Commit b2b1ff3d authored by Trond Myklebust's avatar Trond Myklebust
Browse files

NFS: Allow optimisation of lseek(fd, SEEK_CUR, 0) on directories 



There should be no need to grab the inode lock if we're only reading
the file offset.

Signed-off-by: default avatarTrond Myklebust <trond.myklebust@hammerspace.com>
parent 411ae722

fs/nfs/dir.c

+16 −10
Original line number Diff line number Diff line
@@ -904,23 +904,29 @@ static loff_t nfs_llseek_dir(struct file *filp, loff_t offset, int whence) 
	dfprintk(FILE, "NFS: llseek dir(%pD2, %lld, %d)\n",

			filp, offset, whence);



	inode_lock(inode);

	switch (whence) {

		case 1:

			offset += filp->f_pos;

		case 0:

			if (offset >= 0)

				break;

	default:

			offset = -EINVAL;

			goto out;

		return -EINVAL;

	case SEEK_SET:

		if (offset < 0)

			return -EINVAL;

		inode_lock(inode);

		break;

	case SEEK_CUR:

		if (offset == 0)

			return filp->f_pos;

		inode_lock(inode);

		offset += filp->f_pos;

		if (offset < 0) {

			inode_unlock(inode);

			return -EINVAL;

		}

	}

	if (offset != filp->f_pos) {

		filp->f_pos = offset;

		dir_ctx->dir_cookie = 0;

		dir_ctx->duped = 0;

	}

out:

	inode_unlock(inode);

	return offset;

}