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2026-10-11NFSD: Use xdrgen XDR functions for NFSv2 READDIR resultsChuck Lever
READDIR is the last NFSv2 procedure whose reply is still produced by a hand-written encoder. Its entry list is the value-follows form of RFC 1094's "entry *entries" -- each entry prefixed by TRUE, the sequence closed by FALSE -- streamed straight from the directory as it is read rather than from a materialized array. The generated encoder could not drive that: the union encoder writes the reply status word before the entry list, yet a streamed read does not learn the status until the directory has been read, and the aggregate loop was bounded by a count the begin hook had to supply up front. The preceding patches remove both obstacles. The optional-data aggregate encoder now pulls entries until the hook signals end, so no count is needed, and the streaming directory reader yields one entry at a time during encode. Mark readdirok's entry list as an aggregate and regenerate; the struct definitions stay the verbatim RFC 1094 types, and the lone "pragma aggregate readdirok entries" selects the hook-driven codec. Split the read across the two phases so the generated encoder owns the framing. nfsd_proc_readdir() opens the directory, where an open error becomes the reply status the union encoder then writes, and the encode hooks stream the entries: each pull reserves a placeholder cookie and back-patches the preceding entry's cookie once the following entry's resume offset is known; the end hook back-patches the final cookie and reports eof. nfssvc_release_readdirres() closes the reader and releases the file handle. The decode hooks are stubs -- a server never decodes a READDIR result -- present only to satisfy the generated decoder's linkage. Retire struct nfsd_readdirres for an embedded struct readdirres so the RPC dispatch layer can cast the response to its xdrgen type. The directory's svc_fh moves into that wrapper and struct readdirargs_wrapper goes away. svc_process() zeroes the result buffer before decode but leaves the argument buffer as the previous request left it, and ->pc_release runs even when decoding fails. A file handle kept in the argument wrapper would reach fh_put() on that path uninitialized. The generated encoder reserves reply space through the xdr_stream, which does not advance rq_next_page as it moves onto the next page. svcrdma retains only the pages below rq_next_page across Send completion, so the end hook sets rq_next_page past the last page the reply uses, as nfsd4_encode_operation() does. A host error during the streamed read cannot retract entries already on the wire, so it ends the list as a truncated, non-eof reply rather than an error status; an error opening the directory is still reported as the reply status. The bytes on the wire are otherwise unchanged. Acked-by: Jeff Layton <jlayton@kernel.org> Link: https://patch.msgid.link/20260916162859.2051-30-cel@kernel.org Signed-off-by: Chuck Lever <cel@kernel.org>
2026-10-11NFSD: Use xdrgen XDR functions for NFSv2 SYMLINK procedureChuck Lever
A SYMLINK request's target pathname can extend from the head of the receive buffer into its page data; the decoder reassembles it from a head segment and a page via svc_fill_symlink_pathname(). Represent the pathname in place rather than materializing it inline: the "pages" directive expresses it as a struct xdr_buf and decodes it with svcxdr_decode_opaque_payload(), which subsegments the source stream instead of pulling the string inline through the bounded xdr scratch buffer. Annotate the to member of symlinkargs with "pragma pages" and replace the NFSPROC_SYMLINK entry in nfsd_procedures2 with the generated nfs_svc_decode_symlinkargs and nfs_svc_encode_nfsstat. A wrapper structure bridges the generated symlinkargs type and the svc_fh and iattr representations the NFSD VFS layer still uses. nfsd_proc_symlink() copies the pathname out of the xdr_buf with read_bytes_from_xdr_buf(), so a target that lands in the receive buffer's tail, or straddles its pages and tail, is handled the same way as one in the head. The pc_argzero field is now set to zero for the NFSv2 SYMLINK procedure. The generated decoder initializes every argument in the argp->xdrgen field, making the early defensive memset unnecessary. The