Improve observability of backchannel session operation.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Add a trace point that records SEQ4_STATUS flags returned in an
NFSv4.1 SEQUENCE response. SEQ4_STATUS flags report backchannel
issues and changes to lease state to clients. Knowing what the
server is reporting to clients is useful for debugging both
configuration and operational issues in real time.
For example, upcoming patches will enable server administrators to
revoke parts of a client's lease; that revocation is indicated to
the client when a subsequent SEQUENCE operation has one or more
SEQ4_STATUS flags that are set.
Sample trace records:
nfsd-927 [006] 615.581821: nfsd_seq4_status: xid=0x095ded07 sessionid=65a032c3:b7845faf:00000001:00000000 status_flags=BACKCHANNEL_FAULT
nfsd-927 [006] 615.588043: nfsd_seq4_status: xid=0x0a5ded07 sessionid=65a032c3:b7845faf:00000001:00000000 status_flags=BACKCHANNEL_FAULT
nfsd-928 [003] 615.588448: nfsd_seq4_status: xid=0x0b5ded07 sessionid=65a032c3:b7845faf:00000001:00000000 status_flags=BACKCHANNEL_FAULT
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
This trace point was for debugging the DRC's garbage collection. In
the field it's just noise.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Add trace points on destination server to track inter and intra
server copy operations.
Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
Tested-by: Chen Hanxiao <chenhx.fnst@fujitsu.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
The svc_ prefix is identified with the SunRPC layer. Although the
duplicate reply cache caches RPC replies, it is only for the NFS
protocol. Rename the struct to better reflect its purpose.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Enable nfsd_prune_bucket() to drop the bucket lock while calling
kfree(). Use the same pattern that Jeff recently introduced in the
NFSD filecache.
A few percpu operations are moved outside the lock since they
temporarily disable local IRQs which is expensive and does not
need to be done while the lock is held.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
This patch grants write delegations for OPEN with NFS4_SHARE_ACCESS_WRITE
if there is no conflict with other OPENs.
Write delegation conflicts with another OPEN, REMOVE, RENAME and SETATTR
are handled the same as read delegation using notify_change,
try_break_deleg.
The NFSv4.0 protocol does not enable a server to determine that a
conflicting GETATTR originated from the client holding the
delegation versus coming from some other client. With NFSv4.1 and
later, the SEQUENCE operation that begins each COMPOUND contains a
client ID, so delegation recall can be safely squelched in this case.
With NFSv4.0, however, the server must recall or send a CB_GETATTR
(per RFC 7530 Section 16.7.5) even when the GETATTR originates from
the client holding that delegation.
An NFSv4.0 client can trigger a pathological situation if it always
sends a DELEGRETURN preceded by a conflicting GETATTR in the same
COMPOUND. COMPOUND execution will always stop at the GETATTR and the
DELEGRETURN will never get executed. The server eventually revokes
the delegation, which can result in loss of open or lock state.
Tracepoint added to track whether read or write delegation is granted.
Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Add trace log eye-catchers that record the arguments used to
configure NFSD. This helps when troubleshooting the NFSD
administrative interfaces.
These tracepoints can capture NFSD start-up and shutdown times and
parameters, changes in lease time and thread count, and a request
to end the namespace's NFSv4 grace period, in addition to the set
of NFS versions that are enabled.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Instead of open coding a __dynamic_array(), use the __string() and
__assign_str() helper macros that exist for this kind of use case.
Part of an effort to remove deprecated strlcpy() [1] completely from the
kernel[2].
[1] https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy
[2] https://github.com/KSPP/linux/issues/89
Fixes: 3c92fba557 ("NFSD: Enhance the nfsd_cb_setup tracepoint")
Signed-off-by: Azeem Shaikh <azeemshaikh38@gmail.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Most of the time, NFSv4 clients issue a COMMIT before the final CLOSE of
an open stateid, so with NFSv4, the fsync in the nfsd_file_free path is
usually a no-op and doesn't block.
We have a customer running knfsd over very slow storage (XFS over Ceph
RBD). They were using the "async" export option because performance was
more important than data integrity for this application. That export
option turns NFSv4 COMMIT calls into no-ops. Due to the fsync in this
codepath however, their final CLOSE calls would still stall (since a
CLOSE effectively became a COMMIT).
I think this fsync is not strictly necessary. We only use that result to
reset the write verifier. Instead of fsync'ing all of the data when we
free an nfsd_file, we can just check for writeback errors when one is
acquired and when it is freed.
If the client never comes back, then it'll never see the error anyway
and there is no point in resetting it. If an error occurs after the
nfsd_file is removed from the cache but before the inode is evicted,
then it will reset the write verifier on the next nfsd_file_acquire,
(since there will be an unseen error).
The only exception here is if something else opens and fsyncs the file
during that window. Given that local applications work with this
limitation today, I don't see that as an issue.
