[PATCH] Introduce FMODE_EXEC file flag (b500531e) · Commits · 戴 / test

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:

Oleg 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:

Andrew Morton <akpm@osdl.org> Signed-off-by:

Linus Torvalds <torvalds@osdl.org>

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

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