kernel/linux.git/include/linux/sunrpc/xdr.h, branch v6.18.43

SUNRPC: Return an error from xdr_buf_to_bvec() on overflow

2026-08-03T09:22:10+00:00

[ Upstream commit 18c1cc69886192e33536498289d26dba6894e3d5 ] xdr_buf_to_bvec() returns a slot count even when the caller's bvec budget is exhausted partway through the xdr_buf. Callers feed that count into iov_iter_bvec() and continue as if the conversion had succeeded, silently sending or writing fewer bytes than the data length declares. For an NFS WRITE the server reports the truncated transfer to the client as full success. The overflow represents an internal invariant violation: a higher layer reserved a bvec budget too small for the xdr_buf it then asked the encoder to convert. That is a server-side fault, not a media I/O failure and not a malformed client argument. Change xdr_buf_to_bvec() to return a signed int and have the overflow label return -ESERVERFAULT. Update the three callers to detect the negative return and fail the request: nfsd_vfs_write() folds the error into host_err, which nfserrno() translates to nfserr_serverfault for the WRITE reply; svc_udp_sendto() and svc_tcp_sendmsg() propagate the error out of the send path. Reported-by: Chris Mason Fixes: 2eb2b9358181 ("SUNRPC: Convert svc_tcp_sendmsg to use bio_vecs directly") Cc: stable@vger.kernel.org Reviewed-by: Jeff Layton Signed-off-by: Chuck Lever Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

SUNRPC: Add helpers to convert xdr_buf byte ranges to scatterlists

2026-08-03T09:22:10+00:00

[ Upstream commit e9be933959b581effd426f93b86654f5fbf0c574 ] The crypto/krb5 library accepts data in scatterlist form, but the GSS-API layer presents RPC payloads as struct xdr_buf. Bridge that gap with a pair of helper functions: xdr_buf_to_sg() - populate a caller-supplied scatterlist array from a byte range xdr_buf_to_sg_alloc() - populate a caller-supplied inline scatterlist, chaining to a heap- allocated overflow for large payloads The inline array (typically stack-allocated at eight entries) covers the common case of small RPCs with no heap allocation on the encrypt/decrypt path. Only buffers spanning many pages incur a kmalloc for the chained extension. The segment-walking logic follows the same head, page array, tail traversal as xdr_process_buf(), but populates a scatterlist directly rather than invoking a per-segment callback. sg_next() traversal makes the walker safe for chained scatterlists. Once subsequent patches reroute all per-message crypto operations through crypto/krb5, xdr_process_buf() loses its last callers and is removed. Assisted-by: Claude:claude-opus-4-6 Reviewed-by: Jeff Layton Acked-by: Anna Schumaker Signed-off-by: Chuck Lever Stable-dep-of: 18c1cc698861 ("SUNRPC: Return an error from xdr_buf_to_bvec() on overflow") Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

Merge tag 'nfsd-6.18' of git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux

2025-10-06T20:22:21+00:00

Pull nfsd updates from Chuck Lever: "Mike Snitzer has prototyped a mechanism for disabling I/O caching in NFSD. This is introduced in v6.18 as an experimental feature. This enables scaling NFSD in /both/ directions: - NFS service can be supported on systems with small memory footprints, such as low-cost cloud instances - Large NFS workloads will be less likely to force the eviction of server-local activity, helping it avoid thrashing Jeff Layton contributed a number of fixes to the new attribute delegation implementation (based on a pending Internet RFC) that we hope will make attribute delegation reliable enough to enable by default, as it is on the Linux NFS client. The remaining patches in this pull request are clean-ups and minor optimizations. Many thanks to the contributors, reviewers, testers, and bug reporters who participated during the v6.18 NFSD development cycle" * tag 'nfsd-6.18' of git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux: (42 commits) nfsd: discard nfserr_dropit SUNRPC: Make RPCSEC_GSS_KRB5 select CRYPTO instead of depending on it NFSD: Add io_cache_{read,write} controls to debugfs NFSD: Do the grace period check in ->proc_layoutget nfsd: delete unnecessary NULL check in __fh_verify() NFSD: Allow layoutcommit during grace period NFSD: Disallow layoutget during grace period sunrpc: fix "occurence"->"occurrence" nfsd: Don't force CRYPTO_LIB_SHA256 to be built-in nfsd: nfserr_jukebox in nlm_fopen should lead to a retry NFSD: Reduce DRC bucket size NFSD: Delay adding new entries to LRU SUNRPC: Move the svc_rpcb_cleanup() call sites NFS: Remove rpcbind cleanup for NFSv4.0 callback nfsd: unregister with rpcbind when deleting a transport NFSD: Drop redundant conversion to bool sunrpc: eliminate return pointer in svc_tcp_sendmsg() sunrpc: fix pr_notice in svc_tcp_sendto() to show correct length nfsd: decouple the xprtsec policy check from check_nfsd_access() NFSD: Fix destination buffer size in nfsd4_ssc_setup_dul() ...

