* [PATCH] fstests: generic: add a basic cachestat test case
@ 2026-07-15 22:37 Qu Wenruo
2026-07-16 10:05 ` Brian Foster
0 siblings, 1 reply; 5+ messages in thread
From: Qu Wenruo @ 2026-07-15 22:37 UTC (permalink / raw)
To: fstests, linux-btrfs; +Cc: bfoster, Anand Jain, Filipe Manana
The test case is inspired by LTP, where there is a regression on 64K
page size systems with btrfs, that after a fsync, cachestat() still
report dirty pages.
The test case itself is pretty simple, fill the file with a buffered write that is
1/2/4/8/16 page sized, call cachestat() to make sure the cached/dirtied
number match the page number.
Then do a fsync(), and make sure the dirty page number reduced to 0
meanwhile cached is still the same.
Link: https://bugzilla.suse.com/show_bug.cgi?id=1270397
Reviewed-by: Anand Jain <asj@kernel.org>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
---
Changelog:
v3:
- Use golden output to greatly simplify the test case
- Do not mkfs for each size, just remove the original file
v2:
- Reject "sync" and "dax" mount options
Those mount options write back data synchronously, will screw up the
buffered write dirtied page reporting.
- Use AWK_PROG everywhere.
- Remove the unnecessary redirection for fsync
---
tests/generic/798 | 39 +++++++++++++++++++++++++++++++++++++++
tests/generic/798.out | 16 ++++++++++++++++
2 files changed, 55 insertions(+)
create mode 100755 tests/generic/798
create mode 100644 tests/generic/798.out
diff --git a/tests/generic/798 b/tests/generic/798
new file mode 100755
index 00000000..0fe37646
--- /dev/null
+++ b/tests/generic/798
@@ -0,0 +1,39 @@
+#! /bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (c) 2026 SUSE S.A. All Rights Reserved.
+#
+# FS QA Test 798
+#
+# Basic tests for cachestat()
+#
+. ./common/preamble
+_begin_fstest auto quick
+
+_require_xfs_io_command "cachestat"
+_require_scratch
+# Any mount option that writes data back synchronously should be rejected.
+# Or it will screw up the dirtied page reporting for buffered writes.
+_exclude_scratch_mount_option "dax"
+_exclude_scratch_mount_option "sync"
+
+pagesize=$(_get_page_size)
+
+_scratch_mkfs > /dev/null
+_scratch_mount
+
+for num_page in 1 2 4 8 16; do
+ size=$(($pagesize * $num_page))
+
+ echo "=== Test with $num_page pages ==="
+
+ rm -f $SCRATCH_MNT/foobar
+ $XFS_IO_PROG -f -c "pwrite -b $pagesize 0 $size" $SCRATCH_MNT/foobar > /dev/null
+ # Basic cached number reporting
+ $XFS_IO_PROG -c "cachestat 0 $size" $SCRATCH_MNT/foobar
+
+ # Test dirty page number reporting after a fsync.
+ $XFS_IO_PROG -c "fsync" -c "cachestat 0 $size" $SCRATCH_MNT/foobar
+done
+
+_scratch_unmount
+_exit 0
diff --git a/tests/generic/798.out b/tests/generic/798.out
new file mode 100644
index 00000000..ca6ead3c
--- /dev/null
+++ b/tests/generic/798.out
@@ -0,0 +1,16 @@
+QA output created by 798
+=== Test with 1 pages ===
+Cached: 1, Dirty: 1, Writeback: 0, Evicted: 0, Recently Evicted: 0
+Cached: 1, Dirty: 0, Writeback: 0, Evicted: 0, Recently Evicted: 0
+=== Test with 2 pages ===
+Cached: 2, Dirty: 2, Writeback: 0, Evicted: 0, Recently Evicted: 0
+Cached: 2, Dirty: 0, Writeback: 0, Evicted: 0, Recently Evicted: 0
+=== Test with 4 pages ===
+Cached: 4, Dirty: 4, Writeback: 0, Evicted: 0, Recently Evicted: 0
+Cached: 4, Dirty: 0, Writeback: 0, Evicted: 0, Recently Evicted: 0
+=== Test with 8 pages ===
+Cached: 8, Dirty: 8, Writeback: 0, Evicted: 0, Recently Evicted: 0
+Cached: 8, Dirty: 0, Writeback: 0, Evicted: 0, Recently Evicted: 0
+=== Test with 16 pages ===
+Cached: 16, Dirty: 16, Writeback: 0, Evicted: 0, Recently Evicted: 0
+Cached: 16, Dirty: 0, Writeback: 0, Evicted: 0, Recently Evicted: 0
--
2.51.2
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH] fstests: generic: add a basic cachestat test case
2026-07-15 22:37 [PATCH] fstests: generic: add a basic cachestat test case Qu Wenruo
@ 2026-07-16 10:05 ` Brian Foster
0 siblings, 0 replies; 5+ messages in thread
From: Brian Foster @ 2026-07-16 10:05 UTC (permalink / raw)
To: Qu Wenruo; +Cc: fstests, linux-btrfs, Anand Jain, Filipe Manana
On Thu, Jul 16, 2026 at 08:07:16AM +0930, Qu Wenruo wrote:
> The test case is inspired by LTP, where there is a regression on 64K
> page size systems with btrfs, that after a fsync, cachestat() still
> report dirty pages.
