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* nfsd4: allow encoding across page boundariesJ. Bruce Fields2014-05-301-0/+1
| | | | | | | | | | | After this we can handle for example getattr of very large ACLs. Read, readdir, readlink are still special cases with their own limits. Also we can't handle a new operation starting close to the end of a page. Signed-off-by: J. Bruce Fields <bfields@redhat.com>
* SUNRPC: Fix a module reference leak in svc_handle_xprtTrond Myklebust2014-05-221-0/+2
| | | | | | | | If the accept() call fails, we need to put the module reference. Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com> Cc: stable@vger.kernel.org Signed-off-by: J. Bruce Fields <bfields@redhat.com>
* NFSD: Ignore client's source port on RDMA transportsChuck Lever2014-05-221-1/+1
| | | | | | | | | | | | | | | | | | | An NFS/RDMA client's source port is meaningless for RDMA transports. The transport layer typically sets the source port value on the connection to a random ephemeral port. Currently, NFS server administrators must specify the "insecure" export option to enable clients to access exports via RDMA. But this means NFS clients can access such an export via IP using an ephemeral port, which may not be desirable. This patch eliminates the need to specify the "insecure" export option to allow NFS/RDMA clients access to an export. BugLink: https://bugzilla.linux-nfs.org/show_bug.cgi?id=250 Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
* net: Mark functions as static in net/sunrpc/svc_xprt.cRashika Kheria2014-02-091-3/+3
| | | | | | | | | | | | | | Mark functions as static in net/sunrpc/svc_xprt.c because they are not used outside this file. This eliminates the following warning in net/sunrpc/svc_xprt.c: net/sunrpc/svc_xprt.c:574:5: warning: no previous prototype for ‘svc_alloc_arg’ [-Wmissing-prototypes] net/sunrpc/svc_xprt.c:615:18: warning: no previous prototype for ‘svc_get_next_xprt’ [-Wmissing-prototypes] net/sunrpc/svc_xprt.c:694:6: warning: no previous prototype for ‘svc_add_new_temp_xprt’ [-Wmissing-prototypes] Signed-off-by: Rashika Kheria <rashika.kheria@gmail.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org> Signed-off-by: David S. Miller <davem@davemloft.net>
* svcrpc: fix rpc server shutdown racesJ. Bruce Fields2013-02-171-25/+32
| | | | | | | | | | | | | | | | | | | | Rewrite server shutdown to remove the assumption that there are no longer any threads running (no longer true, for example, when shutting down the service in one network namespace while it's still running in others). Do that by doing what we'd do in normal circumstances: just CLOSE each socket, then enqueue it. Since there may not be threads to handle the resulting queued xprts, also run a simplified version of the svc_recv() loop run by a server to clean up any closed xprts afterwards. Cc: stable@kernel.org Tested-by: Jason Tibbitts <tibbs@math.uh.edu> Tested-by: Paweł Sikora <pawel.sikora@agmk.net> Acked-by: Stanislav Kinsbursky <skinsbursky@parallels.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
* svcrpc: make svc_age_temp_xprts enqueue under sv_lockJ. Bruce Fields2013-02-171-13/+2
