linux.git/net/sunrpc/cache.c, branch v5.15

SUNRPC: improve error response to over-size gss credential

2021-09-03T17:38:11+00:00

When the NFS server receives a large gss (kerberos) credential and tries
to pass it up to rpc.svcgssd (which is deprecated), it triggers an
infinite loop in cache_read().

cache_request() always returns -EAGAIN, and this causes a "goto again".

This patch:
 - changes the error to -E2BIG to avoid the infinite loop, and
 - generates a WARN_ONCE when rsi_request first sees an over-sized
   credential.  The warning suggests switching to gssproxy.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=196583
Signed-off-by: NeilBrown 
Signed-off-by: Chuck Lever

sunrpc: clean-up cache downcall

2020-12-09T14:38:34+00:00

We can simplify code around cache_downcall unifying memory
allocations using kvmalloc. This has the benefit of getting rid of
cache_slow_downcall (and queue_io_mutex), and also matches userland
allocation size and limits.

Signed-off-by: Roberto Bergantinos Corpas 
Signed-off-by: Chuck Lever

sunrpc: raise kernel RPC channel buffer size

2020-10-20T17:21:30+00:00

Its possible that using AUTH_SYS and mountd manage-gids option a
user may hit the 8k RPC channel buffer limit. This have been observed
on field, causing unanswered RPCs on clients after mountd fails to
write on channel :

rpc.mountd[11231]: auth_unix_gid: error writing reply

Userland nfs-utils uses a buffer size of 32k (RPC_CHAN_BUF_SIZE), so
lets match those two.

Signed-off-by: Roberto Bergantinos Corpas 
Signed-off-by: J. Bruce Fields

sunrpc: simplify do_cache_clean

2020-09-25T22:02:02+00:00

Is it just me, or is the logic written in a slightly convoluted way?

I find it a little easier to read this way.

Signed-off-by: J. Bruce Fields

sunrpc: cache : Replace seq_printf with seq_puts

2020-09-25T22:01:28+00:00

seq_puts is a lot cheaper than seq_printf, so use that to print
literal strings.

Signed-off-by: Xu Wang 
Signed-off-by: J. Bruce Fields

SUNRPC/cache: Fix unsafe traverse caused double-free in cache_purge

2020-04-13T14:28:21+00:00

Deleting list entry within hlist_for_each_entry_safe is not safe unless
next pointer (tmp) is protected too. It's not, because once hash_lock
is released, cache_clean may delete the entry that tmp points to. Then
cache_purge can walk to a deleted entry and tries to double free it.

Fix this bug by holding only the deleted entry's reference.

Suggested-by: NeilBrown 
Signed-off-by: Yihao Wu 
Reviewed-by: NeilBrown 
[ cel: removed unused variable ]
Signed-off-by: Chuck Lever

sunrpc: Add tracing for cache events

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

Add basic tracing for debugging the sunrpc cache events.

Signed-off-by: Trond Myklebust 
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

sunrpc: Pass lockdep expression to RCU lists

2020-03-16T16:04:31+00:00

detail->hash_table[] is traversed using hlist_for_each_entry_rcu
outside an RCU read-side critical section but under the protection
of detail->hash_lock.

Hence, add corresponding lockdep expression to silence false-positive
warnings, and harden RCU lists.

Signed-off-by: Amol Grover 
Signed-off-by: J. Bruce Fields 
Signed-off-by: Chuck Lever