2022-08-01 15:16:25

by Zorro Lang

[permalink] [raw]
Subject: Re: [PATCH 2/2] dmerror: support external log and realtime devices

On Mon, Aug 01, 2022 at 02:10:12AM +0800, Zorro Lang wrote:
> On Sun, Jul 31, 2022 at 09:48:19AM -0700, Darrick J. Wong wrote:
> > On Sat, Jul 30, 2022 at 06:18:34PM +0800, Zorro Lang wrote:
> > > On Tue, Jul 26, 2022 at 12:48:42PM -0700, Darrick J. Wong wrote:
> > > > From: Darrick J. Wong <[email protected]>
> > > >
> > > > Upgrade the dmerror code to coordinate making external scratch log and
> > > > scratch realtime devices error out along with the scratch device. Note
> > > > that unlike SCRATCH_DEV, we save the old rt/log devices in a separate
> > > > variable and overwrite SCRATCH_{RT,LOG}DEV so that all the helper
> > > > functions continue to work properly.
> > > >
> > > > This is very similar to what we did for dm-flakey a while back.
> > > >
> > > > Signed-off-by: Darrick J. Wong <[email protected]>
> > > > ---
> > >
> > > Hi Darrick,
> > >
> > > I'll merge the patch 1/2 this week, but this 2/2 looks like bring in new
> > > failures on ext4 with local.config as [0], for example[1], which is passed[2]
> > > without this patch. It's fine on Btrfs and xfs for me.
> > >
> > > Thanks,
> > > Zorro
> > >
> > > [0]
> > > export TEST_DEV=/dev/sda5
> > > export TEST_DIR=/mnt/test
> > > export SCRATCH_DEV=/dev/sda3
> > > export SCRATCH_MNT=/mnt/scratch
> > > export USE_EXTERNAL=yes
> > > export SCRATCH_LOGDEV=/dev/loop0
> > >
> > > [1]
> > > generic/338 4s ... - output mismatch (see /root/git/xfstests/results//logdev/generic/338.out.bad)
> > > --- tests/generic/338.out 2022-04-29 23:07:23.330499055 +0800
> > > +++ /root/git/xfstests/results//logdev/generic/338.out.bad 2022-07-30 18:01:41.900765965 +0800
> > > @@ -1,2 +1,4 @@
> > > QA output created by 338
> > > Silence is golden
> > > +mount: /mnt/scratch: wrong fs type, bad option, bad superblock on /dev/mapper/error-test, missing codepage or helper program, or other error.
> > > + dmesg(1) may have more information after failed mount system call.
> >
> > Hmm, any chance you could post the dmesg that goes with this?
>
> Sure, [1] is the dmesg with this patch. [2] is the dmesg without this patch.

Hi Darrick,

I think I know why it fails, but I don't know how to deal with it offically :)
So cc [email protected] list.

By testing, it fails after /dev/mapper/error-logtest be created. If we keep
SCRATCH_LOGDEV no change, everything is fine for ext4. Or you need to use
"-o journal_path=..." or "-o journal_dev=..." to specify the new journal device
path. Or you have to re-make ext4 with "-J device=/dev/mapper/error-logtest".

See below example:

1) ext4 extranal log device works:
# mke2fs -O journal_dev /dev/loop0
# mkfs.ext4 -F /dev/sda3 -J device=/dev/loop0
# mount /dev/sda3 /mnt/scratch/
# umount /mnt/scratch

2) Still works if only create error-test, don't touch LOGDEV:
# dmsetup create error-test --table "0 104849408 linear /dev/sda3 0"
# mount /dev/mapper/error-test /mnt/scratch/
# umount /mnt/scratch

3) Fails if you create error-logtest ...:
# dmsetup create error-logtest --table "0 2097152 linear /dev/loop0 0"
# mount /dev/mapper/error-test /mnt/scratch/
mount: /mnt/scratch: wrong fs type, bad option, bad superblock on /dev/mapper/error-test, missing codepage or helper program, or other error.
dmesg(1) may have more information after failed mount system call.

4) ... Except you specify the new logdev path by mount option:
# ls /dev/mapper/error-logtest -l
lrwxrwxrwx. 1 root root 7 Aug 1 22:28 /dev/mapper/error-logtest -> ../dm-7
# mount /dev/mapper/error-test /mnt/scratch/ -o journal_path=/dev/dm-7
# umount /mnt/scratch

5) And after step 4, I can mount /dev/mapper/error-test again ...
# mount /dev/mapper/error-test /mnt/scratch
# umount /mnt/scratch

I'm not an expert of ext4, that's only my test result, hope to get a clear
explanation for that :)

