It is frequently useful to sync a single file system, instead of all
mounted file systems via sync(2):

 - On machines with many mounts, it is not at all uncommon for some of
   them to hang (e.g. unresponsive NFS server).  sync(2) will get stuck on
   those and may never get to the one you do care about (e.g., /).
 - Some applications write lots of data to the file system and then
   want to make sure it is flushed to disk.  Calling fsync(2) on each
   file introduces unnecessary ordering constraints that result in a large
   amount of sub-optimal writeback/flush/commit behavior by the file
   system.

There are currently two ways (that I know of) to sync a single super_block:

 - BLKFLSBUF ioctl on the block device: That also invalidates the bdev
   mapping, which isn't usually desirable, and doesn't work for non-block
   file systems.
 - 'mount -o remount,rw' will call sync_filesystem as an artifact of the
   current implemention.  Relying on this little-known side effect for
   something like data safety sounds foolish.

Both of these approaches require root privileges, which some applications
do not have (nor should they need?) given that sync(2) is an unprivileged
operation.

This patch introduces a new system call syncfs(2) that takes an fd and
syncs only the file system it references.  Maybe someday we can

 $ sync /some/path

and not get

 sync: ignoring all arguments

The syscall is motivated by comments by Al and Christoph at the last LSF.
syncfs(2) seems like an appropriate name given statfs(2).

A similar ioctl was also proposed a while back, see
	http://marc.info/?l=linux-fsdevel&m=127970513829285&w=2Signed-off-by: NSage Weil <sage@newdream.net>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

A syscall was added without being added to asm-generic, which
makes tile (and presumably score and unicore32) break.
Signed-off-by: NChris Metcalf <cmetcalf@tilera.com>
Acked-by: NArnd Bergmann <arnd@arndb.de>
Cc: Guan Xuetao <gxt@mprc.pku.edu.cn>
Cc: Chen Liqin <liqin.chen@sunplusct.com>
Cc: Lennox Wu <lennox.wu@gmail.com>

Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Signed-off-by: NChris Metcalf <cmetcalf@tilera.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Acked-by: NArnd Bergmann <arnd@arndb.de>
Cc: Eric Paris <eparis@redhat.com>

Add __NR_prlimit64 syscall numbers to asm-generic. Add them also to
asm-x86, both 32 and 64-bit.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>

The initial pass at the generic ABI assumed that wait4() could be
easily expressed using waitid().  Although it's true that wait4()
can be built on waitid(), it's awkward enough that it makes more
sense to continue to include wait4 in the generic syscall ABI.

Since there is already a deprecated wait4 in the ABI, this change
converts that wait4 into old_wait, and puts wait4 in the next
available slot for new supported syscalls, after the platform-specific
syscalls at number 260.
Signed-off-by: NChris Metcalf <cmetcalf@tilera.com>
Acked-by: NArnd Bergmann <arnd@arndb.de>

Reserve 16 "architecture-specific" syscall numbers starting at 244.

Allow use of the sys_sync_file_range2() API with the generic unistd.h
by specifying __ARCH_WANT_SYNC_FILE_RANGE2 before including it.

Allow using the generic unistd.h to create the "compat" syscall table
by specifying __SYSCALL_COMPAT before including it.

Use sys_fadvise64_64 for __NR3264_fadvise64 in both 32- and 64-bit mode.

Request the appropriate __ARCH_WANT_COMPAT_SYS_xxx values when
some deprecated syscall modes are selected.

As part of this change to fix up the syscalls, also provide a couple
of missing signal-related syscall prototypes in <linux/syscalls.h>.
Signed-off-by: NChris Metcalf <cmetcalf@tilera.com>
Acked-by: NArnd Bergmann <arnd@arndb.de>

sys_recvmmsg was recently merged, add it to asm-generic
as well so new architectures can use it.
Signed-off-by: NArnd Bergmann <arnd@arndb.de>

Code review has shown that the generic version of
unistd.h is missing a reference to the accept4
system call. This was not noticed before because
most architectures handle this through sys_socketcall.
Signed-off-by: NArnd Bergmann <arnd@arndb.de>

That is "success", "unknown", "through", "performance", "[re|un]mapping"
, "access", "default", "reasonable", "[con]currently", "temperature"
, "channel", "[un]used", "application", "example","hierarchy", "therefore"
, "[over|under]flow", "contiguous", "threshold", "enough" and others.
Signed-off-by: NAndré Goddard Rosa <andre.goddard@gmail.com>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>

>>From 9741f7928ef35416e49f329a64e623a109de5c2d Mon Sep 17 00:00:00 2001
From: Chen Liqin <liqin.chen@sunplusct.com>
Date: Mon, 26 Oct 2009 10:50:50 +0800
Subject: [PATCH] asm-generic: Fix typo in asm-generic/unistd.h.

