Commit Graph

3421 Commits

Author SHA1 Message Date
Chuck Lever
cb7ec76e73 NFSD: nfsd_file_hash_remove can compute hashval
Remove an unnecessary use of nf_hashval.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2022-07-29 20:12:01 -04:00
Chuck Lever
a845511007 NFSD: Refactor __nfsd_file_close_inode()
The code that computes the hashval is the same in both callers.

To prevent them from going stale, reframe the documenting comments
to remove descriptions of the underlying hash table structure, which
is about to be replaced.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2022-07-29 20:11:50 -04:00
Chuck Lever
8755326399 NFSD: nfsd_file_unhash can compute hashval from nf->nf_inode
Remove an unnecessary usage of nf_hashval.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2022-07-29 20:11:42 -04:00
Chuck Lever
f53cef15dd NFSD: Remove lockdep assertion from unhash_and_release_locked()
IIUC, holding the hash bucket lock is needed only in
nfsd_file_unhash, and there is already a lockdep assertion there.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2022-07-29 20:11:41 -04:00
Chuck Lever
54f7df7094 NFSD: No longer record nf_hashval in the trace log
I'm about to replace nfsd_file_hashtbl with an rhashtable. The
individual hash values will no longer be visible or relevant, so
remove them from the tracepoints.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2022-07-29 20:11:29 -04:00
Chuck Lever
6df1941136 NFSD: Never call nfsd_file_gc() in foreground paths
The checks in nfsd_file_acquire() and nfsd_file_put() that directly
invoke filecache garbage collection are intended to keep cache
occupancy between a low- and high-watermark. The reason to limit the
capacity of the filecache is to keep filecache lookups reasonably
fast.

However, invoking garbage collection at those points has some
undesirable negative impacts. Files that are held open by NFSv4
clients often push the occupancy of the filecache over these
watermarks. At that point:

- Every call to nfsd_file_acquire() and nfsd_file_put() results in
  an LRU walk. This has the same effect on lookup latency as long
  chains in the hash table.
- Garbage collection will then run on every nfsd thread, causing a
  lot of unnecessary lock contention.
- Limiting cache capacity pushes out files used only by NFSv3
  clients, which are the type of files the filecache is supposed to
  help.

To address those negative impacts, remove the direct calls to the
garbage collector. Subsequent patches will address maintaining
lookup efficiency as cache capacity increases.

Suggested-by: Wang Yugui <wangyugui@e16-tech.com>
Suggested-by: Dave Chinner <david@fromorbit.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2022-07-29 20:11:19 -04:00
Chuck Lever
edead3a558 NFSD: Fix the filecache LRU shrinker
Without LRU item rotation, the shrinker visits only a few items on
the end of the LRU list, and those would always be long-term OPEN
files for NFSv4 workloads. That makes the filecache shrinker
completely ineffective.

Adopt the same strategy as the inode LRU by using LRU_ROTATE.

Suggested-by: Dave Chinner <david@fromorbit.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2022-07-29 20:11:19 -04:00
Chuck Lever
4a0e73e635 NFSD: Leave open files out of the filecache LRU
There have been reports of problems when running fstests generic/531
against Linux NFS servers with NFSv4. The NFS server that hosts the
test's SCRATCH_DEV suffers from CPU soft lock-ups during the test.
Analysis shows that:

fs/nfsd/filecache.c
 482                 ret = list_lru_walk(&nfsd_file_lru,
 483                                 nfsd_file_lru_cb,
 484                                 &head, LONG_MAX);

causes nfsd_file_gc() to walk the entire length of the filecache LRU
list every time it is called (which is quite frequently). The walk
holds a spinlock the entire time that prevents other nfsd threads
from accessing the filecache.

What's more, for NFSv4 workloads, none of the items that are visited
during this walk may be evicted, since they are all files that are
held OPEN by NFS clients.

Address this by ensuring that open files are not kept on the LRU
list.

