From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from dggsgout11.his.huawei.com (dggsgout11.his.huawei.com [45.249.212.51]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 81D093328EF; Tue, 11 Nov 2025 14:35:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.51 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762871737; cv=none; b=feJY/gaF6NY6v54wsLaz3SaZgwPUFjfWzOpqCEJGpO08irCSUUdKjymdwHiNxuWpB7ORGiZ9dZ81QMiW096XUlSjPt3azIFEKWvd/cBqXs89ho+kty4CNk4sfNbFXLON2hHNTteWapZK9OxK6wEI7FS10DglRBN3kidSUqU80es= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762871737; c=relaxed/simple; bh=zru6h0tSducD5Q4JGP0Z7AO61CNXM4NKMumOKOKELBk=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=rxNsw/90O2oQf3X9nIAF1cJvMKlpFFtZ7sKZxLqFBI14cQERih6gJ/SYMTLqBx/G0HlM3FPtgb25jb43KgB4JswCBxAuIj2DBWKA7rRTJtzLS562psehHoGfAmtD8ijwXUcdGFuuwSG2XzhPq1+MmOwbajhPfy4ZELUN4z7INa8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=huaweicloud.com; spf=pass smtp.mailfrom=huaweicloud.com; arc=none smtp.client-ip=45.249.212.51 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=huaweicloud.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huaweicloud.com Received: from mail.maildlp.com (unknown [172.19.163.216]) by dggsgout11.his.huawei.com (SkyGuard) with ESMTPS id 4d5TZr6BpLzYQv27; Tue, 11 Nov 2025 22:35:00 +0800 (CST) Received: from mail02.huawei.com (unknown [10.116.40.75]) by mail.maildlp.com (Postfix) with ESMTP id B51921A19A0; Tue, 11 Nov 2025 22:35:27 +0800 (CST) Received: from huaweicloud.com (unknown [10.50.87.129]) by APP2 (Coremail) with SMTP id Syh0CgBHo3mrSRNpgYWKAQ--.32556S16; Tue, 11 Nov 2025 22:35:27 +0800 (CST) From: libaokun@huaweicloud.com To: linux-ext4@vger.kernel.org Cc: tytso@mit.edu, adilger.kernel@dilger.ca, jack@suse.cz, linux-kernel@vger.kernel.org, kernel@pankajraghav.com, mcgrof@kernel.org, ebiggers@kernel.org, willy@infradead.org, yi.zhang@huawei.com, yangerkun@huawei.com, chengzhihao1@huawei.com, libaokun1@huawei.com, libaokun@huaweicloud.com Subject: [PATCH v3 12/24] ext4: support large block size in ext4_mb_get_buddy_page_lock() Date: Tue, 11 Nov 2025 22:26:22 +0800 Message-Id: <20251111142634.3301616-13-libaokun@huaweicloud.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20251111142634.3301616-1-libaokun@huaweicloud.com> References: <20251111142634.3301616-1-libaokun@huaweicloud.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-CM-TRANSID:Syh0CgBHo3mrSRNpgYWKAQ--.32556S16 X-Coremail-Antispam: 1UD129KBjvJXoWxJF13CF47GF4xuFyDGF1rWFg_yoWrZF48pa y7Cwn8Jr4kWasrursrZ3saq3WFkas5Zay7A3yIgr13uFy3J34IkFy0k3WUXF1UtFWxGFs5 XF45Zry3WF1UX3DanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUQa14x267AKxVWrJVCq3wAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2048vs2IY020E87I2jVAFwI0_JF0E3s1l82xGYI kIc2x26xkF7I0E14v26ryj6s0DM28lY4IEw2IIxxk0rwA2F7IY1VAKz4vEj48ve4kI8wA2 z4x0Y4vE2Ix0cI8IcVAFwI0_tr0E3s1l84ACjcxK6xIIjxv20xvEc7CjxVAFwI0_Gr1j6F 4UJwA2z4x0Y4vEx4A2jsIE14v26rxl6s0DM28EF7xvwVC2z280aVCY1x0267AKxVW0oVCq 3wAS0I0E0xvYzxvE52x082IY62kv0487Mc02F40EFcxC0VAKzVAqx4xG6I80ewAv7VC0I7 IYx2IY67AKxVWUXVWUAwAv7VC2z280aVAFwI0_Gr1j6F4UJwAm72CE4IkC6x0Yz7v_Jr0_ Gr1lF7xvr2IYc2Ij64vIr41lF7I21c0EjII2zVCS5cI20VAGYxC7M4IIrI8v6xkF7I0E8c xan2IY04v7M4kE6xkIj40Ew7xC0wCY1x0262kKe7AKxVWUtVW8ZwCF04k20xvY0x0EwIxG rwCFx2IqxVCFs4IE7xkEbVWUJVW8JwC20s026c02F40E14v26r1j6r18MI8I3I0E7480Y4 vE14v26r106r1rMI8E67AF67kF1VAFwI0_Jw0_GFylIxkGc2Ij64vIr41lIxAIcVC0I7IY x2IY67AKxVW8JVW5JwCI42IY6xIIjxv20xvEc7CjxVAFwI0_Gr1j6F4UJwCI42IY6xAIw2 0EY4v20xvaj40_Jr0_JF4lIxAIcVC2z280aVAFwI0_Gr0_Cr1lIxAIcVC2z280aVCY1x02 67AKxVW8Jr0_Cr1UYxBIdaVFxhVjvjDU0xZFpf9x0JUdsqAUUUUU= X-CM-SenderInfo: 5olet0hnxqqx5xdzvxpfor3voofrz/1tbiAgAJBWkSsIpDTQAAsB From: Baokun Li Currently, ext4_mb_get_buddy_page_lock() uses blocks_per_page to calculate folio index and offset. However, when blocksize is larger than PAGE_SIZE, blocks_per_page becomes zero, leading to a potential division-by-zero bug. To support BS > PS, use bytes to compute folio index and offset within folio to get rid of blocks_per_page. Also, since ext4_mb_get_buddy_page_lock() already fully supports folio, rename it to ext4_mb_get_buddy_folio_lock(). Signed-off-by: Baokun Li Reviewed-by: Zhang Yi Reviewed-by: Jan Kara --- fs/ext4/mballoc.c | 42 ++++++++++++++++++++++-------------------- 1 file changed, 22 insertions(+), 20 deletions(-) diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c index 143d6ff1fdef..b454a41dd6c1 100644 --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -1510,50 +1510,52 @@ static int ext4_mb_init_cache(struct folio *folio, char *incore, gfp_t gfp) } /* - * Lock the buddy and bitmap pages. This make sure other parallel init_group - * on the same buddy page doesn't happen whild holding the buddy page lock. - * Return locked buddy and bitmap pages on e4b struct. If buddy and bitmap - * are on the same page e4b->bd_buddy_folio is NULL and return value is 0. + * Lock the buddy and bitmap folios. This makes sure other parallel init_group + * on the same buddy folio doesn't happen while holding the buddy folio lock. + * Return locked buddy and bitmap folios on e4b struct. If buddy and bitmap + * are on the same folio e4b->bd_buddy_folio is NULL and return value is 0. */ -static int ext4_mb_get_buddy_page_lock(struct super_block *sb, +static int ext4_mb_get_buddy_folio_lock(struct super_block *sb, ext4_group_t group, struct ext4_buddy *e4b, gfp_t gfp) { struct inode *inode = EXT4_SB(sb)->s_buddy_cache; - int block, pnum, poff; - int blocks_per_page; + int block, pnum; struct folio *folio; e4b->bd_buddy_folio = NULL; e4b->bd_bitmap_folio = NULL; - blocks_per_page = PAGE_SIZE / sb->s_blocksize; /* * the buddy cache inode stores the block bitmap * and buddy information in consecutive blocks. * So for each group we need two blocks. */ block = group * 2; - pnum = block / blocks_per_page; - poff = block % blocks_per_page; + pnum = EXT4_LBLK_TO_PG(inode, block); folio = __filemap_get_folio(inode->i_mapping, pnum, FGP_LOCK | FGP_ACCESSED | FGP_CREAT, gfp); if (IS_ERR(folio)) return PTR_ERR(folio); BUG_ON(folio->mapping != inode->i_mapping); + WARN_ON_ONCE(folio_size(folio) < sb->s_blocksize); e4b->bd_bitmap_folio = folio; - e4b->bd_bitmap = folio_address(folio) + (poff * sb->s_blocksize); + e4b->bd_bitmap = folio_address(folio) + + offset_in_folio(folio, EXT4_LBLK_TO_B(inode, block)); - if (blocks_per_page >= 2) { - /* buddy and bitmap are on the same page */ + block++; + pnum = EXT4_LBLK_TO_PG(inode, block); + if (folio_contains(folio, pnum)) { + /* buddy and bitmap are on the same folio */ return 0; } - /* blocks_per_page == 1, hence we need another page for the buddy */ - folio = __filemap_get_folio(inode->i_mapping, block + 1, + /* we need another folio for the buddy */ + folio = __filemap_get_folio(inode->i_mapping, pnum, FGP_LOCK | FGP_ACCESSED | FGP_CREAT, gfp); if (IS_ERR(folio)) return PTR_ERR(folio); BUG_ON(folio->mapping != inode->i_mapping); + WARN_ON_ONCE(folio_size(folio) < sb->s_blocksize); e4b->bd_buddy_folio = folio; return 0; } @@ -1592,14 +1594,14 @@ int ext4_mb_init_group(struct super_block *sb, ext4_group_t group, gfp_t gfp) /* * This ensures that we don't reinit the buddy cache - * page which map to the group from which we are already + * folio which map to the group from which we are already * allocating. If we are looking at the buddy cache we would * have taken a reference using ext4_mb_load_buddy and that - * would have pinned buddy page to page cache. - * The call to ext4_mb_get_buddy_page_lock will mark the - * page accessed. + * would have pinned buddy folio to page cache. + * The call to ext4_mb_get_buddy_folio_lock will mark the + * folio accessed. */ - ret = ext4_mb_get_buddy_page_lock(sb, group, &e4b, gfp); + ret = ext4_mb_get_buddy_folio_lock(sb, group, &e4b, gfp); if (ret || !EXT4_MB_GRP_NEED_INIT(this_grp)) { /* * somebody initialized the group -- 2.46.1