Thanks,
Zorro

>
> Thanks,
> Zorro
>
> [1]
> # ./check -s logdev generic/338
> SECTION -- logdev
> FSTYP -- ext4
> PLATFORM -- Linux/x86_64 hp-dl380pg8-01 5.19.0-0.rc2.21.fc37.x86_64+debug #1 SMP PREEMPT_DYNAMIC Mon Jun 13 14:55:18 UTC 2022
> MKFS_OPTIONS -- /dev/sda3
> MOUNT_OPTIONS -- -o acl,user_xattr -o context=system_u:object_r:root_t:s0 /dev/sda3 /mnt/scratch
>
> generic/338 5s ... - output mismatch (see /root/git/xfstests/results//logdev/generic/338.out.bad)
> --- tests/generic/338.out 2022-04-29 23:07:23.330499055 +0800
> +++ /root/git/xfstests/results//logdev/generic/338.out.bad 2022-08-01 02:00:17.284965956 +0800
> @@ -1,2 +1,4 @@
> QA output created by 338
> Silence is golden
> +mount: /mnt/scratch: wrong fs type, bad option, bad superblock on /dev/mapper/error-test, missing codepage or helper program, or other error.
> + dmesg(1) may have more information after failed mount system call.
> ...
> (Run 'diff -u /root/git/xfstests/tests/generic/338.out /root/git/xfstests/results//logdev/generic/338.out.bad' to see the entire diff)
> Ran: generic/338
> Failures: generic/338
> Failed 1 of 1 tests
>
> # dmesg
> [1382503.819432] run fstests generic/338 at 2022-08-01 02:00:13
> [1382504.957989] EXT4-fs (dm-6): failed to open journal device unknown-block(7,0) -16
> [1382504.987712] Buffer I/O error on dev dm-7, logical block 262128, async page read
> [1382505.009371] Buffer I/O error on dev dm-6, logical block 13106160, async page read
> [1382506.576023] 338 (277855): drop_caches: 3
> [1382507.440513] EXT4-fs (sda5): unmounting filesystem.
>
> [2]
> # ./check -s logdev generic/338
> SECTION -- logdev
> FSTYP -- ext4
> PLATFORM -- Linux/x86_64 hp-dl380pg8-01 5.19.0-0.rc2.21.fc37.x86_64+debug #1 SMP PREEMPT_DYNAMIC Mon Jun 13 14:55:18 UTC 2022
> MKFS_OPTIONS -- /dev/sda3
> MOUNT_OPTIONS -- -o acl,user_xattr -o context=system_u:object_r:root_t:s0 /dev/sda3 /mnt/scratch
>
> generic/338 5s ... 3s
> Ran: generic/338
> Passed all 1 tests
>
> # dmesg
> [1382877.411459] run fstests generic/338 at 2022-08-01 02:06:27
> [1382878.778539] EXT4-fs (dm-6): mounted filesystem with ordered data mode. Quota mode: none.
> [1382878.803639] Buffer I/O error on dev dm-6, logical block 13106160, async page read
> [1382878.951444] 338 (279660): drop_caches: 3
> [1382879.421933] EXT4-fs warning (device dm-6): htree_dirblock_to_tree:1044: inode #2: lblock 0: comm ls: error -5 reading directory block
> [1382879.422007] EXT4-fs error (device dm-6): ext4_get_inode_loc:4587: inode #2: block 1064: comm ls: unable to read itable block
> [1382879.422026] EXT4-fs error (device dm-6) in ext4_reserve_inode_write:5756: IO failure
> [1382879.422031] EXT4-fs error (device dm-6): ext4_dirty_inode:5952: inode #2: comm ls: mark_inode_dirty error
> [1382879.750038] EXT4-fs error (device dm-6): __ext4_find_entry:1635: inode #2: comm xfs_io: reading directory lblock 0
> [1382880.180381] Buffer I/O error on dev dm-6, logical block 0, lost async page write
> [1382880.180961] EXT4-fs (dm-6): unmounting filesystem.
> [1382880.181541] Aborting journal on device loop0.
> [1382880.182777] EXT4-fs error (device dm-6): ext4_put_super:1229: comm umount: Couldn't clean up the journal
> [1382880.182798] EXT4-fs (dm-6): previous I/O error to superblock detected
> [1382880.182817] Buffer I/O error on dev dm-6, logical block 0, lost sync page write
> [1382880.182860] EXT4-fs (dm-6): I/O error while writing superblock
> [1382880.182867] EXT4-fs (dm-6): Remounting filesystem read-only
> [1382880.742572] EXT4-fs (sda5): unmounting filesystem.
>
> >
> > --D
> >
> > > ...
> > > (Run 'diff -u /root/git/xfstests/tests/generic/338.out /root/git/xfstests/results//logdev/generic/338.out.bad' to see the entire diff)
> > > generic/441 5s ... - output mismatch (see /root/git/xfstests/results//logdev/generic/441.out.bad)
> > > --- tests/generic/441.out 2022-04-29 23:07:23.406499916 +0800
> > > +++ /root/git/xfstests/results//logdev/generic/441.out.bad 2022-07-30 18:01:46.829822438 +0800
> > > @@ -1,3 +1,6 @@
> > > QA output created by 441
> > > Format and mount
> > > -Test passed!
> > > +mount: /mnt/scratch: wrong fs type, bad option, bad superblock on /dev/mapper/error-test, missing codepage or helper program, or other error.
> > > + dmesg(1) may have more information after failed mount system call.
> > > +Success on second fsync on fd[0]!
> > > +umount: /mnt/scratch: not mounted.
> > > ...
> > > (Run 'diff -u /root/git/xfstests/tests/generic/441.out /root/git/xfstests/results//logdev/generic/441.out.bad' to see the entire diff)
> > >
> > > [2]
> > > generic/338 4s ... 5s
> > > generic/441 5s ... 5s
> > > generic/442 3s ... 3s
