Many thanks for investigating. Yes, this does appear to be fixed in
4.15.0-144-generic
--
Chris Ritson
Newcastle University IT Service - School of Computing.
Working mostly from home due to 25% occupancy target for Urban
Sciences Building: https://www.ncl.ac.uk/itservice/remoteworking/
From: boun...@canonical.com on behalf of Matthew
Ruffell <1930...@bugs.launchpad.net>
Sent: 03 June 2021 04:57
To: Chris Ritson
Subject: [Bug 1930603] Re: mount.cifs fails to mount DFS shares
⚠ External sender. Take care when opening links or attachments. Do not
provide your login details.
Hi Chris,
Thanks for reporting! Looking at the difference between
4.15.0-142-generic and 4.15.0-143-generic, there is one commit:
ubuntu-bionic$ git log --grep "cifs"
Ubuntu-4.15.0-142.146..Ubuntu-4.15.0-143.147
commit 7dd995facbb57b35b10715a27e252c8af5a39a6c
Author: Shyam Prasad N
Date: Thu Feb 11 03:26:54 2021 -0800
cifs: Set CIFS_MOUNT_USE_PREFIX_PATH flag on setting
cifs_sb->prepath.
BugLink:
https://eur03.safelinks.protection.outlook.com/?url=https%3A%2F%2Fbugs.launchpad.net%2Fbugs%2F1919380data=04%7C01%7CChris.Ritson%40newcastle.ac.uk%7Cf393674c32b74f499e3e08d92644d8d4%7C9c5012c9b61644c2a91766814fbe3e87%7C1%7C0%7C637582900140610302%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000sdata=3a75bQX1lX7Ez1ukWckbpGQff8sGH3qTWje%2FxCaY93E%3Dreserved=0
[ Upstream commit a738c93fb1c17e386a09304b517b1c6b2a6a5a8b ]
While debugging another issue today, Steve and I noticed that if a
subdir for a file share is already mounted on the client, any new
mount of any other subdir (or the file share root) of the same share
results in sharing the cifs superblock, which e.g. can result in
incorrect device name.
While setting prefix path for the root of a cifs_sb,
CIFS_MOUNT_USE_PREFIX_PATH flag should also be set.
Without it, prepath is not even considered in some places,
and output of "mount" and various /proc/<>/*mount* related
options can be missing part of the device name.
Signed-off-by: Shyam Prasad N
Reviewed-by: Aurelien Aptel
Signed-off-by: Steve French
Signed-off-by: Sasha Levin
Signed-off-by: Kamal Mostafa
Signed-off-by: Kelsey Skunberg
This has caused problems before, in bug 1923670, where we wrote to
upstream and had it reverted from upstream -stable and reverted it from
our kernels.
Having a look through the git history, I see the revert actually landed
in 4.15.0-144-generic, which has just landed in -updates (but not quite
yet in -security).
$ git log --grep "cifs: Set CIFS_MOUNT_USE_PREFIX_PATH flag on setting
cifs_sb->prepath." origin/master-next
commit 9f5e9a8722e0a6d1bf46a689ba4541e4377c4b0b
Author: Greg Kroah-Hartman
Date: Mon Apr 12 09:56:57 2021 +0200
Revert "cifs: Set CIFS_MOUNT_USE_PREFIX_PATH flag on setting
cifs_sb->prepath."
BugLink:
https://eur03.safelinks.protection.outlook.com/?url=https%3A%2F%2Fbugs.launchpad.net%2Fbugs%2F1926808data=04%7C01%7CChris.Ritson%40newcastle.ac.uk%7Cf393674c32b74f499e3e08d92644d8d4%7C9c5012c9b61644c2a91766814fbe3e87%7C1%7C0%7C637582900140610302%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000sdata=YGZSXrerrTJlSPyCf6P3jg1WIiPLJaG8Bk%2Bf0zCqY6w%3Dreserved=0
This reverts commit ad48c641e7c344ae7aba243d3056a22eaba71bfd which is
commit a738c93fb1c17e386a09304b517b1c6b2a6a5a8b upstream.
It is reported to cause problems in older kernels, so revert it for now
until we can figure it out...
Reported-by: Salvatore Bonaccorso
Link:
https://eur03.safelinks.protection.outlook.com/?url=https%3A%2F%2Flore.kernel.org%2Fr%2FYG7r0UaivWZL762N%40eldamar.landata=04%7C01%7CChris.Ritson%40newcastle.ac.uk%7Cf393674c32b74f499e3e08d92644d8d4%7C9c5012c9b61644c2a91766814fbe3e87%7C1%7C0%7C637582900140610302%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000sdata=nyKOGehTRXTa5LXaFJPOxJrvTqm4GC91uNmMVmDLbSs%3Dreserved=0
Cc: Shyam Prasad N
Cc: Aurelien Aptel
Cc: Steve French
Cc: Sasha Levin
Signed-off-by: Greg Kroah-Hartman
Signed-off-by: Kamal Mostafa
Signed-off-by: Stefan Bader
$ git describe --contains 9f5e9a8722e0a6d1bf46a689ba4541e4377c4b0b
Ubuntu-4.15.0-144.148~25
Could you please try 4.15.0-144-generic and let me know if it fixes it
for you? It should be fixed there.
Thanks,
Matthew
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