hand-coded nfsd_proc_symlink() accepts a target of any length from the decoder and answers one longer than NFS_MAXPATHLEN with NFSERR_NAMETOOLONG. The generated decoder enforces the path typedef's bound itself, so such a request now fails decoding and nfsd_dispatch() returns RPC GARBAGE_ARGS instead. The Linux NFS client sends targets up to PAGE_SIZE on an NFSv2 mount, and in that case it reports EIO to the application rather than ENAMETOOLONG. nfssvc_decode_symlinkargs() no longer has any callers, so it is removed. Acked-by: Jeff Layton <jlayton@kernel.org> Link: https://patch.msgid.link/20260916162859.2051-23-cel@kernel.org Signed-off-by: Chuck Lever <cel@kernel.org>
2026-10-11NFSD: Use xdrgen XDR functions for NFSv2 WRITE procedureChuck Lever
The NFSv2 WRITE argument decoder could not be generated because the write payload must be directed into the server's page cache and decoded in place; a materializing decoder would copy every write. The "pages" directive now expresses this: it represents the payload as a struct xdr_buf and decodes it with svcxdr_decode_opaque_payload(), which subsegments the source stream in place rather than copying it. Annotate the data member of writeargs with "pragma pages" and replace the NFSPROC_WRITE entry in nfsd_procedures2 with the generated nfs_svc_decode_writeargs and nfs_svc_encode_attrstat. A wrapper structure bridges the generated writeargs type and the svc_fh the NFSD VFS layer still uses; the result reuses the attrstat wrapper from the GETATTR conversion. The pc_argzero field is now set to zero for the NFSv2 WRITE procedure. The generated decoder initializes every argument in the argp->xdrgen field, making the early defensive memset unnecessary. This refactor replaces the use of svcxdr_encode_fattr(), so the reference to the file handle can be released directly by nfsd_proc_write(). A separate ->pc_release callback is thus no longer needed. This makes it straightforward to confirm that the file handle is properly released during every error flow. Acked-by: Jeff Layton <jlayton@kernel.org> Link: https://patch.msgid.link/20260916162859.2051-17-cel@kernel.org Signed-off-by: Chuck Lever <cel@kernel.org>
2026-10-11NFSD: Use xdrgen XDR functions for NFSv2 READ procedureChuck Lever
Replace the hand-written NFSv2 READ codec pair with the xdrgen-generated functions. The NFSPROC_READ entry in the nfsd_procedures2 array now dispatches nfs_svc_decode_readargs and nfs_svc_encode_readres. A wrapper structure bridges the generated xdrgen readargs type and the legacy svc_fh representation the NFSD VFS layer still uses. The file's data does not reside at the data pointer of the readresok data member: nfsd_read() deposits it directly in the pages of the Reply buffer, so the generic encoder that copies an opaque from the member's data pointer cannot encode it. Mark the member with the "pragma pages" directive so the generated encoder calls svcxdr_encode_opaque_payload(), which encodes the length prefix and inserts the payload pages into the stream by reference. The page anchor that the result structure carried duplicated rq_res.pages -- svc_process() points rq_res.pages at the first Reply page before dispatch, and the readargs decoder consumes no pages -- so the helper locates the payload through the Reply buffer itself, and the wrapper collapses to the generated readres type. The pc_argzero field is now set to zero for the NFSv2 READ procedure. The xdrgen decoders are trusted to initialize all arguments in the argp->xdrgen field, making the early defensive memset unnecessary. The remaining argp fields are cleared as needed. Because the generated encoder no longer needs the svc_fh at encode time, nfsd_proc_read() releases the file handle directly and no separate ->pc_release callback is needed. This makes it straightforward to confirm that the file handle is properly released during every error flow. Acked-by: Jeff Layton <jlayton@kernel.org> Link: https://patch.msgid.link/20260916162859.2051-15-cel@kernel.org Signed-off-by: Chuck Lever <cel@kernel.org>
2026-10-11NFSD: Use xdrgen XDR functions for NFSv2 READLINK procedureChuck Lever
