locks: add special return value for asynchronous locks
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 <mszeredi@suse.cz>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Cc: Matthew Wilcox <matthew@wil.cx>
Cc: David Teigland <teigland@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/lockd/svclock.c b/fs/lockd/svclock.c
index 821b9ac..cf0d5c2 100644
--- a/fs/lockd/svclock.c
+++ b/fs/lockd/svclock.c
@@ -418,8 +418,8 @@
goto out;
case -EAGAIN:
ret = nlm_lck_denied;
- break;
- case -EINPROGRESS:
+ goto out;
+ case FILE_LOCK_DEFERRED:
if (wait)
break;
/* Filesystem lock operation is in progress
@@ -434,10 +434,6 @@
goto out;
}
- ret = nlm_lck_denied;
- if (!wait)
- goto out;
-
ret = nlm_lck_blocked;
/* Append to list of blocked */
@@ -507,7 +503,7 @@
}
error = vfs_test_lock(file->f_file, &lock->fl);
- if (error == -EINPROGRESS) {
+ if (error == FILE_LOCK_DEFERRED) {
ret = nlmsvc_defer_lock_rqst(rqstp, block);
goto out;
}
@@ -731,8 +727,7 @@
switch (error) {
case 0:
break;
- case -EAGAIN:
- case -EINPROGRESS:
+ case FILE_LOCK_DEFERRED:
dprintk("lockd: lock still blocked error %d\n", error);
nlmsvc_insert_block(block, NLM_NEVER);
nlmsvc_release_block(block);