/* $NetBSD: tmpfs.h,v 1.26 2007/02/22 06:37:00 thorpej Exp $ */
/*-
* SPDX-License-Identifier: BSD-2-Clause
*
* Copyright (c) 2005, 2006 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Julio M. Merino Vidal, developed as part of Google's Summer of Code
* 2005 program.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
* $FreeBSD$
*/
#ifndef _FS_TMPFS_TMPFS_H_
#define _FS_TMPFS_TMPFS_H_
#include <sys/cdefs.h>
#include <sys/queue.h>
#include <sys/tree.h>
#ifdef _SYS_MALLOC_H_
MALLOC_DECLARE(M_TMPFSNAME);
#endif
#define OBJ_TMPFS OBJ_PAGERPRIV1 /* has tmpfs vnode allocated */
#define OBJ_TMPFS_VREF OBJ_PAGERPRIV2 /* vnode is referenced */
/*
* Internal representation of a tmpfs directory entry.
*/
LIST_HEAD(tmpfs_dir_duphead, tmpfs_dirent);
struct tmpfs_dirent {
/*
* Depending on td_cookie flag entry can be of 3 types:
* - regular -- no hash collisions, stored in RB-Tree
* - duphead -- synthetic linked list head for dup entries
* - dup -- stored in linked list instead of RB-Tree
*/
union {
/* regular and duphead entry types */
RB_ENTRY(tmpfs_dirent) td_entries;
/* dup entry type */
struct {
LIST_ENTRY(tmpfs_dirent) entries;
LIST_ENTRY(tmpfs_dirent) index_entries;
} td_dup;
} uh;
uint32_t td_cookie;
uint32_t td_hash;
u_int td_namelen;
/*
* Pointer to the node this entry refers to. In case this field
* is NULL, the node is a whiteout.
*/
struct tmpfs_node * td_node;
union {
/*
* The name of the entry, allocated from a string pool. This
* string is not required to be zero-terminated.
*/
char * td_name; /* regular, dup */
struct tmpfs_dir_duphead td_duphead; /* duphead */
} ud;
};
/*
* A directory in tmpfs holds a collection of directory entries, which
* in turn point to other files (which can be directories themselves).
*
* In tmpfs, this collection is managed by a RB-Tree, whose head is
* defined by the struct tmpfs_dir type.
*
* It is important to notice that directories do not have entries for . and
* .. as other file systems do. These can be generated when requested
* based on information available by other means, such as the pointer to
* the node itself in the former case or the pointer to the parent directory
* in the latter case. This is done to simplify tmpfs's code and, more
* importantly, to remove redundancy.
*/
RB_HEAD(tmpfs_dir, tmpfs_dirent);
/*
* Each entry in a directory has a cookie that identifies it. Cookies
* supersede offsets within directories because, given how tmpfs stores
* directories in memory, there is no such thing as an offset.
*
* The '.', '..' and the end of directory markers have fixed cookies which
* cannot collide with the cookies generated by other entries. The cookies
* for the other entries are generated based on the file name hash value or
* unique number in case of name hash collision.
*
* To preserve compatibility cookies are limited to 31 bits.
*/
#define TMPFS_DIRCOOKIE_DOT 0
#define TMPFS_DIRCOOKIE_DOTDOT 1
#define TMPFS_DIRCOOKIE_EOF 2
#define TMPFS_DIRCOOKIE_MASK ((off_t)0x3fffffffU)
#define TMPFS_DIRCOOKIE_MIN ((off_t)0x00000004U)
#define TMPFS_DIRCOOKIE_DUP ((off_t)0x40000000U)
#define TMPFS_DIRCOOKIE_DUPHEAD ((off_t)0x80000000U)
#define TMPFS_DIRCOOKIE_DUP_MIN TMPFS_DIRCOOKIE_DUP
#define TMPFS_DIRCOOKIE_DUP_MAX \
(TMPFS_DIRCOOKIE_DUP | TMPFS_DIRCOOKIE_MASK)
/*
* Internal representation of a tmpfs extended attribute entry.
*/
LIST_HEAD(tmpfs_extattr_list, tmpfs_extattr);
struct tmpfs_extattr {
LIST_ENTRY(tmpfs_extattr) ea_extattrs;
int ea_namespace; /* attr namespace */
char *ea_name; /* attr name */
unsigned char ea_namelen; /* attr name length */
char *ea_value; /* attr value buffer */
ssize_t ea_size; /* attr value size */
};
/*
* Internal representation of a tmpfs file system node.
