Being a hash table, hlist is the best option.
There is currently some ugliness were we treat "->next == NULL" as
a special case to avoid having to initialise the whole array.
This change nicely gets rid of that case.
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
The last_close field of a cache_detail is initialized to zero, so the
condition
detail->last_close < seconds_since_boot() - 30
may be false even for a cache that was never opened.
However, we want to immediately fail upcalls to caches that were never
opened: in the case of the auth_unix_gid cache, especially, which may
never be opened by mountd (if the --manage-gids option is not set), we
want to fail the upcall immediately. Otherwise client requests will be
dropped unnecessarily on reboot.
Also document these conditions.
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Attempt to make obvious the first-try-sleeping-then-try-deferral logic
by putting that logic into a top-level function that calls helpers.
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
The current practice of waiting for cache updates by queueing the
whole request to be retried has (at least) two problems.
1/ With NFSv4, requests can be quite complex and re-trying a whole
request when a later part fails should only be a last-resort, not a
normal practice.
2/ Large requests, and in particular any 'write' request, will not be
queued by the current code and doing so would be undesirable.
In many cases only a very sort wait is needed before the cache gets
valid data.
So, providing the underlying transport permits it by setting
->thread_wait,
arrange to wait briefly for an upcall to be completed (as reflected in
the clearing of CACHE_PENDING).
If the short wait was not long enough and CACHE_PENDING is still set,
fall back on the old approach.
The 'thread_wait' value is set to 5 seconds when there are spare
threads, and 1 second when there are no spare threads.
These values are probably much higher than needed, but will ensure
some forward progress.
Note that as we only request an update for a non-valid item, and as
non-valid items are updated in place it is extremely unlikely that
cache_check will return -ETIMEDOUT. Normally cache_defer_req will
sleep for a short while and then find that the item is_valid.
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
This protects us from confusion when the wallclock time changes.
We convert to and from wallclock when setting or reading expiry
times.
Also use seconds since boot for last_clost time.
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
This patch makes the cache_cleaner workqueue deferrable, to prevent
unnecessary system wake-ups, which is very important for embedded
battery-powered devices.
do_cache_clean() is called every 30 seconds at the moment, and often
makes the system wake up from its power-save sleep state. With this
change, when the workqueue uses a deferrable timer, the
do_cache_clean() invocation will be delayed and combined with the
closest "real" wake-up. This improves the power consumption situation.
Note, I tried to create a DECLARE_DELAYED_WORK_DEFERRABLE() helper
macro, similar to DECLARE_DELAYED_WORK(), but failed because of the
way the timer wheel core stores the deferrable flag (it is the
LSBit in the time->base pointer). My attempt to define a static
variable with this bit set ended up with the "initializer element is
not constant" error.
Thus, I have to use run-time initialization, so I created a new
cache_initialize() function which is called once when sunrpc is
being initialized.
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
* 'bkl/ioctl' of git://git.kernel.org/pub/scm/linux/kernel/git/frederic/random-tracing:
uml: Pushdown the bkl from harddog_kern ioctl
sunrpc: Pushdown the bkl from sunrpc cache ioctl
sunrpc: Pushdown the bkl from ioctl
autofs4: Pushdown the bkl from ioctl
uml: Convert to unlocked_ioctls to remove implicit BKL
ncpfs: BKL ioctl pushdown
coda: Clean-up whitespace problems in pioctl.c
coda: BKL ioctl pushdown
drivers: Push down BKL into various drivers
isdn: Push down BKL into ioctl functions
scsi: Push down BKL into ioctl functions
dvb: Push down BKL into ioctl functions
smbfs: Push down BKL into ioctl function
coda/psdev: Remove BKL from ioctl function
um/mmapper: Remove BKL usage
sn_hwperf: Kill BKL usage
hfsplus: Push down BKL into ioctl function
* 'for-2.6.35' of git://linux-nfs.org/~bfields/linux: (45 commits)
Revert "nfsd4: distinguish expired from stale stateids"
nfsd: safer initialization order in find_file()
nfs4: minor callback code simplification, comment
NFSD: don't report compiled-out versions as present
nfsd4: implement reclaim_complete
nfsd4: nfsd4_destroy_session must set callback client under the state lock
nfsd4: keep a reference count on client while in use
nfsd4: mark_client_expired
nfsd4: introduce nfs4_client.cl_refcount
nfsd4: refactor expire_client
nfsd4: extend the client_lock to cover cl_lru
nfsd4: use list_move in move_to_confirmed
nfsd4: fold release_session into expire_client
nfsd4: rename sessionid_lock to client_lock
nfsd4: fix bare destroy_session null dereference
nfsd4: use local variable in nfs4svc_encode_compoundres
nfsd: further comment typos
sunrpc: centralise most calls to svc_xprt_received
nfsd4: fix unlikely race in session replay case
nfsd4: fix filehandle comment
...
