On 3/15/19 1:55 AM, Omar Sandoval wrote:
> On Thu, Mar 14, 2019 at 07:45:17PM +0800, Dongli Zhang wrote:
>> loop/001 does not test whether all partitions are removed successfully
>> during loop device partition scanning. As a result, the regression
>> introduced by 0da03cab87e6 ("loop: Fix deadlock when calling
>> blkdev_reread_part()") can not be detected.
>>
>> The regression will generate below message in dmesg:
>>
>> [ 464.414043] __loop_clr_fd: partition scan of loop0 failed (rc=-22)
>>
>> and leave orphan partitions like below:
>>
>> - /dev/loop0p1
>> - /sys/block/loop0/loop0p1
>>
>> This patch verifies all partitions are removed by checking if there is
>> /sys/block/loopX/loopXpY left. The expected number of partitions left is 0.
>
> Thanks for the test! A couple of comments below.
>
>> Signed-off-by: Dongli Zhang <dongli.zhang@xxxxxxxxxx>
>> ---
>> tests/loop/001 | 5 +++++
>> tests/loop/001.out | 1 +
>> 2 files changed, 6 insertions(+)
>>
>> diff --git a/tests/loop/001 b/tests/loop/001
>> index 47f760a..a0326b7 100755
>> --- a/tests/loop/001
>> +++ b/tests/loop/001
>> @@ -4,6 +4,9 @@
>> #
>> # Test loop device partition scanning. Regression test for commit e02898b42380
>> # ("loop: fix LO_FLAGS_PARTSCAN hang").
>> +#
>> +# Test loop device paritition scanning. Regression test for commit 758a58d0bc67
>> +# ("loop: set GENHD_FL_NO_PART_SCAN after blkdev_reread_part()").
>
> These can just be combined to
>
> # Test loop device partition scanning. Regression test for commits e02898b42380
> # ("loop: fix LO_FLAGS_PARTSCAN hang") and 758a58d0bc67 ("loop: set
> # GENHD_FL_NO_PART_SCAN after blkdev_reread_part()").
>
>> . tests/loop/rc
>>
>> @@ -24,9 +27,11 @@ test() {
>> mkpart primary 50% 100%
>>
>> loop_device="$(losetup -P -f --show "$TMPDIR/img")"
>> + loop_name=${loop_device:5}
>> lsblk -ln "$loop_device" | wc -l
>>
>> losetup -d "$loop_device"
>> + ls /sys/block/$loop_name | grep loop | wc -l
>
> We can just repeat the same `lsblk -ln "$loop_device" | wc -l` from
> earlier, right? That's a bit cleaner than the hardcoded string slicing
> and ls.
Seems 'lsblk' does not work here.
step1: truncate -s 100M /tmp/tmp.raw
step2: parted /tmp/tmp.raw --script mklabel msdos \
mkpart primary 0% 50% mkpart primary 50% 100%
step3: losetup -P -f --show /tmp/tmp.raw
Now we are able to see two loop partitions from 'lsblk'
# lsblk -ln /dev/loop0
loop0 7:0 0 100M 0 loop
loop0p1 259:0 0 50M 0 loop
loop0p2 259:1 0 50M 0 loop
step4: # losetup -d /dev/loop0
There is below syslog as partscan is failed.
[ 261.181049] __loop_clr_fd: partition scan of loop0 failed (rc=-22)
There are 2 partitions left:
# ls /dev | grep loop0
loop0
loop0p1
loop0p2
# ls /sys/block/loop0 | grep loop
loop0p1
loop0p2
However, 'lsblk -ln' does not report the orphan paritions:
# lsblk -ln
sr0 11:0 1 1024M 0 rom
sda 8:0 0 20G 0 disk
sda2 8:2 0 1K 0 part
sda5 8:5 0 4.1G 0 part [SWAP]
sda1 8:1 0 15.9G 0 part /
Therefore, we would not be able to use 'lsblk' here.
Dongli Zhang