*
* This structure is splitted in two parts: one holds attributes common
* to all file types and the other holds data that is only applicable to
* a particular type. The code must be careful to only access those
* attributes that are actually allowed by the node's type.
*
* Below is the key of locks used to protected the fields in the following
* structures.
* (v) vnode lock in exclusive mode
* (vi) vnode lock in exclusive mode, or vnode lock in shared vnode and
* tn_interlock
* (i) tn_interlock
* (m) tmpfs_mount tm_allnode_lock
* (c) stable after creation
* (v) tn_reg.tn_aobj vm_object lock
*/
struct tmpfs_node {
/*
* Doubly-linked list entry which links all existing nodes for
* a single file system. This is provided to ease the removal
* of all nodes during the unmount operation, and to support
* the implementation of VOP_VNTOCNP(). tn_attached is false
* when the node is removed from list and unlocked.
*/
LIST_ENTRY(tmpfs_node) tn_entries; /* (m) */
/* Node identifier. */
ino_t tn_id; /* (c) */
/*
* The node's type. Any of 'VBLK', 'VCHR', 'VDIR', 'VFIFO',
* 'VLNK', 'VREG' and 'VSOCK' is allowed. The usage of vnode
* types instead of a custom enumeration is to make things simpler
* and faster, as we do not need to convert between two types.
*/
enum vtype tn_type; /* (c) */
/*
* See the top comment. Reordered here to fill LP64 hole.
*/
bool tn_attached; /* (m) */
/*
* Node's internal status. This is used by several file system
* operations to do modifications to the node in a delayed
* fashion.
*
* tn_accessed has a dedicated byte to allow update by store without
* using atomics. This provides a micro-optimization to e.g.
* tmpfs_read_pgcache().
*/
uint8_t tn_status; /* (vi) */
uint8_t tn_accessed; /* unlocked */
/*
* The node size. It does not necessarily match the real amount
* of memory consumed by it.
*/
off_t tn_size; /* (v) */
/* Generic node attributes. */
uid_t tn_uid; /* (v) */
gid_t tn_gid; /* (v) */
mode_t tn_mode; /* (v) */
int tn_links; /* (v) */
u_long tn_flags; /* (v) */
struct timespec tn_atime; /* (vi) */
struct timespec tn_mtime; /* (vi) */
struct timespec tn_ctime; /* (vi) */
struct timespec tn_birthtime; /* (v) */
unsigned long tn_gen; /* (c) */
/*
* As there is a single vnode for each active file within the
* system, care has to be taken to avoid allocating more than one
* vnode per file. In order to do this, a bidirectional association
* is kept between vnodes and nodes.
*
* Whenever a vnode is allocated, its v_data field is updated to
* point to the node it references. At the same time, the node's
* tn_vnode field is modified to point to the new vnode representing
* it. Further attempts to allocate a vnode for this same node will
* result in returning a new reference to the value stored in
* tn_vnode.
*
* May be NULL when the node is unused (that is, no vnode has been
* allocated for it or it has been reclaimed).
*/
struct vnode * tn_vnode; /* (i) */
/*
* Interlock to protect tn_vpstate, and tn_status under shared
* vnode lock.
*/
struct mtx tn_interlock;
/*
* Identify if current node has vnode assiocate with
* or allocating vnode.
*/
int tn_vpstate; /* (i) */
/* Transient refcounter on this node. */
u_int tn_refcount; /* 0<->1 (m) + (i) */
/* Extended attributes of this node. */
struct tmpfs_extattr_list tn_extattrs; /* (v) */
/* misc data field for different tn_type node */
union {
/* Valid when tn_type == VBLK || tn_type == VCHR. */
dev_t tn_rdev; /* (c) */
/* Valid when tn_type == VDIR. */
struct tn_dir {
/*
* Pointer to the parent directory. The root
* directory has a pointer to itself in this field;
* this property identifies the root node.
*/
struct tmpfs_node * tn_parent;
/*
* Head of a tree that links the contents of
* the directory together.
*/
struct tmpfs_dir tn_dirhead;
/*
* Head of a list the contains fake directory entries
* heads, i.e. entries with TMPFS_DIRCOOKIE_DUPHEAD
* flag.
*/
struct tmpfs_dir_duphead tn_dupindex;
/*
* Number and pointer of the first directory entry
* returned by the readdir operation if it were
* called again to continue reading data from the
* same directory as before. This is used to speed
* up reads of long directories, assuming that no
* more than one read is in progress at a given time.