Now that cache_ioctl_procfs() calls the bkl explicitly, we need to
include the relevant header as well.
This fixes the following build error:
net/sunrpc/cache.c: In function 'cache_ioctl_procfs':
net/sunrpc/cache.c:1355: error: implicit declaration of function 'lock_kernel'
net/sunrpc/cache.c:1359: error: implicit declaration of function 'unlock_kernel'
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Push down the bkl from procfs's ioctl main handler to its users.
Only three procfs users implement an ioctl (non unlocked) handler.
Turn them into unlocked_ioctl and push down the Devil inside.
v2: PDE(inode)->data doesn't need to be under bkl
v3: And don't forget to git-add the result
v4: Use wrappers to pushdown instead of an invasive and error prone
handlers surgery.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: John Kacur <jkacur@redhat.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
If sunrpc_cache_lookup finds an expired entry, remove it from
the cache and return a freshly created non-VALID entry instead.
This ensures that we only ever get a usable entry, or an
entry that will become usable once an update arrives.
i.e. we will never need to repeat the lookup.
This allows us to remove the 'is_expired' test from cache_check
(i.e. from cache_is_valid). cache_check should never get an expired
entry as 'lookup' will never return one. If it does happen - due to
inconvenient timing - then just accept it as still valid, it won't be
very much past it's use-by date.
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
This removes a tiny bit of code duplication, but more important
prepares for following patch which will perform the expiry check in
cache_lookup and the rest of the validity check in cache_check.
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
currently expired entries remain in the auth caches as long
as there is a reference.
This was needed long ago when the auth_domain cache used the same
cache infrastructure. But since that (being a very different sort
of cache) was separated, this test is no longer needed.
So remove the test on refcnt and tidy up the surrounding code.
This allows the cache_dequeue call (which needed to be there to
drop a potentially awkward reference) can be moved outside of the
spinlock which is a better place for it.
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
Not including net/atm/
Compiled tested x86 allyesconfig only
Added a > 80 column line or two, which I ignored.
Existing checkpatch plaints willfully, cheerfully ignored.
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
In cache_defer_req, 'dreq' is used for two significantly different
values that happen to be of the same type.
This is both confusing, and makes it hard to extend the range of one of
the values as we will in the next patch.
So introduce 'discard' to take one of the values.
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
Using list_del_init is generally safer than list_del, and it will
allow us, in a subsequent patch, to see if an entry has already been
processed or not.
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
The extra call to cache_revisit_request in cache_fresh_unlocked is not
needed, as should have been fairly clear at the time of
commit 4013edea9a
If there are requests to be revisited, then we can be sure that
CACHE_PENDING is set, so the second call is sufficient.
So remove the first call.
Then remove the 'new' parameter,
then remove the return value for cache_fresh_locked which is only used
to provide the value for 'new'.
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
As "cache_defer_req" does not sound like a predicate, having it return
a boolean value can be confusing. It is more consistent to return
0 for success and negative for error.
Exactly what error code to return is not important as we don't
differentiate between reasons why the request wasn't deferred,
we only care about whether it was deferred or not.
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
Otherwise we Oops if the module containing the cache detail is removed
before all cache readers have closed the file.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
NeilBrown
J. Bruce Fields
Andrea Gelmini
Artem Bityutskiy
Linus Torvalds
Frederic Weisbecker
Li Zefan
Joe Perches
J. Bruce Fields
Trond Myklebust