fs/Kconfig


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#
# File system configuration
#

menu "File systems"

# Use unaligned word dcache accesses
config DCACHE_WORD_ACCESS
       bool

if BLOCK

source "fs/ext2/Kconfig"
source "fs/ext3/Kconfig"
source "fs/ext4/Kconfig"
source "fs/jbd/Kconfig"
source "fs/jbd2/Kconfig"

config FS_MBCACHE
# Meta block cache for Extended Attributes (ext2/ext3/ext4)
	tristate
	default y if EXT2_FS=y && EXT2_FS_XATTR
	default y if EXT3_FS=y && EXT3_FS_XATTR
	default y if EXT4_FS=y
	default m if EXT2_FS_XATTR || EXT3_FS_XATTR || EXT4_FS

source "fs/reiserfs/Kconfig"
source "fs/jfs/Kconfig"

source "fs/xfs/Kconfig"
source "fs/gfs2/Kconfig"
source "fs/ocfs2/Kconfig"
source "fs/btrfs/Kconfig"
source "fs/nilfs2/Kconfig"
source "fs/f2fs/Kconfig"

config FS_DAX
	bool "Direct Access (DAX) support"
	depends on MMU
	depends on !(ARM || MIPS || SPARC)
	help
	  Direct Access (DAX) can be used on memory-backed block devices.
	  If the block device supports DAX and the filesystem supports DAX,
	  then you can avoid using the pagecache to buffer I/Os.  Turning
	  on this option will compile in support for DAX; you will need to
	  mount the filesystem using the -o dax option.

	  If you do not have a block device that is capable of using this,
	  or if unsure, say N.  Saying Y will increase the size of the kernel
	  by about 5kB.

endif # BLOCK

# Posix ACL utility routines
#
# Note: Posix ACLs can be implemented without these helpers.  Never use
# this symbol for ifdefs in core code.
#
config FS_POSIX_ACL
	def_bool n

config EXPORTFS
	tristate

config FILE_LOCKING
	bool "Enable POSIX file locking API" if EXPERT
	default y
	help
	  This option enables standard file locking support, required
          for filesystems like NFS and for the flock() system
          call. Disabling this option saves about 11k.

source "fs/notify/Kconfig"

source "fs/quota/Kconfig"

source "fs/autofs4/Kconfig"
source "fs/fuse/Kconfig"
source "fs/overlayfs/Kconfig"

menu "Caches"

source "fs/fscache/Kconfig"
source "fs/cachefiles/Kconfig"

endmenu

if BLOCK
menu "CD-ROM/DVD Filesystems"

source "fs/isofs/Kconfig"
source "fs/udf/Kconfig"

endmenu
endif # BLOCK

if BLOCK
menu "DOS/FAT/NT Filesystems"

source "fs/fat/Kconfig"
source "fs/ntfs/Kconfig"

endmenu
endif # BLOCK

menu "Pseudo filesystems"

source "fs/proc/Kconfig"
source "fs/kernfs/Kconfig"
source "fs/sysfs/Kconfig"

config TMPFS
	bool "Tmpfs virtual memory file system support (former shm fs)"
	depends on SHMEM
	help
	  Tmpfs is a file system which keeps all files in virtual memory.

	  Everything in tmpfs is temporary in the sense that no files will be
	  created on your hard drive. The files live in memory and swap
	  space. If you unmount a tmpfs instance, everything stored therein is
	  lost.

	  See <file:Documentation/filesystems/tmpfs.txt> for details.

config TMPFS_POSIX_ACL
	bool "Tmpfs POSIX Access Control Lists"
	depends on TMPFS
	select TMPFS_XATTR
	select FS_POSIX_ACL
	help
	  POSIX Access Control Lists (ACLs) support additional access rights
	  for users and groups beyond the standard owner/group/world scheme,
	  and this option selects support for ACLs specifically for tmpfs
	  filesystems.

	  If you've selected TMPFS, it's possible that you'll also need
	  this option as there are a number of Linux distros that require
	  POSIX ACL support under /dev for certain features to work properly.
	  For example, some distros need this feature for ALSA-related /dev
	  files for sound to work properly.  In short, if you're not sure,
	  say Y.

