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freebsd-skq/sys/fs/tmpfs/tmpfs.h

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MFp4: Add tmpfs, an efficient memory file system. Please note that, this is currently considered as an experimental feature so there could be some rough edges. Consult http://wiki.freebsd.org/TMPFS for more information. For now, connect tmpfs to build on i386 and amd64 architectures only. Please let us know if you have success with other platforms. This work was developed by Julio M. Merino Vidal for NetBSD as a SoC project; Rohit Jalan ported it from NetBSD to FreeBSD. Howard Su and Glen Leeder are worked on it to continue this effort. Obtained from: NetBSD via p4 Submitted by: Howard Su (with some minor changes) Approved by: re (kensmith)
2007-06-16 01:56:05 +00:00
/* $NetBSD: tmpfs.h,v 1.14 2006/02/10 16:00:02 christos Exp $ */
/*
* Copyright (c) 2005 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.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the NetBSD
* Foundation, Inc. and its contributors.
* 4. Neither the name of The NetBSD Foundation nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* 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_
/* ---------------------------------------------------------------------
* KERNEL-SPECIFIC DEFINITIONS
* --------------------------------------------------------------------- */
#include <sys/dirent.h>
#include <sys/mount.h>
#include <sys/queue.h>
#include <sys/vnode.h>
#include <sys/file.h>
#include <sys/lock.h>
#include <sys/mutex.h>
/* --------------------------------------------------------------------- */
#include <sys/malloc.h>
#include <sys/systm.h>
#include <sys/vmmeter.h>
#include <vm/swap_pager.h>
MALLOC_DECLARE(M_TMPFSMNT);
#include <fs/tmpfs/tmpfs_uma.h>
/* --------------------------------------------------------------------- */
/*
* Internal representation of a tmpfs directory entry.
*/
struct tmpfs_dirent {
TAILQ_ENTRY(tmpfs_dirent) td_entries;
/* Length of the name stored in this directory entry. This avoids
* the need to recalculate it every time the name is used. */
uint16_t td_namelen;
/* The name of the entry, allocated from a string pool. This
* string is not required to be zero-terminated; therefore, the
* td_namelen field must always be used when accessing its value. */
char * td_name;
/* Pointer to the node this entry refers to. */
struct tmpfs_node * td_node;
};
/* A directory in tmpfs holds a sorted list of directory entries, which in
* turn point to other files (which can be directories themselves).
*
* In tmpfs, this list is managed by a tail queue, whose head is defined by
* the struct tmpfs_dir type.
*
* It is imporant 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. */
TAILQ_HEAD(tmpfs_dir, tmpfs_dirent);
#define TMPFS_DIRCOOKIE(dirent) ((off_t)(uintptr_t)(dirent))
#define TMPFS_DIRCOOKIE_DOT 0
#define TMPFS_DIRCOOKIE_DOTDOT 1
#define TMPFS_DIRCOOKIE_EOF 2
/* --------------------------------------------------------------------- */
/*
* 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.
*
*/
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. */
LIST_ENTRY(tmpfs_node) tn_entries;
/* 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;
/* Node identifier. */
ino_t tn_id;
/* Node's internal status. This is used by several file system
* operations to do modifications to the node in a delayed
* fashion. */
int tn_status;
#define TMPFS_NODE_ACCESSED (1 << 1)
#define TMPFS_NODE_MODIFIED (1 << 2)
#define TMPFS_NODE_CHANGED (1 << 3)
/* The node size. It does not necessarily match the real amount
* of memory consumed by it. */
off_t tn_size;
/* Generic node attributes. */
uid_t tn_uid;
gid_t tn_gid;
mode_t tn_mode;
int tn_flags;
nlink_t tn_links;
struct timespec tn_atime;
struct timespec tn_mtime;
struct timespec tn_ctime;
struct timespec tn_birthtime;
unsigned long tn_gen;
/* Head of byte-level lock list (used by tmpfs_advlock). */
struct lockf * tn_lockf;
/* 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;
/* Pointer to the node returned by tmpfs_lookup() after doing a
* delete or a rename lookup; its value is only valid in these two
* situations. In case we were looking up . or .., it holds a null
* pointer. */
struct tmpfs_dirent * tn_lookup_dirent;
/* interlock to protect tn_vpstate */
struct mtx tn_interlock;
/* Identify if current node has vnode assiocate with
* or allocating vnode.