> > >
> > >
> > > > common/dmerror | 159 +++++++++++++++++++++++++++++++++++++++++++++++++++--
> > > > tests/generic/441 | 2 -
> > > > tests/generic/487 | 2 -
> > > > 3 files changed, 156 insertions(+), 7 deletions(-)
> > > >
> > > >
> > > > diff --git a/common/dmerror b/common/dmerror
> > > > index 01a4c8b5..85ef9a16 100644
> > > > --- a/common/dmerror
> > > > +++ b/common/dmerror
> > > > @@ -4,25 +4,88 @@
> > > > #
> > > > # common functions for setting up and tearing down a dmerror device
> > > >
> > > > +_dmerror_setup_vars()
> > > > +{
> > > > + local backing_dev="$1"
> > > > + local tag="$2"
> > > > + local target="$3"
> > > > +
> > > > + test -z "$target" && target=error
> > > > + local blk_dev_size=$(blockdev --getsz "$backing_dev")
> > > > +
> > > > + eval export "DMLINEAR_${tag}TABLE=\"0 $blk_dev_size linear $backing_dev 0\""
> > > > + eval export "DMERROR_${tag}TABLE=\"0 $blk_dev_size $target $backing_dev 0\""
> > > > +}
> > > > +
> > > > _dmerror_setup()
> > > > {
> > > > - local dm_backing_dev=$SCRATCH_DEV
> > > > + local rt_target=
> > > > + local linear_target=
> > > >
> > > > - local blk_dev_size=`blockdev --getsz $dm_backing_dev`
> > > > + for arg in "[email protected]"; do
> > > > + case "${arg}" in
> > > > + no_rt) rt_target=linear;;
> > > > + no_log) log_target=linear;;
> > > > + *) echo "${arg}: Unknown _dmerror_setup arg.";;
> > > > + esac
> > > > + done
> > > >
> > > > + # Scratch device
> > > > export DMERROR_DEV='/dev/mapper/error-test'
> > > > + _dmerror_setup_vars $SCRATCH_DEV
> > > >
> > > > - export DMLINEAR_TABLE="0 $blk_dev_size linear $dm_backing_dev 0"
> > > > + # Realtime device. We reassign SCRATCH_RTDEV so that all the scratch
> > > > + # helpers continue to work unmodified.
> > > > + if [ -n "$SCRATCH_RTDEV" ]; then
> > > > + if [ -z "$NON_ERROR_RTDEV" ]; then
> > > > + # Set up the device switch
> > > > + local dm_backing_dev=$SCRATCH_RTDEV
> > > > + export NON_ERROR_RTDEV="$SCRATCH_RTDEV"
> > > > + SCRATCH_RTDEV='/dev/mapper/error-rttest'
> > > > + else
> > > > + # Already set up; recreate tables
> > > > + local dm_backing_dev="$NON_ERROR_RTDEV"
> > > > + fi
> > > >
> > > > - export DMERROR_TABLE="0 $blk_dev_size error $dm_backing_dev 0"
> > > > + _dmerror_setup_vars $dm_backing_dev RT $rt_target
> > > > + fi
> > > > +
> > > > + # External log device. We reassign SCRATCH_LOGDEV so that all the
> > > > + # scratch helpers continue to work unmodified.
> > > > + if [ -n "$SCRATCH_LOGDEV" ]; then
> > > > + if [ -z "$NON_ERROR_LOGDEV" ]; then
> > > > + # Set up the device switch
> > > > + local dm_backing_dev=$SCRATCH_LOGDEV
> > > > + export NON_ERROR_LOGDEV="$SCRATCH_LOGDEV"
> > > > + SCRATCH_LOGDEV='/dev/mapper/error-logtest'
> > > > + else
> > > > + # Already set up; recreate tables
> > > > + local dm_backing_dev="$NON_ERROR_LOGDEV"
> > > > + fi
> > > > +
> > > > + _dmerror_setup_vars $dm_backing_dev LOG $log_target
> > > > + fi
> > > > }
> > > >
> > > > _dmerror_init()
> > > > {
> > > > - _dmerror_setup
> > > > + _dmerror_setup "[email protected]"
> > > > +
> > > > _dmsetup_remove error-test
> > > > _dmsetup_create error-test --table "$DMLINEAR_TABLE" || \
> > > > _fatal "failed to create dm linear device"
> > > > +
> > > > + if [ -n "$NON_ERROR_RTDEV" ]; then
> > > > + _dmsetup_remove error-rttest
> > > > + _dmsetup_create error-rttest --table "$DMLINEAR_RTTABLE" || \
> > > > + _fatal "failed to create dm linear rt device"
> > > > + fi
> > > > +
> > > > + if [ -n "$NON_ERROR_LOGDEV" ]; then
> > > > + _dmsetup_remove error-logtest
> > > > + _dmsetup_create error-logtest --table "$DMLINEAR_LOGTABLE" || \
> > > > + _fatal "failed to create dm linear log device"
> > > > + fi
> > > > }
> > > >
> > > > _dmerror_mount()
> > > > @@ -39,11 +102,27 @@ _dmerror_unmount()
> > > >
> > > > _dmerror_cleanup()
> > > > {
> > > > + test -n "$NON_ERROR_LOGDEV" && $DMSETUP_PROG resume error-logtest &>/dev/null
> > > > + test -n "$NON_ERROR_RTDEV" && $DMSETUP_PROG resume error-rttest &>/dev/null
> > > > $DMSETUP_PROG resume error-test > /dev/null 2>&1
> > > > +
> > > > $UMOUNT_PROG $SCRATCH_MNT > /dev/null 2>&1
> > > > +
> > > > + test -n "$NON_ERROR_LOGDEV" && _dmsetup_remove error-logtest
> > > > + test -n "$NON_ERROR_RTDEV" && _dmsetup_remove error-rttest
> > > > _dmsetup_remove error-test
> > > >
> > > > unset DMERROR_DEV DMLINEAR_TABLE DMERROR_TABLE
> > > > +
> > > > + if [ -n "$NON_ERROR_LOGDEV" ]; then
> > > > + SCRATCH_LOGDEV="$NON_ERROR_LOGDEV"
> > > > + unset NON_ERROR_LOGDEV DMLINEAR_LOGTABLE DMERROR_LOGTABLE
> > > > + fi
> > > > +
> > > > + if [ -n "$NON_ERROR_RTDEV" ]; then
> > > > + SCRATCH_RTDEV="$NON_ERROR_RTDEV"
