Merge the remaining autofs4 dentry ops tables.  It doesn't matter if
d_automount and d_manage are present on something that's not mountable or
holdable as these ops are only used if the appropriate flags are set in
dentry->d_flags.

[AV] switch to ->s_d_op, since now _everything_ on autofs4 is using the
same dentry_operations.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

There are now two distinct dentry operations uses. One for dentrys
that trigger mounts and one for dentrys that do not.

Rationalize the use of these dentry operations and rename them to
reflect their function.
Signed-off-by: NIan Kent <raven@themaw.net>
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Since the use of ->follow_link() has been eliminated there is no
need to separate the indirect and direct inode operations.
Signed-off-by: NIan Kent <raven@themaw.net>
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Remove code that is not used due to the use of ->d_automount()
and ->d_manage().
Signed-off-by: NIan Kent <raven@themaw.net>
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

This patch required a previous patch to add the ->d_automount()
dentry operation.

Add a function to use the newly defined ->d_manage() dentry operation
for blocking during mount and expire.

Whether the VFS calls the dentry operations d_automount() and d_manage()
is controled by the DMANAGED_AUTOMOUNT and DMANAGED_TRANSIT flags. autofs
uses the d_automount() operation to callback to user space to request
mount operations and the d_manage() operation to block walks into mounts
that are under construction or destruction.

In order to prevent these functions from being called unnecessarily the
DMANAGED_* flags are cleared for cases which would cause this. In the
common case the DMANAGED_AUTOMOUNT and DMANAGED_TRANSIT flags are both
set for dentrys waiting to be mounted. The DMANAGED_TRANSIT flag is
cleared upon successful mount request completion and set during expire
runs, both during the dentry expire check, and if selected for expire,
is left set until a subsequent successful mount request completes.

The exception to this is the so-called rootless multi-mount which has
no actual mount at its base. In this case the DMANAGED_AUTOMOUNT flag
is cleared upon successful mount request completion as well and set
again after a successful expire.
Signed-off-by: NIan Kent <raven@themaw.net>
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Add a function to use the newly defined ->d_automount() dentry operation
for triggering mounts instead of doing the user space callback in ->lookup()
and ->d_revalidate().

Note, to be useful the subsequent patch to add the ->d_manage() dentry
operation is also needed so the discussion of functionality is deferred to
that patch.
Signed-off-by: NIan Kent <raven@themaw.net>
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Add a dentry op (d_manage) to permit a filesystem to hold a process and make it
sleep when it tries to transit away from one of that filesystem's directories
during a pathwalk.  The operation is keyed off a new dentry flag
(DCACHE_MANAGE_TRANSIT).

The filesystem is allowed to be selective about which processes it holds and
which it permits to continue on or prohibits from transiting from each flagged
directory.  This will allow autofs to hold up client processes whilst letting
its userspace daemon through to maintain the directory or the stuff behind it
or mounted upon it.

The ->d_manage() dentry operation:

	int (*d_manage)(struct path *path, bool mounting_here);

takes a pointer to the directory about to be transited away from and a flag
indicating whether the transit is undertaken by do_add_mount() or
do_move_mount() skipping through a pile of filesystems mounted on a mountpoint.

It should return 0 if successful and to let the process continue on its way;
-EISDIR to prohibit the caller from skipping to overmounted filesystems or
automounting, and to use this directory; or some other error code to return to
the user.

->d_manage() is called with namespace_sem writelocked if mounting_here is true
and no other locks held, so it may sleep.  However, if mounting_here is true,
it may not initiate or wait for a mount or unmount upon the parameter
directory, even if the act is actually performed by userspace.

Within fs/namei.c, follow_managed() is extended to check with d_manage() first
on each managed directory, before transiting away from it or attempting to
automount upon it.

follow_down() is renamed follow_down_one() and should only be used where the
filesystem deliberately intends to avoid management steps (e.g. autofs).

A new follow_down() is added that incorporates the loop done by all other
callers of follow_down() (do_add/move_mount(), autofs and NFSD; whilst AFS, NFS
and CIFS do use it, their use is removed by converting them to use
d_automount()).  The new follow_down() calls d_manage() as appropriate.  It
also takes an extra parameter to indicate if it is being called from mount code
(with namespace_sem writelocked) which it passes to d_manage().  follow_down()
ignores automount points so that it can be used to mount on them.

