On Wed, Feb 5, 2025 at 9:59 PM Qu Wenruo <wqu@xxxxxxxx> wrote: > > [BUG] > With recent kernel patch "btrfs: always fallback to buffered write if the > inode requires checksum", the test case btrfs/226 will fail with the > following error: > > FSTYP -- btrfs > PLATFORM -- Linux/x86_64 btrfs-vm 6.13.0-rc6-custom+ #209 SMP PREEMPT_DYNAMIC Fri Jan 24 17:23:03 ACDT 2025 > MKFS_OPTIONS -- /dev/mapper/test-scratch1 > MOUNT_OPTIONS -- /dev/mapper/test-scratch1 /mnt/scratch > > btrfs/226 1s ... - output mismatch (see /home/adam/xfstests/results//btrfs/226.out.bad) > --- tests/btrfs/226.out 2024-04-12 14:04:03.080000035 +0930 > +++ /home/adam/xfstests/results//btrfs/226.out.bad 2025-02-06 08:23:42.564298585 +1030 > @@ -39,14 +39,11 @@ > Testing write against prealloc extent at eof > wrote 65536/65536 bytes at offset 0 > XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) > -wrote 65536/65536 bytes at offset 65536 > -XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) > +pwrite: Resource temporarily unavailable > File after write: > ... > (Run 'diff -u /home/adam/xfstests/tests/btrfs/226.out /home/adam/xfstests/results//btrfs/226.out.bad' to see the entire diff) > Ran: btrfs/226 > Failures: btrfs/226 > Failed 1 of 1 tests > > [CAUSE] > That kernel patch makes btrfs to always fallback to buffered IO if the > target inode requires data checksum. > > This is to avoid more deadly problems of mismatched data checksum. > > But this also means, for inodes with data checksum, RWF_NOWAIT will > always fail, because we will wait writing back the page cache, thus > breaking the RWF_NOWAIT requirement. > > [FIX] > Update the test case to utilize nodatasum mount option, so that the > direct-IO will not fallback to buffered ones unconditionally. > > Reported-by: Filipe Manana <fdmanana@xxxxxxxxxx> > Signed-off-by: Qu Wenruo <wqu@xxxxxxxx> > --- > tests/btrfs/226 | 7 ++++++- > 1 file changed, 6 insertions(+), 1 deletion(-) > > diff --git a/tests/btrfs/226 b/tests/btrfs/226 > index 70275d0aa2d8..359813c4f394 100755 > --- a/tests/btrfs/226 > +++ b/tests/btrfs/226 > @@ -21,7 +21,12 @@ _require_xfs_io_command falloc -k > _require_xfs_io_command fpunch > > _scratch_mkfs >>$seqres.full 2>&1 > -_scratch_mount > + > +# This test involves RWF_NOWAIT direct IOs, but for inodes with data checksum, involves -> exercises > +# btrfs will fall back to buffered IO unconditionally to prevent data checksum > +# mimsatch, and that will break RWF_NOWAIT with -EAGAIN. mimsatch -> mismatch > +# So here we have to go with nodatasum mount option. The whole text could be shorter and clear: # RWF_NOWAIT only works with direct IO, which requires an inode with nodatasum (otherwise it falls back to buffered IO). Otherwise it looks fine, so: Reviewed-by: Filipe Manana <fdmanana@xxxxxxxx> Thanks. > +_scratch_mount -o nodatasum > > # Test a write against COW file/extent - should fail with -EAGAIN. Disable the > # NOCOW attribute of the file just in case MOUNT_OPTIONS has "-o nodatacow". > -- > 2.48.1 >
