From: Max Reitz mreitz@redhat.com
mainline inclusion from mainline-v5.4-rc3 commit e093c4be760ebf46c131ae0dd6138865a22f46fa category: bugfix bugzilla: NA CVE: NA
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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 Reviewed-by: Carlos Maiolino cmaiolino@redhat.com Reviewed-by: Christoph Hellwig hch@lst.de Reviewed-by: Darrick J. Wong darrick.wong@oracle.com Signed-off-by: Darrick J. Wong darrick.wong@oracle.com Signed-off-by: Yang Yingliang yangyingliang@huawei.com Reviewed-by: zhangyi (F) yi.zhang@huawei.com Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- 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 3e1dd66bd676..e54f5aed30a9 100644 --- a/fs/xfs/xfs_bmap_util.c +++ b/fs/xfs/xfs_bmap_util.c @@ -869,6 +869,7 @@ 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; @@ -896,7 +897,8 @@ 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