If the attempt to recall the delegation fails because the inode is
in the process of being evicted from cache, then use NFS4ERR_DELAY
to ask the server to retry later.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
If there are attributes that are still invalid when we set a delegation,
then we need to set the NFS_INO_REVAL_FORCED flag.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
There are three places that walk all delegation for an nfs_client and
restart whenever they find something interesting - potentially
resulting in a quadratic search: If there are 10,000 uninteresting
delegations followed by 10,000 interesting one, then the code
skips over 100,000,000 delegations, which can take a noticeable amount
of time.
Of these nfs_delegation_reap_unclaimed() and
nfs_reap_expired_delegations() are only called during unusual events:
a server reboots or reports expired delegations, probably due to a
network partition. Optimizing these is not particularly important.
The third, nfs_client_return_marked_delegations(), is called
periodically via nfs_expire_unreferenced_delegations(). It could
cause periodic problems on a busy server.
New delegations are added to the end of the list, so if there are
10,000 open files with delegations, and 10,000 more recently opened files
that received delegations but are now closed, then
nfs_client_return_marked_delegations() can take seconds to skip over
the 10,000 open files 10,000 times. That is a waste of time.
The avoid this waste a place-holder (an inode) is kept when locks are
dropped, so that the place can usually be found again after taking
rcu_readlock(). This place holder ensure that we find the right
starting point in the list of nfs_servers, and makes is probable that
we find the right starting point in the list of delegations.
We might need to occasionally restart at the head of that list.
It might be possible that the place_holder inode could lose its
delegation separately, and then get a new one using the same (freed
and then reallocated) 'struct nfs_delegation'. Were this to happen,
the new delegation would be at the end of the list and we would miss
returning some other delegations. This would have the effect of
unnecessarily delaying the return of some unused delegations until the
next time this function is called - typically 90 seconds later. As
this is not a correctness issue and is vanishingly unlikely to happen,
it does not seem worth addressing.
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
In three places we walk the list of delegations for an nfs_client
until an interesting one is found, then we act of that delegation
and restart the walk.
New delegations are added to the end of a list and the interesting
delegations are usually old, so in many case we won't repeat
a long walk over and over again, but it is possible - particularly if
the first server in the list has a large number of uninteresting
delegations.
In each cache the work done on interesting delegations will often
complete without sleeping, so this could loop many times without
giving up the CPU.
So add a cond_resched() at an appropriate point to avoid hogging the
CPU for too long.
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
There are 3 places where we walk the list of delegations
for an nfs_client.
In each case there are two nested loops, one for nfs_servers
and one for nfs_delegations.
When we find an interesting delegation we try to get an active
reference to the server. If that fails, it is pointless to
continue to look at the other delegation for the server as
we will never be able to get an active reference.
So instead of continuing in the inner loop, break out
and continue in the outer loop.
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Neither nfs_inode_set_delegation() nor nfs_inode_reclaim_delegation() are
generic code. They have no business delving into NFSv4 OPEN xdr structures,
so let's replace the "struct nfs_openres" parameter.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Starting with NFSv4.1, the server is able to deduce the client id from
the SEQUENCE op which means it can always figure out whether or not
the client is holding a delegation on a file that is being changed.
For that reason, RFC5661 does not require a delegation to be unconditionally
recalled on operations such as SETATTR, RENAME, or REMOVE.
Note that for now, we continue to return READ delegations since that is
still expected by the Linux knfsd server.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
For NFS, we just use the "raw" API since the i_version is mostly
managed by the server. The exception there is when the client
holds a write delegation, but we only need to bump it once
there anyway to handle CB_GETATTR.
Tested-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
If we're racing with an OPEN, then retry the operation instead of
declaring it a success.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
[Andrew W Elble: Fix a typo in nfs4_refresh_open_stateid]
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
The NFS_INO_REVAL_FORCED flag needs to be set if we just got a delegation,
and we see that there might still be some ambiguity as to whether or not
our attribute or data cache are valid.