__follow_mount_rcu() is made to abort rcu-walk mode if it hits a directory with
DCACHE_MANAGE_TRANSIT set on the basis that we're probably going to have to
sleep.  It would be possible to enter d_manage() in rcu-walk mode too, and have
that determine whether to abort or not itself.  That would allow the autofs
daemon to continue on in rcu-walk mode.

Note that DCACHE_MANAGE_TRANSIT on a directory should be cleared when it isn't
required as every tranist from that directory will cause d_manage() to be
invoked.  It can always be set again when necessary.

==========================
WHAT THIS MEANS FOR AUTOFS
==========================

Autofs currently uses the lookup() inode op and the d_revalidate() dentry op to
trigger the automounting of indirect mounts, and both of these can be called
with i_mutex held.

autofs knows that the i_mutex will be held by the caller in lookup(), and so
can drop it before invoking the daemon - but this isn't so for d_revalidate(),
since the lock is only held on _some_ of the code paths that call it.  This
means that autofs can't risk dropping i_mutex from its d_revalidate() function
before it calls the daemon.

The bug could manifest itself as, for example, a process that's trying to
validate an automount dentry that gets made to wait because that dentry is
expired and needs cleaning up:

	mkdir         S ffffffff8014e05a     0 32580  24956
	Call Trace:
	 [<ffffffff885371fd>] :autofs4:autofs4_wait+0x674/0x897
	 [<ffffffff80127f7d>] avc_has_perm+0x46/0x58
	 [<ffffffff8009fdcf>] autoremove_wake_function+0x0/0x2e
	 [<ffffffff88537be6>] :autofs4:autofs4_expire_wait+0x41/0x6b
	 [<ffffffff88535cfc>] :autofs4:autofs4_revalidate+0x91/0x149
	 [<ffffffff80036d96>] __lookup_hash+0xa0/0x12f
	 [<ffffffff80057a2f>] lookup_create+0x46/0x80
	 [<ffffffff800e6e31>] sys_mkdirat+0x56/0xe4

versus the automount daemon which wants to remove that dentry, but can't
because the normal process is holding the i_mutex lock:

	automount     D ffffffff8014e05a     0 32581      1              32561
	Call Trace:
	 [<ffffffff80063c3f>] __mutex_lock_slowpath+0x60/0x9b
	 [<ffffffff8000ccf1>] do_path_lookup+0x2ca/0x2f1
	 [<ffffffff80063c89>] .text.lock.mutex+0xf/0x14
	 [<ffffffff800e6d55>] do_rmdir+0x77/0xde
	 [<ffffffff8005d229>] tracesys+0x71/0xe0
	 [<ffffffff8005d28d>] tracesys+0xd5/0xe0

which means that the system is deadlocked.

This patch allows autofs to hold up normal processes whilst the daemon goes
ahead and does things to the dentry tree behind the automouter point without
risking a deadlock as almost no locks are held in d_manage() and none in
d_automount().
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Was-Acked-by: NIan Kent <raven@themaw.net>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

dcache_lock no longer protects anything. remove it.
Signed-off-by: NNick Piggin <npiggin@kernel.dk>

Protect d_subdirs and d_child with d_lock, except in filesystems that aren't
using dcache_lock for these anyway (eg. using i_mutex).

Note: if we change the locking rule in future so that ->d_child protection is
provided only with ->d_parent->d_lock, it may allow us to reduce some locking.
But it would be an exception to an otherwise regular locking scheme, so we'd
have to see some good results. Probably not worthwhile.
Signed-off-by: NNick Piggin <npiggin@kernel.dk>

Protect d_unhashed(dentry) condition with d_lock. This means keeping
DCACHE_UNHASHED bit in synch with hash manipulations.
Signed-off-by: NNick Piggin <npiggin@kernel.dk>

This reverts commit 213614d5.

