Currently when an alloc_page fails the error return is not set in
variable err and a garbage initialized value is returned. Fix this
by setting err to -ENOMEM before taking the error return path.

Addresses-Coverity: ("Uninitialized scalar variable")
Fixes: a1f26739 ("NFSv4.2: improve page handling for GETXATTR")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

NFSoRDmA Client updates for Linux 5.11

Cleanups and improvements:
  - Remove use of raw kernel memory addresses in tracepoints
  - Replace dprintk() call sites in ERR_CHUNK path
  - Trace unmap sync calls
  - Optimize MR DMA-unmapping
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

We have no way of tracking server READ_PLUS support in pNFS for now, so
just disable it.
Reported-by: "Mkrtchyan, Tigran" <tigran.mkrtchyan@desy.de>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

If the server returns more data than we have buffer space for, then
we need to truncate and exit early.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Expanding the READ_PLUS extents can cause the read buffer to overflow.
If it does, then don't error, but just exit early.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

If a hole extends beyond the READ_PLUS read buffer, then we want to fill
just the remaining buffer with zeros. Also ignore eof...
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

The server is allowed to return a hole extent with an offset that starts
before the offset supplied in the READ_PLUS argument. Ensure that we
support that case too.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

All XDR opaque object sizes are 32-bit aligned, and a data segment is no
exception.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

If we're shifting the page data to the right, and this happens to be a
sparse page array, then we may need to allocate new pages in order to
receive the data.
Reported-by: "Mkrtchyan, Tigran" <tigran.mkrtchyan@desy.de>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

There are a number of xdr helpers for struct xdr_buf that do not change
the structure itself. Mark those as taking const pointers for
documentation purposes.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Move the setting of the xdr_stream 'nwords' field into the helpers that
reset the xdr_stream cursor.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Clean up callers of _copy_to/from_pages() that still check for a zero
length.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Clean up xdr_shrink_bufhead() to use the new helpers instead of doing
its own thing.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

We do want to try to grow the buffer if possible, but if that attempt
fails, we still want to move the data and truncate the XDR message.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

The main use case right now for xdr_align_data() is to shift the page
data to the left, and in practice shrink the total XDR data buffer.
This patch ensures that we fix up the accounting for the buffer length
as we shift that data around.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Exit early if the shift is zero.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Use the existing BITS_PER_LONG macro instead of calculating the value.
Signed-off-by: Geliang Tang <geliangtang@gmail.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Olga K. observed that rpcrdma_marsh_req() allocates sparse pages
only when it has determined that a Reply chunk is necessary. There
are plenty of cases where no Reply chunk is needed, but the
XDRBUF_SPARSE_PAGES flag is set. The result would be a crash in
rpcrdma_inline_fixup() when it tries to copy parts of the received
Reply into a missing page.

To avoid crashing, handle sparse page allocation up front.

Until XATTR support was added, this issue did not appear often
because the only SPARSE_PAGES consumer always expected a reply large
enough to always require a Reply chunk.
Reported-by: Olga Kornievskaia <kolga@netapp.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

XDRBUF_SPARSE_PAGES can cause problems for the RDMA transport,
and it's easy enough to allocate enough pages for the request
up front, so do that.

Also, since we've allocated the pages anyway, use the full
page aligned length for the receive buffer. This will allow
caching of valid replies that are too large for the caller,
but that still fit in the allocated pages.
Signed-off-by: Frank van der Linden <fllinden@amazon.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

When receiving pages data, return value 'ret' when positive includes
`buf->page_base`, so we should subtract that before it is used for
changing `offset` and comparing against `want`.

This was discovered on the very rare cases where the server returned a
chunk of bytes that when added to the already received amount of bytes
for the pages happened to match the current `recv.len`, for example
on this case:

     buf->page_base : 258356
     actually received from socket: 1740
     ret : 260096
     want : 260096

In this case neither of the two 'if ... goto out' trigger, and we
continue to tail parsing.

Worth to mention that the ensuing EMSGSIZE from the continued execution of
`xs_read_xdr_buf` may be observed by an application due to 4 superfluous
bytes being added to the pages data.

Fixes: 277e4ab7 ("SUNRPC: Simplify TCP receive code by switching to using iterators")
Signed-off-by: Dan Aloni <dan@kernelim.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Ensure that both getxattr and listxattr page array are correctly
aligned, and that getxattr correctly accounts for the page padding word.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

nfsiod is currently a concurrency-managed workqueue (CMWQ).
This means that workitems scheduled to nfsiod on a given CPU are queued
behind all other work items queued on any CMWQ on the same CPU.  This
can introduce unexpected latency.

Occaionally nfsiod can even cause excessive latency.  If the work item
to complete a CLOSE request calls the final iput() on an inode, the
address_space of that inode will be dismantled.  This takes time
proportional to the number of in-memory pages, which on a large host
working on large files (e.g..  5TB), can be a large number of pages
resulting in a noticable number of seconds.

We can avoid these latency problems by switching nfsiod to WQ_UNBOUND.
This causes each concurrent work item to gets a dedicated thread which
can be scheduled to an idle CPU.

There is precedent for this as several other filesystems use WQ_UNBOUND
workqueue for handling various async events.
Signed-off-by: NeilBrown <neilb@suse.de>
Fixes: ada609ee ("workqueue: use WQ_MEM_RECLAIM instead of WQ_RESCUER")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

NLM uses an interval-based rebinding, i.e. it clears the transport's
binding under certain conditions if more than 60 seconds have elapsed
since the connection was last bound.

This rebinding is not necessary for an autobind RPC client over a
connection-oriented protocol like TCP.

It can also cause problems: it is possible for nlm_bind_host() to clear
XPRT_BOUND whilst a connection worker is in the middle of trying to
reconnect, after it had already been checked in xprt_connect().

When the connection worker notices that XPRT_BOUND has been cleared
under it, in xs_tcp_finish_connecting(), that results in:

	xs_tcp_setup_socket: connect returned unhandled error -107

Worse, it's possible that the two can get into lockstep, resulting in
the same behaviour repeated indefinitely, with the above error every
300 seconds, without ever recovering, and the connection never being
established. This has been seen in practice, with a large number of NLM
client tasks, following a server restart.

The existing callers of nlm_bind_host & nlm_rebind_host should not need
to force the rebind, for TCP, so restrict the interval-based rebinding
to UDP only.

For TCP, we will still rebind when needed, e.g. on timeout, and connection
error (including closure), since connection-related errors on an existing
connection, ECONNREFUSED when trying to connect, and rpc_check_timeout(),
already unconditionally clear XPRT_BOUND.

To avoid having to add the fix, and explanation, to both nlm_bind_host()
and nlm_rebind_host(), remove the duplicate code from the former, and
have it call the latter.

Drop the dprintk, which adds no value over a trace.
Signed-off-by: Calum Mackay <calum.mackay@oracle.com>
Fixes: 35f5a422 ("SUNRPC: new interface to force an RPC rebind")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

'snprintf' returns the number of characters which would have been written
if enough space had been available, excluding the terminating null byte.
Thus, the return value of 'sizeof(buf)' means that the last character
has been dropped.
Signed-off-by: Fedor Tokarev <ftokarev@gmail.com>
Fixes: 2f34b8bf ("SUNRPC: add links for all client xprts to debugfs")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

In several patches work has been done to enable NFSv4 to use user
namespaces:
58002399: NFSv4: Convert the NFS client idmapper to use the container user namespace
3b7eb5e3: NFS: When mounting, don't share filesystems between different user namespaces

Unfortunately, the userspace APIs were only such that the userspace facing
side of the filesystem (superblock s_user_ns) could be set to a non init
user namespace. This furthers the fs_context related refactoring, and
piggybacks on top of that logic, so the superblock user namespace, and the
NFS user namespace are the same.

Users can still use rpc.idmapd if they choose to, but there are complexities
with user namespaces and request-key that have yet to be addresssed.