In practice, this means that a call to nfs_check_inode_attributes() will
have noticed a discrepancy between cached attributes and measured ones,
so let's move the setting of NFS_INO_REVAL_FORCED to there.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Don't rely on nfs_inode_detach_delegation() succeeding. That can race...
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Tested-by: Oleg Drokin <green@linuxhacker.ru>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
If we race with a delegreturn before taking the spin lock, we
currently end up dropping the delegation stateid.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Tested-by: Oleg Drokin <green@linuxhacker.ru>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Modify the helper nfs_inode_find_state_and_recover() so that it
can check all open/lock/delegation state trackers on that inode for
whether or not they need are affected by a revoked stateid error.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Tested-by: Oleg Drokin <green@linuxhacker.ru>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
This fixes a potential infinite loop in nfs_reap_expired_delegations.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Tested-by: Oleg Drokin <green@linuxhacker.ru>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Ensure that if the server reboots while we're testing and recovering
from revoked delegations, we exit to allow the state manager to
handle matters.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Tested-by: Oleg Drokin <green@linuxhacker.ru>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
According to RFC5661, if any of the SEQUENCE status bits
SEQ4_STATUS_EXPIRED_ALL_STATE_REVOKED,
SEQ4_STATUS_EXPIRED_SOME_STATE_REVOKED, SEQ4_STATUS_ADMIN_STATE_REVOKED,
or SEQ4_STATUS_RECALLABLE_STATE_REVOKED are set, then we need to use
TEST_STATEID to figure out which stateids have been revoked, so we
can acknowledge the loss of state using FREE_STATEID.
While we already do this for open and lock state, we have not been doing
so for all the delegations.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Tested-by: Oleg Drokin <green@linuxhacker.ru>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Allow the callers of nfs_remove_bad_delegation() to specify the stateid
that needs to be marked as bad.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Tested-by: Oleg Drokin <green@linuxhacker.ru>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
We must not allow the use of delegations that have been revoked or are
being returned.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Fixes: 869f9dfa4d ("NFSv4: Fix races between nfs_remove_bad_delegation()...")
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Cc: stable@vger.kernel.org # v3.19+
Tested-by: Oleg Drokin <green@linuxhacker.ru>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
If the delegation is revoked, then it can't be used for caching.
Fixes: 869f9dfa4d ("NFSv4: Fix races between nfs_remove_bad_delegation()...")
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Cc: stable@vger.kernel.org # v3.19+
Tested-by: Oleg Drokin <green@linuxhacker.ru>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
When we're using a delegation to represent our open state, we should
ensure that we use the stateid that was used to create that delegation.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
When a read delegation is being recalled, and we're reclaiming the
cached opens, we need to make sure that we only reclaim read-only
modes.
A previous attempt to do this, relied on retrieving the delegation
type from the nfs4_opendata structure. Unfortunately, as Kinglong
pointed out, this field can only be set when performing reboot recovery.
Furthermore, if we call nfs4_open_recover(), then we end up clobbering
the state->flags for all modes that we're not recovering...
The fix is to have the delegation recall code pass this information
to the recovery call, and then refactor the recovery code so that
nfs4_open_delegation_recall() does not need to call nfs4_open_recover().
Reported-by: Kinglong Mee <kinglongmee@gmail.com>
Fixes: 39f897fdbd ("NFSv4: When returning a delegation, don't...")
Tested-by: Kinglong Mee <kinglongmee@gmail.com>
Cc: NeilBrown <neilb@suse.com>
Cc: stable@vger.kernel.org # v4.2+
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
The NFSv4 delegation spec allows the server to tell a client to limit how
much data it cache after the file is closed. In return, the server
guarantees enough free space to avoid ENOSPC situations, etc.
