The following set of operations on a NFS client and server will cause

    server# mkdir a
    client# cd a
    server# mv a a.bak
    client# sleep 30  # (or whatever the dir attrcache timeout is)
    client# stat .
    stat: cannot stat `.': Stale NFS file handle

Obviously, we should not be getting an ESTALE error back there since the
inode still exists on the server. The problem is that the lookup code
will call d_revalidate on the dentry that "." refers to, because NFS has
FS_REVAL_DOT set.

nfs_lookup_revalidate will see that the parent directory has changed and
will try to reverify the dentry by redoing a LOOKUP. That of course
fails, so the lookup code returns ESTALE.

The problem here is that d_revalidate is really a bad fit for this case.
What we really want to know at this point is whether the inode is still
good or not, but we don't really care what name it goes by or whether
the dcache is still valid.

Add a new d_op->d_weak_revalidate operation and have complete_walk call
that instead of d_revalidate. The intent there is to allow for a
"weaker" d_revalidate that just checks to see whether the inode is still
good. This is also gives us an opportunity to kill off the FS_REVAL_DOT
special casing.

[AV: changed method name, added note in porting, fixed confusion re
having it possibly called from RCU mode (it won't be)]

Cc: NeilBrown <neilb@suse.de>
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

nfs_open_permission_mask() should only check MAY_EXEC for files that
are opened with __FMODE_EXEC.

Also fix NFSv4 access-in-open path in a similar way -- openflags must be
used because fmode will not always have FMODE_EXEC set.

This patch fixes https://bugzilla.kernel.org/show_bug.cgi?id=49101Signed-off-by: NWeston Andros Adamson <dros@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org

But the kernel decided to call it "origin" instead.  Fix most of the
sites.
Acked-by: NHugh Dickins <hughd@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

If the inode has no links, then we should force a new lookup.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

It is almost always wrong for NFS to call drop_nlink() after removing a
file. What we really want is to mark the inode's attributes for
revalidation, and we want to ensure that the VFS drops it if we're
reasonably sure that this is the final unlink().
Do the former using the usual cache validity flags, and the latter
by testing if inode->i_nlink == 1, and clearing it in that case.

This also fixes the following warning reported by Neil Brown and
Jeff Layton (among others).

[634155.004438] WARNING:
at /home/abuild/rpmbuild/BUILD/kernel-desktop-3.5.0/lin [634155.004442]
Hardware name: Latitude E6510 [634155.004577]  crc_itu_t crc32c_intel
snd_hwdep snd_pcm snd_timer snd soundcor [634155.004609] Pid: 13402, comm:
bash Tainted: G        W    3.5.0-36-desktop # [634155.004611] Call Trace:
[634155.004630]  [<ffffffff8100444a>] dump_trace+0xaa/0x2b0
[634155.004641]  [<ffffffff815a23dc>] dump_stack+0x69/0x6f
[634155.004653]  [<ffffffff81041a0b>] warn_slowpath_common+0x7b/0xc0
[634155.004662]  [<ffffffff811832e4>] drop_nlink+0x34/0x40
[634155.004687]  [<ffffffffa05bb6c3>] nfs_dentry_iput+0x33/0x70 [nfs]
[634155.004714]  [<ffffffff8118049e>] dput+0x12e/0x230
[634155.004726]  [<ffffffff8116b230>] __fput+0x170/0x230
[634155.004735]  [<ffffffff81167c0f>] filp_close+0x5f/0x90
[634155.004743]  [<ffffffff81167cd7>] sys_close+0x97/0x100
[634155.004754]  [<ffffffff815c3b39>] system_call_fastpath+0x16/0x1b
[634155.004767]  [<00007f2a73a0d110>] 0x7f2a73a0d10f
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org [3.3+]

We are leaking fattr and fhandle if we decide that dentry is not to
be invalidated, after all (e.g. happens to be a mountpoint).  Just
free both before that...
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

The OPEN operation has no way to differentiate an open for read and an
open for execution - both look like read to the server. This allowed
users to read files that didn't have READ access but did have EXEC access,
which is obviously wrong.

This patch adds an ACCESS call to the OPEN compound to handle the
difference between OPENs for reading and execution.  Since we're going
through the trouble of calling ACCESS, we check all possible access bits
and cache the results hopefully avoiding an ACCESS call in the future.
Signed-off-by: NWeston Andros Adamson <dros@netapp.com>
Signed-off-by: NTrond 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: NBryan Schumaker <bjschuma@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

This patch exports symbols and moves over the final structures needed by
the v3 module.  In addition, I also switch over to using IS_ENABLED() to
check if CONFIG_NFS_V3 or CONFIG_NFS_V3_MODULE are set.