SUNRPC: Update gssx_accept_sec_context() to use xdr_set_scratch_folio()

2025-09-23T17:29:50+00:00

This was the last caller of xdr_set_scratch_page(), so I remove this function while I'm at it. Signed-off-by: Anna Schumaker

SUNRPC: Introduce xdr_set_scratch_folio()

2025-09-23T17:29:50+00:00

This will replace xdr_set_scratch_page() when we switch pages to folios. Signed-off-by: Anna Schumaker

sunrpc: Change ret code of xdr_stream_decode_opaque_fixed

2025-09-21T23:24:50+00:00

Since the opaque is fixed in size, the caller already knows how many bytes were decoded, on success. Thus, xdr_stream_decode_opaque_fixed() doesn't need to return that value. And, xdr_stream_decode_u32 and _u64 both return zero on success. This patch simplifies the caller's error checking to avoid potential integer promotion issues. Suggested-by: Dan Carpenter Signed-off-by: Sergey Bashirov Signed-off-by: Chuck Lever

Merge tag 'nfs-for-6.17-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs

2025-08-09T04:20:44+00:00

Pull NFS client updates from Trond Myklebust: "Highlights include: Stable fixes: - don't inherit NFS filesystem capabilities when crossing from one filesystem to another Bugfixes: - NFS wakeup of __nfs_lookup_revalidate() needs memory barriers - NFS improve bounds checking in nfs_fh_to_dentry() - NFS Fix allocation errors when writing to a NFS file backed loopback device - NFSv4: More listxattr fixes - SUNRPC: fix client handling of TLS alerts - pNFS block/scsi layout fix for an uninitialised pointer dereference - pNFS block/scsi layout fixes for the extent encoding, stripe mapping, and disk offset overflows - pNFS layoutcommit work around for RPC size limitations - pNFS/flexfiles avoid looping when handling fatal errors after layoutget - localio: fix various race conditions Features and cleanups: - Add NFSv4 support for retrieving the btime - NFS: Allow folio migration for the case of mode == MIGRATE_SYNC - NFS: Support using a kernel keyring to store TLS certificates - NFSv4: Speed up delegation lookup using a hash table - Assorted cleanups to remove unused variables and struct fields - Assorted new tracepoints to improve debugging" * tag 'nfs-for-6.17-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs: (44 commits) NFS/localio: nfs_uuid_put() fix the wake up after unlinking the file NFS/localio: nfs_uuid_put() fix races with nfs_open/close_local_fh() NFS/localio: nfs_close_local_fh() fix check for file closed NFSv4: Remove duplicate lookups, capability probes and fsinfo calls NFS: Fix the setting of capabilities when automounting a new filesystem sunrpc: fix client side handling of tls alerts nfs/localio: use read_seqbegin() rather than read_seqbegin_or_lock() NFS: Fixup allocation flags for nfsiod's __GFP_NORETRY NFSv4.2: another fix for listxattr NFS: Fix filehandle bounds checking in nfs_fh_to_dentry() SUNRPC: Silence warnings about parameters not being described NFS: Clean up pnfs_put_layout_hdr()/pnfs_destroy_layout_final() NFS: Fix wakeup of __nfs_lookup_revalidate() in unblock_revalidate() NFS: use a hash table for delegation lookup NFS: track active delegations per-server NFS: move the delegation_watermark module parameter NFS: cleanup nfs_inode_reclaim_delegation NFS: cleanup error handling in nfs4_server_common_setup pNFS/flexfiles: don't attempt pnfs on fatal DS errors NFS: drop __exit from nfs_exit_keyring ...

SUNRPC: Remove unused xdr functions

2025-07-14T22:20:28+00:00

Remove a bunch of unused xdr_*decode* functions: The last use of xdr_decode_netobj() was removed in 2021 by: commit 7cf96b6d0104 ("lockd: Update the NLMv4 SHARE arguments decoder to use struct xdr_stream") The last use of xdr_decode_string_inplace() was removed in 2021 by: commit 3049e974a7c7 ("lockd: Update the NLMv4 FREE_ALL arguments decoder to use struct xdr_stream") The last use of xdr_stream_decode_opaque() was removed in 2024 by: commit fed8a17c61ff ("xdrgen: typedefs should use the built-in string and opaque functions") The functions xdr_stream_decode_string() and xdr_stream_decode_opaque_dup() were both added in 2018 by the commit 0e779aa70308 ("SUNRPC: Add helpers for decoding opaque and string types") but never used. Remove them. Signed-off-by: Dr. David Alan Gilbert Link: https://lore.kernel.org/r/20250712233006.403226-1-linux@treblig.org Signed-off-by: Trond Myklebust

sunrpc: fix handling of unknown auth status codes

2025-07-14T16:46:47+00:00

In the case of an unknown error code from svc_authenticate or pg_authenticate, return AUTH_ERROR with a status of AUTH_FAILED. Also add the other auth_stat value from RFC 5531, and document all the status codes. Signed-off-by: Jeff Layton Signed-off-by: Chuck Lever

sunrpc: simplify xdr_init_encode_pages

2025-07-14T16:46:37+00:00

The rqst argument to xdr_init_encode_pages is set to NULL by all callers, and pages is always set to buf->pages. Remove the two arguments and hardcode the assignments. Signed-off-by: Christoph Hellwig Reviewed-by: Jeff Layton Signed-off-by: Chuck Lever