From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 88F22147C71; Mon, 18 Nov 2024 23:27:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731972433; cv=none; b=j643NbKAgm/442IYsdxQq7gzM4eF5vHbR7bqFbt/JyVBKSkJjKdn4C6UWiElv+fZ48oU+g++AZ+5ZsVV1IuSBgkDYWhMltc4Cq5zl+HxeCwcp3Biy48T29PlqbgvAZEmGRe6DQghVMSp0gMI11eaPKcW8GYdxcDc1t/o4YcDVWg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731972433; c=relaxed/simple; bh=7QPZIDne9o93BGUUovfbC0lKxWtZu//qeS4e3zdFdV8=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=VSsnmlnJeC3iibnfxU+5A2SBuezNA5OwRbzyjHcsYfS7CfezZAAa9ztUPBFDTmUAhL4M5qtOUYtv3CX1htfExWPB0INp8OVv+GZdGAk9+CJ1MC/EK1DzrJRKbp9yLkSzeBLrY1FSf4pvxLrn6xOR/8Fgs7pdxhH0UbjqOkYDkj8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=hhuqOd5S; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="hhuqOd5S" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2192DC4CECC; Mon, 18 Nov 2024 23:27:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1731972433; bh=7QPZIDne9o93BGUUovfbC0lKxWtZu//qeS4e3zdFdV8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=hhuqOd5SqDW7NW8lx0a5T9PhrKS5dcGtnEm1E4tZHVKtoYkKIPUpdpKo9xB1IdQCV u7n7mMV++inl2ih+xTT3Wm9F3Eqdn1h5PIHCRChYjybx/w+DAExa23FZ0/yrGk+cAo +0ACvcy+bv3sO+e0CPwqReA/bB2kgvT4tLWbEHau5WlAKW9hyMJ+dPAsZkCx6b5Hh7 EDt6c9TXNAouWV5np8t5x5/doemFCP/yTiX7+/HbONED1sK8/N0h+2E4wjCeOlkLp0 qCFqVQXSTjUvMfBmnFCNtcWgRJ8vkPEOr92QoD6qI+eAvgoPDhDbMNLUZOkKTMq3SB zjFVYPCGb3g7g== Date: Mon, 18 Nov 2024 15:27:12 -0800 From: "Darrick J. Wong" To: Zhang Yi Cc: linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, tytso@mit.edu, adilger.kernel@dilger.ca, jack@suse.cz, ritesh.list@gmail.com, hch@infradead.org, david@fromorbit.com, zokeefe@google.com, yi.zhang@huawei.com, chengzhihao1@huawei.com, yukuai3@huawei.com, yangerkun@huawei.com Subject: Re: [PATCH 04/27] ext4: refactor ext4_punch_hole() Message-ID: <20241118232712.GB9417@frogsfrogsfrogs> References: <20241022111059.2566137-1-yi.zhang@huaweicloud.com> <20241022111059.2566137-5-yi.zhang@huaweicloud.com> Precedence: bulk X-Mailing-List: linux-ext4@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20241022111059.2566137-5-yi.zhang@huaweicloud.com> On Tue, Oct 22, 2024 at 07:10:35PM +0800, Zhang Yi wrote: > From: Zhang Yi > > The current implementation of ext4_punch_hole() contains complex > position calculations and stale error tags. To improve the code's > clarity and maintainability, it is essential to clean up the code and > improve its readability, this can be achieved by: a) simplifying and > renaming variables; b) eliminating unnecessary position calculations; > c) writing back all data in data=journal mode, and drop page cache from > the original offset to the end, rather than using aligned blocks, > d) renaming the stale error tags. > > Signed-off-by: Zhang Yi > --- > fs/ext4/inode.c | 140 +++++++++++++++++++++--------------------------- > 1 file changed, 62 insertions(+), 78 deletions(-) > > diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c > index 94b923afcd9c..1d128333bd06 100644 > --- a/fs/ext4/inode.c > +++ b/fs/ext4/inode.c > @@ -3955,13 +3955,14 @@ int ext4_punch_hole(struct file *file, loff_t offset, loff_t length) > { > struct inode *inode = file_inode(file); > struct super_block *sb = inode->i_sb; > - ext4_lblk_t first_block, stop_block; > + ext4_lblk_t start_lblk, end_lblk; > struct address_space *mapping = inode->i_mapping; > - loff_t