linux-ext4 - Re: BUG in ext4_ind_remove

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Date:   Mon, 14 Mar 2022 14:27:51 -0700
From:   Tadeusz Struk <tadeusz.struk@...aro.org>
To:     Ritesh Harjani <riteshh@...ux.ibm.com>
Cc:     Theodore Ts'o <tytso@....edu>,
        Andreas Dilger <adilger.kernel@...ger.ca>,
        linux-ext4@...r.kernel.org
Subject: Re: BUG in ext4_ind_remove_space

On 3/6/22 21:45, Ritesh Harjani wrote:
> Just FYI - The change which we discussed to fix the max_block to max_end_block, is not correct.
> Since it will still leave 1 block at the end after punch operation, if the file has s_bitmap_maxbytes size.
> This is due to the fact that, "end" is expected to be 1 block after the end of last block.
> 
> Will try look into it to see how can we fix this.
> 
> 1210 /**
> 1211  *      ext4_ind_remove_space - remove space from the range
> 1212  *      @handle: JBD handle for this transaction
> 1213  *      @inode: inode we are dealing with
> 1214  *      @start: First block to remove
> 1215  *      @end:   One block after the last block to remove (exclusive)
> 1216  *
> 1217  *      Free the blocks in the defined range (end is exclusive endpoint of
> 1218  *      range). This is used by ext4_punch_hole().
> 1219  */
> 1220 int ext4_ind_remove_space(handle_t *handle, struct inode *inode,
> 1221                           ext4_lblk_t start, ext4_lblk_t end)
> 
> -ritesh

Hi Ritesh,
I tried to bisect it and went as far back as 4.4 and the issue still triggers there.
I couldn't build anything older than that with my compiler, but I suspect that
the issue exists even before 3.0 where ext4_fallocate() has been introduced.

-- 
Thanks,
Tadeusz