Solve the fstat-wants-to-look-at-kernel-data-structures in a nicer
way: don't export the fs internals to innocent userspace programs which just want to mount the file system.
This commit is contained in:
pooka
parent
340752e10f
commit
f00b7c9b12
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@ -1,4 +1,4 @@
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/* $NetBSD: tmpfs.h,v 1.36 2008/07/28 18:00:20 pooka Exp $ */
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/* $NetBSD: tmpfs.h,v 1.37 2008/07/29 09:10:09 pooka Exp $ */
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/*
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* Copyright (c) 2005, 2006, 2007 The NetBSD Foundation, Inc.
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@ -38,11 +38,49 @@
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#include <sys/queue.h>
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#include <sys/vnode.h>
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/* --------------------------------------------------------------------- */
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/* For the kernel and anyone who likes peeking into kernel memory */
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/* --------------------------------------------------------------------- */
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#if defined(_KERNEL)
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#include <fs/tmpfs/tmpfs_pool.h>
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#include <fs/tmpfs/tmpfs_args.h>
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#endif /* defined(_KERNEL) */
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/* --------------------------------------------------------------------- */
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/*
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* Internal representation of a tmpfs directory entry.
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*/
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struct tmpfs_dirent {
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TAILQ_ENTRY(tmpfs_dirent) td_entries;
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/* Length of the name stored in this directory entry. This avoids
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* the need to recalculate it every time the name is used. */
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uint16_t td_namelen;
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/* The name of the entry, allocated from a string pool. This
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* string is not required to be zero-terminated; therefore, the
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* td_namelen field must always be used when accessing its value. */
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char * td_name;
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/* Pointer to the node this entry refers to. */
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struct tmpfs_node * td_node;
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};
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/* A directory in tmpfs holds a sorted list of directory entries, which in
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* turn point to other files (which can be directories themselves).
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*
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* In tmpfs, this list is managed by a tail queue, whose head is defined by
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* the struct tmpfs_dir type.
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*
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* It is imporant to notice that directories do not have entries for . and
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* .. as other file systems do. These can be generated when requested
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* based on information available by other means, such as the pointer to
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* the node itself in the former case or the pointer to the parent directory
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* in the latter case. This is done to simplify tmpfs's code and, more
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* importantly, to remove redundancy. */
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TAILQ_HEAD(tmpfs_dir, tmpfs_dirent);
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/* Each entry in a directory has a cookie that identifies it. Cookies
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* supersede offsets within directories because, given how tmpfs stores
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* directories in memory, there is no such thing as an offset. (Emulating
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@ -92,6 +130,7 @@
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* if they can happen at all in practice).
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*
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* XXX A nicer solution shall be attempted. */
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#if defined(_KERNEL)
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#define TMPFS_DIRCOOKIE_DOT 0
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#define TMPFS_DIRCOOKIE_DOTDOT 1
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#define TMPFS_DIRCOOKIE_EOF 2
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@ -108,9 +147,132 @@ tmpfs_dircookie(struct tmpfs_dirent *de)
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return cookie;
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}
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#endif /* defined(_KERNEL) */
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/* --------------------------------------------------------------------- */
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/*
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* Internal representation of a tmpfs file system node.
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*
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* This structure is splitted in two parts: one holds attributes common
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* to all file types and the other holds data that is only applicable to
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* a particular type. The code must be careful to only access those
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* attributes that are actually allowed by the node's type.
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*/
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struct tmpfs_node {
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/* Doubly-linked list entry which links all existing nodes for a
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* single file system. This is provided to ease the removal of
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* all nodes during the unmount operation. */
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LIST_ENTRY(tmpfs_node) tn_entries;
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/* The node's type. Any of 'VBLK', 'VCHR', 'VDIR', 'VFIFO',
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* 'VLNK', 'VREG' and 'VSOCK' is allowed. The usage of vnode
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* types instead of a custom enumeration is to make things simpler
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* and faster, as we do not need to convert between two types. */
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enum vtype tn_type;
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/* Node identifier. */
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ino_t tn_id;
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/* Node's internal status. This is used by several file system
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* operations to do modifications to the node in a delayed
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* fashion. */
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int tn_status;
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#define TMPFS_NODE_ACCESSED (1 << 1)
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#define TMPFS_NODE_MODIFIED (1 << 2)
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#define TMPFS_NODE_CHANGED (1 << 3)
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/* The node size. It does not necessarily match the real amount
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* of memory consumed by it. */
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off_t tn_size;
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/* Generic node attributes. */
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uid_t tn_uid;
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gid_t tn_gid;
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mode_t tn_mode;
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int tn_flags;
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nlink_t tn_links;
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struct timespec tn_atime;
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struct timespec tn_mtime;
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struct timespec tn_ctime;
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struct timespec tn_birthtime;
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unsigned long tn_gen;
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/* Head of byte-level lock list (used by tmpfs_advlock). */
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struct lockf * tn_lockf;
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/* As there is a single vnode for each active file within the
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* system, care has to be taken to avoid allocating more than one
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* vnode per file. In order to do this, a bidirectional association
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* is kept between vnodes and nodes.
