Fix a soft lockup when NFS client delegation recovery is attempted
but the inode is in the process of being freed. When the
igrab(inode) call fails, and we have to restart the recovery process,
we need to ensure that we won't attempt to recover the same delegation
again.
Fixes: 45870d6909 ("NFSv4.1: Test delegation stateids when server...")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.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>
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>
Stable bugfixes:
- Revalidate "." and ".." correctly on open
- Avoid RCU usage in tracepoints
- Fix ugly referral attributes
- Fix a typo in nomigration mount option
- Revert "NFS: Move the flock open mode check into nfs_flock()"
Features:
- Implement a stronger send queue accounting system for NFS over RDMA
- Switch some atomics to the new refcount_t type
Other bugfixes and cleanups:
- Clean up access mode bits
- Remove special-case revalidations in nfs_opendir()
- Improve invalidating NFS over RDMA memory for async operations that time out
- Handle NFS over RDMA replies with a worqueue
- Handle NFS over RDMA sends with a workqueue
- Fix up replaying interrupted requests
- Remove dead NFS over RDMA definitions
- Update NFS over RDMA copyright information
- Be more consistent with bool initialization and comparisons
- Mark expected switch fall throughs
- Various sunrpc tracepoint cleanups
- Fix various OPEN races
- Fix a typo in nfs_rename()
- Use common error handling code in nfs_lock_and_join_request()
- Check that some structures are properly cleaned up during net_exit()
- Remove net pointer from dprintk()s
-----BEGIN PGP SIGNATURE-----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=2Zc1
-----END PGP SIGNATURE-----
Merge tag 'nfs-for-4.15-1' of git://git.linux-nfs.org/projects/anna/linux-nfs
Pull NFS client updates from Anna Schumaker:
"Stable bugfixes:
- Revalidate "." and ".." correctly on open
- Avoid RCU usage in tracepoints
- Fix ugly referral attributes
- Fix a typo in nomigration mount option
- Revert "NFS: Move the flock open mode check into nfs_flock()"
Features:
- Implement a stronger send queue accounting system for NFS over RDMA
- Switch some atomics to the new refcount_t type
Other bugfixes and cleanups:
- Clean up access mode bits
- Remove special-case revalidations in nfs_opendir()
- Improve invalidating NFS over RDMA memory for async operations that
time out
- Handle NFS over RDMA replies with a worqueue
- Handle NFS over RDMA sends with a workqueue
- Fix up replaying interrupted requests
- Remove dead NFS over RDMA definitions
- Update NFS over RDMA copyright information
- Be more consistent with bool initialization and comparisons
- Mark expected switch fall throughs
- Various sunrpc tracepoint cleanups
- Fix various OPEN races
- Fix a typo in nfs_rename()
- Use common error handling code in nfs_lock_and_join_request()
- Check that some structures are properly cleaned up during
net_exit()
- Remove net pointer from dprintk()s"
* tag 'nfs-for-4.15-1' of git://git.linux-nfs.org/projects/anna/linux-nfs: (62 commits)
NFS: Revert "NFS: Move the flock open mode check into nfs_flock()"
NFS: Fix typo in nomigration mount option
nfs: Fix ugly referral attributes
NFS: super: mark expected switch fall-throughs
sunrpc: remove net pointer from messages
nfs: remove net pointer from messages
sunrpc: exit_net cleanup check added
nfs client: exit_net cleanup check added
nfs/write: Use common error handling code in nfs_lock_and_join_requests()
NFSv4: Replace closed stateids with the "invalid special stateid"
NFSv4: nfs_set_open_stateid must not trigger state recovery for closed state
NFSv4: Check the open stateid when searching for expired state
NFSv4: Clean up nfs4_delegreturn_done
NFSv4: cleanup nfs4_close_done
NFSv4: Retry NFS4ERR_OLD_STATEID errors in layoutreturn
pNFS: Retry NFS4ERR_OLD_STATEID errors in layoutreturn-on-close
NFSv4: Don't try to CLOSE if the stateid 'other' field has changed
NFSv4: Retry CLOSE and DELEGRETURN on NFS4ERR_OLD_STATEID.
NFS: Fix a typo in nfs_rename()
NFSv4: Fix open create exclusive when the server reboots
...
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>
Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.
By default all files without license information are under the default
license of the kernel, which is GPL version 2.
Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.
This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.
How this work was done:
Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,
Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.
The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.
The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.
Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if <5
lines).
All documentation files were explicitly excluded.
The following heuristics were used to determine which SPDX license
identifiers to apply.
- when both scanners couldn't find any license traces, file was
considered to have no license information in it, and the top level
COPYING file license applied.
For non */uapi/* files that summary was:
SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 11139
and resulted in the first patch in this series.
If that file was a */uapi/* path one, it was "GPL-2.0 WITH
Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was:
SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 WITH Linux-syscall-note 930
and resulted in the second patch in this series.
- if a file had some form of licensing information in it, and was one
of the */uapi/* ones, it was denoted with the Linux-syscall-note if
any GPL family license was found in the file or had no licensing in
it (per prior point). Results summary:
SPDX license identifier # files
---------------------------------------------------|------
GPL-2.0 WITH Linux-syscall-note 270
GPL-2.0+ WITH Linux-syscall-note 169
((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21
((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17
LGPL-2.1+ WITH Linux-syscall-note 15
GPL-1.0+ WITH Linux-syscall-note 14
((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5
LGPL-2.0+ WITH Linux-syscall-note 4
LGPL-2.1 WITH Linux-syscall-note 3
((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3
((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1
and that resulted in the third patch in this series.
- when the two scanners agreed on the detected license(s), that became
the concluded license(s).
- when there was disagreement between the two scanners (one detected a
license but the other didn't, or they both detected different
licenses) a manual inspection of the file occurred.
- In most cases a manual inspection of the information in the file
resulted in a clear resolution of the license that should apply (and
which scanner probably needed to revisit its heuristics).
- When it was not immediately clear, the license identifier was
confirmed with lawyers working with the Linux Foundation.
- If there was any question as to the appropriate license identifier,
the file was flagged for further research and to be revisited later
in time.
In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.
Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights. The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.
Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.
In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.
Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
- a full scancode scan run, collecting the matched texts, detected
license ids and scores
- reviewing anything where there was a license detected (about 500+
files) to ensure that the applied SPDX license was correct
- reviewing anything where there was no detection but the patch license
was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
SPDX license was correct
This produced a worksheet with 20 files needing minor correction. This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.
These .csv files were then reviewed by Greg. Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected. This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.) Finally Greg ran the script using the .csv files to
generate the patches.
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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>
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>
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>
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>
Currently, if the application that holds the file open isn't doing
I/O, we may end up returning the delegation. This means that we can
no longer cache the file as aggressively, and often also that we
multiply the state that both the server and the client needs to track.
This patch adds a check for open files to the routine that scans
for delegations that are unreferenced.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
If the server reboots while we are converting a delegation into
OPEN/LOCK stateids as part of a delegation return, the current code
will simply exit with an error. This causes us to lose both
delegation state and locking state (i.e. locking atomicity).
Deal with this by exposing the delegation stateid during delegation
return, so that we can recover the delegation, and then resume
open/lock recovery.
Note that not having to hold the nfs_inode->rwsem across the
calls to nfs_delegation_claim_opens() also fixes a deadlock against
the NFSv4.1 reboot recovery code.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
This patch exports symbols needed by the v4 module. In addition, I also
switch over to using IS_ENABLED() to check if CONFIG_NFS_V4 or
CONFIG_NFS_V4_MODULE are set.
The module (nfs4.ko) will be created in the same directory as nfs.ko and
will be automatically loaded the first time you try to mount over NFS v4.
Signed-off-by: Bryan Schumaker <bjschuma@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Delegations are a v4 feature, so push return_delegation out of the
generic client by creating a new rpc_op and renaming the old function to
be in the nfs v4 "namespace"
Signed-off-by: Bryan Schumaker <bjschuma@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Delegations are a v4 feature, so push them out of the generic code.
Signed-off-by: Bryan Schumaker <bjschuma@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
I can use this function to return delegations and unset the pnfs layout
driver rather than continuing to do these things in the generic client.
With this change, we no longer need an nfs4_kill_super().
Signed-off-by: Bryan Schumaker <bjschuma@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
The assumption is that if you are in a situation where you need to
return the delegation, then you should probably stop caching the
data anyway.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
When the NFSv4.0 server tells us that it can no-longer talk to us
on the callback channel, we should attempt a new SETCLIENTID in
order to re-transmit the callback channel information.
Note that as long as we do not change the boot verifier, this is
a safe procedure; the server is required to keep our state.
Also move the function nfs_handle_cb_pathdown to fs/nfs/nfs4state.c,
and change the name in order to mark it as being specific to NFSv4.0.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
If we know that the delegation stateid is bad or revoked, we need to
remove that delegation as soon as possible, and then mark all the
stateids that relied on that delegation for recovery. We cannot use
the delegation as part of the recovery process.
Also note that NFSv4.1 uses a different error code (NFS4ERR_DELEG_REVOKED)
to indicate that the delegation was revoked.
Finally, ensure that setlk() and setattr() can both recover safely from
a revoked delegation.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org
Delegations are per-inode, not per-nfs_client. When a server file
system is migrated, delegations on the client must be moved from the
source to the destination nfs_server. Make it easier to manage a
mount point's delegation list across a migration event by moving the
list to the nfs_server struct.
Clean up: I added documenting comments to public functions I changed
in this patch. For consistency I added comments to all the other
public functions in fs/nfs/delegation.c.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
If the NFS_INO_REVAL_FORCED flag is set, that means that we don't yet have
an up to date attribute cache. Even if we hold a delegation, we must
put a GETATTR on the wire.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@kernel.org
in NFSv4.1 the seqid part of a stateid in CB_RECALL must be 0
Signed-off-by: Alexandros Batsakis <batsakis@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
For now the clients returns _all_ the delegations of the specificed type
it holds
Signed-off-by: Alexandros Batsakis <batsakis@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
The nfsv4 state manager could potentially deadlock inside
__nfs_inode_return_delegation() if the server reboots, so that the calls to
nfs_msync_inode() end up waiting on state recovery to complete.
Also ensure that if a server reboot or network partition causes us to have
to stop returning delegations, that NFS4CLNT_DELEGRETURN is set so that
the state manager can resume any outstanding delegation returns after it
has dealt with the state recovery situation.
Finally, ensure that the state manager doesn't wait for the DELEGRETURN
call to complete. It doesn't need to, and that too can cause a deadlock.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
If the client is not using a delegation, the right thing to do is to return
it as soon as possible. This helps reduce the amount of state the server
has to track, as well as reducing the potential for conflicts with other
clients.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Add a delegation cleanup phase to the state management loop, and do the
NFS4ERR_CB_PATH_DOWN recovery there.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Add a flag to mark delegations as requiring return, then run a garbage
collector. In the future, this will allow for more flexible delegation
management, where delegations may be marked for return if it turns out
that they are not being referenced.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
When we can update_open_stateid(), we need to be certain that we don't
race with a delegation return. While we could do this by grabbing the
nfs_client->cl_lock, a dedicated spin lock in the delegation structure
will scale better.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Otherwise, there is a potential deadlock if the last dput() from an NFSv4
close() or other asynchronous operation leads to nfs_clear_inode calling
the synchronous delegreturn.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
There appear to be some rogue servers out there that issue multiple
delegations with different stateids for the same file. Ensure that when we
return delegations, we do so on a per-stateid basis rather than a per-file
basis.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Rename struct nfs4_client to struct nfs_client so that it can become the basis
for a general client record for NFS2 and NFS3 in addition to NFS4.
Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
According to RFC3530 we're supposed to cache the change attribute
at the time the client receives a write delegation.
If the inode is clean, a CB_GETATTR callback by the server to the
client is supposed to return the cached change attribute.
If, OTOH, the inode is dirty, the client should bump the cached
change attribute by 1.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Delegations allow us to cache posix and BSD locks, however when the
delegation is recalled, we need to "flush the cache" and send
the cached LOCK requests to the server.
This patch sets up the mechanism for doing so.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