	  To learn more about Access Control Lists, visit the POSIX ACLs for
	  Linux website <http://acl.bestbits.at/>.

config TMPFS_XATTR
	bool "Tmpfs extended attributes"
	depends on TMPFS
	default n
	help
	  Extended attributes are name:value pairs associated with inodes by
	  the kernel or by users (see the attr(5) manual page, or visit
	  <http://acl.bestbits.at/> for details).

	  Currently this enables support for the trusted.* and
	  security.* namespaces.

	  You need this for POSIX ACL support on tmpfs.

	  If unsure, say N.

config HUGETLBFS
	bool "HugeTLB file system support"
	depends on X86 || IA64 || SPARC64 || (S390 && 64BIT) || \
		   SYS_SUPPORTS_HUGETLBFS || BROKEN
	help
	  hugetlbfs is a filesystem backing for HugeTLB pages, based on
	  ramfs. For architectures that support it, say Y here and read
	  <file:Documentation/vm/hugetlbpage.txt> for details.

	  If unsure, say N.

config HUGETLB_PAGE
	def_bool HUGETLBFS

source "fs/configfs/Kconfig"
source "fs/efivarfs/Kconfig"

endmenu

menuconfig MISC_FILESYSTEMS
	bool "Miscellaneous filesystems"
	default y
	---help---
	  Say Y here to get to see options for various miscellaneous
	  filesystems, such as filesystems that came from other
	  operating systems.

	  This option alone does not add any kernel code.

	  If you say N, all options in this submenu will be skipped and
	  disabled; if unsure, say Y here.

if MISC_FILESYSTEMS

source "fs/adfs/Kconfig"
source "fs/affs/Kconfig"
source "fs/ecryptfs/Kconfig"
source "fs/hfs/Kconfig"
source "fs/hfsplus/Kconfig"
source "fs/befs/Kconfig"
source "fs/bfs/Kconfig"
source "fs/efs/Kconfig"
source "fs/jffs2/Kconfig"
# UBIFS File system configuration
source "fs/ubifs/Kconfig"
source "fs/logfs/Kconfig"
source "fs/cramfs/Kconfig"
source "fs/squashfs/Kconfig"
source "fs/freevxfs/Kconfig"
source "fs/minix/Kconfig"
source "fs/omfs/Kconfig"
source "fs/hpfs/Kconfig"
source "fs/qnx4/Kconfig"
source "fs/qnx6/Kconfig"
source "fs/romfs/Kconfig"
source "fs/pstore/Kconfig"
source "fs/sysv/Kconfig"
source "fs/ufs/Kconfig"
source "fs/exofs/Kconfig"

endif # MISC_FILESYSTEMS

source "fs/exofs/Kconfig.ore"

menuconfig NETWORK_FILESYSTEMS
	bool "Network File Systems"
	default y
	depends on NET
	---help---
	  Say Y here to get to see options for network filesystems and
	  filesystem-related networking code, such as NFS daemon and
	  RPCSEC security modules.

	  This option alone does not add any kernel code.

	  If you say N, all options in this submenu will be skipped and
	  disabled; if unsure, say Y here.

if NETWORK_FILESYSTEMS

source "fs/nfs/Kconfig"
source "fs/nfsd/Kconfig"

config GRACE_PERIOD
	tristate

config LOCKD
	tristate
	depends on FILE_LOCKING
	select GRACE_PERIOD

config LOCKD_V4
	bool
	depends on NFSD_V3 || NFS_V3
	depends on FILE_LOCKING
	default y

config NFS_ACL_SUPPORT
	tristate
	select FS_POSIX_ACL

config NFS_COMMON
	bool
	depends on NFSD || NFS_FS || LOCKD
	default y

source "net/sunrpc/Kconfig"
source "fs/ceph/Kconfig"
source "fs/cifs/Kconfig"
source "fs/ncpfs/Kconfig"
source "fs/coda/Kconfig"
source "fs/afs/Kconfig"
source "fs/9p/Kconfig"

endif # NETWORK_FILESYSTEMS

source "fs/nls/Kconfig"
source "fs/dlm/Kconfig"

endmenu
/*
 * linux/kernel/time/clocksource.c
 *
 * This file contains the functions which manage clocksource drivers.
 *
 * Copyright (C) 2004, 2005 IBM, John Stultz (johnstul@us.ibm.com)
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 * TODO WishList:
 *   o Allow clocksource drivers to be unregistered
 */

