We do not want to have the state recovery thread kick off and wait for a
memory reclaim, since that may deadlock when the writebacks end up
waiting for the state recovery thread to complete.

The safe thing is therefore to use GFP_NOFS in all open, close,
delegation return, lock, etc. operations that may be called by the
state recovery thread.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

It is a BUG for anybody to call this function without setting
args->bc_xprt. Trying to return an error value is just wrong, since the
user cannot fix this: it is a programming error, not a user error.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Currently RPC performance metrics that tabulate elapsed time use
jiffies time values.  This is problematic on systems that use slow
jiffies (for instance 100HZ systems built for paravirtualized
environments).  It is also a problem for computing precise latency
statistics for advanced network transports, such as InfiniBand,
that can have round-trip latencies significanly faster than a single
clock tick.

For the RPC client, adopt the high resolution time stamp mechanism
already used by the network layer and blktrace: ktime.

We use ktime format time stamps for all internal computations, and
convert to milliseconds for presentation.  As a result, we need only
addition operations in the performance critical paths; multiply/divide
is required only for presentation.

We could report RTT metrics in microseconds.  In fact the mountstats
format is versioned to accomodate exactly this kind of interface
improvement.

For now, however, we'll stay with millisecond precision for
presentation to maintain backwards compatibility with the handful of
currently deployed user space tools.  At a later point, we'll move to
an API such as BDI_STATS where a finer timestamp precision can be
reported.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

To report ktime statistics to user space in milliseconds, a new helper
is required.

When considering how to do this conversion, I didn't immediately see
why the extra step of converting ktime to a timeval was needed.  To
make that more clear, introduce a couple of large comments.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Compute an RPC request's RTT once, and use that value both for reporting
RPC metrics, and for adjusting the RTT context used by the RPC client's RTT
estimator algorithm.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

I'm about to change task->tk_start from a jiffies value to a ktime_t
value in order to make RPC RTT reporting more precise.

Recently (commit dc96aef9) nfs4_renew_done() started to reference
task->tk_start so that a jiffies value no longer had to be passed
from nfs4_proc_async_renew().  This allowed the calldata to point to
an nfs_client instead.

Changing task->tk_start to a ktime_t value makes it effectively
useless for renew timestamps, so we need to restore the pre-dc96aef9
logic that provided a jiffies "start" timestamp to nfs4_renew_done().

Both an nfs_client pointer and a timestamp need to be passed to
nfs4_renew_done(), so create a new nfs_renewdata structure that
contains both, resembling what is already done for delegreturn,
lock, and unlock.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Clean up:

fs/nfs/iostat.h: In function ‘nfs_add_server_stats’:
fs/nfs/iostat.h:41: warning: comparison between signed and unsigned integer expressions
fs/nfs/iostat.h:41: warning: comparison between signed and unsigned integer expressions
fs/nfs/iostat.h:41: warning: comparison between signed and unsigned integer expressions
fs/nfs/iostat.h:41: warning: comparison between signed and unsigned integer expressions

Commit fce22848 replaced the open-coded per-cpu logic in several
functions in fs/nfs/iostat.h with a single invocation of
this_cpu_ptr().  This macro assumes its second argument is signed,
not unsigned.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Clean up: fscache_uniq takes a string, so it should be included
with the other string mount option definitions, by convention.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Seen with -Wextra:

/home/cel/linux/fs/nfs/fscache.c: In function ‘__nfs_readpages_from_fscache’:
/home/cel/linux/fs/nfs/fscache.c:479: warning: comparison between signed and unsigned integer expressions

The comparison implicitly converts "int" to "unsigned", making it
safe.  But there's no need for the implicit type conversions here, and
the dfprintk() already uses a "%u" formatter for "npages."  Better to
reduce confusion.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Clean up: Update the documenting comment, and fix some minor white
space issues.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Reviewed-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

If the server has given us a delegation on a file, we _know_ that we can
cache the attribute information even when the user has specified 'noac'.
Reviewed-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

We should not allow soft tasks to wait for longer than the major timeout
period when waiting for a reconnect to occur.

Remove the field xprt->connect_timeout since it has been obsoleted by
xprt->reestablish_timeout.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

This fixes a bug with setting xprt->stat.connect_start.
Reviewed-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Also have it return an ERR_PTR(-ENOMEM) instead of a null pointer.
Reviewed-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Reviewed-by: NChuck Lever <chuck.lever@oracle.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>

Use the new helper functions instead of open coding.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Keep a global count of how many referrals that the current task has
traversed on a path lookup. Return ELOOP if the count exceeds
MAX_NESTED_LINKS.
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>

Move the O_EXCL open handling into _nfs4_do_open() where it belongs. Doing
so also allows us to reuse the struct fattr from the opendata.
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>

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>

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>

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>

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