On Mon, Mar 22 2021 at 4:11am -0400,
Christoph Hellwig <hch@xxxxxxxxxxxxx> wrote:
> On Sat, Mar 20, 2021 at 03:19:23PM +0800, Zhiqiang Liu wrote:
> > From: Zhiqiang Liu <liuzhiqiang26@xxxxxxxxxx>
> >
> > When we make IO stress test on multipath device, there will
> > be a metadata err because of wrong path. In the test, we
> > concurrent execute 'iscsi device login|logout' and
> > 'multipath -r' command with IO stress on multipath device.
> > In some case, systemd-udevd may have not time to process
> > uevents of iscsi device logout|login, and then 'multipath -r'
> > command triggers multipathd daemon calls ioctl to load table
> > with incorrect old device info from systemd-udevd.
> > Then, one iscsi path may be incorrectly attached to another
> > multipath which has different uuid. Finally, the metadata err
> > occurs when umounting filesystem to down write metadata on
> > the iscsi device which is actually not owned by the multipath
> > device.
> >
> > So we need to check whether all pgpaths of one multipath have
> > the same uuid, if not, we should throw a error.
> >
> > Signed-off-by: Zhiqiang Liu <liuzhiqiang26@xxxxxxxxxx>
> > Signed-off-by: lixiaokeng <lixiaokeng@xxxxxxxxxx>
> > Signed-off-by: linfeilong <linfeilong@xxxxxxxxxx>
> > Signed-off-by: Wubo <wubo40@xxxxxxxxxx>
> > ---
> > drivers/md/dm-mpath.c | 52 +++++++++++++++++++++++++++++++++++++++++
> > drivers/scsi/scsi_lib.c | 1 +
> > 2 files changed, 53 insertions(+)
> >
> > diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
> > index bced42f082b0..f0b995784b53 100644
> > --- a/drivers/md/dm-mpath.c
> > +++ b/drivers/md/dm-mpath.c
> > @@ -24,6 +24,7 @@
> > #include <linux/workqueue.h>
> > #include <linux/delay.h>
> > #include <scsi/scsi_dh.h>
> > +#include <linux/dm-ioctl.h>
> > #include <linux/atomic.h>
> > #include <linux/blk-mq.h>
> >
> > @@ -1169,6 +1170,45 @@ static int parse_features(struct dm_arg_set *as, struct multipath *m)
> > return r;
> > }
> >
> > +#define SCSI_VPD_LUN_ID_PREFIX_LEN 4
> > +#define MPATH_UUID_PREFIX_LEN 7
> > +static int check_pg_uuid(struct priority_group *pg, char *md_uuid)
> > +{
> > + char pgpath_uuid[DM_UUID_LEN] = {0};
> > + struct request_queue *q;
> > + struct pgpath *pgpath;
> > + struct scsi_device *sdev;
> > + ssize_t count;
> > + int r = 0;
> > +
> > + list_for_each_entry(pgpath, &pg->pgpaths, list) {
> > + q = bdev_get_queue(pgpath->path.dev->bdev);
> > + sdev = scsi_device_from_queue(q);
>
> Common dm-multipath code should never poke into scsi internals. This
> is something for the device handler to check. It probably also won't
> work for all older devices.
Definitely.
But that aside, userspace (multipathd) _should_ be able to do extra
validation, _before_ pushing down a new table to the kernel, rather than
forcing the kernel to do it.
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