Reported-by: Frank van der Linden <fllinden@amazon.com>
Reported-by: Wang Yugui <wangyugui@e16-tech.com>
Link: https://bugzilla.linux-nfs.org/show_bug.cgi?id=386
Suggested-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2022-07-29 20:10:08 -04:00
Chuck Lever
c46203acdd NFSD: Trace filecache LRU activity
Observe the operation of garbage collection and the lifetime of
filecache items.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2022-07-29 20:10:07 -04:00
Chuck Lever
668ed92e65 NFSD: WARN when freeing an item still linked via nf_lru
Add a guardrail to prevent freeing memory that is still on a list.
This includes either a dispose list or the LRU list.

This is the sign of a bug, but this class of bugs can be detected
so that they don't endanger system stability, especially while
debugging.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2022-07-29 20:10:07 -04:00
Chuck Lever
2e6c6e4c43 NFSD: Hook up the filecache stat file
There has always been the capability of exporting filecache metrics
via /proc, but it was never hooked up. Let's surface these metrics
to enable better observability of the filecache.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2022-07-29 20:10:07 -04:00
Chuck Lever
8b330f7804 NFSD: Zero counters when the filecache is re-initialized
If nfsd_file_cache_init() is called after a shutdown, be sure the
stat counters are reset.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2022-07-29 20:10:07 -04:00
Chuck Lever
df2aff524f NFSD: Record number of flush calls
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2022-07-29 20:10:07 -04:00
Chuck Lever
94660cc19c NFSD: Report the number of items evicted by the LRU walk
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2022-07-29 20:10:07 -04:00
Chuck Lever
39f1d1ff81 NFSD: Refactor nfsd_file_lru_scan()
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2022-07-29 20:09:55 -04:00
Chuck Lever
3bc6d3470f NFSD: Refactor nfsd_file_gc()
Refactor nfsd_file_gc() to use the new list_lru helper.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2022-07-29 20:09:48 -04:00
Chuck Lever
0bac5a264d NFSD: Add nfsd_file_lru_dispose_list() helper
Refactor the invariant part of nfsd_file_lru_walk_list() into a
separate helper function.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2022-07-29 20:09:39 -04:00
Chuck Lever
904940e94a NFSD: Report average age of filecache items
This is a measure of how long items stay in the filecache, to help
assess how efficient the cache is.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2022-07-29 20:09:22 -04:00
Chuck Lever
d63293272a NFSD: Report count of freed filecache items
Surface the count of freed nfsd_file items.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2022-07-29 20:09:22 -04:00
Chuck Lever
29d4bdbbb9 NFSD: Report count of calls to nfsd_file_acquire()
Count the number of successful acquisitions that did not create a
file (ie, acquisitions that do not result in a compulsory cache
miss). This count can be compared directly with the reported hit
count to compute a hit ratio.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2022-07-29 20:09:22 -04:00
Chuck Lever
0fd244c115 NFSD: Report filecache LRU size
Surface the NFSD filecache's LRU list length to help field
troubleshooters monitor filecache issues.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2022-07-29 20:09:21 -04:00
Chuck Lever
ca3f9acb6d NFSD: Demote a WARN to a pr_warn()
The call trace doesn't add much value, but it sure is noisy.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2022-07-29 20:09:21 -04:00
Colin Ian King
842e00ac3a nfsd: remove redundant assignment to variable len
Variable len is being assigned a value zero and this is never
read, it is being re-assigned later. The assignment is redundant
and can be removed.

Cleans up clang scan-build warning:
fs/nfsd/nfsctl.c:636:2: warning: Value stored to 'len' is never read

Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2022-07-29 20:08:56 -04:00
Zhang Jiaming
f532c9ff10 NFSD: Fix space and spelling mistake
Add a blank space after ','.
Change 'succesful' to 'successful'.

Signed-off-by: Zhang Jiaming <jiaming@nfschina.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2022-07-29 20:08:56 -04:00
Chuck Lever
0513828855 NFSD: Instrument fh_verify()
Capture file handles and how they map to local inodes. In particular,
NFSv4 PUTFH uses fh_verify() so we can now observe which file handles
are the target of OPEN, LOOKUP, RENAME, and so on.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2022-07-29 20:08:56 -04:00
Jeff Layton
23ba98de6d nfsd: eliminate the NFSD_FILE_BREAK_* flags
We had a report from the spring Bake-a-thon of data corruption in some
nfstest_interop tests. Looking at the traces showed the NFS server
allowing a v3 WRITE to proceed while a read delegation was still
outstanding.

Currently, we only set NFSD_FILE_BREAK_* flags if
NFSD_MAY_NOT_BREAK_LEASE was set when we call nfsd_file_alloc.
NFSD_MAY_NOT_BREAK_LEASE was intended to be set when finding files for
COMMIT ops, where we need a writeable filehandle but don't need to
break read leases.

It doesn't make any sense to consult that flag when allocating a file
since the file may be used on subsequent calls where we do want to break
the lease (and the usage of it here seems to be reverse from what it
should be anyway).

Also, after calling nfsd_open_break_lease, we don't want to clear the
BREAK_* bits. A lease could end up being set on it later (more than
once) and we need to be able to break those leases as well.

This means that the NFSD_FILE_BREAK_* flags now just mirror
NFSD_MAY_{READ,WRITE} flags, so there's no need for them at all. Just
drop those flags and unconditionally call nfsd_open_break_lease every
time.

Reported-by: Olga Kornieskaia <kolga@netapp.com>
Link: https://bugzilla.redhat.com/show_bug.cgi?id=2107360
Fixes: 65294c1f2c (nfsd: add a new struct file caching facility to nfsd)
Cc: <stable@vger.kernel.org> # 5.4.x : bb283ca18d NFSD: Clean up the show_nf_flags() macro
Cc: <stable@vger.kernel.org> # 5.4.x
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2022-07-29 20:08:56 -04:00
Linus Torvalds
a24a6c05ff Notable regression fixes:
- Enable SETATTR(time_create) to fix regression with Mac OS clients
 - Fix a lockd crasher and broken NLM UNLCK behavior
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Merge tag 'nfsd-5.19-3' of git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux

Pull nfsd fixes from Chuck Lever:
 "Notable regression fixes:

   - Enable SETATTR(time_create) to fix regression with Mac OS clients

   - Fix a lockd crasher and broken NLM UNLCK behavior"

* tag 'nfsd-5.19-3' of git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux:
  lockd: fix nlm_close_files
  lockd: set fl_owner when unlocking files
  NFSD: Decode NFSv4 birth time attribute
2022-07-14 12:29:43 -07:00
Chuck Lever
5b2f3e0777 NFSD: Decode NFSv4 birth time attribute
NFSD has advertised support for the NFSv4 time_create attribute
since commit e377a3e698 ("nfsd: Add support for the birth time
attribute").

Igor Mammedov reports that Mac OS clients attempt to set the NFSv4
birth time attribute via OPEN(CREATE) and SETATTR if the server
indicates that it supports it, but since the above commit was
merged, those attempts now fail.

Table 5 in RFC 8881 lists the time_create attribute as one that can
be both set and retrieved, but the above commit did not add server
support for clients to provide a time_create attribute. IMO that's
a bug in our implementation of the NFSv4 protocol, which this commit
addresses.

Whether NFSD silently ignores the new birth time or actually sets it
is another matter. I haven't found another filesystem service in the
Linux kernel that enables users or clients to modify a file's birth
time attribute.

This commit reflects my (perhaps incorrect) understanding of whether
Linux users can set a file's birth time. NFSD will now recognize a
time_create attribute but it ignores its value. It clears the
time_create bit in the returned attribute bitmask to indicate that
the value was not used.

Reported-by: Igor Mammedov <imammedo@redhat.com>
Fixes: e377a3e698 ("nfsd: Add support for the birth time attribute")
Tested-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2022-07-11 13:52:22 -04:00
Linus Torvalds
69cb6c6556 Notable regression fixes:
- Fix NFSD crash during NFSv4.2 READ_PLUS operation
 - Fix incorrect status code returned by COMMIT operation
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Merge tag 'nfsd-5.19-2' of git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux

Pull nfsd fixes from Chuck Lever:
 "Notable regression fixes:

   - Fix NFSD crash during NFSv4.2 READ_PLUS operation

   - Fix incorrect status code returned by COMMIT operation"

* tag 'nfsd-5.19-2' of git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux:
  SUNRPC: Fix READ_PLUS crasher
  NFSD: restore EINVAL error translation in nfsd_commit()
2022-07-02 11:20:56 -07:00
Amir Goldstein
868f9f2f8e vfs: fix copy_file_range() regression in cross-fs copies
A regression has been reported by Nicolas Boichat, found while using the
copy_file_range syscall to copy a tracefs file.