Link: https://bugzilla.redhat.com/show_bug.cgi?id=2166658
Fixes: ac3a2585f0 ("nfsd: rework refcounting in filecache")
Reported-and-tested-by: Pierguido Lambri <plambri@redhat.com>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Commit fb70bf124b ("NFSD: Instantiate a struct file when creating a
regular NFSv4 file") added the ability to cache an open fd over a
compound. There are a couple of problems with the way this currently
works:
It's racy, as a newly-created nfsd_file can end up with its PENDING bit
cleared while the nf is hashed, and the nf_file pointer is still zeroed
out. Other tasks can find it in this state and they expect to see a
valid nf_file, and can oops if nf_file is NULL.
Also, there is no guarantee that we'll end up creating a new nfsd_file
if one is already in the hash. If an extant entry is in the hash with a
valid nf_file, nfs4_get_vfs_file will clobber its nf_file pointer with
the value of op_file and the old nf_file will leak.
Fix both issues by making a new nfsd_file_acquirei_opened variant that
takes an optional file pointer. If one is present when this is called,
we'll take a new reference to it instead of trying to open the file. If
the nfsd_file already has a valid nf_file, we'll just ignore the
optional file and pass the nfsd_file back as-is.
Also rework the tracepoints a bit to allow for an "opened" variant and
don't try to avoid counting acquisitions in the case where we already
have a cached open file.
Fixes: fb70bf124b ("NFSD: Instantiate a struct file when creating a regular NFSv4 file")
Cc: Trond Myklebust <trondmy@hammerspace.com>
Reported-by: Stanislav Saner <ssaner@redhat.com>
Reported-and-Tested-by: Ruben Vestergaard <rubenv@drcmr.dk>
Reported-and-Tested-by: Torkil Svensgaard <torkil@drcmr.dk>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
The filecache refcounting is a bit non-standard for something searchable
by RCU, in that we maintain a sentinel reference while it's hashed. This
in turn requires that we have to do things differently in the "put"
depending on whether its hashed, which we believe to have led to races.
There are other problems in here too. nfsd_file_close_inode_sync can end
up freeing an nfsd_file while there are still outstanding references to
it, and there are a number of subtle ToC/ToU races.
Rework the code so that the refcount is what drives the lifecycle. When
the refcount goes to zero, then unhash and rcu free the object. A task
searching for a nfsd_file is allowed to bump its refcount, but only if
it's not already 0. Ensure that we don't make any other changes to it
until a reference is held.
With this change, the LRU carries a reference. Take special care to deal
with it when removing an entry from the list, and ensure that we only
repurpose the nf_lru list_head when the refcount is 0 to ensure
exclusive access to it.
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Add tracepoints to trace start and end of CB_RECALL_ANY operation.
Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
[ cel: added show_rca_mask() macro ]
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
In a coming patch, we're going to rework how the filecache refcounting
works. Move some code around in the function to reduce the churn in the
later patches, and rename some of the functions with (hopefully) clearer
names: nfsd_file_flush becomes nfsd_file_fsync, and
nfsd_file_unhash_and_dispose is renamed to nfsd_file_unhash_and_queue.
Also, the nfsd_file_put_final tracepoint is renamed to nfsd_file_free,
to better match the name of the function from which it's called.
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: NeilBrown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Delegation revocation is an exceptional event that is not otherwise
visible externally (eg, no network traffic is emitted). Generate a
trace record when it occurs so that revocation can be observed or
other activity can be triggered. Example:
nfsd-1104 [005] 1912.002544: nfsd_stid_revoke: client 633c9343:4e82788d stateid 00000003:00000001 ref=2 type=DELEG
Trace infrastructure is provided for subsequent additional tracing
related to nfs4_stid activity.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Tested-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Handing out a delegation stateid is recorded with the
nfsd_deleg_read tracepoint, but there isn't a matching tracepoint
for recording when the stateid is returned.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
NFSv4 operations manage the lifetime of nfsd_file items they use by
means of NFSv4 OPEN and CLOSE. Hence there's no need for them to be
garbage collected.
Introduce a mechanism to enable garbage collection for nfsd_file
items used only by NFSv2/3 callers.
Note that the change in nfsd_file_put() ensures that both CLOSE and
DELEGRETURN will actually close out and free an nfsd_file on last
reference of a non-garbage-collected file.
Link: https://bugzilla.linux-nfs.org/show_bug.cgi?id=394
Suggested-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Tested-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: NeilBrown <neilb@suse.de>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Now that the nfsd_fh_verify_err() tracepoint is always called on
error, it needs to handle cases where the filehandle is not yet
fully formed.
Fixes: 93c128e709 ("nfsd: ensure we always call fh_verify_error tracepoint")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Subsequent patches will use this mechanism to wake up an operation
that is waiting for a client to return a delegation.
