IF YOU WOULD LIKE TO GET AN ACCOUNT, please write an
email to Administrator. User accounts are meant only to access repo
and report issues and/or generate pull requests.
This is a purpose-specific Git hosting for
BaseALT
projects. Thank you for your understanding!
Только зарегистрированные пользователи имеют доступ к сервису!
Для получения аккаунта, обратитесь к администратору.
If the GETATTR request on a file that has write delegation in effect and
the request attributes include the change info and size attribute then
the write delegation is recalled. If the delegation is returned within
30ms then the GETATTR is serviced as normal otherwise the NFS4ERR_DELAY
error is returned for the GETATTR.
Add counter for write delegation recall due to conflict GETATTR. This is
used to evaluate the need to implement CB_GETATTR to adoid recalling the
delegation with conflit GETATTR.
Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
We're not doing any blocking operations for OP_OFFLOAD_STATUS, so taking
and putting a reference is a waste of effort. Take the client lock,
search for the copy and fetch the wr_bytes_written field and return.
Also, make find_async_copy a static function.
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Olga Kornievskaia <kolga@netapp.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
The delegation reaper is called by nfsd memory shrinker's on
the 'count' callback. It scans the client list and sends the
courtesy CB_RECALL_ANY to the clients that hold delegations.
To avoid flooding the clients with CB_RECALL_ANY requests, the
delegation reaper sends only one CB_RECALL_ANY request to each
client per 5 seconds.
Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
[ cel: moved definition of RCA4_TYPE_MASK_RDATA_DLG ]
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
fh_match() is costly, especially when filehandles are large (as is
the case for NFSv4). It needs to be used sparingly when searching
data structures. Unfortunately, with common workloads, I see
multiple thousands of objects stored in file_hashtbl[], which has
just 256 buckets, making its bucket hash chains quite lengthy.
Walking long hash chains with the state_lock held blocks other
activity that needs that lock. Sizable hash chains are a common
occurrance once the server has handed out some delegations, for
example -- IIUC, each delegated file is held open on the server by
an nfs4_file object.
To help mitigate the cost of searching with fh_match(), replace the
nfs4_file hash table with an rhashtable, which can dynamically
resize its bucket array to minimize hash chain length.
The result of this modification is an improvement in the latency of
NFSv4 operations, and the reduction of nfsd CPU utilization due to
eliminating the cost of multiple calls to fh_match() and reducing
the CPU cache misses incurred while walking long hash chains in the
nfs4_file hash table.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: NeilBrown <neilb@suse.de>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
queue_work can return false and not queue anything, if the work is
already queued. If that happens in the case of a CB_RECALL, we'll have
taken an extra reference to the stid that will never be put. Ensure we
throw a warning in that case.
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Code maintenance: The name of the copy_stateid_t::sc_count field
collides with the sc_count field in struct nfs4_stid, making the
latter difficult to grep for when auditing stateid reference
counting.
No behavior change expected.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
nfsd4_prepare_cb_recall() has been removed since
commit 0162ac2b97 ("nfsd: introduce nfsd4_callback_ops"),
so remove it.
Signed-off-by: Gaosheng Cui <cuigaosheng1@huawei.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
When attempting an NFSv4 mount, a Solaris NFSv4 client builds a
single large COMPOUND that chains a series of LOOKUPs to get to the
pseudo filesystem root directory that is to be mounted. The Linux
NFS server's current maximum of 16 operations per NFSv4 COMPOUND is
not large enough to ensure that this works for paths that are more
than a few components deep.
Since NFSD_MAX_OPS_PER_COMPOUND is mostly a sanity check, and most
NFSv4 COMPOUNDS are between 3 and 6 operations (thus they do not
trigger any re-allocation of the operation array on the server),
increasing this maximum should result in little to no impact.
The ops array can get large now, so allocate it via vmalloc() to
help ensure memory fragmentation won't cause an allocation failure.
Link: https://bugzilla.kernel.org/show_bug.cgi?id=216383
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
This patch provides courteous server support for delegation only.
Only expired client with delegation but no conflict and no open
or lock state is allowed to be in COURTESY state.
