| Message ID | 20230629001010.36235-1-wqu@suse.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2] common/btrfs: handle dmdust as mounted device in _btrfs_buffered_read_on_mirror() | expand |
On Thu, Jun 29, 2023 at 08:10:10AM +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> > Reviewed-by: Filipe Manana <fdmanana@suse.com> > Signed-off-by: Qu Wenruo <wqu@suse.com> > --- > Changelog: > v2: > - Use findmnt command to grab mount options and source device > --- This version looks good to me. Although the "_mount $dev -o $opts $SCRATCH_MNT" is a little odd, but as this's a btrfs only helper, so I think it's fine for btrfs at least. Reviewed-by: Zorro Lang <zlang@redhat.com> > common/btrfs | 13 +++++++++++-- > 1 file changed, 11 insertions(+), 2 deletions(-) > > diff --git a/common/btrfs b/common/btrfs > index 175b33ae..0fec093d 100644 > --- a/common/btrfs > +++ b/common/btrfs > @@ -601,8 +601,17 @@ _btrfs_buffered_read_on_mirror() > # The drop_caches doesn't seem to drop every pages on aarch64 with > # 64K page size. > # So here as another workaround, cycle mount the SCRATCH_MNT to ensure > - # the cache are dropped. > - _scratch_cycle_mount > + # the cache are dropped, but we can not use _scratch_cycle_mount, as > + # we may mount whatever dm device at SCRATCH_MNT. > + # So here we grab the mounted block device and its mount options, then > + # unmount and re-mount with the same device and options. > + local dev=$(findmnt -n -T $SCRATCH_MNT -o SOURCE) > + local opts=$(findmnt -n -T $SCRATCH_MNT -o OPTIONS) > + if [ -z "$dev" -o -z "$opts" ]; then > + _fail "failed to grab mount info of $SCRATCH_MNT" > + fi > + _scratch_unmount > + _mount $dev -o $opts $SCRATCH_MNT > while [[ -z $( (( BASHPID % nr_mirrors == mirror )) && > exec $XFS_IO_PROG \ > -c "pread -b $size $offset $size" $file) ]]; do > -- > 2.39.0 >
diff --git a/common/btrfs b/common/btrfs index 175b33ae..0fec093d 100644 --- a/common/btrfs +++ b/common/btrfs @@ -601,8 +601,17 @@ _btrfs_buffered_read_on_mirror() # The drop_caches doesn't seem to drop every pages on aarch64 with # 64K page size. # So here as another workaround, cycle mount the SCRATCH_MNT to ensure - # the cache are dropped. - _scratch_cycle_mount + # the cache are dropped, but we can not use _scratch_cycle_mount, as + # we may mount whatever dm device at SCRATCH_MNT. + # So here we grab the mounted block device and its mount options, then + # unmount and re-mount with the same device and options. + local dev=$(findmnt -n -T $SCRATCH_MNT -o SOURCE) + local opts=$(findmnt -n -T $SCRATCH_MNT -o OPTIONS) + if [ -z "$dev" -o -z "$opts" ]; then + _fail "failed to grab mount info of $SCRATCH_MNT" + fi + _scratch_unmount + _mount $dev -o $opts $SCRATCH_MNT while [[ -z $( (( BASHPID % nr_mirrors == mirror )) && exec $XFS_IO_PROG \ -c "pread -b $size $offset $size" $file) ]]; do
[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> Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Qu Wenruo <wqu@suse.com> --- Changelog: v2: - Use findmnt command to grab mount options and source device --- common/btrfs | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-)