*/
int tn_vpstate;
/* misc data field for different tn_type node */
union {
/* Valid when tn_type == VBLK || tn_type == VCHR. */
dev_t tn_rdev;
/* 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 tail-queue that links the contents of
* the directory together. See above for a
* description of its contents. */
struct tmpfs_dir tn_dirhead;
/* 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 and a linear
* scan is performed from the beginning up to the
* point where readdir starts returning values. */
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. */
char * 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,
* because its contents are always mapped in a
* contiguous region of virtual memory. It is a task
* of the memory management subsystem (see uvm(9)) to
* issue the required page ins or page outs whenever
* a position within the file is accessed. */
vm_object_t tn_aobj;
size_t tn_aobj_pages;
}tn_reg;
/* Valid when tn_type = VFIFO */
struct tn_fifo {
fo_rdwr_t *tn_fo_read;
fo_rdwr_t *tn_fo_write;
}tn_fifo;
}tn_spec;
};
LIST_HEAD(tmpfs_node_list, tmpfs_node);
#define tn_rdev tn_spec.tn_rdev
#define tn_dir tn_spec.tn_dir
#define tn_link tn_spec.tn_link
#define tn_reg tn_spec.tn_reg
#define tn_fifo tn_spec.tn_fifo
#define TMPFS_NODE_LOCK(node) mtx_lock(&(node)->tn_interlock)
#define TMPFS_NODE_UNLOCK(node) mtx_unlock(&(node)->tn_interlock)
#define TMPFS_VNODE_ALLOCATING 1
#define TMPFS_VNODE_WANT 2
/* --------------------------------------------------------------------- */
/*
* Internal representation of a tmpfs mount point.
*/
struct tmpfs_mount {
/* 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 that the current amount of
* free memory; in the extreme case, it will hold the SIZE_MAX
* value. Instead, use the TMPFS_PAGES_MAX macro. */
size_t tm_pages_max;
/* Number of pages in use by the file system. Cannot be bigger
* than the value returned by TMPFS_PAGES_MAX in any case. */
size_t 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;
/* Number of nodes currently allocated. This number only grows.
* When it reaches tm_nodes_max, no more new nodes can be allocated.
* Of course, the old, unused ones can be reused. */
ino_t tm_nodes_last;
/* Number of nodes currently that are in use. */
ino_t tm_nodes_inuse;
/* maximum representable file size */
u_int64_t tm_maxfilesize;
/* Nodes are organized in two different lists. The used list
* contains all nodes that are currently used by the file system;
* i.e., they refer to existing files. The available list contains
* all nodes that are currently available for use by new files.
* Nodes must be kept in this list (instead of deleting them)
* because we need to keep track of their generation number (tn_gen
* field).
*
* Note that nodes are lazily allocated: if the available list is
* empty and we have enough space to create more nodes, they will be
* created and inserted in the used list. Once these are released,
* they will go into the available list, remaining alive until the
* file system is unmounted. */
struct tmpfs_node_list tm_nodes_used;
/* All node lock to protect the node list and tmp_pages_used */
struct mtx allnode_lock;
/* Pools used to store file system meta data. These are not shared
* across several instances of tmpfs for the reasons described in
* tmpfs_pool.c. */
uma_zone_t tm_dirent_pool;
uma_zone_t tm_node_pool;
struct tmpfs_str_zone tm_str_pool;
};
#define TMPFS_LOCK(tm) mtx_lock(&(tm)->allnode_lock)
#define TMPFS_UNLOCK(tm) mtx_unlock(&(tm)->allnode_lock)
/* --------------------------------------------------------------------- */
/*
* This structure maps a file identifier to a tmpfs node. Used by the
* NFS code.