>
> The test case itself is pretty simple, fill the file with a buffered write that is
> 1/2/4/8/16 page sized, call cachestat() to make sure the cached/dirtied
> number match the page number.
>
> Then do a fsync(), and make sure the dirty page number reduced to 0
> meanwhile cached is still the same.
>
> Link: https://bugzilla.suse.com/show_bug.cgi?id=1270397
> Reviewed-by: Anand Jain <asj@kernel.org>
> Reviewed-by: Filipe Manana <fdmanana@suse.com>
> Signed-off-by: Qu Wenruo <wqu@suse.com>
> ---
> Changelog:
> v3:
> - Use golden output to greatly simplify the test case
>
> - Do not mkfs for each size, just remove the original file
>
> v2:
> - Reject "sync" and "dax" mount options
> Those mount options write back data synchronously, will screw up the
> buffered write dirtied page reporting.
>
> - Use AWK_PROG everywhere.
>
> - Remove the unnecessary redirection for fsync
> ---
Nice. Thanks for the tweaks!
Reviewed-by: Brian Foster <bfoster@redhat.com>
> tests/generic/798 | 39 +++++++++++++++++++++++++++++++++++++++
> tests/generic/798.out | 16 ++++++++++++++++
> 2 files changed, 55 insertions(+)
> create mode 100755 tests/generic/798
> create mode 100644 tests/generic/798.out
>
> diff --git a/tests/generic/798 b/tests/generic/798
> new file mode 100755
> index 00000000..0fe37646
> --- /dev/null
> +++ b/tests/generic/798
> @@ -0,0 +1,39 @@
> +#! /bin/bash
> +# SPDX-License-Identifier: GPL-2.0
> +# Copyright (c) 2026 SUSE S.A. All Rights Reserved.
> +#
> +# FS QA Test 798
> +#
> +# Basic tests for cachestat()
> +#
> +. ./common/preamble
> +_begin_fstest auto quick
> +
> +_require_xfs_io_command "cachestat"
> +_require_scratch
> +# Any mount option that writes data back synchronously should be rejected.
> +# Or it will screw up the dirtied page reporting for buffered writes.
> +_exclude_scratch_mount_option "dax"
> +_exclude_scratch_mount_option "sync"
> +
> +pagesize=$(_get_page_size)
> +
> +_scratch_mkfs > /dev/null
> +_scratch_mount
> +
> +for num_page in 1 2 4 8 16; do
> + size=$(($pagesize * $num_page))
> +
> + echo "=== Test with $num_page pages ==="
> +
> + rm -f $SCRATCH_MNT/foobar
> + $XFS_IO_PROG -f -c "pwrite -b $pagesize 0 $size" $SCRATCH_MNT/foobar > /dev/null
> + # Basic cached number reporting
> + $XFS_IO_PROG -c "cachestat 0 $size" $SCRATCH_MNT/foobar
> +
> + # Test dirty page number reporting after a fsync.