> > > > + unset NON_ERROR_RTDEV DMLINEAR_RTTABLE DMERROR_RTTABLE
> > > > + fi
> > > > }
> > > >
> > > > _dmerror_load_error_table()
> > > > @@ -59,12 +138,47 @@ _dmerror_load_error_table()
> > > > suspend_opt="$*"
> > > > fi
> > > >
> > > > + # Suspend the scratch device before the log and realtime devices so
> > > > + # that the kernel can freeze and flush the filesystem if the caller
> > > > + # wanted a freeze.
> > > > $DMSETUP_PROG suspend $suspend_opt error-test
> > > > [ $? -ne 0 ] && _fail "dmsetup suspend failed"
> > > >
> > > > + if [ -n "$NON_ERROR_RTDEV" ]; then
> > > > + $DMSETUP_PROG suspend $suspend_opt error-rttest
> > > > + [ $? -ne 0 ] && _fail "failed to suspend error-rttest"
> > > > + fi
> > > > +
> > > > + if [ -n "$NON_ERROR_LOGDEV" ]; then
> > > > + $DMSETUP_PROG suspend $suspend_opt error-logtest
> > > > + [ $? -ne 0 ] && _fail "failed to suspend error-logtest"
> > > > + fi
> > > > +
> > > > + # Load new table
> > > > $DMSETUP_PROG load error-test --table "$DMERROR_TABLE"
> > > > load_res=$?
> > > >
> > > > + if [ -n "$NON_ERROR_RTDEV" ]; then
> > > > + $DMSETUP_PROG load error-rttest --table "$DMERROR_RTTABLE"
> > > > + [ $? -ne 0 ] && _fail "failed to load error table into error-rttest"
> > > > + fi
> > > > +
> > > > + if [ -n "$NON_ERROR_LOGDEV" ]; then
> > > > + $DMSETUP_PROG load error-logtest --table "$DMERROR_LOGTABLE"
> > > > + [ $? -ne 0 ] && _fail "failed to load error table into error-logtest"
> > > > + fi
> > > > +
> > > > + # Resume devices in the opposite order that we suspended them.
> > > > + if [ -n "$NON_ERROR_LOGDEV" ]; then
> > > > + $DMSETUP_PROG resume error-logtest
> > > > + [ $? -ne 0 ] && _fail "failed to resume error-logtest"
> > > > + fi
> > > > +
> > > > + if [ -n "$NON_ERROR_RTDEV" ]; then
> > > > + $DMSETUP_PROG resume error-rttest
> > > > + [ $? -ne 0 ] && _fail "failed to resume error-rttest"
> > > > + fi
> > > > +
> > > > $DMSETUP_PROG resume error-test
> > > > resume_res=$?
> > > >
> > > > @@ -85,12 +199,47 @@ _dmerror_load_working_table()
> > > > suspend_opt="$*"
> > > > fi
> > > >
> > > > + # Suspend the scratch device before the log and realtime devices so
> > > > + # that the kernel can freeze and flush the filesystem if the caller
> > > > + # wanted a freeze.
> > > > $DMSETUP_PROG suspend $suspend_opt error-test
> > > > [ $? -ne 0 ] && _fail "dmsetup suspend failed"
> > > >
> > > > + if [ -n "$NON_ERROR_RTDEV" ]; then
> > > > + $DMSETUP_PROG suspend $suspend_opt error-rttest
> > > > + [ $? -ne 0 ] && _fail "failed to suspend error-rttest"
> > > > + fi
> > > > +
> > > > + if [ -n "$NON_ERROR_LOGDEV" ]; then
> > > > + $DMSETUP_PROG suspend $suspend_opt error-logtest
> > > > + [ $? -ne 0 ] && _fail "failed to suspend error-logtest"
> > > > + fi
> > > > +
> > > > + # Load new table
> > > > $DMSETUP_PROG load error-test --table "$DMLINEAR_TABLE"
> > > > load_res=$?
> > > >
> > > > + if [ -n "$NON_ERROR_RTDEV" ]; then
> > > > + $DMSETUP_PROG load error-rttest --table "$DMLINEAR_RTTABLE"
> > > > + [ $? -ne 0 ] && _fail "failed to load working table into error-rttest"
> > > > + fi
> > > > +
> > > > + if [ -n "$NON_ERROR_LOGDEV" ]; then
> > > > + $DMSETUP_PROG load error-logtest --table "$DMLINEAR_LOGTABLE"
> > > > + [ $? -ne 0 ] && _fail "failed to load working table into error-logtest"
> > > > + fi
> > > > +
> > > > + # Resume devices in the opposite order that we suspended them.
> > > > + if [ -n "$NON_ERROR_LOGDEV" ]; then
> > > > + $DMSETUP_PROG resume error-logtest
> > > > + [ $? -ne 0 ] && _fail "failed to resume error-logtest"
> > > > + fi
> > > > +
> > > > + if [ -n "$NON_ERROR_RTDEV" ]; then
> > > > + $DMSETUP_PROG resume error-rttest
> > > > + [ $? -ne 0 ] && _fail "failed to resume error-rttest"
> > > > + fi
> > > > +
> > > > $DMSETUP_PROG resume error-test
> > > > resume_res=$?
> > > >
> > > > diff --git a/tests/generic/441 b/tests/generic/441
> > > > index 0ec751da..85f29a3a 100755
> > > > --- a/tests/generic/441
> > > > +++ b/tests/generic/441
> > > > @@ -52,7 +52,7 @@ unset SCRATCH_RTDEV
> > > >
> > > > echo "Format and mount"
> > > > _scratch_mkfs > $seqres.full 2>&1
> > > > -_dmerror_init
> > > > +_dmerror_init no_log
> > > > _dmerror_mount
> > > >
> > > > _require_fs_space $SCRATCH_MNT 65536
> > > > diff --git a/tests/generic/487 b/tests/generic/487
> > > > index fda8828d..3c9b2233 100755
> > > > --- a/tests/generic/487
> > > > +++ b/tests/generic/487
> > > > @@ -45,7 +45,7 @@ unset SCRATCH_RTDEV
> > > >
> > > > echo "Format and mount"
> > > > _scratch_mkfs > $seqres.full 2>&1
> > > > -_dmerror_init
> > > > +_dmerror_init no_log
> > > > _dmerror_mount
> > > >
> > > > datalen=65536
> > > >
> > >
> >