Prior to this patch, we assumed we could always cache aggressively after
close. Unfortunately, this causes problems with servers that set the
limit to 0 and therefore do not offer any ENOSPC guarantees.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Since we're tracking modifications to the page cache on a per-page
basis, it makes sense to express the limit to how much we may cache
in units of pages.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
* bugfixes:
NFSv4: Return delegations synchronously in evict_inode
SUNRPC: Fix a regression when reconnecting
NFS: remount with security change should return EINVAL
nfs: do not export discarded symbols
NFSv4.1: don't export static symbol
Kinglong Mee reports that asynchronous delegations are being killed
by the call to rpc_shutdown_client() when unmounting. This can lead
to state leakage on the server until the client lease expires.
Reported-by: Kinglong Mee <kinglongmee@gmail.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Do so on the assumption that for most use cases, that list will turn into
a more or less LRU-ordered list, and so the list traversals in
nfs_client_return_marked_delegations() are likely to be shorter before
hitting a candidate to return.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
In nfs_client_return_marked_delegations() and nfs_delegation_reap_unclaimed()
we want to optimise the loop traversal by skipping delegations that are
already in the process of being returned.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
This patch ensures that the superblock doesn't go ahead and disappear
underneath us while the state manager thread is returning delegations.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Ensure that nfs_inode_set_delegation() doesn't inadvertently detach a
delegation that is already in the process of being returned.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Merge cleanups requested by Linus.
* cleanups: (3 commits)
pnfs: Refactor the *_layout_mark_request_commit to use pnfs_layout_mark_request_commit
nfs: Can call nfs_clear_page_commit() instead
nfs: Provide and use helper functions for marking a page as unstable
Highlights incluse:
Features:
- Removing the forced serialisation of open()/close() calls in NFSv4.x (x>0)
makes for a significant performance improvement in metadata intensive
workloads.
- Full support for the pNFS "flexible files" layout type
- Further RPC/RDMA client improvements from Chuck
Bugfixes:
- Stable fix: NFSv4.1 backchannel calls blocking operations with !TASK_RUNNING
- Stable fix: pnfs_generic_pg_init_read/write can be called with lseg == NULL
- Stable fix: Fix an Oopsable condition when nsm_mon_unmon is called as part
of the namespace cleanup,
- Stable fix: Ensure we reference the inode for return-on-close in delegreturn
- Use SO_REUSEPORT to ensure that NFSv3 TCP connections can rebind to the
same source address/port combination during a disconnect/reconnect event.
This is a requirement imposed by most NFSv3 server duplicate reply cache
implementations.
Optimisations:
- Ask for no NFSv4.1 delegations on OPEN if using O_DIRECT
Other:
- Add Anna Schumaker as co-maintainer for the NFS client
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Merge tag 'nfs-for-3.20-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs
Pull NFS client updates from Trond Myklebust:
"Highlights incluse:
Features:
- Removing the forced serialisation of open()/close() calls in
NFSv4.x (x>0) makes for a significant performance improvement in
metadata intensive workloads.
- Full support for the pNFS "flexible files" layout type
- Further RPC/RDMA client improvements from Chuck
Bugfixes:
- Stable fix: NFSv4.1 backchannel calls blocking operations with !TASK_RUNNING
- Stable fix: pnfs_generic_pg_init_read/write can be called with lseg == NULL
- Stable fix: Fix an Oopsable condition when nsm_mon_unmon is called
as part of the namespace cleanup,
- Stable fix: Ensure we reference the inode for return-on-close in
delegreturn
- Use SO_REUSEPORT to ensure that NFSv3 TCP connections can rebind to
the same source address/port combination during a disconnect/
reconnect event. This is a requirement imposed by most NFSv3
server duplicate reply cache implementations.
Optimisations:
- Ask for no NFSv4.1 delegations on OPEN if using O_DIRECT
Other:
- Add Anna Schumaker as co-maintainer for the NFS client"
* tag 'nfs-for-3.20-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs: (119 commits)
SUNRPC: Cleanup to remove xs_tcp_close()
pnfs: delete an unintended goto
pnfs/flexfiles: Do not dprintk after the free
SUNRPC: Fix stupid typo in xs_sock_set_reuseport
SUNRPC: Define xs_tcp_fin_timeout only if CONFIG_SUNRPC_DEBUG
SUNRPC: Handle connection reset more efficiently.
SUNRPC: Remove the redundant XPRT_CONNECTION_CLOSE flag
SUNRPC: Make xs_tcp_close() do a socket shutdown rather than a sock_release
SUNRPC: Ensure xs_tcp_shutdown() requests a full close of the connection
SUNRPC: Cleanup to remove remaining uses of XPRT_CONNECTION_ABORT
SUNRPC: Remove TCP socket linger code
SUNRPC: Remove TCP client connection reset hack
SUNRPC: TCP/UDP always close the old socket before reconnecting
SUNRPC: Add helpers to prevent socket create from racing
SUNRPC: Ensure xs_reset_transport() resets the close connection flags
SUNRPC: Do not clear the source port in xs_reset_transport
SUNRPC: Handle EADDRINUSE on connect
SUNRPC: Set SO_REUSEPORT socket option for TCP connections
NFSv4.1: Fix pnfs_put_lseg races
NFSv4.1: pnfs_send_layoutreturn should use GFP_NOFS
...
Ensure that we deal correctly with the case where the server sends us a
newer instance of the same delegation. If the stateids match, but the
sequence numbers differ, then treat the new delegation as if it were
an atomic upgrade.
Signed-off-by: Trond Myklebust <Trond.Myklebust@primarydata.com>
We can now add a dedicated spinlock without expanding struct inode.
Change to using that to protect the various i_flctx lists.
Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Acked-by: Christoph Hellwig <hch@lst.de>
Any attempt to call nfs_remove_bad_delegation() while a delegation is being
returned is currently a no-op. This means that we can end up looping
forever in nfs_end_delegation_return() if something causes the delegation
to be revoked.
This patch adds a mechanism whereby the state recovery code can communicate
to the delegation return code that the delegation is no longer valid and
that it should not be used when reclaiming state.
It also changes the return value for nfs4_handle_delegation_recall_error()
to ensure that nfs_end_delegation_return() does not reattempt the lock
reclaim before state recovery is done.
http://lkml.kernel.org/r/CAN-5tyHwG=Cn2Q9KsHWadewjpTTy_K26ee+UnSvHvG4192p-Xw@mail.gmail.com
Cc: stable@vger.kernel.org
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
The clean-up in commit 36281caa83 ended up removing a NULL pointer check
that is needed in order to prevent an Oops in
nfs_async_inode_return_delegation().
Reported-by: "Yan, Zheng" <zheng.z.yan@intel.com>
Link: http://lkml.kernel.org/r/5313E9F6.2020405@intel.com
Fixes: 36281caa83 (NFSv4: Further clean-ups of delegation stateid validation)
Cc: stable@vger.kernel.org # 3.4+
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Set up tracepoints to track when delegations are set, reclaimed,
returned by the client, or recalled by the server.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Having a global lock that protects all of this code is a clear
scalability problem. Instead of doing that, move most of the code to be
protected by the i_lock instead. The exceptions are the global lists
that the ->fl_link sits on, and the ->fl_block list.
->fl_link is what connects these structures to the
global lists, so we must ensure that we hold those locks when iterating
over or updating these lists.
Furthermore, sound deadlock detection requires that we hold the
blocked_list state steady while checking for loops. We also must ensure
that the search and update to the list are atomic.
For the checking and insertion side of the blocked_list, push the
acquisition of the global lock into __posix_lock_file and ensure that
checking and update of the blocked_list is done without dropping the
lock in between.
On the removal side, when waking up blocked lock waiters, take the
global lock before walking the blocked list and dequeue the waiters from
the global list prior to removal from the fl_block list.
With this, deadlock detection should be race free while we minimize
excessive file_lock_lock thrashing.
Finally, in order to avoid a lock inversion problem when handling
/proc/locks output we must ensure that manipulations of the fl_block
list are also protected by the file_lock_lock.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
The second check was added in commit 65b62a29 but it will never be true.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
If the state manager thread is already running, we may end up
racing with it in nfs_client_return_marked_delegations. Better to
just allow the state manager thread to do the job.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
