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2026-01-14docs: exportfs: Use source code struct documentationAndré Almeida
Instead of duplicating struct export_operations documentation in both ReST file and in the C source code, just use the kernel-doc in the docs. While here, make the sentence preceding the paragraph less redundant. Signed-off-by: André Almeida <andrealmeid@igalia.com> Link: https://patch.msgid.link/20260112-tonyk-fs_uuid-v1-4-acc1889de772@igalia.com Reviewed-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-12-03NFSD: nfsd-io-modes: Separate listsBagas Sanjaya
Sphinx reports htmldocs indentation warnings: Documentation/filesystems/nfs/nfsd-io-modes.rst:58: ERROR: Unexpected indentation. [docutils] Documentation/filesystems/nfs/nfsd-io-modes.rst:59: WARNING: Block quote ends without a blank line; unexpected unindent. [docutils] These caused the lists to be shown as long running paragraphs merged with their previous paragraphs. Fix these by separating the lists with a blank line. Fixes: fa8d4e6784d1b6 ("NFSD: add Documentation/filesystems/nfs/nfsd-io-modes.rst") Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Closes: https://lore.kernel.org/linux-next/20251202152506.7a2d2d41@canb.auug.org.au/ Signed-off-by: Bagas Sanjaya <bagasdotme@gmail.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> Reviewed-by: Randy Dunlap <rdunlap@infradead.org> Tested-by: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2025-12-03NFSD: nfsd-io-modes: Wrap shell snippets in literal code blocksBagas Sanjaya
Sphinx reports htmldocs indentation warnings: Documentation/filesystems/nfs/nfsd-io-modes.rst:29: ERROR: Unexpected indentation. [docutils] Documentation/filesystems/nfs/nfsd-io-modes.rst:34: ERROR: Unexpected indentation. [docutils] Fix these by wrapping shell snippets in literal code blocks. Fixes: fa8d4e6784d1b6 ("NFSD: add Documentation/filesystems/nfs/nfsd-io-modes.rst") Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Closes: https://lore.kernel.org/linux-next/20251202152506.7a2d2d41@canb.auug.org.au/ Signed-off-by: Bagas Sanjaya <bagasdotme@gmail.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> Reviewed-by: Randy Dunlap <rdunlap@infradead.org> Tested-by: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2025-12-03NFSD: Add toctree entry for NFSD IO modes docsBagas Sanjaya
Commit fa8d4e6784d1b6 ("NFSD: add Documentation/filesystems/nfs/nfsd-io-modes.rst") adds documentation for NFSD I/O modes, but it forgets to add toctree entry for it. Hence, Sphinx reports: Documentation/filesystems/nfs/nfsd-io-modes.rst: WARNING: document isn't included in any toctree [toc.not_included] Add the entry. Fixes: fa8d4e6784d1b6 ("NFSD: add Documentation/filesystems/nfs/nfsd-io-modes.rst") Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Closes: https://lore.kernel.org/linux-next/20251202152506.7a2d2d41@canb.auug.org.au/ Signed-off-by: Bagas Sanjaya <bagasdotme@gmail.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> Reviewed-by: Randy Dunlap <rdunlap@infradead.org> Tested-by: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2025-12-01NFSD: add Documentation/filesystems/nfs/nfsd-io-modes.rstMike Snitzer
This document details the NFSD IO modes that are configurable using NFSD's experimental debugfs interfaces: /sys/kernel/debug/nfsd/io_cache_read /sys/kernel/debug/nfsd/io_cache_write This document will evolve as NFSD's interfaces do (e.g. if/when NFSD's debugfs interfaces are replaced with per-export controls). Future updates will provide more specific guidance and howto information to help others use and evaluate NFSD's IO modes: BUFFERED, DONTCACHE and DIRECT. Signed-off-by: Mike Snitzer <snitzer@kernel.org> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2025-11-17NFS: nfsd-maintainer-entry-profile: Inline function name prefixesBagas Sanjaya
Sphinx reports htmldocs warnings: Documentation/filesystems/nfs/nfsd-maintainer-entry-profile.rst:185: ERROR: Unknown target name: "nfsd". [docutils] Documentation/filesystems/nfs/nfsd-maintainer-entry-profile.rst:188: ERROR: Unknown target name: "nfsdn". [docutils] Documentation/filesystems/nfs/nfsd-maintainer-entry-profile.rst:192: ERROR: Unknown target name: "nfsd4m". [docutils] These are due to Sphinx confusing function name prefixes for external link syntax. Fix the warnings by inlining the prefixes. Fixes: 3a1ce35030e1e0 ("NFSD: Add a subsystem policy document") Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Closes: https://lore.kernel.org/linux-next/20251117174218.29365f30@canb.auug.org.au/ Signed-off-by: Bagas Sanjaya <bagasdotme@gmail.com> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2025-11-16NFSD: Add a subsystem policy documentChuck Lever
