* [PATCH] common/btrfs: handle dmdust as mounted device in _btrfs_buffered_read_on_mirror()
@ 2023-06-26 6:00 Qu Wenruo
2023-06-26 16:36 ` Filipe Manana
2023-06-26 17:32 ` Zorro Lang
0 siblings, 2 replies; 7+ messages in thread
From: Qu Wenruo @ 2023-06-26 6:00 UTC (permalink / raw)
To: linux-btrfs, fstests; +Cc: Filipe Manana
[BUG]
After commit ab41f0bddb73 ("common/btrfs: use _scratch_cycle_mount to
ensure all page caches are dropped"), the test case btrfs/143 can fail
like below:
btrfs/143 6s ... [failed, exit status 1]- output mismatch (see ~/xfstests/results//btrfs/143.out.bad)
--- tests/btrfs/143.out 2020-06-10 19:29:03.818519162 +0100
+++ ~/xfstests/results//btrfs/143.out.bad 2023-06-19 17:04:00.575033899 +0100
@@ -1,37 +1,6 @@
QA output created by 143
wrote 131072/131072 bytes
XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
-XXXXXXXX: aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa
................
-XXXXXXXX: aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa
................
-XXXXXXXX: aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa
................
-XXXXXXXX: aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa
................
[CAUSE]
Test case btrfs/143 uses dm-dust device to emulate read errors, this
means we can not use _scratch_cycle_mount to cycle mount $SCRATCH_MNT.
As it would go mount $SCRATCH_DEV, not the dm-dust device to
$SCRATCH_MNT.
This prevents us to trigger read-repair (since no error would be hit)
thus fail the test.
[FIX]
Since we can mount whatever device at $SCRATCH_MNT, we can not use
_scratch_cycle_mount in this case.
Instead implement a small helper to grab the mounted device and its
mount options, and use the same device and mount options to cycle
$SCRATCH_MNT mount.
This would fix btrfs/143 and hopefully future test cases which use dm
devices.
Reported-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
---
common/btrfs | 14 ++++++++++++--
1 file changed, 12 insertions(+), 2 deletions(-)
diff --git a/common/btrfs b/common/btrfs
index 175b33ae..4a02b2cc 100644
--- a/common/btrfs
+++ b/common/btrfs
@@ -601,8 +601,18 @@ _btrfs_buffered_read_on_mirror()
# The drop_caches doesn't seem to drop every pages on aarch64 with
# 64K page size.
# So here as another workaround, cycle mount the SCRATCH_MNT to ensure
- # the cache are dropped.
- _scratch_cycle_mount
+ # the cache are dropped, but we can not use _scratch_cycle_mount, as
+ # we may mount whatever dm device at SCRATCH_MNT.
+ # So here we grab the mounted block device and its mount options, then
+ # unmount and re-mount with the same device and options.
+ local mount_info=$(_mount | grep "$SCRATCH_MNT")
+ if [ -z "$mount_info" ]; then
+ _fail "failed to grab mount info of $SCRATCH_MNT"
+ fi
+ local dev=$(echo $mount_info | $AWK_PROG '{print $1}')
+ local opts=$(echo $mount_info | $AWK_PROG '{print $6}' | sed 's/[()]//g')
+ _scratch_unmount
+ _mount $dev -o $opts $SCRATCH_MNT
while [[ -z $( (( BASHPID % nr_mirrors == mirror )) &&
exec $XFS_IO_PROG \
-c "pread -b $size $offset $size" $file) ]]; do
--
2.39.0
^ permalink raw reply related [flat|nested] 7+ messages in thread* Re: [PATCH] common/btrfs: handle dmdust as mounted device in _btrfs_buffered_read_on_mirror() 2023-06-26 6:00 [PATCH] common/btrfs: handle dmdust as mounted device in _btrfs_buffered_read_on_mirror() Qu Wenruo @ 2023-06-26 16:36 ` Filipe Manana 2023-06-26 17:32 ` Zorro Lang 1 sibling, 0 replies; 7+ messages in thread From: Filipe Manana @ 2023-06-26 16:36 UTC (permalink / raw) To: Qu Wenruo; +Cc: linux-btrfs, fstests On Mon, Jun 26, 2023 at 7:05 AM Qu Wenruo <wqu@suse.com> wrote: > > [BUG] > After commit ab41f0bddb73 ("common/btrfs: use _scratch_cycle_mount to > ensure all page caches are dropped"), the test case btrfs/143 can fail > like below: > > btrfs/143 6s ... [failed, exit status 1]- output mismatch (see ~/xfstests/results//btrfs/143.out.bad) > --- tests/btrfs/143.out 2020-06-10 19:29:03.818519162 +0100 > +++ ~/xfstests/results//btrfs/143.out.bad 2023-06-19 17:04:00.575033899 +0100 > @@ -1,37 +1,6 @@ > QA output created by 143 > wrote 131072/131072 bytes > XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) > -XXXXXXXX: aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa > ................ > -XXXXXXXX: aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa > ................ > -XXXXXXXX: aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa > ................ > -XXXXXXXX: aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa > ................ > > [CAUSE] > Test case btrfs/143 uses dm-dust device to emulate read errors, this > means we can not use _scratch_cycle_mount to cycle mount $SCRATCH_MNT. > > As it would go mount $SCRATCH_DEV, not the dm-dust device to > $SCRATCH_MNT. > This prevents us to trigger read-repair (since no error would be hit) > thus fail the test. > > [FIX] > Since we can mount whatever device at $SCRATCH_MNT, we can not use > _scratch_cycle_mount in this case. > > Instead implement a small helper to grab the mounted device and its > mount options, and use the same device and mount options to cycle > $SCRATCH_MNT mount. > > This would fix btrfs/143 and hopefully future test cases which use dm > devices. > > Reported-by: Filipe Manana <fdmanana@suse.com> > Signed-off-by: Qu Wenruo <wqu@suse.com> Looks fine to me, and it works, so: Reviewed-by: Filipe Manana <fdmanana@suse.com> Thanks. > --- > common/btrfs | 14 ++++++++++++-- > 1 file changed, 12 insertions(+), 2 deletions(-) > > diff --git a/common/btrfs b/common/btrfs > index 175b33ae..4a02b2cc 100644 > --- a/common/btrfs > +++ b/common/btrfs > @@ -601,8 +601,18 @@ _btrfs_buffered_read_on_mirror() > # The drop_caches doesn't seem to drop every pages on aarch64 with > # 64K page size. > # So here as another workaround, cycle mount the SCRATCH_MNT to ensure > - # the cache are dropped. > - _scratch_cycle_mount > + # the cache are dropped, but we can not use _scratch_cycle_mount, as > + # we may mount whatever dm device at SCRATCH_MNT. > + # So here we grab the mounted block device and its mount options, then > + # unmount and re-mount with the same device and options. > + local mount_info=$(_mount | grep "$SCRATCH_MNT") > + if [ -z "$mount_info" ]; then > + _fail "failed to grab mount info of $SCRATCH_MNT" > + fi > + local dev=$(echo $mount_info | $AWK_PROG '{print $1}') > + local opts=$(echo $mount_info | $AWK_PROG '{print $6}' | sed 's/[()]//g') > + _scratch_unmount > + _mount $dev -o $opts $SCRATCH_MNT > while [[ -z $( (( BASHPID % nr_mirrors == mirror )) && > exec $XFS_IO_PROG \ > -c "pread -b $size $offset $size" $file) ]]; do > -- > 2.39.0 > ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] common/btrfs: handle dmdust as mounted device in _btrfs_buffered_read_on_mirror() 2023-06-26 6:00 [PATCH] common/btrfs: handle dmdust as mounted device in _btrfs_buffered_read_on_mirror() Qu Wenruo 2023-06-26 16:36 ` Filipe Manana @ 2023-06-26 17:32 ` Zorro Lang 2023-06-26 21:23 ` Qu Wenruo 1 sibling, 1 reply; 7+ messages in thread From: Zorro Lang @ 2023-06-26 17:32 UTC (permalink / raw) To: Qu Wenruo; +Cc: linux-btrfs, fstests, Filipe Manana On Mon, Jun 26, 2023 at 02:00:52PM +0800, Qu Wenruo wrote: > [BUG] > After commit ab41f0bddb73 ("common/btrfs: use _scratch_cycle_mount to > ensure all page caches are dropped"), the test case btrfs/143 can fail > like below: > > btrfs/143 6s ... [failed, exit status 1]- output mismatch (see ~/xfstests/results//btrfs/143.out.bad) > --- tests/btrfs/143.out 2020-06-10 19:29:03.818519162 +0100 > +++ ~/xfstests/results//btrfs/143.out.bad 2023-06-19 17:04:00.575033899 +0100 > @@ -1,37 +1,6 @@ > QA output created by 143 > wrote 131072/131072 bytes > XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) > -XXXXXXXX: aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa > ................ > -XXXXXXXX: aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa > ................ > -XXXXXXXX: aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa > ................ > -XXXXXXXX: aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa > ................ > > [CAUSE] > Test case btrfs/143 uses dm-dust device to emulate read errors, this > means we can not use _scratch_cycle_mount to cycle mount $SCRATCH_MNT. > > As it would go mount $SCRATCH_DEV, not the dm-dust device to > $SCRATCH_MNT. > This prevents us to trigger read-repair (since no error would be hit) > thus fail the test. > > [FIX] > Since we can mount whatever device at $SCRATCH_MNT, we can not use > _scratch_cycle_mount in this case. > > Instead implement a small helper to grab the mounted device and its > mount options, and use the same device and mount options to cycle > $SCRATCH_MNT mount. > > This would fix btrfs/143 and hopefully future test cases which use dm > devices. > > Reported-by: Filipe Manana <fdmanana@suse.com> > Signed-off-by: Qu Wenruo <wqu@suse.com> > --- > common/btrfs | 14 ++++++++++++-- > 1 file changed, 12 insertions(+), 2 deletions(-) > > diff --git a/common/btrfs b/common/btrfs > index 175b33ae..4a02b2cc 100644 > --- a/common/btrfs > +++ b/common/btrfs > @@ -601,8 +601,18 @@ _btrfs_buffered_read_on_mirror() > # The drop_caches doesn't seem to drop every pages on aarch64 with > # 64K page size. > # So here as another workaround, cycle mount the SCRATCH_MNT to ensure > - # the cache are dropped. > - _scratch_cycle_mount > + # the cache are dropped, but we can not use _scratch_cycle_mount, as > + # we may mount whatever dm device at SCRATCH_MNT. > + # So here we grab the mounted block device and its mount options, then > + # unmount and re-mount with the same device and options. > + local mount_info=$(_mount | grep "$SCRATCH_MNT") > + if [ -z "$mount_info" ]; then > + _fail "failed to grab mount info of $SCRATCH_MNT" > + fi > + local dev=$(echo $mount_info | $AWK_PROG '{print $1}') > + local opts=$(echo $mount_info | $AWK_PROG '{print $6}' | sed 's/[()]//g') The `findmnt` can help to get $dev and $opts: local dev=$(findmnt -n -T $SCRATCH_MNT -o SOURCE) local opts=$(findmnt -n -T $SCRATCH_MNT -o OPTIONS) If you hope to check you can keep: if [ -z "$dev" -o -z "$opts" ];then _fail "failed to grab mount info of $SCRATCH_MNT" fi > + _scratch_unmount > + _mount $dev -o $opts $SCRATCH_MNT I'm wondering can this help that, after you get the "real" device name: SCRATCH_DEV=$dev _scratch_cycle_mount Thanks, Zorro > while [[ -z $( (( BASHPID % nr_mirrors == mirror )) && > exec $XFS_IO_PROG \ > -c "pread -b $size $offset $size" $file) ]]; do > -- > 2.39.0 > ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] common/btrfs: handle dmdust as mounted device in _btrfs_buffered_read_on_mirror() 2023-06-26 17:32 ` Zorro Lang @ 2023-06-26 21:23 ` Qu Wenruo 2023-06-28 11:34 ` Zorro Lang 0 siblings, 1 reply; 7+ messages in thread From: Qu Wenruo @ 2023-06-26 21:23 UTC (permalink / raw) To: Zorro Lang, Qu Wenruo; +Cc: linux-btrfs, fstests, Filipe Manana On 2023/6/27 01:32, Zorro Lang wrote: > On Mon, Jun 26, 2023 at 02:00:52PM +0800, Qu Wenruo wrote: >> [BUG] >> After commit ab41f0bddb73 ("common/btrfs: use _scratch_cycle_mount to >> ensure all page caches are dropped"), the test case btrfs/143 can fail >> like below: >> >> btrfs/143 6s ... [failed, exit status 1]- output mismatch (see ~/xfstests/results//btrfs/143.out.bad) >> --- tests/btrfs/143.out 2020-06-10 19:29:03.818519162 +0100 >> +++ ~/xfstests/results//btrfs/143.out.bad 2023-06-19 17:04:00.575033899 +0100 >> @@ -1,37 +1,6 @@ >> QA output created by 143 >> wrote 131072/131072 bytes >> XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) >> -XXXXXXXX: aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa >> ................ >> -XXXXXXXX: aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa >> ................ >> -XXXXXXXX: aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa >> ................ >> -XXXXXXXX: aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa >> ................ >> >> [CAUSE] >> Test case btrfs/143 uses dm-dust device to emulate read errors, this >> means we can not use _scratch_cycle_mount to cycle mount $SCRATCH_MNT. >> >> As it would go mount $SCRATCH_DEV, not the dm-dust device to >> $SCRATCH_MNT. >> This prevents us to trigger read-repair (since no error would be hit) >> thus fail the test. >> >> [FIX] >> Since we can mount whatever device at $SCRATCH_MNT, we can not use >> _scratch_cycle_mount in this case. >> >> Instead implement a small helper to grab the mounted device and its >> mount options, and use the same device and mount options to cycle >> $SCRATCH_MNT mount. >> >> This would fix btrfs/143 and hopefully future test cases which use dm >> devices. >> >> Reported-by: Filipe Manana <fdmanana@suse.com> >> Signed-off-by: Qu Wenruo <wqu@suse.com> >> --- >> common/btrfs | 14 ++++++++++++-- >> 1 file changed, 12 insertions(+), 2 deletions(-) >> >> diff --git a/common/btrfs b/common/btrfs >> index 175b33ae..4a02b2cc 100644 >> --- a/common/btrfs >> +++ b/common/btrfs >> @@ -601,8 +601,18 @@ _btrfs_buffered_read_on_mirror() >> # The drop_caches doesn't seem to drop every pages on aarch64 with >> # 64K page size. >> # So here as another workaround, cycle mount the SCRATCH_MNT to ensure >> - # the cache are dropped. >> - _scratch_cycle_mount >> + # the cache are dropped, but we can not use _scratch_cycle_mount, as >> + # we may mount whatever dm device at SCRATCH_MNT. >> + # So here we grab the mounted block device and its mount options, then >> + # unmount and re-mount with the same device and options. >> + local mount_info=$(_mount | grep "$SCRATCH_MNT") >> + if [ -z "$mount_info" ]; then >> + _fail "failed to grab mount info of $SCRATCH_MNT" >> + fi >> + local dev=$(echo $mount_info | $AWK_PROG '{print $1}') >> + local opts=$(echo $mount_info | $AWK_PROG '{print $6}' | sed 's/[()]//g') > > The `findmnt` can help to get $dev and $opts: > > local dev=$(findmnt -n -T $SCRATCH_MNT -o SOURCE) > local opts=$(findmnt -n -T $SCRATCH_MNT -o OPTIONS) > > If you hope to check you can keep: > > if [ -z "$dev" -o -z "$opts" ];then > _fail "failed to grab mount info of $SCRATCH_MNT" > fi That's really helpful! > >> + _scratch_unmount >> + _mount $dev -o $opts $SCRATCH_MNT > > I'm wondering can this help that, after you get the "real" device name: > > SCRATCH_DEV=$dev _scratch_cycle_mount AFAIK we still need to specify the mount option. As it's possible previous mount is specifying certain mount option that's not in MOUNT_OPTIONS environment variables. E.g. mounting a specific subvolume or a temporary mount option. Thus I believe we may still need to specific the mount options. Thanks, Qu > > Thanks, > Zorro > >> while [[ -z $( (( BASHPID % nr_mirrors == mirror )) && >> exec $XFS_IO_PROG \ >> -c "pread -b $size $offset $size" $file) ]]; do >> -- >> 2.39.0 >> > ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] common/btrfs: handle dmdust as mounted device in _btrfs_buffered_read_on_mirror() 2023-06-26 21:23 ` Qu Wenruo @ 2023-06-28 11:34 ` Zorro Lang 2023-06-28 11:40 ` Qu Wenruo 0 siblings, 1 reply; 7+ messages in thread From: Zorro Lang @ 2023-06-28 11:34 UTC (permalink / raw) To: Qu Wenruo; +Cc: Qu Wenruo, linux-btrfs, fstests, Filipe Manana On Tue, Jun 27, 2023 at 05:23:31AM +0800, Qu Wenruo wrote: > > > On 2023/6/27 01:32, Zorro Lang wrote: > > On Mon, Jun 26, 2023 at 02:00:52PM +0800, Qu Wenruo wrote: > > > [BUG] > > > After commit ab41f0bddb73 ("common/btrfs: use _scratch_cycle_mount to > > > ensure all page caches are dropped"), the test case btrfs/143 can fail > > > like below: > > > > > > btrfs/143 6s ... [failed, exit status 1]- output mismatch (see ~/xfstests/results//btrfs/143.out.bad) > > > --- tests/btrfs/143.out 2020-06-10 19:29:03.818519162 +0100 > > > +++ ~/xfstests/results//btrfs/143.out.bad 2023-06-19 17:04:00.575033899 +0100 > > > @@ -1,37 +1,6 @@ > > > QA output created by 143 > > > wrote 131072/131072 bytes > > > XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) > > > -XXXXXXXX: aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa > > > ................ > > > -XXXXXXXX: aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa > > > ................ > > > -XXXXXXXX: aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa > > > ................ > > > -XXXXXXXX: aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa > > > ................ > > > > > > [CAUSE] > > > Test case btrfs/143 uses dm-dust device to emulate read errors, this > > > means we can not use _scratch_cycle_mount to cycle mount $SCRATCH_MNT. > > > > > > As it would go mount $SCRATCH_DEV, not the dm-dust device to > > > $SCRATCH_MNT. > > > This prevents us to trigger read-repair (since no error would be hit) > > > thus fail the test. > > > > > > [FIX] > > > Since we can mount whatever device at $SCRATCH_MNT, we can not use > > > _scratch_cycle_mount in this case. > > > > > > Instead implement a small helper to grab the mounted device and its > > > mount options, and use the same device and mount options to cycle > > > $SCRATCH_MNT mount. > > > > > > This would fix btrfs/143 and hopefully future test cases which use dm > > > devices. > > > > > > Reported-by: Filipe Manana <fdmanana@suse.com> > > > Signed-off-by: Qu Wenruo <wqu@suse.com> > > > --- > > > common/btrfs | 14 ++++++++++++-- > > > 1 file changed, 12 insertions(+), 2 deletions(-) > > > > > > diff --git a/common/btrfs b/common/btrfs > > > index 175b33ae..4a02b2cc 100644 > > > --- a/common/btrfs > > > +++ b/common/btrfs > > > @@ -601,8 +601,18 @@ _btrfs_buffered_read_on_mirror() > > > # The drop_caches doesn't seem to drop every pages on aarch64 with > > > # 64K page size. > > > # So here as another workaround, cycle mount the SCRATCH_MNT to ensure > > > - # the cache are dropped. > > > - _scratch_cycle_mount > > > + # the cache are dropped, but we can not use _scratch_cycle_mount, as > > > + # we may mount whatever dm device at SCRATCH_MNT. > > > + # So here we grab the mounted block device and its mount options, then > > > + # unmount and re-mount with the same device and options. > > > + local mount_info=$(_mount | grep "$SCRATCH_MNT") > > > + if [ -z "$mount_info" ]; then > > > + _fail "failed to grab mount info of $SCRATCH_MNT" > > > + fi > > > + local dev=$(echo $mount_info | $AWK_PROG '{print $1}') > > > + local opts=$(echo $mount_info | $AWK_PROG '{print $6}' | sed 's/[()]//g') > > > > The `findmnt` can help to get $dev and $opts: > > > > local dev=$(findmnt -n -T $SCRATCH_MNT -o SOURCE) > > local opts=$(findmnt -n -T $SCRATCH_MNT -o OPTIONS) > > > > If you hope to check you can keep: > > > > if [ -z "$dev" -o -z "$opts" ];then > > _fail "failed to grab mount info of $SCRATCH_MNT" > > fi > > That's really helpful! > > > > > > + _scratch_unmount > > > + _mount $dev -o $opts $SCRATCH_MNT > > > > I'm wondering can this help that, after you get the "real" device name: > > > > SCRATCH_DEV=$dev _scratch_cycle_mount > > AFAIK we still need to specify the mount option. > > As it's possible previous mount is specifying certain mount option > that's not in MOUNT_OPTIONS environment variables. > > E.g. mounting a specific subvolume or a temporary mount option. > > Thus I believe we may still need to specific the mount options. Hmm... if the _scratch_cycle_mount doesn't support dmdust, others dmxxxx (e.g. dmdelay, dmthin, dmerror, dmflaky) have similar problem, right? Thanks, Zorro > > Thanks, > Qu > > > > > Thanks, > > Zorro > > > > > while [[ -z $( (( BASHPID % nr_mirrors == mirror )) && > > > exec $XFS_IO_PROG \ > > > -c "pread -b $size $offset $size" $file) ]]; do > > > -- > > > 2.39.0 > > > > > > ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] common/btrfs: handle dmdust as mounted device in _btrfs_buffered_read_on_mirror() 2023-06-28 11:34 ` Zorro Lang @ 2023-06-28 11:40 ` Qu Wenruo 2023-06-28 15:16 ` Zorro Lang 0 siblings, 1 reply; 7+ messages in thread From: Qu Wenruo @ 2023-06-28 11:40 UTC (permalink / raw) To: Zorro Lang; +Cc: Qu Wenruo, linux-btrfs, fstests, Filipe Manana On 2023/6/28 19:34, Zorro Lang wrote: > On Tue, Jun 27, 2023 at 05:23:31AM +0800, Qu Wenruo wrote: >> >> >> On 2023/6/27 01:32, Zorro Lang wrote: >>> On Mon, Jun 26, 2023 at 02:00:52PM +0800, Qu Wenruo wrote: >>>> [BUG] >>>> After commit ab41f0bddb73 ("common/btrfs: use _scratch_cycle_mount to >>>> ensure all page caches are dropped"), the test case btrfs/143 can fail >>>> like below: >>>> >>>> btrfs/143 6s ... [failed, exit status 1]- output mismatch (see ~/xfstests/results//btrfs/143.out.bad) >>>> --- tests/btrfs/143.out 2020-06-10 19:29:03.818519162 +0100 >>>> +++ ~/xfstests/results//btrfs/143.out.bad 2023-06-19 17:04:00.575033899 +0100 >>>> @@ -1,37 +1,6 @@ >>>> QA output created by 143 >>>> wrote 131072/131072 bytes >>>> XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) >>>> -XXXXXXXX: aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa >>>> ................ >>>> -XXXXXXXX: aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa >>>> ................ >>>> -XXXXXXXX: aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa >>>> ................ >>>> -XXXXXXXX: aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa >>>> ................ >>>> >>>> [CAUSE] >>>> Test case btrfs/143 uses dm-dust device to emulate read errors, this >>>> means we can not use _scratch_cycle_mount to cycle mount $SCRATCH_MNT. >>>> >>>> As it would go mount $SCRATCH_DEV, not the dm-dust device to >>>> $SCRATCH_MNT. >>>> This prevents us to trigger read-repair (since no error would be hit) >>>> thus fail the test. >>>> >>>> [FIX] >>>> Since we can mount whatever device at $SCRATCH_MNT, we can not use >>>> _scratch_cycle_mount in this case. >>>> >>>> Instead implement a small helper to grab the mounted device and its >>>> mount options, and use the same device and mount options to cycle >>>> $SCRATCH_MNT mount. >>>> >>>> This would fix btrfs/143 and hopefully future test cases which use dm >>>> devices. >>>> >>>> Reported-by: Filipe Manana <fdmanana@suse.com> >>>> Signed-off-by: Qu Wenruo <wqu@suse.com> >>>> --- >>>> common/btrfs | 14 ++++++++++++-- >>>> 1 file changed, 12 insertions(+), 2 deletions(-) >>>> >>>> diff --git a/common/btrfs b/common/btrfs >>>> index 175b33ae..4a02b2cc 100644 >>>> --- a/common/btrfs >>>> +++ b/common/btrfs >>>> @@ -601,8 +601,18 @@ _btrfs_buffered_read_on_mirror() >>>> # The drop_caches doesn't seem to drop every pages on aarch64 with >>>> # 64K page size. >>>> # So here as another workaround, cycle mount the SCRATCH_MNT to ensure >>>> - # the cache are dropped. >>>> - _scratch_cycle_mount >>>> + # the cache are dropped, but we can not use _scratch_cycle_mount, as >>>> + # we may mount whatever dm device at SCRATCH_MNT. >>>> + # So here we grab the mounted block device and its mount options, then >>>> + # unmount and re-mount with the same device and options. >>>> + local mount_info=$(_mount | grep "$SCRATCH_MNT") >>>> + if [ -z "$mount_info" ]; then >>>> + _fail "failed to grab mount info of $SCRATCH_MNT" >>>> + fi >>>> + local dev=$(echo $mount_info | $AWK_PROG '{print $1}') >>>> + local opts=$(echo $mount_info | $AWK_PROG '{print $6}' | sed 's/[()]//g') >>> >>> The `findmnt` can help to get $dev and $opts: >>> >>> local dev=$(findmnt -n -T $SCRATCH_MNT -o SOURCE) >>> local opts=$(findmnt -n -T $SCRATCH_MNT -o OPTIONS) >>> >>> If you hope