2022-08-01 21:17:14

by Darrick J. Wong

[permalink] [raw]
Subject: Re: [PATCH 2/2] dmerror: support external log and realtime devices

On Mon, Aug 01, 2022 at 10:46:20PM +0800, Zorro Lang wrote:
> On Mon, Aug 01, 2022 at 02:10:12AM +0800, Zorro Lang wrote:
> > On Sun, Jul 31, 2022 at 09:48:19AM -0700, Darrick J. Wong wrote:
> > > On Sat, Jul 30, 2022 at 06:18:34PM +0800, Zorro Lang wrote:
> > > > On Tue, Jul 26, 2022 at 12:48:42PM -0700, Darrick J. Wong wrote:
> > > > > From: Darrick J. Wong <[email protected]>
> > > > >
> > > > > Upgrade the dmerror code to coordinate making external scratch log and
> > > > > scratch realtime devices error out along with the scratch device. Note
> > > > > that unlike SCRATCH_DEV, we save the old rt/log devices in a separate
> > > > > variable and overwrite SCRATCH_{RT,LOG}DEV so that all the helper
> > > > > functions continue to work properly.
> > > > >
> > > > > This is very similar to what we did for dm-flakey a while back.
> > > > >
> > > > > Signed-off-by: Darrick J. Wong <[email protected]>
> > > > > ---
> > > >
> > > > Hi Darrick,
> > > >
> > > > I'll merge the patch 1/2 this week, but this 2/2 looks like bring in new
> > > > failures on ext4 with local.config as [0], for example[1], which is passed[2]
> > > > without this patch. It's fine on Btrfs and xfs for me.
> > > >
> > > > Thanks,
> > > > Zorro
> > > >
> > > > [0]
> > > > export TEST_DEV=/dev/sda5
> > > > export TEST_DIR=/mnt/test
> > > > export SCRATCH_DEV=/dev/sda3
> > > > export SCRATCH_MNT=/mnt/scratch
> > > > export USE_EXTERNAL=yes
> > > > export SCRATCH_LOGDEV=/dev/loop0
> > > >
> > > > [1]
> > > > generic/338 4s ... - output mismatch (see /root/git/xfstests/results//logdev/generic/338.out.bad)
> > > > --- tests/generic/338.out 2022-04-29 23:07:23.330499055 +0800
> > > > +++ /root/git/xfstests/results//logdev/generic/338.out.bad 2022-07-30 18:01:41.900765965 +0800
> > > > @@ -1,2 +1,4 @@
> > > > QA output created by 338
> > > > Silence is golden
> > > > +mount: /mnt/scratch: wrong fs type, bad option, bad superblock on /dev/mapper/error-test, missing codepage or helper program, or other error.
> > > > + dmesg(1) may have more information after failed mount system call.
> > >
> > > Hmm, any chance you could post the dmesg that goes with this?
> >
> > Sure, [1] is the dmesg with this patch. [2] is the dmesg without this patch.
>
> Hi Darrick,
>
> I think I know why it fails, but I don't know how to deal with it offically :)
> So cc [email protected] list.
>
> By testing, it fails after /dev/mapper/error-logtest be created. If we keep
> SCRATCH_LOGDEV no change, everything is fine for ext4. Or you need to use
> "-o journal_path=..." or "-o journal_dev=..." to specify the new journal device
> path. Or you have to re-make ext4 with "-J device=/dev/mapper/error-logtest".
>
> See below example:
>
> 1) ext4 extranal log device works:
> # mke2fs -O journal_dev /dev/loop0
> # mkfs.ext4 -F /dev/sda3 -J device=/dev/loop0
> # mount /dev/sda3 /mnt/scratch/
> # umount /mnt/scratch
>
> 2) Still works if only create error-test, don't touch LOGDEV:
> # dmsetup create error-test --table "0 104849408 linear /dev/sda3 0"
> # mount /dev/mapper/error-test /mnt/scratch/
> # umount /mnt/scratch
>
> 3) Fails if you create error-logtest ...:
> # dmsetup create error-logtest --table "0 2097152 linear /dev/loop0 0"
> # mount /dev/mapper/error-test /mnt/scratch/
> mount: /mnt/scratch: wrong fs type, bad option, bad superblock on /dev/mapper/error-test, missing codepage or helper program, or other error.
> dmesg(1) may have more information after failed mount system call.
>
> 4) ... Except you specify the new logdev path by mount option:
> # ls /dev/mapper/error-logtest -l
> lrwxrwxrwx. 1 root root 7 Aug 1 22:28 /dev/mapper/error-logtest -> ../dm-7
> # mount /dev/mapper/error-test /mnt/scratch/ -o journal_path=/dev/dm-7
> # umount /mnt/scratch
>
> 5) And after step 4, I can mount /dev/mapper/error-test again ...
> # mount /dev/mapper/error-test /mnt/scratch
> # umount /mnt/scratch
>
> I'm not an expert of ext4, that's only my test result, hope to get a clear
> explanation for that :)

Ahaaaaa... so it turns out that I've never tried running fstests with an
external log before, at least not with my current dev/test setup.

The first thing I noticed is that for ext[34], _scratch_options doesn't
inject a pointer to the external jbd2 device into the mount options like
it does for XFS. Normally this isn't a huge deal because mke2fs pairs
an ext* filesystem with a jbd2 device by writing its major/minor number
into the primary superblock:

# mke2fs -F -O journal_dev /dev/sdb ; mke2fs -T ext4 -F -J device=/dev/sdb /dev/sda; dumpe2fs -h /dev/sda | grep -i journal
mke2fs 1.46.6~WIP-2022-01-03 (3-Jan-2021)
/dev/sdb contains a jbd file system
Discarding device blocks: done
Creating filesystem with 2579968 4k blocks and 0 inodes
Filesystem UUID: 488a7034-f0cf-410a-b84c-fc80a50a0ffa
Superblock backups stored on blocks:

Zeroing journal device:
mke2fs 1.46.6~WIP-2022-01-03 (3-Jan-2021)
Using journal device's blocksize: 4096
/dev/sda contains a ext4 file system
created on Mon Aug 1 13:59:00 2022
Discarding device blocks: done
Creating filesystem with 2579968 4k blocks and 645904 inodes
Filesystem UUID: 72e4a31f-ac11-461c-b98a-35a2ec67729f
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632

Allocating group tables: done
Writing inode tables: done
Adding journal to device /dev/sdb: done
Writing superblocks and filesystem accounting information: done

dumpe2fs 1.46.6~WIP-2022-01-03 (3-Jan-2021)
Filesystem features: has_journal ext_attr resize_inode dir_index filetype extent 64bit flex_bg sparse_super large_file huge_file dir_nlink extra_isize metadata_csum
Journal UUID: 488a7034-f0cf-410a-b84c-fc80a50a0ffa
Journal device: 0x0810

(Note that major 8 minor 16 is /dev/sdb).

So even if the mount options don't explicitly point at a journal device,
ext4 can still try to open (8, 16) and see if it has the proper
superblock and a uuid that matches the filesystem.

The problem here is that if we change the external journal device by
creating a dm stack, the mount will fail because sdb is now opened
O_EXCL by device mapper, and the fs really should have been mounted with
"-o journal_path=/dev/dm-X". That's why mount works for you if you
specify the paths manually.

So I fixed all of that by creating a _scratch_ext4_options that injects
SCRATCH_LOGDEV into the mkfs and mount options if that variable is
defined and USE_EXTERNAL=yes. This makes it so that the SCRATCH_LOGDEV
overrides added by this common/dmerror change actually take effect for
mounting and formatting ext4 filesystems with external journals.

Of course I also discovered the interesting wart that the new fs mount
option parsing code *requires* that the last component of a path
argument point to a block device, because fs_lookup_param doesn't pass
LOOKUP_FOLLOW to filename_lookup(). Evidently that was a regression
introduced at some point between 5.0 and 5.19.

Sooooo... I've fixed fstests to handle this case and will send patches
in a few days.

