If a process opening a file is killed while waiting for a SMB2_CREATE
response from the server, the response may not be handled by the client,
leaking an open file handle on the server.
This can be reproduced with the following:
# mount //vm3/user1 /mnt/vm3 -overs=3,sec=ntlmssp,credentials=/root/.user1_smb_creds
# cd /mnt/vm3
# echo foo > foo
# for i in {1..100} ; do cat foo >/dev/null 2>&1 & sleep 0.0001 ; kill -9 $! ; done
(increase count if necessary--100 appears sufficient to cause multiple leaked file handles)
The client will stop waiting for the response, and will output
the following when the response does arrive:
CIFS VFS: Close unmatched open
on the server side, an open file handle is leaked. If using samba,
the following will show these open files:
# smbstatus | grep -i Locked -A1000
Locked files:
Pid Uid DenyMode Access R/W Oplock SharePath Name Time
--------------------------------------------------------------------------------------------------
25936 501 DENY_NONE 0x80 RDONLY NONE /home/user1 . Tue Nov 12 12:29:24 2019
25936 501 DENY_NONE 0x80 RDONLY NONE /home/user1 . Tue Nov 12 12:29:24 2019
25936 501 DENY_NONE 0x120089 RDONLY LEASE(RWH) /home/user1 foo Tue Nov 12 12:29:24 2019
25936 501 DENY_NONE 0x120089 RDONLY LEASE(RWH) /home/user1 foo Tue Nov 12 12:29:24 2019
25936 501 DENY_NONE 0x120089 RDONLY LEASE(RWH) /home/user1 foo Tue Nov 12 12:29:24 2019
25936 501 DENY_NONE 0x120089 RDONLY LEASE(RWH) /home/user1 foo Tue Nov 12 12:29:24 2019
25936 501 DENY_NONE 0x120089 RDONLY LEASE(RWH) /home/user1 foo Tue Nov 12 12:29:24 2019
(also tracked https://bugzilla.redhat.com/show_bug.cgi?id=1771691)
Frank
--
Frank Sorenson
sorenson@xxxxxxxxxx
Principal Software Maintenance Engineer
Global Support Services - filesystems
Red Hat
