diff mbox series

[v4,04/10] ext4: refactor ext4_punch_hole()

Message ID 20241216013915.3392419-5-yi.zhang@huaweicloud.com (mailing list archive)
State New
Headers show
Series ext4: clean up and refactor fallocate | expand

Commit Message

Zhang Yi Dec. 16, 2024, 1:39 a.m. UTC
From: Zhang Yi <yi.zhang@huawei.com>

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 <yi.zhang@huawei.com>
---
 fs/ext4/ext4.h  |   2 +
 fs/ext4/inode.c | 119 +++++++++++++++++++++---------------------------
 2 files changed, 55 insertions(+), 66 deletions(-)

Comments

Jan Kara Dec. 16, 2024, 3:07 p.m. UTC | #1
On Mon 16-12-24 09:39:09, Zhang Yi wrote:
> From: Zhang Yi <yi.zhang@huawei.com>
> 
> 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 <yi.zhang@huawei.com>

Looks good to me. Feel free to add:

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

								Honza

> ---
>  fs/ext4/ext4.h  |   2 +
>  fs/ext4/inode.c | 119 +++++++++++++++++++++---------------------------
>  2 files changed, 55 insertions(+), 66 deletions(-)
> 
> diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
> index 8843929b46ce..8be06d5f5b43 100644
> --- a/fs/ext4/ext4.h
> +++ b/fs/ext4/ext4.h
> @@ -367,6 +367,8 @@ struct ext4_io_submit {
>  #define EXT4_MAX_BLOCKS(size, offset, blkbits) \
>  	((EXT4_BLOCK_ALIGN(size + offset, blkbits) >> blkbits) - (offset >> \
>  								  blkbits))
> +#define EXT4_B_TO_LBLK(inode, offset) \
> +	(round_up((offset), i_blocksize(inode)) >> (inode)->i_blkbits)
>  
>  /* Translate a block number to a cluster number */
>  #define EXT4_B2C(sbi, blk)	((blk) >> (sbi)->s_cluster_bits)
> diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
> index a5ba2b71d508..7720d3700b27 100644
> --- a/fs/ext4/inode.c
> +++ b/fs/ext4/inode.c
> @@ -4008,13 +4008,13 @@ 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;
>  	handle_t *handle;
>  	unsigned int credits;
> -	int ret = 0, ret2 = 0;
> +	int ret = 0;
>  
>  	trace_ext4_punch_hole(inode, offset, length, 0);
>  
> @@ -4022,36 +4022,27 @@ 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 (!IS_ALIGNED(offset | end, sb->s_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 */
> @@ -4059,7 +4050,7 @@ 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
> @@ -4069,22 +4060,16 @@ int ext4_punch_hole(struct file *file, loff_t offset, loff_t length)
>  
>  	ret = ext4_break_layouts(inode);
>  	if (ret)
> -		goto out_dio;
> +		goto out_invalidate_lock;
>  
> -	first_block_offset = round_up(offset, sb->s_blocksize);
> -	last_block_offset = round_down((offset + length), sb->s_blocksize) - 1;
> +	ret = ext4_update_disksize_before_punch(inode, offset, length);
> +	if (ret)
> +		goto out_invalidate_lock;
>  
>  	/* Now release the pages and zero block aligned part of pages*/
> -	if (last_block_offset > first_block_offset) {
> -		ret = ext4_update_disksize_before_punch(inode, offset, length);
> -		if (ret)
> -			goto out_dio;
> -
> -		ret = ext4_truncate_page_cache_block_range(inode,
> -				first_block_offset, last_block_offset + 1);
> -		if (ret)
> -			goto out_dio;
> -	}
> +	ret = ext4_truncate_page_cache_block_range(inode, offset, end);
> +	if (ret)
> +		goto out_invalidate_lock;
>  
>  	if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
>  		credits = ext4_writepage_trans_blocks(inode);
> @@ -4094,52 +4079,54 @@ 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 = EXT4_B_TO_LBLK(inode, offset);
> +	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:
>  	inode_unlock(inode);
>  	return ret;
>  }
> -- 
> 2.46.1
>
Ojaswin Mujoo Dec. 18, 2024, 10:17 a.m. UTC | #2
On Mon, Dec 16, 2024 at 09:39:09AM +0800, Zhang Yi wrote:
> From: Zhang Yi <yi.zhang@huawei.com>
> 
> 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 <yi.zhang@huawei.com>
> ---
>  fs/ext4/ext4.h  |   2 +
>  fs/ext4/inode.c | 119 +++++++++++++++++++++---------------------------
>  2 files changed, 55 insertions(+), 66 deletions(-)
> 
> diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
> index 8843929b46ce..8be06d5f5b43 100644
> --- a/fs/ext4/ext4.h
> +++ b/fs/ext4/ext4.h
> @@ -367,6 +367,8 @@ struct ext4_io_submit {
>  #define EXT4_MAX_BLOCKS(size, offset, blkbits) \
>  	((EXT4_BLOCK_ALIGN(size + offset, blkbits) >> blkbits) - (offset >> \
>  								  blkbits))
> +#define EXT4_B_TO_LBLK(inode, offset) \
> +	(round_up((offset), i_blocksize(inode)) >> (inode)->i_blkbits)
>  
>  /* Translate a block number to a cluster number */
>  #define EXT4_B2C(sbi, blk)	((blk) >> (sbi)->s_cluster_bits)
> diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
> index a5ba2b71d508..7720d3700b27 100644
> --- a/fs/ext4/inode.c
> +++ b/fs/ext4/inode.c
> @@ -4008,13 +4008,13 @@ 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;
>  	handle_t *handle;
>  	unsigned int credits;
> -	int ret = 0, ret2 = 0;
> +	int ret = 0;
>  
>  	trace_ext4_punch_hole(inode, offset, length, 0);
>  
> @@ -4022,36 +4022,27 @@ 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 (!IS_ALIGNED(offset | end, sb->s_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 */
> @@ -4059,7 +4050,7 @@ 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
> @@ -4069,22 +4060,16 @@ int ext4_punch_hole(struct file *file, loff_t offset, loff_t length)
>  
>  	ret = ext4_break_layouts(inode);
>  	if (ret)
> -		goto out_dio;
> +		goto out_invalidate_lock;
>  
> -	first_block_offset = round_up(offset, sb->s_blocksize);
> -	last_block_offset = round_down((offset + length), sb->s_blocksize) - 1;
> +	ret = ext4_update_disksize_before_punch(inode, offset, length);