first_block_offset, last_block_offset, max_length; > - struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); > + loff_t max_end = EXT4_SB(sb)->s_bitmap_maxbytes - sb->s_blocksize; > + loff_t end = offset + length; > + unsigned long blocksize = i_blocksize(inode); > handle_t *handle; > unsigned int credits; > - int ret = 0, ret2 = 0; > + int ret = 0; > > trace_ext4_punch_hole(inode, offset, length, 0); > > @@ -3969,36 +3970,27 @@ int ext4_punch_hole(struct file *file, loff_t offset, loff_t length) > > /* No need to punch hole beyond i_size */ > if (offset >= inode->i_size) > - goto out_mutex; > + goto out; > > /* > - * If the hole extends beyond i_size, set the hole > - * to end after the page that contains i_size > + * If the hole extends beyond i_size, set the hole to end after > + * the page that contains i_size, and also make sure that the hole > + * within one block before last range. > */ > - if (offset + length > inode->i_size) { > - length = inode->i_size + > - PAGE_SIZE - (inode->i_size & (PAGE_SIZE - 1)) - > - offset; > - } > + if (end > inode->i_size) > + end = round_up(inode->i_size, PAGE_SIZE); > + if (end > max_end) > + end = max_end; > + length = end - offset; > > /* > - * For punch hole the length + offset needs to be within one block > - * before last range. Adjust the length if it goes beyond that limit. > + * Attach jinode to inode for jbd2 if we do any zeroing of partial > + * block. > */ > - max_length = sbi->s_bitmap_maxbytes - inode->i_sb->s_blocksize; > - if (offset + length > max_length) > - length = max_length - offset; > - > - if (offset & (sb->s_blocksize - 1) || > - (offset + length) & (sb->s_blocksize - 1)) { > - /* > - * Attach jinode to inode for jbd2 if we do any zeroing of > - * partial block > - */ > + if (offset & (blocksize - 1) || end & (blocksize - 1)) { IS_ALIGNED(offset | end, blocksize) ? > ret = ext4_inode_attach_jinode(inode); > if (ret < 0) > - goto out_mutex; > - > + goto out; > } > > /* Wait all existing dio workers, newcomers will block on i_rwsem */ > @@ -4006,7 +3998,7 @@ int ext4_punch_hole(struct file *file, loff_t offset, loff_t length) > > ret = file_modified(file); > if (ret) > - goto out_mutex; > + goto out; > > /* > * Prevent page faults from reinstantiating pages we have released from > @@ -4016,34 +4008,24 @@ int ext4_punch_hole(struct file *file, loff_t offset, loff_t length) > > ret = ext4_break_layouts(inode); > if (ret) > - goto out_dio; > - > - first_block_offset = round_up(offset, sb->s_blocksize); > - last_block_offset = round_down((offset + length), sb->s_blocksize) - 1; > + goto out_invalidate_lock; > > - /* Now release the pages and zero block aligned part of pages*/ > - if (last_block_offset > first_block_offset) { > + /* > + * For journalled data we need to write (and checkpoint) pages > + * before discarding page cache to avoid inconsitent data on inconsistent > + * disk in case of crash before punching trans is committed. > + */ > + if (ext4_should_journal_data(inode)) { > + ret = filemap_write_and_wait_range(mapping, offset, end - 1); > + } else { > ret = ext4_update_disksize_before_punch(inode, offset, length); > - if (ret) > - goto out_dio; > - > - /* > - * For journalled data we need to write (and checkpoint) pages > - * before discarding page cache to avoid inconsitent data on > - * disk in case of crash before punching trans is committed. > - */ > - if (ext4_should_journal_data(inode)) { > - ret = filemap_write_and_wait_range(mapping, > - first_block_offset, last_block_offset); > - if (ret) > - goto out_dio; > - } > - > - ext4_truncate_folios_range(inode, first_block_offset, > - last_block_offset + 1); > - truncate_pagecache_range(inode, first_block_offset, > - last_block_offset); > + ext4_truncate_folios_range(inode, offset, end); > } > + if (ret) > + goto out_invalidate_lock; > + > + /* Now release the pages and zero block aligned part of pages*/ > + truncate_pagecache_range(inode, offset, end - 1); > > if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) > credits = ext4_writepage_trans_blocks(inode); > @@ -4053,52 +4035,54 @@ int ext4_punch_hole(struct file *file, loff_t offset, loff_t length) > if (IS_ERR(handle)) { > ret = PTR_ERR(handle); > ext4_std_error(sb, ret); > - goto out_dio; > + goto out_invalidate_lock; > } > > - ret = ext4_zero_partial_blocks(handle, inode, offset, > - length); > + ret = ext4_zero_partial_blocks(handle, inode, offset, length); > if (ret) > - goto out_stop; > - > - first_block = (offset + sb->s_blocksize - 1) >> > - EXT4_BLOCK_SIZE_BITS(sb); > - stop_block = (offset + length) >> EXT4_BLOCK_SIZE_BITS(sb); > + goto out_handle; > > /* If there are blocks to remove, do it */ > - if (stop_block > first_block) { > - ext4_lblk_t hole_len = stop_block - first_block; > + start_lblk = round_up(offset, blocksize) >> inode->i_blkbits; egad I wish ext4 had nicer unit conversion helpers. static inline ext4_lblk_t EXT4_B_TO_LBLK(struct ext4_sb_info *sbi, ..., loff_t offset) { return round_up(offset, blocksize) >> inode->i_blkbits; } start_lblk = EXT4_B_TO_LBLK(sbi, offset); ah well. > + end_lblk = end >> inode->i_blkbits; > + > + if (end_lblk > start_lblk) { > + ext4_lblk_t hole_len = end_lblk - start_lblk; > > down_write(&EXT4_I(inode)->i_data_sem); > ext4_discard_preallocations(inode); > > - ext4_es_remove_extent(inode, first_block, hole_len); > + ext4_es_remove_extent(inode, start_lblk, hole_len); > > if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) > - ret = ext4_ext_remove_space(inode, first_block, > - stop_block - 1); > + ret = ext4_ext_remove_space(inode, start_lblk, > + end_lblk - 1); > else > - ret = ext4_ind_remove_space(handle, inode, first_block, > - stop_block); > + ret = ext4_ind_remove_space(handle, inode, start_lblk, > + end_lblk); > + if (ret) { > + up_write(&EXT4_I(inode)->i_data_sem); > + goto out_handle; > + } > > - ext4_es_insert_extent(inode, first_block, hole_len, ~0, > + ext4_es_insert_extent(inode, start_lblk, hole_len, ~0, > EXTENT_STATUS_HOLE, 0); > up_write(&EXT4_I(inode)->i_data_sem); > } > - ext4_fc_track_range(handle, inode, first_block, stop_block); > + ext4_fc_track_range(handle, inode, start_lblk, end_lblk); > + > + ret = ext4_mark_inode_dirty(handle, inode); > + if (unlikely(ret)) > + goto out_handle; > + > + ext4_update_inode_fsync_trans(handle, inode, 1); > if (IS_SYNC(inode)) > ext4_handle_sync(handle); > - > - ret2 = ext4_mark_inode_dirty(handle, inode); > - if (unlikely(ret2)) > - ret = ret2; > - if (ret >= 0) > - ext4_update_inode_fsync_trans(handle, inode, 1); > -out_stop: > +out_handle: > ext4_journal_stop(handle); > -out_dio: > +out_invalidate_lock: > filemap_invalidate_unlock(mapping); > -out_mutex: > +out: Why drop "_mutex"? You're unlocking *something* on the way out. --D > inode_unlock(inode); > return ret; > } > -- > 2.46.1 > >