linux-ext4 - Re: [PATCH v2] ext4: Fix i_disksize exceeding i

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Message-Id: <168287753833.584010.2522737520636014795.b4-ty@mit.edu>
Date:   Sun, 30 Apr 2023 13:59:05 -0400
From:   "Theodore Ts'o" <tytso@....edu>
To:     adilger.kernel@...ger.ca, jack@...e.com, tudor.ambarus@...aro.org,
        Zhihao Cheng <chengzhihao1@...wei.com>
Cc:     "Theodore Ts'o" <tytso@....edu>, linux-ext4@...r.kernel.org,
        linux-kernel@...r.kernel.org, yi.zhang@...wei.com
Subject: Re: [PATCH v2] ext4: Fix i_disksize exceeding i_size problem in paritally written case


On Tue, 21 Mar 2023 09:37:21 +0800, Zhihao Cheng wrote:
> Following process makes i_disksize exceed i_size:
> 
> generic_perform_write
>  copied = iov_iter_copy_from_user_atomic(len) // copied < len
>  ext4_da_write_end
>  | ext4_update_i_disksize
>  |  new_i_size = pos + copied;
>  |  WRITE_ONCE(EXT4_I(inode)->i_disksize, newsize) // update i_disksize
>  | generic_write_end
>  |  copied = block_write_end(copied, len) // copied = 0
>  |   if (unlikely(copied < len))
>  |    if (!PageUptodate(page))
>  |     copied = 0;
>  |  if (pos + copied > inode->i_size) // return false
>  if (unlikely(copied == 0))
>   goto again;
>  if (unlikely(iov_iter_fault_in_readable(i, bytes))) {
>   status = -EFAULT;
>   break;
>  }
> 
> [...]

Applied, thanks!

[1/1] ext4: Fix i_disksize exceeding i_size problem in paritally written case
      commit: 1dedde690303c05ef732b7c5c8356fdf60a4ade3

Best regards,
-- 
Theodore Ts'o <tytso@....edu>