| | | | | | | | | | | | | | | | | svc_age_temp_xprts expires xprts in a two-step process: first it takes the sv_lock and moves the xprts to expire off their server-wide list (sv_tempsocks or sv_permsocks) to a local list. Then it drops the sv_lock and enqueues and puts each one. I see no reason for this: svc_xprt_enqueue() will take sp_lock, but the sv_lock and sp_lock are not otherwise nested anywhere (and documentation at the top of this file claims it's correct to nest these with sp_lock inside.) Cc: stable@kernel.org Tested-by: Jason Tibbitts <tibbs@math.uh.edu> Tested-by: Paweł Sikora <pawel.sikora@agmk.net> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
* sunrpc: Fix lockd sleeping until timeoutAndriy Skulysh2013-01-231-1/+8
| | | | | | | | | | | There is a race in enqueueing thread to a pool and waking up a thread. lockd doesn't wake up on reception of lock granted callback if svc_wake_up() is called before lockd's thread is added to a pool. Signed-off-by: Andriy Skulysh <Andriy_Skulysh@xyratex.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
* SUNRPC: remove BUG_ON in svc_delete_xprtWeston Andros Adamson2012-11-041-1/+1
| | | | | | | Replace BUG_ON() with WARN_ON_ONCE(). Signed-off-by: Weston Andros Adamson <dros@netapp.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
* SUNRPC: remove BUG_ONs checking RPCSVC_MAXPAGESWeston Andros Adamson2012-11-041-1/+4
| | | | | | | | Replace two bounds checking BUG_ON() calls with WARN_ON_ONCE() and resetting the requested size to RPCSVC_MAXPAGES. Signed-off-by: Weston Andros Adamson <dros@netapp.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
* SUNRPC: remove BUG_ON in svc_xprt_receivedWeston Andros Adamson2012-11-041-1/+3
| | | | | | | Replace BUG_ON() with a WARN_ON_ONCE() and early return. Signed-off-by: Weston Andros Adamson <dros@netapp.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
* svcrpc: split up svc_handle_xprtJ. Bruce Fields2012-08-211-22/+25
| | | | | | Move initialization of newly accepted socket into a helper. Signed-off-by: J. Bruce Fields <bfields@redhat.com>
* svcrpc: break up svc_recvJ. Bruce Fields2012-08-211-36/+67
| | | | | | | | | | | | Matter of taste, I suppose, but svc_recv breaks up naturally into: allocate pages and setup arg dequeue (wait for, if necessary) next socket do something with that socket And I find it easier to read when it doesn't go on for pages and pages. Signed-off-by: J. Bruce Fields <bfields@redhat.com>
* svcrpc: make svc_xprt_received staticJ. Bruce Fields2012-08-211-21/+20
| | | | | | | | | | Note this isn't used outside svc_xprt.c. May as well move it so we don't need a declaration while we're here. Also remove an outdated comment. Signed-off-by: J. Bruce Fields <bfields@redhat.com>
* svcrpc: make xpo_recvfrom return only >=0J. Bruce Fields2012-08-211-1/+1
| | | | | | | | | | The only errors returned from xpo_recvfrom have been -EAGAIN and -EAFNOSUPPORT. The latter was removed by a previous patch. That leaves only -EAGAIN, which is treated just like 0 by the caller (svc_recv). So, just ditch -EAGAIN and return 0 instead. Signed-off-by: J. Bruce Fields <bfields@redhat.com>
* svcrpc: share some setup of listening socketsJ. Bruce Fields2012-08-211-6/+10
| | | | | | There's some duplicate code here. Signed-off-by: J. Bruce Fields <bfields@redhat.com>
* svcrpc: make svc_create_xprt enqueue on clearing XPT_BUSYJ. Bruce Fields2012-08-211-1/+1
| | | | | | | | Whenever we clear XPT_BUSY we should call svc_xprt_enqueue(). Without that we may fail to notice any events (such as new connections) that arrived while XPT_BUSY was set. Signed-off-by: J. Bruce Fields <bfields@redhat.com>
* svcrpc: fix xpt_list traversal locking on shutdownJ. Bruce Fields2012-08-211-9/+15
