POSIX: add posix_fallocate and a preallocate syscall

the preallocate syscall will call the preallocate filesystem hook, if available.

fix #6285

Change-Id: Ifff4595548610c8e009d4e5ffb64c37e0884e62d
Reviewed-on: https://review.haiku-os.org/c/haiku/+/3382
Reviewed-by: Jérôme Duval <[email protected]>

headers/posix/fcntl.h

@@ -99,6 +99,7 @@ extern int	openat(int fd, const char *path, int openMode, ...);
 extern int	fcntl(int fd, int op, ...);
 
 extern int	posix_fadvise(int fd, off_t offset, off_t len, int advice);
+extern int	posix_fallocate(int fd, off_t offset, off_t len);
 
 #ifdef __cplusplus
 }

headers/private/kernel/vfs.h

@@ -252,6 +252,7 @@ int			_user_dup(int fd);
 int			_user_dup2(int ofd, int nfd);
 status_t	_user_lock_node(int fd);
 status_t	_user_unlock_node(int fd);
+status_t	_user_preallocate(int fd, off_t offset, off_t length);
 
 /* socket user prototypes (implementation in socket.cpp) */
 int			_user_socket(int family, int type, int protocol);

headers/private/system/syscalls.h

@@ -338,6 +338,7 @@ extern status_t		_kern_lock_node(int fd);
 extern status_t		_kern_unlock_node(int fd);
 extern status_t		_kern_get_next_fd_info(team_id team, uint32 *_cookie,
 						struct fd_info *info, size_t infoSize);
+extern status_t		_kern_preallocate(int fd, off_t offset, off_t length);
 
 // socket functions
 extern int			_kern_socket(int family, int type, int protocol);