#include <linux/clocksource.h>
#include <linux/sysdev.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/sched.h> /* for spin_unlock_irq() using preempt_count() m68k */
#include <linux/tick.h>
#include <linux/kthread.h>

void timecounter_init(struct timecounter *tc,
		      const struct cyclecounter *cc,
		      u64 start_tstamp)
{
	tc->cc = cc;
	tc->cycle_last = cc->read(cc);
	tc->nsec = start_tstamp;
}
EXPORT_SYMBOL_GPL(timecounter_init);

/**
 * timecounter_read_delta - get nanoseconds since last call of this function
 * @tc:         Pointer to time counter
 *
 * When the underlying cycle counter runs over, this will be handled
 * correctly as long as it does not run over more than once between
 * calls.
 *
 * The first call to this function for a new time counter initializes
 * the time tracking and returns an undefined result.
 */
static u64 timecounter_read_delta(struct timecounter *tc)
{
	cycle_t cycle_now, cycle_delta;
	u64 ns_offset;

	/* read cycle counter: */
	cycle_now = tc->cc->read(tc->cc);

	/* calculate the delta since the last timecounter_read_delta(): */
	cycle_delta = (cycle_now - tc->cycle_last) & tc->cc->mask;

	/* convert to nanoseconds: */
	ns_offset = cyclecounter_cyc2ns(tc->cc, cycle_delta);

	/* update time stamp of timecounter_read_delta() call: */
	tc->cycle_last = cycle_now;

	return ns_offset;
}

u64 timecounter_read(struct timecounter *tc)
{
	u64 nsec;

	/* increment time by nanoseconds since last call */
	nsec = timecounter_read_delta(tc);
	nsec += tc->nsec;
	tc->nsec = nsec;

	return nsec;
}
EXPORT_SYMBOL_GPL(timecounter_read);

u64 timecounter_cyc2time(struct timecounter *tc,
			 cycle_t cycle_tstamp)
{
	u64 cycle_delta = (cycle_tstamp - tc->cycle_last) & tc->cc->mask;
	u64 nsec;

	/*
	 * Instead of always treating cycle_tstamp as more recent
	 * than tc->cycle_last, detect when it is too far in the
	 * future and treat it as old time stamp instead.
	 */
	if (cycle_delta > tc->cc->mask / 2) {
		cycle_delta = (tc->cycle_last - cycle_tstamp) & tc->cc->mask;
		nsec = tc->nsec - cyclecounter_cyc2ns(tc->cc, cycle_delta);
	} else {
		nsec = cyclecounter_cyc2ns(tc->cc, cycle_delta) + tc->nsec;
	}

	return nsec;
}
EXPORT_SYMBOL_GPL(timecounter_cyc2time);

/**
 * clocks_calc_mult_shift - calculate mult/shift factors for scaled math of clocks
 * @mult:	pointer to mult variable
 * @shift:	pointer to shift variable
 * @from:	frequency to convert from
 * @to:		frequency to convert to
 * @minsec:	guaranteed runtime conversion range in seconds
 *
 * The function evaluates the shift/mult pair for the scaled math
 * operations of clocksources and clockevents.
 *
 * @to and @from are frequency values in HZ. For clock sources @to is
 * NSEC_PER_SEC == 1GHz and @from is the counter frequency. For clock
 * event @to is the counter frequency and @from is NSEC_PER_SEC.
 *
 * The @minsec conversion range argument controls the time frame in
 * seconds which must be covered by the runtime conversion with the
 * calculated mult and shift factors. This guarantees that no 64bit
 * overflow happens when the input value of the conversion is
 * multiplied with the calculated mult factor. Larger ranges may
 * reduce the conversion accuracy by chosing smaller mult and shift
 * factors.
 */
void
clocks_calc_mult_shift(u32 *mult, u32 *shift, u32 from, u32 to, u32 minsec)
{
	u64 tmp;
	u32 sft, sftacc= 32;

