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2022-05-23SUNRPC: Use RMW bitops in single-threaded hot pathsChuck Lever1-3/+3
I noticed CPU pipeline stalls while using perf. Once an svc thread is scheduled and executing an RPC, no other processes will touch svc_rqst::rq_flags. Thus bus-locked atomics are not needed outside the svc thread scheduler. Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2022-05-19SUNRPC: Simplify synopsis of svc_pool_for_cpu()Chuck Lever1-6/+12
Clean up: There is one caller. The @cpu argument can be made implicit now that a get_cpu/put_cpu pair is no longer needed. Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2022-02-28NFSD: Move svc_serv_ops::svo_function into struct svc_servChuck Lever1-11/+26
Hoist svo_function back into svc_serv and remove struct svc_serv_ops, since the struct is now devoid of fields. Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2022-02-28NFSD: Remove svc_serv_ops::svo_moduleChuck Lever1-2/+0
struct svc_serv_ops is about to be removed. Neil Brown says: > I suspect svo_module can go as well - I don't think the thread is > ever the thing that primarily keeps a module active. A random sample of kthread_create() callers shows sunrpc is the only one that manages module reference count in this way. Suggested-by: Neil Brown <neilb@suse.de> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2022-02-28SUNRPC: Remove svc_shutdown_net()Chuck Lever1-6/+0
Clean up: svc_shutdown_net() now does nothing but call svc_close_net(). Replace all external call sites. svc_close_net() is renamed to be the inverse of svc_xprt_create(). Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2022-02-28SUNRPC: Rename svc_close_xprt()Chuck Lever1-1/+1
Clean up: Use the "svc_xprt_<task>" function naming convention as is used for other external APIs. Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2022-02-28SUNRPC: Remove svo_shutdown methodChuck Lever1-3/+0
Clean up. Neil observed that "any code that calls svc_shutdown_net() knows what the shutdown function should be, and so can call it directly." Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Reviewed-by: NeilBrown <neilb@suse.de>
2021-12-13lockd: use svc_set_num_threads() for thread start and stopNeilBrown1-2/+1
svc_set_num_threads() does everything that lockd_start_svc() does, except set sv_maxconn. It also (when passed 0) finds the threads and stops them with kthread_stop(). So move the setting for sv_maxconn, and use svc_set_num_thread() We now don't need nlmsvc_task. Now that we use svc_set_num_threads() it makes sense to set svo_module. This request that the thread exists with module_put_and_exit(). Also fix the documentation for svo_module to make this explicit. svc_prepare_thread is now only used where it is defined, so it can be made static. Signed-off-by: NeilBrown <neilb@suse.de> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2021-12-13SUNRPC: always treat sv_nrpools==1 as "not pooled"NeilBrown1-25/+29
Currently 'pooled' services hold a reference on the pool_map, and 'unpooled' services do not. svc_destroy() uses the presence of ->svo_function (via svc_serv_is_pooled()) to determine if the reference should be dropped. There is no direct correlation between being pooled and the use of svo_function, though in practice, lockd is the only non-pooled service, and the only one not to use svo_function. This is untidy and would cause problems if we changed lockd to use svc_set_num_threads(), which requires the use of ->svo_function. So change the test for "is the service pooled" to "is sv_nrpools > 1". This means that when svc_pool_map_get() returns 1, it must NOT take a reference to the pool. We discard svc_serv_is_pooled(), and test sv_nrpools directly. Signed-off-by: NeilBrown <neilb@suse.de> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2021-12-13SUNRPC: move the pool_map definitions (back) into svc.cNeilBrown1-6/+25
These definitions are not used outside of svc.c, and there is no evidence that they ever have been. So move them into svc.c and make the declarations 'static'. Signed-off-by: NeilBrown <neilb@suse.de> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2021-12-13SUNRPC: discard svo_setup and rename svc_set_num_threads_sync()NeilBrown1-47/+2
The ->svo_setup callback serves no purpose. It is always called from within the same module that chooses which callback is needed. So discard it and call the relevant function directly. Now that svc_set_num_threads() is no longer used remove it and rename svc_set_num_threads_sync() to remove the "_sync" suffix. Signed-off-by: NeilBrown <neilb@suse.de> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2021-12-13SUNRPC: use sv_lock to protect updates to sv_nrthreads.NeilBrown1-2/+7