> + $XFS_IO_PROG -c "fsync" -c "cachestat 0 $size" $SCRATCH_MNT/foobar
> +done
> +
> +_scratch_unmount
> +_exit 0
> diff --git a/tests/generic/798.out b/tests/generic/798.out
> new file mode 100644
> index 00000000..ca6ead3c
> --- /dev/null
> +++ b/tests/generic/798.out
> @@ -0,0 +1,16 @@
> +QA output created by 798
> +=== Test with 1 pages ===
> +Cached: 1, Dirty: 1, Writeback: 0, Evicted: 0, Recently Evicted: 0
> +Cached: 1, Dirty: 0, Writeback: 0, Evicted: 0, Recently Evicted: 0
> +=== Test with 2 pages ===
> +Cached: 2, Dirty: 2, Writeback: 0, Evicted: 0, Recently Evicted: 0
> +Cached: 2, Dirty: 0, Writeback: 0, Evicted: 0, Recently Evicted: 0
> +=== Test with 4 pages ===
> +Cached: 4, Dirty: 4, Writeback: 0, Evicted: 0, Recently Evicted: 0
> +Cached: 4, Dirty: 0, Writeback: 0, Evicted: 0, Recently Evicted: 0
> +=== Test with 8 pages ===
> +Cached: 8, Dirty: 8, Writeback: 0, Evicted: 0, Recently Evicted: 0
> +Cached: 8, Dirty: 0, Writeback: 0, Evicted: 0, Recently Evicted: 0
> +=== Test with 16 pages ===
> +Cached: 16, Dirty: 16, Writeback: 0, Evicted: 0, Recently Evicted: 0
> +Cached: 16, Dirty: 0, Writeback: 0, Evicted: 0, Recently Evicted: 0
> --
> 2.51.2
>
^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH] fstests: generic: add a basic cachestat test case
@ 2026-07-07 0:18 Qu Wenruo
2026-07-07 11:09 ` Anand Suveer Jain
2026-07-07 11:17 ` Filipe Manana
0 siblings, 2 replies; 5+ messages in thread
From: Qu Wenruo @ 2026-07-07 0:18 UTC (permalink / raw)
To: fstests, linux-btrfs
The test case is inspired by LTP, where there is a regression on 64K
page size systems with btrfs, that after a fsync, cachestat() still
report dirty pages.
The test case itself is pretty simple, fill the file with a buffered write that is
1/2/4/8/16 page sized, call cachestat() to make sure the cached/dirtied
number match the page number.
Then do a fsync(), and make sure the dirty page number reduced to 0
meanwhile cached is still the same.
Link: https://bugzilla.suse.com/show_bug.cgi?id=1270397
Signed-off-by: Qu Wenruo <wqu@suse.com>
---
tests/generic/798 | 57 +++++++++++++++++++++++++++++++++++++++++++
tests/generic/798.out | 2 ++
2 files changed, 59 insertions(+)
create mode 100755 tests/generic/798
create mode 100644 tests/generic/798.out
diff --git a/tests/generic/798 b/tests/generic/798
new file mode 100755
index 00000000..4328475e
--- /dev/null
+++ b/tests/generic/798
@@ -0,0 +1,57 @@
+#! /bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (c) 2026 SUSE S.A. All Rights Reserved.
+#
+# FS QA Test 798
+#
+# Basic tests for cachestate()
+#
+. ./common/preamble
+_begin_fstest auto quick
+
+_require_xfs_io_command "cachestat"
+_require_scratch
+
+pagesize=$(_get_page_size)
+
+for num_page in 1 2 4 8 16; do
+ size=$(($pagesize * $num_page))
+
+ echo "=== Test with $num_page pages ===" >> $seqres.full
+ _scratch_mkfs > /dev/null
+ _scratch_mount
+
+ # Basic cached number reporting
+ $XFS_IO_PROG -f -c "pwrite -b $pagesize 0 $size" \
+ $SCRATCH_MNT/foobar >> $seqres.full
+ $XFS_IO_PROG -c "cachestat 0 $size" $SCRATCH_MNT/foobar > $tmp.output
+ cat $tmp.output >> $seqres.full
+ cached=$(cat $tmp.output | cut -f1 -d, | awk '{print $2}')
+ dirtied=$(cat $tmp.output | cut -f2 -d, | awk '{print $2}')
+
+ if [ "$cached" -ne "$num_page" ]; then
+ _fail "cached not matching the page number"
+ fi
+
+ if [ "$cached" -ne "$dirtied" ]; then
+ _fail "dirited not matching the page number"
+ fi
+ $XFS_IO_PROG -c "fsync" $SCRATCH_MNT/foobar >> $seqres.full
+
+ # Test dirty page number reporting after a fsync.
+ $XFS_IO_PROG -c "cachestat 0 $size" $SCRATCH_MNT/foobar > $tmp.output
+ cat $tmp.output >> $seqres.full
+ _scratch_unmount
+ cached=$(cat $tmp.output | cut -f1 -d, | awk '{print $2}')
+ dirtied=$(cat $tmp.output | cut -f2 -d, | awk '{print $2}')
+
+ if [ "$cached" -ne "$num_page" ]; then
+ _fail "cached not matching the page number"
+ fi
+ if [ "$dirtied" -ne 0 ]; then
+ _fail "dirtied pages not zero"
+ fi
+done
+
+echo "Silence is golden"
+_exit 0
diff --git a/tests/generic/798.out b/tests/generic/798.out
new file mode 100644
index 00000000..216d6e93
--- /dev/null
+++ b/tests/generic/798.out
@@ -0,0 +1,2 @@
+QA output created by 798
+Silence is golden
--
2.51.2
^ permalink raw reply related [flat|nested] 5+ messages in thread* Re: [PATCH] fstests: generic: add a basic cachestat test case
2026-07-07 0:18 Qu Wenruo
@ 2026-07-07 11:09 ` Anand Suveer Jain
2026-07-07 11:17 ` Filipe Manana
1 sibling, 0 replies; 5+ messages in thread
From: Anand Suveer Jain @ 2026-07-07 11:09 UTC (permalink / raw)
To: Qu Wenruo, fstests, linux-btrfs
On 7/7/26 08:18, Qu Wenruo wrote:
> The test case is inspired by LTP, where there is a regression on 64K
> page size systems with btrfs, that after a fsync, cachestat() still
> report dirty pages.
