kernel/linux.git/fs/nfsd/filecache.h, branch v7.1

nfsd: allow filecache to hold S_IFDIR files

2025-11-12T08:38:36+00:00

The filecache infrastructure will only handle S_IFREG files at the moment. Directory delegations will require adding support for opening S_IFDIR inodes. Plumb a "type" argument into nfsd_file_do_acquire() and have all of the existing callers set it to S_IFREG. Add a new nfsd_file_acquire_dir() wrapper that nfsd can call to request a nfsd_file that holds a directory open. For now, there is no need for a fsnotify_mark for directories, as CB_NOTIFY is not yet supported. Change nfsd_file_do_acquire() to avoid allocating one for non-S_IFREG inodes. Reviewed-by: Chuck Lever Reviewed-by: NeilBrown Signed-off-by: Jeff Layton Link: https://patch.msgid.link/20251111-dir-deleg-ro-v6-14-52f3feebb2f2@kernel.org Signed-off-by: Christian Brauner

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() ...

NFSD: filecache: add STATX_DIOALIGN and STATX_DIO_READ_ALIGN support

2025-09-30T20:10:05+00:00

Use STATX_DIOALIGN and STATX_DIO_READ_ALIGN to get DIO alignment attributes from the underlying filesystem and store them in the associated nfsd_file. This is done when the nfsd_file is first opened for each regular file. Signed-off-by: Mike Snitzer Reviewed-by: Jeff Layton Reviewed-by: NeilBrown Signed-off-by: Chuck Lever Acked-by: Chuck Lever Signed-off-by: Anna Schumaker

nfsd: discard nfsd_file_get_local()

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

This interface was deprecated by commit e6f7e1487ab5 ("nfs_localio: simplify interface to nfsd for getting nfsd_file") and is now unused. So let's remove it. Signed-off-by: NeilBrown Reviewed-by: Mike Snitzer Reviewed-by: Jeff Layton Signed-off-by: Chuck Lever

nfs_localio: change nfsd_file_put_local() to take a pointer to __rcu pointer

2025-05-28T21:17:14+00:00

Instead of calling xchg() and unrcu_pointer() before nfsd_file_put_local(), we now pass pointer to the __rcu pointer and call xchg() and unrcu_pointer() inside that function. Where unrcu_pointer() is currently called the internals of "struct nfsd_file" are not known and that causes older compilers such as gcc-8 to complain. In some cases we have a __kernel (aka normal) pointer not an __rcu pointer so we need to cast it to __rcu first. This is strictly a weakening so no information is lost. Somewhat surprisingly, this cast is accepted by gcc-8. This has the pleasing result that the cmpxchg() which sets ro_file and rw_file, and also the xchg() which clears them, are both now in the nfsd code. Reported-by: Pali Rohár Reported-by: Vincent Mailhol Fixes: 86e00412254a ("nfs: cache all open LOCALIO nfsd_file(s) in client") Signed-off-by: NeilBrown Signed-off-by: Anna Schumaker

nfs_localio: always hold nfsd net ref with nfsd_file ref

2025-05-28T21:17:14+00:00

Having separate nfsd_file_put and nfsd_file_put_local in struct nfsd_localio_operations doesn't make much sense. The difference is that nfsd_file_put doesn't drop a reference to the nfs_net which is what keeps nfsd from shutting down. Currently, if nfsd tries to shutdown it will invalidate the files stored in the list from the nfs_uuid and this will drop all references to the nfsd net that the client holds. But the client could still hold some references to nfsd_files for active IO. So nfsd might think is has completely shut down local IO, but hasn't and has no way to wait for those active IO requests to complete. So this patch changes nfsd_file_get to nfsd_file_get_local and has it increase the ref count on the nfsd net and it replaces all calls to ->nfsd_put_file to ->nfsd_put_file_local. It also changes ->nfsd_open_local_fh to return with the refcount on the net elevated precisely when a valid nfsd_file is returned. This means that whenever the client holds a valid nfsd_file, there will be an associated count on the nfsd net, and so the count can only reach zero when all nfsd_files have been returned. nfs_local_file_put() is changed to call nfs_to_nfsd_file_put_local() instead of replacing calls to one with calls to the other because this will help a later patch which changes nfs_to_nfsd_file_put_local() to take an __rcu pointer while nfs_local_file_put() doesn't. Fixes: 86e00412254a ("nfs: cache all open LOCALIO nfsd_file(s) in client") Signed-off-by: NeilBrown Signed-off-by: Anna Schumaker