Replace the hand-written NFSv2 READLINK codec pair with the xdrgen-generated functions. The NFSPROC_READLINK entry in the nfsd_procedures2 array now dispatches nfs_svc_decode_fhandle and nfs_svc_encode_readlinkres. A wrapper structure bridges the generated xdrgen fhandle type and the legacy svc_fh representation the NFSD VFS layer still uses. The link target does not reside at the data pointer of the readlinkres union arm: nfsd_readlink() deposits it directly in a page of the Reply buffer, so the generic encoder that copies an opaque from the member's data pointer cannot encode it. Mark the arm with the "pragma pages" directive so the generated encoder calls svcxdr_encode_opaque_payload(), which encodes the length prefix and inserts the payload page into the stream by reference. The page anchor that the result structure carried duplicated rq_res.pages -- svc_process() points rq_res.pages at the first Reply page before dispatch, and the fhandle argument decoder consumes no pages -- so the helper locates the payload through the Reply buffer itself, and the wrapper collapses to the generated readlinkres type. The pc_argzero field is now set to zero for the NFSv2 READLINK procedure. The xdrgen decoders are trusted to initialize all arguments in the argp->xdrgen field, making the early defensive memset unnecessary. The remaining argp fields are cleared as needed. Acked-by: Jeff Layton <jlayton@kernel.org> Link: https://patch.msgid.link/20260916162859.2051-14-cel@kernel.org Signed-off-by: Chuck Lever <cel@kernel.org>
2026-10-11NFSD: Use xdrgen XDR functions for NFSv2 GETATTR procedureChuck Lever
Replace the NFSPROC_GETATTR entry in the nfsd_procedures2 array with an entry that dispatches the xdrgen-generated nfs_svc_decode_fhandle and nfs_svc_encode_attrstat. Wrapper structures bridge the generated xdrgen types and the legacy svc_fh and kstat representations the NFSD VFS layer still uses. A few helper functions are introduced which will be used here and in subsequent patches. The pc_argzero field is now set to zero for the NFSv2 GETATTR procedure. The xdrgen decoders are trusted to initialize all arguments in the argp->xdrgen field, making the early defensive memset unnecessary. The remaining argp fields are cleared as needed. This refactor replaces the use of svcxdr_encode_fattr(), so the reference to the file handle can be released directly by nfsd_proc_getattr(). A separate ->pc_release callback is thus no longer needed. This makes it straightforward to confirm that the file handle is properly released during every error flow. The new nfsd_mode_to_ftype() utility no longer maps socket and FIFO devices to non-standard values: NFSOCK=6 which is outside the ftype enum, and NFCHR for FIFOs which is semantically wrong. The Linux NFS client implementation does not seem to use or depend on these non-standard values. The new utility function returns NFNON for both, which is the RFC-compliant behavior. Acked-by: Jeff Layton <jlayton@kernel.org> Link: https://patch.msgid.link/20260916162859.2051-10-cel@kernel.org Signed-off-by: Chuck Lever <cel@kernel.org>
2026-10-11NFSD: Add infrastructure for generating NFSv2 XDR encoders and decodersChuck Lever
NFSD's NFSv2 XDR codecs are hand-maintained; they are being converted to xdrgen-generated code one RPC procedure at a time. The first step is to generate and commit the xdrgen C code based on nfs2.x. The generated code can be refreshed any time nfs2.x is modified by running "(cd fs/nfsd && make xdrgen)". Acked-by: Jeff Layton <jlayton@kernel.org> Link: https://patch.msgid.link/20260916162859.2051-4-cel@kernel.org Signed-off-by: Chuck Lever <cel@kernel.org>
2026-10-11Documentation: Add the RPC language description of NFSv2Chuck Lever
In order to generate source code to encode and decode NFSv2 protocol elements, include a copy of the RPC language description of NFSv2 for xdrgen to process. The language description is an amalgam of RFC 1094 and the Open Group's XNFS specification: https://pubs.opengroup.org/onlinepubs/9629799/chap7.htm The goals of replacing hand-written XDR functions with ones that are tool-generated are to improve memory safety and make XDR encoding and decoding less brittle to maintain. Parts of the NFSv4 protocol are still being extended actively. Tool-generated XDR code reduces the time it takes to get a working implementation of new protocol elements. The xdrgen utility derives both the type definitions and the encode/decode functions directly from protocol specifications, using names and symbols familiar to anyone who knows those specs. Unlike hand-written code that can inadvertently diverge from the specification, xdrgen guarantees that the generated code matches the specification exactly. We would eventually like xdrgen to generate Rust code as well, making the conversion of the kernel's NFS stacks to use Rust just a little easier for us. Acked-by: Jeff Layton <jlayton@kernel.org> Link: https://patch.msgid.link/20260916162859.2051-2-cel@kernel.org Signed-off-by: Chuck Lever <cel@kernel.org>
