From nobody Mon Feb 9 16:16:52 2026 Received: from dggsgout12.his.huawei.com (dggsgout12.his.huawei.com [45.249.212.56]) (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 3639F387598; Tue, 3 Feb 2026 06:30:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.56 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770100224; cv=none; b=e2IpeC6CIploSigJ2Ty+j2IEPENeYpF87CELZ0VBqIQIUvcSqniiCElkGVFvjTUdv2Y4TuoI8oVgY14xPdfKCf79w2Tlk5HIiVozxqg1Gz2+DvnIpaZQkVLeFgG3ZCGyZKip77Nfe5atoajn9h01cBhJf847xViAPl/sb2QN4UM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770100224; c=relaxed/simple; bh=gqkcO0uUZ+Eq+shjRmDg5PzjBHQRmoKJo8G4i9A8gEE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Jxa7ACX5G7JLou+ZJ2IVbCYucHN5UGcFVfgz9rYsKTSy0G5RTidsHwpROI+I/wBdamBKHEtK5ZZprq/GnXR+JtBEGhcsrrS6XGypg6VSWu2OvdFPCwz3SdIfiM7nq+RZ1LNOKcTIlBzes5INy3Lypy6ZjOLaeh9ZVid8RyAOGFk= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=huawei.com; spf=none smtp.mailfrom=huaweicloud.com; arc=none smtp.client-ip=45.249.212.56 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=huaweicloud.com Received: from mail.maildlp.com (unknown [172.19.163.170]) by dggsgout12.his.huawei.com (SkyGuard) with ESMTPS id 4f4trK5m7ZzKHMcM; Tue, 3 Feb 2026 14:29:53 +0800 (CST) Received: from mail02.huawei.com (unknown [10.116.40.128]) by mail.maildlp.com (Postfix) with ESMTP id 1F0AF4056B; Tue, 3 Feb 2026 14:30:15 +0800 (CST) Received: from huaweicloud.com (unknown [10.50.85.155]) by APP4 (Coremail) with SMTP id gCh0CgAHaPjnlYFpiadbGA--.27803S21; Tue, 03 Feb 2026 14:30:14 +0800 (CST) From: Zhang Yi To: linux-ext4@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, tytso@mit.edu, adilger.kernel@dilger.ca, jack@suse.cz, ojaswin@linux.ibm.com, ritesh.list@gmail.com, hch@infradead.org, djwong@kernel.org, yi.zhang@huawei.com, yi.zhang@huaweicloud.com, yizhang089@gmail.com, libaokun1@huawei.com, yangerkun@huawei.com, yukuai@fnnas.com Subject: [PATCH -next v2 17/22] ext4: implement partial block zero range iomap path Date: Tue, 3 Feb 2026 14:25:17 +0800 Message-ID: <20260203062523.3869120-18-yi.zhang@huawei.com> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20260203062523.3869120-1-yi.zhang@huawei.com> References: <20260203062523.3869120-1-yi.zhang@huawei.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-CM-TRANSID: gCh0CgAHaPjnlYFpiadbGA--.27803S21 X-Coremail-Antispam: 1UD129KBjvJXoWxAw1xAr1rZryUArWfWw48WFg_yoWrtw43pr WDKrW5Gr47Xr9Igr4ftFsrXr1Yk3WxKrW8Wry3Grn8Z3s0q34xKa18KFyak3W5tw47Cw4j qF4jyr1xKF1UArDanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUHqb4IE77IF4wAFF20E14v26rWj6s0DM7CY07I20VC2zVCF04k2 6cxKx2IYs7xG6rWj6s0DM7CIcVAFz4kK6r1j6r18M28IrcIa0xkI8VA2jI8067AKxVWUAV Cq3wA2048vs2IY020Ec7CjxVAFwI0_Xr0E3s1l8cAvFVAK0II2c7xJM28CjxkF64kEwVA0 rcxSw2x7M28EF7xvwVC0I7IYx2IY67AKxVWDJVCq3wA2z4x0Y4vE2Ix0cI8IcVCY1x0267 AKxVW8Jr0_Cr1UM28EF7xvwVC2z280aVAFwI0_GcCE3s1l84ACjcxK6I8E87Iv6xkF7I0E 14v26rxl6s0DM2AIxVAIcxkEcVAq07x20xvEncxIr21l5I8CrVACY4xI64kE6c02F40Ex7 xfMcIj6xIIjxv20xvE14v26r1j6r18McIj6I8E87Iv67AKxVWUJVW8JwAm72CE4IkC6x0Y z7v_Jr0_Gr1lF7xvr2IYc2Ij64vIr41lF7Iv64x0x7Aq67IIx4CEVc8vx2IErcIFxwACI4 02YVCY1x02628vn2kIc2xKxwCY1x0262kKe7AKxVWUtVW8ZwCF04k20xvY0x0EwIxGrwCF 04k20xvEw4C26cxK6c8Ij28IcwCFx2IqxVCFs4IE7xkEbVWUJVW8JwC20s026c02F40E14 v26r1j6r18MI8I3I0E7480Y4vE14v26r106r1rMI8E67AF67kF1VAFwI0_GFv_WrylIxkG c2Ij64vIr41lIxAIcVC0I7IYx2IY67AKxVW8JVW5JwCI42IY6xIIjxv20xvEc7CjxVAFwI 0_Gr1j6F4UJwCI42IY6xAIw20EY4v20xvaj40_Jr0_JF4lIxAIcVC2z280aVAFwI0_Gr0_ Cr1lIxAIcVC2z280aVCY1x0267AKxVW8Jr0_Cr1UYxBIdaVFxhVjvjDU0xZFpf9x07UZyC LUUUUU= Sender: yi.zhang@huaweicloud.com X-CM-SenderInfo: d1lo6xhdqjqx5xdzvxpfor3voofrz/ Content-Type: text/plain; charset="utf-8" Introduce a new iomap_ops instance, ext4_iomap_zero_ops, along with ext4_iomap_block_zero_range() to implement the iomap block zeroing range for ext4. ext4_iomap_block_zero_range() invokes iomap_zero_range() and passes ext4_iomap_zero_begin() to locate and zero out a mapped partial block or a dirty, unwritten partial block. Note that zeroing out under an active handle can cause deadlock since the order of acquiring the folio lock