linux.git/fs/locks.c, branch v2.6.27

SL*B: drop kmem cache argument from constructor

2008-07-26T19:00:07+00:00

Kmem cache passed to constructor is only needed for constructors that are
themselves multiplexeres.  Nobody uses this "feature", nor does anybody uses
passed kmem cache in non-trivial way, so pass only pointer to object.

Non-trivial places are:
	arch/powerpc/mm/init_64.c
	arch/powerpc/mm/hugetlbpage.c

This is flag day, yes.

Signed-off-by: Alexey Dobriyan 
Acked-by: Pekka Enberg 
Acked-by: Christoph Lameter 
Cc: Jon Tollefson 
Cc: Nick Piggin 
Cc: Matt Mackall 
[akpm@linux-foundation.org: fix arch/powerpc/mm/hugetlbpage.c]
[akpm@linux-foundation.org: fix mm/slab.c]
[akpm@linux-foundation.org: fix ubifs]
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

locks: allow ->lock() to return FILE_LOCK_DEFERRED

2008-07-25T17:53:48+00:00

Allow filesystem's ->lock() method to call posix_lock_file() instead of
posix_lock_file_wait(), and return FILE_LOCK_DEFERRED.  This makes it
possible to implement a such a ->lock() function, that works with the lock
manager, which needs the call to be asynchronous.

Now the vfs_lock_file() helper can be used, so this is a cleanup as well.

Signed-off-by: Miklos Szeredi 
Cc: "J. Bruce Fields" 
Cc: Trond Myklebust 
Cc: Matthew Wilcox 
Cc: David Teigland 
Cc: Christoph Hellwig 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

locks: cleanup code duplication

2008-07-25T17:53:48+00:00

Extract common code into a function.

Signed-off-by: Miklos Szeredi 
Cc: "J. Bruce Fields" 
Cc: Trond Myklebust 
Cc: Matthew Wilcox 
Cc: David Teigland 
Cc: Christoph Hellwig 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

locks: add special return value for asynchronous locks

2008-07-25T17:53:47+00:00

Use a special error value FILE_LOCK_DEFERRED to mean that a locking
operation returned asynchronously.  This is returned by

  posix_lock_file() for sleeping locks to mean that the lock has been
  queued on the block list, and will be woken up when it might become
  available and needs to be retried (either fl_lmops->fl_notify() is
  called or fl_wait is woken up).

  f_op->lock() to mean either the above, or that the filesystem will
  call back with fl_lmops->fl_grant() when the result of the locking
  operation is known.  The filesystem can do this for sleeping as well
  as non-sleeping locks.

This is to make sure, that return values of -EAGAIN and -EINPROGRESS by
filesystems are not mistaken to mean an asynchronous locking.

This also makes error handling in fs/locks.c and lockd/svclock.c slightly
cleaner.

Signed-off-by: Miklos Szeredi 
Cc: Trond Myklebust 
Cc: "J. Bruce Fields" 
Cc: Matthew Wilcox 
Cc: David Teigland 
Cc: Christoph Hellwig 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[patch 4/4] flock: remove unused fields from file_lock_operations

2008-06-23T15:52:30+00:00

fl_insert and fl_remove are not used right now in the kernel. Remove them.

Signed-off-by: Denis V. Lunev 
Cc: Matthew Wilcox 
Cc: Alexander Viro 
Cc: "J. Bruce Fields" 
Signed-off-by: Andrew Morton 
Signed-off-by: Al Viro

Add new 'cond_resched_bkl()' helper function

2008-05-11T23:04:48+00:00

It acts exactly like a regular 'cond_resched()', but will not get
optimized away when CONFIG_PREEMPT is set.

Normal kernel code is already preemptable in the presense of
CONFIG_PREEMPT, so cond_resched() is optimized away (see commit
02b67cc3ba36bdba351d6c3a00593f4ec550d9d3 "sched: do not do
cond_resched() when CONFIG_PREEMPT").

But when wanting to conditionally reschedule while holding a lock, you
need to use "cond_sched_lock(lock)", and the new function is the BKL
equivalent of that.

Also make fs/locks.c use it.

Signed-off-by: Linus Torvalds

[PATCH] fix SMP ordering hole in fcntl_setlk()

2008-05-06T17:58:34+00:00

fcntl_setlk()/close() race prevention has a subtle hole - we need to
make sure that if we *do* have an fcntl/close race on SMP box, the
access to descriptor table and inode->i_flock won't get reordered.

As it is, we get STORE inode->i_flock, LOAD descriptor table entry vs.
STORE descriptor table entry, LOAD inode->i_flock with not a single
lock in common on both sides.  We do have BKL around the first STORE,
but check in locks_remove_posix() is outside of BKL and for a good
reason - we don't want BKL on common path of close(2).

Solution is to hold ->file_lock around fcheck() in there; that orders
us wrt removal from descriptor table that preceded locks_remove_posix()
on close path and we either come first (in which case eviction will be
handled by the close side) or we'll see the effect of close and do
eviction ourselves.  Note that even though it's read-only access,
we do need ->file_lock here - rcu_read_lock() won't be enough to
order the things.

Signed-off-by: Al Viro

[PATCH] split linux/file.h

2008-05-01T17:08:16+00:00

Initial splitoff of the low-level stuff; taken to fdtable.h

Signed-off-by: Al Viro

Export __locks_copy_lock() so modular lockd builds

2008-04-25T22:49:46+00:00

Commit 1a747ee0 ("locks: don't call ->copy_lock methods on return of
conflicting locks") changed fs/lockd/svclock.c to call
__locks_copy_lock() instead of locks_copy_lock(), but lockd can be built
as a module and __locks_copy_lock() is not exported, which causes a
build error

    ERROR: "__locks_copy_lock" [fs/lockd/lockd.ko] undefined!

with CONFIG_LOCKD=m.

Fix this by exporting __locks_copy_lock().

Signed-off-by: Roland Dreier 
Signed-off-by: Linus Torvalds

locks: don't call ->copy_lock methods on return of conflicting locks

2008-04-25T17:00:11+00:00

The file_lock structure is used both as a heavy-weight representation of
an active lock, with pointers to reference-counted structures, etc., and
as a simple container for parameters that describe a file lock.

The conflicting lock returned from __posix_lock_file is an example of
the latter; so don't call the filesystem or lock manager callbacks when
copying to it.  This also saves the need for an unnecessary
locks_init_lock in the nfsv4 server.

Thanks to Trond for pointing out the error.

Signed-off-by: J. Bruce Fields 
Cc: Trond Myklebust