Using sv_lock means we don't need to hold the service mutex over these updates. In particular, svc_exit_thread() no longer requires synchronisation, so threads can exit asynchronously. Note that we could use an atomic_t, but as there are many more read sites than writes, that would add unnecessary noise to the code. Some reads are already racy, and there is no need for them to not be. Signed-off-by: NeilBrown <neilb@suse.de> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2021-12-13SUNRPC: stop using ->sv_nrthreads as a refcountNeilBrown1-11/+11
The use of sv_nrthreads as a general refcount results in clumsy code, as is seen by various comments needed to explain the situation. This patch introduces a 'struct kref' and uses that for reference counting, leaving sv_nrthreads to be a pure count of threads. The kref is managed particularly in svc_get() and svc_put(), and also nfsd_put(); svc_destroy() now takes a pointer to the embedded kref, rather than to the serv. nfsd allows the svc_serv to exist with ->sv_nrhtreads being zero. This happens when a transport is created before the first thread is started. To support this, a 'keep_active' flag is introduced which holds a ref on the svc_serv. This is set when any listening socket is successfully added (unless there are running threads), and cleared when the number of threads is set. So when the last thread exits, the nfs_serv will be destroyed. The use of 'keep_active' replaces previous code which checked if there were any permanent sockets. We no longer clear ->rq_server when nfsd() exits. This was done to prevent svc_exit_thread() from calling svc_destroy(). Instead we take an extra reference to the svc_serv to prevent svc_destroy() from being called. Signed-off-by: NeilBrown <neilb@suse.de> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2021-12-13SUNRPC/NFSD: clean up get/put functions.NeilBrown1-14/+5
svc_destroy() is poorly named - it doesn't necessarily destroy the svc, it might just reduce the ref count. nfsd_destroy() is poorly named for the same reason. This patch: - removes the refcount functionality from svc_destroy(), moving it to a new svc_put(). Almost all previous callers of svc_destroy() now call svc_put(). - renames nfsd_destroy() to nfsd_put() and improves the code, using the new svc_destroy() rather than svc_put() - removes a few comments that explain the important for balanced get/put calls. This should be obvious. The only non-trivial part of this is that svc_destroy() would call svc_sock_update() on a non-final decrement. It can no longer do that, and svc_put() isn't really a good place of it. This call is now made from svc_exit_thread() which seems like a good place. This makes the call *before* sv_nrthreads is decremented rather than after. This is not particularly important as the call just sets a flag which causes sv_nrthreads set be checked later. A subsequent patch will improve the ordering. Signed-off-by: NeilBrown <neilb@suse.de> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2021-10-12SUNRPC: De-duplicate .pc_release() call sitesChuck Lever1-15/+7
There was some spaghetti in svc_process_common() that had evolved over time such that there was still one case that needed a call to .pc_release() but never made it. That issue was removed in the previous patch. As additional insurance against missing this important callout, ensure that the .pc_release() method is always called, no matter what the reply_stat is. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2021-10-12SUNRPC: Simplify the SVC dispatch code pathChuck Lever1-49/+2
Micro-optimization: The last user of the generic SVC dispatch code path has been removed, so svc_process_common() can be simplified. This declutters the hot path so that the by-far most common case (a dispatch function exists) is made the /only/ path. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2021-10-02NFSD: Have legacy NFSD WRITE decoders use xdr_stream_subsegment()Chuck Lever1-5/+6
Refactor. Now that the NFSv2 and NFSv3 XDR decoders have been converted to use xdr_streams, the WRITE decoder functions can use xdr_stream_subsegment() to extract the WRITE payload into its own xdr_buf, just as the NFSv4 WRITE XDR decoder currently does. That makes it possible to pass the first kvec, pages array + length, page_base, and total payload length via a single function parameter. The payload's page_base is not yet assigned or used, but will be in subsequent patches. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2021-09-04Merge tag 'nfs-for-5.15-1' of git://git.linux-nfs.org/projects/anna/linux-nfsLinus Torvalds1-28/+11
