Commit b500531e authored by Oleg Drokin's avatar Oleg Drokin Committed by Linus Torvalds
Browse files

[PATCH] Introduce FMODE_EXEC file flag 



Introduce FMODE_EXEC file flag, to indicate that file is being opened for
execution.  This is useful for distributed filesystems to maintain
consistent behavior for returning ETXTBUSY when opening for write and
execution happens on different nodes.

akpm:

  Needed by Lustre at present.  I assume their objective to to work towards
  being able to install Lustre on an unmodified distro kernel, which seems
  sane.  It should have zero runtime cost.

  Trond and Chuck indicate that NFS4 can probably use this too, for the same
  thing.

  Steven says it's also on the GFS todo list.

Signed-off-by: default avatarOleg Drokin <green@linuxhacker.ru>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: Chuck Lever <cel@citi.umich.edu>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 619d5d8a

fs/exec.c

+2 −2
Original line number Diff line number Diff line
@@ -127,7 +127,7 @@ asmlinkage long sys_uselib(const char __user * library) 
	struct nameidata nd;

	int error;



	error = __user_path_lookup_open(library, LOOKUP_FOLLOW, &nd, FMODE_READ);

	error = __user_path_lookup_open(library, LOOKUP_FOLLOW, &nd, FMODE_READ|FMODE_EXEC);

	if (error)

		goto out;
@@ -477,7 +477,7 @@ struct file *open_exec(const char *name) 
	int err;

	struct file *file;



	err = path_lookup_open(AT_FDCWD, name, LOOKUP_FOLLOW, &nd, FMODE_READ);

	err = path_lookup_open(AT_FDCWD, name, LOOKUP_FOLLOW, &nd, FMODE_READ|FMODE_EXEC);

	file = ERR_PTR(err);



	if (!err) {

include/linux/fs.h

+5 −0
Original line number Diff line number Diff line
@@ -65,6 +65,11 @@ extern int dir_notify_enable; 
#define FMODE_PREAD	8

#define FMODE_PWRITE	FMODE_PREAD	/* These go hand in hand */



/* File is being opened for execution. Primary users of this flag are

   distributed filesystems that can use it to achieve correct ETXTBUSY

   behavior for cross-node execution/opening_for_writing of files */

#define FMODE_EXEC	16



#define RW_MASK		1

#define RWA_MASK	2

#define READ 0