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| author | Qu Wenruo <wqu@suse.com> | 2021-03-08 17:20:17 +0800 |
|---|---|---|
| committer | David Sterba <dsterba@suse.com> | 2021-03-15 16:56:54 +0100 |
| commit | d2dcc8ed8ec650a793e81d8b2222146eb6ddd84f (patch) | |
| tree | 81b0401f86003ebe6043a082b0c2ec5392b70c3f | |
| parent | badae9c86979c459bd7d895d6d7ddc7a01131ff7 (diff) | |
| download | linux-stericsson-d2dcc8ed8ec650a793e81d8b2222146eb6ddd84f.tar.gz | |
btrfs: fix wrong offset to zero out range beyond i_size
[BUG]
The test generic/091 fails , with the following output:
fsx -N 10000 -o 128000 -l 500000 -r PSIZE -t BSIZE -w BSIZE -Z -W
mapped writes DISABLED
Seed set to 1
main: filesystem does not support fallocate mode FALLOC_FL_COLLAPSE_RANGE, disabling!
main: filesystem does not support fallocate mode FALLOC_FL_INSERT_RANGE, disabling!
skipping zero size read
truncating to largest ever: 0xe400
copying to largest ever: 0x1f400
cloning to largest ever: 0x70000
cloning to largest ever: 0x77000
fallocating to largest ever: 0x7a120
Mapped Read: non-zero data past EOF (0x3a7ff) page offset 0x800 is 0xf2e1 <<<
...
[CAUSE]
In commit c28ea613fafa ("btrfs: subpage: fix the false data csum mismatch error")
end_bio_extent_readpage() changes to only zero the range inside the bvec
for incoming subpage support.
But that commit is using incorrect offset to calculate the start.
For subpage, we can have a case that the whole bvec is beyond isize,
thus we need to calculate the correct offset.
But the offending commit is using @end (bvec end), other than @start
(bvec start) to calculate the start offset.
This means, we only zero the last byte of the bvec, not from the isize.
This stupid bug makes the range beyond isize is not properly zeroed, and
failed above test.
[FIX]
Use correct @start to calculate the range start.
Reported-by: kernel test robot <oliver.sang@intel.com>
Fixes: c28ea613fafa ("btrfs: subpage: fix the false data csum mismatch error")
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
| -rw-r--r-- | fs/btrfs/extent_io.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c index 4671c99d468ddd..f3d7be975c3a54 100644 --- a/fs/btrfs/extent_io.c +++ b/fs/btrfs/extent_io.c @@ -3020,7 +3020,7 @@ readpage_ok: */ if (page->index == end_index && i_size <= end) { u32 zero_start = max(offset_in_page(i_size), - offset_in_page(end)); + offset_in_page(start)); zero_user_segment(page, zero_start, offset_in_page(end) + 1); |