Pull NFS client updates from Anna Schumaker: "New Features: - Better client responsiveness when server isn't replying - Use refcount_t in sunrpc rpc_client refcount tracking - Add srcaddr and dst_port to the sunrpc sysfs info files - Add basic support for connection sharing between servers with multiple NICs` Bugfixes and Cleanups: - Sunrpc tracepoint cleanups - Disconnect after ib_post_send() errors to avoid deadlocks - Fix for tearing down rpcrdma_reps - Fix a potential pNFS layoutget livelock loop - pNFS layout barrier fixes - Fix a potential memory corruption in rpc_wake_up_queued_task_set_status() - Fix reconnection locking - Fix return value of get_srcport() - Remove rpcrdma_post_sends() - Remove pNFS dead code - Remove copy size restriction for inter-server copies - Overhaul the NFS callback service - Clean up sunrpc TCP socket shutdowns - Always provide aligned buffers to RPC read layers" * tag 'nfs-for-5.15-1' of git://git.linux-nfs.org/projects/anna/linux-nfs: (39 commits) NFS: Always provide aligned buffers to the RPC read layers NFSv4.1 add network transport when session trunking is detected SUNRPC enforce creation of no more than max_connect xprts NFSv4 introduce max_connect mount options SUNRPC add xps_nunique_destaddr_xprts to xprt_switch_info in sysfs SUNRPC keep track of number of transports to unique addresses NFSv3: Delete duplicate judgement in nfs3_async_handle_jukebox SUNRPC: Tweak TCP socket shutdown in the RPC client SUNRPC: Simplify socket shutdown when not reusing TCP ports NFSv4.2: remove restriction of copy size for inter-server copy. NFS: Clean up the synopsis of callback process_op() NFS: Extract the xdr_init_encode/decode() calls from decode_compound NFS: Remove unused callback void decoder NFS: Add a private local dispatcher for NFSv4 callback operations SUNRPC: Eliminate the RQ_AUTHERR flag SUNRPC: Set rq_auth_stat in the pg_authenticate() callout SUNRPC: Add svc_rqst::rq_auth_stat SUNRPC: Add dst_port to the sysfs xprt info file SUNRPC: Add srcaddr as a file in sysfs sunrpc: Fix return value of get_srcport() ...
2021-08-20SUNRPC: Server-side disconnect injectionChuck Lever1-0/+8
Disconnect injection stress-tests the ability for both client and server implementations to behave resiliently in the face of network instability. A file called /sys/kernel/debug/fail_sunrpc/ignore-server-disconnect enables administrators to turn off server-side disconnect injection while allowing other types of sunrpc errors to be injected. The default setting is that server-side disconnect injection is enabled (ignore=false). Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2021-08-17SUNRPC: Fix a NULL pointer deref in trace_svc_stats_latency()Chuck Lever1-0/+15
Some paths through svc_process() leave rqst->rq_procinfo set to NULL, which triggers a crash if tracing happens to be enabled. Fixes: 89ff87494c6e ("SUNRPC: Display RPC procedure names instead of proc numbers") Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2021-08-17SUNRPC: Add svc_rqst_replace_page() APIChuck Lever1-0/+21
Replacing a page in rq_pages[] requires a get_page(), which is a bus-locked operation, and a put_page(), which can be even more costly. To reduce the cost of replacing a page in rq_pages[], batch the put_page() operations by collecting "freed" pages in a pagevec, and then release those pages when the pagevec is full. This pagevec is also emptied when each RPC completes. Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2021-08-10SUNRPC: Eliminate the RQ_AUTHERR flagChuck Lever1-20/+4
Now that there is an alternate method for returning an auth_stat value, replace the RQ_AUTHERR flag with use of that new method. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2021-08-10SUNRPC: Set rq_auth_stat in the pg_authenticate() calloutChuck Lever1-3/+1
In a few moments, rq_auth_stat will need to be explicitly set to rpc_auth_ok before execution gets to the dispatcher. svc_authenticate() already sets it, but it often gets reset to rpc_autherr_badcred right after that call, even when authentication is successful. Let's ensure that the pg_authenticate callout and svc_set_client() set it properly in every case. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2021-08-10SUNRPC: Add svc_rqst::rq_auth_statChuck Lever1-8/+9
I'd like to take commit 4532608d71c8 ("SUNRPC: Clean up generic dispatcher code") even further by using only private local SVC dispatchers for all kernel RPC services. This change would enable the removal of the logic that switches between svc_generic_dispatch() and a service's private dispatcher, and simplify the invocation of the service's pc_release method so that humans can visually verify that it is always invoked properly. All that will come later. First, let's provide a better way to return authentication errors from SVC dispatcher functions. Instead of overloading the dispatch method's *statp argument, add a field to struct svc_rqst that can hold an error value. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2021-04-23SUNRPC: Fix null pointer dereference in svc_rqst_free()Yunjian Wang1-1/+2
