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Diffstat (limited to 'sys/fs/tmpfs/tmpfs.h')
| -rw-r--r-- | sys/fs/tmpfs/tmpfs.h | 535 |
1 files changed, 535 insertions, 0 deletions
diff --git a/sys/fs/tmpfs/tmpfs.h b/sys/fs/tmpfs/tmpfs.h new file mode 100644 index 000000000000..87239d405dd5 --- /dev/null +++ b/sys/fs/tmpfs/tmpfs.h @@ -0,0 +1,535 @@ +/* $NetBSD: tmpfs.h,v 1.26 2007/02/22 06:37:00 thorpej Exp $ */ + +/*- + * SPDX-License-Identifier: BSD-2-Clause-NetBSD + * + * 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/queue.h> +#include <sys/tree.h> + +#ifdef _SYS_MALLOC_H_ +MALLOC_DECLARE(M_TMPFSMNT); +MALLOC_DECLARE(M_TMPFSNAME); +#endif + +/* + * 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 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 + */ +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) */ + bool tn_attached; /* (m) */ + + /* + * 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) */ + + /* Node identifier. */ + ino_t tn_id; /* (c) */ + + /* + * 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; /* (vi) */ +#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; /* (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; /* (m) + (i) */ + + /* 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. */ + char * tn_link; /* (c) */ + + /* 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) */ + } 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 tn_spec.tn_link +#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 + +#define TMPFS_VNODE_ALLOCATING 1 +#define TMPFS_VNODE_WANT 2 +#define TMPFS_VNODE_DOOMED 4 +#define TMPFS_VNODE_WRECLAIM 8 + +/* + * 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 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; + + /* 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; + + /* Zones used to store file system meta data, per tmpfs mount. */ + uma_zone_t tm_dirent_pool; + uma_zone_t tm_node_pool; + + /* Read-only status. */ + bool tm_ronly; + /* Do not use namecache. */ + bool tm_nonc; +}; +#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 { + uint16_t tf_len; + uint16_t tf_pad; + ino_t tf_id; + unsigned long tf_gen; +}; + +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); +void tmpfs_ref_node_locked(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 **); +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_node *, struct uio *, int, + u_long *, 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_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_status(struct tmpfs_node *node, int status); +void tmpfs_update(struct vnode *); +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); + +/* + * 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 == 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). + */ +#define TMPFS_PAGES_MINRESERVED (4 * 1024 * 1024 / PAGE_SIZE) + +size_t tmpfs_mem_avail(void); + +size_t tmpfs_pages_used(struct tmpfs_mount *tmp); + +#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); +} + +static inline bool +tmpfs_use_nc(struct vnode *vp) +{ + + return (!(VFS_TO_TMPFS(vp->v_mount)->tm_nonc)); +} + +#endif /* _FS_TMPFS_TMPFS_H_ */ |