nfsd: filecache: drop the list_lru lock during lock gc scans

2025-03-10T13:11:08+00:00

Under a high NFSv3 load with lots of different files being accessed, the LRU list of garbage-collectable files can become quite long. Asking list_lru_scan_node() to scan the whole list can result in a long period during which a spinlock is held, blocking the addition of new LRU items. So ask list_lru_scan_node() to scan only a few entries at a time, and repeat until the scan is complete. If the shrinker runs between two consecutive calls of list_lru_scan_node() it could invalidate the "remaining" counter which could lead to premature freeing. So add a spinlock to avoid that. Signed-off-by: NeilBrown Reviewed-by: Jeff Layton Signed-off-by: Chuck Lever

nfsd: filecache: introduce NFSD_FILE_RECENT

2025-03-10T13:11:07+00:00

The filecache lru is walked in 2 circumstances for 2 different reasons. 1/ When called from the shrinker we want to discard the first few entries on the list, ignoring any with NFSD_FILE_REFERENCED set because they should really be at the end of the LRU as they have been referenced recently. So those ones are ROTATED. 2/ When called from the nfsd_file_gc() timer function we want to discard anything that hasn't been used since before the previous call, and mark everything else as unused at this point in time. Using the same flag for both of these can result in some unexpected outcomes. If the shrinker callback clears NFSD_FILE_REFERENCED then nfsd_file_gc() will think the file hasn't been used in a while, while really it has. I think it is easier to reason about the behaviour if we instead have two flags. NFSD_FILE_REFERENCED means "this should be at the end of the LRU, please put it there when convenient" NFSD_FILE_RECENT means "this has been used recently - since the last run of nfsd_file_gc() When either caller finds an NFSD_FILE_REFERENCED entry, that entry should be moved to the end of the LRU and the flag cleared. This can safely happen at any time. The actual order on the lru might not be strictly least-recently-used, but that is normal for linux lrus. The shrinker callback can ignore the "recent" flag. If it ends up freeing something that is "recent" that simply means that memory pressure is sufficient to limit the acceptable cache age to less than the nfsd_file_gc frequency. The gc callback should primarily focus on NFSD_FILE_RECENT. It should free everything that doesn't have this flag set, and should clear the flag on everything else. When it clears the flag it is convenient to clear the "REFERENCED" flag and move to the end of the LRU too. With this, calls from the shrinker do not prematurely age files. It will focus only on freeing those that are least recently used. Signed-off-by: NeilBrown Reviewed-by: Jeff Layton Signed-off-by: Chuck Lever