Eventually, we will need to at least:
  * Come up with an upcall mechanism that can be triggered inside of the container,
    or safely triggered outside, with the requisite context to do the right
    mapping. * Handle whatever refactoring needs to be done in net/sunrpc.
Signed-off-by: Sargun Dhillon <sargun@sargun.me>
Tested-by: Alban Crequy <alban.crequy@gmail.com>
Fixes: 62a55d08 ("NFS: Additional refactoring for fs_context conversion")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

There was refactoring done to use the fs_context for mounting done in:
62a55d08: NFS: Additional refactoring for fs_context conversion

This made it so that the net_ns is fetched from the fs_context (the netns
that fsopen is called in). This change also makes it so that the credential
fetched during fsopen is used as well as the net_ns.

NFS has already had a number of changes to prepare it for user namespaces:
1a58e8a0: NFS: Store the credential of the mount process in the nfs_server
264d948c: NFS: Convert NFSv3 to use the container user namespace
c207db2f: NFS: Convert NFSv2 to use the container user namespace

Previously, different credentials could be used for creation of the
fs_context versus creation of the nfs_server, as FSCONFIG_CMD_CREATE did
the actual credential check, and that's where current_creds() were fetched.
This meant that the user namespace which fsopen was called in could be a
non-init user namespace. This still requires that the user that calls
FSCONFIG_CMD_CREATE has CAP_SYS_ADMIN in the init user ns.

This roughly allows a privileged user to mount on behalf of an unprivileged
usernamespace, by forking off and calling fsopen in the unprivileged user
namespace. It can then pass back that fsfd to the privileged process which
can configure the NFS mount, and then it can call FSCONFIG_CMD_CREATE
before switching back into the mount namespace of the container, and finish
up the mounting process and call fsmount and move_mount.
Signed-off-by: Sargun Dhillon <sargun@sargun.me>
Tested-by: Alban Crequy <alban.crequy@gmail.com>
Fixes: 62a55d08 ("NFS: Additional refactoring for fs_context conversion")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

When returning the layout in nfs4_evict_inode(), we need to ensure that
the layout is actually done being freed before we can proceed to free the
inode itself.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

While we always want to align to the next page and/or the beginning of
the tail buffer when we call xdr_set_next_page(), the functions
xdr_align_data() and xdr_expand_hole() really want to align to the next
object in that next page or tail.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

rpc_prepare_reply_pages() currently expects the 'hdrsize' argument to
contain the length of the data that we expect to want placed in the head
kvec plus a count of 1 word of padding that is placed after the page data.
This is very confusing when trying to read the code, and sometimes leads
to callers adding an arbitrary value of '1' just in order to satisfy the
requirement (whether or not the page data actually needs such padding).

This patch aims to clarify the code by changing the 'hdrsize' argument
to remove that 1 word of padding. This means we need to subtract the
padding from all the existing callers.

Fixes: 02ef04e4 ("NFS: Account for XDR pad of buf->pages")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Fix up xdr_read_pages() so that it can handle object lengths that are
larger than the page length, by simply aligning to the next object in
the buffer tail.
The function will continue to return the length of the truncate object
data that actually fit into the pages.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Allow xdr_set_iov() to set a base so that we can use it to set the
cursor to a specific position in the kvec buffer.

If the new base overflows the kvec/pages buffer in either xdr_set_iov()
or xdr_set_page_base(), then truncate it so that we point to the end of
the buffer.

Finally, change both function to return the number of bytes remaining to
read in their buffers.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

We already know that the head buffer and page are empty, so if there is
any data, it is in the tail.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

We can fit the device_addr4 opaque data padding in the pages.

Fixes: cf500bac ("SUNRPC: Introduce rpc_prepare_reply_pages()")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Use the existing xdr_stream_decode_string_dup() to safely decode into
kmalloced strings.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Ensure that we report the correct netid when using UDP or RDMA
transports to the DSes.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

We want to enable RDMA and UDP as valid transport methods if a
GETDEVICEINFO call specifies it. Do so by adding a parser for the
netid that translates it to an appropriate argument for the RPC
transport layer.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>