Before commit 5dae222a5f ("vfs: allow copy_file_range to copy across
devices") the kernel would return -EXDEV to userspace when trying to
copy a file across different filesystems.  After this commit, the
syscall doesn't fail anymore and instead returns zero (zero bytes
copied), as this file's content is generated on-the-fly and thus reports
a size of zero.

Another regression has been reported by He Zhe - the assertion of
WARN_ON_ONCE(ret == -EOPNOTSUPP) can be triggered from userspace when
copying from a sysfs file whose read operation may return -EOPNOTSUPP.

Since we do not have test coverage for copy_file_range() between any two
types of filesystems, the best way to avoid these sort of issues in the
future is for the kernel to be more picky about filesystems that are
allowed to do copy_file_range().

This patch restores some cross-filesystem copy restrictions that existed
prior to commit 5dae222a5f ("vfs: allow copy_file_range to copy across
devices"), namely, cross-sb copy is not allowed for filesystems that do
not implement ->copy_file_range().

Filesystems that do implement ->copy_file_range() have full control of
the result - if this method returns an error, the error is returned to
the user.  Before this change this was only true for fs that did not
implement the ->remap_file_range() operation (i.e.  nfsv3).

Filesystems that do not implement ->copy_file_range() still fall-back to
the generic_copy_file_range() implementation when the copy is within the
same sb.  This helps the kernel can maintain a more consistent story
about which filesystems support copy_file_range().

nfsd and ksmbd servers are modified to fall-back to the
generic_copy_file_range() implementation in case vfs_copy_file_range()
fails with -EOPNOTSUPP or -EXDEV, which preserves behavior of
server-side-copy.

fall-back to generic_copy_file_range() is not implemented for the smb
operation FSCTL_DUPLICATE_EXTENTS_TO_FILE, which is arguably a correct
change of behavior.

Fixes: 5dae222a5f ("vfs: allow copy_file_range to copy across devices")
Link: https://lore.kernel.org/linux-fsdevel/20210212044405.4120619-1-drinkcat@chromium.org/
Link: https://lore.kernel.org/linux-fsdevel/CANMq1KDZuxir2LM5jOTm0xx+BnvW=ZmpsG47CyHFJwnw7zSX6Q@mail.gmail.com/
Link: https://lore.kernel.org/linux-fsdevel/20210126135012.1.If45b7cdc3ff707bc1efa17f5366057d60603c45f@changeid/
Link: https://lore.kernel.org/linux-fsdevel/20210630161320.29006-1-lhenriques@suse.de/
Reported-by: Nicolas Boichat <drinkcat@chromium.org>
Reported-by: kernel test robot <oliver.sang@intel.com>
Signed-off-by: Luis Henriques <lhenriques@suse.de>
Fixes: 64bf5ff58d ("vfs: no fallback for ->copy_file_range")
Link: https://lore.kernel.org/linux-fsdevel/20f17f64-88cb-4e80-07c1-85cb96c83619@windriver.com/
Reported-by: He Zhe <zhe.he@windriver.com>
Tested-by: Namjae Jeon <linkinjeon@kernel.org>
Tested-by: Luis Henriques <lhenriques@suse.de>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2022-06-30 15:16:38 -07:00
Alexey Khoroshilov
8a9ffb8c85 NFSD: restore EINVAL error translation in nfsd_commit()
commit 555dbf1a9a ("nfsd: Replace use of rwsem with errseq_t")
incidentally broke translation of -EINVAL to nfserr_notsupp.
The patch restores that.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
Fixes: 555dbf1a9a ("nfsd: Replace use of rwsem with errseq_t")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2022-06-27 10:33:05 -04:00
Linus Torvalds
0885eacdc8 Notable changes:
- There is now a backup maintainer for NFSD
 
 Notable fixes:
 - Prevent array overruns in svc_rdma_build_writes()
 - Prevent buffer overruns when encoding NFSv3 READDIR results
 - Fix a potential UAF in nfsd_file_put()
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Merge tag 'nfsd-5.19-1' of git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux

Pull nfsd fixes from Chuck Lever:
 "Notable changes:

   - There is now a backup maintainer for NFSD

  Notable fixes:

   - Prevent array overruns in svc_rdma_build_writes()

   - Prevent buffer overruns when encoding NFSv3 READDIR results

   - Fix a potential UAF in nfsd_file_put()"

* tag 'nfsd-5.19-1' of git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux:
  SUNRPC: Remove pointer type casts from xdr_get_next_encode_buffer()
  SUNRPC: Clean up xdr_get_next_encode_buffer()
  SUNRPC: Clean up xdr_commit_encode()
  SUNRPC: Optimize xdr_reserve_space()
  SUNRPC: Fix the calculation of xdr->end in xdr_get_next_encode_buffer()
  SUNRPC: Trap RDMA segment overflows
  NFSD: Fix potential use-after-free in nfsd_file_put()
  MAINTAINERS: reciprocal co-maintainership for file locking and nfsd
2022-06-10 17:28:43 -07:00
Chuck Lever
b6c71c66b0 NFSD: Fix potential use-after-free in nfsd_file_put()
nfsd_file_put_noref() can free @nf, so don't dereference @nf
immediately upon return from nfsd_file_put_noref().

Suggested-by: Trond Myklebust <trondmy@hammerspace.com>
Fixes: 999397926a ("nfsd: Clean up nfsd_file_put()")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2022-06-02 13:05:58 -04:00
Linus Torvalds
6d29d7fe4f NFSD 5.19 Release Notes
We introduce "courteous server" in this release. Previously NFSD
 would purge open and lock state for an unresponsive client after
 one lease period (typically 90 seconds). Now, after one lease
 period, another client can open and lock those files and the
 unresponsive client's lease is purged; otherwise if the unrespon-
 sive client's open and lock state is uncontended, the server retains
 that open and lock state for up to 24 hours, allowing the client's
 workload to resume after a lengthy network partition.
 
 A longstanding issue with NFSv4 file creation is also addressed.
 Previously a file creation can fail internally, returning an error
 to the client, but leave the newly created file in place as an
 artifact. The file creation code path has been reorganized so that
 internal failures and race conditions are less likely to result in
 an unwanted file creation.
 
 A fault injector has been added to help exercise paths that are run
 during kernel metadata cache invalidation. These caches contain
 information maintained by user space about exported filesystems.
 Many of our test workloads do not trigger cache invalidation.
 
 There is one patch that is needed to support PREEMPT_RT and a fix
 for an ancient "sleep while spin-locked" splat that seems to have
 become easier to hit since v5.18-rc3.
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Merge tag 'nfsd-5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux

Pull nfsd updates from Chuck Lever:
 "We introduce 'courteous server' in this release. Previously NFSD would
  purge open and lock state for an unresponsive client after one lease
  period (typically 90 seconds). Now, after one lease period, another
  client can open and lock those files and the unresponsive client's
  lease is purged; otherwise if the unresponsive client's open and lock
  state is uncontended, the server retains that open and lock state for
  up to 24 hours, allowing the client's workload to resume after a
  lengthy network partition.

  A longstanding issue with NFSv4 file creation is also addressed.
  Previously a file creation can fail internally, returning an error to
  the client, but leave the newly created file in place as an artifact.
  The file creation code path has been reorganized so that internal
  failures and race conditions are less likely to result in an unwanted
  file creation.

  A fault injector has been added to help exercise paths that are run
  during kernel metadata cache invalidation. These caches contain
  information maintained by user space about exported filesystems. Many
  of our test workloads do not trigger cache invalidation.

  There is one patch that is needed to support PREEMPT_RT and a fix for
  an ancient 'sleep while spin-locked' splat that seems to have become
  easier to hit since v5.18-rc3"

