[patch 4/9] locks: allow ->lock() to return FILE_LOCK_DEFERRED

From: Miklos Szeredi
Date: Fri May 09 2008 - 08:43:20 EST


From: Miklos Szeredi <mszeredi@xxxxxxx>

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 <mszeredi@xxxxxxx>
CC: "J. Bruce Fields" <bfields@xxxxxxxxxxxx>
CC: Matthew Wilcox <matthew@xxxxxx>
---
fs/locks.c | 23 +++++++++--------------
1 file changed, 9 insertions(+), 14 deletions(-)

Index: linux-2.6/fs/locks.c
===================================================================
--- linux-2.6.orig/fs/locks.c 2008-05-09 14:04:47.000000000 +0200
+++ linux-2.6/fs/locks.c 2008-05-09 14:04:48.000000000 +0200
@@ -1753,21 +1753,16 @@ static int do_lock_file_wait(struct file
if (error)
return error;

- if (filp->f_op && filp->f_op->lock != NULL)
- error = filp->f_op->lock(filp, cmd, fl);
- else {
- for (;;) {
- error = posix_lock_file(filp, fl, NULL);
- if (error != FILE_LOCK_DEFERRED)
- break;
- error = wait_event_interruptible(fl->fl_wait,
- !fl->fl_next);
- if (!error)
- continue;
-
- locks_delete_block(fl);
+ for (;;) {
+ error = vfs_lock_file(filp, cmd, fl, NULL);
+ if (error != FILE_LOCK_DEFERRED)
break;
- }
+ error = wait_event_interruptible(fl->fl_wait, !fl->fl_next);
+ if (!error)
+ continue;
+
+ locks_delete_block(fl);
+ break;
}

return error;

--
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