Steer contributors to NFSD's patchworks instance, list our patch submission preferences, and more. The new document is based on the existing netdev and xfs subsystem policy documents. This is an attempt to add transparency to the process of accepting contributions to NFSD and getting them merged upstream. Suggested-by: "Darrick J. Wong" <djwong@kernel.org> Cc: Luis Chamberlain <mcgrof@kernel.org> Cc: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: NeilBrown <neil@brown.name> [ cel: Hand-edits to address review comments ] Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2025-03-10nfsd: disallow file locking and delegations for NFSv4 reexportMike Snitzer
We do not and cannot support file locking with NFS reexport over NFSv4.x for the same reason we don't do it for NFSv3: NFS reexport server reboot cannot allow clients to recover locks because the source NFS server has not rebooted, and so it is not in grace. Since the source NFS server is not in grace, it cannot offer any guarantees that the file won't have been changed between the locks getting lost and any attempt to recover/reclaim them. The same applies to delegations and any associated locks, so disallow them too. Clients are no longer allowed to get file locks or delegations from a reexport server, any attempts will fail with operation not supported. Update the "Reboot recovery" section accordingly in Documentation/filesystems/nfs/reexport.rst Signed-off-by: Mike Snitzer <snitzer@kernel.org> Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2025-01-14nfs: probe for LOCALIO when v3 client reconnects to serverMike Snitzer
Re-enabling NFSv3 LOCALIO is made more complex (than NFSv4) because v3 is stateless. As such, the hueristic used to identify a LOCALIO probe point is more adhoc by nature: if/when NFSv3 client IO begins to complete again in terms of normal RPC-based NFSv3 server IO, attempt nfs_local_probe_async(). Care is taken to throttle the frequency of nfs_local_probe_async(), otherwise there could be a flood of repeat calls to nfs_local_probe_async(). The throttle is admin controlled using a new module parameter for nfsv3, e.g.: echo 512 > /sys/module/nfsv3/parameters/nfs3_localio_probe_throttle Probe for NFSv3 LOCALIO every N IO requests (512 in this case). Must be power-of-2, defaults to 0 (probing disabled). On systems that expect to use LOCALIO with NFSv3 the admin should configure the 'nfs3_localio_probe_throttle' module parameter. This commit backfills module parameter documentation in localio.rst Signed-off-by: Mike Snitzer <snitzer@kernel.org> Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Anna Schumaker <anna.schumaker@oracle.com>
2025-01-14nfsd: rename nfsd_serv_ prefixed methods and variables with nfsd_net_Mike Snitzer
Also update Documentation/filesystems/nfs/localio.rst accordingly and reduce the technical documentation debt that was previously captured in that document. Signed-off-by: Mike Snitzer <snitzer@kernel.org> Reviewed-by: Jeff Layton <jlayton@kernel.org> Acked-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Anna Schumaker <anna.schumaker@oracle.com>
2025-01-14nfs/localio: add direct IO enablement with sync and async IO supportMike Snitzer
This commit simply adds the required O_DIRECT plumbing. It doesn't address the fact that NFS doesn't ensure all writes are page aligned (nor device logical block size aligned as required by O_DIRECT). Because NFS will read-modify-write for IO that isn't aligned, LOCALIO will not use O_DIRECT semantics by default if/when an application requests the use of O_DIRECT. Allow the use of O_DIRECT semantics by: 1: Adding a flag to the nfs_pgio_header struct to allow the NFS O_DIRECT layer to signal that O_DIRECT was used by the application 2: Adding a 'localio_O_DIRECT_semantics' NFS module parameter that when enabled will cause LOCALIO to use O_DIRECT semantics (this may cause IO to fail if applications do not properly align their IO). This commit is derived from code developed by Weston Andros Adamson. Signed-off-by: Mike Snitzer <snitzer@kernel.org> Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Anna Schumaker <anna.schumaker@oracle.com>
2024-10-02Merge patch series "Fixup NLM and kNFSD file lock callbacks"Christian Brauner