>
> The test case itself is pretty simple, fill the file with a buffered write that is
> 1/2/4/8/16 page sized, call cachestat() to make sure the cached/dirtied
> number match the page number.
>
> Then do a fsync(), and make sure the dirty page number reduced to 0
> meanwhile cached is still the same.
>
> Link: https://bugzilla.suse.com/show_bug.cgi?id=1270397
> Signed-off-by: Qu Wenruo <wqu@suse.com>
> ---
> tests/generic/798 | 57 +++++++++++++++++++++++++++++++++++++++++++
> tests/generic/798.out | 2 ++
> 2 files changed, 59 insertions(+)
> create mode 100755 tests/generic/798
> create mode 100644 tests/generic/798.out
>
> diff --git a/tests/generic/798 b/tests/generic/798
> new file mode 100755
> index 00000000..4328475e
> --- /dev/null
> +++ b/tests/generic/798
> @@ -0,0 +1,57 @@
> +#! /bin/bash
> +# SPDX-License-Identifier: GPL-2.0
> +# Copyright (c) 2026 SUSE S.A. All Rights Reserved.
> +#
> +# FS QA Test 798
> +#
> +# Basic tests for cachestate()
> +#
> +. ./common/preamble
> +_begin_fstest auto quick
> +
> +_require_xfs_io_command "cachestat"
> +_require_scratch
> +
> +pagesize=$(_get_page_size)
> +
> +for num_page in 1 2 4 8 16; do
> + size=$(($pagesize * $num_page))
> +
> + echo "=== Test with $num_page pages ===" >> $seqres.full
> + _scratch_mkfs > /dev/null
> + _scratch_mount
> +
> + # Basic cached number reporting
> + $XFS_IO_PROG -f -c "pwrite -b $pagesize 0 $size" \
> + $SCRATCH_MNT/foobar >> $seqres.full
> + $XFS_IO_PROG -c "cachestat 0 $size" $SCRATCH_MNT/foobar > $tmp.output
> + cat $tmp.output >> $seqres.full
> + cached=$(cat $tmp.output | cut -f1 -d, | awk '{print $2}')
> + dirtied=$(cat $tmp.output | cut -f2 -d, | awk '{print $2}')
> +
> + if [ "$cached" -ne "$num_page" ]; then
> + _fail "cached not matching the page number"
> + fi
> +
> + if [ "$cached" -ne "$dirtied" ]; then
> + _fail "dirited not matching the page number"
> + fi
> + $XFS_IO_PROG -c "fsync" $SCRATCH_MNT/foobar >> $seqres.full
> +
> + # Test dirty page number reporting after a fsync.
> + $XFS_IO_PROG -c "cachestat 0 $size" $SCRATCH_MNT/foobar > $tmp.output
> + cat $tmp.output >> $seqres.full
> + _scratch_unmount
> + cached=$(cat $tmp.output | cut -f1 -d, | awk '{print $2}')
> + dirtied=$(cat $tmp.output | cut -f2 -d, | awk '{print $2}')
> +
> + if [ "$cached" -ne "$num_page" ]; then
> + _fail "cached not matching the page number"
> + fi
> + if [ "$dirtied" -ne 0 ]; then
> + _fail "dirtied pages not zero"
> + fi
> +done
> +
> +echo "Silence is golden"
> +_exit 0
> diff --git a/tests/generic/798.out b/tests/generic/798.out
> new file mode 100644
> index 00000000..216d6e93
> --- /dev/null
> +++ b/tests/generic/798.out
> @@ -0,0 +1,2 @@
> +QA output created by 798
> +Silence is golden
Nice.