* Otherwise, these values are discarded.
*/
off_t tn_readdir_lastn;
struct tmpfs_dirent * tn_readdir_lastp;
} tn_dir;
/* Valid when tn_type == VLNK. */
/* The link's target, allocated from a string pool. */
struct tn_link {
char * tn_link_target; /* (c) */
char tn_link_smr; /* (c) */
} tn_link;
/* Valid when tn_type == VREG. */
struct tn_reg {
/*
* The contents of regular files stored in a
* tmpfs file system are represented by a
* single anonymous memory object (aobj, for
* short). The aobj provides direct access to
* any position within the file. It is a task
* of the memory management subsystem to issue
* the required page ins or page outs whenever
* a position within the file is accessed.
*/
vm_object_t tn_aobj; /* (c) */
struct tmpfs_mount *tn_tmp; /* (c) */
vm_pindex_t tn_pages; /* (v) */
} tn_reg;
} tn_spec; /* (v) */
};
LIST_HEAD(tmpfs_node_list, tmpfs_node);
#define tn_rdev tn_spec.tn_rdev
#define tn_dir tn_spec.tn_dir
#define tn_link_target tn_spec.tn_link.tn_link_target
#define tn_link_smr tn_spec.tn_link.tn_link_smr
#define tn_reg tn_spec.tn_reg
#define tn_fifo tn_spec.tn_fifo
#define TMPFS_LINK_MAX INT_MAX
#define TMPFS_NODE_LOCK(node) mtx_lock(&(node)->tn_interlock)
#define TMPFS_NODE_UNLOCK(node) mtx_unlock(&(node)->tn_interlock)
#define TMPFS_NODE_MTX(node) (&(node)->tn_interlock)
#define TMPFS_NODE_ASSERT_LOCKED(node) mtx_assert(TMPFS_NODE_MTX(node), \
MA_OWNED)
#ifdef INVARIANTS
#define TMPFS_ASSERT_LOCKED(node) do { \
MPASS((node) != NULL); \
MPASS((node)->tn_vnode != NULL); \
ASSERT_VOP_LOCKED((node)->tn_vnode, "tmpfs assert"); \
} while (0)
#else
#define TMPFS_ASSERT_LOCKED(node) (void)0
#endif
/* tn_vpstate */
#define TMPFS_VNODE_ALLOCATING 1
#define TMPFS_VNODE_WANT 2
#define TMPFS_VNODE_DOOMED 4
#define TMPFS_VNODE_WRECLAIM 8
/* tn_status */
#define TMPFS_NODE_MODIFIED 0x01
#define TMPFS_NODE_CHANGED 0x02
/*
* Internal representation of a tmpfs mount point.
*/
struct tmpfs_mount {
/*
* Original value of the "size" parameter, for reference purposes,
* mostly.
*/
off_t tm_size_max;
/*
* Maximum number of memory pages available for use by the file
* system, set during mount time. This variable must never be
* used directly as it may be bigger than the current amount of
* free memory; in the extreme case, it will hold the ULONG_MAX
* value.
*/
u_long tm_pages_max;
/* Number of pages in use by the file system. */
u_long tm_pages_used;
/*
* Pointer to the node representing the root directory of this
* file system.
*/
struct tmpfs_node * tm_root;
/*
* Maximum number of possible nodes for this file system; set
* during mount time. We need a hard limit on the maximum number
* of nodes to avoid allocating too much of them; their objects
* cannot be released until the file system is unmounted.
* Otherwise, we could easily run out of memory by creating lots
* of empty files and then simply removing them.
*/
ino_t tm_nodes_max;
/* unrhdr used to allocate inode numbers */
struct unrhdr64 tm_ino_unr;
/* Number of nodes currently that are in use. */
ino_t tm_nodes_inuse;
/* Memory used by extended attributes */
uint64_t tm_ea_memory_inuse;
/* Maximum memory available for extended attributes */
uint64_t tm_ea_memory_max;
/* Refcounter on this struct tmpfs_mount. */
uint64_t tm_refcount;
/* maximum representable file size */
u_int64_t tm_maxfilesize;
/*
* The used list contains all nodes that are currently used by
* the file system; i.e., they refer to existing files.