Benjamin Coddington <bcodding@redhat.com> says: Last year both GFS2 and OCFS2 had some work done to make their locking more robust when exported over NFS. Unfortunately, part of that work caused both NLM (for NFS v3 exports) and kNFSD (for NFSv4.1+ exports) to no longer send lock notifications to clients. This in itself is not a huge problem because most NFS clients will still poll the server in order to acquire a conflicted lock, but now that I've noticed it I can't help but try to fix it because there are big advantages for setups that might depend on timely lock notifications, and we've supported that as a feature for a long time. Its important for NLM and kNFSD that they do not block their kernel threads inside filesystem's file_lock implementations because that can produce deadlocks. We used to make sure of this by only trusting that posix_lock_file() can correctly handle blocking lock calls asynchronously, so the lock managers would only setup their file_lock requests for async callbacks if the filesystem did not define its own lock() file operation. However, when GFS2 and OCFS2 grew the capability to correctly handle blocking lock requests asynchronously, they started signalling this behavior with EXPORT_OP_ASYNC_LOCK, and the check for also trusting posix_lock_file() was inadvertently dropped, so now most filesystems no longer produce lock notifications when exported over NFS. I tried to fix this by simply including the old check for lock(), but the resulting include mess and layering violations was more than I could accept. There's a much cleaner way presented here using an fop_flag, which while potentially flag-greedy, greatly simplifies the problem and grooms the way for future uses by both filesystems and lock managers alike. * patches from https://lore.kernel.org/r/cover.1726083391.git.bcodding@redhat.com: exportfs: Remove EXPORT_OP_ASYNC_LOCK NLM/NFSD: Fix lock notifications for async-capable filesystems gfs2/ocfs2: set FOP_ASYNC_LOCK fs: Introduce FOP_ASYNC_LOCK NFS: trace: show TIMEDOUT instead of 0x6e nfsd: use system_unbound_wq for nfsd_file_gc_worker() nfsd: count nfsd_file allocations nfsd: fix refcount leak when file is unhashed after being found nfsd: remove unneeded EEXIST error check in nfsd_do_file_acquire nfsd: add list_head nf_gc to struct nfsd_file Link: https://lore.kernel.org/r/cover.1726083391.git.bcodding@redhat.com Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-10-01exportfs: Remove EXPORT_OP_ASYNC_LOCKBenjamin Coddington
Now that GFS2 and OCFS2 are signalling async ->lock() support with FOP_ASYNC_LOCK and checks for support are converted, we can remove EXPORT_OP_ASYNC_LOCK. Signed-off-by: Benjamin Coddington <bcodding@redhat.com> Link: https://lore.kernel.org/r/0a114db814fec3086f937ae3d44a086f13b8de26.1726083391.git.bcodding@redhat.com Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-09-24nfs: Fix `make htmldocs` warnings in the localio documentationAnna Schumaker
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Fixes: 92945bd81ca4 ("nfs: add Documentation/filesystems/nfs/localio.rst") Signed-off-by: Anna Schumaker <anna.schumaker@oracle.com>
2024-09-23nfs: add "NFS Client and Server Interlock" section to localio.rstMike Snitzer
This section answers a new FAQ entry: 9. How does LOCALIO make certain that object lifetimes are managed properly given NFSD and NFS operate in different contexts? See the detailed "NFS Client and Server Interlock" section below. The first half of the section details NeilBrown's elegant design for LOCALIO's nfs_uuid_t based interlock and is heavily based on Neil's "net namespace refcounting" description here: https://marc.info/?l=linux-nfs&m=172498546024767&w=2 The second half of the section details the per-cpu-refcount introduced to ensure NFSD's nfsd_serv isn't destroyed while in use by a LOCALIO client. Signed-off-by: Mike Snitzer <snitzer@kernel.org> Reviewed-by: NeilBrown <neilb@suse.de> Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Anna Schumaker <anna.schumaker@oracle.com>
2024-09-23nfs: add FAQ section to Documentation/filesystems/nfs/localio.rstTrond Myklebust
Add a FAQ section to give answers to questions that have been raised during review of the localio feature. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Co-developed-by: Mike Snitzer <snitzer@kernel.org> Signed-off-by: Mike Snitzer <snitzer@kernel.org> Reviewed-by: NeilBrown <neilb@suse.de> Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Anna Schumaker <anna.schumaker@oracle.com>
2024-09-23nfs: add Documentation/filesystems/nfs/localio.rstMike Snitzer