to check you can keep: >>> >>> if [ -z "$dev" -o -z "$opts" ];then >>> _fail "failed to grab mount info of $SCRATCH_MNT" >>> fi >> >> That's really helpful! >> >>> >>>> + _scratch_unmount >>>> + _mount $dev -o $opts $SCRATCH_MNT >>> >>> I'm wondering can this help that, after you get the "real" device name: >>> >>> SCRATCH_DEV=$dev _scratch_cycle_mount >> >> AFAIK we still need to specify the mount option. >> >> As it's possible previous mount is specifying certain mount option >> that's not in MOUNT_OPTIONS environment variables. >> >> E.g. mounting a specific subvolume or a temporary mount option. >> >> Thus I believe we may still need to specific the mount options. > > Hmm... if the _scratch_cycle_mount doesn't support dmdust, others dmxxxx > (e.g. dmdelay, dmthin, dmerror, dmflaky) have similar problem, right? Yes, but my point here is, although "SCRATCH_DEV=$dev _scratch_cycle_mount" can work for most cases, it can still miss the specific mount option of the current mount. Thus we still need to go "_mount $dev -o $opts $SCRATCH_MNT", just for the extra mount options. Thanks, Qu > > Thanks, > Zorro > >> >> Thanks, >> Qu >> >>> >>> Thanks, >>> Zorro >>> >>>> while [[ -z $( (( BASHPID % nr_mirrors == mirror )) && >>>> exec $XFS_IO_PROG \ >>>> -c "pread -b $size $offset $size" $file) ]]; do >>>> -- >>>> 2.39.0 >>>> >>> >> > ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] common/btrfs: handle dmdust as mounted device in _btrfs_buffered_read_on_mirror() 2023-06-28 11:40 ` Qu Wenruo @ 2023-06-28 15:16 ` Zorro Lang 0 siblings, 0 replies; 7+ messages in thread From: Zorro Lang @ 2023-06-28 15:16 UTC (permalink / raw) To: Qu Wenruo; +Cc: Qu Wenruo, linux-btrfs, fstests, Filipe Manana On Wed, Jun 28, 2023 at 07:40:14PM +0800, Qu Wenruo wrote: > > > On 2023/6/28 19:34, Zorro Lang wrote: > > On Tue, Jun 27, 2023 at 05:23:31AM +0800, Qu Wenruo wrote: > > > > > > > > > On 2023/6/27 01:32, Zorro Lang wrote: > > > > On Mon, Jun 26, 2023 at 02:00:52PM +0800, Qu Wenruo wrote: > > > > > [BUG] > > > > > After commit ab41f0bddb73 ("common/btrfs: use _scratch_cycle_mount to > > > > > ensure all page caches are dropped"), the test case btrfs/143 can fail > > > > > like below: > > > > > > > > > > btrfs/143 6s ... [failed, exit status 1]- output mismatch (see ~/xfstests/results//btrfs/143.out.bad) > > > > > --- tests/btrfs/143.out 2020-06-10 19:29:03.818519162 +0100 > > > > > +++ ~/xfstests/results//btrfs/143.out.bad 2023-06-19 17:04:00.575033899 +0100 > > > > > @@ -1,37 +1,6 @@ > > > > > QA output created by 143 > > > > > wrote 131072/131072 bytes > > > > > XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) > > > > > -XXXXXXXX: aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa > > > > > ................ > > > > > -XXXXXXXX: aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa > > > > > ................ > > > > > -XXXXXXXX: aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa > > > > > ................ > > > > > -XXXXXXXX: aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa > > > > > ................ > > > > > > > > > > [CAUSE] > > > > > Test case btrfs/143 uses dm-dust device to emulate read errors, this > > > > > means we can not use _scratch_cycle_mount to cycle mount $SCRATCH_MNT. > > > > > > > > > > As it would go mount $SCRATCH_DEV, not the dm-dust device to > > > > > $SCRATCH_MNT. > > > > > This prevents us to trigger read-repair (since no error would be hit) > > > > > thus fail the test. > > > > > > > > > > [FIX] > > > > > Since we can mount whatever device at $SCRATCH_MNT, we can not use > > > > > _scratch_cycle_mount in this case. > > > > > > > > > > Instead implement a small helper to grab the mounted device and its > > > > > mount options, and use the same device and mount options to cycle > > > > > $SCRATCH_MNT mount. > > > > > > > > > > This would fix btrfs/143 and hopefully future test