This patch adds a note to enable EXPORT_OP_ASYNC_LOCK for asynchronous lock request handling. Reviewed-by: Jeff Layton <jlayton@xxxxxxxxxx> Signed-off-by: Alexander Aring <aahringo@xxxxxxxxxx> --- fs/locks.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) diff --git a/fs/locks.c b/fs/locks.c index 76ad05f8070a..d4e49a990a8d 100644 --- a/fs/locks.c +++ b/fs/locks.c @@ -2264,11 +2264,13 @@ int fcntl_getlk(struct file *filp, unsigned int cmd, struct flock *flock) * To avoid blocking kernel daemons, such as lockd, that need to acquire POSIX * locks, the ->lock() interface may return asynchronously, before the lock has * been granted or denied by the underlying filesystem, if (and only if) - * lm_grant is set. Callers expecting ->lock() to return asynchronously - * will only use F_SETLK, not F_SETLKW; they will set FL_SLEEP if (and only if) - * the request is for a blocking lock. When ->lock() does return asynchronously, - * it must return FILE_LOCK_DEFERRED, and call ->lm_grant() when the lock - * request completes. + * lm_grant is set. Additionally EXPORT_OP_ASYNC_LOCK in export_operations + * flags need to be set. + * + * Callers expecting ->lock() to return asynchronously will only use F_SETLK, + * not F_SETLKW; they will set FL_SLEEP if (and only if) the request is for a + * blocking lock. When ->lock() does return asynchronously, it must return + * FILE_LOCK_DEFERRED, and call ->lm_grant() when the lock request completes. * If the request is for non-blocking lock the file system should return * FILE_LOCK_DEFERRED then try to get the lock and call the callback routine * with the result. If the request timed out the callback routine will return a -- 2.31.1