Hey Zhang,

The changes look good to me, just one question, why are we doing
disksize update unconditionally now and not only when the range 
spans a complete block or more.

(Same question for the next patch refactoring ext4_zero_range())

Regards,
ojaswin

> +	if (ret)
> +		goto out_invalidate_lock;
>  
>  	/* Now release the pages and zero block aligned part of pages*/
> -	if (last_block_offset > first_block_offset) {
> -		ret = ext4_update_disksize_before_punch(inode, offset, length);
> -		if (ret)
> -			goto out_dio;
> -
> -		ret = ext4_truncate_page_cache_block_range(inode,
> -				first_block_offset, last_block_offset + 1);
> -		if (ret)
> -			goto out_dio;
> -	}
> +	ret = ext4_truncate_page_cache_block_range(inode, offset, end);
> +	if (ret)
> +		goto out_invalidate_lock;
>  
>  	if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
>  		credits = ext4_writepage_trans_blocks(inode);
> @@ -4094,52 +4079,54 @@ 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 = EXT4_B_TO_LBLK(inode, offset);
> +	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:
>  	inode_unlock(inode);
>  	return ret;
>  }
> -- 
> 2.46.1
>
Zhang Yi Dec. 18, 2024, 1:13 p.m. UTC | #3
On 2024/12/18 18:17, Ojaswin Mujoo wrote:
> On Mon, Dec 16, 2024 at 09:39:09AM +0800, Zhang Yi wrote:
>> From: Zhang Yi <yi.zhang@huawei.com>
>>
>> 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 <yi.zhang@huawei.com>
>> ---
>>  fs/ext4/ext4.h  |   2 +
>>  fs/ext4/inode.c | 119 +++++++++++++++++++++---------------------------
>>  2 files changed, 55 insertions(+), 66 deletions(-)
>>
>> diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
>> index 8843929b46ce..8be06d5f5b43 100644
>> --- a/fs/ext4/ext4.h
>> +++ b/fs/ext4/ext4.h
>> @@ -367,6 +367,8 @@ struct ext4_io_submit {
>>  #define EXT4_MAX_BLOCKS(size, offset, blkbits) \
>>  	((EXT4_BLOCK_ALIGN(size + offset, blkbits) >> blkbits) - (offset >> \
>>  								  blkbits))
>> +#define EXT4_B_TO_LBLK(inode, offset) \
>> +	(round_up((offset), i_blocksize(inode)) >> (inode)->i_blkbits)
>>  
>>  /* Translate a block number to a cluster number */
>>  #define EXT4_B2C(sbi, blk)	((blk) >> (sbi)->s_cluster_bits)
>> diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
>> index a5ba2b71d508..7720d3700b27 100644
>> --- a/fs/ext4/inode.c
>> +++ b/fs/ext4/inode.c
[..]
>> @@ -4069,22 +4060,16 @@ int ext4_punch_hole(struct file *file, loff_t offset, loff_t length)
>>  
>>  	ret = ext4_break_layouts(inode);
>>  	if (ret)
>> -		goto out_dio;
>> +		goto out_invalidate_lock;
>>  
>> -	first_block_offset = round_up(offset, sb->s_blocksize);
>> -	last_block_offset = round_down((offset + length), sb->s_blocksize) - 1;
>> +	ret = ext4_update_disksize_before_punch(inode, offset, length);
> 
> Hey Zhang,
> 
> The changes look good to me, just one question, why are we doing