This document gives an overview of the LOCALIO auxiliary RPC protocol added to the Linux NFS client and server to allow them to reliably handshake to determine if they are on the same host. Once an NFS client and server handshake as "local", the client will bypass the network RPC protocol for read, write and commit operations. Due to this XDR and RPC bypass, these operations will operate faster. Signed-off-by: Mike Snitzer <snitzer@kernel.org> Reviewed-by: NeilBrown <neilb@suse.de> Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Anna Schumaker <anna.schumaker@oracle.com>
2023-11-07Merge tag 'vfs-6.7.fsid' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs Pull vfs fanotify fsid updates from Christian Brauner: "This work is part of the plan to enable fanotify to serve as a drop-in replacement for inotify. While inotify is availabe on all filesystems, fanotify currently isn't. In order to support fanotify on all filesystems two things are needed: (1) all filesystems need to support AT_HANDLE_FID (2) all filesystems need to report a non-zero f_fsid This contains (1) and allows filesystems to encode non-decodable file handlers for fanotify without implementing any exportfs operations by encoding a file id of type FILEID_INO64_GEN from i_ino and i_generation. Filesystems that want to opt out of encoding non-decodable file ids for fanotify that don't support NFS export can do so by providing an empty export_operations struct. This also partially addresses (2) by generating f_fsid for simple filesystems as well as freevxfs. Remaining filesystems will be dealt with by separate patches. Finally, this contains the patch from the current exportfs maintainers which moves exportfs under vfs with Chuck, Jeff, and Amir as maintainers and vfs.git as tree" * tag 'vfs-6.7.fsid' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: MAINTAINERS: create an entry for exportfs fs: fix build error with CONFIG_EXPORTFS=m or not defined freevxfs: derive f_fsid from bdev->bd_dev fs: report f_fsid from s_dev for "simple" filesystems exportfs: support encoding non-decodeable file handles by default exportfs: define FILEID_INO64_GEN* file handle types exportfs: make ->encode_fh() a mandatory method for NFS export exportfs: add helpers to check if filesystem can encode/decode file handles
2023-10-28exportfs: make ->encode_fh() a mandatory method for NFS exportAmir Goldstein
Rename the default helper for encoding FILEID_INO32_GEN* file handles to generic_encode_ino32_fh() and convert the filesystems that used the default implementation to use the generic helper explicitly. After this change, exportfs_encode_inode_fh() no longer has a default implementation to encode FILEID_INO32_GEN* file handles. This is a step towards allowing filesystems to encode non-decodeable file handles for fanotify without having to implement any export_operations. Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Jeff Layton <jlayton@kernel.org> Acked-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Amir Goldstein <amir73il@gmail.com> Link: https://lore.kernel.org/r/20231023180801.2953446-3-amir73il@gmail.com Acked-by: Dave Kleikamp <dave.kleikamp@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-10-16lockd: introduce safe async lock opAlexander Aring
This patch reverts mostly commit 40595cdc93ed ("nfs: block notification on fs with its own ->lock") and introduces an EXPORT_OP_ASYNC_LOCK export flag to signal that the "own ->lock" implementation supports async lock requests. The only main user is DLM that is used by GFS2 and OCFS2 filesystem. Those implement their own lock() implementation and return FILE_LOCK_DEFERRED as return value. Since commit 40595cdc93ed ("nfs: block notification on fs with its own ->lock") the DLM implementation were never updated. This patch should prepare for DLM to set the EXPORT_OP_ASYNC_LOCK export flag and update the DLM plock implementation regarding to it. Acked-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Alexander Aring <aahringo@redhat.com> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2023-08-31Merge tag 'nfsd-6.6' of git://git.kernel.org/pub/scm/linux/kernel/git/cel/linuxLinus Torvalds
