249 lines
11 KiB
C
249 lines
11 KiB
C
#ifndef __KERN_FS_VFS_INODE_H__
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#define __KERN_FS_VFS_INODE_H__
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#include <defs.h>
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#include <dev.h>
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#include <sfs.h>
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#include <atomic.h>
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#include <assert.h>
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struct stat;
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struct iobuf;
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/*
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* A struct inode is an abstract representation of a file.
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*
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* It is an interface that allows the kernel's filesystem-independent
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* code to interact usefully with multiple sets 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: in_info is Filesystem-specific data, in_type is the inode type
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*
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* open_count is managed using VOP_INCOPEN and VOP_DECOPEN by
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* vfs_open() and vfs_close(). Code above the VFS layer should not
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* need to worry about it.
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*/
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struct inode {
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union {
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struct device __device_info;
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struct sfs_inode __sfs_inode_info;
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} in_info;
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enum {
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inode_type_device_info = 0x1234,
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inode_type_sfs_inode_info,
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} in_type;
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int ref_count;
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int open_count;
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struct fs *in_fs;
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const struct inode_ops *in_ops;
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};
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#define __in_type(type) inode_type_##type##_info
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#define check_inode_type(node, type) ((node)->in_type == __in_type(type))
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#define __vop_info(node, type) \
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({ \
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struct inode *__node = (node); \
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assert(__node != NULL && check_inode_type(__node, type)); \
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&(__node->in_info.__##type##_info); \
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})
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#define vop_info(node, type) __vop_info(node, type)
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#define info2node(info, type) \
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to_struct((info), struct inode, in_info.__##type##_info)
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struct inode *__alloc_inode(int type);
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#define alloc_inode(type) __alloc_inode(__in_type(type))
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#define MAX_INODE_COUNT 0x10000
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int inode_ref_inc(struct inode *node);
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int inode_ref_dec(struct inode *node);
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int inode_open_inc(struct inode *node);
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int inode_open_dec(struct inode *node);
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void inode_init(struct inode *node, const struct inode_ops *ops, struct fs *fs);
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void inode_kill(struct inode *node);
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#define VOP_MAGIC 0x8c4ba476
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/*
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* Abstract operations on a inode.
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*
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* These are used in the form VOP_FOO(inode, args), which are macros
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* that expands to inode->inode_ops->vop_foo(inode, args). The operations
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* "foo" are:
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*
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* vop_open - Called on 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 inode 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 inodes.
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* This maintains the open count so VOP_LASTCLOSE can
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* be called at the right time.
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*
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* vop_close - To be called on *last* close() of a file.
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*
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* VOP_LASTCLOSE should not be called directly from
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* above the VFS layer - use vfs_close() to close
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* inodes opened with vfs_open().
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*
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* vop_reclaim - Called when inode is no longer in use. Note that
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* this may be substantially after vop_lastclose is
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* called.
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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_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_fstat -Return info about a file. The pointer is a
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* pointer to struct stat; see 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 sfs.h.
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*
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* vop_tryseek - Check if seeking to the specified position within
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* the file is legal. (For instance, all seeks
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* are illegal on serial port devices, and seeks
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* past EOF on files whose sizes are fixed may be
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* as well.)
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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_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 io buffer.
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* 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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* inode for the file as per vop_lookup.
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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 inode for the file it
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* refers to. May destroy PATHNAME. Should increment
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* refcount on inode handed back.
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*/
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struct inode_ops {
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unsigned long vop_magic;
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int (*vop_open)(struct inode *node, uint32_t open_flags);
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int (*vop_close)(struct inode *node);
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int (*vop_read)(struct inode *node, struct iobuf *iob);
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int (*vop_write)(struct inode *node, struct iobuf *iob);
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int (*vop_fstat)(struct inode *node, struct stat *stat);
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int (*vop_fsync)(struct inode *node);
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int (*vop_namefile)(struct inode *node, struct iobuf *iob);
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int (*vop_getdirentry)(struct inode *node, struct iobuf *iob);
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int (*vop_reclaim)(struct inode *node);
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int (*vop_gettype)(struct inode *node, uint32_t *type_store);
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int (*vop_tryseek)(struct inode *node, off_t pos);
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int (*vop_truncate)(struct inode *node, off_t len);
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int (*vop_create)(struct inode *node, const char *name, bool excl, struct inode **node_store);
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int (*vop_lookup)(struct inode *node, char *path, struct inode **node_store);
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int (*vop_ioctl)(struct inode *node, int op, void *data);
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};
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/*
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* Consistency check
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*/
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void inode_check(struct inode *node, const char *opstr);
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#define __vop_op(node, sym) \
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({ \
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struct inode *__node = (node); \
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assert(__node != NULL && __node->in_ops != NULL && __node->in_ops->vop_##sym != NULL); \
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inode_check(__node, #sym); \
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__node->in_ops->vop_##sym; \
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})
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#define vop_open(node, open_flags) (__vop_op(node, open)(node, open_flags))
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#define vop_close(node) (__vop_op(node, close)(node))
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#define vop_read(node, iob) (__vop_op(node, read)(node, iob))
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#define vop_write(node, iob) (__vop_op(node, write)(node, iob))
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#define vop_fstat(node, stat) (__vop_op(node, fstat)(node, stat))
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#define vop_fsync(node) (__vop_op(node, fsync)(node))
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#define vop_namefile(node, iob) (__vop_op(node, namefile)(node, iob))
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#define vop_getdirentry(node, iob) (__vop_op(node, getdirentry)(node, iob))
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#define vop_reclaim(node) (__vop_op(node, reclaim)(node))
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#define vop_ioctl(node, op, data) (__vop_op(node, ioctl)(node, op, data))
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#define vop_gettype(node, type_store) (__vop_op(node, gettype)(node, type_store))
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#define vop_tryseek(node, pos) (__vop_op(node, tryseek)(node, pos))
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#define vop_truncate(node, len) (__vop_op(node, truncate)(node, len))
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#define vop_create(node, name, excl, node_store) (__vop_op(node, create)(node, name, excl, node_store))
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#define vop_lookup(node, path, node_store) (__vop_op(node, lookup)(node, path, node_store))
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#define vop_fs(node) ((node)->in_fs)
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#define vop_init(node, ops, fs) inode_init(node, ops, fs)
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#define vop_kill(node) inode_kill(node)
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/*
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* Reference count manipulation (handled above filesystem level)
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*/
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#define vop_ref_inc(node) inode_ref_inc(node)
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#define vop_ref_dec(node) inode_ref_dec(node)
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/*
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* Open count manipulation (handled above filesystem level)
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*
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* VOP_INCOPEN is called by vfs_open. VOP_DECOPEN is called by vfs_close.
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* Neither of these should need to be called from above the vfs layer.
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*/
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#define vop_open_inc(node) inode_open_inc(node)
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#define vop_open_dec(node) inode_open_dec(node)
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static inline int
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inode_ref_count(struct inode *node) {
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return node->ref_count;
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}
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static inline int
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inode_open_count(struct inode *node) {
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return node->open_count;
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}
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#endif /* !__KERN_FS_VFS_INODE_H__ */
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