| | | | | | | Server threads are not running at this point, but svc_age_temp_xprts still may be, so we need this locking. Signed-off-by: J. Bruce Fields <bfields@redhat.com>
* svcrpc: fix svc_xprt_enqueue/svc_recv busy-loopingJ. Bruce Fields2012-08-201-5/+2
| | | | | | | | | | | | | | | | | | | | | | | The rpc server tries to ensure that there will be room to send a reply before it receives a request. It does this by tracking, in xpt_reserved, an upper bound on the total size of the replies that is has already committed to for the socket. Currently it is adding in the estimate for a new reply *before* it checks whether there is space available. If it finds that there is not space, it then subtracts the estimate back out. This may lead the subsequent svc_xprt_enqueue to decide that there is space after all. The results is a svc_recv() that will repeatedly return -EAGAIN, causing server threads to loop without doing any actual work. Cc: stable@vger.kernel.org Reported-by: Michael Tokarev <mjt@tls.msk.ru> Tested-by: Michael Tokarev <mjt@tls.msk.ru> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
* svcrpc: sends on closed socket should stop immediatelyJ. Bruce Fields2012-08-201-1/+2
| | | | | | | | | | | | | | | | | | | svc_tcp_sendto sets XPT_CLOSE if we fail to transmit the entire reply. However, the XPT_CLOSE won't be acted on immediately. Meanwhile other threads could send further replies before the socket is really shut down. This can manifest as data corruption: for example, if a truncated read reply is followed by another rpc reply, that second reply will look to the client like further read data. Symptoms were data corruption preceded by svc_tcp_sendto logging something like kernel: rpc-srv/tcp: nfsd: sent only 963696 when sending 1048708 bytes - shutting down socket Cc: stable@vger.kernel.org Reported-by: Malahal Naineni <malahal@us.ibm.com> Tested-by: Malahal Naineni <malahal@us.ibm.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
* Merge branch 'for-3.5' of git://linux-nfs.org/~bfields/linuxLinus Torvalds2012-06-011-2/+2
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull the rest of the nfsd commits from Bruce Fields: "... and then I cherry-picked the remainder of the patches from the head of my previous branch" This is the rest of the original nfsd branch, rebased without the delegation stuff that I thought really needed to be redone. I don't like rebasing things like this in general, but in this situation this was the lesser of two evils. * 'for-3.5' of git://linux-nfs.org/~bfields/linux: (50 commits) nfsd4: fix, consolidate client_has_state nfsd4: don't remove rebooted client record until confirmation nfsd4: remove some dprintk's and a comment nfsd4: return "real" sequence id in confirmed case nfsd4: fix exchange_id to return confirm flag nfsd4: clarify that renewing expired client is a bug nfsd4: simpler ordering of setclientid_confirm checks nfsd4: setclientid: remove pointless assignment nfsd4: fix error return in non-matching-creds case nfsd4: fix setclientid_confirm same_cred check nfsd4: merge 3 setclientid cases to 2 nfsd4: pull out common code from setclientid cases nfsd4: merge last two setclientid cases nfsd4: setclientid/confirm comment cleanup nfsd4: setclientid remove unnecessary terms from a logical expression nfsd4: move rq_flavor into svc_cred nfsd4: stricter cred comparison for setclientid/exchange_id nfsd4: move principal name into svc_cred nfsd4: allow removing clients not holding state nfsd4: rearrange exchange_id logic to simplify ...