and starting a handle is inconsistent with the iomap iteration procedure. Therefore, ext4_iomap_block_zero_range() cannot be called under an active handle. Signed-off-by: Zhang Yi --- fs/ext4/inode.c | 85 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 85 insertions(+) diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 0d2852159fa3..c59f3adba0f3 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -4107,6 +4107,50 @@ static int ext4_iomap_buffered_da_write_end(struct i= node *inode, loff_t offset, return 0; } =20 +static int ext4_iomap_zero_begin(struct inode *inode, + loff_t offset, loff_t length, unsigned int flags, + struct iomap *iomap, struct iomap *srcmap) +{ + struct iomap_iter *iter =3D container_of(iomap, struct iomap_iter, iomap); + struct ext4_map_blocks map; + u8 blkbits =3D inode->i_blkbits; + unsigned int iomap_flags =3D 0; + int ret; + + ret =3D ext4_emergency_state(inode->i_sb); + if (unlikely(ret)) + return ret; + + if (WARN_ON_ONCE(!(flags & IOMAP_ZERO))) + return -EINVAL; + + ret =3D ext4_iomap_map_blocks(inode, offset, length, NULL, &map); + if (ret < 0) + return ret; + + /* + * Look up dirty folios for unwritten mappings within EOF. Providing + * this bypasses the flush iomap uses to trigger extent conversion + * when unwritten mappings have dirty pagecache in need of zeroing. + */ + if (map.m_flags & EXT4_MAP_UNWRITTEN) { + loff_t offset =3D ((loff_t)map.m_lblk) << blkbits; + loff_t end =3D ((loff_t)map.m_lblk + map.m_len) << blkbits; + + iomap_fill_dirty_folios(iter, &offset, end, &iomap_flags); + if ((offset >> blkbits) < map.m_lblk + map.m_len) + map.m_len =3D (offset >> blkbits) - map.m_lblk; + } + + ext4_set_iomap(inode, iomap, &map, offset, length, flags); + iomap->flags |=3D iomap_flags; + + return 0; +} + +const struct iomap_ops ext4_iomap_zero_ops =3D { + .iomap_begin =3D ext4_iomap_zero_begin, +}; =20 const struct iomap_ops ext4_iomap_buffered_write_ops =3D { .iomap_begin =3D ext4_iomap_buffered_write_begin, @@ -4622,6 +4666,32 @@ static int ext4_journalled_block_zero_range(struct i= node *inode, loff_t from, return err; } =20 +static int ext4_iomap_block_zero_range(struct inode *inode, loff_t from, + loff_t length, bool *did_zero) +{ + /* + * Zeroing out under an active handle can cause deadlock since + * the order of acquiring the folio lock and starting a handle is + * inconsistent with the iomap writeback procedure. + */ + if (WARN_ON_ONCE(ext4_handle_valid(journal_current_handle()))) + return -EINVAL; + + /* The zeroing scope should not extend across a block. */ + if (WARN_ON_ONCE((from >> inode->i_blkbits) !=3D + ((from + length - 1) >> inode->i_blkbits))) + return -EINVAL; + + if (!(EXT4_SB(inode->i_sb)->s_mount_state & EXT4_ORPHAN_FS) && + !(inode_state_read_once(inode) & (I_NEW | I_FREEING))) + WARN_ON_ONCE(!inode_is_locked(inode) && + !rwsem_is_locked(&inode->i_mapping->invalidate_lock)); + + return iomap_zero_range(inode, from, length, did_zero, + &ext4_iomap_zero_ops, + &ext4_iomap_write_ops, NULL); +} + /* * ext4_block_zero_page_range() zeros out a mapping of length 'length' * starting from file offset 'from'. The range to be zero'd must @@ -4650,6 +4720,9 @@ static int ext4_block_zero_page_range(struct address_= space *mapping, } else if (ext4_should_journal_data(inode)) { return ext4_journalled_block_zero_range(inode, from, length, did_zero); + } else if (ext4_inode_buffered_iomap(inode)) { + return ext4_iomap_block_zero_range(inode, from, length, + did_zero); } return ext4_block_zero_range(inode, from, length, did_zero); } @@ -5063,6 +5136,18 @@ int ext4_truncate(struct inode *inode) err =3D zero_len; goto out_trace; } + /* + * inodes using the iomap buffered I/O path do not use the + * ordered data mode, it is necessary to write out zeroed data + * before the updating i_disksize transaction is committed. + */ + if (zero_len > 0 && ext4_inode_buffered_iomap(inode)) { + err =3D filemap_write_and_wait_range(mapping, + inode->i_size, + inode->i_size + zero_len - 1); + if (err) + return err; + } } =20 if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) --=20 2.52.0