Pull nfsd updates from Chuck Lever: "I'm thrilled to announce that the Linux in-kernel NFS server now offers NFSv4 write delegations. A write delegation enables a client to cache data and metadata for a single file more aggressively, reducing network round trips and server workload. Many thanks to Dai Ngo for contributing this facility, and to Jeff Layton and Neil Brown for reviewing and testing it. This release also sees the removal of all support for DES- and triple-DES-based Kerberos encryption types in the kernel's SunRPC implementation. These encryption types have been deprecated by the Internet community for years and are considered insecure. This change affects both the in-kernel NFS client and server. The server's UDP and TCP socket transports have now fully adopted David Howells' new bio_vec iterator so that no more than one sendmsg() call is needed to transmit each RPC message. In particular, this helps kTLS optimize record boundaries when sending RPC-with-TLS replies, and it takes the server a baby step closer to handling file I/O via folios. We've begun work on overhauling the SunRPC thread scheduler to remove a costly linked-list walk when looking for an idle RPC service thread to wake. The pre-requisites are included in this release. Thanks to Neil Brown for his ongoing work on this improvement" * tag 'nfsd-6.6' of git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux: (56 commits) Documentation: Add missing documentation for EXPORT_OP flags SUNRPC: Remove unused declaration rpc_modcount() SUNRPC: Remove unused declarations NFSD: da_addr_body field missing in some GETDEVICEINFO replies SUNRPC: Remove return value of svc_pool_wake_idle_thread() SUNRPC: make rqst_should_sleep() idempotent() SUNRPC: Clean up svc_set_num_threads SUNRPC: Count ingress RPC messages per svc_pool SUNRPC: Deduplicate thread wake-up code SUNRPC: Move trace_svc_xprt_enqueue SUNRPC: Add enum svc_auth_status SUNRPC: change svc_xprt::xpt_flags bits to enum SUNRPC: change svc_rqst::rq_flags bits to enum SUNRPC: change svc_pool::sp_flags bits to enum SUNRPC: change cache_head.flags bits to enum SUNRPC: remove timeout arg from svc_recv() SUNRPC: change svc_recv() to return void. SUNRPC: call svc_process() from svc_recv(). nfsd: separate nfsd_last_thread() from nfsd_put() nfsd: Simplify code around svc_exit_thread() call in nfsd() ...
2023-08-29Documentation: Add missing documentation for EXPORT_OP flagsChuck Lever
The commits that introduced these flags neglected to update the Documentation/filesystems/nfs/exporting.rst file. Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2023-08-18Documentation: Fix typosBjorn Helgaas
Fix typos in Documentation. Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Link: https://lore.kernel.org/r/20230814212822.193684-4-helgaas@kernel.org Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2023-05-22exportfs: add explicit flag to request non-decodeable file handlesAmir Goldstein
So far, all callers of exportfs_encode_inode_fh(), except for fsnotify's show_mark_fhandle(), check that filesystem can decode file handles, but we would like to add more callers that do not require a file handle that can be decoded. Introduce a flag to explicitly request a file handle that may not to be decoded later and a wrapper exportfs_encode_fid() that sets this flag and convert show_mark_fhandle() to use the new wrapper. This will be used to allow adding fanotify support to filesystems that do not support NFS export. Acked-by: Jeff Layton <jlayton@kernel.org> Acked-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Jan Kara <jack@suse.cz> Message-Id: <20230502124817.3070545-3-amir73il@gmail.com>
2023-02-15Documentation: Fix sysfs path for the NFSv4 client identifierDave Wysochanski
The sysfs path for the NFS4 client identfier should start with the path component of 'nfs' for the kset, and then the 'net' path component for the netns object, followed by the 'nfs_client' path component for the NFS client kobject, and ending with 'identifier' for the netns_client_id kobj_attribute. Fixes: a28faaddb2be ("Documentation: Add an explanation of NFSv4 client identifiers") Link: https://bugzilla.redhat.com/show_bug.cgi?id=1801326 Reviewed-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Dave Wysochanski <dwysocha@redhat.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2022-05-17Documentation: Add an explanation of NFSv4 client identifiersChuck Lever
To enable NFSv4 to work correctly, NFSv4 client identifiers have to be globally unique and persistent over client reboots. We believe that in many cases, a good default identifier can be chosen and set when a client system is imaged. Because there are many different ways a system can be imaged, provide an explanation of how NFSv4 client identifiers and principals can be set by install scripts and imaging tools. Additional cases, such as NFSv4 clients running in containers, also need unique and persistent identifiers. The Linux NFS community sets forth this explanation to aid those who create and manage container environments. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2021-09-21nfs: reexport documentationJ. Bruce Fields
