From e093c4be760ebf46c131ae0dd6138865a22f46fa Mon Sep 17 00:00:00 2001
From: Max Reitz <mreitz@redhat.com>
Date: Mon, 30 Sep 2019 11:29:44 -0700
Subject: [PATCH] xfs: Fix tail rounding in xfs_alloc_file_space()
Git-commit: e093c4be760ebf46c131ae0dd6138865a22f46fa
Patch-mainline: v5.4-rc3
References: bsc#1161087, bsc#1153917
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>
Acked-by: Anthony Iliopoulos <ailiopoulos@suse.com>
---
fs/xfs/xfs_bmap_util.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
--- a/fs/xfs/xfs_bmap_util.c
+++ b/fs/xfs/xfs_bmap_util.c
@@ -885,6 +885,7 @@
xfs_filblks_t allocatesize_fsb;
xfs_extlen_t extsz, temp;
xfs_fileoff_t startoffset_fsb;
+ xfs_fileoff_t endoffset_fsb;
xfs_fsblock_t firstfsb;
int nimaps;
int quota_flag;
@@ -914,7 +915,8 @@
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