* tag 'nfsd-5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux: (36 commits)
  NFSD: nfsd_file_put() can sleep
  NFSD: Add documenting comment for nfsd4_release_lockowner()
  NFSD: Modernize nfsd4_release_lockowner()
  NFSD: Fix possible sleep during nfsd4_release_lockowner()
  nfsd: destroy percpu stats counters after reply cache shutdown
  nfsd: Fix null-ptr-deref in nfsd_fill_super()
  nfsd: Unregister the cld notifier when laundry_wq create failed
  SUNRPC: Use RMW bitops in single-threaded hot paths
  NFSD: Clean up the show_nf_flags() macro
  NFSD: Trace filecache opens
  NFSD: Move documenting comment for nfsd4_process_open2()
  NFSD: Fix whitespace
  NFSD: Remove dprintk call sites from tail of nfsd4_open()
  NFSD: Instantiate a struct file when creating a regular NFSv4 file
  NFSD: Clean up nfsd_open_verified()
  NFSD: Remove do_nfsd_create()
  NFSD: Refactor NFSv4 OPEN(CREATE)
  NFSD: Refactor NFSv3 CREATE
  NFSD: Refactor nfsd_create_setattr()
  NFSD: Avoid calling fh_drop_write() twice in do_nfsd_create()
  ...
2022-05-26 20:52:24 -07:00
Chuck Lever
08af54b3e5 NFSD: nfsd_file_put() can sleep
Now that there are no more callers of nfsd_file_put() that might
hold a spin lock, ensure the lockdep infrastructure can catch
newly introduced calls to nfsd_file_put() made while a spinlock
is held.

Link: https://lore.kernel.org/linux-nfs/ece7fd1d-5fb3-5155-54ba-347cfc19bd9a@oracle.com/T/#mf1855552570cf9a9c80d1e49d91438cd9085aada
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
2022-05-26 10:50:51 -04:00
Chuck Lever
043862b09c NFSD: Add documenting comment for nfsd4_release_lockowner()
And return explicit nfserr values that match what is documented in the
new comment / API contract.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2022-05-26 10:50:50 -04:00
Chuck Lever
bd8fdb6e54 NFSD: Modernize nfsd4_release_lockowner()
Refactor: Use existing helpers that other lock operations use. This
change removes several automatic variables, so re-organize the
variable declarations for readability.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2022-05-26 10:50:50 -04:00
Chuck Lever
ce3c4ad7f4 NFSD: Fix possible sleep during nfsd4_release_lockowner()
nfsd4_release_lockowner() holds clp->cl_lock when it calls
check_for_locks(). However, check_for_locks() calls nfsd_file_get()
/ nfsd_file_put() to access the backing inode's flc_posix list, and
nfsd_file_put() can sleep if the inode was recently removed.

Let's instead rely on the stateowner's reference count to gate
whether the release is permitted. This should be a reliable
indication of locks-in-use since file lock operations and
->lm_get_owner take appropriate references, which are released
appropriately when file locks are removed.

Reported-by: Dai Ngo <dai.ngo@oracle.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Cc: stable@vger.kernel.org
2022-05-26 10:50:49 -04:00
Julian Schroeder
fd5e363eac nfsd: destroy percpu stats counters after reply cache shutdown
Upon nfsd shutdown any pending DRC cache is freed. DRC cache use is
tracked via a percpu counter. In the current code the percpu counter
is destroyed before. If any pending cache is still present,
percpu_counter_add is called with a percpu counter==NULL. This causes
a kernel crash.
The solution is to destroy the percpu counter after the cache is freed.

Fixes: e567b98ce9 (“nfsd: protect concurrent access to nfsd stats counters”)
Signed-off-by: Julian Schroeder <jumaco@amazon.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2022-05-23 15:22:17 -04:00
Zhang Xiaoxu
6f6f84aa21 nfsd: Fix null-ptr-deref in nfsd_fill_super()
KASAN report null-ptr-deref as follows:

  BUG: KASAN: null-ptr-deref in nfsd_fill_super+0xc6/0xe0 [nfsd]
  Write of size 8 at addr 000000000000005d by task a.out/852

  CPU: 7 PID: 852 Comm: a.out Not tainted 5.18.0-rc7-dirty #66
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-1.fc33 04/01/2014
  Call Trace:
   <TASK>
   dump_stack_lvl+0x34/0x44
   kasan_report+0xab/0x120
   ? nfsd_mkdir+0x71/0x1c0 [nfsd]
   ? nfsd_fill_super+0xc6/0xe0 [nfsd]
   nfsd_fill_super+0xc6/0xe0 [nfsd]
   ? nfsd_mkdir+0x1c0/0x1c0 [nfsd]
   get_tree_keyed+0x8e/0x100
   vfs_get_tree+0x41/0xf0
   __do_sys_fsconfig+0x590/0x670
   ? fscontext_read+0x180/0x180
   ? anon_inode_getfd+0x4f/0x70
   do_syscall_64+0x35/0x80
   entry_SYSCALL_64_after_hwframe+0x44/0xae

This can be reproduce by concurrent operations:
	1. fsopen(nfsd)/fsconfig
	2. insmod/rmmod nfsd

Since the nfsd file system is registered before than nfsd_net allocated,
the caller may get the file_system_type and use the nfsd_net before it
allocated, then null-ptr-deref occurred.

