/* $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. */ #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_uint8(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; /* * Total size of whiteout directory entries. This * must be a multiple of sizeof(struct tmpfs_dirent) * and is used to determine whether a directory is * empty (excluding whiteout entries) during rename/ * rmdir operations. */ off_t tn_wht_size; /* (v) */ } 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; /* Read from page cache directly. */ bool tm_pgread; }; #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 { unsigned short tfd_len; ino_t tfd_id; unsigned long tfd_gen; } __packed; 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_uint8(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 *); void tmpfs_dir_clear_whiteouts(struct vnode *); 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); \ MPASS((node)->tn_dir.tn_wht_size % sizeof(struct tmpfs_dirent) == 0); \ MPASS((node)->tn_dir.tn_wht_size <= (node)->tn_size); \ } 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 /* * Percent of available memory + swap available to use by tmpfs file systems * without a size limit. */ #if !defined(TMPFS_MEM_PERCENT) #define TMPFS_MEM_PERCENT 100 #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_ */
