On Thu, Oct 15, 2020 at 5:13 PM Jan Kara <jack@xxxxxxx> wrote:
>
> On Thu 15-10-20 16:36:38, fdmanana@xxxxxxxxxx wrote:
> > From: Filipe Manana <fdmanana@xxxxxxxx>
> >
> > Verify some attempts to write into a file using RWF_NOWAIT:
> >
> > 1) Writing into a fallocated extent that starts at eof should work;
>
> Why? We need to update i_size which requires transaction start and e.g.
> ext4 does not support that in non-blocking mode...
Ah, ok it makes sense then. In btrfs we do it asynchronously (in a
work queue) and always have to update the inode metadata anyway.
Ok, I'll remove that case from the test then.
Thanks.
>
> Honza
>
> > 2) Writing into a hole should fail;
> > 3) Writing into a range that is partially allocated should fail.
> >
> > This is motivated by several bugs that btrfs and ext4 had and were fixed
> > by the following kernel commits:
> >
> > 4b1946284dd6 ("btrfs: fix failure of RWF_NOWAIT write into prealloc extent beyond eof")
> > 260a63395f90 ("btrfs: fix RWF_NOWAIT write not failling when we need to cow")
> > 0b3171b6d195 ("ext4: do not block RWF_NOWAIT dio write on unallocated space")
> >
> > At the moment, on a 5.9-rc6 kernel at least, ext4 is failing for case 1),
> > but when I found and fixed case 1) in btrfs, around kernel 5.7, it was not
> > failing on ext4, so some regression happened in the meanwhile. For xfs and
> > btrfs on a 5.9 kernel, all the three cases pass.
> >
> > Signed-off-by: Filipe Manana <fdmanana@xxxxxxxx>
> > ---
> > tests/generic/613 | 74 +++++++++++++++++++++++++++++++++++++++++++
> > tests/generic/613.out | 19 +++++++++++
> > tests/generic/group | 1 +
> > 3 files changed, 94 insertions(+)
> > create mode 100755 tests/generic/613
> > create mode 100644 tests/generic/613.out
> >
> > diff --git a/tests/generic/613 b/tests/generic/613
> > new file mode 100755
> > index 00000000..931876dc
> > --- /dev/null
> > +++ b/tests/generic/613
> > @@ -0,0 +1,74 @@
> > +#! /bin/bash
> > +# SPDX-License-Identifier: GPL-2.0
> > +# Copyright (C) 2020 SUSE Linux Products GmbH. All Rights Reserved.
> > +#
> > +# FS QA Test No. 613
> > +#
> > +# Verify some attempts to write into a file using RWF_NOWAIT:
> > +#
> > +# 1) Writing into a fallocated extent that starts at eof should work;
> > +# 2) Writing into a hole should fail;
> > +# 3) Writing into a range that is partially allocated should fail.
> > +#
> > +seq=`basename $0`
> > +seqres=$RESULT_DIR/$seq
> > +echo "QA output created by $seq"
> > +tmp=/tmp/$$
> > +status=1 # failure is the default!
> > +trap "_cleanup; exit \$status" 0 1 2 3 15
> > +
> > +_cleanup()
> > +{
> > + cd /
> > + rm -f $tmp.*
> > +}
> > +
> > +# get standard environment, filters and checks
> > +. ./common/rc
> > +. ./common/filter
> > +
> > +# real QA test starts here
> > +_supported_fs generic
> > +_require_scratch
> > +_require_odirect
> > +_require_xfs_io_command pwrite -N
> > +_require_xfs_io_command falloc -k
> > +_require_xfs_io_command fpunch
> > +
> > +rm -f $seqres.full
> > +
> > +_scratch_mkfs >>$seqres.full 2>&1
> > +_scratch_mount
> > +
> > +echo "Creating file"
> > +$XFS_IO_PROG -f -d -c "pwrite -S 0xab 0 512K" $SCRATCH_MNT/foo | _filter_xfs_io
> > +
> > +# Now add an unwritten extent using fallocate without bumping the file size and
> > +# then attempt to do a RWF_NOWAIT write into this extent. It should not fail.
> > +echo "Writing into fallocated extent at eof"
> > +$XFS_IO_PROG -c "falloc -k 512K 512K" \
> > + -d -c "pwrite -N -V 1 -S 0xcd -b 512K 512K 512K" \
> > + $SCRATCH_MNT/foo | _filter_xfs_io
> > +
> > +# Now punch a hole and try a RWF_NOWAIT write into the hole. It should fail.
> > +echo "Writing into a hole"
> > +$XFS_IO_PROG -c "fpunch 0 256K" \
> > + -d -c "pwrite -N -V 1 -S 0xff -b 128K 0 128K" \
> > + $SCRATCH_MNT/foo | _filter_xfs_io
> > +
> > +# Allocate an extent for the first half of the hole, then attempt to write into
> > +# a range that covers the new extent and the hole. It should fail.
> > +echo "Writing into a range partially allocated (ending with a hole)"
> > +$XFS_IO_PROG -c "falloc 0 128K" \
> > + -d -c "pwrite -N -V 1 -S 0xef -b 256K 0 256K" \
> > + $SCRATCH_MNT/foo | _filter_xfs_io
> > +
> > +# Just double check none of the writes above that should fail did not change the
> > +# file data in an unexpected way. First 256K of file data should be all zeros,
> > +# the range from 256K to 512K should have all bytes with a value of 0xab and the
> > +# range from 512K to 1M should have all bytes with a value of 0xcd.
> > +echo "Final file content:"
> > +od -A d -t x1 $SCRATCH_MNT/foo
> > +
> > +status=0
> > +exit
> > diff --git a/tests/generic/613.out b/tests/generic/613.out
> > new file mode 100644
> > index 00000000..a542fa5b
> > --- /dev/null
> > +++ b/tests/generic/613.out
> > @@ -0,0 +1,19 @@
> > +QA output created by 613
> > +Creating file
> > +wrote 524288/524288 bytes at offset 0
> > +XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
> > +Writing into fallocated extent at eof
> > +wrote 524288/524288 bytes at offset 524288
> > +XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
> > +Writing into a hole
> > +pwrite: Resource temporarily unavailable
> > +Writing into a range partially allocated (ending with a hole)
> > +pwrite: Resource temporarily unavailable
> > +Final file content:
> > +0000000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> > +*
> > +0262144 ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab
> > +*
> > +0524288 cd cd cd cd cd cd cd cd cd cd cd cd cd cd cd cd
> > +*
> > +1048576
> > diff --git a/tests/generic/group b/tests/generic/group
> > index 8054d874..b8bf8ec1 100644
> > --- a/tests/generic/group
> > +++ b/tests/generic/group
> > @@ -615,3 +615,4 @@
> > 610 auto quick prealloc zero
> > 611 auto quick attr
> > 612 auto quick clone
> > +613 auto quick rw prealloc punch
> > --
> > 2.28.0
> >
> --
> Jan Kara <jack@xxxxxxxx>
> SUSE Labs, CR