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*
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* Whenever a vnode is allocated, its v_data field is updated to
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* point to the node it references. At the same time, the node's
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* tn_vnode field is modified to point to the new vnode representing
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* it. Further attempts to allocate a vnode for this same node will
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* result in returning a new reference to the value stored in
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* tn_vnode.
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*
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* May be NULL when the node is unused (that is, no vnode has been
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* allocated for it or it has been reclaimed). */
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kmutex_t tn_vlock;
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struct vnode * tn_vnode;
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union {
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/* Valid when tn_type == VBLK || tn_type == VCHR. */
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struct {
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dev_t tn_rdev;
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} tn_dev;
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/* Valid when tn_type == VDIR. */
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struct {
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/* Pointer to the parent directory. The root
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* directory has a pointer to itself in this field;
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* this property identifies the root node. */
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struct tmpfs_node * tn_parent;
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/* Head of a tail-queue that links the contents of
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* the directory together. See above for a
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* description of its contents. */
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struct tmpfs_dir tn_dir;
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/* Number and pointer of the first directory entry
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* returned by the readdir operation if it were
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* called again to continue reading data from the
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* same directory as before. This is used to speed
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* up reads of long directories, assuming that no
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* more than one read is in progress at a given time.
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* Otherwise, these values are discarded and a linear
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* scan is performed from the beginning up to the
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* point where readdir starts returning values. */
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off_t tn_readdir_lastn;
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struct tmpfs_dirent * tn_readdir_lastp;
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} tn_dir;
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/* Valid when tn_type == VLNK. */
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struct tn_lnk {
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/* The link's target, allocated from a string pool. */
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char * tn_link;
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} tn_lnk;
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/* Valid when tn_type == VREG. */
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struct tn_reg {
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/* The contents of regular files stored in a tmpfs
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* file system are represented by a single anonymous
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* memory object (aobj, for short). The aobj provides
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* direct access to any position within the file,
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* because its contents are always mapped in a
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* contiguous region of virtual memory. It is a task
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* of the memory management subsystem (see uvm(9)) to
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* issue the required page ins or page outs whenever
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* a position within the file is accessed. */
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struct uvm_object * tn_aobj;
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size_t tn_aobj_pages;
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} tn_reg;
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} tn_spec;
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};
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#if defined(_KERNEL)
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LIST_HEAD(tmpfs_node_list, tmpfs_node);
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/* --------------------------------------------------------------------- */
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@ -304,6 +466,23 @@ VFS_TO_TMPFS(struct mount *mp)
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return tmp;
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}
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#endif /* defined(_KERNEL) */
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static __inline
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struct tmpfs_node *
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VP_TO_TMPFS_NODE(struct vnode *vp)
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{
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struct tmpfs_node *node;
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#ifdef KASSERT
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KASSERT((vp) != NULL && (vp)->v_data != NULL);
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#endif
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node = (struct tmpfs_node *)vp->v_data;
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return node;
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}
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#if defined(_KERNEL)
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static __inline
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struct tmpfs_node *
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VP_TO_TMPFS_DIR(struct vnode *vp)
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@ -316,4 +495,6 @@ VP_TO_TMPFS_DIR(struct vnode *vp)
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#endif
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return node;
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}
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#endif /* defined(_KERNEL) */
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#endif /* _FS_TMPFS_TMPFS_H_ */
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@ -1,4 +1,4 @@
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/* $NetBSD: tmpfs_args.h,v 1.2 2008/07/28 18:00:20 pooka Exp $ */
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/* $NetBSD: tmpfs_args.h,v 1.3 2008/07/29 09:10:09 pooka Exp $ */
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/*
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* Copyright (c) 2005, 2006, 2007 The NetBSD Foundation, Inc.
