search

opensvc / multipath-tools

Other
59 stars 47 forks source link

multipathd show paths format "<wild cards>" fails silently when the path checker wildcard is used on orphaned entries #62

Closed datamattsson closed 1 year ago

datamattsson commented 1 year ago

In newer versions of multipath (v0.8.7 and above) the multipathd show paths format command fails silently when the path checker is asked for on orphaned entries:

# multipathd show paths format "%w %d %t %i %o %T %c %s %m"
uuid                              dev dm_st hcil    dev_st  chk_st checker vend/prod/rev multipath
2c6f914c06154a5c56c9ce90022851301 sdd undef 8:0:0:1 unknown undef  root@jammies-cpu2:~# echo $?
0

Replacing the %c with a %z:

# multipathd show paths format "%w %d %t %i %o %T %z %s %m"
uuid                              dev dm_st hcil    dev_st  chk_st serial                           vend/prod/rev multipath
2c6f914c06154a5c56c9ce90022851301 sdd undef 8:0:0:1 unknown undef  c6f914c06154a5c56c9ce90022851301 Nimble,Server [orphan]
2c6f914c06154a5c56c9ce90022851301 sdc undef 7:0:0:1 unknown undef  c6f914c06154a5c56c9ce90022851301 Nimble,Server [orphan]

The above example is using multipath-tools v0.8.8 (03/12, 2021) stock from Ubuntu 22.04.1 but I've reproduced this on

The devices it fails with are either iSCSI or FC.

SLES 15 SP3 uses multipath-tools v0.8.5 (11/09, 2020) and does not exhibit this problem and I've tested as low as multipath-tools v0.4.9 (05/33, 2016) on CentOS 7, which does not have this issue either.

This issue has caused a lot of angst mainly because the failed command return code is 0 as failures occurs in silence in our tools and libraries.

bmarzins commented 1 year ago

I'm pretty sure that issue was introduced with:

cd1756629762393da4ebb50a22b2badab8446369 multipathd: use strbuf in cli_handler functions

and it has been fixed upstream with:

95814552235e338f97fdf2b32413f928710a0ac4 libmultipath: fix 'show paths format' failure

I know this fix is in the Fedora Rawhide device-mapper-multipath build, but I'm not sure what other releases it may be in.

bmarzins commented 1 year ago

Well to be more precise, cd1756629762393da4ebb50a22b2badab8446369 was the commit that made multipathd stop returning failure when trying to show the checker of orphan paths. I don't think multipathd ever correctly showed an orphan path if the "%c" format wildcard was used, until 95814552235e338f97fdf2b32413f928710a0ac4

datamattsson commented 1 year ago

Thank you so much @bmarzins for the background information. I wonder why I couldn't find these.