Bug 1593335

Summary: client: allow client to use caps that are revoked but not yet returned
Product: [Red Hat Storage] Red Hat Ceph Storage Reporter: Jeff Layton <jlayton>
Component: CephFSAssignee: Patrick Donnelly <pdonnell>
Status: CLOSED ERRATA QA Contact: Tejas <tchandra>
Severity: medium Docs Contact:
Priority: low    
Version: 3.0CC: ceph-eng-bugs, ceph-qe-bugs, john.spray, rperiyas, tchandra
Target Milestone: z5   
Target Release: 3.0   
Hardware: Unspecified   
OS: Unspecified   
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Fixed In Version: RHEL: ceph-12.2.4-32 Ubuntu: ceph_12.2.4-36redhat1xenial Doc Type: If docs needed, set a value
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Last Closed: 2018-08-09 18:27:13 UTC Type: Bug
Regression: --- Mount Type: ---
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description Jeff Layton 2018-06-20 15:07:40 UTC 
This fixes a problem with ganesha+cephfs and delegations:

caps_issued_mask is a function that we call to see if we have all of
the caps provided in a mask. Usually this ignores caps that have been
revoked by the MDS but that have not yet been released by the client.
These caps are still valid though -- nothing else can use them until
they've been released.

These codepaths call caps_issued_mask only in order to determine
whether the client holds enough caps to trust cached attributes. They
don't take new references to the caps, so it should be safe to use the
"implemented" capset in these functions.

This helps break a deadlock that can occur when the client holds a
delegation that has been recalled, but needs to satisfy a getattr
request before releasing it.


The PR has a testcase in it that tests this (LibCephFS.RecalledGetattr).
Comment 10 errata-xmlrpc 2018-08-09 18:27:13 UTC 
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHBA-2018:2375