We've supported reexport for a while but documentation is limited. This is mainly a simplified version of the text I wrote for the linux-nfs wiki at https://wiki.linux-nfs.org/wiki/index.php/NFS_re-export. Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2020-12-09nfsd: close cached files prior to a REMOVE or RENAME that would replace targetJeff Layton
It's not uncommon for some workloads to do a bunch of I/O to a file and delete it just afterward. If knfsd has a cached open file however, then the file may still be open when the dentry is unlinked. If the underlying filesystem is nfs, then that could trigger it to do a sillyrename. On a REMOVE or RENAME scan the nfsd_file cache for open files that correspond to the inode, and proactively unhash and put their references. This should prevent any delete-on-last-close activity from occurring, solely due to knfsd's open file cache. This must be done synchronously though so we use the variants that call flush_delayed_fput. There are deadlock possibilities if you call flush_delayed_fput while holding locks, however. In the case of nfsd_rename, we don't even do the lookups of the dentries to be renamed until we've locked for rename. Once we've figured out what the target dentry is for a rename, check to see whether there are cached open files associated with it. If there are, then unwind all of the locking, close them all, and then reattempt the rename. None of this is really necessary for "typical" filesystems though. It's mostly of use for NFS, so declare a new export op flag and use that to determine whether to close the files beforehand. Signed-off-by: Jeff Layton <jeff.layton@primarydata.com> Signed-off-by: Lance Shelton <lance.shelton@hammerspace.com> Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2020-12-09nfsd: allow filesystems to opt out of subtree checkingJeff Layton
When we start allowing NFS to be reexported, then we have some problems when it comes to subtree checking. In principle, we could allow it, but it would mean encoding parent info in the filehandles and there may not be enough space for that in a NFSv3 filehandle. To enforce this at export upcall time, we add a new export_ops flag that declares the filesystem ineligible for subtree checking. Signed-off-by: Jeff Layton <jeff.layton@primarydata.com> Signed-off-by: Lance Shelton <lance.shelton@hammerspace.com> Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2020-12-09nfsd: add a new EXPORT_OP_NOWCC flag to struct export_operationsJeff Layton
With NFSv3 nfsd will always attempt to send along WCC data to the client. This generally involves saving off the in-core inode information prior to doing the operation on the given filehandle, and then issuing a vfs_getattr to it after the op. Some filesystems (particularly clustered or networked ones) have an expensive ->getattr inode operation. Atomicity is also often difficult or impossible to guarantee on such filesystems. For those, we're best off not trying to provide WCC information to the client at all, and to simply allow it to poll for that information as needed with a GETATTR RPC. This patch adds a new flags field to struct export_operations, and defines a new EXPORT_OP_NOWCC flag that filesystems can use to indicate that nfsd should not attempt to provide WCC info in NFSv3 replies. It also adds a blurb about the new flags field and flag to the exporting documentation. The server will also now skip collecting this information for NFSv2 as well, since that info is never used there anyway. Note that this patch does not add this flag to any filesystem export_operations structures. This was originally developed to allow reexporting nfs via nfsd. Other filesystems may want to consider enabling this flag too. It's hard to tell however which ones have export operations to enable export via knfsd and which ones mostly rely on them for open-by-filehandle support, so I'm leaving that up to the individual maintainers to decide. I am cc'ing the relevant lists for those filesystems that I think may want to consider adding this though. Cc: HPDD-discuss@lists.01.org Cc: ceph-devel@vger.kernel.org Cc: cluster-devel@redhat.com Cc: fuse-devel@lists.sourceforge.net Cc: ocfs2-devel@oss.oracle.com Signed-off-by: Jeff Layton <jeff.layton@primarydata.com> Signed-off-by: Lance Shelton <lance.shelton@hammerspace.com> Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2020-09-25Documentation: update RPCSEC_GSSv3 RFC linkJ. Bruce Fields