--D

> Thanks,
> Zorro
>
> >
> > Thanks,
> > Zorro
> >
> > [1]
> > # ./check -s logdev generic/338
> > SECTION -- logdev
> > FSTYP -- ext4
> > PLATFORM -- Linux/x86_64 hp-dl380pg8-01 5.19.0-0.rc2.21.fc37.x86_64+debug #1 SMP PREEMPT_DYNAMIC Mon Jun 13 14:55:18 UTC 2022
> > MKFS_OPTIONS -- /dev/sda3
> > MOUNT_OPTIONS -- -o acl,user_xattr -o context=system_u:object_r:root_t:s0 /dev/sda3 /mnt/scratch
> >
> > generic/338 5s ... - output mismatch (see /root/git/xfstests/results//logdev/generic/338.out.bad)
> > --- tests/generic/338.out 2022-04-29 23:07:23.330499055 +0800
> > +++ /root/git/xfstests/results//logdev/generic/338.out.bad 2022-08-01 02:00:17.284965956 +0800
> > @@ -1,2 +1,4 @@
> > QA output created by 338
> > Silence is golden
> > +mount: /mnt/scratch: wrong fs type, bad option, bad superblock on /dev/mapper/error-test, missing codepage or helper program, or other error.
> > + dmesg(1) may have more information after failed mount system call.
> > ...
> > (Run 'diff -u /root/git/xfstests/tests/generic/338.out /root/git/xfstests/results//logdev/generic/338.out.bad' to see the entire diff)
> > Ran: generic/338
> > Failures: generic/338
> > Failed 1 of 1 tests
> >
> > # dmesg
> > [1382503.819432] run fstests generic/338 at 2022-08-01 02:00:13
> > [1382504.957989] EXT4-fs (dm-6): failed to open journal device unknown-block(7,0) -16
> > [1382504.987712] Buffer I/O error on dev dm-7, logical block 262128, async page read
> > [1382505.009371] Buffer I/O error on dev dm-6, logical block 13106160, async page read
> > [1382506.576023] 338 (277855): drop_caches: 3
> > [1382507.440513] EXT4-fs (sda5): unmounting filesystem.
> >
> > [2]
> > # ./check -s logdev generic/338
> > SECTION -- logdev
> > FSTYP -- ext4
> > PLATFORM -- Linux/x86_64 hp-dl380pg8-01 5.19.0-0.rc2.21.fc37.x86_64+debug #1 SMP PREEMPT_DYNAMIC Mon Jun 13 14:55:18 UTC 2022
> > MKFS_OPTIONS -- /dev/sda3
> > MOUNT_OPTIONS -- -o acl,user_xattr -o context=system_u:object_r:root_t:s0 /dev/sda3 /mnt/scratch
> >
> > generic/338 5s ... 3s
> > Ran: generic/338
> > Passed all 1 tests
> >
> > # dmesg
> > [1382877.411459] run fstests generic/338 at 2022-08-01 02:06:27
> > [1382878.778539] EXT4-fs (dm-6): mounted filesystem with ordered data mode. Quota mode: none.
> > [1382878.803639] Buffer I/O error on dev dm-6, logical block 13106160, async page read
> > [1382878.951444] 338 (279660): drop_caches: 3
> > [1382879.421933] EXT4-fs warning (device dm-6): htree_dirblock_to_tree:1044: inode #2: lblock 0: comm ls: error -5 reading directory block
> > [1382879.422007] EXT4-fs error (device dm-6): ext4_get_inode_loc:4587: inode #2: block 1064: comm ls: unable to read itable block
> > [1382879.422026] EXT4-fs error (device dm-6) in ext4_reserve_inode_write:5756: IO failure
> > [1382879.422031] EXT4-fs error (device dm-6): ext4_dirty_inode:5952: inode #2: comm ls: mark_inode_dirty error
> > [1382879.750038] EXT4-fs error (device dm-6): __ext4_find_entry:1635: inode #2: comm xfs_io: reading directory lblock 0
> > [1382880.180381] Buffer I/O error on dev dm-6, logical block 0, lost async page write
> > [1382880.180961] EXT4-fs (dm-6): unmounting filesystem.
> > [1382880.181541] Aborting journal on device loop0.
> > [1382880.182777] EXT4-fs error (device dm-6): ext4_put_super:1229: comm umount: Couldn't clean up the journal
> > [1382880.182798] EXT4-fs (dm-6): previous I/O error to superblock detected
> > [1382880.182817] Buffer I/O error on dev dm-6, logical block 0, lost sync page write
> > [1382880.182860] EXT4-fs (dm-6): I/O error while writing superblock
> > [1382880.182867] EXT4-fs (dm-6): Remounting filesystem read-only
> > [1382880.742572] EXT4-fs (sda5): unmounting filesystem.
> >
> > >
> > > --D
> > >
> > > > ...
> > > > (Run 'diff -u /root/git/xfstests/tests/generic/338.out /root/git/xfstests/results//logdev/generic/338.out.bad' to see the entire diff)
> > > > generic/441 5s ... - output mismatch (see /root/git/xfstests/results//logdev/generic/441.out.bad)
> > > > --- tests/generic/441.out 2022-04-29 23:07:23.406499916 +0800
> > > > +++ /root/git/xfstests/results//logdev/generic/441.out.bad 2022-07-30 18:01:46.829822438 +0800
> > > > @@ -1,3 +1,6 @@
> > > > QA output created by 441
> > > > Format and mount
> > > > -Test passed!
> > > > +mount: /mnt/scratch: wrong fs type, bad option, bad superblock on /dev/mapper/error-test, missing codepage or helper program, or other error.
> > > > + dmesg(1) may have more information after failed mount system call.
> > > > +Success on second fsync on fd[0]!
> > > > +umount: /mnt/scratch: not mounted.
> > > > ...
> > > > (Run 'diff -u /root/git/xfstests/tests/generic/441.out /root/git/xfstests/results//logdev/generic/441.out.bad' to see the entire diff)
> > > >
> > > > [2]
> > > > generic/338 4s ... 5s
> > > > generic/441 5s ... 5s
> > > > generic/442 3s ... 3s
> > > >
> > > >
> > > > > common/dmerror | 159 +++++++++++++++++++++++++++++++++++++++++++++++++++--
> > > > > tests/generic/441 | 2 -
> > > > > tests/generic/487 | 2 -
> > > > > 3 files changed, 156 insertions(+), 7 deletions(-)
> > > > >
> > > > >
> > > > > diff --git a/common/dmerror b/common/dmerror
> > > > > index 01a4c8b5..85ef9a16 100644
> > > > > --- a/common/dmerror
> > > > > +++ b/common/dmerror
> > > > > @@ -4,25 +4,88 @@
> > > > > #
> > > > > # common functions for setting up and tearing down a dmerror device
> > > > >
> > > > > +_dmerror_setup_vars()
> > > > > +{
> > > > > + local backing_dev="$1"
> > > > > + local tag="$2"
> > > > > + local target="$3"
> > > > > +
> > > > > + test -z "$target" && target=error
> > > > > + local blk_dev_size=$(blockdev --getsz "$backing_dev")
> > > > > +
> > > > > + eval export "DMLINEAR_${tag}TABLE=\"0 $blk_dev_size linear $backing_dev 0\""
> > > > > + eval export "DMERROR_${tag}TABLE=\"0 $blk_dev_size $target $backing_dev 0\""
> > > > > +}
> > > > > +
> > > > > _dmerror_setup()
> > > > > {
> > > > > - local dm_backing_dev=$SCRATCH_DEV
> > > > > + local rt_target=
> > > > > + local linear_target=
> > > > >
> > > > > - local blk_dev_size=`blockdev --getsz $dm_backing_dev`
> > > > > + for arg in "[email protected]"; do
> > > > > + case "${arg}" in
> > > > > + no_rt) rt_target=linear;;
> > > > > + no_log) log_target=linear;;
> > > > > + *) echo "${arg}: Unknown _dmerror_setup arg.";;
> > > > > + esac
> > > > > + done
> > > > >
> > > > > + # Scratch device
> > > > > export DMERROR_DEV='/dev/mapper/error-test'
> > > > > + _dmerror_setup_vars $SCRATCH_DEV
> > > > >
> > > > > - export DMLINEAR_TABLE="0 $blk_dev_size linear $dm_backing_dev 0"
> > > > > + # Realtime device. We reassign SCRATCH_RTDEV so that all the scratch
> > > > > + # helpers continue to work unmodified.
> > > > > + if [ -n "$SCRATCH_RTDEV" ]; then
> > > > > + if [ -z "$NON_ERROR_RTDEV" ]; then
> > > > > + # Set up the device switch
> > > > > + local dm_backing_dev=$SCRATCH_RTDEV
> > > > > + export NON_ERROR_RTDEV="$SCRATCH_RTDEV"
> > > > > + SCRATCH_RTDEV='/dev/mapper/error-rttest'
> > > > > + else
> > > > > + # Already set up; recreate tables
> > > > > + local dm_backing_dev="$NON_ERROR_RTDEV"
> > > > > + fi
> > > > >
> > > > > - export DMERROR_TABLE="0 $blk_dev_size error $dm_backing_dev 0"
> > > > > + _dmerror_setup_vars $dm_backing_dev RT $rt_target
> > > > > + fi
> > > > > +
> > > > > + # External log device. We reassign SCRATCH_LOGDEV so that all the
> > > > > + # scratch helpers continue to work unmodified.
> > > > > + if [ -n "$SCRATCH_LOGDEV" ]; then
> > > > > + if [ -z "$NON_ERROR_LOGDEV" ]; then
> > > > > + # Set up the device switch
> > > > > + local dm_backing_dev=$SCRATCH_LOGDEV
> > > > > + export NON_ERROR_LOGDEV="$SCRATCH_LOGDEV"
> > > > > + SCRATCH_LOGDEV='/dev/mapper/error-logtest'
> > > > > + else
> > > > > + # Already set up; recreate tables
> > > > > + local dm_backing_dev="$NON_ERROR_LOGDEV"
> > > > > + fi
> > > > > +
> > > > > + _dmerror_setup_vars $dm_backing_dev LOG $log_target
> > > > > + fi
> > > > > }
> > > > >
> > > > > _dmerror_init()
> > > > > {
> > > > > - _dmerror_setup
> > > > > + _dmerror_setup "[email protected]"
> > > > > +
> > > > > _dmsetup_remove error-test
> > > > > _dmsetup_create error-test --table "$DMLINEAR_TABLE" || \
> > > > > _fatal "failed to create dm linear device"
> > > > > +
> > > > > + if [ -n "$NON_ERROR_RTDEV" ]; then
> > > > > + _dmsetup_remove error-rttest
> > > > > + _dmsetup_create error-rttest --table "$DMLINEAR_RTTABLE" || \
> > > > > + _fatal "failed to create dm linear rt device"
> > > > > + fi
> > > > > +
> > > > > + if [ -n "$NON_ERROR_LOGDEV" ]; then
> > > > > + _dmsetup_remove error-logtest
> > > > > + _dmsetup_create error-logtest --table "$DMLINEAR_LOGTABLE" || \
> > > > > + _fatal "failed to create dm linear log device"
> > > > > + fi
> > > > > }
> > > > >
> > > > > _dmerror_mount()
> > > > > @@ -39,11 +102,27 @@ _dmerror_unmount()
> > > > >
> > > > > _dmerror_cleanup()
> > > > > {
> > > > > + test -n "$NON_ERROR_LOGDEV" && $DMSETUP_PROG resume error-logtest &>/dev/null
> > > > > + test -n "$NON_ERROR_RTDEV" && $DMSETUP_PROG resume error-rttest &>/dev/null
> > > > > $DMSETUP_PROG resume error-test > /dev/null 2>&1
> > > > > +
> > > > > $UMOUNT_PROG $SCRATCH_MNT > /dev/null 2>&1
> > > > > +
> > > > > + test -n "$NON_ERROR_LOGDEV" && _dmsetup_remove error-logtest
> > > > > + test -n "$NON_ERROR_RTDEV" && _dmsetup_remove error-rttest
> > > > > _dmsetup_remove error-test
> > > > >
> > > > > unset DMERROR_DEV DMLINEAR_TABLE DMERROR_TABLE
> > > > > +
> > > > > + if [ -n "$NON_ERROR_LOGDEV" ]; then
> > > > > + SCRATCH_LOGDEV="$NON_ERROR_LOGDEV"
> > > > > + unset NON_ERROR_LOGDEV DMLINEAR_LOGTABLE DMERROR_LOGTABLE
> > > > > + fi
> > > > > +
> > > > > + if [ -n "$NON_ERROR_RTDEV" ]; then
> > > > > + SCRATCH_RTDEV="$NON_ERROR_RTDEV"
> > > > > + unset NON_ERROR_RTDEV DMLINEAR_RTTABLE DMERROR_RTTABLE