The module (nfs3.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 v3.
Signed-off-by: NBryan Schumaker <bjschuma@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

The module (nfs2.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 v2.
Signed-off-by: NBryan Schumaker <bjschuma@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

The NFS v4 file inode operations are already already in nfs4proc.c, so
this patch just needs to move the directory operations to the same file.
Signed-off-by: NBryan Schumaker <bjschuma@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

This patch moves the NFS v3 file and directory inode functions into
files that are only compiled whet CONFIG_NFS_V3 is enabled.
Signed-off-by: NBryan Schumaker <bjschuma@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

This patch moves the NFS v2 file and directory inode functions into
files that are only compiled whet CONFIG_NFS_V2 is enabled.
Signed-off-by: NBryan Schumaker <bjschuma@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

boolean "does it have to be exclusive?" flag is passed instead;
Local filesystem should just ignore it - the object is guaranteed
not to be there yet.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Just the flags; only NFS cares even about that, but there are
legitimate uses for such argument.  And getting rid of that
completely would require splitting ->lookup() into a couple
of methods (at least), so let's leave that alone for now...
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Just the lookup flags.  Die, bastard, die...
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

just pass the flags
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

namely, 1 ;-)  That's what we want to return from ->atomic_open()
instances after finish_no_open().
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Just pass struct file *.  Methods are happier that way...
There's no need to return struct file * from finish_open() now,
so let it return int.  Next: saner prototypes for parts in
namei.c
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Change of calling conventions:
old		new
NULL		1
file		0
ERR_PTR(-ve)	-ve

Caller *knows* that struct file *; no need to return it.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

... and let finish_open() report having opened the file via that sucker.
Next step: don't modify od->filp at all.

[AV: FILE_CREATE was already used by cifs; Miklos' fix folded]
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

is_atomic_open() is now only used by nfs4_lookup_revalidate() to check whether
it's okay to skip normal revalidation.

It does a racy check for mount read-onlyness and falls back to normal
revalidation if the open would fail.  This makes little sense now that this
function isn't used for determining whether to actually open the file or not.

The d_mountpoint() check still makes sense since it is an indication that we
might be following a mount and so open may not revalidate the dentry.
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>
CC: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Instead check LOOKUP_EXCL in nd->flags, which is basically what the open intent
flags were used for.
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>
CC: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Don't pass nfs_open_context() to ->create().  Only the NFS4 implementation
needed that and only because it wanted to return an open file using open
intents.  That task has been replaced by ->atomic_open so it is not necessary
anymore to pass the context to the create rpc operation.

Despite nfs4_proc_create apparently being okay with a NULL context it Oopses
somewhere down the call chain.  So allocate a context here.
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>
CC: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Replace NFS4 specific ->lookup implementation with ->atomic_open impelementation
and use the generic nfs_lookup for other lookups.
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>
CC: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

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

Delegations are a v4 feature, so push them out of the generic code.
Signed-off-by: NBryan Schumaker <bjschuma@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

NFSv4 can't do reliable opens in d_revalidate, since it cannot know whether a
mount needs to be followed or not.  It does check d_mountpoint() on the dentry,
which can result in a weird error if the VFS found that the mount does not in
fact need to be followed, e.g.:

  # mount --bind /mnt/nfs /mnt/nfs-clone
  # echo something > /mnt/nfs/tmp/bar
  # echo x > /tmp/file
  # mount --bind /tmp/file /mnt/nfs-clone/tmp/bar
  # cat  /mnt/nfs/tmp/bar
  cat: /mnt/nfs/tmp/bar: Not a directory

Which should, by any sane filesystem, result in "something" being printed.

So instead do the open in f_op->open() and in the unlikely case that the cached
dentry turned out to be invalid, drop the dentry and return EOPENSTALE to let
the VFS retry.
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>
CC: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

This allows comparing hash and len in one operation on 64-bit
architectures.  Right now only __d_lookup_rcu() takes advantage of this,
since that is the case we care most about.

The use of anonymous struct/unions hides the alternate 64-bit approach
from most users, the exception being a few cases where we initialize a
'struct qstr' with a static initializer.  This makes the problematic
cases use a new QSTR_INIT() helper function for that (but initializing
just the name pointer with a "{ .name = xyzzy }" initializer remains
valid, as does just copying another qstr structure).
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

While the use of READDIRPLUS is significantly more efficient than
READDIR followed by many LOOKUP calls, it is still less efficient
than just READDIR if the attributes are not required.

This patch tracks when lookups are attempted on the directory,
and uses that information to selectively disable READDIRPLUS
on that directory.
The first 'readdir' call is always served using READDIRPLUS.
Subsequent calls only use READDIRPLUS if there was a successful
lookup or revalidation on a child in the mean time.

Credit for the original idea should go to Neil Brown. See:
      http://www.spinics.net/lists/linux-nfs/msg19996.html
However, the implementation in this patch differs from Neil's
in that it focuses on tracking lookups rather than calls to
stat().
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Cc: Neil Brown <neilb@suse.de>

Now that I'm doing secinfo automatically in the v4 code this extra
argument isn't needed.
Signed-off-by: NBryan Schumaker <bjschuma@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

If the file wasn't opened for writing, then truncate and ftruncate
need to report the appropriate errors.
Reported-by: NMiklos Szeredi <miklos@szeredi.hu>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org

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

Eliminate a number of implicit type casts in comparisons, and these
compiler warnings:

fs/nfs/dir.c: In function ‘nfs_readdir_clear_array’:
fs/nfs/dir.c:264:16: warning: comparison between signed and unsigned
		integer expressions [-Wsign-compare]
fs/nfs/dir.c: In function ‘nfs_readdir_search_for_cookie’:
fs/nfs/dir.c:352:16: warning: comparison between signed and unsigned
		integer expressions [-Wsign-compare]
fs/nfs/dir.c: In function ‘nfs_do_filldir’:
fs/nfs/dir.c:769:38: warning: comparison between signed and unsigned
		integer expressions [-Wsign-compare]
fs/nfs/dir.c:780:9: warning: comparison between signed and unsigned
		integer expressions [-Wsign-compare]
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Currently, we will correctly optimise away a truncate that doesn't
change the file size. However, in the case of open(O_TRUNC), we
also want to optimise away the time changes.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>