kernel/include/linux/sunrpc/svc.h, branch linux-5.11.y

SUNRPC: Prepare for xdr_stream-style decoding on the server-side

2020-11-30T19:46:35Z

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

SUNRPC: Rename svc_encode_read_payload()

2020-11-30T18:00:21Z

Clean up: "result payload" is a less confusing name for these payloads. "READ payload" reflects only the NFS usage. Signed-off-by: Chuck Lever

Merge branch 'nfsd-5.8' of git://linux-nfs.org/~cel/cel-2.6 into for-5.8-incoming

2020-05-21T14:58:15Z

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

SUNRPC: Refactor svc_recvfrom()

2020-05-20T21:30:12Z

This function is not currently "generic" so remove the documenting comment and rename it appropriately. Its internals are converted to use bio_vecs for reading from the transport socket. In existing typical sunrpc uses of bio_vecs, the bio_vec array is allocated dynamically. Here, instead, an array of bio_vecs is added to svc_rqst. The lifetime of this array can be greater than one call to xpo_recvfrom(): - Multiple calls to xpo_recvfrom() might be needed to read an RPC message completely. - At some later point, rq_arg.bvecs will point to this array and it will carry the received message into svc_process(). I also expect that a future optimization will remove either the rq_vec or rq_pages array in favor of rq_bvec, thus conserving the size of struct svc_rqst. Signed-off-by: Chuck Lever

nfsd: clients don't need to break their own delegations

2020-05-09T01:23:10Z

We currently revoke read delegations on any write open or any operation that modifies file data or metadata (including rename, link, and unlink). But if the delegation in question is the only read delegation and is held by the client performing the operation, that's not really necessary. It's not always possible to prevent this in the NFSv4.0 case, because there's not always a way to determine which client an NFSv4.0 delegation came from. (In theory we could try to guess this from the transport layer, e.g., by assuming all traffic on a given TCP connection comes from the same client. But that's not really correct.) In the NFSv4.1 case the session layer always tells us the client. This patch should remove such self-conflicts in all cases where we can reliably determine the client from the compound. To do that we need to track "who" is performing a given (possibly lease-breaking) file operation. We're doing that by storing the information in the svc_rqst and using kthread_data() to map the current task back to a svc_rqst. Signed-off-by: J. Bruce Fields

nfsd: Fix NFSv4 READ on RDMA when using readv

2020-03-16T16:04:31Z

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

sunrpc: Replace zero-length array with flexible-array member

2020-03-16T16:04:31Z

The current codebase makes use of the zero-length array language extension to the C90 standard, but the preferred mechanism to declare variable-length types such as these ones is a flexible array member[1][2], introduced in C99: struct foo { int stuff; struct boo array[]; }; By making use of the mechanism above, we will get a compiler warning in case the flexible array does not occur last in the structure, which will help us prevent some kind of undefined behavior bugs from being inadvertently introduced[3] to the codebase from now on. Also, notice that, dynamic memory allocations won't be affected by this change: "Flexible array members have incomplete type, and so the sizeof operator may not be applied. As a quirk of the original implementation of zero-length arrays, sizeof evaluates to zero."[1] This issue was found with the help of Coccinelle. [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html [2] https://github.com/KSPP/linux/issues/21 [3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour") Signed-off-by: Gustavo A. R. Silva Signed-off-by: J. Bruce Fields Signed-off-by: Chuck Lever

SUNRPC: Allow further customisation of RPC program registration

2019-04-24T13:46:35Z

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 Signed-off-by: J. Bruce Fields

SUNRPC: Add a callback to initialise server requests

2019-04-24T13:46:34Z

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 Signed-off-by: J. Bruce Fields

SUNRPC/nfs: Fix return value for nfs4_callback_compound()

2019-04-24T13:46:34Z

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 Signed-off-by: J. Bruce Fields