ext4 filesystem development","link_name":"linux-ext4","list_id":"linux-ext4.vger.kernel.org","list_email":"linux-ext4@vger.kernel.org","web_url":null,"scm_url":null,"webscm_url":null,"list_archive_url":"","list_archive_url_format":"","commit_url_format":""},"msgid":"<20260508121539.4174601-10-libaokun@linux.alibaba.com>","list_archive_url":null,"date":"2026-05-08T12:15:31","name":"[RFC,09/17] ext4: add ext4_inode_bitmap_csum_set_fast() for incremental checksum update","commit_ref":null,"pull_url":null,"state":"new","archived":false,"hash":"7aaeab1678834d1e9a3b4cfd85a29d3847612da9","submitter":{"id":92757,"url":"http://patchwork.ozlabs.org/api/1.2/people/92757/?format=json","name":"Baokun Li","email":"libaokun@linux.alibaba.com"},"delegate":null,"mbox":"http://patchwork.ozlabs.org/project/linux-ext4/patch/20260508121539.4174601-10-libaokun@linux.alibaba.com/mbox/","series":[{"id":503377,"url":"http://patchwork.ozlabs.org/api/1.2/series/503377/?format=json","web_url":"http://patchwork.ozlabs.org/project/linux-ext4/list/?series=503377","date":"2026-05-08T12:15:22","name":"ext4/lib-crc: LBS performance part 1 - incremental CRC32c for bitmap checksums","version":1,"mbox":"http://patchwork.ozlabs.org/series/503377/mbox/"}],"comments":"http://patchwork.ozlabs.org/api/patches/2234985/comments/","check":"pending","checks":"http://patchwork.ozlabs.org/api/patches/2234985/checks/","tags":{},"related":[],"headers":{"Return-Path":"\n ","X-Original-To":["incoming@patchwork.ozlabs.org","linux-ext4@vger.kernel.org"],"Delivered-To":["patchwork-incoming@legolas.ozlabs.org","patchwork-incoming@ozlabs.org"],"Authentication-Results":["legolas.ozlabs.org;\n\tdkim=pass (1024-bit key;\n unprotected) header.d=linux.alibaba.com header.i=@linux.alibaba.com\n header.a=rsa-sha256 header.s=default header.b=h/rfQxVC;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=ozlabs.org\n (client-ip=150.107.74.76; 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a=rsa-sha256; c=relaxed/relaxed;\n\td=linux.alibaba.com; s=default;\n\tt=1778242567; h=From:To:Subject:Date:Message-ID:MIME-Version;\n\tbh=FozibAPcd218Q8rcuEIXF/fsaz9qBa8qxrGVF06VcRg=;\n\tb=h/rfQxVCQxhXweJBzmX6naUKUhljs3DG0vCRLrXDPsFS0Ptrm0O8MkuBsLv6a9sjgVahRbTdugh6uaHha3UcEMnXT1HW4n3VHq/DaU+2lACj5/XLAq59qgKbVZxitTSOa9paVW8oK7GTu/3LrO5HOKtQWIp2jXbIO4OTR6VwyYo=","X-Alimail-AntiSpam":"\n AC=PASS;BC=-1|-1;BR=01201311R541e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=maildocker-contentspam033032089153;MF=libaokun@linux.alibaba.com;NM=1;PH=DS;RN=11;SR=0;TI=SMTPD_---0X2XQgq5_1778242566;","From":"Baokun Li ","To":"linux-ext4@vger.kernel.org","Cc":"linux-crypto@vger.kernel.org,\n\tebiggers@kernel.org,\n\tardb@kernel.org,\n\ttytso@mit.edu,\n\tadilger.kernel@dilger.ca,\n\tjack@suse.cz,\n\tyi.zhang@huawei.com,\n\tojaswin@linux.ibm.com,\n\tritesh.list@gmail.com,\n\tBaokun Li ","Subject":"[PATCH RFC 09/17] ext4: add ext4_inode_bitmap_csum_set_fast() for\n incremental checksum update","Date":"Fri, 8 May 2026 20:15:31 +0800","Message-ID":"<20260508121539.4174601-10-libaokun@linux.alibaba.com>","X-Mailer":"git-send-email 2.43.7","In-Reply-To":"<20260508121539.4174601-1-libaokun@linux.alibaba.com>","References":"<20260508121539.4174601-1-libaokun@linux.alibaba.com>","Precedence":"bulk","X-Mailing-List":"linux-ext4@vger.kernel.org","List-Id":"","List-Subscribe":"","List-Unsubscribe":"","MIME-Version":"1.0","Content-Transfer-Encoding":"8bit","X-Spam-Status":"No, score=-8.7 required=5.0 tests=ARC_SIGNED,ARC_VALID,\n\tDKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DMARC_PASS,\n\tHEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,\n\tSPF_PASS,UNPARSEABLE_RELAY,USER_IN_DEF_DKIM_WL autolearn=disabled\n\tversion=4.0.1","X-Spam-Checker-Version":"SpamAssassin 4.0.1 (2024-03-25) on gandalf.ozlabs.org"},"content":"Add a helper function ext4_inode_bitmap_csum_set_fast() that uses\ncrc32c_flip_range() to incrementally update the inode bitmap checksum\nafter flipping a single bit at the given offset. This avoids a full\nbitmap CRC rescan, computing the CRC delta in O(log N) time.\n\nSigned-off-by: Baokun Li \n---\n fs/ext4/bitmap.c | 23 +++++++++++++++++++++++\n fs/ext4/ext4.h | 3 +++\n 2 files changed, 26 insertions(+)","diff":"diff --git a/fs/ext4/bitmap.c b/fs/ext4/bitmap.c\nindex 008acc439301..ea47ca0d7046 100644\n--- a/fs/ext4/bitmap.c\n+++ b/fs/ext4/bitmap.c\n@@ -71,6 +71,29 @@ void ext4_inode_bitmap_csum_set(struct super_block *sb,\n \text4_inode_bitmap_csum_store(sb, gdp, csum);\n }\n \n+/*\n+ * Update inode bitmap checksum for a single flipped bit.\n+ *\n+ * Use crc32c_flip_range() to incrementally update the checksum after\n+ * flipping the bit at @offset, avoiding a full bitmap CRC rescan.\n+ * The csum_seed cancels out in the XOR delta, so it is not needed here.\n+ */\n+void ext4_inode_bitmap_csum_set_fast(struct super_block *sb,\n+\t\t\t\t struct ext4_group_desc *gdp,\n+\t\t\t\t ext4_grpblk_t offset)\n+{\n+\t__u32 new_csum, old_csum;\n+\n+\tif (!ext4_has_feature_metadata_csum(sb))\n+\t\treturn;\n+\n+\told_csum = ext4_inode_bitmap_csum_get(sb, gdp);\n+\tnew_csum = crc32c_flip_range(old_csum, EXT4_INODES_PER_GROUP(sb),\n+\t\t\t\t offset, 1);\n+\n+\text4_inode_bitmap_csum_store(sb, gdp, new_csum);\n+}\n+\n static inline __u32 ext4_block_bitmap_csum_get(struct super_block *sb,\n \t\t\t\t\t struct ext4_group_desc *gdp)\n {\ndiff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h\nindex c423a9a04047..e6739d5af490 100644\n--- a/fs/ext4/ext4.h\n+++ b/fs/ext4/ext4.h\n@@ -2764,6 +2764,9 @@ extern unsigned int ext4_count_free(char *bitmap, unsigned numchars);\n void ext4_inode_bitmap_csum_set(struct super_block *sb,\n \t\t\t\tstruct ext4_group_desc *gdp,\n \t\t\t\tstruct buffer_head *bh);\n+void ext4_inode_bitmap_csum_set_fast(struct super_block *sb,\n+\t\t\t\t struct ext4_group_desc *gdp,\n+\t\t\t\t ext4_grpblk_t offset);\n int ext4_inode_bitmap_csum_verify(struct super_block *sb,\n \t\t\t\t struct ext4_group_desc *gdp,\n \t\t\t\t struct buffer_head *bh);\n","prefixes":["RFC","09/17"]}