Delegation conflict with COURTESY/EXPIRABLE client is resolved by
setting it to EXPIRABLE, queue work for the laundromat and return
delay to the caller. Conflict is resolved when the laudromat runs
and expires the EXIRABLE client while the NFS client retries the
OPEN request. Local thread request that gets conflict is doing the
retry in _break_lease.
Client in COURTESY or EXPIRABLE state is allowed to reconnect and
continues to have access to its state. Access to the nfs4_client by
the reconnecting thread and the laundromat is serialized via the
client_lock.
Reviewed-by: J. Bruce Fields <bfields@fieldses.org>
Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
nbl allocated in nfsd4_lock can be released by a several ways:
directly in nfsd4_lock(), via nfs4_laundromat(), via another nfs
command RELEASE_LOCKOWNER or via nfsd4_callback.
This structure should be refcounted to be used and released correctly
in all these cases.
Refcount is initialized to 1 during allocation and is incremented
when nbl is added into nbl_list/nbl_lru lists.
Usually nbl is linked into both lists together, so only one refcount
is used for both lists.
However nfsd4_lock() should keep in mind that nbl can be present
in one of lists only. This can happen if nbl was handled already
by nfs4_laundromat/nfsd4_callback/etc.
Refcount is decremented if vfs_lock_file() returns FILE_LOCK_DEFERRED,
because nbl can be handled already by nfs4_laundromat/nfsd4_callback/etc.
Refcount is not changed in find_blocked_lock() because of it reuses counter
released after removing nbl from lists.
Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
The use of the bitmaps is confusing. Add a cross-reference to make it
easier to find the existing comment. Add an updated reference with URL
to make it quicker to look up. And a bit more editorializing about the
value of this.
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
It's unusual but possible for multiple filehandles to point to the same
file. In that case, we may end up with multiple nfs4_files referencing
the same inode.
For delegation purposes it will turn out to be useful to flag those
cases.
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
The nfs4_file structure is per-filehandle, not per-inode, because the
spec requires open and other state to be per filehandle.
But it will turn out to be convenient for nfs4_files associated with the
same inode to be hashed to the same bucket, so let's hash on the inode
instead of the filehandle.
Filehandle aliasing is rare, so that shouldn't have much performance
impact.
(If you have a ton of exported filesystems, though, and all of them have
a root with inode number 2, could that get you an overlong hash chain?
Perhaps this (and the v4 open file cache) should be hashed on the inode
pointer instead.)
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
mountd can now monitor clients appearing and disappearing in
/proc/fs/nfsd/clients, and will log these events, in liu of the logging
of mount/unmount events for NFSv3.
Currently it cannot distinguish between unconfirmed clients (which might
be transient and totally uninteresting) and confirmed clients.
So add a "status: " line which reports either "confirmed" or
"unconfirmed", and use fsnotify to report that the info file
has been modified.
This requires a bit of infrastructure to keep the dentry for the "info"
file. There is no need to take a counted reference as the dentry must
remain around until the client is removed.
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
The set_client() was already taken care of by process_open1().
The comments here are mostly redundant with the code.
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
It was an interesting idea but nobody seems to be using it, it's buggy
at this point, and nfs4state.c is already complicated enough without it.
The new nfsd/clients/ code provides some of the same functionality, and
could probably do more if desired.
This feature has been deprecated since 9d60d93198 ("Deprecate nfsd
fault injection").
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Capture obvious events and replace dprintk() call sites. Introduce
infrastructure so that adding more tracepoints in this code later
is simplified.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
A couple of time_t variables are only used to track the state of the
lease time and its expiration. The code correctly uses the 'time_after()'
macro to make this work on 32-bit architectures even beyond year 2038,
but the get_seconds() function and the time_t type itself are deprecated
as they behave inconsistently between 32-bit and 64-bit architectures
and often lead to code that is not y2038 safe.
As a minor issue, using get_seconds() leads to problems with concurrent
settimeofday() or clock_settime() calls, in the worst case timeout never
triggering after the time has been set backwards.
