The @src parameter is sometimes a pointer to a struct nfsd_file and
sometimes a pointer to struct file hiding in a phony struct
nfsd_file. Refactor nfsd4_cleanup_inter_ssc() so the @src parameter
is always an explicit struct file.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Pack the fields to reduce the size of struct nfsd4_op, which is used
an array in struct nfsd4_compoundargs.
sizeof(struct nfsd4_op):
Before: /* size: 672, cachelines: 11, members: 5 */
After: /* size: 640, cachelines: 10, members: 5 */
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
In function ‘strncpy’,
inlined from ‘nfsd4_ssc_setup_dul’ at /home/cel/src/linux/manet/fs/nfsd/nfs4proc.c:1392:3,
inlined from ‘nfsd4_interssc_connect’ at /home/cel/src/linux/manet/fs/nfsd/nfs4proc.c:1489:11:
/home/cel/src/linux/manet/include/linux/fortify-string.h:52:33: warning: ‘__builtin_strncpy’ specified bound 63 equals destination size [-Wstringop-truncation]
52 | #define __underlying_strncpy __builtin_strncpy
| ^
/home/cel/src/linux/manet/include/linux/fortify-string.h:89:16: note: in expansion of macro ‘__underlying_strncpy’
89 | return __underlying_strncpy(p, q, size);
| ^~~~~~~~~~~~~~~~~~~~
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Similar changes to nfsd4_encode_readv(), all bundled into a single
patch.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Clean up: Use a helper instead of open-coding the calculation of
the XDR pad size.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Clean-up: Now that nfsd4_encode_readv() does not have to encode the
EOF or rd_length values, it no longer needs to subtract 8 from
@starting_len.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
write_bytes_to_xdr_buf() is pretty expensive to use for inserting
an XDR data item that is always 1 XDR_UNIT at an address that is
always XDR word-aligned.
Since both the readv and splice read paths encode EOF and maxcount
values, move both to a common code path.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Refactor: Make the EOF result available in the entire NFSv4 READ
path.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Do the test_bit() once -- this reduces the number of locked-bus
operations and makes the function a little easier to read.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
write_bytes_to_xdr_buf() is a generic way to place a variable-length
data item in an already-reserved spot in the encoding buffer.
However, it is costly. In nfsd4_encode_fattr(), it is unnecessary
because the data item is fixed in size and the buffer destination
address is always word-aligned.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
write_bytes_to_xdr_buf() is a generic way to place a variable-length
data item in an already-reserved spot in the encoding buffer.
However, it is costly, and here, it is unnecessary because the
data item is fixed in size, the buffer destination address is
always word-aligned, and the destination location is already in
@p.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
This printk pops every time nfsd.ko gets plugged in. Most kmods don't do
that and this one is not very informative. Olaf's email address seems to
be defunct at this point anyway. Just drop it.
Cc: Olaf Kirch <okir@suse.com>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Currently there is no limit on how many v4 clients are supported
by the system. This can be a problem in systems with small memory
configuration to function properly when a very large number of
clients exist that creates memory shortage conditions.
This patch enforces a limit of 1024 NFSv4 clients, including courtesy
clients, per 1GB of system memory. When the number of the clients
reaches the limit, requests that create new clients are returned
with NFS4ERR_DELAY and the laundromat is kicked start to trim old
clients. Due to the overhead of the upcall to remove the client
record, the maximun number of clients the laundromat removes on
each run is limited to 128. This is done to ensure the laundromat
can still process the other tasks in a timely manner.
Since there is now a limit of the number of clients, the 24-hr
idle time limit of courtesy client is no longer needed and was
removed.
Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Add counter nfs4_client_count to keep track of the total number
of v4 clients, including courtesy clients, in the system.
Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
This patch moves the v4 specific code from nfsd_init_net() to
nfsd4_init_leases_net() helper in nfs4state.c
Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
The documenting comment for struct nf_file states:
/*
* A representation of a file that has been opened by knfsd. These are hashed
* in the hashtable by inode pointer value. Note that this object doesn't
* hold a reference to the inode by itself, so the nf_inode pointer should
* never be dereferenced, only used for comparison.
*/
Replace the two existing dereferences to make the comment always
true.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
The last close of a file should enable other accessors to open and
use that file immediately. Leaving the file open in the filecache
prevents other users from accessing that file until the filecache
garbage-collects the file -- sometimes that takes several seconds.
Reported-by: Wang Yugui <wangyugui@e16-tech.com>
Link: https://bugzilla.linux-nfs.org/show_bug.cgi?387
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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>
Add code to initialize and tear down an rhashtable. The rhashtable
is not used yet.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
In a moment, the nfsd_file_hashtbl global will be replaced with an
rhashtable. Replace the one or two spots that need to check if the
hash table is available. We can easily reuse the SHUTDOWN flag for
this purpose.
Document that this mechanism relies on callers to hold the
nfsd_mutex to prevent init, shutdown, and purging to run
concurrently.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
The value in this field can always be computed from nf_inode, thus
it is no longer used.
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