This draft is an official RFC now. Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2020-06-26Replace HTTP links with HTTPS ones: Documentation/filesystemsAlexander A. Klimov
Rationale: Reduces attack surface on kernel devs opening the links for MITM as HTTPS traffic is much harder to manipulate. Deterministic algorithm: For each file: If not .svg: For each line: If doesn't contain `\bxmlns\b`: For each link, `\bhttp://[^# \t\r\n]*(?:\w|/)`: If both the HTTP and HTTPS versions return 200 OK and serve the same content: Replace HTTP with HTTPS. Signed-off-by: Alexander A. Klimov <grandmaster@al2klimov.de> Link: https://lore.kernel.org/r/20200621133552.46371-1-grandmaster@al2klimov.de Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-02-13Documentation: nfs: knfsd-stats: convert to ReSTDaniel W. S. Almeida
Convert knfsd-stats.txt to ReST. Content remains mostly the same. Signed-off-by: Daniel W. S. Almeida <dwlsalmeida@gmail.com> Link: https://lore.kernel.org/r/20200129044917.566906-6-dwlsalmeida@gmail.com Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-02-13Documentation: nfs: nfs41-server: convert to ReSTDaniel W. S. Almeida
Convert nfs41-server.txt to ReST. ASCII tables were converted to ReST grid table format. Signed-off-by: Daniel W. S. Almeida <dwlsalmeida@gmail.com> Link: https://lore.kernel.org/r/20200129044917.566906-5-dwlsalmeida@gmail.com Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-02-13Documentation: nfs: rpc-server-gss: convert to ReSTDaniel W. S. Almeida
Convert rpc-server-gss.txt to ReST. Content remains mostly unchanged. Signed-off-by: Daniel W. S. Almeida <dwlsalmeida@gmail.com> Link: https://lore.kernel.org/r/20200129044917.566906-4-dwlsalmeida@gmail.com Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-02-13Documentation: nfs: rpc-cache: convert to ReSTDaniel W. S. Almeida
Convert rpc-cache.txt to ReST. Changes aim to improve presentation but the content itself remains mostly the same. Signed-off-by: Daniel W. S. Almeida <dwlsalmeida@gmail.com> Link: https://lore.kernel.org/r/20200129044917.566906-3-dwlsalmeida@gmail.com Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-02-13Documentation: nfs: convert pnfs.txt to ReSTDaniel W. S. Almeida
Convert pnfs.txt to ReST. Content remains mostly unchanged. Signed-off-by: Daniel W. S. Almeida <dwlsalmeida@gmail.com> Link: https://lore.kernel.org/r/20200129044917.566906-2-dwlsalmeida@gmail.com Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-01-16Documentation: nfs: fault_injection: convert to ReSTDaniel W. S. Almeida
Convert fault_injection.txt to ReST and move it to admin-guide. Signed-off-by: Daniel W. S. Almeida <dwlsalmeida@gmail.com> Link: https://lore.kernel.org/r/f7b0cf8fb1159a668f75ce82a581e7590568c2b8.1578697871.git.dwlsalmeida@gmail.com Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-01-16Documentation: nfs: pnfs-scsi-server: convert to ReSTDaniel W. S. Almeida
Convert pnfs-scsi-server to ReST and move it to admin-guide. Content remains mostly unchanged. Signed-off-by: Daniel W. S. Almeida <dwlsalmeida@gmail.com> Link: https://lore.kernel.org/r/5c4b8af41ca0a427a3987535815bccf47a65d320.1578697871.git.dwlsalmeida@gmail.com Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-01-16Documentation: nfs: convert pnfs-block-server to ReSTDaniel W. S. Almeida
Convert pnfs-block-server.txt to ReST and move it to admin-guide. Content remains mostly unchanged. Signed-off-by: Daniel W. S. Almeida <dwlsalmeida@gmail.com> Link: https://lore.kernel.org/r/c06903760e690c16d9df92f5e75f80381d6326d8.1578697871.git.dwlsalmeida@gmail.com Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-01-16Documentation: nfs: idmapper: convert to ReSTDaniel W. S. Almeida
Convert idmapper.txt to ReST and move it to admin-guide. Content remains mostly unchanged otherwise. Signed-off-by: Daniel W. S. Almeida <dwlsalmeida@gmail.com> Link: https://lore.kernel.org/r/069e40cd551ea778538f8fe9ad15ee26e45fc748.1578697871.git.dwlsalmeida@gmail.com Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-01-16Documentation: convert nfsd-admin-interfaces to ReSTDaniel W. S. Almeida
Convert nfsd-admin-interfaces to ReST and move it into admin-guide. Content remains mostly untouched. Signed-off-by: Daniel W. S. Almeida <dwlsalmeida@gmail.com> Link: https://lore.kernel.org/r/d471305e9c96dec38f18d2ff816fca2269a88e29.1578697871.git.dwlsalmeida@gmail.com Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-01-16Documentation: nfs-rdma: convert to ReSTDaniel W. S. Almeida