Change nfsd to use time64_t and ktime_get_boottime_seconds() here. This
is clearly excessive, as boottime by itself means we never go beyond 32
bits, but it does mean we handle this correctly and consistently without
having to worry about corner cases and should be no more expensive than
the previous implementation on 64-bit architectures.
The max_cb_time() function gets changed in order to avoid an expensive
64-bit division operation, but as the lease time is at most one hour,
there is no change in behavior.
Also do the same for server-to-server copy expiration time.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
[bfields@redhat.com: fix up copy expiration]
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
The nfsd4_blocked_lock->nbl_time timestamp is recorded in jiffies,
but then compared to a CLOCK_REALTIME timestamp later on, which makes
no sense.
For consistency with the other timestamps, change this to use a time_t.
This is a change in behavior, which may cause regressions, but the
current code is not sensible. On a system with CONFIG_HZ=1000,
the 'time_after((unsigned long)nbl->nbl_time, (unsigned long)cutoff))'
check is false for roughly the first 18 days of uptime and then true
for the next 49 days.
Fixes: 7919d0a27f ("nfsd: add a LRU list for blocked locks")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
The nii_time field gets truncated to 'time_t' on 32-bit architectures
before printing.
Remove the use of 'struct timespec' to product the correct output
beyond 2038.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Given a universal address, mount the source server from the destination
server. Use an internal mount. Call the NFS client nfs42_ssc_open to
obtain the NFS struct file suitable for nfsd_copy_range.
Ability to do "inter" server-to-server depends on the an nfsd kernel
parameter "inter_copy_offload_enable".
Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Introducing the COPY_NOTIFY operation.
Create a new unique stateid that will keep track of the copy
state and the upcoming READs that will use that stateid.
Each associated parent stateid has a list of copy
notify stateids. A copy notify structure makes a copy of
the parent stateid and a clientid and will use it to look
up the parent stateid during the READ request (suggested
by Trond Myklebust <trond.myklebust@hammerspace.com>).
At nfs4_put_stid() time, we walk the list of the associated
copy notify stateids and delete them.
Laundromat thread will traverse globally stored copy notify
stateid in idr and notice if any haven't been referenced in the
lease period, if so, it'll remove them.
Return single netaddr to advertise to the copy.
Suggested-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Signed-off-by: Andy Adamson <andros@netapp.com>
When we're destroying the client lease, and we call
nfsd4_shutdown_callback(), we must ensure that we do not return
before all outstanding callbacks have terminated and have
released their payloads.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Version 2 upcalls will allow the nfsd to include a hash of the kerberos
principal string in the Cld_Create upcall. If a principal is present in
the svc_cred, then the hash will be included in the Cld_Create upcall.
We attempt to use the svc_cred.cr_raw_principal (which is returned by
gssproxy) first, and then fall back to using the svc_cred.cr_principal
(which is returned by both gssproxy and rpc.svcgssd). Upon a subsequent
restart, the hash will be returned in the Cld_Gracestart downcall and
stored in the reclaim_str_hashtbl so it can be used when handling
reclaim opens.
Signed-off-by: Scott Mayhew <smayhew@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Have nfs4_preprocess_stateid_op pass back a nfsd_file instead of a filp.
Since we now presume that the struct file will be persistent in most
cases, we can stop fiddling with the raparms in the read code. This
also means that we don't really care about the rd_tmp_file field
anymore.
Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Have them keep an nfsd_file reference instead of a struct file.
Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Here is the "big" driver core and debugfs changes for 5.3-rc1
It's a lot of different patches, all across the tree due to some api
changes and lots of debugfs cleanups. Because of this, there is going
to be some merge issues with your tree at the moment, I'll follow up
with the expected resolutions to make it easier for you.