When alloc_pages_node() returns null in svc_rqst_alloc(), the null rq_scratch_page pointer will be dereferenced when calling put_page() in svc_rqst_free(). Fix it by adding a null check. Addresses-Coverity: ("Dereference after null check") Fixes: 5191955d6fc6 ("SUNRPC: Prepare for xdr_stream-style decoding on the server-side") Signed-off-by: Yunjian Wang <wangyunjian@huawei.com> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2021-03-07sunrpc: fix refcount leak for rpc auth modulesDaniel Kobras1-2/+4
If an auth module's accept op returns SVC_CLOSE, svc_process_common() enters a call path that does not call svc_authorise() before leaving the function, and thus leaks a reference on the auth module's refcount. Hence, make sure calls to svc_authenticate() and svc_authorise() are paired for all call paths, to make sure rpc auth modules can be unloaded. Signed-off-by: Daniel Kobras <kobras@puzzle-itc.de> Fixes: 4d712ef1db05 ("svcauth_gss: Close connection when dropping an incoming message") Link: https://lore.kernel.org/linux-nfs/3F1B347F-B809-478F-A1E9-0BE98E22B0F0@oracle.com/T/#t Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2021-01-25SUNRPC: Correct a commentChuck Lever1-1/+1
Clean up: The rq_argpages field was removed from struct svc_rqst in the pre-git era. Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2020-11-30SUNRPC: Prepare for xdr_stream-style decoding on the server-sideChuck Lever1-0/+5
A "permanent" struct xdr_stream is allocated in struct svc_rqst so that it is usable by all server-side decoders. A per-rqst scratch buffer is also allocated to handle decoding XDR data items that cross page boundaries. To demonstrate how it will be used, add the first call site for the new svcxdr_init_decode() API. As an additional part of the overall conversion, add symbolic constants for successful and failed XDR operations. Returning "0" is overloaded. Sometimes it means something failed, but sometimes it means success. To make it more clear when XDR decoding functions succeed or fail, introduce symbolic constants. Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2020-11-30SUNRPC: Rename svc_encode_read_payload()Chuck Lever1-5/+6
Clean up: "result payload" is a less confusing name for these payloads. "READ payload" reflects only the NFS usage. Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2020-05-21Merge branch 'nfsd-5.8' of git://linux-nfs.org/~cel/cel-2.6 into ↵J. Bruce Fields1-15/+4
for-5.8-incoming Highlights of this series: * Remove serialization of sending RPC/RDMA Replies * Convert the TCP socket send path to use xdr_buf::bvecs (pre-requisite for RPC-on-TLS) * Fix svcrdma backchannel sendto return code * Convert a number of dprintk call sites to use tracepoints * Fix the "suggest braces around empty body in an 'else' statement" warning
2020-05-18SUNRPC: Trace server-side rpcbind registration eventsChuck Lever1-15/+4
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2020-05-12sunrpc: add missing newline when printing parameter 'pool_mode' by sysfsXiongfeng Wang1-5/+5
When I cat parameter '/sys/module/sunrpc/parameters/pool_mode', it displays as follows. It is better to add a newline for easy reading. [root@hulk-202 ~]# cat /sys/module/sunrpc/parameters/pool_mode global[root@hulk-202 ~]# Signed-off-by: Xiongfeng Wang <wangxiongfeng2@huawei.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2020-03-16SUNRPC: Teach server to use xprt_sock_sendmsg for socket sendsChuck Lever1-4/+0
xprt_sock_sendmsg uses the more efficient iov_iter-enabled kernel socket API, and is a pre-requisite for server send-side support for TLS. Note that svc_process no longer needs to reserve a word for the stream record marker, since the TCP transport now provides the record marker automatically in a separate buffer. The dprintk() in svc_send_common is also removed. It didn't seem crucial for field troubleshooting. If more is needed there, a trace point could be added in xprt_sock_sendmsg(). Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2020-03-16nfsd: Fix NFSv4 READ on RDMA when using readvChuck Lever1-0/+16
svcrdma expects that the payload falls precisely into the xdr_buf page vector. This does not seem to be the case for nfsd4_encode_readv(). This code is called only when fops->splice_read is missing or when RQ_SPLICE_OK is clear, so it's not a noticeable problem in many common cases. Add new transport method: ->xpo_read_payload so that when a READ payload does not fit exactly in rq_res's page vector, the XDR encoder can inform the RPC transport exactly where that payload is, without the payload's XDR pad. That way, when a Write chunk is present, the transport knows what byte range in the Reply message is supposed to be matched with the chunk. Note that the Linux NFS server implementation of NFS/RDMA can currently handle only one Write chunk per RPC-over-RDMA message. This simplifies the implementation of this fix. Fixes: b04209806384 ("nfsd4: allow exotic read compounds") Buglink: https://bugzilla.kernel.org/show_bug.cgi?id=198053 Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2019-10-30SUNRPC: Trace gssproxy upcall resultsChuck Lever1-0/+2