nfs_common: must not hold RCU while calling nfsd_file_put_local

2024-11-19T01:23:12+00:00

Move holding the RCU from nfs_to_nfsd_file_put_local to nfs_to_nfsd_net_put. It is the call to nfs_to->nfsd_serv_put that requires the RCU anyway (the puts for nfsd_file and netns were combined to avoid an extra indirect reference but that micro-optimization isn't possible now). This fixes xfstests generic/013 and it triggering: "Voluntary context switch within RCU read-side critical section!" [ 143.545738] Call Trace: [ 143.546206] [ 143.546625] ? show_regs+0x6d/0x80 [ 143.547267] ? __warn+0x91/0x140 [ 143.547951] ? rcu_note_context_switch+0x496/0x5d0 [ 143.548856] ? report_bug+0x193/0x1a0 [ 143.549557] ? handle_bug+0x63/0xa0 [ 143.550214] ? exc_invalid_op+0x1d/0x80 [ 143.550938] ? asm_exc_invalid_op+0x1f/0x30 [ 143.551736] ? rcu_note_context_switch+0x496/0x5d0 [ 143.552634] ? wakeup_preempt+0x62/0x70 [ 143.553358] __schedule+0xaa/0x1380 [ 143.554025] ? _raw_spin_unlock_irqrestore+0x12/0x40 [ 143.554958] ? try_to_wake_up+0x1fe/0x6b0 [ 143.555715] ? wake_up_process+0x19/0x20 [ 143.556452] schedule+0x2e/0x120 [ 143.557066] schedule_preempt_disabled+0x19/0x30 [ 143.557933] rwsem_down_read_slowpath+0x24d/0x4a0 [ 143.558818] ? xfs_efi_item_format+0x50/0xc0 [xfs] [ 143.559894] down_read+0x4e/0xb0 [ 143.560519] xlog_cil_commit+0x1b2/0xbc0 [xfs] [ 143.561460] ? _raw_spin_unlock+0x12/0x30 [ 143.562212] ? xfs_inode_item_precommit+0xc7/0x220 [xfs] [ 143.563309] ? xfs_trans_run_precommits+0x69/0xd0 [xfs] [ 143.564394] __xfs_trans_commit+0xb5/0x330 [xfs] [ 143.565367] xfs_trans_roll+0x48/0xc0 [xfs] [ 143.566262] xfs_defer_trans_roll+0x57/0x100 [xfs] [ 143.567278] xfs_defer_finish_noroll+0x27a/0x490 [xfs] [ 143.568342] xfs_defer_finish+0x1a/0x80 [xfs] [ 143.569267] xfs_bunmapi_range+0x4d/0xb0 [xfs] [ 143.570208] xfs_itruncate_extents_flags+0x13d/0x230 [xfs] [ 143.571353] xfs_free_eofblocks+0x12e/0x190 [xfs] [ 143.572359] xfs_file_release+0x12d/0x140 [xfs] [ 143.573324] __fput+0xe8/0x2d0 [ 143.573922] __fput_sync+0x1d/0x30 [ 143.574574] nfsd_filp_close+0x33/0x60 [nfsd] [ 143.575430] nfsd_file_free+0x96/0x150 [nfsd] [ 143.576274] nfsd_file_put+0xf7/0x1a0 [nfsd] [ 143.577104] nfsd_file_put_local+0x18/0x30 [nfsd] [ 143.578070] nfs_close_local_fh+0x101/0x110 [nfs_localio] [ 143.579079] __put_nfs_open_context+0xc9/0x180 [nfs] [ 143.580031] nfs_file_clear_open_context+0x4a/0x60 [nfs] [ 143.581038] nfs_file_release+0x3e/0x60 [nfs] [ 143.581879] __fput+0xe8/0x2d0 [ 143.582464] __fput_sync+0x1d/0x30 [ 143.583108] __x64_sys_close+0x41/0x80 [ 143.583823] x64_sys_call+0x189a/0x20d0 [ 143.584552] do_syscall_64+0x64/0x170 [ 143.585240] entry_SYSCALL_64_after_hwframe+0x76/0x7e [ 143.586185] RIP: 0033:0x7f3c5153efd7 Fixes: 65f2a5c36635 ("nfs_common: fix race in NFS calls to nfsd_file_put_local() and nfsd_serv_put()") Signed-off-by: Mike Snitzer Reviewed-by: NeilBrown Reviewed-by: Jeff Layton Signed-off-by: Chuck Lever

nfs_common: prepare for the NFS client to use nfsd_file for LOCALIO

2024-09-23T19:03:30+00:00

The next commit will introduce nfsd_open_local_fh() which returns an nfsd_file structure. This commit exposes LOCALIO's required NFSD symbols to the NFS client: - Make nfsd_open_local_fh() symbol and other required NFSD symbols available to NFS in a global 'nfs_to' nfsd_localio_operations struct (global access suggested by Trond, nfsd_localio_operations suggested by NeilBrown). The next commit will also introduce nfsd_localio_ops_init() that init_nfsd() will call to initialize 'nfs_to'. - Introduce nfsd_file_file() that provides access to nfsd_file's backing file. Keeps nfsd_file structure opaque to NFS client (as suggested by Jeff Layton). - Introduce nfsd_file_put_local() that will put the reference to the nfsd_file's associated nn->nfsd_serv and then put the reference to the nfsd_file (as suggested by NeilBrown). Suggested-by: Trond Myklebust # nfs_to Suggested-by: NeilBrown # nfsd_localio_operations Suggested-by: Jeff Layton # nfsd_file_file Signed-off-by: Mike Snitzer Reviewed-by: NeilBrown Reviewed-by: Jeff Layton Signed-off-by: Anna Schumaker