From: "Darrick J. Wong" <darrick.wong@oracle.com>
To: Max Reitz <mreitz@redhat.com>
Cc: linux-xfs@vger.kernel.org, linux-kernel@vger.kernel.org,
Brian Foster <bfoster@redhat.com>
Subject: Re: [PATCH] xfs: Fix tail rounding in xfs_alloc_file_space()
Date: Mon, 30 Sep 2019 11:25:15 -0700 [thread overview]
Message-ID: <20190930182515.GE13108@magnolia> (raw)
In-Reply-To: <20190926142238.26973-1-mreitz@redhat.com>
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>
Looks ok, will test...
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
--D
> ---
> fs/xfs/xfs_bmap_util.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c
> index 0910cb75b65d..4f443703065e 100644
> --- a/fs/xfs/xfs_bmap_util.c
> +++ b/fs/xfs/xfs_bmap_util.c
> @@ -864,6 +864,7 @@ xfs_alloc_file_space(
> xfs_filblks_t allocatesize_fsb;
> xfs_extlen_t extsz, temp;
> xfs_fileoff_t startoffset_fsb;
> + xfs_fileoff_t endoffset_fsb;
> int nimaps;
> int quota_flag;
> int rt;
> @@ -891,7 +892,8 @@ xfs_alloc_file_space(
> imapp = &imaps[0];
> nimaps = 1;
> startoffset_fsb = XFS_B_TO_FSBT(mp, offset);
> - allocatesize_fsb = XFS_B_TO_FSB(mp, count);
> + endoffset_fsb = XFS_B_TO_FSB(mp, offset + count);
> + allocatesize_fsb = endoffset_fsb - startoffset_fsb;
>
> /*
> * Allocate file space until done or until there is an error
> --
> 2.23.0
>
prev parent reply other threads:[~2019-09-30 23:04 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-26 14:22 [PATCH] xfs: Fix tail rounding in xfs_alloc_file_space() Max Reitz
2019-09-26 14:37 ` Darrick J. Wong
2019-09-26 14:40 ` Max Reitz
2019-09-26 14:47 ` Carlos Maiolino
2019-09-26 15:28 ` Max Reitz
2019-09-30 7:48 ` Christoph Hellwig
2019-09-30 18:25 ` Darrick J. Wong [this message]
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