Re: [PATCH] xfs: Fix tail rounding in xfs_alloc_file_space()

[Max Reitz <mreitz@redhat.com>]

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On 26.09.19 16:47, Carlos Maiolino wrote:
> On Thu, Sep 26, 2019 at 04:22:38PM +0200, Max Reitz wrote:
>> To ensure that all blocks touched by the range [offset, offset + count)
>> are allocated, we need to calculate the block count from the difference
>> of the range end (rounded up) and the range start (rounded down).
>>
>> Before this patch, we just round up the byte count, which may lead to
>> unaligned ranges not being fully allocated:
>>
>> $ touch test_file
>> $ block_size=$(stat -fc '%S' test_file)
>> $ fallocate -o $((block_size / 2)) -l $block_size test_file
>> $ xfs_bmap test_file
>> test_file:
>>         0: [0..7]: 1396264..1396271
>>         1: [8..15]: hole
>>
>> There should not be a hole there.  Instead, the first two blocks should
>> be fully allocated.
>>
>> With this patch applied, the result is something like this:
>>
>> $ touch test_file
>> $ block_size=$(stat -fc '%S' test_file)
>> $ fallocate -o $((block_size / 2)) -l $block_size test_file
>> $ xfs_bmap test_file
>> test_file:
>>         0: [0..15]: 11024..11039
>>
>> Signed-off-by: Max Reitz <mreitz@redhat.com>
> 
> For the patch:
> 
> Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
> 
> 
> +1 for a test in xfstests
> 
> 
> P.S.
> 
> You usually don't need to Cc: LKML for xfs-only patches, linux-xfs is enough.

OK, thanks.  I wasn’t sure because get_maintainer.pl just emits it by
default.

Max


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