> disksize update unconditionally now and not only when the range 
> spans a complete block or more.
> 

I want to simplify the code. We only need to update the disksize when
the end of the punching or zeroing range is >= the EOF and i_disksize
is less than i_size. ext4_update_disksize_before_punch() has already
performed this check and has ruled out most cases. Therefore, I
believe that calling it unconditionally will not incur significant
costs.

Thanks,
Yi.
Ojaswin Mujoo Dec. 19, 2024, 7:11 a.m. UTC | #4
On Wed, Dec 18, 2024 at 09:13:46PM +0800, Zhang Yi wrote:
> On 2024/12/18 18:17, Ojaswin Mujoo wrote:
> > On Mon, Dec 16, 2024 at 09:39:09AM +0800, Zhang Yi wrote:
> >> From: Zhang Yi <yi.zhang@huawei.com>
> >>
> >> 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 <yi.zhang@huawei.com>
> >> ---
> >>  fs/ext4/ext4.h  |   2 +
> >>  fs/ext4/inode.c | 119 +++++++++++++++++++++---------------------------
> >>  2 files changed, 55 insertions(+), 66 deletions(-)
> >>
> >> diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
> >> index 8843929b46ce..8be06d5f5b43 100644
> >> --- a/fs/ext4/ext4.h
> >> +++ b/fs/ext4/ext4.h
> >> @@ -367,6 +367,8 @@ struct ext4_io_submit {
> >>  #define EXT4_MAX_BLOCKS(size, offset, blkbits) \
> >>  	((EXT4_BLOCK_ALIGN(size + offset, blkbits) >> blkbits) - (offset >> \
> >>  								  blkbits))
> >> +#define EXT4_B_TO_LBLK(inode, offset) \
> >> +	(round_up((offset), i_blocksize(inode)) >> (inode)->i_blkbits)
> >>  
> >>  /* Translate a block number to a cluster number */
> >>  #define EXT4_B2C(sbi, blk)	((blk) >> (sbi)->s_cluster_bits)
> >> diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
> >> index a5ba2b71d508..7720d3700b27 100644
> >> --- a/fs/ext4/inode.c
> >> +++ b/fs/ext4/inode.c
> [..]
> >> @@ -4069,22 +4060,16 @@ int ext4_punch_hole(struct file *file, loff_t offset, loff_t length)
> >>  
> >>  	ret = ext4_break_layouts(inode);
> >>  	if (ret)
> >> -		goto out_dio;
> >> +		goto out_invalidate_lock;
> >>  
> >> -	first_block_offset = round_up(offset, sb->s_blocksize);
> >> -	last_block_offset = round_down((offset + length), sb->s_blocksize) - 1;
> >> +	ret = ext4_update_disksize_before_punch(inode, offset, length);
> > 
> > Hey Zhang,
> > 
> > The changes look good to me, just one question, why are we doing
> > disksize update unconditionally now and not only when the range 
> > spans a complete block or more.
> > 
> 
> I want to simplify the code. We only need to update the disksize when
> the end of the punching or zeroing range is >= the EOF and i_disksize
> is less than i_size. ext4_update_disksize_before_punch() has already
> performed this check and has ruled out most cases. Therefore, I
> believe that calling it unconditionally will not incur significant
> costs.