Other than the debugfs cleanups, in this set of changes we have:
- bus iteration function cleanups (will cause build warnings
with s390 and coresight drivers in your tree)
- scripts/get_abi.pl tool to display and parse Documentation/ABI
entries in a simple way
- cleanups to Documenatation/ABI/ entries to make them parse
easier due to typos and other minor things
- default_attrs use for some ktype users
- driver model documentation file conversions to .rst
- compressed firmware file loading
- deferred probe fixes
All of these have been in linux-next for a while, with a bunch of merge
issues that Stephen has been patient with me for. Other than the merge
issues, functionality is working properly in linux-next :)
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-----BEGIN PGP SIGNATURE-----
iG0EABECAC0WIQT0tgzFv3jCIUoxPcsxR9QN2y37KQUCXSgpnQ8cZ3JlZ0Brcm9h
aC5jb20ACgkQMUfUDdst+ykcwgCfS30OR4JmwZydWGJ7zK/cHqk+KjsAnjOxjC1K
LpRyb3zX29oChFaZkc5a
=XrEZ
-----END PGP SIGNATURE-----
Merge tag 'driver-core-5.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core
Pull driver core and debugfs updates from Greg KH:
"Here is the "big" driver core and debugfs changes for 5.3-rc1
It's a lot of different patches, all across the tree due to some api
changes and lots of debugfs cleanups.
Other than the debugfs cleanups, in this set of changes we have:
- bus iteration function cleanups
- scripts/get_abi.pl tool to display and parse Documentation/ABI
entries in a simple way
- cleanups to Documenatation/ABI/ entries to make them parse easier
due to typos and other minor things
- default_attrs use for some ktype users
- driver model documentation file conversions to .rst
- compressed firmware file loading
- deferred probe fixes
All of these have been in linux-next for a while, with a bunch of
merge issues that Stephen has been patient with me for"
* tag 'driver-core-5.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (102 commits)
debugfs: make error message a bit more verbose
orangefs: fix build warning from debugfs cleanup patch
ubifs: fix build warning after debugfs cleanup patch
driver: core: Allow subsystems to continue deferring probe
drivers: base: cacheinfo: Ensure cpu hotplug work is done before Intel RDT
arch_topology: Remove error messages on out-of-memory conditions
lib: notifier-error-inject: no need to check return value of debugfs_create functions
swiotlb: no need to check return value of debugfs_create functions
ceph: no need to check return value of debugfs_create functions
sunrpc: no need to check return value of debugfs_create functions
ubifs: no need to check return value of debugfs_create functions
orangefs: no need to check return value of debugfs_create functions
nfsd: no need to check return value of debugfs_create functions
lib: 842: no need to check return value of debugfs_create functions
debugfs: provide pr_fmt() macro
debugfs: log errors when something goes wrong
drivers: s390/cio: Fix compilation warning about const qualifiers
drivers: Add generic helper to match by of_node
driver_find_device: Unify the match function with class_find_device()
bus_find_device: Unify the match callback with class_find_device
...
Decode the implementation ID and display in nfsd/clients/#/info. It may
be help identify the client. It won't be used otherwise.
(When this went into the protocol, I thought the implementation ID would
be a slippery slope towards implementation-specific workarounds as with
the http user-agent. But I guess I was wrong, the risk seems pretty low
now.)
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Keep a second reference count which is what is really used to decide
when to free the client's memory.
Next I'm going to add an nfsd/clients/ directory with a subdirectory for
each NFSv4 client. File objects under nfsd/clients/ will hold these
references.
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Rename this to a more descriptive name: it counts the number of
in-progress rpc's referencing this client.
Next I'm going to add a second refcount with a slightly different use.
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
When calling debugfs functions, there is no need to ever check the
return value. The function can work or not, but the code logic should
never do something different based on this.
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: linux-nfs@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20190612152603.GB18440@kroah.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This will allow the reclaim_str_hashtbl to store either the recovery
directory names used by the legacy client tracking code or the full
client strings used by the nfsdcld client tracking code.
Signed-off-by: Scott Mayhew <smayhew@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
If there are multiple callbacks queued, waiting for the callback
slot when the callback gets shut down, then they all currently
end up acting as if they hold the slot, and call
nfsd4_cb_sequence_done() resulting in interesting side-effects.
In addition, the 'retry_nowait' path in nfsd4_cb_sequence_done()
causes a loop back to nfsd4_cb_prepare() without first freeing the
slot, which causes a deadlock when nfsd41_cb_get_slot() gets called
a second time.
This patch therefore adds a boolean to track whether or not the
callback did pick up the slot, so that it can do the right thing
in these 2 cases.