*/
struct tmpfs_fid {
uint16_t tf_len;
uint16_t tf_pad;
unsigned long tf_gen;
ino_t tf_id;
};
/* --------------------------------------------------------------------- */
#ifdef _KERNEL
/*
* Prototypes for tmpfs_subr.c.
*/
int tmpfs_alloc_node(struct tmpfs_mount *, enum vtype,
uid_t uid, gid_t gid, mode_t mode, struct tmpfs_node *,
char *, dev_t, struct thread *, struct tmpfs_node **);
void tmpfs_free_node(struct tmpfs_mount *, struct tmpfs_node *);
int tmpfs_alloc_dirent(struct tmpfs_mount *, struct tmpfs_node *,
const char *, uint16_t, struct tmpfs_dirent **);
void tmpfs_free_dirent(struct tmpfs_mount *, struct tmpfs_dirent *,
boolean_t);
int tmpfs_alloc_vp(struct mount *, struct tmpfs_node *, struct vnode **,
struct thread *td);
void tmpfs_free_vp(struct vnode *);
int tmpfs_alloc_file(struct vnode *, struct vnode **, struct vattr *,
struct componentname *, char *);
void tmpfs_dir_attach(struct vnode *, struct tmpfs_dirent *);
void tmpfs_dir_detach(struct vnode *, struct tmpfs_dirent *);
struct tmpfs_dirent * tmpfs_dir_lookup(struct tmpfs_node *node,
struct componentname *cnp);
int tmpfs_dir_getdotdent(struct tmpfs_node *, struct uio *);
int tmpfs_dir_getdotdotdent(struct tmpfs_node *, struct uio *);
struct tmpfs_dirent * tmpfs_dir_lookupbycookie(struct tmpfs_node *, off_t);
int tmpfs_dir_getdents(struct tmpfs_node *, struct uio *, off_t *);
int tmpfs_reg_resize(struct vnode *, off_t);
int tmpfs_chflags(struct vnode *, int, 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 timespec *, struct timespec *,
struct timespec *, int, struct ucred *, struct thread *);
void tmpfs_itimes(struct vnode *, const struct timespec *,
const struct timespec *);
void tmpfs_update(struct vnode *);
int tmpfs_truncate(struct vnode *, off_t);
/* --------------------------------------------------------------------- */
/*
* Convenience macros to simplify some logical expressions.
*/
#define IMPLIES(a, b) (!(a) || (b))
#define IFF(a, b) (IMPLIES(a, b) && IMPLIES(b, a))
/* --------------------------------------------------------------------- */
/*
* 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 == (uint16_t)len && \
memcmp((de)->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) \
MPASS((node)->tn_type == VDIR); \
MPASS((node)->tn_size % sizeof(struct tmpfs_dirent) == 0); \
MPASS((node)->tn_dir.tn_readdir_lastp == NULL || \
TMPFS_DIRCOOKIE((node)->tn_dir.tn_readdir_lastp) == (node)->tn_dir.tn_readdir_lastn);
/* --------------------------------------------------------------------- */
/*
* Memory management stuff.
*/
/* Amount of memory pages to reserve for the system (e.g., to not use by
* tmpfs).
* XXX: Should this be tunable through sysctl, for instance? */
#define TMPFS_PAGES_RESERVED (4 * 1024 * 1024 / PAGE_SIZE)
/*
* Returns information about the number of available memory pages,
* including physical and virtual ones.
*
* If 'total' is TRUE, the value returned is the total amount of memory
* pages configured for the system (either in use or free).
* If it is FALSE, the value returned is the amount of free memory pages.
*
* Remember to remove TMPFS_PAGES_RESERVED from the returned value to avoid
* excessive memory usage.
*
*/
static __inline size_t
tmpfs_mem_info(void)
{
size_t size;
size = swap_pager_avail + cnt.v_free_count + cnt.v_inactive_count;
size -= size > cnt.v_wire_count ? cnt.v_wire_count : size;
return size;
}
/* Returns the maximum size allowed for a tmpfs file system. This macro
* must be used instead of directly retrieving the value from tm_pages_max.