| * svcrpc: fix a comment typoJ. Bruce Fields2012-05-311-1/+1
| | | | | | | | Signed-off-by: J. Bruce Fields <bfields@redhat.com>
| * sunrpc: do array overrun check in svc_recv before allocating pagesJeff Layton2012-05-311-1/+1
| | | | | | | | | | | | | | | | | | | | There's little point in waiting until after we allocate all of the pages to see if we're going to overrun the array. In the event that this calculation is really off we could end up scribbling over a bunch of memory and make it tougher to debug. Signed-off-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
* | net: Convert net_ratelimit uses to net_<level>_ratelimitedJoe Perches2012-05-151-8/+5
|/ | | | | | | | | | Standardize the net core ratelimited logging functions. Coalesce formats, align arguments. Change a printk then vprintk sequence to use printf extension %pV. Signed-off-by: Joe Perches <joe@perches.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* SUNRPC: service destruction in network namespace contextStanislav Kinsbursky2012-02-151-10/+17
| | | | | | | | | | | | | | | v2: Added comment to BUG_ON's in svc_destroy() to make code looks clearer. This patch introduces network namespace filter for service destruction function. Nothing special here - just do exactly the same operations, but only for tranports in passed networks namespace context. BTW, BUG_ON() checks for empty service transports lists were returned into svc_destroy() function. This is because of swithing generic svc_close_all() to networks namespace dependable svc_close_net(). Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
* SUNRPC: clear svc transports lists helper introducedStanislav Kinsbursky2012-02-151-8/+11
| | | | | | | | | | This patch moves service transports deletion from service sockets lists to separated function. This is a precursor patch, which would be usefull with service shutdown in network namespace context, introduced later in the series. Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
* SUNRPC: clear svc pools lists helper introducedStanislav Kinsbursky2012-02-151-6/+13
| | | | | | | | | | | This patch moves removing of service transport from it's pools ready lists to separated function. Also this clear is now done with list_for_each_entry_safe() helper. This is a precursor patch, which would be usefull with service shutdown in network namespace context, introduced later in the series. Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
* SUNRPC: search for service transports in network namespace contextStanislav Kinsbursky2012-01-311-1/+5
| | | | | | | | | Service transports are parametrized by network namespace. And thus lookup of transport instance have to take network namespace into account. Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com> Acked-by: J. Bruce Fields <bfields@redhat.com>
* Merge branch 'for-3.3' of git://linux-nfs.org/~bfields/linuxLinus Torvalds2012-01-141-21/+41
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * 'for-3.3' of git://linux-nfs.org/~bfields/linux: (31 commits) nfsd4: nfsd4_create_clid_dir return value is unused NFSD: Change name of extended attribute containing junction svcrpc: don't revert to SVC_POOL_DEFAULT on nfsd shutdown svcrpc: fix double-free on shutdown of nfsd after changing pool mode nfsd4: be forgiving in the absence of the recovery directory nfsd4: fix spurious 4.1 post-reboot failures NFSD: forget_delegations should use list_for_each_entry_safe NFSD: Only reinitilize the recall_lru list under the recall lock nfsd4: initialize special stateid's at compile time NFSd: use network-namespace-aware cache registering routines SUNRPC: create svc_xprt in proper network namespace svcrpc: update outdated BKL comment nfsd41: allow non-reclaim open-by-fh's in 4.1 svcrpc: avoid memory-corruption on pool shutdown svcrpc: destroy server sockets all at once svcrpc: make svc_delete_xprt static nfsd: Fix oops when parsing a 0 length export nfsd4: Use kmemdup rather than duplicating its implementation nfsd4: add a separate (lockowner, inode) lookup nfsd4: fix CONFIG_NFSD_FAULT_INJECTION compile error ...
| * SUNRPC: create svc_xprt in proper network namespaceStanislav Kinsbursky2011-12-061-3/+3
| | | | | | | | | | | | | | This patch makes svc_xprt inherit network namespace link from its socket. Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
