f2fs: check the blocksize before calling generic_direct_IO path
The f2fs supports 4KB block size. If user requests dwrite with under 4KB data,
it allocates a new 4KB data block.
However, f2fs doesn't add zero data into the untouched data area inside the
newly allocated data block.
This incurs an error during the xfstest #263 test as follow.
263 12s ... [failed, exit status 1] - output mismatch (see 263.out.bad)
--- 263.out 2013-03-09 03:37:15.043967603 +0900
+++ 263.out.bad 2013-12-27 04:20:39.230203114 +0900
@@ -1,3 +1,976 @@
QA output created by 263
fsx -N 10000 -o 8192 -l 500000 -r PSIZE -t BSIZE -w BSIZE -Z
-fsx -N 10000 -o 128000 -l 500000 -r PSIZE -t BSIZE -w BSIZE -Z
+fsx -N 10000 -o 8192 -l 500000 -r PSIZE -t BSIZE -w BSIZE -Z
+truncating to largest ever: 0x12a00
+truncating to largest ever: 0x75400
+fallocating to largest ever: 0x79cbf
...
(Run 'diff -u 263.out 263.out.bad' to see the entire diff)
Ran: 263
Failures: 263
Failed 1 of 1 tests
It turns out that, when the test tries to write 2KB data with dio, the new dio
path allocates 4KB data block without filling zero data inside the remained 2KB
area. Finally, the output file contains a garbage data for that region.
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
1 file changed