diff mbox series

[1/1] generic: test FALLOC_FL_UNSHARE when pagecache is not loaded

Message ID 169567819441.2270025.10851897053852323695.stgit@frogsfrogsfrogs (mailing list archive)
State New, archived
Headers show
Series fstests: fix unshare data corruption bug | expand

Commit Message

Darrick J. Wong Sept. 25, 2023, 9:43 p.m. UTC
From: Darrick J. Wong <djwong@kernel.org>

Add a regression test for funsharing uncached files to ensure that we
actually manage the pagecache state correctly.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
---
 tests/xfs/1936     |   88 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 tests/xfs/1936.out |    4 ++
 2 files changed, 92 insertions(+)
 create mode 100755 tests/xfs/1936
 create mode 100644 tests/xfs/1936.out

Comments

Ritesh Harjani (IBM) Sept. 26, 2023, 5:21 a.m. UTC | #1
"Darrick J. Wong" <djwong@kernel.org> writes:

> From: Darrick J. Wong <djwong@kernel.org>
>
> Add a regression test for funsharing uncached files to ensure that we
> actually manage the pagecache state correctly.
>
> Signed-off-by: Darrick J. Wong <djwong@kernel.org>
> ---
>  tests/xfs/1936     |   88 ++++++++++++++++++++++++++++++++++++++++++++++++++++
>  tests/xfs/1936.out |    4 ++
>  2 files changed, 92 insertions(+)
>  create mode 100755 tests/xfs/1936
>  create mode 100644 tests/xfs/1936.out
>
>
> diff --git a/tests/xfs/1936 b/tests/xfs/1936
> new file mode 100755
> index 0000000000..e07b8f4796
> --- /dev/null
> +++ b/tests/xfs/1936
> @@ -0,0 +1,88 @@
> +#! /bin/bash
> +# SPDX-License-Identifier: GPL-2.0
> +# Copyright (c) 2023 Oracle.  All Rights Reserved.
> +#
> +# FS QA Test 1936
> +#
> +# This is a regression test for the kernel commit noted below.  The stale
> +# memory exposure can be exploited by creating a file with shared blocks,
> +# evicting the page cache for that file, and then funshareing at least one
> +# memory page's worth of data.  iomap will mark the page uptodate and dirty
> +# without ever reading the ondisk contents.
> +#
> +. ./common/preamble
> +_begin_fstest auto quick unshare clone
> +
> +_cleanup()
> +{
> +	cd /
> +	rm -r -f $tmp.* $testdir
> +}
> +
> +# real QA test starts here
> +
> +# Import common functions.
> +. ./common/filter
> +. ./common/attr

We might as well remove above imports if we are not using those in this test.

> +. ./common/reflink
> +
> +_fixed_by_git_commit kernel XXXXXXXXXXXXX \
> +	"iomap: don't skip reading in !uptodate folios when unsharing a range"

Once I guess it is merged, we will have the commit-id. Ohh wait, we have
it already right? 

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=35d30c9cf12730a1e37053dfde4007c7cc452d1a

With that the testcode looks good to me. Thanks for finding an easy
reproducer. Please feel free to add - 

Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>

-ritesh
Darrick J. Wong Sept. 26, 2023, 2:47 p.m. UTC | #2
On Tue, Sep 26, 2023 at 10:51:19AM +0530, Ritesh Harjani wrote:
> "Darrick J. Wong" <djwong@kernel.org> writes:
> 
> > From: Darrick J. Wong <djwong@kernel.org>
> >
> > Add a regression test for funsharing uncached files to ensure that we
> > actually manage the pagecache state correctly.
> >
> > Signed-off-by: Darrick J. Wong <djwong@kernel.org>
> > ---
> >  tests/xfs/1936     |   88 ++++++++++++++++++++++++++++++++++++++++++++++++++++
> >  tests/xfs/1936.out |    4 ++
> >  2 files changed, 92 insertions(+)
> >  create mode 100755 tests/xfs/1936
> >  create mode 100644 tests/xfs/1936.out
> >
> >
> > diff --git a/tests/xfs/1936 b/tests/xfs/1936
> > new file mode 100755
> > index 0000000000..e07b8f4796
> > --- /dev/null
> > +++ b/tests/xfs/1936
> > @@ -0,0 +1,88 @@
> > +#! /bin/bash
> > +# SPDX-License-Identifier: GPL-2.0
> > +# Copyright (c) 2023 Oracle.  All Rights Reserved.
> > +#
> > +# FS QA Test 1936
> > +#
> > +# This is a regression test for the kernel commit noted below.  The stale
> > +# memory exposure can be exploited by creating a file with shared blocks,
> > +# evicting the page cache for that file, and then funshareing at least one
> > +# memory page's worth of data.  iomap will mark the page uptodate and dirty
> > +# without ever reading the ondisk contents.
> > +#
> > +. ./common/preamble
> > +_begin_fstest auto quick unshare clone
> > +
> > +_cleanup()
> > +{
> > +	cd /
> > +	rm -r -f $tmp.* $testdir
> > +}
> > +
> > +# real QA test starts here
> > +
> > +# Import common functions.
> > +. ./common/filter
> > +. ./common/attr
> 
> We might as well remove above imports if we are not using those in this test.