cases which use dm > > > > > devices. > > > > > > > > > > Reported-by: Filipe Manana <fdmanana@suse.com> > > > > > Signed-off-by: Qu Wenruo <wqu@suse.com> > > > > > --- > > > > > common/btrfs | 14 ++++++++++++-- > > > > > 1 file changed, 12 insertions(+), 2 deletions(-) > > > > > > > > > > diff --git a/common/btrfs b/common/btrfs > > > > > index 175b33ae..4a02b2cc 100644 > > > > > --- a/common/btrfs > > > > > +++ b/common/btrfs > > > > > @@ -601,8 +601,18 @@ _btrfs_buffered_read_on_mirror() > > > > > # The drop_caches doesn't seem to drop every pages on aarch64 with > > > > > # 64K page size. > > > > > # So here as another workaround, cycle mount the SCRATCH_MNT to ensure > > > > > - # the cache are dropped. > > > > > - _scratch_cycle_mount > > > > > + # the cache are dropped, but we can not use _scratch_cycle_mount, as > > > > > + # we may mount whatever dm device at SCRATCH_MNT. > > > > > + # So here we grab the mounted block device and its mount options, then > > > > > + # unmount and re-mount with the same device and options. > > > > > + local mount_info=$(_mount | grep "$SCRATCH_MNT") > > > > > + if [ -z "$mount_info" ]; then > > > > > + _fail "failed to grab mount info of $SCRATCH_MNT" > > > > > + fi > > > > > + local dev=$(echo $mount_info | $AWK_PROG '{print $1}') > > > > > + local opts=$(echo $mount_info | $AWK_PROG '{print $6}' | sed 's/[()]//g') > > > > > > > > The `findmnt` can help to get $dev and $opts: > > > > > > > > local dev=$(findmnt -n -T $SCRATCH_MNT -o SOURCE) > > > > local opts=$(findmnt -n -T $SCRATCH_MNT -o OPTIONS) > > > > > > > > If you hope to check you can keep: > > > > > > > > if [ -z "$dev" -o -z "$opts" ];then > > > > _fail "failed to grab mount info of $SCRATCH_MNT" > > > > fi > > > > > > That's really helpful! > > > > > > > > > > > > + _scratch_unmount > > > > > + _mount $dev -o $opts $SCRATCH_MNT > > > > > > > > I'm wondering can this help that, after you get the "real" device name: > > > > > > > > SCRATCH_DEV=$dev _scratch_cycle_mount > > > > > > AFAIK we still need to specify the mount option. > > > > > > As it's possible previous mount is specifying certain mount option > > > that's not in MOUNT_OPTIONS environment variables. > > > > > > E.g. mounting a specific subvolume or a temporary mount option. > > > > > > Thus I believe we may still need to specific the mount options. > > > > Hmm... if the _scratch_cycle_mount doesn't support dmdust, others dmxxxx > > (e.g. dmdelay, dmthin, dmerror, dmflaky) have similar problem, right? > > Yes, but my point here is, although "SCRATCH_DEV=$dev > _scratch_cycle_mount" can work for most cases, it can still miss the > specific mount option of the current mount. > > Thus we still need to go "_mount $dev -o $opts $SCRATCH_MNT", just for > the extra mount options. OK, let's merge this patch to fix this small regression issue at first. Then I'll think about how to make _scratch_cycle_mount work with dmXXXX in another patch. Please send a V2 to use findmnt, I'll merge it in next fstests release. Thanks, Zorro > > Thanks, > Qu > > > > Thanks, > > Zorro > > > > > > > > Thanks, > > > Qu > > > > > > > > > > > Thanks, > > > > Zorro > > > > > > > > > while [[ -z $( (( BASHPID % nr_mirrors == mirror )) && > > > > > exec $XFS_IO_PROG \ > > > > > -c "pread -b $size $offset $size" $file) ]]; do > > > > > -- > > > > > 2.39.0 > > > > > > > > > > > > > > > ^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2023-06-28 15:18 UTC | newest] Thread overview: 7+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2023-06-26 6:00 [PATCH] common/btrfs: handle dmdust as mounted device in _btrfs_buffered_read_on_mirror() Qu Wenruo 2023-06-26 16:36 ` Filipe Manana 2023-06-26 17:32 ` Zorro Lang 2023-06-26 21:23 ` Qu Wenruo 2023-06-28 11:34 ` Zorro Lang 2023-06-28 11:40 ` Qu Wenruo 2023-06-28 15:16 ` Zorro Lang
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