Convert nfs-rdma to ReST and move it to admin-guide. Content remais mostly untouched. Also, mark the doc as obsolete. Signed-off-by: Daniel W. S. Almeida <dwlsalmeida@gmail.com> Link: https://lore.kernel.org/r/9c88f184f9de2a3eb5181563e258559efc02f58a.1578697871.git.dwlsalmeida@gmail.com Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-01-16Documentation: nfsroot.txt: convert to ReSTDaniel W. S. Almeida
Convert nfsroot.txt to RST and move it to admin-guide. Content remains mostly the same. Signed-off-by: Daniel W. S. Almeida <dwlsalmeida@gmail.com> Link: https://lore.kernel.org/r/442d35917351f5260dd8ed7362e9b5f1264ef8ad.1578697871.git.dwlsalmeida@gmail.com Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-01-16Documentation: convert nfs.txt to ReSTDaniel W. S. Almeida
This patch converts nfs.txt to RST. It also moves it to admin-guide. The reason for moving it is because this document contains information useful for system administrators, as noted on the following paragraph: 'The purpose of this document is to provide information on some of the special features of the NFS client that can be configured by system administrators'. Signed-off-by: Daniel W. S. Almeida <dwlsalmeida@gmail.com> Link: https://lore.kernel.org/r/cb9f2da2f2f6dd432b4cf9e05f79f74f4d54b6ab.1578697871.git.dwlsalmeida@gmail.com Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2019-07-31docs: fs: convert docs without extension to ReSTMauro Carvalho Chehab
There are 3 remaining files without an extension inside the fs docs dir. Manually convert them to ReST. In the case of the nfs/exporting.rst file, as the nfs docs aren't ported yet, I opted to convert and add a :orphan: there, with should be removed when it gets added into a nfs-specific part of the fs documentation. Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org> Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2019-07-15docs: early-userspace: move to driver-api guideMauro Carvalho Chehab
Those documents describe a kAPI. So, add to the driver-api book. Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
2019-07-15docs: early-userspace: convert docs to ReST and rename to *.rstMauro Carvalho Chehab
The two files there describes a Kernel API feature, used to support early userspace stuff. Prepare for moving them to the kernel API book by converting to ReST format. The conversion itself was quite trivial: just add/mark a few titles as such, add a literal block markup, add a table markup and a few blank lines, in order to make Sphinx to properly parse it. At its new index.rst, let's add a :orphan: while this is not linked to the main index.rst file, in order to avoid build warnings. Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
2018-10-30Merge tag 'nfsd-4.20' of git://linux-nfs.org/~bfields/linuxLinus Torvalds
Pull nfsd updates from Bruce Fields: "Olga added support for the NFSv4.2 asynchronous copy protocol. We already supported COPY, by copying a limited amount of data and then returning a short result, letting the client resend. The asynchronous protocol should offer better performance at the expense of some complexity. The other highlight is Trond's work to convert the duplicate reply cache to a red-black tree, and to move it and some other server caches to RCU. (Previously these have meant taking global spinlocks on every RPC) Otherwise, some RDMA work and miscellaneous bugfixes" * tag 'nfsd-4.20' of git://linux-nfs.org/~bfields/linux: (30 commits) lockd: fix access beyond unterminated strings in prints nfsd: Fix an Oops in free_session() nfsd: correctly decrement odstate refcount in error path svcrdma: Increase the default connection credit limit svcrdma: Remove try_module_get from backchannel svcrdma: Remove ->release_rqst call in bc reply handler svcrdma: Reduce max_send_sges nfsd: fix fall-through annotations knfsd: Improve lookup performance in the duplicate reply cache using an rbtree knfsd: Further simplify the cache lookup knfsd: Simplify NFS duplicate replay cache knfsd: Remove dead code from nfsd_cache_lookup SUNRPC: Simplify TCP receive code SUNRPC: Replace the cache_detail->hash_lock with a regular spinlock SUNRPC: Remove non-RCU protected lookup NFS: Fix up a typo in nfs_dns_ent_put NFS: Lockless DNS lookups knfsd: Lockless lookup of NFSv4 identities. SUNRPC: Lockless server RPCSEC_GSS context lookup knfsd: Allow lockless lookups of the exports ...
2018-10-29SUNRPC: Remove non-RCU protected lookupTrond Myklebust
Clean up the cache code by removing the non-RCU protected lookup. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>