Fixed __NR_ftruncate and __NR_ftruncate64 define in asm-generic/unistd.h.
Signed-off-by: NChen Liqin <liqin.chen@sunplusct.com>
Signed-off-by: NArnd Bergmann <arnd@arndb.de>

Bye-bye Performance Counters, welcome Performance Events!

In the past few months the perfcounters subsystem has grown out its
initial role of counting hardware events, and has become (and is
becoming) a much broader generic event enumeration, reporting, logging,
monitoring, analysis facility.

Naming its core object 'perf_counter' and naming the subsystem
'perfcounters' has become more and more of a misnomer. With pending
code like hw-breakpoints support the 'counter' name is less and
less appropriate.

All in one, we've decided to rename the subsystem to 'performance
events' and to propagate this rename through all fields, variables
and API names. (in an ABI compatible fashion)

The word 'event' is also a bit shorter than 'counter' - which makes
it slightly more convenient to write/handle as well.

Thanks goes to Stephane Eranian who first observed this misnomer and
suggested a rename.

User-space tooling and ABI compatibility is not affected - this patch
should be function-invariant. (Also, defconfigs were not touched to
keep the size down.)

This patch has been generated via the following script:

  FILES=$(find * -type f | grep -vE 'oprofile|[^K]config')

  sed -i \
    -e 's/PERF_EVENT_/PERF_RECORD_/g' \
    -e 's/PERF_COUNTER/PERF_EVENT/g' \
    -e 's/perf_counter/perf_event/g' \
    -e 's/nb_counters/nb_events/g' \
    -e 's/swcounter/swevent/g' \
    -e 's/tpcounter_event/tp_event/g' \
    $FILES

  for N in $(find . -name perf_counter.[ch]); do
    M=$(echo $N | sed 's/perf_counter/perf_event/g')
    mv $N $M
  done

  FILES=$(find . -name perf_event.*)

  sed -i \
    -e 's/COUNTER_MASK/REG_MASK/g' \
    -e 's/COUNTER/EVENT/g' \
    -e 's/\<event\>/event_id/g' \
    -e 's/counter/event/g' \
    -e 's/Counter/Event/g' \
    $FILES

... to keep it as correct as possible. This script can also be
used by anyone who has pending perfcounters patches - it converts
a Linux kernel tree over to the new naming. We tried to time this
change to the point in time where the amount of pending patches
is the smallest: the end of the merge window.

Namespace clashes were fixed up in a preparatory patch - and some
stylistic fallout will be fixed up in a subsequent patch.

( NOTE: 'counters' are still the proper terminology when we deal
  with hardware registers - and these sed scripts are a bit
  over-eager in renaming them. I've undone some of that, but
  in case there's something left where 'counter' would be
  better than 'event' we can undo that on an individual basis
  instead of touching an otherwise nicely automated patch. )
Suggested-by: NStephane Eranian <eranian@google.com>
Acked-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: NPaul Mackerras <paulus@samba.org>
Reviewed-by: NArjan van de Ven <arjan@linux.intel.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: David Howells <dhowells@redhat.com>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: <linux-arch@vger.kernel.org>
LKML-Reference: <new-submission>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

sys_rt_tgsigqueueinfo and sys_perf_counter_open
have been added in 2.6.31, so hook them up in the
generic unistd.h file.

Since the file is now in the mainline kernel, we
are no longer reordering the numbers but just add
system calls at the end.
Signed-off-by: NArnd Bergmann <arnd@arndb.de>

A new architecture should only define a minimal set of system
calls while still providing the full functionality. This version
of unistd.h has gone through intensive review to make sure that
by default it only enables syscalls that do not already have
a more featureful replacement.

It is modeled after the x86-64 version of unistd.h, which unifies
the syscall number definition and the actual system call table
in a single file, in order to keep them synchronized much more
easily.

This first version still keeps legacy system call definitions
around, guarded by various #ifdefs, and with numbers larger
than 1024. The idea behind this is to make it easier for
new architectures to transition from a full list to the reduced
set. In particular, the new microblaze architecture that should
migrate to using the generic ABI headers can at least use an
existing uClibc source tree without major rewrites during the
conversion.
Signed-off-by: NArnd Bergmann <arnd@arndb.de>