Re: [PATCH v3 01/22] ext4: simplify size updating in ext4_setattr()

[Jan Kara]

On Wed 22-04-26 10:10:21, Zhang Yi wrote:
> From: Zhang Yi <yi.zhang@xxxxxxxxxx>
> 
> The logic for updating the file size in ext4_setattr() is currently
> somewhat messy. By directly entering the error-handling path after
> failing to add an orphan inode, the unnecessary recovery process
> involving old_disksize and the file size can be avoided.
> 
> Signed-off-by: Zhang Yi <yi.zhang@xxxxxxxxxx>

Indeed, that code looks confusing for no good reason. Feel free to add:

Reviewed-by: Jan Kara <jack@xxxxxxx>

								Honza

> ---
>  fs/ext4/inode.c | 22 +++++++++-------------
>  1 file changed, 9 insertions(+), 13 deletions(-)
> 
> diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
> index c2c2d6ac7f3d..0751dc55e94f 100644
> --- a/fs/ext4/inode.c
> +++ b/fs/ext4/inode.c
> @@ -5953,7 +5953,6 @@ int ext4_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
>  	if (attr->ia_valid & ATTR_SIZE) {
>  		handle_t *handle;
>  		loff_t oldsize = inode->i_size;
> -		loff_t old_disksize;
>  		int shrink = (attr->ia_size < inode->i_size);
>  
>  		if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
> @@ -6037,6 +6036,8 @@ int ext4_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
>  			if (ext4_handle_valid(handle) && shrink) {
>  				error = ext4_orphan_add(handle, inode);
>  				orphan = 1;
> +				if (error)
> +					goto out_handle;
>  			}
>  
>  			if (shrink)
> @@ -6052,23 +6053,18 @@ int ext4_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
>  					(attr->ia_size > 0 ? attr->ia_size - 1 : 0) >>
>  					inode->i_sb->s_blocksize_bits);
>  
> -			down_write(&EXT4_I(inode)->i_data_sem);
> -			old_disksize = EXT4_I(inode)->i_disksize;
> -			EXT4_I(inode)->i_disksize = attr->ia_size;
> -
>  			/*
>  			 * We have to update i_size under i_data_sem together
>  			 * with i_disksize to avoid races with writeback code
> -			 * running ext4_wb_update_i_disksize().
> +			 * updating disksize in mpage_map_and_submit_extent().
>  			 */
> -			if (!error)
> -				i_size_write(inode, attr->ia_size);
> -			else
> -				EXT4_I(inode)->i_disksize = old_disksize;
> +			down_write(&EXT4_I(inode)->i_data_sem);
> +			i_size_write(inode, attr->ia_size);
> +			EXT4_I(inode)->i_disksize = attr->ia_size;
>  			up_write(&EXT4_I(inode)->i_data_sem);
> -			rc = ext4_mark_inode_dirty(handle, inode);
> -			if (!error)
> -				error = rc;
> +
> +			error = ext4_mark_inode_dirty(handle, inode);
> +out_handle:
>  			ext4_journal_stop(handle);
>  			if (error)
>  				goto out_mmap_sem;
> -- 
> 2.52.0
> 
-- 
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR