Initial Spring 2016 commit.
This commit is contained in:
Geoffrey Challen
316
kern/include/vnode.h
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316
kern/include/vnode.h
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/*
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* Copyright (c) 2000, 2001, 2002, 2003, 2004, 2005, 2008, 2009
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* The President and Fellows of Harvard College.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE UNIVERSITY AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE UNIVERSITY OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#ifndef _VNODE_H_
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#define _VNODE_H_
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#include <spinlock.h>
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struct uio;
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struct stat;
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/*
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* A struct vnode is an abstract representation of a file.
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*
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* It is an interface in the Java sense that allows the kernel's
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* filesystem-independent code to interact usefully with multiple sets
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* of filesystem code.
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*/
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/*
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* Abstract low-level file.
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*
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* Note: vn_fs may be null if the vnode refers to a device.
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*/
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struct vnode {
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int vn_refcount; /* Reference count */
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struct spinlock vn_countlock; /* Lock for vn_refcount */
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struct fs *vn_fs; /* Filesystem vnode belongs to */
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void *vn_data; /* Filesystem-specific data */
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const struct vnode_ops *vn_ops; /* Functions on this vnode */
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};
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/*
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* Abstract operations on a vnode.
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*
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* These are used in the form VOP_FOO(vnode, args), which are macros
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* that expands to vnode->vn_ops->vop_foo(vnode, args). The operations
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* "foo" are:
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*
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* vop_eachopen - Called on *each* open() of a file. Can be used to
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* reject illegal or undesired open modes. Note that
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* various operations can be performed without the
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* file actually being opened.
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* The vnode need not look at O_CREAT, O_EXCL, or
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* O_TRUNC, as these are handled in the VFS layer.
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*
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* VOP_EACHOPEN should not be called directly from
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* above the VFS layer - use vfs_open() to open vnodes.
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*
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* vop_reclaim - Called when vnode is no longer in use.
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*
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*****************************************
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*
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* vop_read - Read data from file to uio, at offset specified
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* in the uio, updating uio_resid to reflect the
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* amount read, and updating uio_offset to match.
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* Not allowed on directories or symlinks.
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*
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* vop_readlink - Read the contents of a symlink into a uio.
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* Not allowed on other types of object.
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*
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* vop_getdirentry - Read a single filename from a directory into a
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* uio, choosing what name based on the offset
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* field in the uio, and updating that field.
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* Unlike with I/O on regular files, the value of
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* the offset field is not interpreted outside
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* the filesystem and thus need not be a byte
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* count. However, the uio_resid field should be
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* handled in the normal fashion.
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* On non-directory objects, return ENOTDIR.
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*
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* vop_write - Write data from uio to file at offset specified
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* in the uio, updating uio_resid to reflect the
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* amount written, and updating uio_offset to match.
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* Not allowed on directories or symlinks.
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*
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* vop_ioctl - Perform ioctl operation OP on file using data
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* DATA. The interpretation of the data is specific
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* to each ioctl.
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*
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* vop_stat - Return info about a file. The pointer is a
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* pointer to struct stat; see kern/stat.h.
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*
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* vop_gettype - Return type of file. The values for file types
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* are in kern/stattypes.h.
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*
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* vop_isseekable - Check if this file is seekable. All regular files
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* and directories are seekable, but some devices are
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* not.
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*
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* vop_fsync - Force any dirty buffers associated with this file
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* to stable storage.
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*
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* vop_mmap - Map file into memory. If you implement this
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* feature, you're responsible for choosing the
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* arguments for this operation.
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*
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* vop_truncate - Forcibly set size of file to the length passed
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* in, discarding any excess blocks.
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*
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* vop_namefile - Compute pathname relative to filesystem root
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* of the file and copy to the specified
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* uio. Need not work on objects that are not
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* directories.
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*
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*****************************************
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*
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* vop_creat - Create a regular file named NAME in the passed
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* directory DIR. If boolean EXCL is true, fail if
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* the file already exists; otherwise, use the
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* existing file if there is one. Hand back the
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* vnode for the file as per vop_lookup.
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*
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* vop_symlink - Create symlink named NAME in the passed directory,
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* with contents CONTENTS.
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*
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* vop_mkdir - Make directory NAME in the passed directory PARENTDIR.
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*
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* vop_link - Create hard link, with name NAME, to file FILE
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* in the passed directory DIR.
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*
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* vop_remove - Delete non-directory object NAME from passed
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* directory. If NAME refers to a directory,
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* return EISDIR. If passed vnode is not a
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* directory, return ENOTDIR.
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*
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* vop_rmdir - Delete directory object NAME from passed
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* directory.
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*
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* vop_rename - Rename file NAME1 in directory VN1 to be
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* file NAME2 in directory VN2.
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*
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*****************************************
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*
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* vop_lookup - Parse PATHNAME relative to the passed directory
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* DIR, and hand back the vnode for the file it
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* refers to. May destroy PATHNAME. Should increment
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* refcount on vnode handed back.
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*
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* vop_lookparent - Parse PATHNAME relative to the passed directory
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* DIR, and hand back (1) the vnode for the
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* parent directory of the file it refers to, and
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* (2) the last component of the filename, copied
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* into kernel buffer BUF with max length LEN. May
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* destroy PATHNAME. Should increment refcount on
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* vnode handed back.
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*/
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#define VOP_MAGIC 0xa2b3c4d5
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struct vnode_ops {
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unsigned long vop_magic; /* should always be VOP_MAGIC */
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int (*vop_eachopen)(struct vnode *object, int flags_from_open);
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int (*vop_reclaim)(struct vnode *vnode);
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int (*vop_read)(struct vnode *file, struct uio *uio);
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int (*vop_readlink)(struct vnode *link, struct uio *uio);
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int (*vop_getdirentry)(struct vnode *dir, struct uio *uio);
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int (*vop_write)(struct vnode *file, struct uio *uio);
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int (*vop_ioctl)(struct vnode *object, int op, userptr_t data);
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int (*vop_stat)(struct vnode *object, struct stat *statbuf);
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int (*vop_gettype)(struct vnode *object, mode_t *result);
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bool (*vop_isseekable)(struct vnode *object);
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int (*vop_fsync)(struct vnode *object);
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int (*vop_mmap)(struct vnode *file /* add stuff */);
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int (*vop_truncate)(struct vnode *file, off_t len);
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int (*vop_namefile)(struct vnode *file, struct uio *uio);
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int (*vop_creat)(struct vnode *dir,
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const char *name, bool excl, mode_t mode,
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struct vnode **result);
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int (*vop_symlink)(struct vnode *dir,
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const char *contents, const char *name);
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int (*vop_mkdir)(struct vnode *parentdir,
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const char *name, mode_t mode);
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int (*vop_link)(struct vnode *dir,
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const char *name, struct vnode *file);
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int (*vop_remove)(struct vnode *dir,
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const char *name);
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int (*vop_rmdir)(struct vnode *dir,
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const char *name);
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int (*vop_rename)(struct vnode *vn1, const char *name1,
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struct vnode *vn2, const char *name2);
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int (*vop_lookup)(struct vnode *dir,
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char *pathname, struct vnode **result);
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int (*vop_lookparent)(struct vnode *dir,
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char *pathname, struct vnode **result,
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char *buf, size_t len);
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};
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#define __VOP(vn, sym) (vnode_check(vn, #sym), (vn)->vn_ops->vop_##sym)
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#define VOP_EACHOPEN(vn, flags) (__VOP(vn, eachopen)(vn, flags))
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#define VOP_RECLAIM(vn) (__VOP(vn, reclaim)(vn))
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#define VOP_READ(vn, uio) (__VOP(vn, read)(vn, uio))
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#define VOP_READLINK(vn, uio) (__VOP(vn, readlink)(vn, uio))
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#define VOP_GETDIRENTRY(vn, uio) (__VOP(vn,getdirentry)(vn, uio))
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#define VOP_WRITE(vn, uio) (__VOP(vn, write)(vn, uio))
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#define VOP_IOCTL(vn, code, buf) (__VOP(vn, ioctl)(vn,code,buf))