Record results of a GSS proxy ACCEPT_SEC_CONTEXT upcall and the svc_authenticate() function to make field debugging of NFS server Kerberos issues easier. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Reviewed-by: Bill Baker <bill.baker@oracle.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2019-09-25sunrpc: clean up indentation issueColin Ian King1-2/+2
There are statements that are indented incorrectly, remove the extraneous spacing. Signed-off-by: Colin Ian King <colin.king@canonical.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2019-07-18SUNRPC: Fix up backchannel slot table accountingTrond Myklebust1-1/+1
Add a per-transport maximum limit in the socket case, and add helpers to allow the NFSv4 code to discover that limit. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2019-05-21treewide: Add SPDX license identifier for missed filesThomas Gleixner1-0/+1
Add SPDX license identifiers to all files which: - Have no license information of any form - Have EXPORT_.*_SYMBOL_GPL inside which was used in the initial scan/conversion to ignore the file These files fall under the project license, GPL v2 only. The resulting SPDX license identifier is: GPL-2.0-only Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-04-24SUNRPC: Allow further customisation of RPC program registrationTrond Myklebust1-31/+54
Add a callback to allow customisation of the rpcbind registration. When clients have the ability to turn on and off version support, we want to allow them to also prevent registration of those versions with the rpc portmapper. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2019-04-24SUNRPC: Clean up generic dispatcher codeTrond Myklebust1-28/+47
Simplify the generic server dispatcher. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2019-04-24SUNRPC: Add a callback to initialise server requestsTrond Myklebust1-37/+76
Add a callback to help initialise server requests before they are processed. This will allow us to clean up the NFS server version support, and to make it container safe. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2019-04-24SUNRPC/nfs: Fix return value for nfs4_callback_compound()Trond Myklebust1-5/+22
RPC server procedures are normally expected to return a __be32 encoded status value of type 'enum rpc_accept_stat', however at least one function wants to return an authentication status of type 'enum rpc_auth_stat' in the case where authentication fails. This patch adds functionality to allow this. Fixes: a4e187d83d88 ("NFS: Don't drop CB requests with invalid principals") Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2019-02-13SUNRPC: Remove rpc_xprt::tsh_sizeChuck Lever1-15/+4
tsh_size was added to accommodate transports that send a pre-amble before each RPC message. However, this assumes the pre-amble is fixed in size, which isn't true for some transports. That makes tsh_size not very generic. Also I'd like to make the estimation of RPC send and receive buffer sizes more precise. tsh_size doesn't currently appear to be accounted for at all by call_allocate. Therefore let's just remove the tsh_size concept, and make the only transports that have a non-zero tsh_size employ a direct approach. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2018-12-28sunrpc: make visible processing error in bc_svc_process()Vasily Averin1-2/+2
Force bc_svc_process() to generate debug message after processing errors Signed-off-by: Vasily Averin <vvs@virtuozzo.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2018-12-28sunrpc: remove unused xpo_prep_reply_hdr callbackVasily Averin1-0/+11
xpo_prep_reply_hdr are not used now. It was defined for tcp transport only, however it cannot be called indirectly, so let's move it to its caller and remove unused callback. Signed-off-by: Vasily Averin <vvs@virtuozzo.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2018-12-28sunrpc: use-after-free in svc_process_common()Vasily Averin1-4/+5
if node have NFSv41+ mounts inside several net namespaces it can lead to use-after-free in svc_process_common() svc_process_common() /* Setup reply header */ rqstp->rq_xprt->xpt_ops->xpo_prep_reply_hdr(rqstp); <<< HERE svc_process_common() can use incorrect rqstp->rq_xprt, its caller function bc_svc_process() takes it from serv->sv_bc_xprt. The problem is that serv is global structure but sv_bc_xprt is assigned per-netnamespace. According to Trond, the whole "let's set up rqstp->rq_xprt for the back channel" is nothing but a giant hack in order to work around the fact that svc_process_common() uses it to find the xpt_ops, and perform a couple of (meaningless for the back channel) tests of xpt_flags. All we really need in svc_process_common() is to be able to run