| * svcrpc: avoid memory-corruption on pool shutdownJ. Bruce Fields2011-12-061-19/+29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Socket callbacks use svc_xprt_enqueue() to add an xprt to a pool->sp_sockets list. In normal operation a server thread will later come along and take the xprt off that list. On shutdown, after all the threads have exited, we instead manually walk the sv_tempsocks and sv_permsocks lists to find all the xprt's and delete them. So the sp_sockets lists don't really matter any more. As a result, we've mostly just ignored them and hoped they would go away. Which has gotten us into trouble; witness for example ebc63e531cc6 "svcrpc: fix list-corrupting race on nfsd shutdown", the result of Ben Greear noticing that a still-running svc_xprt_enqueue() could re-add an xprt to an sp_sockets list just before it was deleted. The fix was to remove it from the list at the end of svc_delete_xprt(). But that only made corruption less likely--I can see nothing that prevents a svc_xprt_enqueue() from adding another xprt to the list at the same moment that we're removing this xprt from the list. In fact, despite the earlier xpo_detach(), I don't even see what guarantees that svc_xprt_enqueue() couldn't still be running on this xprt. So, instead, note that svc_xprt_enqueue() essentially does: lock sp_lock if XPT_BUSY unset add to sp_sockets unlock sp_lock So, if we do: set XPT_BUSY on every xprt. Empty every sp_sockets list, under the sp_socks locks. Then we're left knowing that the sp_sockets lists are all empty and will stay that way, since any svc_xprt_enqueue() will check XPT_BUSY under the sp_lock and see it set. And *then* we can continue deleting the xprt's. (Thanks to Jeff Layton for being correctly suspicious of this code....) Cc: Ben Greear <greearb@candelatech.com> Cc: Jeff Layton <jlayton@redhat.com> Cc: stable@kernel.org Signed-off-by: J. Bruce Fields <bfields@redhat.com>
| * svcrpc: destroy server sockets all at onceJ. Bruce Fields2011-12-061-1/+10
| | | | | | | | | | | | | | | | There's no reason I can see that we need to call sv_shutdown between closing the two lists of sockets. Cc: stable@kernel.org Signed-off-by: J. Bruce Fields <bfields@redhat.com>
| * svcrpc: make svc_delete_xprt staticJ. Bruce Fields2011-12-061-1/+2
| | | | | | | | Signed-off-by: J. Bruce Fields <bfields@redhat.com>
* | net: use IS_ENABLED(CONFIG_IPV6)Eric Dumazet2011-12-111-4/+4
|/ | | | | | | Instead of testing defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* net: Fix files explicitly needing to include module.hPaul Gortmaker2011-10-311-0/+1
| | | | | | | | | With calls to modular infrastructure, these files really needs the full module.h header. Call it out so some of the cleanups of implicit and unrequired includes elsewhere can be cleaned up. Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
* SUNRPC: Replace svc_addr_u by sockaddr_storageMi Jinlong2011-09-141-11/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | For IPv6 local address, lockd can not callback to client for missing scope id when binding address at inet6_bind: 324 if (addr_type & IPV6_ADDR_LINKLOCAL) { 325 if (addr_len >= sizeof(struct sockaddr_in6) && 326 addr->sin6_scope_id) { 327 /* Override any existing binding, if another one 328 * is supplied by user. 329 */ 330 sk->sk_bound_dev_if = addr->sin6_scope_id; 331 } 332 333 /* Binding to link-local address requires an interface */ 334 if (!sk->sk_bound_dev_if) { 335 err = -EINVAL; 336 goto out_unlock; 337 } Replacing svc_addr_u by sockaddr_storage, let rqstp->rq_daddr contains more info besides address. Reviewed-by: Jeff Layton <jlayton@redhat.com> Reviewed-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Mi Jinlong <mijinlong@cn.fujitsu.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
* svcrpc: fix list-corrupting race on nfsd shutdownJ. Bruce Fields2011-07-151-5/+6
| | | | | | | | | | | | | | | | | | | | | | After commit 3262c816a3d7fb1eaabce633caa317887ed549ae "[PATCH] knfsd: split svc_serv into pools", svc_delete_xprt (then svc_delete_socket) no longer removed its xpt_ready (then sk_ready) field from whatever list it was on, noting that there was no point since the whole list was about to be destroyed anyway. That was mostly true, but forgot that a few svc_xprt_enqueue()'s might still be hanging around playing with the about-to-be-destroyed list, and could get themselves into trouble writing to freed memory if we left this xprt on the list after freeing it. (This is actually functionally identical to a patch made first by Ben Greear, but with more comments.) Cc: stable@kernel.org Cc: gnb@fmeh.org Reported-by: Ben Greear <greearb@candelatech.com> Tested-by: Ben Greear <greearb@candelatech.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