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#define VOP_STAT(vn, ptr) (__VOP(vn, stat)(vn, ptr))
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#define VOP_GETTYPE(vn, result) (__VOP(vn, gettype)(vn, result))
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#define VOP_ISSEEKABLE(vn) (__VOP(vn, isseekable)(vn))
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#define VOP_FSYNC(vn) (__VOP(vn, fsync)(vn))
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#define VOP_MMAP(vn /*add stuff */) (__VOP(vn, mmap)(vn /*add stuff */))
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#define VOP_TRUNCATE(vn, pos) (__VOP(vn, truncate)(vn, pos))
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#define VOP_NAMEFILE(vn, uio) (__VOP(vn, namefile)(vn, uio))
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#define VOP_CREAT(vn,nm,excl,mode,res) (__VOP(vn, creat)(vn,nm,excl,mode,res))
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#define VOP_SYMLINK(vn, name, content) (__VOP(vn, symlink)(vn, name, content))
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#define VOP_MKDIR(vn, name, mode) (__VOP(vn, mkdir)(vn, name, mode))
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#define VOP_LINK(vn, name, vn2) (__VOP(vn, link)(vn, name, vn2))
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#define VOP_REMOVE(vn, name) (__VOP(vn, remove)(vn, name))
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#define VOP_RMDIR(vn, name) (__VOP(vn, rmdir)(vn, name))
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#define VOP_RENAME(vn1,name1,vn2,name2)(__VOP(vn1,rename)(vn1,name1,vn2,name2))
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#define VOP_LOOKUP(vn, name, res) (__VOP(vn, lookup)(vn, name, res))
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#define VOP_LOOKPARENT(vn,nm,res,bf,ln) (__VOP(vn,lookparent)(vn,nm,res,bf,ln))
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/*
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* Consistency check
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*/
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void vnode_check(struct vnode *, const char *op);
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/*
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* Reference count manipulation (handled above filesystem level)
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*/
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void vnode_incref(struct vnode *);
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void vnode_decref(struct vnode *);
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#define VOP_INCREF(vn) vnode_incref(vn)
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#define VOP_DECREF(vn) vnode_decref(vn)
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/*
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* Vnode initialization (intended for use by filesystem code)
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* The reference count is initialized to 1.
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*/
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int vnode_init(struct vnode *, const struct vnode_ops *ops,
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struct fs *fs, void *fsdata);
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/*
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* Vnode final cleanup (intended for use by filesystem code)
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* The reference count is asserted to be 1.
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*/
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void vnode_cleanup(struct vnode *);
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/*
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* Common stubs for vnode functions that just fail, in various ways.
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*/
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int vopfail_uio_notdir(struct vnode *vn, struct uio *uio);
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int vopfail_uio_isdir(struct vnode *vn, struct uio *uio);
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int vopfail_uio_inval(struct vnode *vn, struct uio *uio);
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int vopfail_uio_nosys(struct vnode *vn, struct uio *uio);
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int vopfail_mmap_isdir(struct vnode *vn /* add stuff */);
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int vopfail_mmap_perm(struct vnode *vn /* add stuff */);
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int vopfail_mmap_nosys(struct vnode *vn /* add stuff */);
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int vopfail_truncate_isdir(struct vnode *vn, off_t pos);
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int vopfail_creat_notdir(struct vnode *vn, const char *name, bool excl,
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mode_t mode, struct vnode **result);
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int vopfail_symlink_notdir(struct vnode *vn, const char *contents,
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const char *name);
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int vopfail_symlink_nosys(struct vnode *vn, const char *contents,
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const char *name);
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int vopfail_mkdir_notdir(struct vnode *vn, const char *name, mode_t mode);
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int vopfail_mkdir_nosys(struct vnode *vn, const char *name, mode_t mode);
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int vopfail_link_notdir(struct vnode *dir, const char *name,
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struct vnode *file);
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int vopfail_link_nosys(struct vnode *dir, const char *name,
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struct vnode *file);
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int vopfail_string_notdir(struct vnode *vn, const char *name);
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int vopfail_string_nosys(struct vnode *vn, const char *name);
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int vopfail_rename_notdir(struct vnode *fromdir, const char *fromname,
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struct vnode *todir, const char *toname);
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int vopfail_rename_nosys(struct vnode *fromdir, const char *fromname,
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struct vnode *todir, const char *toname);
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int vopfail_lookup_notdir(struct vnode *vn, char *path, struct vnode **result);
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int vopfail_lookparent_notdir(struct vnode *vn, char *path,
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struct vnode **result, char *buf, size_t len);
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#endif /* _VNODE_H_ */
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