rqstp->rq_xprt->xpt_ops->xpo_prep_reply_hdr() Bruce J Fields points that this xpo_prep_reply_hdr() call is an awfully roundabout way just to do "svc_putnl(resv, 0);" in the tcp case. This patch does not initialiuze rqstp->rq_xprt in bc_svc_process(), now it calls svc_process_common() with rqstp->rq_xprt = NULL. To adjust reply header svc_process_common() just check rqstp->rq_prot and calls svc_tcp_prep_reply_hdr() for tcp case. To handle rqstp->rq_xprt = NULL case in functions called from svc_process_common() patch intruduces net namespace pointer svc_rqst->rq_bc_net and adjust SVC_NET() definition. Some other function was also adopted to properly handle described case. Signed-off-by: Vasily Averin <vvs@virtuozzo.com> Cc: stable@vger.kernel.org Fixes: 23c20ecd4475 ("NFS: callback up - users counting cleanup") Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2018-08-09NFSD: Handle full-length symlinksChuck Lever1-42/+25
I've given up on the idea of zero-copy handling of SYMLINK on the server side. This is because the Linux VFS symlink API requires the symlink pathname to be in a NUL-terminated kmalloc'd buffer. The NUL-termination is going to be problematic (watching out for landing on a page boundary and dealing with a 4096-byte pathname). I don't believe that SYMLINK creation is on a performance path or is requested frequently enough that it will cause noticeable CPU cache pollution due to data copies. There will be two places where a transport callout will be necessary to fill in the rqstp: one will be in the svc_fill_symlink_pathname() helper that is used by NFSv2 and NFSv3, and the other will be in nfsd4_decode_create(). Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2018-08-09NFSD: Refactor the generic write vector fill helperChuck Lever1-7/+4
fill_in_write_vector() is nearly the same logic as svc_fill_write_vector(), but there are a few differences so that the former can handle multiple WRITE payloads in a single COMPOUND. svc_fill_write_vector() can be adjusted so that it can be used in the NFSv4 WRITE code path too. Instead of assuming the pages are coming from rq_args.pages, have the caller pass in the page list. The immediate benefit is a reduction of code duplication. It also prevents the NFSv4 WRITE decoder from passing an empty vector element when the transport has provided the payload in the xdr_buf's page array. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2018-04-03NFSD: Clean up legacy NFS SYMLINK argument XDR decodersChuck Lever1-0/+67
Move common code in NFSD's legacy SYMLINK decoders into a helper. The immediate benefits include: - one fewer data copies on transports that support DDP - consistent error checking across all versions - reduction of code duplication - support for both legal forms of SYMLINK requests on RDMA transports for all versions of NFS (in particular, NFSv2, for completeness) In the long term, this helper is an appropriate spot to perform a per-transport call-out to fill the pathname argument using, say, RDMA Reads. Filling the pathname in the proc function also means that eventually the incoming filehandle can be interpreted so that filesystem- specific memory can be allocated as a sink for the pathname argument, rather than using anonymous pages. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2018-04-03NFSD: Clean up legacy NFS WRITE argument XDR decodersChuck Lever1-0/+42
Move common code in NFSD's legacy NFS WRITE decoders into a helper. The immediate benefit is reduction of code duplication and some nice micro-optimizations (see below). In the long term, this helper can perform a per-transport call-out to fill the rq_vec (say, using RDMA Reads). The legacy WRITE decoders and procs are changed to work like NFSv4, which constructs the rq_vec just before it is about to call vfs_writev. Why? Calling a transport call-out from the proc instead of the XDR decoder means that the incoming FH can be resolved to a particular filesystem and file. This would allow pages from the backing file to be presented to the transport to be filled, rather than presenting anonymous pages and copying or flipping them into the file's page cache later. I also prefer using the pages in rq_arg.pages, instead of pulling the data pages directly out of the rqstp::rq_pages array. This is currently the way the NFSv3 write decoder works, but the other two do not seem to take this approach. Fixing this removes the only reference to rq_pages found in NFSD, eliminating an NFSD assumption about how transports use the pages in rq_pages. Lastly, avoid setting up the first element of rq_vec as a zero- length buffer. This happens with an RDMA transport when a normal Read chunk is present because the data payload is in rq_arg's page list (none of it is in the head buffer). Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
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