The new tracepoint records whether the wait timed out or was
properly awoken by the expected DELEGRETURN:
nfsd-1155 [002] 83799.493199: nfsd_delegret_wakeup: xid=0x14b7d6ef fh_hash=0xf6826792 (timed out)
Suggested-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Wireshark has always been lousy about dissecting NFSv4 callbacks,
especially NFSv4.0 backchannel requests. Add tracepoints so we
can surgically capture these events in the trace log.
Tracepoints are time-stamped and ordered so that we can now observe
the timing relationship between a CB_RECALL Reply and the client's
DELEGRETURN Call. Example:
nfsd-1153 [002] 211.986391: nfsd_cb_recall: addr=192.168.1.67:45767 client 62ea82e4:fee7492a stateid 00000003:00000001
nfsd-1153 [002] 212.095634: nfsd_compound: xid=0x0000002c opcnt=2
nfsd-1153 [002] 212.095647: nfsd_compound_status: op=1/2 OP_PUTFH status=0
nfsd-1153 [002] 212.095658: nfsd_file_put: hash=0xf72 inode=0xffff9291148c7410 ref=3 flags=HASHED|REFERENCED may=READ file=0xffff929103b3ea00
nfsd-1153 [002] 212.095661: nfsd_compound_status: op=2/2 OP_DELEGRETURN status=0
kworker/u25:8-148 [002] 212.096713: nfsd_cb_recall_done: client 62ea82e4:fee7492a stateid 00000003:00000001 status=0
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
The Linux NFSv4 client implementation does not use COMPOUND tags,
but the Solaris and MacOS implementations do, and so does pynfs.
Record these eye-catchers in the server's trace buffer to annotate
client requests while troubleshooting.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Record permission errors in the trace log. Note that the new trace
event is conditional, so it will only record non-zero return values
from nfsd_permission().
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Avoid recording the allocation of an nfsd_file item that is
immediately released because a matching item was already
inserted in the hash.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
These tracepoints collect different information: the create case does
not open a file, so there's no nf_file available.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Enable the filecache hash table to start small, then grow with the
workload. Smaller server deployments benefit because there should
be lower memory utilization. Larger server deployments should see
improved scaling with the number of open files.
Suggested-by: Jeff Layton <jlayton@kernel.org>
Suggested-by: Dave Chinner <david@fromorbit.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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>
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>
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>
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>
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>
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>
Clean up.
The PROC_ARGS macros were added when I thought that NFSD tracepoints
would be reporting endpoint information. However, tracepoints in the
RPC server now report transport endpoint information, so in general
there's no need for the upper layers to do that any more, and these
macros can be retired.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
NFSv3 and NFSv4 use u64 offset values on the wire. Record these values
verbatim without the implicit type case to loff_t.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
According to commit bbf2f09883 ("nfsd: Reset the boot verifier on
all write I/O errors"), the Linux NFS server forces all clients to
resend pending unstable writes if any server-side write or commit
operation encounters an error (say, ENOSPC). This is a rare and
quite exceptional event that could require administrative recovery
action, so it should be made trace-able. Example trace event:
nfsd-938 [002] 7174.945558: nfsd_writeverf_reset: boot_time= 61cc920d xid=0xdcd62036 error=-28 new verifier=0x08aecc6142515904
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Since a clone error commit can cause the boot verifier to change,
we should trace those errors.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
[ cel: Addressed a checkpatch.pl splat in fs/nfsd/vfs.h ]
Clean up: The garbage_args and cant_encode tracepoints report the
same information as each other, so combine them into a single
tracepoint class to reduce code duplication and slightly reduce the
size of trace.o.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Refactor: surface useful show_ macros so they can be shared between
the client and server trace code.
Additional clean up:
- Housekeeping: ensure the correct #include files are pulled in
and add proper TRACE_DEFINE_ENUM where they are missing
- Use a consistent naming scheme for the helpers
- Store values to be displayed symbolically as unsigned long, as
that is the type that the __print_yada() functions take
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
The double copy of the string is a mistake, plus __assign_str()
uses strlen(), which is wrong to do on a string that isn't
guaranteed to be NUL-terminated.
Fixes: 6019ce0742 ("NFSD: Add a tracepoint to record directory entry encoding")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Clean-up: Re-order the display of IP address and client ID to be
consistent with other _cb_ tracepoints.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Clean up: These are noise in properly working systems. If you really
need to observe the operation of the callback mechanism, use the
sunrpc:rpc\* tracepoints along with the workqueue tracepoints.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Record a tracepoint event when the server performs a callback
probe. This event can be enabled as a group with other nfsd_cb
tracepoints.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Renamed so it can be enabled as a set with the other nfsd_cb_
tracepoints. And, consistent with those tracepoints, report the
address of the client, the client ID the server has given it, and
the state ID being recalled.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