Reviewed-by: Anand Jain <asj@kernel.org>
Thanks
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] fstests: generic: add a basic cachestat test case
2026-07-07 0:18 Qu Wenruo
2026-07-07 11:09 ` Anand Suveer Jain
@ 2026-07-07 11:17 ` Filipe Manana
1 sibling, 0 replies; 5+ messages in thread
From: Filipe Manana @ 2026-07-07 11:17 UTC (permalink / raw)
To: Qu Wenruo; +Cc: fstests, linux-btrfs
On Tue, Jul 7, 2026 at 1:20 AM Qu Wenruo <wqu@suse.com> wrote:
>
> The test case is inspired by LTP, where there is a regression on 64K
> page size systems with btrfs, that after a fsync, cachestat() still
> report dirty pages.
>
> The test case itself is pretty simple, fill the file with a buffered write that is
> 1/2/4/8/16 page sized, call cachestat() to make sure the cached/dirtied
> number match the page number.
>
> Then do a fsync(), and make sure the dirty page number reduced to 0
> meanwhile cached is still the same.
>
> Link: https://bugzilla.suse.com/show_bug.cgi?id=1270397
> Signed-off-by: Qu Wenruo <wqu@suse.com>
> ---
> tests/generic/798 | 57 +++++++++++++++++++++++++++++++++++++++++++
> tests/generic/798.out | 2 ++
> 2 files changed, 59 insertions(+)
> create mode 100755 tests/generic/798
> create mode 100644 tests/generic/798.out
>
> diff --git a/tests/generic/798 b/tests/generic/798
> new file mode 100755
> index 00000000..4328475e
> --- /dev/null
> +++ b/tests/generic/798
> @@ -0,0 +1,57 @@
> +#! /bin/bash
> +# SPDX-License-Identifier: GPL-2.0
> +# Copyright (c) 2026 SUSE S.A. All Rights Reserved.
> +#
> +# FS QA Test 798
> +#
> +# Basic tests for cachestate()
> +#
> +. ./common/preamble
> +_begin_fstest auto quick
> +
> +_require_xfs_io_command "cachestat"
> +_require_scratch
> +
> +pagesize=$(_get_page_size)
> +
> +for num_page in 1 2 4 8 16; do
> + size=$(($pagesize * $num_page))
> +
> + echo "=== Test with $num_page pages ===" >> $seqres.full
> + _scratch_mkfs > /dev/null
> + _scratch_mount
> +
> + # Basic cached number reporting
> + $XFS_IO_PROG -f -c "pwrite -b $pagesize 0 $size" \
> + $SCRATCH_MNT/foobar >> $seqres.full
> + $XFS_IO_PROG -c "cachestat 0 $size" $SCRATCH_MNT/foobar > $tmp.output
> + cat $tmp.output >> $seqres.full
> + cached=$(cat $tmp.output | cut -f1 -d, | awk '{print $2}')
Use $AWK_PROG everywhere.
> + dirtied=$(cat $tmp.output | cut -f2 -d, | awk '{print $2}')
> +
> + if [ "$cached" -ne "$num_page" ]; then
> + _fail "cached not matching the page number"
> + fi
> +
> + if [ "$cached" -ne "$dirtied" ]; then
> + _fail "dirited not matching the page number"
> + fi
> + $XFS_IO_PROG -c "fsync" $SCRATCH_MNT/foobar >> $seqres.full
The redirection isn't needed; on success the fsync command sends
nothing to stdout.
Thanks.
> +
> + # Test dirty page number reporting after a fsync.
> + $XFS_IO_PROG -c "cachestat 0 $size" $SCRATCH_MNT/foobar > $tmp.output
> + cat $tmp.output >> $seqres.full
> + _scratch_unmount
> + cached=$(cat $tmp.output | cut -f1 -d, | awk '{print $2}')
> + dirtied=$(cat $tmp.output | cut -f2 -d, | awk '{print $2}')
> +
> + if [ "$cached" -ne "$num_page" ]; then
> + _fail "cached not matching the page number"
> + fi
> + if [ "$dirtied" -ne 0 ]; then
> + _fail "dirtied pages not zero"
> + fi
> +done
> +
> +echo "Silence is golden"
> +_exit 0
> diff --git a/tests/generic/798.out b/tests/generic/798.out
> new file mode 100644
> index 00000000..216d6e93
> --- /dev/null
> +++ b/tests/generic/798.out
> @@ -0,0 +1,2 @@
> +QA output created by 798
> +Silence is golden
> --
> 2.51.2
>
>
^ permalink raw reply [flat|nested] 5+ messages in thread
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2026-07-15 22:37 [PATCH] fstests: generic: add a basic cachestat test case Qu Wenruo
2026-07-16 10:05 ` Brian Foster
-- strict thread matches above, loose matches on Subject: below --
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2026-07-07 11:09 ` Anand Suveer Jain
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