2026-08-10nfsd: add support to CB_NOTIFY for dir attribute changesJeff Layton
If the client requested dir attribute change notifications, send those alongside any set of add/remove/rename events. Note that the server will still recall the delegation on a SETATTR, so these are only sent for changes to child dirents. Signed-off-by: Jeff Layton <jlayton@kernel.org> [ cel: folded "nfsd: fix CB_NOTIFY workqueue loop when queue overflows" ] [ cel: folded "nfsd: recall deleg if a requested dir attr change can't be encoded" ] Link: https://patch.msgid.link/20260616-dir-deleg-v7-20-6cbc7eac0ade@kernel.org Signed-off-by: Chuck Lever <cel@kernel.org>
2026-08-10nfsd: add notification handlers for dir eventsJeff Layton
Add the necessary parts to accept a fsnotify callback for directory change event and create a CB_NOTIFY request for it. When a dir nfsd_file is created set a handle_event callback to handle the notification. Use that to allocate a nfsd_notify_event object and then hand off a reference to each delegation's CB_NOTIFY. If anything fails along the way, recall any affected delegations. Signed-off-by: Jeff Layton <jlayton@kernel.org> Link: https://patch.msgid.link/20260616-dir-deleg-v7-10-6cbc7eac0ade@kernel.org Signed-off-by: Chuck Lever <cel@kernel.org>
2026-08-10nfsd: add callback encoding and decoding linkages for CB_NOTIFYJeff Layton
Add routines for encoding and decoding CB_NOTIFY messages. These call into the code generated by xdrgen to do the actual encoding and decoding. For now, the encoder is a stub. Later patches will flesh out the payload encoding. Signed-off-by: Jeff Layton <jlayton@kernel.org> Link: https://patch.msgid.link/20260616-dir-deleg-v7-7-6cbc7eac0ade@kernel.org Signed-off-by: Chuck Lever <cel@kernel.org>
2026-08-10nfs_common: add new NOTIFY4_* flags proposed in RFC8881bisJeff Layton
RFC8881bis adds some new flags to GET_DIR_DELEGATION that later patches will consume. In particular, Linux nfsd can't easily provide info about directory cookies and ordering. The new flags allow it to omit that information. There is some risk here -- RFC8881bis is still a working group document, and has been for years. The changes to directory delegations have been stable for the last year or so however, so the hope is that those parts won't change (much). Signed-off-by: Jeff Layton <jlayton@kernel.org> Link: https://patch.msgid.link/20260616-dir-deleg-v7-3-6cbc7eac0ade@kernel.org Signed-off-by: Chuck Lever <cel@kernel.org>
2026-08-10nfsd: add protocol support for CB_NOTIFYJeff Layton
Add the necessary bits to nfs4_1.x and remove the duplicate definitions from nfs4.h and the uapi nfs4 header. Regenerate the xdr files. Note that regenerating these files caused conflicts with the definitions of NFS4_VERIFIER_SIZE and NFS4_FHSIZE in include/uapi/linux/nfs4.h. These constants are defined by the RFC, and are not part of the kernel API. They have been removed. Userspace consumers who require those constants should plan to get them from more authoritative sources. The nfsstat4 enum defined in the .x is fed to the xdrgen-generated wire encoder and decoder, which treat every enumerated value as legal on the wire. Do not carry the NFS4ERR_FIRST_FREE sentinel (which is not a protocol error code) into the .x; keeping it would make 10097 a value that could leak onto the wire. Instead base nfsd's internal error codes (NFSERR_EOF and friends) at an impossible nfsstat4 value, as lockd does for its nlm__int__* status codes. Signed-off-by: Jeff Layton <jlayton@kernel.org> Link: https://patch.msgid.link/20260616-dir-deleg-v7-2-6cbc7eac0ade@kernel.org Signed-off-by: Chuck Lever <cel@kernel.org>
2026-06-09Documentation: Add the RPC language description of NLM version 3Chuck Lever