> > > > > + fi
> > > > > }
> > > > >
> > > > > _dmerror_load_error_table()
> > > > > @@ -59,12 +138,47 @@ _dmerror_load_error_table()
> > > > > suspend_opt="$*"
> > > > > fi
> > > > >
> > > > > + # Suspend the scratch device before the log and realtime devices so
> > > > > + # that the kernel can freeze and flush the filesystem if the caller
> > > > > + # wanted a freeze.
> > > > > $DMSETUP_PROG suspend $suspend_opt error-test
> > > > > [ $? -ne 0 ] && _fail "dmsetup suspend failed"
> > > > >
> > > > > + if [ -n "$NON_ERROR_RTDEV" ]; then
> > > > > + $DMSETUP_PROG suspend $suspend_opt error-rttest
> > > > > + [ $? -ne 0 ] && _fail "failed to suspend error-rttest"
> > > > > + fi
> > > > > +
> > > > > + if [ -n "$NON_ERROR_LOGDEV" ]; then
> > > > > + $DMSETUP_PROG suspend $suspend_opt error-logtest
> > > > > + [ $? -ne 0 ] && _fail "failed to suspend error-logtest"
> > > > > + fi
> > > > > +
> > > > > + # Load new table
> > > > > $DMSETUP_PROG load error-test --table "$DMERROR_TABLE"
> > > > > load_res=$?
> > > > >
> > > > > + if [ -n "$NON_ERROR_RTDEV" ]; then
> > > > > + $DMSETUP_PROG load error-rttest --table "$DMERROR_RTTABLE"
> > > > > + [ $? -ne 0 ] && _fail "failed to load error table into error-rttest"
> > > > > + fi
> > > > > +
> > > > > + if [ -n "$NON_ERROR_LOGDEV" ]; then
> > > > > + $DMSETUP_PROG load error-logtest --table "$DMERROR_LOGTABLE"
> > > > > + [ $? -ne 0 ] && _fail "failed to load error table into error-logtest"
> > > > > + fi
> > > > > +
> > > > > + # Resume devices in the opposite order that we suspended them.
> > > > > + if [ -n "$NON_ERROR_LOGDEV" ]; then
> > > > > + $DMSETUP_PROG resume error-logtest
> > > > > + [ $? -ne 0 ] && _fail "failed to resume error-logtest"
> > > > > + fi
> > > > > +
> > > > > + if [ -n "$NON_ERROR_RTDEV" ]; then
> > > > > + $DMSETUP_PROG resume error-rttest
> > > > > + [ $? -ne 0 ] && _fail "failed to resume error-rttest"
> > > > > + fi
> > > > > +
> > > > > $DMSETUP_PROG resume error-test
> > > > > resume_res=$?
> > > > >
> > > > > @@ -85,12 +199,47 @@ _dmerror_load_working_table()
> > > > > suspend_opt="$*"
> > > > > fi
> > > > >
> > > > > + # Suspend the scratch device before the log and realtime devices so
> > > > > + # that the kernel can freeze and flush the filesystem if the caller
> > > > > + # wanted a freeze.
> > > > > $DMSETUP_PROG suspend $suspend_opt error-test
> > > > > [ $? -ne 0 ] && _fail "dmsetup suspend failed"
> > > > >
> > > > > + if [ -n "$NON_ERROR_RTDEV" ]; then
> > > > > + $DMSETUP_PROG suspend $suspend_opt error-rttest
> > > > > + [ $? -ne 0 ] && _fail "failed to suspend error-rttest"
> > > > > + fi
> > > > > +
> > > > > + if [ -n "$NON_ERROR_LOGDEV" ]; then
> > > > > + $DMSETUP_PROG suspend $suspend_opt error-logtest
> > > > > + [ $? -ne 0 ] && _fail "failed to suspend error-logtest"
> > > > > + fi
> > > > > +
> > > > > + # Load new table
> > > > > $DMSETUP_PROG load error-test --table "$DMLINEAR_TABLE"
> > > > > load_res=$?
> > > > >
> > > > > + if [ -n "$NON_ERROR_RTDEV" ]; then
> > > > > + $DMSETUP_PROG load error-rttest --table "$DMLINEAR_RTTABLE"
> > > > > + [ $? -ne 0 ] && _fail "failed to load working table into error-rttest"
> > > > > + fi
> > > > > +
> > > > > + if [ -n "$NON_ERROR_LOGDEV" ]; then
> > > > > + $DMSETUP_PROG load error-logtest --table "$DMLINEAR_LOGTABLE"
> > > > > + [ $? -ne 0 ] && _fail "failed to load working table into error-logtest"
> > > > > + fi
> > > > > +
> > > > > + # Resume devices in the opposite order that we suspended them.
> > > > > + if [ -n "$NON_ERROR_LOGDEV" ]; then
> > > > > + $DMSETUP_PROG resume error-logtest
> > > > > + [ $? -ne 0 ] && _fail "failed to resume error-logtest"
> > > > > + fi
> > > > > +
> > > > > + if [ -n "$NON_ERROR_RTDEV" ]; then
> > > > > + $DMSETUP_PROG resume error-rttest
> > > > > + [ $? -ne 0 ] && _fail "failed to resume error-rttest"
> > > > > + fi
> > > > > +
> > > > > $DMSETUP_PROG resume error-test
> > > > > resume_res=$?
> > > > >
> > > > > diff --git a/tests/generic/441 b/tests/generic/441
> > > > > index 0ec751da..85f29a3a 100755
> > > > > --- a/tests/generic/441
> > > > > +++ b/tests/generic/441
> > > > > @@ -52,7 +52,7 @@ unset SCRATCH_RTDEV
> > > > >
> > > > > echo "Format and mount"
> > > > > _scratch_mkfs > $seqres.full 2>&1
> > > > > -_dmerror_init
> > > > > +_dmerror_init no_log
> > > > > _dmerror_mount
> > > > >
> > > > > _require_fs_space $SCRATCH_MNT 65536
> > > > > diff --git a/tests/generic/487 b/tests/generic/487
> > > > > index fda8828d..3c9b2233 100755
> > > > > --- a/tests/generic/487
> > > > > +++ b/tests/generic/487
> > > > > @@ -45,7 +45,7 @@ unset SCRATCH_RTDEV
> > > > >
> > > > > echo "Format and mount"
> > > > > _scratch_mkfs > $seqres.full 2>&1
> > > > > -_dmerror_init
> > > > > +_dmerror_init no_log
> > > > > _dmerror_mount
> > > > >
> > > > > datalen=65536
> > > > >
> > > >
> > >
>