Use xdr->nwords to tell us how much buffer remains.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

When we copy the first part of the data, we need to ensure that value
of xdr->nwords is updated as well. Do so by calling __xdr_inline_decode()
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

An xdr_buf with head[0].iov_len = 0 and page_len = 0 will cause
xdr_init_decode() to incorrectly setup the xdr_stream.  Specifically,
xdr->end is never initialized.
Signed-off-by: NBenjamin Coddington <bcodding@redhat.com>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

Mostly direct substitution with occasional adjustment or removing
outdated comments.
Signed-off-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: NMichal Hocko <mhocko@suse.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time
ago with promise that one day it will be possible to implement page
cache with bigger chunks than PAGE_SIZE.

This promise never materialized.  And unlikely will.

We have many places where PAGE_CACHE_SIZE assumed to be equal to
PAGE_SIZE.  And it's constant source of confusion on whether
PAGE_CACHE_* or PAGE_* constant should be used in a particular case,
especially on the border between fs and mm.

Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much
breakage to be doable.

Let's stop pretending that pages in page cache are special.  They are
not.

The changes are pretty straight-forward:

 - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>;

 - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>;

 - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN};

 - page_cache_get() -> get_page();

 - page_cache_release() -> put_page();

This patch contains automated changes generated with coccinelle using
script below.  For some reason, coccinelle doesn't patch header files.
I've called spatch for them manually.

The only adjustment after coccinelle is revert of changes to
PAGE_CAHCE_ALIGN definition: we are going to drop it later.

There are few places in the code where coccinelle didn't reach.  I'll
fix them manually in a separate patch.  Comments and documentation also
will be addressed with the separate patch.

virtual patch

@@
expression E;
@@
- E << (PAGE_CACHE_SHIFT - PAGE_SHIFT)
+ E

@@
expression E;
@@
- E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT)
+ E

@@
@@
- PAGE_CACHE_SHIFT
+ PAGE_SHIFT

@@
@@
- PAGE_CACHE_SIZE
+ PAGE_SIZE

@@
@@
- PAGE_CACHE_MASK
+ PAGE_MASK

@@
expression E;
@@
- PAGE_CACHE_ALIGN(E)
+ PAGE_ALIGN(E)

@@
expression E;
@@
- page_cache_get(E)
+ get_page(E)

@@
expression E;
@@
- page_cache_release(E)
+ put_page(E)
Signed-off-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: NMichal Hocko <mhocko@suse.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

A struct xdr_stream at a page boundary might point to the end of one
page or the beginning of the next, but xdr_truncate_encode isn't
prepared to handle the former.

This can cause corruption of NFSv4 READDIR replies in the case that a
readdir entry that would have exceeded the client's dircount/maxcount
limit would have ended exactly on a 4k page boundary.  You're more
likely to hit this case on large directories.

Other xdr_truncate_encode callers are probably also affected.
Reported-by: NHolger Hoffstätte <holger.hoffstaette@googlemail.com>
Tested-by: NHolger Hoffstätte <holger.hoffstaette@googlemail.com>
Fixes: 3e19ce76 "rpc: xdr_truncate_encode"
Cc: stable@vger.kernel.org
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

Reported-by: NAndrea Arcangeli <aarcange@redhat.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

Thanks to Andrea Arcangeli for pointing out these checks are
obviously unnecessary given the preceding calculations.
Reported-by: NAndrea Arcangeli <aarcange@redhat.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

Quell another sparse warning.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

The rpc code makes available to the NFS server an array of pages to
encod into.  The server represents its reply as an xdr buf, with the
head pointing into the first page in that array, the pages ** array
starting just after that, and the tail (if any) sharing any leftover
space in the page used by the head.

While encoding, we use xdr_stream->page_ptr to keep track of which page
we're currently using.

Currently we set xdr_stream->page_ptr to buf->pages, which makes the
head a weird exception to the rule that page_ptr always points to the
page we're currently encoding into.  So, instead set it to buf->pages -
1 (the page actually containing the head), and remove the need for a
little unintuitive logic in xdr_get_next_encode_buffer() and
xdr_truncate_encode.
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

With this xdr_reserve_space can help us enforce various limits.
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

After this we can handle for example getattr of very large ACLs.

Read, readdir, readlink are still special cases with their own limits.

Also we can't handle a new operation starting close to the end of a
page.
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

This will be used in the server side in a few cases:
	- when certain operations (read, readdir, readlink) fail after
	  encoding a partial response.
	- when we run out of space after encoding a partial response.
	- in readlink, where we initially reserve PAGE_SIZE bytes for
	  data, then truncate to the actual size.
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

Allow

	xdr_buf_subsegment(&buf, &buf, base, len)

to modify an xdr_buf in-place.

Also, none of the callers need the iov_base of head or tail to be zeroed
out.

Also add documentation.