* The reason is that the size of a tmpfs file system is dynamic: it lets
* the user store files as long as there is enough free memory (including
* physical memory and swap space). Therefore, the amount of memory to be
* used is either the limit imposed by the user during mount time or the
* amount of available memory, whichever is lower. To avoid consuming all
* the memory for a given mount point, the system will always reserve a
* minimum of TMPFS_PAGES_RESERVED pages, which is also taken into account
* by this macro (see above). */
static __inline size_t
TMPFS_PAGES_MAX(struct tmpfs_mount *tmp)
{
size_t freepages;
freepages = tmpfs_mem_info();
freepages -= freepages < TMPFS_PAGES_RESERVED ?
freepages : TMPFS_PAGES_RESERVED;
return MIN(tmp->tm_pages_max, freepages + tmp->tm_pages_used);
}
/* Returns the available space for the given file system. */
MFp4: Several clean-ups and improvements over tmpfs: - Remove tmpfs_zone_xxx KPI, the uma(9) wrapper, since they does not bring any value now. - Use |= instead of = when applying VV_ROOT flag. - Remove tm_avariable_nodes list. Use uma to hold the released nodes. - init/destory interlock mutex of node when init/fini instead of ctor/dtor. - Change memory computing using u_int to fix negative value in 2G mem machine. - Remove unnecessary bzero's - Rely uma logic to make file id allocation harder to guess. - Fix some unsigned/signed related things. Make sure we respect -o size=xxxx - Use wire instead of hold a page. - Pass allocate_zero to obtain zeroed pages upon first use. Submitted by: Howard Su Approved by: re (tmpfs blanket, kensmith)
2007-06-25 18:46:13 +00:00
#define TMPFS_META_PAGES(tmp) ((tmp)->tm_nodes_inuse * (sizeof(struct tmpfs_node) \
+ sizeof(struct tmpfs_dirent))/PAGE_SIZE + 1)
#define TMPFS_FILE_PAGES(tmp) ((tmp)->tm_pages_used)
#define TMPFS_PAGES_AVAIL(tmp) (TMPFS_PAGES_MAX(tmp) > \
TMPFS_META_PAGES(tmp)+TMPFS_FILE_PAGES(tmp)? \
TMPFS_PAGES_MAX(tmp) - TMPFS_META_PAGES(tmp) \
- TMPFS_FILE_PAGES(tmp):0)
MFp4: Add tmpfs, an efficient memory file system. Please note that, this is currently considered as an experimental feature so there could be some rough edges. Consult http://wiki.freebsd.org/TMPFS for more information. For now, connect tmpfs to build on i386 and amd64 architectures only. Please let us know if you have success with other platforms. This work was developed by Julio M. Merino Vidal for NetBSD as a SoC project; Rohit Jalan ported it from NetBSD to FreeBSD. Howard Su and Glen Leeder are worked on it to continue this effort. Obtained from: NetBSD via p4 Submitted by: Howard Su (with some minor changes) Approved by: re (kensmith)
2007-06-16 01:56:05 +00:00
#endif
/* --------------------------------------------------------------------- */
/*
* Macros/functions to convert from generic data structures to tmpfs
* specific ones.
*/
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;
}
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;
}
/* ---------------------------------------------------------------------
* USER AND KERNEL DEFINITIONS
* --------------------------------------------------------------------- */
/*
* This structure is used to communicate mount parameters between userland
* and kernel space.
*/
#define TMPFS_ARGS_VERSION 1
struct tmpfs_args {
int ta_version;
/* Size counters. */
ino_t ta_nodes_max;
off_t ta_size_max;
/* Root node attributes. */
uid_t ta_root_uid;
gid_t ta_root_gid;
mode_t ta_root_mode;
};
#endif /* _FS_TMPFS_TMPFS_H_ */
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