Re: [PATCH v2 07/10] ext4: refactor ext4_insert_range()

[Jan Kara <jack@suse.cz>]

On Wed 04-09-24 14:29:22, Zhang Yi wrote:
> From: Zhang Yi <yi.zhang@huawei.com>
> 
> Simplify ext4_collapse_range() and make the code style the same as
> ext4_collapse_range(), refactor it by a) rename variables, b) drop
> redundant input parameters checking, move others to under i_rwsem,
> preparing for later refactor, c) rename the three stale error tags.
> 
> Signed-off-by: Zhang Yi <yi.zhang@huawei.com>

Looks good. Feel free to add:

Reviewed-by: Jan Kara <jack@suse.cz>

								Honza

> ---
>  fs/ext4/extents.c | 95 ++++++++++++++++++++++-------------------------
>  1 file changed, 45 insertions(+), 50 deletions(-)
> 
> diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
> index 5c0b4d512531..a6c24c229cb4 100644
> --- a/fs/ext4/extents.c
> +++ b/fs/ext4/extents.c
> @@ -5391,45 +5391,37 @@ static int ext4_insert_range(struct file *file, loff_t offset, loff_t len)
>  	handle_t *handle;
>  	struct ext4_ext_path *path;
>  	struct ext4_extent *extent;
> -	ext4_lblk_t offset_lblk, len_lblk, ee_start_lblk = 0;
> +	ext4_lblk_t start_lblk, len_lblk, ee_start_lblk = 0;
>  	unsigned int credits, ee_len;
> -	int ret = 0, depth, split_flag = 0;
> -	loff_t ioffset;
> -
> -	/*
> -	 * We need to test this early because xfstests assumes that an
> -	 * insert range of (0, 1) will return EOPNOTSUPP if the file
> -	 * system does not support insert range.
> -	 */
> -	if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
> -		return -EOPNOTSUPP;
> -
> -	/* Insert range works only on fs cluster size aligned regions. */
> -	if (!IS_ALIGNED(offset | len, EXT4_CLUSTER_SIZE(sb)))
> -		return -EINVAL;
> +	int ret, depth, split_flag = 0;
> +	loff_t start;
>  
>  	trace_ext4_insert_range(inode, offset, len);
>  
> -	offset_lblk = offset >> EXT4_BLOCK_SIZE_BITS(sb);
> -	len_lblk = len >> EXT4_BLOCK_SIZE_BITS(sb);
> -
>  	inode_lock(inode);
> +
>  	/* Currently just for extent based files */
>  	if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
>  		ret = -EOPNOTSUPP;
> -		goto out_mutex;
> +		goto out;
>  	}
>  
> -	/* Check whether the maximum file size would be exceeded */
> -	if (len > inode->i_sb->s_maxbytes - inode->i_size) {
> -		ret = -EFBIG;
> -		goto out_mutex;
> +	/* Insert range works only on fs cluster size aligned regions. */
> +	if (!IS_ALIGNED(offset | len, EXT4_CLUSTER_SIZE(sb))) {
> +		ret = -EINVAL;
> +		goto out;
>  	}
>  
>  	/* Offset must be less than i_size */
>  	if (offset >= inode->i_size) {
>  		ret = -EINVAL;
> -		goto out_mutex;
> +		goto out;
> +	}
> +
> +	/* Check whether the maximum file size would be exceeded */
> +	if (len > inode->i_sb->s_maxbytes - inode->i_size) {
> +		ret = -EFBIG;
> +		goto out;
>  	}
>  
>  	/* Wait for existing dio to complete */
> @@ -5437,7 +5429,7 @@ static int ext4_insert_range(struct file *file, loff_t offset, loff_t len)
>  
>  	ret = file_modified(file);
>  	if (ret)
> -		goto out_mutex;
> +		goto out;
>  
>  	/*
>  	 * Prevent page faults from reinstantiating pages we have released from
> @@ -5447,25 +5439,24 @@ static int ext4_insert_range(struct file *file, loff_t offset, loff_t len)
>  
>  	ret = ext4_break_layouts(inode);
>  	if (ret)
> -		goto out_mmap;
> +		goto out_invalidate_lock;
>  
>  	/*
>  	 * Need to round down to align start offset to page size boundary
>  	 * for page size > block size.
>  	 */
> -	ioffset = round_down(offset, PAGE_SIZE);
> +	start = round_down(offset, PAGE_SIZE);
>  	/* Write out all dirty pages */