<nod>

> > +. ./common/reflink
> > +
> > +_fixed_by_git_commit kernel XXXXXXXXXXXXX \
> > +	"iomap: don't skip reading in !uptodate folios when unsharing a range"
> 
> Once I guess it is merged, we will have the commit-id. Ohh wait, we have
> it already right? 
> 
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=35d30c9cf12730a1e37053dfde4007c7cc452d1a

Oops, yeah, I'll update the tag.

> With that the testcode looks good to me. Thanks for finding an easy
> reproducer. Please feel free to add - 
> 
> Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>

Thanks!

> -ritesh
diff mbox series

Patch

diff --git a/tests/xfs/1936 b/tests/xfs/1936
new file mode 100755
index 0000000000..e07b8f4796
--- /dev/null
+++ b/tests/xfs/1936
@@ -0,0 +1,88 @@ 
+#! /bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (c) 2023 Oracle.  All Rights Reserved.
+#
+# FS QA Test 1936
+#
+# This is a regression test for the kernel commit noted below.  The stale
+# memory exposure can be exploited by creating a file with shared blocks,
+# evicting the page cache for that file, and then funshareing at least one
+# memory page's worth of data.  iomap will mark the page uptodate and dirty
+# without ever reading the ondisk contents.
+#
+. ./common/preamble
+_begin_fstest auto quick unshare clone
+
+_cleanup()
+{
+	cd /
+	rm -r -f $tmp.* $testdir
+}
+
+# real QA test starts here
+
+# Import common functions.
+. ./common/filter
+. ./common/attr
+. ./common/reflink
+
+_fixed_by_git_commit kernel XXXXXXXXXXXXX \
+	"iomap: don't skip reading in !uptodate folios when unsharing a range"
+
+# real QA test starts here
+_require_test_reflink
+_require_cp_reflink
+_require_xfs_io_command "funshare"
+
+testdir=$TEST_DIR/test-$seq
+rm -rf $testdir
+mkdir $testdir
+
+# Create a file that is at least four pages in size and aligned to the
+# file allocation unit size so that we don't trigger any unnecessary zeroing.
+pagesz=$(_get_page_size)
+alloc_unit=$(_get_file_block_size $TEST_DIR)
+filesz=$(( ( (4 * pagesz) + alloc_unit - 1) / alloc_unit * alloc_unit))
+
+echo "Create the original file and a clone"
+_pwrite_byte 0x61 0 $filesz $testdir/file2.chk >> $seqres.full
+_pwrite_byte 0x61 0 $filesz $testdir/file1 >> $seqres.full
+_cp_reflink $testdir/file1 $testdir/file2
+_cp_reflink $testdir/file1 $testdir/file3
+
+_test_cycle_mount
+
+cat $testdir/file3 > /dev/null
+
+echo "Funshare at least one pagecache page"
+$XFS_IO_PROG -c "funshare 0 $filesz" $testdir/file2
+$XFS_IO_PROG -c "funshare 0 $filesz" $testdir/file3
+_pwrite_byte 0x61 0 $filesz $testdir/file2.chk >> $seqres.full
+
+echo "Check contents"
+
+# file2 wasn't cached when it was unshared, but it should match
+if ! cmp -s $testdir/file2.chk $testdir/file2; then
+	echo "file2.chk does not match file2"
+
+	echo "file2.chk contents" >> $seqres.full
+	od -tx1 -Ad -c $testdir/file2.chk >> $seqres.full
+	echo "file2 contents" >> $seqres.full
+	od -tx1 -Ad -c $testdir/file2 >> $seqres.full
+	echo "end bad contents" >> $seqres.full
+fi
+
+# file3 was cached when it was unshared, and it should match
+if ! cmp -s $testdir/file2.chk $testdir/file3; then
+	echo "file2.chk does not match file3"
+
+	echo "file2.chk contents" >> $seqres.full
+	od -tx1 -Ad -c $testdir/file2.chk >> $seqres.full
+	echo "file3 contents" >> $seqres.full
+	od -tx1 -Ad -c $testdir/file3 >> $seqres.full
+	echo "end bad contents" >> $seqres.full
+fi
+
+# success, all done
+status=0
+exit
diff --git a/tests/xfs/1936.out b/tests/xfs/1936.out
new file mode 100644
index 0000000000..c7c820ced5
--- /dev/null
+++ b/tests/xfs/1936.out
@@ -0,0 +1,4 @@ 
+QA output created by 1936
+Create the original file and a clone
+Funshare at least one pagecache page
+Check contents