Cc: stable@vger.kernel.org
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
SUNRPC has two sorts of credentials, both of which appear as
"struct rpc_cred".
There are "generic credentials" which are supplied by clients
such as NFS and passed in 'struct rpc_message' to indicate
which user should be used to authorize the request, and there
are low-level credentials such as AUTH_NULL, AUTH_UNIX, AUTH_GSS
which describe the credential to be sent over the wires.
This patch replaces all the generic credentials by 'struct cred'
pointers - the credential structure used throughout Linux.
For machine credentials, there is a special 'struct cred *' pointer
which is statically allocated and recognized where needed as
having a special meaning. A look-up of a low-level cred will
map this to a machine credential.
Signed-off-by: NeilBrown <neilb@suse.com>
Acked-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Upon receiving a request for async copy, create a new kthread. If we
get asynchronous request, make sure to copy the needed arguments/state
from the stack before starting the copy. Then start the thread and reply
back to the client indicating copy is asynchronous.
nfsd_copy_file_range() will copy in a loop over the total number of
bytes is needed to copy. In case a failure happens in the middle, we
ignore the error and return how much we copied so far. Once done
creating a workitem for the callback workqueue and send CB_OFFLOAD with
the results.
The lifetime of the copy stateid is bound to the vfs copy. This way we
don't need to keep the nfsd_net structure for the callback. We could
keep it around longer so that an OFFLOAD_STATUS that came late would
still get results, but clients should be able to deal without that.
We handle OFFLOAD_CANCEL by sending a signal to the copy thread and
calling kthread_stop.
A client should cancel any ongoing copies before calling DESTROY_CLIENT;
if not, we return a CLIENT_BUSY error.
If the client is destroyed for some other reason (lease expiration, or
server shutdown), we must clean up any ongoing copies ourselves.
Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
[colin.king@canonical.com: fix leak in error case]
[bfields@fieldses.org: remove signalling, merge patches]
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Clean up: The global callback_cred is no longer used, so it can be
removed.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
atomic_t variables are currently used to implement reference
counters with the following properties:
- counter is initialized to 1 using atomic_set()
- a resource is freed upon counter reaching zero
- once counter reaches zero, its further
increments aren't allowed
- counter schema uses basic atomic operations
(set, inc, inc_not_zero, dec_and_test, etc.)
Such atomic variables should be converted to a newly provided
refcount_t type and API that prevents accidental counter overflows
and underflows. This is important since overflows and underflows
can lead to use-after-free situation and be exploitable.
The variable nfs4_file.fi_ref is used as pure reference counter.
Convert it to refcount_t and fix up the operations.
Suggested-by: Kees Cook <keescook@chromium.org>
Reviewed-by: David Windsor <dwindsor@gmail.com>
Reviewed-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
atomic_t variables are currently used to implement reference
counters with the following properties:
- counter is initialized to 1 using atomic_set()
- a resource is freed upon counter reaching zero
- once counter reaches zero, its further
increments aren't allowed
- counter schema uses basic atomic operations
(set, inc, inc_not_zero, dec_and_test, etc.)
Such atomic variables should be converted to a newly provided
refcount_t type and API that prevents accidental counter overflows
and underflows. This is important since overflows and underflows
can lead to use-after-free situation and be exploitable.
The variable nfs4_cntl_odstate.co_odcount is used as pure reference counter.
Convert it to refcount_t and fix up the operations.
Suggested-by: Kees Cook <keescook@chromium.org>
Reviewed-by: David Windsor <dwindsor@gmail.com>
Reviewed-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
atomic_t variables are currently used to implement reference
counters with the following properties:
- counter is initialized to 1 using atomic_set()
- a resource is freed upon counter reaching zero
- once counter reaches zero, its further
increments aren't allowed
- counter schema uses basic atomic operations
(set, inc, inc_not_zero, dec_and_test, etc.)
Such atomic variables should be converted to a newly provided
refcount_t type and API that prevents accidental counter overflows
and underflows. This is important since overflows and underflows
can lead to use-after-free situation and be exploitable.
The variable nfs4_stid.sc_count is used as pure reference counter.
