Commit Graph

411 Commits

Author SHA1 Message Date
Trond Myklebust
30cb3ee299 pNFS: Handle NFS4ERR_OLD_STATEID on layoutreturn by bumping the state seqid
If a LAYOUTRETURN receives a reply of NFS4ERR_OLD_STATEID then assume we've
missed an update, and just bump the stateid.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2019-09-20 15:48:35 -04:00
Trond Myklebust
6109bcf713 NFSv4: Handle RPC level errors in LAYOUTRETURN
Handle RPC level errors by assuming that the RPC call was successful.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2019-09-20 15:39:56 -04:00
Trond Myklebust
078a432d1c NFSv4: Handle NFS4ERR_DELAY correctly in return-on-close
If the server sends a NFS4ERR_DELAY, then allow the caller to retry.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2019-09-20 15:36:58 -04:00
Trond Myklebust
287a9c558b NFSv4: Clean up pNFS return-on-close error handling
Both close and delegreturn have identical code to handle pNFS
return-on-close. This patch refactors that code and places it
in pnfs.c

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2019-09-20 15:27:51 -04:00
Trond Myklebust
9c47b18cf7 pNFS: Ensure we do clear the return-on-close layout stateid on fatal errors
IF the server rejected our layout return with a state error such as
NFS4ERR_BAD_STATEID, or even a stale inode error, then we do want
to clear out all the remaining layout segments and mark that stateid
as invalid.

Fixes: 1c5bd76d17 ("pNFS: Enable layoutreturn operation for...")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2019-09-20 15:17:42 -04:00
Trond Myklebust
731c74dd98 NFSv4: Report the error from nfs4_select_rw_stateid()
In pnfs_update_layout() ensure that we do report any fatal errors from
nfs4_select_rw_stateid().

Fixes: d9aba2b40d ("NFSv4: Don't use the zero stateid with layoutget")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2019-08-04 22:35:40 -04:00
Trond Myklebust
d5b9216fd5 pnfs/flexfiles: Add tracepoints for detecting pnfs fallback to MDS
Add tracepoints to allow debugging of the event chain leading to
a pnfs fallback to doing I/O through the MDS.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2019-07-18 15:50:28 -04:00
Trond Myklebust
58bbeab425 pnfs: Fix a problem where we gratuitously start doing I/O through the MDS
If the client has to stop in pnfs_update_layout() to wait for another
layoutget to complete, it currently exits and defaults to I/O through
the MDS if the layoutget was successful.

Fixes: d03360aaf5 ("pNFS: Ensure we return the error if someone kills...")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: stable@vger.kernel.org # v4.20+
2019-07-18 15:33:42 -04:00
Trond Myklebust
d9aba2b40d NFSv4: Don't use the zero stateid with layoutget
The NFSv4.1 protocol explicitly forbids us from using the zero stateid
together with layoutget, so when we see that nfs4_select_rw_stateid()
is unable to return a valid delegation, lock or open stateid, then
we should initiate recovery and retry.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2019-07-18 14:43:52 -04:00
Trond Myklebust
2b17d725f9 NFS: Clean up writeback code
Now that the VM promises never to recurse back into the filesystem
layer on writeback, remove all the GFP_NOFS references etc from
the generic writeback code.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2019-07-06 14:54:52 -04:00
Trond Myklebust
9fcd5960e8 NFS: Add a helper to return a pointer to the open context of a struct nfs_page
Add a helper for when we remove the explicit pointer to the open
context.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2019-04-25 14:18:15 -04:00
Trond Myklebust
400417b05f pNFS: Fix a typo in pnfs_update_layout
We're supposed to wait for the outstanding layout count to go to zero,
but that got lost somehow.

Fixes: d03360aaf5 ("pNFS: Ensure we return the error if someone...")
Reported-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2019-03-12 16:04:51 -04:00
Trond Myklebust
5085607d20 NFS/pnfs: Bulk destroy of layouts needs to be safe w.r.t. umount
If a bulk layout recall or a metadata server reboot coincides with a
umount, then holding a reference to an inode is unsafe unless we
also hold a reference to the super block.

Fixes: fd9a8d7160 ("NFSv4.1: Fix bulk recall and destroy of layouts")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2019-02-23 13:59:29 -05:00
NeilBrown
a52458b48a NFS/NFSD/SUNRPC: replace generic creds with 'struct cred'.
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>
2018-12-19 13:52:46 -05:00
Trond Myklebust
0de43976fb NFS: Convert lookups of the open context to RCU
Reduce contention on the inode->i_lock by ensuring that we use RCU
when looking up the NFS open context.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2018-09-30 15:35:17 -04:00
Trond Myklebust
28ced9a84c pNFS: Don't allocate more pages than we need to fit a layoutget response
For the 'files' and 'flexfiles' layout types, we do not expect the reply
to be any larger than 4k. The block and scsi layout types are a little more
greedy, so we keep allocating the maximum response size for now.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2018-09-30 15:35:16 -04:00
Trond Myklebust
a2791d3a2c pNFS: Don't zero out the array in nfs4_alloc_pages()
We don't need a zeroed out array, since it is immediately being filled.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2018-09-30 15:35:16 -04:00
Trond Myklebust
d03360aaf5 pNFS: Ensure we return the error if someone kills a waiting layoutget
If someone interrupts a wait on one or more outstanding layoutgets in
pnfs_update_layout() then return the ERESTARTSYS/EINTR error.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2018-09-14 16:24:08 -04:00
Trond Myklebust
0af4c8be97 pNFS: Remove unwanted optimisation of layoutget
If we knew that the file was empty, we wouldn't be asking for a layout.
Any optimisation here is already done before calling pnfs_update_layout().
As it stands, we sometimes end up doing an unnecessary inband read to
the MDS even when holding a layout.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2018-08-21 13:39:08 -04:00
Trond Myklebust
ea51f94b45 pNFS: Treat RECALLCONFLICT like DELAY...
Yes, it is possible to get trapped in a loop, but the server should be
administratively revoking the recalled layout if it never gets returned.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2018-08-16 13:47:09 -04:00
Trond Myklebust
ecf8402603 pNFS: When updating the stateid in layoutreturn, also update the recall range
When we update the layout stateid in nfs4_layoutreturn_refresh_stateid, we
should also update the range in order to let the server know we're actually
returning everything.

Fixes: 16c278dbfa63 ("pnfs: Fix handling of NFS4ERR_OLD_STATEID replies...")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2018-08-16 13:29:36 -04:00
Gustavo A. R. Silva
10db5b7a2f pnfs: Use true and false for boolean values
Return statements in functions returning bool should use true or false
instead of an integer value.

This issue was detected with the help of Coccinelle.

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2018-08-08 16:50:03 -04:00
Trond Myklebust
2230ca0d28 pnfs: pnfs_find_lseg() should not check NFS_LSEG_LAYOUTRETURN
Layout segment validity is determined only by the NFS_LSEG_VALID flag. If
it is set, the layout segment is finable. As it is, when the flexfiles
driver sets NFS_LSEG_LAYOUTRETURN to indicate that we cannot discard
the layout segment, but that it must be returned, then this can result
in an unnecessary layoutget storm.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2018-08-08 16:50:03 -04:00
Trond Myklebust
c16467dc03 pnfs: Fix handling of NFS4ERR_OLD_STATEID replies to layoutreturn
If the server tells us that out layoutreturn raced with another layout
update, then we must ensure that the new layout segments are not in use
before we resend with an updated layout stateid.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2018-08-08 16:50:01 -04:00
Trond Myklebust
af9b6d7570 pNFS: Parse the results of layoutget on open even if permissions checks fail
Even if the results of the permissions checks failed, we should parse
the results of the layout on open call so that we can return the
layout if required.
Note that we also want to ignore the sequence counter for whether or not
a layout recall occurred. If the recall pertained to our OPEN, then the
callback will know, and will attempt to wait for us to finih processing
anyway.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2018-07-26 16:25:25 -04:00
Trond Myklebust
411ae722d1 pNFS: Wait for stale layoutget calls to complete in pnfs_update_layout()
If the old layout was recalled, and we returned NFS4ERR_NOMATCHINGLAYOUT
then we need to wait for all outstanding layoutget calls to complete
before we can send a new one.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2018-07-26 16:25:25 -04:00
Trond Myklebust
f0b429819b pNFS: Ignore non-recalled layouts in pnfs_layout_need_return()
If a layout has been recalled, then we should fire off a layoutreturn as
soon as all the layout segments that match the recall have been retired.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2018-07-26 16:25:25 -04:00
Trond Myklebust
e0b7d420f7 pNFS: Don't discard layout segments that are marked for return
If there are layout segments that are marked for return, then we need
to ensure that pnfs_mark_matching_lsegs_return() does not just
silently discard them, but it should tell the caller that there is a
layoutreturn scheduled.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2018-07-26 16:25:24 -04:00
Olga Kornievskaia
93b7f7ad20 skip LAYOUTRETURN if layout is invalid
Currently, when IO to DS fails, client returns the layout and
retries against the MDS. However, then on umounting (inode eviction)
it returns the layout again.

This is because pnfs_return_layout() was changed in
commit d78471d32b ("pnfs/blocklayout: set PNFS_LAYOUTRETURN_ON_ERROR")
to always set NFS_LAYOUT_RETURN_REQUESTED so even if we returned
the layout, it will be returned again. Instead, let's also check
if we have already marked the layout invalid.

Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2018-06-12 08:48:04 -04:00
Trond Myklebust
32f1c28f3d pnfs: Don't call commit on failed layoutget-on-open
If the layoutget on open call failed, we can't really commit the inode,
so don't bother calling it.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2018-05-31 15:03:12 -04:00
Trond Myklebust
64294b08f9 pNFS: Don't send LAYOUTGET on OPEN for read, if we already have cached data
If we're only opening the file for reading, and the file is empty and/or
we already have cached data, then heuristically optimise away the
LAYOUTGET.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2018-05-31 15:03:12 -04:00
Trond Myklebust
8dc96566c0 NFSv4/pnfs: Don't switch off layoutget-on-open for transient errors
Ensure that we only switch off the LAYOUTGET operation in the OPEN
compound when the server is truly broken, and/or it is complaining
that the compound is too large.
Currently, we end up turning off the functionality permanently,
even for transient errors such as EACCES or ENOSPC.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2018-05-31 15:03:11 -04:00
Trond Myklebust
d49e0d5b99 NFSv4/pnfs: Ensure pnfs_parse_lgopen() won't try to parse uninitialised data
We need to ensure that pnfs_parse_lgopen() doesn't try to parse a
struct nfs4_layoutget_res that was not filled by a successful call
to decode_layoutget(). This can happen if we performed a cached open,
or if either the OP_ACCESS or OP_GETATTR operations preceding the
OP_LAYOUTGET in the compound returned an error.

By initialising the 'status' field to NFS4ERR_DELAY, we ensure that
pnfs_parse_lgopen() won't try to interpret the structure.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2018-05-31 15:03:11 -04:00
Fred Isaman
30ae2412e9 pnfs: Fix manipulation of NFS_LAYOUT_FIRST_LAYOUTGET
The flag was not always being cleared after LAYOUTGET on OPEN.

Signed-off-by: Fred Isaman <fred.isaman@gmail.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2018-05-31 15:03:11 -04:00
Fred Isaman
c49b5209f9 pnfs: Add barrier to prevent lgopen using LAYOUTGET during recall
Since the LAYOUTGET on OPEN can be sent without prior inode information,
existing methods to prevent LAYOUTGET from being sent while processing
CB_LAYOUTRECALL don't work.  Track if a recall occurred while LAYOUTGET
was being sent, and if so ignore the results.

Signed-off-by: Fred Isaman <fred.isaman@gmail.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2018-05-31 15:03:11 -04:00
Fred Isaman
6e01260cee pnfs: Stop attempting LAYOUTGET on OPEN on failure
Signed-off-by: Fred Isaman <fred.isaman@gmail.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2018-05-31 15:03:11 -04:00
Fred Isaman
78746a384c pnfs: Add LAYOUTGET to OPEN of an existing file
Signed-off-by: Fred Isaman <fred.isaman@gmail.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2018-05-31 15:03:11 -04:00
Trond Myklebust
29a8bfe52d pNFS: Refactor nfs4_layoutget_release()
Move the actual freeing of the struct nfs4_layoutget into fs/nfs/pnfs.c
where it can be reused by the layoutget on open code.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2018-05-31 15:03:11 -04:00
Fred Isaman
2409a976a2 pnfs: Add LAYOUTGET to OPEN of a new file
This triggers when have no pre-existing inode to attach to.
The preexisting case is saved for later.

Signed-off-by: Fred Isaman <fred.isaman@gmail.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2018-05-31 15:03:11 -04:00
Fred Isaman
5e36e2a941 pnfs: Change pnfs_alloc_init_layoutget_args call signature
Don't send in a layout, instead use the (possibly NULL) inode.

This is needed for LAYOUTGET attached to an OPEN where the inode is not
yet set.

Signed-off-by: Fred Isaman <fred.isaman@gmail.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2018-05-31 15:03:11 -04:00
Fred Isaman
1b146fcff7 pnfs: Move nfs4_opendata into nfs4_fs.h
It will be needed now by the pnfs code.

Signed-off-by: Fred Isaman <fred.isaman@gmail.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2018-05-31 15:03:11 -04:00
Fred Isaman
dacb452db8 pnfs: move allocations out of nfs4_proc_layoutget
They work better in the new alloc_init function.

Signed-off-by: Fred Isaman <fred.isaman@gmail.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2018-05-31 15:03:11 -04:00
Fred Isaman
587f03deb6 pnfs: refactor send_layoutget
Pull out the alloc/init part for eventual reuse by OPEN.

Signed-off-by: Fred Isaman <fred.isaman@gmail.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2018-05-31 15:03:11 -04:00
Trond Myklebust
9c6376ebdd pNFS: Prevent the layout header refcount going to zero in pnfs_roc()
Ensure that we hold a reference to the layout header when processing
the pNFS return-on-close so that the refcount value does not inadvertently
go to zero.

Reported-by: Tigran Mkrtchyan <tigran.mkrtchyan@desy.de>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Cc: stable@vger.kernel.org # v4.10+
Tested-by: Tigran Mkrtchyan <tigran.mkrtchyan@desy.de>
2018-03-08 12:56:31 -05:00
Scott Mayhew
ba4a76f703 nfs/pnfs: fix nfs_direct_req ref leak when i/o falls back to the mds
Currently when falling back to doing I/O through the MDS (via
pnfs_{read|write}_through_mds), the client frees the nfs_pgio_header
without releasing the reference taken on the dreq
via pnfs_generic_pg_{read|write}pages -> nfs_pgheader_init ->
nfs_direct_pgio_init.  It then takes another reference on the dreq via
nfs_generic_pg_pgios -> nfs_pgheader_init -> nfs_direct_pgio_init and
as a result the requester will become stuck in inode_dio_wait.  Once
that happens, other processes accessing the inode will become stuck as
well.

Ensure that pnfs_read_through_mds() and pnfs_write_through_mds() clean
up correctly by calling hdr->completion_ops->completion() instead of
calling hdr->release() directly.

This can be reproduced (sometimes) by performing "storage failover
takeover" commands on NetApp filer while doing direct I/O from a client.

This can also be reproduced using SystemTap to simulate a failure while
doing direct I/O from a client (from Dave Wysochanski
<dwysocha@redhat.com>):

stap -v -g -e 'probe module("nfs_layout_nfsv41_files").function("nfs4_fl_prepare_ds").return { $return=NULL; exit(); }'

Suggested-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Scott Mayhew <smayhew@redhat.com>
Fixes: 1ca018d28d ("pNFS: Fix a memory leak when attempted pnfs fails")
Cc: stable@vger.kernel.org
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2018-01-14 23:06:29 -05:00
Benjamin Coddington
b3dce6a2f0 pnfs/blocklayout: handle transient devices
PNFS block/SCSI layouts should gracefully handle cases where block devices
are not available when a layout is retrieved, or the block devices are
removed while the client holds a layout.

While setting up a layout segment, keep a record of an unavailable or
un-parsable block device in cache with a flag so that subsequent layouts do
not spam the server with GETDEVINFO.  We can reuse the current
NFS_DEVICEID_UNAVAILABLE handling with one variation: instead of reusing
the device, we will discard it and send a fresh GETDEVINFO after the
timeout, since the lookup and validation of the device occurs within the
GETDEVINFO response handling.

A lookup of a layout segment that references an unavailable device will
return a segment with the NFS_LSEG_UNAVAILABLE flag set.  This will allow
the pgio layer to mark the layout with the appropriate fail bit, which
forces subsequent IO to the MDS, and prevents spamming the server with
LAYOUTGET, LAYOUTRETURN.

Finally, when IO to a block device fails, look up the block device(s)
referenced by the pgio header, and mark them as unavailable.

Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2018-01-14 23:06:29 -05:00
Trond Myklebust
7380020e77 pNFS: Retry NFS4ERR_OLD_STATEID errors in layoutreturn-on-close
If our layoutreturn on close operation returns an NFS4ERR_OLD_STATEID,
then try to update the stateid and retry. We know that there should
be no further LAYOUTGET requests being launched.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2017-11-17 16:43:47 -05:00
Thomas Meyer
6089dd0d73 NFS: Fix bool initialization/comparison
Bool initializations should use true and false. Bool tests don't need
comparisons.

Signed-off-by: Thomas Meyer <thomas@m3y3r.de>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2017-11-17 16:43:43 -05:00
Elena Reshetova
2b28a7bee4 fs, nfs: convert pnfs_layout_hdr.plh_refcount from atomic_t to refcount_t
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 pnfs_layout_hdr.plh_refcount 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: Anna Schumaker <Anna.Schumaker@Netapp.com>
2017-11-17 13:47:59 -05:00
Elena Reshetova
eba6dd6917 fs, nfs: convert pnfs_layout_segment.pls_refcount from atomic_t to refcount_t
refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.

Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David Windsor <dwindsor@gmail.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2017-11-17 13:47:59 -05:00