Okay sure, feel free to add:

Reviewed-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>

Regards,
ojaswin
> 
> Thanks,
> Yi.
>
diff mbox series

Patch

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 8843929b46ce..8be06d5f5b43 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -367,6 +367,8 @@  struct ext4_io_submit {
 #define EXT4_MAX_BLOCKS(size, offset, blkbits) \
 	((EXT4_BLOCK_ALIGN(size + offset, blkbits) >> blkbits) - (offset >> \
 								  blkbits))
+#define EXT4_B_TO_LBLK(inode, offset) \
+	(round_up((offset), i_blocksize(inode)) >> (inode)->i_blkbits)
 
 /* Translate a block number to a cluster number */
 #define EXT4_B2C(sbi, blk)	((blk) >> (sbi)->s_cluster_bits)
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index a5ba2b71d508..7720d3700b27 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -4008,13 +4008,13 @@  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;
 	handle_t *handle;
 	unsigned int credits;
-	int ret = 0, ret2 = 0;
+	int ret = 0;
 
 	trace_ext4_punch_hole(inode, offset, length, 0);
 
@@ -4022,36 +4022,27 @@  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 (!IS_ALIGNED(offset | end, sb->s_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 */
@@ -4059,7 +4050,7 @@  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
@@ -4069,22 +4060,16 @@  int ext4_punch_hole(struct file *file, loff_t offset, loff_t length)
 
 	ret = ext4_break_layouts(inode);
 	if (ret)
-		goto out_dio;
+		goto out_invalidate_lock;
 
-	first_block_offset = round_up(offset, sb->s_blocksize);
-	last_block_offset = round_down((offset + length), sb->s_blocksize) - 1;
+	ret = ext4_update_disksize_before_punch(inode, offset, length);
+	if (ret)
+		goto out_invalidate_lock;
 
 	/* Now release the pages and zero block aligned part of pages*/
-	if (last_block_offset > first_block_offset) {
-		ret = ext4_update_disksize_before_punch(inode, offset, length);
-		if (ret)
-			goto out_dio;
-
-		ret = ext4_truncate_page_cache_block_range(inode,
-				first_block_offset, last_block_offset + 1);
-		if (ret)
-			goto out_dio;
-	}
+	ret = ext4_truncate_page_cache_block_range(inode, offset, end);
+	if (ret)
+		goto out_invalidate_lock;
 
 	if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
 		credits = ext4_writepage_trans_blocks(inode);
@@ -4094,52 +4079,54 @@  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 = EXT4_B_TO_LBLK(inode, offset);
+	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:
 	inode_unlock(inode);
 	return ret;
 }