On Thu, Oct 31, 2019 at 11:27 AM Olga Kornievskaia <aglo@xxxxxxxxx> wrote: > > Hi Trond, > > This patch set produces the following in my testing. Basically what I > see the client is prevented from using a delegation at all. > > After I induce a race of DELEGRETURN/OPEN > --- the racing OPEN gets a delegation (it returns the same seqid and > other as the delegation being returned) but the client doesn't use it. > --- the following (next) OPEN that also gets a delegation immediately > has the client returning the given delegation. > > Disclaimer: in my testing the racing DELEGRETURN doesn't fail with > OLD_STATEID, NetApp returns OK. Testing the same against Linux. It prevents the client from using future delegation stateid. On the induced DELEGRETURN/OPEN race, the linux server doesn't give a new read delegation. The following open gets a read delegation and returns it right away. > On Thu, Oct 24, 2019 at 6:56 AM Trond Myklebust <trondmy@xxxxxxxxx> wrote: > > > > The following patchset fixes up a number of issues with delegations, > > but mainly attempts to fix a race condition between open and > > delegreturn, where the open and the delegreturn get re-ordered so > > that the delegreturn ends up revoking the delegation that was returned > > by the open. > > The root cause is that in certain circumstances, we may currently end > > up freeing the delegation from delegreturn, so when we later receive > > the reply to the open, we've lost track of the fact that the seqid > > predates the one that was returned. > > > > This patchset fixes that case by ensuring that we always keep track > > of the last delegation stateid that was returned for any given inode. > > That way, if we later see a delegation stateid with the same opaque > > field, but an older seqid, we know we cannot trust it, and so we > > ask to replay the OPEN compound. > > > > Trond Myklebust (14): > > NFSv4: Don't allow a cached open with a revoked delegation > > NFSv4: Fix delegation handling in update_open_stateid() > > NFSv4: nfs4_callback_getattr() should ignore revoked delegations > > NFSv4: Delegation recalls should not find revoked delegations > > NFSv4: fail nfs4_refresh_delegation_stateid() when the delegation was > > revoked > > NFS: Rename nfs_inode_return_delegation_noreclaim() > > NFSv4: Don't remove the delegation from the super_list more than once > > NFSv4: Hold the delegation spinlock when updating the seqid > > NFSv4: Clear the NFS_DELEGATION_REVOKED flag in > > nfs_update_inplace_delegation() > > NFSv4: Update the stateid seqid in nfs_revoke_delegation() > > NFSv4: Revoke the delegation on success in nfs4_delegreturn_done() > > NFSv4: Ignore requests to return the delegation if it was revoked > > NFSv4: Don't reclaim delegations that have been returned or revoked > > NFSv4: Fix races between open and delegreturn > > > > fs/nfs/callback_proc.c | 2 +- > > fs/nfs/delegation.c | 109 +++++++++++++++++++++++++++++------------ > > fs/nfs/delegation.h | 4 +- > > fs/nfs/nfs4proc.c | 13 ++--- > > fs/nfs/nfs4super.c | 4 +- > > 5 files changed, 88 insertions(+), 44 deletions(-) > > > > -- > > 2.21.0 > >
