Hi Bruce- > On Jun 22, 2018, at 1:54 PM, J. Bruce Fields <bfields@xxxxxxxxxxxx> wrote: > > On Thu, Jun 21, 2018 at 04:35:33PM +0000, Manjunath Patil wrote: >> Presently nfserr_jukebox is being returned by nfsd for create_session >> request if server is unable to allocate a session slot. This may be >> treated as NFS4ERR_DELAY by the clients and which may continue to re-try >> create_session in loop leading NFSv4.1+ mounts in hung state. nfsd >> should return nfserr_nospc in this case as per rfc5661(section-18.36.4 >> subpoint 4. Session creation). > > I don't think the spec actually gives us an error that we can use to say > a CREATE_SESSION failed permanently for lack of resources. The current situation is that the server replies NFS4ERR_DELAY, and the client retries indefinitely. The goal is to let the client choose whether it wants to try the CREATE_SESSION again, try a different NFS version, or fail the mount request. Bill and I both looked at this section of RFC 5661. It seems to us that the use of NFS4ERR_NOSPC is appropriate and unambiguous in this situation, and it is an allowed status for the CREATE_SESSION operation. NFS4ERR_DELAY OTOH is not helpful. > Better would be to avoid the need to fail at all. That would be good too. > Possibilities: > > - revive Trond's patches some time back to do dynamic slot size > renegotiation > - make sure the systems you're testing on already have > de766e570413 and 44d8660d3bb0 applied. > - further liberalise the limits here: do we need them at all, or > should we just wait till a kmalloc fails? Or maybe take a > hybrid approach?: e.g. allow an arbitrary number of clients > and only limit slots & slotsizes. > --b. > >> >> Signed-off-by: Manjunath Patil <manjunath.b.patil@xxxxxxxxxx> >> --- >> fs/nfsd/nfs4state.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c >> index 8571414..3734e08 100644 >> --- a/fs/nfsd/nfs4state.c >> +++ b/fs/nfsd/nfs4state.c >> @@ -2716,7 +2716,7 @@ static __be32 check_forechannel_attrs(struct nfsd4_channel_attrs *ca, struct nfs >> */ >> ca->maxreqs = nfsd4_get_drc_mem(ca); >> if (!ca->maxreqs) >> - return nfserr_jukebox; >> + return nfserr_nospc; >> >> return nfs_ok; >> } >> -- >> 1.8.3.1 >> >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-nfs" in >> the body of a message to majordomo@xxxxxxxxxxxxxxx >> More majordomo info at http://vger.kernel.org/majordomo-info.html > -- > To unsubscribe from this list: send the line "unsubscribe linux-nfs" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- Chuck Lever chucklever@xxxxxxxxx -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
