If we hold a delegation, we should not need to call
nfs_check_inode_attributes() since we already know which attributes
are valid, and which ones may still need revalidation. The state
of the NFS_INO_REVAL_FORCED flag is therefore irrelevant.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Make sure that the client completely ignores change attribute and size
changes on the server when it holds a delegation.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Don't mark attributes as invalid just because they have changed. Instead,
for the purposes of adjusting the attribute cache timeout, keep a
separate variable that tracks whether or not a change occurred.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Always try to set the attributes, even if we don't have a valid struct
nfs_fattr.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

If there are attributes that are still invalid when we set a delegation,
then we need to set the NFS_INO_REVAL_FORCED flag.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

If we hold a delegation, we don't need to care about whether or not
the inode attributes are up to date. We know we can cache the results
of this call regardless.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

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

Again, when revalidating the inode, we don't need to ask for attributes
for which we are authoritative.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Allow the getattr() callback to check things like whether or not we hold
a delegation so that it can adjust the attributes that it is asking for.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

When we hold a delegation, we should not need to request attributes such
as the file size or the change attribute. For some servers, avoiding
asking for these unneeded attributes can improve the overall system
performance.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

If the server recalls the layout that was just handed out, we risk hitting
a race as described in RFC5661 Section 2.10.6.3 unless we ensure that we
release the sequence slot after processing the LAYOUTGET operation that
was sent as part of the OPEN compound.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

If the layoutget on open call failed, we can't really commit the inode,
so don't bother calling it.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

If we're only opening the file for reading, and the file is empty and/or
we already have cached data, then heuristically optimise away the
LAYOUTGET.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Ensure that we only switch off the LAYOUTGET operation in the OPEN
compound when the server is truly broken, and/or it is complaining
that the compound is too large.
Currently, we end up turning off the functionality permanently,
even for transient errors such as EACCES or ENOSPC.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

We need to ensure that pnfs_parse_lgopen() doesn't try to parse a
struct nfs4_layoutget_res that was not filled by a successful call
to decode_layoutget(). This can happen if we performed a cached open,
or if either the OP_ACCESS or OP_GETATTR operations preceding the
OP_LAYOUTGET in the compound returned an error.

By initialising the 'status' field to NFS4ERR_DELAY, we ensure that
pnfs_parse_lgopen() won't try to interpret the structure.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

The flag was not always being cleared after LAYOUTGET on OPEN.
Signed-off-by: Fred Isaman <fred.isaman@gmail.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Since the LAYOUTGET on OPEN can be sent without prior inode information,
existing methods to prevent LAYOUTGET from being sent while processing
CB_LAYOUTRECALL don't work.  Track if a recall occurred while LAYOUTGET
was being sent, and if so ignore the results.
Signed-off-by: Fred Isaman <fred.isaman@gmail.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Signed-off-by: Fred Isaman <fred.isaman@gmail.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Signed-off-by: Fred Isaman <fred.isaman@gmail.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Move the actual freeing of the struct nfs4_layoutget into fs/nfs/pnfs.c
where it can be reused by the layoutget on open code.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

This triggers when have no pre-existing inode to attach to.
The preexisting case is saved for later.
Signed-off-by: Fred Isaman <fred.isaman@gmail.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Don't send in a layout, instead use the (possibly NULL) inode.

This is needed for LAYOUTGET attached to an OPEN where the inode is not
yet set.
Signed-off-by: Fred Isaman <fred.isaman@gmail.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

It will be needed now by the pnfs code.
Signed-off-by: Fred Isaman <fred.isaman@gmail.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Signed-off-by: Fred Isaman <fred.isaman@gmail.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

They work better in the new alloc_init function.
Signed-off-by: Fred Isaman <fred.isaman@gmail.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Pull out the alloc/init part for eventual reuse by OPEN.
Signed-off-by: Fred Isaman <fred.isaman@gmail.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Driver can set flag to allow LAYOUTGET to be sent with OPEN.
Signed-off-by: Fred Isaman <fred.isaman@gmail.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Preparing to add conditional LAYOUTGET to OPEN rpc, the LAYOUTGET
will need the ctx info.
Signed-off-by: Fred Isaman <fred.isaman@gmail.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

This will be needed to seperate return value of OPEN and LAYOUTGET
when they are combined into a single RPC.
Signed-off-by: Fred Isaman <fred.isaman@gmail.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

nfs_init_sequence() will clear this for us.
Signed-off-by: Fred Isaman <fred.isaman@gmail.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