*/
struct tmpfs_node_list tm_nodes_used;
/* All node lock to protect the node list and tmp_pages_used. */
struct mtx tm_allnode_lock;
/* Read-only status. */
bool tm_ronly;
/* Do not use namecache. */
bool tm_nonc;
/* Do not update mtime on writes through mmaped areas. */
bool tm_nomtime;
};
#define TMPFS_LOCK(tm) mtx_lock(&(tm)->tm_allnode_lock)
#define TMPFS_UNLOCK(tm) mtx_unlock(&(tm)->tm_allnode_lock)
#define TMPFS_MP_ASSERT_LOCKED(tm) mtx_assert(&(tm)->tm_allnode_lock, MA_OWNED)
/*
* This structure maps a file identifier to a tmpfs node. Used by the
* NFS code.
*/
struct tmpfs_fid_data {
ino_t tfd_id;
unsigned long tfd_gen;
};
_Static_assert(sizeof(struct tmpfs_fid_data) <= MAXFIDSZ,
"(struct tmpfs_fid_data) is larger than (struct fid).fid_data");
struct tmpfs_dir_cursor {
struct tmpfs_dirent *tdc_current;
struct tmpfs_dirent *tdc_tree;
};
#ifdef _KERNEL
/*
* Prototypes for tmpfs_subr.c.
*/
void tmpfs_ref_node(struct tmpfs_node *node);
int tmpfs_alloc_node(struct mount *mp, struct tmpfs_mount *, enum vtype,
uid_t uid, gid_t gid, mode_t mode, struct tmpfs_node *,
const char *, dev_t, struct tmpfs_node **);
int tmpfs_fo_close(struct file *fp, struct thread *td);
void tmpfs_free_node(struct tmpfs_mount *, struct tmpfs_node *);
bool tmpfs_free_node_locked(struct tmpfs_mount *, struct tmpfs_node *, bool);
void tmpfs_free_tmp(struct tmpfs_mount *);
int tmpfs_alloc_dirent(struct tmpfs_mount *, struct tmpfs_node *,
const char *, u_int, struct tmpfs_dirent **);
void tmpfs_free_dirent(struct tmpfs_mount *, struct tmpfs_dirent *);
void tmpfs_dirent_init(struct tmpfs_dirent *, const char *, u_int);
void tmpfs_destroy_vobject(struct vnode *vp, vm_object_t obj);
int tmpfs_alloc_vp(struct mount *, struct tmpfs_node *, int,
struct vnode **);
void tmpfs_free_vp(struct vnode *);
int tmpfs_alloc_file(struct vnode *, struct vnode **, struct vattr *,
struct componentname *, const char *);
void tmpfs_check_mtime(struct vnode *);
void tmpfs_dir_attach(struct vnode *, struct tmpfs_dirent *);
void tmpfs_dir_detach(struct vnode *, struct tmpfs_dirent *);
void tmpfs_dir_destroy(struct tmpfs_mount *, struct tmpfs_node *);
struct tmpfs_dirent * tmpfs_dir_lookup(struct tmpfs_node *node,
struct tmpfs_node *f,
struct componentname *cnp);
int tmpfs_dir_getdents(struct tmpfs_mount *, struct tmpfs_node *,
struct uio *, int, uint64_t *, int *);
int tmpfs_dir_whiteout_add(struct vnode *, struct componentname *);
void tmpfs_dir_whiteout_remove(struct vnode *, struct componentname *);
int tmpfs_reg_resize(struct vnode *, off_t, boolean_t);
int tmpfs_reg_punch_hole(struct vnode *vp, off_t *, off_t *);
int tmpfs_chflags(struct vnode *, u_long, struct ucred *, struct thread *);
int tmpfs_chmod(struct vnode *, mode_t, struct ucred *, struct thread *);
int tmpfs_chown(struct vnode *, uid_t, gid_t, struct ucred *,
struct thread *);
int tmpfs_chsize(struct vnode *, u_quad_t, struct ucred *, struct thread *);
int tmpfs_chtimes(struct vnode *, struct vattr *, struct ucred *cred,
struct thread *);
void tmpfs_itimes(struct vnode *, const struct timespec *,
const struct timespec *);
void tmpfs_set_accessed(struct tmpfs_mount *tm, struct tmpfs_node *node);
void tmpfs_set_status(struct tmpfs_mount *tm, struct tmpfs_node *node,
int status);
int tmpfs_truncate(struct vnode *, off_t);
struct tmpfs_dirent *tmpfs_dir_first(struct tmpfs_node *dnode,
struct tmpfs_dir_cursor *dc);
struct tmpfs_dirent *tmpfs_dir_next(struct tmpfs_node *dnode,
struct tmpfs_dir_cursor *dc);
bool tmpfs_pages_check_avail(struct tmpfs_mount *tmp, size_t req_pages);
void tmpfs_extattr_free(struct tmpfs_extattr* ea);
static __inline void
tmpfs_update(struct vnode *vp)
{
tmpfs_itimes(vp, NULL, NULL);
}
/*
* Convenience macros to simplify some logical expressions.