	/*
	 * Calculate the shift factor which is limiting the conversion
	 * range:
	 */
	tmp = ((u64)minsec * from) >> 32;
	while (tmp) {
		tmp >>=1;
		sftacc--;
	}

	/*
	 * Find the conversion shift/mult pair which has the best
	 * accuracy and fits the maxsec conversion range:
	 */
	for (sft = 32; sft > 0; sft--) {
		tmp = (u64) to << sft;
		do_div(tmp, from);
		if ((tmp >> sftacc) == 0)
			break;
	}
	*mult = tmp;
	*shift = sft;
}

/*[Clocksource internal variables]---------
 * curr_clocksource:
 *	currently selected clocksource.
 * clocksource_list:
 *	linked list with the registered clocksources
 * clocksource_mutex:
 *	protects manipulations to curr_clocksource and the clocksource_list
 * override_name:
 *	Name of the user-specified clocksource.
 */
static struct clocksource *curr_clocksource;
static LIST_HEAD(clocksource_list);
static DEFINE_MUTEX(clocksource_mutex);
static char override_name[32];
static int finished_booting;

#ifdef CONFIG_CLOCKSOURCE_WATCHDOG
static void clocksource_watchdog_work(struct work_struct *work);

static LIST_HEAD(watchdog_list);
static struct clocksource *watchdog;
static struct timer_list watchdog_timer;
static DECLARE_WORK(watchdog_work, clocksource_watchdog_work);
static DEFINE_SPINLOCK(watchdog_lock);
static cycle_t watchdog_last;
static int watchdog_running;

static int clocksource_watchdog_kthread(void *data);
static void __clocksource_change_rating(struct clocksource *cs, int rating);

/*
 * Interval: 0.5sec Threshold: 0.0625s
 */
#define WATCHDOG_INTERVAL (HZ >> 1)
#define WATCHDOG_THRESHOLD (NSEC_PER_SEC >> 4)

static void clocksource_watchdog_work(struct work_struct *work)
{
	/*
	 * If kthread_run fails the next watchdog scan over the
	 * watchdog_list will find the unstable clock again.
	 */
	kthread_run(clocksource_watchdog_kthread, NULL, "kwatchdog");
}

static void __clocksource_unstable(struct clocksource *cs)
{
	cs->flags &= ~(CLOCK_SOURCE_VALID_FOR_HRES | CLOCK_SOURCE_WATCHDOG);
	cs->flags |= CLOCK_SOURCE_UNSTABLE;
	if (finished_booting)
		schedule_work(&watchdog_work);
}

static void clocksource_unstable(struct clocksource *cs, int64_t delta)
{
	printk(KERN_WARNING "Clocksource %s unstable (delta = %Ld ns)\n",
	       cs->name, delta);
	__clocksource_unstable(cs);
}

/**
 * clocksource_mark_unstable - mark clocksource unstable via watchdog
 * @cs:		clocksource to be marked unstable
 *
 * This function is called instead of clocksource_change_rating from
 * cpu hotplug code to avoid a deadlock between the clocksource mutex
 * and the cpu hotplug mutex. It defers the update of the clocksource
 * to the watchdog thread.
 */
void clocksource_mark_unstable(struct clocksource *cs)
{
	unsigned long flags;

	spin_lock_irqsave(&watchdog_lock, flags);
	if (!(cs->flags & CLOCK_SOURCE_UNSTABLE)) {
		if (list_empty(&cs->wd_list))
			list_add(&cs->wd_list, &watchdog_list);
		__clocksource_unstable(cs);
	}
	spin_unlock_irqrestore(&watchdog_lock, flags);