linux-toradex.git/include/linux/sunrpc/cache.h, branch v5.12-rc8

sunrpc: fix duplicated word in

2020-09-21T14:21:10+00:00

Change "time time" to "time expiry_time" to match the field name.

Signed-off-by: Randy Dunlap 
Cc: "J. Bruce Fields" 
Cc: Chuck Lever 
Cc: Trond Myklebust 
Cc: Anna Schumaker 
Cc: linux-nfs@vger.kernel.org
Signed-off-by: Anna Schumaker

SUNRPC/cache: don't allow invalid entries to be flushed

2020-03-27T16:17:31+00:00

Trond points out in commit 277f27e2f277 ("SUNRPC/cache: Allow
garbage collection of invalid cache entries") that we allow invalid
cache entries to persist indefinitely. That fix, however,
reintroduces the problem fixed by Kinglong Mee's commit d6fc8821c2d2
("SUNRPC/Cache: Always treat the invalid cache as unexpired"), where
an invalid cache entry is immediately removed by a flush before
mountd responds to it. The result is that the server thread that
should be waiting for mountd to fill in that entry instead gets an
-ETIMEDOUT return from cache_check(). Symptoms are the server
becoming unresponsive after a restart, reproduceable by running
pynfs 4.1 test REBT5.

Instead, take a compromise approach: allow invalid cache entries to
be removed after they expire, but not to be removed by a cache
flush.

Fixes: 277f27e2f277 ("SUNRPC/cache: Allow garbage collection ... ")
Signed-off-by: J. Bruce Fields 
Signed-off-by: Chuck Lever

SUNRPC/cache: Allow garbage collection of invalid cache entries

2020-03-16T16:04:34+00:00

If the cache entry never gets initialised, we want the garbage
collector to be able to evict it. Otherwise if the upcall daemon
fails to initialise the entry, we end up never expiring it.

Signed-off-by: Trond Myklebust 
[ cel: resolved a merge conflict ]
Signed-off-by: Chuck Lever

nfsd: export upcalls must not return ESTALE when mountd is down

2020-03-16T16:04:33+00:00

If the rpc.mountd daemon goes down, then that should not cause all
exports to start failing with ESTALE errors. Let's explicitly
distinguish between the cache upcall cases that need to time out,
and those that do not.

Signed-off-by: Trond Myklebust 
Signed-off-by: Chuck Lever

nfs: use time64_t internally

2019-12-18T17:07:32+00:00

The timestamps for the cache are all in boottime seconds, so they
don't overflow 32-bit values, but the use of time_t is deprecated
because it generally does overflow when used with wall-clock time.

There are multiple possible ways of avoiding it:

- leave time_t, which is safe here, but forces others to
  look into this code to determine that it is over and over.

- use a more generic type, like 'int' or 'long', which is known
  to be sufficient here but loses the documentation of referring
  to timestamps

- use ktime_t everywhere, and convert into seconds in the few
  places where we want realtime-seconds. The conversion is
  sometimes expensive, but not more so than the conversion we
  do today.

- use time64_t to clarify that this code is safe. Nothing would
  change for 64-bit architectures, but it is slightly less
  efficient on 32-bit architectures.

Without a clear winner of the three approaches above, this picks
the last one, favouring readability over a small performance
loss on 32-bit architectures.

Signed-off-by: Arnd Bergmann

sunrpc: add a new cache_detail operation for when a cache is flushed

2019-08-19T15:00:39+00:00

When the exports table is changed, exportfs will usually write a new
time to the "flush" file in the nfsd.export cache procfile. This tells
the kernel to flush any entries that are older than that value.

This gives us a mechanism to tell whether an unexport might have
occurred. Add a new ->flush cache_detail operation that is called after
flushing the cache whenever someone writes to a "flush" file.

Signed-off-by: Jeff Layton 
Signed-off-by: Trond Myklebust 
Signed-off-by: Trond Myklebust 
Signed-off-by: J. Bruce Fields

SUNRPC: Track writers of the 'channel' file to improve cache_listeners_exist

2019-07-30T15:55:53+00:00

The sunrpc cache interface is susceptible to being fooled by a rogue
process just reading a 'channel' file.  If this happens the kernel
may think a valid daemon exists to service the cache when it does not.
For example, the following may fool the kernel:
cat /proc/net/rpc/auth.unix.gid/channel

Change the tracking of readers to writers when considering whether a
listener exists as all valid daemon processes either open a channel
file O_RDWR or O_WRONLY.  While this does not prevent a rogue process
from "stealing" a message from the kernel, it does at least improve
the kernels perception of whether a valid process servicing the cache
exists.

Signed-off-by: Dave Wysochanski 
Signed-off-by: J. Bruce Fields

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 363

2019-06-05T15:37:09+00:00

Based on 1 normalized pattern(s):

  released under terms in gpl version 2 see copying

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-only

has been chosen to replace the boilerplate/reference in 5 file(s).

Signed-off-by: Thomas Gleixner 
Reviewed-by: Armijn Hemel 
Reviewed-by: Allison Randal 
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190531081035.689962394@linutronix.de
Signed-off-by: Greg Kroah-Hartman

SUNRPC: Replace the cache_detail->hash_lock with a regular spinlock

2018-10-29T20:58:04+00:00

Now that the reader functions are all RCU protected, use a regular
spinlock rather than a reader/writer lock.

Signed-off-by: Trond Myklebust 
Signed-off-by: J. Bruce Fields

SUNRPC: Remove non-RCU protected lookup

2018-10-29T20:58:04+00:00

Clean up the cache code by removing the non-RCU protected lookup.

Signed-off-by: Trond Myklebust 
Signed-off-by: J. Bruce Fields