*/
#define IMPLIES(a, b) (!(a) || (b))
/*
* Checks that the directory entry pointed by 'de' matches the name 'name'
* with a length of 'len'.
*/
#define TMPFS_DIRENT_MATCHES(de, name, len) \
(de->td_namelen == len && \
bcmp((de)->ud.td_name, (name), (de)->td_namelen) == 0)
/*
* Ensures that the node pointed by 'node' is a directory and that its
* contents are consistent with respect to directories.
*/
#define TMPFS_VALIDATE_DIR(node) do { \
MPASS((node)->tn_type == VDIR); \
MPASS((node)->tn_size % sizeof(struct tmpfs_dirent) == 0); \
} while (0)
/*
* Amount of memory pages to reserve for the system (e.g., to not use by
* tmpfs).
*/
#if !defined(TMPFS_PAGES_MINRESERVED)
#define TMPFS_PAGES_MINRESERVED (4 * 1024 * 1024 / PAGE_SIZE)
#endif
/*
* Amount of memory to reserve for extended attributes.
*/
#if !defined(TMPFS_EA_MEMORY_RESERVED)
#define TMPFS_EA_MEMORY_RESERVED (16 * 1024 * 1024)
#endif
size_t tmpfs_mem_avail(void);
size_t tmpfs_pages_used(struct tmpfs_mount *tmp);
int tmpfs_subr_init(void);
void tmpfs_subr_uninit(void);
extern int tmpfs_pager_type;
/*
* Macros/functions to convert from generic data structures to tmpfs
* specific ones.
*/
static inline struct vnode *
VM_TO_TMPFS_VP(vm_object_t obj)
{
struct tmpfs_node *node;
if ((obj->flags & OBJ_TMPFS) == 0)
return (NULL);
/*
* swp_priv is the back-pointer to the tmpfs node, if any,
* which uses the vm object as backing store. The object
* handle is not used to avoid locking sw_alloc_sx on tmpfs
* node instantiation/destroy.
*/
node = obj->un_pager.swp.swp_priv;
return (node->tn_vnode);
}
static inline struct tmpfs_mount *
VM_TO_TMPFS_MP(vm_object_t obj)
{
struct tmpfs_node *node;
if ((obj->flags & OBJ_TMPFS) == 0)
return (NULL);
node = obj->un_pager.swp.swp_priv;
MPASS(node->tn_type == VREG);
return (node->tn_reg.tn_tmp);
}
static inline struct tmpfs_mount *
VFS_TO_TMPFS(struct mount *mp)
{
struct tmpfs_mount *tmp;
MPASS(mp != NULL && mp->mnt_data != NULL);
tmp = (struct tmpfs_mount *)mp->mnt_data;
return (tmp);
}
static inline struct tmpfs_node *
VP_TO_TMPFS_NODE(struct vnode *vp)
{
struct tmpfs_node *node;
MPASS(vp != NULL && vp->v_data != NULL);
node = (struct tmpfs_node *)vp->v_data;
return (node);
}
#define VP_TO_TMPFS_NODE_SMR(vp) \
((struct tmpfs_node *)vn_load_v_data_smr(vp))
static inline struct tmpfs_node *
VP_TO_TMPFS_DIR(struct vnode *vp)
{
struct tmpfs_node *node;
node = VP_TO_TMPFS_NODE(vp);
TMPFS_VALIDATE_DIR(node);
return (node);
}
static inline bool
tmpfs_use_nc(struct vnode *vp)
{
return (!(VFS_TO_TMPFS(vp->v_mount)->tm_nonc));
}
static inline void
tmpfs_update_getattr(struct vnode *vp)
{
struct tmpfs_node *node;
node = VP_TO_TMPFS_NODE(vp);
if (__predict_false((node->tn_status & (TMPFS_NODE_MODIFIED |
TMPFS_NODE_CHANGED)) != 0 || node->tn_accessed))
tmpfs_update(vp);
}
extern struct fileops tmpfs_fnops;
#endif /* _KERNEL */
#endif /* _FS_TMPFS_TMPFS_H_ */