* rpc: keep backchannel xprt as long as server connectionJ. Bruce Fields2011-01-111-0/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | Multiple backchannels can share the same tcp connection; from rfc 5661 section 2.10.3.1: A connection's association with a session is not exclusive. A connection associated with the channel(s) of one session may be simultaneously associated with the channel(s) of other sessions including sessions associated with other client IDs. However, multiple backchannels share a connection, they must all share the same xid stream (hence the same rpc_xprt); the only way we have to match replies with calls at the rpc layer is using the xid. So, keep the rpc_xprt around as long as the connection lasts, in case we're asked to use the connection as a backchannel again. Requests to create new backchannel clients over a given server connection should results in creating new clients that reuse the existing rpc_xprt. But to start, just reject attempts to associate multiple rpc_xprt's with the same underlying bc_xprt. Signed-off-by: J. Bruce Fields <bfields@redhat.com>
* svcrpc: simpler request droppingJ. Bruce Fields2011-01-041-0/+1
| | | | | | | | | | | | | | Currently we use -EAGAIN returns to determine when to drop a deferred request. On its own, that is error-prone, as it makes us treat -EAGAIN returns from other functions specially to prevent inadvertent dropping. So, use a flag on the request instead. Returning an error on request deferral is still required, to prevent further processing, but we no longer need worry that an error return on its own could result in a drop. Signed-off-by: J. Bruce Fields <bfields@redhat.com>
* sunrpc: remove xpt_poolNeilBrown2010-12-171-5/+0
| | | | | | | | | | | | | | | | | | | | | | | | | The xpt_pool field is only used for reporting BUGs. And it isn't used correctly. In particular, when it is cleared in svc_xprt_received before XPT_BUSY is cleared, there is no guarantee that either the compiler or the CPU might not re-order to two assignments, just setting xpt_pool to NULL after XPT_BUSY is cleared. If a different cpu were running svc_xprt_enqueue at this moment, it might see XPT_BUSY clear and then xpt_pool non-NULL, and so BUG. This could be fixed by calling smp_mb__before_clear_bit() before the clear_bit. However as xpt_pool isn't really used, it seems safest to simply remove xpt_pool. Another alternate would be to change the clear_bit to clear_bit_unlock, and the test_and_set_bit to test_and_set_bit_lock. Signed-off-by: NeilBrown <neilb@suse.de> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
* Merge commit 'v2.6.37-rc6' into for-2.6.38J. Bruce Fields2010-12-171-2/+8
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| * sunrpc: prevent use-after-free on clearing XPT_BUSYNeilBrown2010-12-071-1/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When an xprt is created, it has a refcount of 1, and XPT_BUSY is set. The refcount is *not* owned by the thread that created the xprt (as is clear from the fact that creators never put the reference). Rather, it is owned by the absence of XPT_DEAD. Once XPT_DEAD is set, (And XPT_BUSY is clear) that initial reference is dropped and the xprt can be freed. So when a creator clears XPT_BUSY it is dropping its only reference and so must not touch the xprt again. However svc_recv, after calling ->xpo_accept (and so getting an XPT_BUSY reference on a new xprt), calls svc_xprt_recieved. This clears XPT_BUSY and then svc_xprt_enqueue - this last without owning a reference. This is dangerous and has been seen to leave svc_xprt_enqueue working with an xprt containing garbage. So we need to hold an extra counted reference over that call to svc_xprt_received. For safety, any time we clear XPT_BUSY and then use the xprt again, we first get a reference, and the put it again afterwards. Note that svc_close_all does not need this extra protection as there are no threads running, and the final free can only be called asynchronously from such a thread. Signed-off-by: NeilBrown <neilb@suse.de> Cc: stable@kernel.org Signed-off-by: J. Bruce Fields <bfields@redhat.com>
| * BKL: remove extraneous #include <smp_lock.h>Arnd Bergmann2010-11-171-1/+0