In order to generate source code to encode and decode NLMv3 protocol elements, include a copy of the RPC language description of NLMv3 for xdrgen to process. The language description is derived from the Open Group's XNFS specification: https://pubs.opengroup.org/onlinepubs/9629799/chap10.htm#tagcjh_11_03 The C code committed here was generated from the new nlm3.x file using tools/net/sunrpc/xdrgen/xdrgen. The goals of replacing hand-written XDR functions with ones that are tool-generated are to improve memory safety and make XDR encoding and decoding less brittle to maintain. Parts of the NFSv4 protocol are still being extended actively. Tool-generated XDR code reduces the time it takes to get a working implementation of new protocol elements. The xdrgen utility derives both the type definitions and the encode/decode functions directly from protocol specifications, using names and symbols familiar to anyone who knows those specs. Unlike hand-written code that can inadvertently diverge from the specification, xdrgen guarantees that the generated code matches the specification exactly. We would eventually like xdrgen to generate Rust code as well, making the conversion of the kernel's NFS stacks to use Rust just a little easier for us. Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2026-03-29Documentation: Add the RPC language description of NLM version 4Chuck Lever
In order to generate source code to encode and decode NLMv4 protocol elements, include a copy of the RPC language description of NLMv4 for xdrgen to process. The language description is an amalgam of RFC 1813 and the Open Group's XNFS specification: https://pubs.opengroup.org/onlinepubs/9629799/chap10.htm The C code committed here was generated from the new nlm4.x file using tools/net/sunrpc/xdrgen/xdrgen. The goals of replacing hand-written XDR functions with ones that are tool-generated are to improve memory safety and make XDR encoding and decoding less brittle to maintain. The xdrgen utility derives both the type definitions and the encode/decode functions directly from protocol specifications, using names and symbols familiar to anyone who knows those specs. Unlike hand-written code that can inadvertently diverge from the specification, xdrgen guarantees that the generated code matches the specification exactly. We would eventually like xdrgen to generate Rust code as well, making the conversion of the kernel's NFS stacks to use Rust just a little easier for us. Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2026-01-29Add RPC language definition of NFSv4 POSIX ACL extensionChuck Lever
The language definition was extracted from the new draft-ietf-nfsv4-posix-acls specification. This ensures good constant and type name alignment between the spec and the Linux kernel source code, and brings in some basic XDR utilities for handling NFSv4 POSIX draft ACLs. Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2025-01-21nfsd: rename NFS4_SHARE_WANT_* constants to OPEN4_SHARE_ACCESS_WANT_*Jeff Layton
Add the OPEN4_SHARE_ACCESS_WANT constants from the nfs4.1 and delstid draft into the nfs4_1.x file, and regenerate the headers and source files. Do a mass renaming of NFS4_SHARE_WANT_* to OPEN4_SHARE_ACCESS_WANT_* in the nfsd directory. Signed-off-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2025-01-21nfsd: switch to autogenerated definitions for open_delegation_type4Jeff Layton
Rename the enum with the same name in include/linux/nfs4.h, add the proper enum to nfs4_1.x and regenerate the headers and source files. Do a mass rename of all NFS4_OPEN_DELEGATE_* to OPEN_DELEGATE_* in the nfsd directory. Signed-off-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2025-01-21nfs_common: make include/linux/nfs4.h include generated nfs4_1.hJeff Layton
In the long run, the NFS development community intends to autogenerate a lot of the XDR handling code. Both the NFS client and server include "include/linux/nfs4.hi". That file was hand-rolled, and some of the symbols in it conflict with the autogenerated symbols. Add a small nfs4_1.x to Documentation that currently just has the necessary definitions for the delstid draft, and generate the relevant header and source files. Make include/linux/nfs4.h include the generated include/linux/sunrpc/xdrgen/nfs4_1.h and remove the conflicting definitions from it and nfs_xdr.h. Signed-off-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>