Convert it to refcount_t and fix up the operations.
Suggested-by: Kees Cook <keescook@chromium.org>
Reviewed-by: David Windsor <dwindsor@gmail.com>
Reviewed-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
The spec allows us to return NFS4ERR_SEQ_FALSE_RETRY if we notice that
the client is making a call that matches a previous (slot, seqid) pair
but that *isn't* actually a replay, because some detail of the call
doesn't actually match the previous one.
Catching every such case is difficult, but we may as well catch a few
easy ones. This also handles the case described in the previous patch,
in a different way.
The spec does however require us to catch the case where the difference
is in the rpc credentials. This prevents somebody from snooping another
user's replies by fabricating retries.
(But the practical value of the attack is limited by the fact that the
replies with the most sensitive data are READ replies, which are not
normally cached.)
Tested-by: Olga Kornievskaia <aglo@umich.edu>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Currently our handling of 4.1+ requests without "cachethis" set is
confusing and not quite correct.
Suppose a client sends a compound consisting of only a single SEQUENCE
op, and it matches the seqid in a session slot (so it's a retry), but
the previous request with that seqid did not have "cachethis" set.
The obvious thing to do might be to return NFS4ERR_RETRY_UNCACHED_REP,
but the protocol only allows that to be returned on the op following the
SEQUENCE, and there is no such op in this case.
The protocol permits us to cache replies even if the client didn't ask
us to. And it's easy to do so in the case of solo SEQUENCE compounds.
So, when we get a solo SEQUENCE, we can either return the previously
cached reply or NFSERR_SEQ_FALSE_RETRY if we notice it differs in some
way from the original call.
Currently, we're returning a corrupt reply in the case a solo SEQUENCE
matches a previous compound with more ops. This actually matters
because the Linux client recently started doing this as a way to recover
from lost replies to idempotent operations in the case the process doing
the original reply was killed: in that case it's difficult to keep the
original arguments around to do a real retry, and the client no longer
cares what the result is anyway, but it would like to make sure that the
slot's sequence id has been incremented, and the solo SEQUENCE assures
that: if the server never got the original reply, it will increment the
sequence id. If it did get the original reply, it won't increment, and
nothing else that about the reply really matters much. But we can at
least attempt to return valid xdr!
Tested-by: Olga Kornievskaia <aglo@umich.edu>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
The rpccred gotten from rpc_lookup_machine_cred() should be put when
state is shutdown.
Signed-off-by: Kinglong Mee <kinglongmee@gmail.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
nfsd assigns the nfs4_free_lock_stateid to .sc_free in init_lock_stateid().
If nfsd doesn't go through init_lock_stateid() and put stateid at end,
there is a NULL reference to .sc_free when calling nfs4_put_stid(ns).
This patch let the nfs4_stid.sc_free assignment to nfs4_alloc_stid().
Cc: stable@vger.kernel.org
Fixes: 356a95ece7 "nfsd: clean up races in lock stateid searching..."
Signed-off-by: Kinglong Mee <kinglongmee@gmail.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
It's possible for a client to call in on a lock that is blocked for a
long time, but discontinue polling for it. A malicious client could
even set a lock on a file, and then spam the server with failing lock
requests from different lockowners that pile up in a DoS attack.
Add the blocked lock structures to a per-net namespace LRU when hashing
them, and timestamp them. If the lock request is not revisited after a
lease period, we'll drop it under the assumption that the client is no
longer interested.
This also gives us a mechanism to clean up these objects at server
shutdown time as well.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Create a new per-lockowner+per-inode structure that contains a
file_lock. Have nfsd4_lock add this structure to the lockowner's list
prior to setting the lock. Then call the vfs and request a blocking lock
(by setting FL_SLEEP). If we get anything besides FILE_LOCK_DEFERRED
back, then we dequeue the block structure and free it. When the next
lock request comes in, we'll look for an existing block for the same
filehandle and dequeue and reuse it if there is one.
When the lock comes free (a'la an lm_notify call), we dequeue it
from the lockowner's list and kick off a CB_NOTIFY_LOCK callback to
inform the client that it should retry the lock request.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
