Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit a9ff4f87 authored by Miklos Szeredi's avatar Miklos Szeredi Committed by Linus Torvalds
Browse files

fuse: support BSD locking semantics 



It is trivial to add support for flock(2) semantics to the existing protocol,
by setting the lock owner field to the file pointer, and passing a new
FUSE_LK_FLOCK flag with the locking request.

Signed-off-by: default avatarMiklos Szeredi <mszeredi@suse.cz>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 6ff958ed

fs/fuse/file.c

+27 −5
Original line number Diff line number Diff line
@@ -699,7 +699,8 @@ static int convert_fuse_file_lock(const struct fuse_file_lock *ffl, 
}



static void fuse_lk_fill(struct fuse_req *req, struct file *file,

			 const struct file_lock *fl, int opcode, pid_t pid)

			 const struct file_lock *fl, int opcode, pid_t pid,

			 int flock)

{

	struct inode *inode = file->f_path.dentry->d_inode;

	struct fuse_conn *fc = get_fuse_conn(inode);
@@ -712,6 +713,8 @@ static void fuse_lk_fill(struct fuse_req *req, struct file *file, 
	arg->lk.end = fl->fl_end;

	arg->lk.type = fl->fl_type;

	arg->lk.pid = pid;

	if (flock)

		arg->lk_flags |= FUSE_LK_FLOCK;

	req->in.h.opcode = opcode;

	req->in.h.nodeid = get_node_id(inode);

	req->in.numargs = 1;
@@ -731,7 +734,7 @@ static int fuse_getlk(struct file *file, struct file_lock *fl) 
	if (IS_ERR(req))

		return PTR_ERR(req);



	fuse_lk_fill(req, file, fl, FUSE_GETLK, 0);

	fuse_lk_fill(req, file, fl, FUSE_GETLK, 0, 0);

	req->out.numargs = 1;

	req->out.args[0].size = sizeof(outarg);

	req->out.args[0].value = &outarg;
@@ -744,7 +747,7 @@ static int fuse_getlk(struct file *file, struct file_lock *fl) 
	return err;

}



static int fuse_setlk(struct file *file, struct file_lock *fl)

static int fuse_setlk(struct file *file, struct file_lock *fl, int flock)

{

	struct inode *inode = file->f_path.dentry->d_inode;

	struct fuse_conn *fc = get_fuse_conn(inode);
@@ -761,7 +764,7 @@ static int fuse_setlk(struct file *file, struct file_lock *fl) 
	if (IS_ERR(req))

		return PTR_ERR(req);



	fuse_lk_fill(req, file, fl, opcode, pid);

	fuse_lk_fill(req, file, fl, opcode, pid, flock);

	request_send(fc, req);

	err = req->out.h.error;

	/* locking is restartable */
@@ -787,11 +790,28 @@ static int fuse_file_lock(struct file *file, int cmd, struct file_lock *fl) 
		if (fc->no_lock)

			err = posix_lock_file_wait(file, fl);

		else

			err = fuse_setlk(file, fl);

			err = fuse_setlk(file, fl, 0);

	}

	return err;

}



static int fuse_file_flock(struct file *file, int cmd, struct file_lock *fl)

{

	struct inode *inode = file->f_path.dentry->d_inode;

	struct fuse_conn *fc = get_fuse_conn(inode);

	int err;



	if (fc->no_lock) {

		err = flock_lock_file_wait(file, fl);

	} else {

		/* emulate flock with POSIX locks */

		fl->fl_owner = (fl_owner_t) file;

		err = fuse_setlk(file, fl, 1);

	}



	return err;

}



static sector_t fuse_bmap(struct address_space *mapping, sector_t block)

{

	struct inode *inode = mapping->host;
@@ -840,6 +860,7 @@ static const struct file_operations fuse_file_operations = { 
	.release	= fuse_release,

	.fsync		= fuse_fsync,

	.lock		= fuse_file_lock,

	.flock		= fuse_file_flock,

	.splice_read	= generic_file_splice_read,

};
@@ -852,6 +873,7 @@ static const struct file_operations fuse_direct_io_file_operations = { 
	.release	= fuse_release,

	.fsync		= fuse_fsync,

	.lock		= fuse_file_lock,

	.flock		= fuse_file_flock,

	/* no mmap and splice_read */

};

include/linux/fuse.h

+8 −0
Original line number Diff line number Diff line
@@ -13,6 +13,7 @@ 
 *

 * 7.9:

 *  - new fuse_getattr_in input argument of GETATTR

 *  - add lk_flags in fuse_lk_in

 */



#include <asm/types.h>
@@ -113,6 +114,11 @@ struct fuse_file_lock { 
 */

#define FUSE_GETATTR_FH		(1 << 0)



/**

 * Lock flags

 */

#define FUSE_LK_FLOCK		(1 << 0)



enum fuse_opcode {

	FUSE_LOOKUP	   = 1,

	FUSE_FORGET	   = 2,  /* no reply */
@@ -295,6 +301,8 @@ struct fuse_lk_in { 
	__u64	fh;

	__u64	owner;

	struct fuse_file_lock lk;

	__u32	lk_flags;

	__u32	padding;

};



struct fuse_lk_out {