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@ -33,175 +33,6 @@
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#ifndef _FS_TMPFS_TMPFS_ARGS_H_
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#define _FS_TMPFS_TMPFS_ARGS_H_
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#include <sys/vnode.h>
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/*
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* Internal representation of a tmpfs directory entry.
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*/
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struct tmpfs_dirent {
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TAILQ_ENTRY(tmpfs_dirent) td_entries;
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/* Length of the name stored in this directory entry. This avoids
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* the need to recalculate it every time the name is used. */
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uint16_t td_namelen;
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/* The name of the entry, allocated from a string pool. This
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* string is not required to be zero-terminated; therefore, the
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* td_namelen field must always be used when accessing its value. */
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char * td_name;
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/* Pointer to the node this entry refers to. */
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struct tmpfs_node * td_node;
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};
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/* A directory in tmpfs holds a sorted list of directory entries, which in
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* turn point to other files (which can be directories themselves).
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*
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* In tmpfs, this list is managed by a tail queue, whose head is defined by
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* the struct tmpfs_dir type.
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*
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* It is imporant to notice that directories do not have entries for . and
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* .. as other file systems do. These can be generated when requested
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* based on information available by other means, such as the pointer to
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* the node itself in the former case or the pointer to the parent directory
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* in the latter case. This is done to simplify tmpfs's code and, more
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* importantly, to remove redundancy. */
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TAILQ_HEAD(tmpfs_dir, tmpfs_dirent);
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/*
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* Internal representation of a tmpfs file system node.
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*
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* This structure is splitted in two parts: one holds attributes common
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* to all file types and the other holds data that is only applicable to
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* a particular type. The code must be careful to only access those
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* attributes that are actually allowed by the node's type.
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*/
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struct tmpfs_node {
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/* Doubly-linked list entry which links all existing nodes for a
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* single file system. This is provided to ease the removal of
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* all nodes during the unmount operation. */
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LIST_ENTRY(tmpfs_node) tn_entries;
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/* The node's type. Any of 'VBLK', 'VCHR', 'VDIR', 'VFIFO',
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* 'VLNK', 'VREG' and 'VSOCK' is allowed. The usage of vnode
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* types instead of a custom enumeration is to make things simpler
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* and faster, as we do not need to convert between two types. */
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enum vtype tn_type;
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/* Node identifier. */
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ino_t tn_id;
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/* Node's internal status. This is used by several file system
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* operations to do modifications to the node in a delayed
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* fashion. */
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int tn_status;
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#define TMPFS_NODE_ACCESSED (1 << 1)
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#define TMPFS_NODE_MODIFIED (1 << 2)
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#define TMPFS_NODE_CHANGED (1 << 3)
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/* The node size. It does not necessarily match the real amount
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* of memory consumed by it. */
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off_t tn_size;
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/* Generic node attributes. */
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uid_t tn_uid;
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gid_t tn_gid;
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mode_t tn_mode;
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int tn_flags;
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nlink_t tn_links;
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struct timespec tn_atime;
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struct timespec tn_mtime;
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struct timespec tn_ctime;
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struct timespec tn_birthtime;
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unsigned long tn_gen;
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/* Head of byte-level lock list (used by tmpfs_advlock). */
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struct lockf * tn_lockf;
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/* As there is a single vnode for each active file within the
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* system, care has to be taken to avoid allocating more than one
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* vnode per file. In order to do this, a bidirectional association
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* is kept between vnodes and nodes.
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*
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* Whenever a vnode is allocated, its v_data field is updated to
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* point to the node it references. At the same time, the node's
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* tn_vnode field is modified to point to the new vnode representing
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* it. Further attempts to allocate a vnode for this same node will
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* result in returning a new reference to the value stored in
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* tn_vnode.
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*
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* May be NULL when the node is unused (that is, no vnode has been
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* allocated for it or it has been reclaimed). */
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kmutex_t tn_vlock;
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struct vnode * tn_vnode;
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union {
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/* Valid when tn_type == VBLK || tn_type == VCHR. */
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struct {
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dev_t tn_rdev;
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} tn_dev;
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/* Valid when tn_type == VDIR. */
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struct {
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/* Pointer to the parent directory. The root
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* directory has a pointer to itself in this field;
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* this property identifies the root node. */
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struct tmpfs_node * tn_parent;
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/* Head of a tail-queue that links the contents of
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* the directory together. See above for a
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* description of its contents. */
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struct tmpfs_dir tn_dir;
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/* Number and pointer of the first directory entry
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* returned by the readdir operation if it were
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* called again to continue reading data from the
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* same directory as before. This is used to speed
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* up reads of long directories, assuming that no
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* more than one read is in progress at a given time.