> -	ret = filemap_write_and_wait_range(inode->i_mapping, ioffset,
> -			LLONG_MAX);
> +	ret = filemap_write_and_wait_range(mapping, start, LLONG_MAX);
>  	if (ret)
> -		goto out_mmap;
> -	truncate_pagecache(inode, ioffset);
> +		goto out_invalidate_lock;
> +	truncate_pagecache(inode, start);
>  
>  	credits = ext4_writepage_trans_blocks(inode);
>  	handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
>  	if (IS_ERR(handle)) {
>  		ret = PTR_ERR(handle);
> -		goto out_mmap;
> +		goto out_invalidate_lock;
>  	}
>  	ext4_fc_mark_ineligible(sb, EXT4_FC_REASON_FALLOC_RANGE, handle);
>  
> @@ -5474,15 +5465,18 @@ static int ext4_insert_range(struct file *file, loff_t offset, loff_t len)
>  	EXT4_I(inode)->i_disksize += len;
>  	ret = ext4_mark_inode_dirty(handle, inode);
>  	if (ret)
> -		goto out_stop;
> +		goto out_handle;
> +
> +	start_lblk = offset >> inode->i_blkbits;
> +	len_lblk = len >> inode->i_blkbits;
>  
>  	down_write(&EXT4_I(inode)->i_data_sem);
>  	ext4_discard_preallocations(inode);
>  
> -	path = ext4_find_extent(inode, offset_lblk, NULL, 0);
> +	path = ext4_find_extent(inode, start_lblk, NULL, 0);
>  	if (IS_ERR(path)) {
>  		up_write(&EXT4_I(inode)->i_data_sem);
> -		goto out_stop;
> +		goto out_handle;
>  	}
>  
>  	depth = ext_depth(inode);
> @@ -5492,16 +5486,16 @@ static int ext4_insert_range(struct file *file, loff_t offset, loff_t len)
>  		ee_len = ext4_ext_get_actual_len(extent);
>  
>  		/*
> -		 * If offset_lblk is not the starting block of extent, split
> -		 * the extent @offset_lblk
> +		 * If start_lblk is not the starting block of extent, split
> +		 * the extent @start_lblk
>  		 */
> -		if ((offset_lblk > ee_start_lblk) &&
> -				(offset_lblk < (ee_start_lblk + ee_len))) {
> +		if ((start_lblk > ee_start_lblk) &&
> +				(start_lblk < (ee_start_lblk + ee_len))) {
>  			if (ext4_ext_is_unwritten(extent))
>  				split_flag = EXT4_EXT_MARK_UNWRIT1 |
>  					EXT4_EXT_MARK_UNWRIT2;
>  			ret = ext4_split_extent_at(handle, inode, &path,
> -					offset_lblk, split_flag,
> +					start_lblk, split_flag,
>  					EXT4_EX_NOCACHE |
>  					EXT4_GET_BLOCKS_PRE_IO |
>  					EXT4_GET_BLOCKS_METADATA_NOFAIL);
> @@ -5510,32 +5504,33 @@ static int ext4_insert_range(struct file *file, loff_t offset, loff_t len)
>  		ext4_free_ext_path(path);
>  		if (ret < 0) {
>  			up_write(&EXT4_I(inode)->i_data_sem);
> -			goto out_stop;
> +			goto out_handle;
>  		}
>  	} else {
>  		ext4_free_ext_path(path);
>  	}
>  
> -	ext4_es_remove_extent(inode, offset_lblk, EXT_MAX_BLOCKS - offset_lblk);
> +	ext4_es_remove_extent(inode, start_lblk, EXT_MAX_BLOCKS - start_lblk);
>  
>  	/*
> -	 * if offset_lblk lies in a hole which is at start of file, use
> +	 * if start_lblk lies in a hole which is at start of file, use
>  	 * ee_start_lblk to shift extents
>  	 */
>  	ret = ext4_ext_shift_extents(inode, handle,
> -		max(ee_start_lblk, offset_lblk), len_lblk, SHIFT_RIGHT);
> -
> +		max(ee_start_lblk, start_lblk), len_lblk, SHIFT_RIGHT);
>  	up_write(&EXT4_I(inode)->i_data_sem);
> +	if (ret)
> +		goto out_handle;
> +
> +	ext4_update_inode_fsync_trans(handle, inode, 1);
>  	if (IS_SYNC(inode))
>  		ext4_handle_sync(handle);
> -	if (ret >= 0)
> -		ext4_update_inode_fsync_trans(handle, inode, 1);
>  
> -out_stop:
> +out_handle:
>  	ext4_journal_stop(handle);
> -out_mmap:
> +out_invalidate_lock:
>  	filemap_invalidate_unlock(mapping);
> -out_mutex:
> +out:
>  	inode_unlock(inode);
>  	return ret;
>  }
> -- 
> 2.39.2
> 
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR