If an iptables drop rule is added for an nfs server, the client can end up in
a softlockup. Because of the way that xs_sendpages() is structured, the -EPERM
is ignored since the prior bits of the packet may have been successfully queued
and thus xs_sendpages() returns a non-zero value. Then, xs_udp_send_request()
thinks that because some bits were queued it should return -EAGAIN. We then try
the request again and again, resulting in cpu spinning. Reproducer:

1) open a file on the nfs server '/nfs/foo' (mounted using udp)
2) iptables -A OUTPUT -d <nfs server ip> -j DROP
3) write to /nfs/foo
4) close /nfs/foo
5) iptables -D OUTPUT -d <nfs server ip> -j DROP

The softlockup occurs in step 4 above.

The previous patch, allows xs_sendpages() to return both a sent count and
any error values that may have occurred. Thus, if we get an -EPERM, return
that to the higher level code.

With this patch in place we can successfully abort the above sequence and
avoid the softlockup.

I also tried the above test case on an nfs mount on tcp and although the system
does not softlockup, I still ended up with the 'hung_task' firing after 120
seconds, due to the i/o being stuck. The tcp case appears a bit harder to fix,
since -EPERM appears to get ignored much lower down in the stack and does not
propogate up to xs_sendpages(). This case is not quite as insidious as the
softlockup and it is not addressed here.
Reported-by: NYigong Lou <ylou@akamai.com>
Signed-off-by: NJason Baron <jbaron@akamai.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

If an error is returned after the first bits of a packet have already been
successfully queued, xs_sendpages() will return a positive 'int' value
indicating success. Callers seem to treat this as -EAGAIN.

However, there are cases where its not a question of waiting for the write
queue to drain. For example, when there is an iptables rule dropping packets
to the destination, the lower level code can return -EPERM only after parts
of the packet have been successfully queued. In this case, we can end up
continuously retrying resulting in a kernel softlockup.

This patch is intended to make no changes in behavior but is in preparation for
subsequent patches that can make decisions based on both on the number of bytes
sent by xs_sendpages() and any errors that may have be returned.
Signed-off-by: NJason Baron <jbaron@akamai.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

If rpc.statd is restarted, upcalls to monitor hosts can fail with
ECONNREFUSED.  In that case force a lookup of statd's new port and retry the
upcall.
Signed-off-by: NBenjamin Coddington <bcodding@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

When aborting a connection to preserve source ports, don't wake the task in
xs_error_report.  This allows tasks with RPC_TASK_SOFTCONN to succeed if the
connection needs to be re-established since it preserves the task's status
instead of setting it to the status of the aborting kernel_connect().

This may also avoid a potential conflict on the socket's lock.
Signed-off-by: NBenjamin Coddington <bcodding@redhat.com>
Cc: stable@vger.kernel.org # 3.14+
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Commit c9fdeb28 removed a 'continue' after checking if the lease needs
to be renewed. However, if client hasn't moved, the code falls down to
starting reboot recovery erroneously (ie., sends open reclaim and gets
back stale_clientid error) before recovering from getting stale_clientid
on the renew operation.
Signed-off-by: NOlga Kornievskaia <kolga@netapp.com>
Fixes: c9fdeb28 (NFS: Add basic migration support to state manager thread)
Cc: stable@vger.kernel.org # 3.13+
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

kbuild test robot reports:

   fs/built-in.o: In function `bl_map_stripe':
   >> :(.text+0x965b4): undefined reference to `__aeabi_uldivmod'
   >> :(.text+0x965cc): undefined reference to `__aeabi_uldivmod'
   >> :(.text+0x96604): undefined reference to `__aeabi_uldivmod'

Fixes: 5c83746a (pnfs/blocklayout: in-kernel GETDEVICEINFO XDR parsing)
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Christoph Hellwig <hch@lst.de>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Signed-off-by: NStephen Rothwell <sfr@canb.auug.org.au>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Both blocks layout and objects layout want to use it to avoid CB_LAYOUTRECALL
but that should only happen if client is doing truncation to a smaller size.
For other cases, we let server decide if it wants to recall client's layouts.
Change PNFS_LAYOUTRET_ON_SETATTR to follow the logic and not to send
layoutreturn unnecessarily.

Cc: Christoph Hellwig <hch@lst.de>
Cc: Boaz Harrosh <boaz@plexistor.com>
Signed-off-by: NPeng Tao <tao.peng@primarydata.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

This code is internal to the v3 module, so other parts of the client
shouldn't have any knowledge of it.

nfs3_getxattr(), nfs3_setxattr(), and nfs3_removexattr() no longer exist
anywhere so I remove the declarations while I'm here.
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

This check is already performed by the module loading code - if the
module can't be found then -EPROTONOSUPPORT will be returned.  Let's
handle v3 this way, too.
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

I am generally against the "one big header file" approach, and
everything in the client includes this file.  Let's move all the NFS v3
declarations into a v3-only header file.
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

The goal is to create a generic NFS module with code that does not
depend on what versions of NFS are enabled.
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

This code has been around for a while, but never was enabled, although
it is in a working shape.

Note that we implement NOTIFY_DEVICEID4_CHANGE identical to
NOTIFY_DEVICEID4_DELETE.  Given that in either case we can't do anything
but preventing further lookups of a given device ID there isn't much difference
in semantics for the two.  For the delete case the server MUST ensure that
there are no outstanding layouts, while for the change case it doesn't, but
that has little relevance to the client.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

This patches moves parsing of the GETDEVICEINFO XDR to kernel space, as well
as the management of complex devices.  The reason for that is we might have
multiple outstanding complex devices after a NOTIFY_DEVICEID4_CHANGE, which
device mapper or md can't handle as they claim devices exclusively.

But as is turns out simple striping / concatenation is fairly trivial to
implement anyway, so we make our life simpler by reducing the reliance
on blkmapd.  For now we still use blkmapd by feeding it synthetic SIMPLE
device XDR to translate device signatures to device numbers, but in the
long runs I have plans to eliminate it entirely.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Create a file to house all the rpc_pipefs boilerplate code instead of
sprinkling it over a few files.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Factor out a helper for all per-extent work, and merge the now trivial
functions for lseg allocation and parsing.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

This isn't device(id) related, so move it into the main file.  Simple move
for now, the next commit will clean it up a bit.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Instead of overflowing the XDR send buffer with our extent list allocate
pages and pre-encode the layoutupdate payload into them.  We optimistically
allocate a single page use alloc_page and only switch to vmalloc when we
have more extents outstanding.  Currently there is only a single testcase
(xfstests generic/113) which can reproduce large enough extent lists for
this to occur.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

The current GETDEVICELIST implementation is buggy in that it doesn't handle
cursors correctly, and in that it returns an error if the server returns
NFSERR_NOTSUPP.  Given that there is no actual need for GETDEVICELIST,
it has various issues and might get removed for NFSv4.2 stop using it in
the blocklayout driver, and thus the Linux NFS client as whole.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

The kbuild test robot complained about a new sparse warning in
objio_alloc_deviceid_node, but it turns out that this was just a moved
reference to an existing variable.  Fix it to have the right big endian
annotated type.

Note that there are some other endianess issues in this file that I didn't
bother to sort out as they involve global headers.
Reported-by: Nkbuild test robot <fengguang.wu@intel.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

The kbuild test robot complained that we got the printk format wrong.
Let's just kill these printks instead of fixing them as there is not
point after the initial tree algorithm debugging.
Reported-by: Nkbuild test robot <fengguang.wu@intel.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

To make sparse happy...
Signed-off-by: NJeff Layton <jlayton@primarydata.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

sparse says:

fs/nfs/file.c:543:60: warning: incorrect type in argument 1 (different address spaces)
fs/nfs/file.c:543:60:    expected struct rpc_xprt *xprt
fs/nfs/file.c:543:60:    got struct rpc_xprt [noderef] <asn:4>*cl_xprt
fs/nfs/file.c:548:53: warning: incorrect type in argument 1 (different address spaces)
fs/nfs/file.c:548:53:    expected struct rpc_xprt *xprt
fs/nfs/file.c:548:53:    got struct rpc_xprt [noderef] <asn:4>*cl_xprt

cl_xprt is RCU-managed, so we need to take care to dereference and use
it while holding the RCU read lock.

Cc: Mel Gorman <mgorman@suse.de>
Signed-off-by: NJeff Layton <jlayton@primarydata.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

The VFS never calls setattr with ATTR_SIZE on anything but regular
files.  Remove the if check and turn it into an assert similar to
what some other file systems do.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

This will be used by the block layout driver when splitting extents.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

At a simple helper to issue a GETDEVICELIST operation and pre-load
the device id cache based on the result.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Add support to the common pNFS core to issue GETDEVICEINFO calls on
a device ID cache miss.  The code is taken from the well debugged
file layout implementation and calls out to the layoutdriver through
a new alloc_deviceid_node method.  The calling conventions for
nfs4_find_get_deviceid are changed so that all information needed to
send a GETDEVICEINFO request is passed to the common code.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

This speads up truncate-heavy workloads like fsx by multiple orders of
magnitude.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

This allows removing extents from the extent tree especially on truncate
operations, and thus fixing reads from truncated and re-extended that
previously returned stale data.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Currently the block layout driver tracks extents in three separate
data structures:

 - the two list of pnfs_block_extent structures returned by the server
 - the list of sectors that were in invalid state but have been written to
 - a list of pnfs_block_short_extent structures for LAYOUTCOMMIT

All of these share the property that they are not only highly inefficient
data structures, but also that operations on them are even more inefficient
than nessecary.

In addition there are various implementation defects like:

 - using an int to track sectors, causing corruption for large offsets
 - incorrect normalization of page or block granularity ranges
 - insufficient error handling
 - incorrect synchronization as extents can be modified while they are in
   use

This patch replace all three data with a single unified rbtree structure
tracking all extents, as well as their in-memory state, although we still
need to instance for read-only and read-write extent due to the arcane
client side COW feature in the block layouts spec.

To fix the problem of extent possibly being modified while in use we make
sure to return a copy of the extent for use in the write path - the
extent can only be invalidated by a layout recall or return which has
to wait until the I/O operations finished due to refcounts on the layout
segment.

The new extent tree work similar to the schemes used by block based
filesystems like XFS or ext4.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

The core nfs code handles setting pages uptodate on reads, no need to mess
with the pageflags outselves.  Also remove a debug function to dump page
flags.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Use the new PNFS_READ_WHOLE_PAGE flag to offload read-modify-write
handling to core nfs code, and remove a huge chunk of deadlock prone
mess from the block layout writeback path.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

If a layout driver keeps per-inode state outside of the layout segments it
needs to be notified of any layout returns or recalls on an inode, and not
just about the freeing of layout segments.  Add a method to acomplish this,
which will allow the block layout driver to handle the case of truncated
and re-expanded files properly.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Like all block based filesystems, the pNFS block layout driver can't read
or write at a byte granularity and thus has to perform read-modify-write
cycles on writes smaller than this granularity.

Add a flag so that the core NFS code always reads a whole page when
starting a smaller write, so that we can do it in the place where the VFS
expects it instead of doing in very deadlock prone way in the writeback
handler.

Note that in theory we could do less than page size reads here for disks
that have a smaller sector size which are served by a server with a smaller
pnfs block size.  But so far that doesn't seem like a worthwhile
optimization.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Expedite layout recall processing by forcing a layout commit when
we see busy segments.  Without it the layout recall might have to wait
until the VM decided to start writeback for the file, which can introduce
long delays.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

gcc reports:

linux/fs/nfs/write.c: In function ‘nfs_page_find_head_request_locked.isra.17’:
linux/fs/nfs/write.c:121:64: warning: ‘cinfo.mds’ may be used uninitialized in this function [-Wmaybe-uninitialized]
  list_for_each_entry_safe(freq, t, &cinfo.mds->list, wb_list) {
                                                                  ^
linux/fs/nfs/write.c:110:25: note: ‘cinfo.mds’ was declared here
  struct nfs_commit_info cinfo;
Reported-by: NAnna Schumaker <Anna.Schumaker@netapp.com>
Cc: Weston Andros Adamson <dros@primarydata.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

When we do non-page sized reads we can underflow the extent_length variable
and read incorrect data.  Fix the extent_length calculation and change to
defensive <= checks for the extent length in the read and write path.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Make sure the block queue is plugged when performing pNFS blocklayout I/O.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>