(As it turns out, I'm not really using this new guarantee, but it seems
a simple way to make this function a bit more robust.)
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

Some architectures, such as ARM-32 do not return the same base address
when you call kmap_atomic() twice on the same page.
This causes problems for the memmove() call in the XDR helper routine
"_shift_data_right_pages()", since it defeats the detection of
overlapping memory ranges, and has been seen to corrupt memory.

The fix is to distinguish between the case where we're doing an
inter-page copy or not. In the former case of we know that the memory
ranges cannot possibly overlap, so we can additionally micro-optimise
by replacing memmove() with memcpy().
Reported-by: NMark Young <MYoung@nvidia.com>
Reported-by: NMatt Craighead <mcraighead@nvidia.com>
Cc: Bruce Fields <bfields@fieldses.org>
Cc: stable@vger.kernel.org
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Tested-by: NMatt Craighead <mcraighead@nvidia.com>

When GSSAPI integrity signatures are in use, or when we're using GSSAPI
privacy with the v2 token format, there is a trailing checksum on the
xdr_buf that is returned.

It's checked during the authentication stage, and afterward nothing
cares about it. Ordinarily, it's not a problem since the XDR code
generally ignores it, but it will be when we try to compute a checksum
over the buffer to help prevent XID collisions in the duplicate reply
cache.

Fix the code to trim off the checksums after verifying them. Note that
in unwrap_integ_data, we must avoid trying to reverify the checksum if
the request was deferred since it will no longer be present when it's
revisited.
Signed-off-by: NJeff Layton <jlayton@redhat.com>

Replace bounds checking BUG_ON() with a WARN_ON_ONCE() and resetting
the requested len to the max.
Signed-off-by: NWeston Andros Adamson <dros@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

We only have to call xdr_shrink_pagelen() if the remaining RPC
message does not fit in the page buffer length that we supplied
to xdr_align_pages().
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

The callers of xdr_align_pages() expect it to return the number of bytes
of actual XDR data remaining in the pages.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Fix incorrect start markers, wrapped summary lines, missing section
breaks, incorrect separators, and some name mismatches.
Signed-off-by: NBen Hutchings <bhutchings@solarflare.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Use the xdr_align_pages() helper
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Move the page alignment code into a separate helper.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Use xdr_stream_pos() instead.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Add a helper to report the current offset from the start of the
xdr_stream.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Callers of xdr_read_pages() will want to know exactly how much XDR
data is encoded in the pages after the data realignment.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Now that xdr_inline_decode() will automatically cross into the page
buffers, we need to ensure that it doesn't exceed the total reply
message length.

This patch sets up a counter that tracks the number of words
remaining in the reply message, and ensures that xdr_inline_decode,
xdr_read_pages and xdr_enter_page respect the end of message boundary.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Remove the 'p' argument, since that is only ever set by xdr_init_decode.
Add sanity checking of 'p' inside xdr_init_decode itself.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Use of "unsigned int" is preferred to bare "unsigned" in net tree.
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NCong Wang <amwang@redhat.com>

The NFSv4 bitmap size is unbounded: a server can return an arbitrary
sized bitmap in an FATTR4_WORD0_ACL request.  Replace using the
nfs4_fattr_bitmap_maxsz as a guess to the maximum bitmask returned by a server
with the inclusion of the bitmap (xdr length plus bitmasks) and the acl data
xdr length to the (cached) acl page data.

This is a general solution to commit e5012d1f "NFSv4.1: update
nfs4_fattr_bitmap_maxsz" and fixes hitting a BUG_ON in xdr_shrink_bufhead
when getting ACLs.

Fix a bug in decode_getacl that returned -EINVAL on ACLs > page when getxattr
was called with a NULL buffer, preventing ACL > PAGE_SIZE from being retrieved.

Cc: stable@kernel.org
Signed-off-by: NAndy Adamson <andros@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Ensure that the backchannel exports conform to the existing sunrpc
practice.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Initialize xdr_stream and xdr_buf using an array of page pointers
and length of buffer.
Signed-off-by: NBenny Halevy <bhalevy@panasas.com>

vm_map_ram() is not available on NOMMU platforms, and causes trouble
on incoherrent architectures such as ARM when we access the page data
through both the direct and the virtual mapping.

The alternative is to use the direct mapping to access page data
for the case when we are not crossing a page boundary, but to copy
the data into a linear scratch buffer when we are accessing data
that spans page boundaries.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Tested-by: NMarc Kleine-Budde <mkl@pengutronix.de>
Cc: stable@kernel.org  [2.6.37]

We sometimes need to be able to read ahead in an xdr_stream without
incrementing the current pointer position.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Clean up: Introduce a helper to '\0'-terminate XDR strings
that are placed in a page in the page cache.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

If we have unused buffer space, then we should make use of that rather
than unnecessarily truncating the message.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

The "copy" variable value can be computed using the existing
logic rather than repeating it.
Signed-off-by: NBenny Halevy <bhalevy@panasas.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>