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 will allocate memory that has already been zeroed, allowing us to
remove the memset later on.
Signed-off-by: NBryan Schumaker <bjchuma@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

I put the client into an open recovery loop by:
	Client: Open file
		read half
	Server: Expire client (echo 0 > /sys/kernel/debug/nfsd/forget_clients)
	Client: Drop vm cache (echo 3 > /proc/sys/vm/drop_caches)
		finish reading file

This causes a loop because the client never updates the nfs4_state after
discovering that the delegation is invalid.  This means it will keep
trying to read using the bad delegation rather than attempting to re-open
the file.
Signed-off-by: NBryan Schumaker <bjschuma@netapp.com>
CC: stable@vger.kernel.org [3.4+]
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

If we are reading through a delegation, and the delegation is OK then
state->stateid will still point to a delegation stateid and not an open
stateid.
Signed-off-by: NBryan Schumaker <bjschuma@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Currently it does not do so if the RPC call failed to start. Fix is to
move the decrement of plh_block_lgets into nfs4_layoutreturn_release.

Also remove a redundant test of task->tk_status in nfs4_layoutreturn_done:
if lrp->res.lrs_present is set, then obviously the RPC call succeeded.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Failure of the layoutreturn allocation fails is not a good reason to
mark the pnfs_layout_hdr as having failed a layoutget or i/o. Just
exit cleanly.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

It serves no purpose that the test for whether or not we have valid
layout segments doesn't already serve.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Once all the affected layout segments have been freed up, clear the
NFS_LAYOUT_BULK_RECALL flag so that we can reuse the pnfs_layout_hdr
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

We already have a mechanism for blocking LAYOUTGET by means of the
plh_block_lgets counter. The only "service" that NFS_LAYOUT_DESTROYED
provides at this point is to block layoutget once the layout segment
list is empty, which basically means that you have to wait until
the pnfs_layout_hdr is destroyed before you can do pNFS on that file
again.

This patch enables the reuse of the pnfs_layout_hdr if the layout
segment list is empty.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

...and ditto for pnfs_free_layout_hdr()
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

These are all in static declared functions that are called only once.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Ensure that the reference count for pnfs_layout_hdr reverts to the
original value after a call to pnfs_layout_remove_lseg().

Note that the caller is expected to hold a reference to the struct
pnfs_layout_hdr.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

There is no longer a need to use pnfs_free_lseg_list(). Just call
pnfs_free_lseg() directly.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Move the code into pnfs_free_layout_hdr(), and add checks to
get_layout_by_fh_locked to ensure that they don't reference a layout
that is being freed.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

None of the existing pNFS layout drivers seem to require the inode
to be locked while they free the layout header.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Each layout segment already holds a reference to the pnfs_layout_hdr,
so there is no need to hold an extra reference that is released once
the last layout segment is freed.

Ensure that pnfs_find_alloc_layout() always returns a reference
to the pnfs_layout_hdr, which will be matched by the final call to
pnfs_put_layout_hdr() in pnfs_update_layout().
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

The latter name is more descriptive of the actual function.
Also rename pnfs_insert_layout to pnfs_layout_insert_lseg.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Instead of resetting the inode MDS threshold counters when we mark
the layout for destruction, do it as part of freeing the layout.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

In all cases where we set NFS_LAYOUT_INVALID, we also set NFS_LAYOUT_DESTROYED.
Furthermore, in all cases where we test for NFS_LAYOUT_INVALID, we should
also be testing for NFS_LAYOUT_DESTROYED, since the latter means that
we hold no valid layout segments.
Ergo the two are redundant.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Confine it to the nfs4_do_close() code.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

If we sleep after dropping the inode->i_lock, then we are no longer
atomic with respect to the rpc_wake_up() call in pnfs_layout_remove_lseg().
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

If pnfs_layout_io_test_failed() authorises a retry of the failed layoutgets,
we should clear the existing layout segments so that we start afresh. Do
this in pnfs_layout_io_set_failed().
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

We want to cache the pnfs_layout_hdr after a layoutget or i/o
failure so that pnfs_update_layout() can find it and know when
it is time to retry.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

If we exit after the call to pnfs_find_alloc_layout(), we have to ensure
that we put the struct pnfs_layout_hdr.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

In cases where the pNFS data server is just temporarily out of service,
we want to mark it as such, and then try again later. Typically that will
be in cases of network connection errors etc.
This patch allows us to mark the devices as being "unavailable" for such
transient errors, and will make them available for retries after a
2 minute timeout period.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

If we had to fall back to read/write through MDS, then assume that we should
retry pNFS after a suitable timeout period.
The following patch sets a timeout of 2 minutes.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

...and make them local to the pnfs.c file.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Dereferencing nfsi->layout in order to read plh_flags without holding
a spin lock is bug prone. Furthermore, the dprintk() tells you nothing
about whether or not the call succeeded.
Replace it with something that tells you about whether or not a valid
layout segment was returned for the inode in question.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Fix the namespace pollution issue.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

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

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

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

Ensure that we do return errors from nfs4_proc_layoutget() and that we
don't mark the layout as having failed if the error was due to a
signal or resource problem on the client side.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

This is to ensure that we don't clear the NFS_CONTEXT_RESEND_WRITES
flag while there are still writes that haven't been resent.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

If the server reboots before it can commit the unstable writes to disk,
then nfs_commit_release_pages() will detect this when it compares the
verifier returned by COMMIT to the one returned by WRITE. When this
happens, the client needs to resend those writes in order to guarantee
that they make it to stable storage.

This patch adds a signalling mechanism to notify fsync() that it
needs to retry all writes before it can exit.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

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

We want to be able to pass on the information that the page was not
dirtied under a lock. Instead of adding a flag parameter, do this
by passing a pointer to a 'struct nfs_lock_owner' that may be NULL.

Also reuse this structure in struct nfs_lock_context to carry the
fl_owner_t and pid_t.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

We want to be able to distinguish between allocation failures, and
the case where the lock context is not needed (because there are no
locks).
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

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

In nfs4_create_sec_client, 'flavor' can hold a negative error
code (returned from nfs4_negotiate_security), even though it
is an 'enum' and hence unsigned.

The code is careful to cast it to an (int) before testing if it
is negative, however it doesn't cast to an (int) before calling
ERR_PTR.

On a machine where "void*" is larger than "int", this results in
the unsigned equivalent of -1 (e.g. 0xffffffff) being converted
to a pointer.  Subsequent code determines that this is not
negative, and so  dereferences it with predictable results.

So: cast 'flavor' to a (signed) int before passing to ERR_PTR.

cc: Benny Halevy <bhalevy@tonian.com>
Signed-off-by: NNeilBrown <neilb@suse.de>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>