| | | | | | | | | | | | | | | | | | | | The big kernel lock has been removed from all these files at some point, leaving only the #include. Remove this too as a cleanup. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | svcrpc: fix wspace-checking raceJ. Bruce Fields2010-11-191-22/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We call svc_xprt_enqueue() after something happens which we think may require handling from a server thread. To avoid such events being lost, svc_xprt_enqueue() must guarantee that there will be a svc_serv() call from a server thread following any such event. It does that by either waking up a server thread itself, or checking that XPT_BUSY is set (in which case somebody else is doing it). But the check of XPT_BUSY could occur just as someone finishes processing some other event, and just before they clear XPT_BUSY. Therefore it's important not to clear XPT_BUSY without subsequently doing another svc_export_enqueue() to check whether the xprt should be requeued. The xpo_wspace() check in svc_xprt_enqueue() breaks this rule, allowing an event to be missed in situations like: data arrives call svc_tcp_data_ready(): call svc_xprt_enqueue(): set BUSY find no write space svc_reserve(): free up write space call svc_enqueue(): test BUSY clear BUSY So, instead, check wspace in the same places that the state flags are checked: before taking BUSY, and in svc_receive(). Signed-off-by: J. Bruce Fields <bfields@redhat.com>
* | svcrpc: svc_close_xprt commentJ. Bruce Fields2010-11-191-1/+6
| | | | | | | | | | | | | | Neil Brown had to explain to me why we do this here; record the answer for posterity. Signed-off-by: J. Bruce Fields <bfields@redhat.com>
* | svcrpc: simplify svc_close_allJ. Bruce Fields2010-11-191-8/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There's no need to be fooling with XPT_BUSY now that all the threads are gone. The list_del_init() here could execute at the same time as the svc_xprt_enqueue()'s list_add_tail(), with undefined results. We don't really care at this point, but it might result in a spurious list-corruption warning or something. And svc_close() isn't adding any value; just call svc_delete_xprt() directly. Signed-off-by: J. Bruce Fields <bfields@redhat.com>
* | nfsd4: centralize more calls to svc_xprt_receivedJ. Bruce Fields2010-11-191-12/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Follow up on b48fa6b99100dc7772af3cd276035fcec9719ceb by moving all the svc_xprt_received() calls for the main xprt to one place. The clearing of XPT_BUSY here is critical to the correctness of the server, so I'd prefer it to be obvious where we do it. The only substantive result is moving svc_xprt_received() after svc_receive_deferred(). Other than a (likely insignificant) delay waking up the next thread, that should be harmless. Also reshuffle the exit code a little to skip a few other steps that we don't care about the in the svc_delete_xprt() case. Signed-off-by: J. Bruce Fields <bfields@redhat.com>
* | svcrpc: don't set then immediately clear XPT_DEFERREDJ. Bruce Fields2010-11-191-3/+2
|/ | | | | | | | | | There's no harm to doing this, since the only caller will immediately call svc_enqueue() afterwards, ensuring we don't miss the remaining deferred requests just because XPT_DEFERRED was briefly cleared. But why not just do this the simple way? Signed-off-by: J. Bruce Fields <bfields@redhat.com>
* svcrpc: no need for XPT_DEAD check in svc_xprt_enqueueJ. Bruce Fields2010-10-251-6/+0
| | | | | | | | If any xprt marked DEAD is also left BUSY for the rest of its life, then the XPT_DEAD check here is superfluous--we'll get the same result from the XPT_BUSY check just after. Signed-off-by: J. Bruce Fields <bfields@redhat.com>
* svcrpc: assume svc_delete_xprt() called only onceJ. Bruce Fields2010-10-251-1/+1
| | | | | | | | As long as DEAD exports are left BUSY, and svc_delete_xprt is called only with BUSY held, then svc_delete_xprt() will never be called on an xprt that is already DEAD. Signed-off-by: J. Bruce Fields <bfields@redhat.com>
* svcrpc: never clear XPT_BUSY on dead xprtJ. Bruce Fields2010-10-251-3/+0
| | | | | | | | | | | | Once an xprt has been deleted, there's no reason to allow it to be enqueued--at worst, that might cause the xprt to be re-added to some global list, resulting in later corruption. Also, note this leaves us with no need for the reference-count manipulation here. Reviewed-by: NeilBrown <neilb@suse.de> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
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