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* Otherwise, these values are discarded and a linear
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* scan is performed from the beginning up to the
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* point where readdir starts returning values. */
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off_t tn_readdir_lastn;
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struct tmpfs_dirent * tn_readdir_lastp;
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} tn_dir;
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/* Valid when tn_type == VLNK. */
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struct tn_lnk {
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/* The link's target, allocated from a string pool. */
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char * tn_link;
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} tn_lnk;
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/* Valid when tn_type == VREG. */
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struct tn_reg {
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/* The contents of regular files stored in a tmpfs
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* file system are represented by a single anonymous
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* memory object (aobj, for short). The aobj provides
|
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* direct access to any position within the file,
|
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* because its contents are always mapped in a
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* contiguous region of virtual memory. It is a task
|
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* of the memory management subsystem (see uvm(9)) to
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* issue the required page ins or page outs whenever
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* a position within the file is accessed. */
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struct uvm_object * tn_aobj;
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size_t tn_aobj_pages;
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} tn_reg;
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} tn_spec;
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};
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static __inline
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struct tmpfs_node *
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VP_TO_TMPFS_NODE(struct vnode *vp)
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{
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struct tmpfs_node *node;
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#ifdef KASSERT
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KASSERT((vp) != NULL && (vp)->v_data != NULL);
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#endif
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node = (struct tmpfs_node *)vp->v_data;
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return node;
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}
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/*
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* This structure is used to communicate mount parameters between userland
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* and kernel space.
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|
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@ -1,4 +1,4 @@
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/* $NetBSD: tmpfs_vfsops.c,v 1.43 2008/07/28 18:00:20 pooka Exp $ */
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/* $NetBSD: tmpfs_vfsops.c,v 1.44 2008/07/29 09:10:09 pooka Exp $ */
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/*
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* Copyright (c) 2005, 2006, 2007 The NetBSD Foundation, Inc.
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@ -42,7 +42,7 @@
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: tmpfs_vfsops.c,v 1.43 2008/07/28 18:00:20 pooka Exp $");
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__KERNEL_RCSID(0, "$NetBSD: tmpfs_vfsops.c,v 1.44 2008/07/29 09:10:09 pooka Exp $");
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#include <sys/param.h>
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#include <sys/types.h>
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@ -56,6 +56,7 @@ __KERNEL_RCSID(0, "$NetBSD: tmpfs_vfsops.c,v 1.43 2008/07/28 18:00:20 pooka Exp
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#include <miscfs/genfs/genfs.h>
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#include <fs/tmpfs/tmpfs.h>
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#include <fs/tmpfs/tmpfs_args.h>
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MODULE(MODULE_CLASS_VFS, tmpfs, NULL);
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@ -1,4 +1,4 @@
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/* $NetBSD: tmpfs.c,v 1.6 2008/07/28 18:05:09 pooka Exp $ */
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/* $NetBSD: tmpfs.c,v 1.7 2008/07/29 09:10:09 pooka Exp $ */
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/*-
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* Copyright (c) 2006 The NetBSD Foundation, Inc.
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@ -27,7 +27,7 @@
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*/
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#include <sys/cdefs.h>
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__RCSID("$NetBSD: tmpfs.c,v 1.6 2008/07/28 18:05:09 pooka Exp $");
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||||
__RCSID("$NetBSD: tmpfs.c,v 1.7 2008/07/29 09:10:09 pooka Exp $");
|
||||
|
||||
#include <sys/types.h>
|
||||
#include <sys/param.h>
|
||||
|
|
@ -37,7 +37,7 @@ __RCSID("$NetBSD: tmpfs.c,v 1.6 2008/07/28 18:05:09 pooka Exp $");
|
|||
#include <sys/vnode.h>
|
||||
#include <sys/mount.h>
|
||||
|
||||
#include <fs/tmpfs/tmpfs_args.h>
|
||||
#include <fs/tmpfs/tmpfs.h>
|
||||
|
||||
#include <err.h>
|
||||
#include <kvm.h>
|
||||
|
|
|
|||
Loading…
Reference in New Issue