If the wait for a LOCK operation is interrupted, and then the file is
closed, the locks cleanup code will assume that no new locks will be added
to the inode after it has completed.  We already have a mechanism to detect
if there was signal, so let's use that to avoid recreating the local lock
once the RPC completes.  Also skip re-sending the LOCK operation for the
various error cases if we were signaled.
Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
[Trond: Fix inverted test of locks_lock_inode_wait()]
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

If we get an ESTALE error in response to an RPC call operating on the
file on the MDS, we should immediately cancel the layout for that file.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

In nfs_idmap_read_and_verify_message there is an incorrect sprintf '%d'
that converts the __u32 'im_id' from struct idmap_msg to 'id_str', which
is a stack char array variable of length NFS_UINT_MAXLEN == 11.
If a uid or gid value is > 2147483647 = 0x7fffffff, the conversion
overflows into a negative value, for example:
crash> p (unsigned) (0x80000000)
$1 = 2147483648
crash> p (signed) (0x80000000)
$2 = -2147483648
The '-' sign is written to the buffer and this causes a 1 byte overflow
when the NULL byte is written, which corrupts kernel stack memory.  If
CONFIG_CC_STACKPROTECTOR_STRONG is set we see a stack-protector panic:

[11558053.616565] Kernel panic - not syncing: stack-protector: Kernel stack is corrupted in: ffffffffa05b8a8c
[11558053.639063] CPU: 6 PID: 9423 Comm: rpc.idmapd Tainted: G        W      ------------ T 3.10.0-514.el7.x86_64 #1
[11558053.641990] Hardware name: Red Hat OpenStack Compute, BIOS 1.10.2-3.el7_4.1 04/01/2014
[11558053.644462]  ffffffff818c7bc0 00000000b1f3aec1 ffff880de0f9bd48 ffffffff81685eac
[11558053.646430]  ffff880de0f9bdc8 ffffffff8167f2b3 ffffffff00000010 ffff880de0f9bdd8
[11558053.648313]  ffff880de0f9bd78 00000000b1f3aec1 ffffffff811dcb03 ffffffffa05b8a8c
[11558053.650107] Call Trace:
[11558053.651347]  [<ffffffff81685eac>] dump_stack+0x19/0x1b
[11558053.653013]  [<ffffffff8167f2b3>] panic+0xe3/0x1f2
[11558053.666240]  [<ffffffff811dcb03>] ? kfree+0x103/0x140
[11558053.682589]  [<ffffffffa05b8a8c>] ? idmap_pipe_downcall+0x1cc/0x1e0 [nfsv4]
[11558053.689710]  [<ffffffff810855db>] __stack_chk_fail+0x1b/0x30
[11558053.691619]  [<ffffffffa05b8a8c>] idmap_pipe_downcall+0x1cc/0x1e0 [nfsv4]
[11558053.693867]  [<ffffffffa00209d6>] rpc_pipe_write+0x56/0x70 [sunrpc]
[11558053.695763]  [<ffffffff811fe12d>] vfs_write+0xbd/0x1e0
[11558053.702236]  [<ffffffff810acccc>] ? task_work_run+0xac/0xe0
[11558053.704215]  [<ffffffff811fec4f>] SyS_write+0x7f/0xe0
[11558053.709674]  [<ffffffff816964c9>] system_call_fastpath+0x16/0x1b

Fix this by calling the internally defined nfs_map_numeric_to_string()
function which properly uses '%u' to convert this __u32.  For consistency,
also replace the one other place where snprintf is called.
Signed-off-by: Dave Wysochanski <dwysocha@redhat.com>
Reported-by: Stephen Johnston <sjohnsto@redhat.com>
Fixes: cf4ab538 ("NFSv4: Fix the string length returned by the idmapper")
Cc: stable@vger.kernel.org # v3.4+
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

We do not want to ignore ctime updates that originate from functions
such as link().
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

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

We may need to revalidate the change attribute, ctime and the nlinks count.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Ensure that a delegation doesn't cause us to skip initialising the inode
if it was incomplete when we exited nfs_fhget()
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Ensure that we register the fact that the inode ctime has changed.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Ensure that we pass down the inode of the file being deleted so
that we can return any delegation being held.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Even then it isn't really necessary. The reason why we may not want to
pass in a stateid in other cases is that we cannot use the delegation
credential.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>