Alas, ->d_revalidate() can't rely on ->lookup() finishing what
it's started; if d_alloc() in do_lookup() fails, we are not going
to call ->lookup() at all.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

We need to be able to cope with the directory mutex being held during
->d_revalidate() in some cases, but not all cases, and not necessarily by
us.  Because we need to release the mutex when we call back to the daemon
to do perform a mount we must be sure that it is us who holds the mutex so
we must redirect mount requests to ->lookup() if the mutex is held.
Signed-off-by: NIan Kent <raven@themaw.net>
Cc: Sage Weil <sage@newdream.net>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Andreas Dilger <adilger@sun.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Yehuda Saheh <yehuda@newdream.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Eliminate the use of the d_lock spin lock by using the autofs super block
info spin lock.  This reduces the number of spin locks we use by one and
makes the code for the following patch (to redirect ->d_revalidate() to
->lookup()) a little simpler.
Signed-off-by: NIan Kent <raven@themaw.net>
Cc: Sage Weil <sage@newdream.net>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Andreas Dilger <adilger@sun.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Yehuda Saheh <yehuda@newdream.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Define some simple helper functions for adding and deleting entries on the
expiring dentry list.
Signed-off-by: NIan Kent <raven@themaw.net>
Cc: Sage Weil <sage@newdream.net>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Andreas Dilger <adilger@sun.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Yehuda Saheh <yehuda@newdream.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Define some simple helper functions for adding and deleting entries on the
active (and unhashed) dentry list.
Signed-off-by: NIan Kent <raven@themaw.net>
Cc: Sage Weil <sage@newdream.net>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Andreas Dilger <adilger@sun.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Yehuda Saheh <yehuda@newdream.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

A significant portion of the autofs_dev_ioctl_expire() and
autofs4_expire_multi() functions is duplicated code.  This patch cleans that
up.
Signed-off-by: NIan Kent <raven@themaw.net>
Signed-off-by: NJeff Moyer <jmoyer@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

- the type assigned at mount when no type is given is changed
  from 0 to AUTOFS_TYPE_INDIRECT. This was done because 0 and
  AUTOFS_TYPE_INDIRECT were being treated implicitly as the same
  type.

- previously, an offset mount had it's type set to
  AUTOFS_TYPE_DIRECT|AUTOFS_TYPE_OFFSET but the mount control
  re-implementation needs to be able distinguish all three types.
  So this was changed to make the type setting explicit.

- a type AUTOFS_TYPE_ANY was added for use by the re-implementation
  when checking if a given path is a mountpoint. It's not really a
  type as we use this to ask if a given path is a mountpoint in the
  autofs_dev_ioctl_ismountpoint() function.

- functions to set and test the autofs mount types have been added to
  improve readability and make the type usage explicit.

- the mount type is used from user space for the mount control
  re-implementtion so, for consistency, all the definitions have
  been moved to the user space include file include/linux/auto_fs4.h.
Signed-off-by: NIan Kent <raven@themaw.net>
Signed-off-by: NJeff Moyer <jmoyer@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Add a miscellaneous device to the autofs4 module for routing ioctls.  This
provides the ability to obtain an ioctl file handle for an autofs mount
point that is possibly covered by another mount.

The actual problem with autofs is that it can't reconnect to existing
mounts.  Immediately one things of just adding the ability to remount
autofs file systems would solve it, but alas, that can't work.  This is
because autofs direct mounts and the implementation of "on demand mount
and expire" of nested mount trees have the file system mounted on top of
the mount trigger dentry.

To resolve this a miscellaneous device node for routing ioctl commands to
these mount points has been implemented in the autofs4 kernel module and a
library added to autofs.  This provides the ability to open a file
descriptor for these over mounted autofs mount points.

Please refer to Documentation/filesystems/autofs4-mount-control.txt for a
discussion of the problem, implementation alternatives considered and a
description of the interface.

[akpm@linux-foundation.org: coding-style fixes]
[akpm@linux-foundation.org: build fix]
Signed-off-by: NIan Kent <raven@themaw.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Track the uid and gid of the last process to request a mount for on an
autofs dentry.

[akpm@linux-foundation.org: fix tpyo in comment]
Signed-off-by: NIan Kent <raven@themaw.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Usage of the AUTOFS_TYPE_* defines is a little confusing and appears
inconsistent.
Signed-off-by: NIan Kent <raven@themaw.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patch re-orgnirzes the checking for and waiting on active expires and
elininates redundant checks.
Signed-off-by: NIan Kent <raven@themaw.net>
Cc: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

For direct and offset type mounts that are covered by another mount we
cannot check the AUTOFS_INF_EXPIRING flag during a path walk which leads
to lookups walking into an expiring mount while it is being expired.