So init_nfsd() should call register_filesystem() last.

Fixes: bd5ae9288d ("nfsd: register pernet ops last, unregister first")
Signed-off-by: Zhang Xiaoxu <zhangxiaoxu5@huawei.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2022-05-23 11:06:29 -04:00
Zhang Xiaoxu
62fdb65edb nfsd: Unregister the cld notifier when laundry_wq create failed
If laundry_wq create failed, the cld notifier should be unregistered.

Signed-off-by: Zhang Xiaoxu <zhangxiaoxu5@huawei.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2022-05-23 11:06:29 -04:00
Chuck Lever
28df098881 SUNRPC: Use RMW bitops in single-threaded hot paths
I noticed CPU pipeline stalls while using perf.

Once an svc thread is scheduled and executing an RPC, no other
processes will touch svc_rqst::rq_flags. Thus bus-locked atomics are
not needed outside the svc thread scheduler.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2022-05-23 11:06:29 -04:00
Chuck Lever
bb283ca18d NFSD: Clean up the show_nf_flags() macro
The flags are defined using C macros, so TRACE_DEFINE_ENUM is
unnecessary.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2022-05-23 11:06:29 -04:00
Chuck Lever
0122e88211 NFSD: Trace filecache opens
Instrument calls to nfsd_open_verified() to get a sense of the
filecache hit rate.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2022-05-23 11:06:29 -04:00
Chuck Lever
7e2ce0cc15 NFSD: Move documenting comment for nfsd4_process_open2()
Clean up nfsd4_open() by converting a large comment at the only
call site for nfsd4_process_open2() to a kerneldoc comment in
front of that function.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2022-05-23 11:06:29 -04:00
Chuck Lever
26320d7e31 NFSD: Fix whitespace
Clean up: Pull case arms back one tab stop to conform every other
switch statement in fs/nfsd/nfs4proc.c.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2022-05-23 11:06:29 -04:00
Chuck Lever
f67a16b147 NFSD: Remove dprintk call sites from tail of nfsd4_open()
Clean up: These relics are not likely to benefit server
administrators.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2022-05-23 11:06:29 -04:00
Chuck Lever
fb70bf124b NFSD: Instantiate a struct file when creating a regular NFSv4 file
There have been reports of races that cause NFSv4 OPEN(CREATE) to
return an error even though the requested file was created. NFSv4
does not provide a status code for this case.

To mitigate some of these problems, reorganize the NFSv4
OPEN(CREATE) logic to allocate resources before the file is actually
created, and open the new file while the parent directory is still
locked.

Two new APIs are added:

+ Add an API that works like nfsd_file_acquire() but does not open
the underlying file. The OPEN(CREATE) path can use this API when it
already has an open file.

+ Add an API that is kin to dentry_open(). NFSD needs to create a
file and grab an open "struct file *" atomically. The
alloc_empty_file() has to be done before the inode create. If it
fails (for example, because the NFS server has exceeded its
max_files limit), we avoid creating the file and can still return
an error to the NFS client.

BugLink: https://bugzilla.linux-nfs.org/show_bug.cgi?id=382
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Tested-by: JianHong Yin <jiyin@redhat.com>
2022-05-23 11:06:29 -04:00
Chuck Lever
f4d84c5264 NFSD: Clean up nfsd_open_verified()
Its only caller always passes S_IFREG as the @type parameter. As an
additional clean-up, add a kerneldoc comment.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2022-05-20 13:18:25 -04:00
Chuck Lever
1c388f2775 NFSD: Remove do_nfsd_create()
Now that its two callers have their own version-specific instance of
this function, do_nfsd_create() is no longer used.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2022-05-20 13:18:25 -04:00