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Commit 6ff958ed authored by Miklos Szeredi's avatar Miklos Szeredi Committed by Linus Torvalds
Browse files

fuse: add atomic open+truncate support 



This patch allows fuse filesystems to implement open(..., O_TRUNC) as a single
request, instead of separate truncate and open requests.

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 17637cba

fs/fuse/dir.c

+3 −0
Original line number Diff line number Diff line
@@ -1083,6 +1083,9 @@ static int fuse_do_setattr(struct dentry *entry, struct iattr *attr, 
			return err;

	}



	if ((attr->ia_valid & ATTR_OPEN) && fc->atomic_o_trunc)

		return 0;



	if (attr->ia_valid & ATTR_SIZE) {

		unsigned long limit;

		if (IS_SWAPFILE(inode))

fs/fuse/file.c

+3 −1
Original line number Diff line number Diff line
@@ -28,7 +28,9 @@ static int fuse_send_open(struct inode *inode, struct file *file, int isdir, 
		return PTR_ERR(req);



	memset(&inarg, 0, sizeof(inarg));

	inarg.flags = file->f_flags & ~(O_CREAT | O_EXCL | O_NOCTTY | O_TRUNC);

	inarg.flags = file->f_flags & ~(O_CREAT | O_EXCL | O_NOCTTY);

	if (!fc->atomic_o_trunc)

		inarg.flags &= ~O_TRUNC;

	req->in.h.opcode = isdir ? FUSE_OPENDIR : FUSE_OPEN;

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

	req->in.numargs = 1;

fs/fuse/fuse_i.h

+3 −0
Original line number Diff line number Diff line
@@ -320,6 +320,9 @@ struct fuse_conn { 
	/** Do readpages asynchronously?  Only set in INIT */

	unsigned async_read : 1;



	/** Do not send separate SETATTR request before open(O_TRUNC)  */

	unsigned atomic_o_trunc : 1;



	/*

	 * The following bitfields are only for optimization purposes

	 * and hence races in setting them will not cause malfunction

fs/fuse/inode.c

+4 −1
Original line number Diff line number Diff line
@@ -531,6 +531,8 @@ static void process_init_reply(struct fuse_conn *fc, struct fuse_req *req) 
				fc->async_read = 1;

			if (!(arg->flags & FUSE_POSIX_LOCKS))

				fc->no_lock = 1;

			if (arg->flags & FUSE_ATOMIC_O_TRUNC)

				fc->atomic_o_trunc = 1;

		} else {

			ra_pages = fc->max_read / PAGE_CACHE_SIZE;

			fc->no_lock = 1;
@@ -553,7 +555,8 @@ static void fuse_send_init(struct fuse_conn *fc, struct fuse_req *req) 
	arg->major = FUSE_KERNEL_VERSION;

	arg->minor = FUSE_KERNEL_MINOR_VERSION;

	arg->max_readahead = fc->bdi.ra_pages * PAGE_CACHE_SIZE;

	arg->flags |= FUSE_ASYNC_READ | FUSE_POSIX_LOCKS | FUSE_FILE_OPS;

	arg->flags |= FUSE_ASYNC_READ | FUSE_POSIX_LOCKS | FUSE_FILE_OPS |

		FUSE_ATOMIC_O_TRUNC;

	req->in.h.opcode = FUSE_INIT;

	req->in.numargs = 1;

	req->in.args[0].size = sizeof(*arg);

include/linux/fuse.h

+1 −0
Original line number Diff line number Diff line
@@ -101,6 +101,7 @@ struct fuse_file_lock { 
#define FUSE_ASYNC_READ		(1 << 0)

#define FUSE_POSIX_LOCKS	(1 << 1)

#define FUSE_FILE_OPS		(1 << 2)

#define FUSE_ATOMIC_O_TRUNC	(1 << 3)



/**

 * Release flags