For example, for the direct multi-mount map entry with a couple of
offsets:

/race/mm1  /      <server1>:/<path1>
           /om1   <server2>:/<path2>
           /om2   <server1>:/<path3>

an autofs trigger mount is mounted on /race/mm1 and when accessed it is
over mounted and trigger mounts made for /race/mm1/om1 and /race/mm1/om2.
So it isn't possible for path walks to see the expiring flag at all and
they happily walk into the file system while it is expiring.

When expiring these mounts follow_down() must stop at the autofs mount and
all processes must block in the ->follow_link() method (except the daemon)
until the expire is complete.  This is done by decrementing the d_mounted
field of the autofs trigger mount root dentry until the expire is
completed.  In ->follow_link() all processes wait on the expire and the
mount following is completed for the daemon until the expire is complete.
Signed-off-by: NIan Kent <raven@themaw.net>
Cc: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The selection of a dentry for expiration and the setting of the
AUTOFS_INF_EXPIRING flag isn't done atomically which can lead to lookups
walking into an expiring mount.

What happens is that an expire is initiated by the daemon and a dentry is
selected for expire but, since there is no lock held between the selection
and setting of the expiring flag, a process may find the flag clear and
continue walking into the mount tree at the same time the daemon attempts
the expire it.
Signed-off-by: NIan Kent <raven@themaw.net>
Reviewed-by: NJeff Moyer <jmoyer@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

If an autofs mount becomes catatonic before autofs4_wait_release() is
called the wait queue counter will not be decremented down to zero and the
entry will never be freed.  There are also races decrementing the wait
counter in the wait release function.  To deal with this the counter needs
to be updated while holding the wait queue mutex and waiters need to be
woken up unconditionally when the wait is removed from the queue to ensure
we eventually free the wait.
Signed-off-by: NIan Kent <raven@themaw.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The autofs_wait_queue already contains all of the fields of the
struct qstr, so change it into a qstr.

This patch, from Jeff Moyer, has been modified a liitle by myself.
Signed-off-by: NJeff Moyer <jmoyer@redhat.com>
Signed-off-by: NIan Kent <raven@themaw.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

A while ago a patch to resolve a deadlock during directory creation was
merged.  This delayed the hashing of lookup dentrys until the ->mkdir()
(or ->symlink()) operation completed to ensure we always went through
->lookup() instead of also having processes go through ->revalidate() so
our VFS locking remained consistent.

Now we are seeing a couple of side affects of that change in situations
with heavy mount activity.

Two cases have been identified:

1) When a mount request is triggered, due to the delayed hashing, the
   directory created by user space for the mount point doesn't have the
   DCACHE_AUTOFS_PENDING flag set.  In the case of an autofs multi-mount
   where a tree of mount point directories are created this can lead to
   the path walk continuing rather than the dentry being sent to the wait
   queue to wait for request completion.  This is because, if the pending
   flag isn't set, the criteria for deciding this is a mount in progress
   fails to hold, namely that the dentry is not a mount point and has no
   subdirectories.

2) A mount request dentry is initially created negative and unhashed.
   It remains this way until the ->mkdir() callback completes.  Since it
   is unhashed a fresh dentry is used when the user space mount request
   creates the mount point directory.  This leaves the original dentry
   negative and unhashed.  But revalidate has no way to tell the VFS that
   the dentry has changed, other than to force another ->lookup() by
   returning false, which is at best wastefull and at worst not possible.
   This results in an -ENOENT return from the original path walk when in
   fact the mount succeeded.

To resolve this we need to ensure that the same dentry is used in all
calls to ->lookup() during the course of a mount request.  This patch
achieves that by adding the initial dentry to a look aside list and
removes it at ->mkdir() or ->symlink() completion (or when the dentry is
released), since these are the only create operations autofs4 supports.
Signed-off-by: NIan Kent <raven@themaw.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Correct the error of making a positive dentry negative after it has been
instantiated.

The code that makes this error attempts to re-use the dentry from a
concurrent expire and mount to resolve a race and the dentry used for the
lookup must be negative for mounts to trigger in the required cases.  The
fact is that the dentry doesn't need to be re-used because all that is
needed is to preserve the flag that indicates an expire is still
incomplete at the time of the mount request.

This change uses the the dentry to check the flag and wait for the expire
to complete then discards it instead of attempting to re-use it.
Signed-off-by: NIan Kent <raven@themaw.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

__FUNCTION__ is gcc-specific, use __func__
Signed-off-by: NHarvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The set of functions process_session, task_session, process_group and
task_pgrp is confusing, as the names can be mixed with each other when looking
at the code for a long time.

The proposals are to
* equip the functions that return the integer with _nr suffix to
  represent that fact,
* and to make all functions work with task (not process) by making
  the common prefix of the same name.

For monotony the routines signal_session() and set_signal_session() are
replaced with task_session_nr() and set_task_session(), especially since they
are only used with the explicit task->signal dereference.
Signed-off-by: NPavel Emelianov <xemul@openvz.org>
Acked-by: NSerge E. Hallyn <serue@us.ibm.com>
Cc: Kirill Korotaev <dev@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Cedric Le Goater <clg@fr.ibm.com>
Cc: Herbert Poetzl <herbert@13thfloor.at>
Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Jeff Moyer has identified a race between mount and expire.

What happens is that during an expire the situation can arise that a directory
is removed and another lookup is done before the expire issues a completion
status to the kernel module.  In this case, since the the lookup gets a new
dentry, it doesn't know that there is an expire in progress and when it posts
its mount request, matches the existing expire request and waits for its
completion.  ENOENT is then returned to user space from lookup (as the dentry
passed in is now unhashed) without having performed the mount request.

The solution used here is to keep track of dentrys in this unhashed state and
reuse them, if possible, in order to preserve the flags.  Additionally, this
infrastructure will provide the framework for the reintroduction of caching of
mount fails removed earlier in development.
Signed-off-by: NIan Kent <raven@themaw.net>
Acked-by: NJeff Moyer <jmoyer@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Many struct inode_operations in the kernel can be "const".  Marking them const
moves these to the .rodata section, which avoids false sharing with potential
dirty data.  In addition it'll catch accidental writes at compile time to
these shared resources.
Signed-off-by: NArjan van de Ven <arjan@linux.intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Change all the uses of f_{dentry,vfsmnt} to f_path.{dentry,mnt} in the autofs4
filesystem.
Signed-off-by: NJosef "Jeff" Sipek <jsipek@cs.sunysb.edu>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Make sure all dentries refs are released before calling kill_anon_super() so
that the assumption that generic_shutdown_super() can completely destroy the
dentry tree for there will be no external references holds true.

What was being done in the put_super() superblock op, is now done in the
kill_sb() filesystem op instead, prior to calling kill_anon_super().

This makes the struct autofs_sb_info::root member variable redundant (since
sb->s_root is still available), and so that is removed.  The calls to
shrink_dcache_sb() are also removed since they're also redundant as
shrink_dcache_for_umount() will now be called after the cleanup routine.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Acked-by: NIan Kent <raven@themaw.net>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Signed-off-by: NJeff Garzik <jeff@garzik.org>

This patch fixes two problems.

First, the comparison of entries in the waitq.c was incorrect.

Second, the NFY_NONE check was incorrect. The test of whether the dentry
is mounted if ineffective, for example, if an expire fails then we could
wait forever on a non existant expire. The bug was identified by Jeff
Moyer.

The patch changes autofs4 to wait on expires only as this is all that's
needed.  If there is no existing wait when autofs4_wait is call with a type
of NFY_NONE it delays until either a wait appears or the the expire flag is
cleared.
Signed-off-by: NIan Kent <raven@themaw.net>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This is a conversion to make the various file_operations structs in fs/
const.  Basically a regexp job, with a few manual fixups

The goal is both to increase correctness (harder to accidentally write to
shared datastructures) and reducing the false sharing of cachelines with
things that get dirty in .data (while .rodata is nicely read only and thus
cache clean)
Signed-off-by: NArjan van de Ven <arjan@infradead.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Add a proper prototype for autofs4_dentry_release() to autofs_i.h.
Signed-off-by: NAdrian Bunk <bunk@stusta.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Fix accidental underflow of the atomic counter.
Signed-off-by: NIan Kent <raven@themaw.net>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Signed-off-by: NIan Kent <raven@themaw.net>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>