/* $NetBSD: tmpfs_vfsops.c,v 1.10 2005/12/11 12:24:29 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. * * 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. */ /* * Efficient memory file system. * * tmpfs is a file system that uses NetBSD's virtual memory sub-system * (the well-known UVM) to store file data and metadata in an efficient * way. This means that it does not follow the structure of an on-disk * file system because it simply does not need to. Instead, it uses * memory-specific data structures and algorithms to automatically * allocate and release resources. */ #include __FBSDID("$FreeBSD$"); #include #include #include #include #include #include #include #include #include #include #include #include /* * Default permission for root node */ #define TMPFS_DEFAULT_ROOT_MODE (S_IRWXU|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH) MALLOC_DEFINE(M_TMPFSMNT, "tmpfs mount", "tmpfs mount structures"); MALLOC_DEFINE(M_TMPFSNAME, "tmpfs name", "tmpfs file names"); /* --------------------------------------------------------------------- */ static int tmpfs_mount(struct mount *); static int tmpfs_unmount(struct mount *, int); static int tmpfs_root(struct mount *, int flags, struct vnode **); static int tmpfs_fhtovp(struct mount *, struct fid *, int, struct vnode **); static int tmpfs_statfs(struct mount *, struct statfs *); /* --------------------------------------------------------------------- */ static const char *tmpfs_opts[] = { "from", "size", "maxfilesize", "inodes", "uid", "gid", "mode", "export", NULL }; static const char *tmpfs_updateopts[] = { "from", "export", NULL }; /* --------------------------------------------------------------------- */ static int tmpfs_node_ctor(void *mem, int size, void *arg, int flags) { struct tmpfs_node *node = (struct tmpfs_node *)mem; node->tn_gen++; node->tn_size = 0; node->tn_status = 0; node->tn_flags = 0; node->tn_links = 0; node->tn_vnode = NULL; node->tn_vpstate = 0; return (0); } static void tmpfs_node_dtor(void *mem, int size, void *arg) { struct tmpfs_node *node = (struct tmpfs_node *)mem; node->tn_type = VNON; } static int tmpfs_node_init(void *mem, int size, int flags) { struct tmpfs_node *node = (struct tmpfs_node *)mem; node->tn_id = 0; mtx_init(&node->tn_interlock, "tmpfs node interlock", NULL, MTX_DEF); node->tn_gen = arc4random(); return (0); } static void tmpfs_node_fini(void *mem, int size) { struct tmpfs_node *node = (struct tmpfs_node *)mem; mtx_destroy(&node->tn_interlock); } static int tmpfs_mount(struct mount *mp) { const size_t nodes_per_page = howmany(PAGE_SIZE, sizeof(struct tmpfs_dirent) + sizeof(struct tmpfs_node)); struct tmpfs_mount *tmp; struct tmpfs_node *root; int error; /* Size counters. */ u_quad_t pages; off_t nodes_max, size_max, maxfilesize; /* Root node attributes. */ uid_t root_uid; gid_t root_gid; mode_t root_mode; struct vattr va; if (vfs_filteropt(mp->mnt_optnew, tmpfs_opts)) return (EINVAL); if (mp->mnt_flag & MNT_UPDATE) { /* Only support update mounts for certain options. */ if (vfs_filteropt(mp->mnt_optnew, tmpfs_updateopts) != 0) return (EOPNOTSUPP); if (vfs_flagopt(mp->mnt_optnew, "ro", NULL, 0) != ((struct tmpfs_mount *)mp->mnt_data)->tm_ronly) return (EOPNOTSUPP); return (0); } vn_lock(mp->mnt_vnodecovered, LK_SHARED | LK_RETRY); error = VOP_GETATTR(mp->mnt_vnodecovered, &va, mp->mnt_cred); VOP_UNLOCK(mp->mnt_vnodecovered, 0); if (error) return (error); if (mp->mnt_cred->cr_ruid != 0 || vfs_scanopt(mp->mnt_optnew, "gid", "%d", &root_gid) != 1) root_gid = va.va_gid; if (mp->mnt_cred->cr_ruid != 0 || vfs_scanopt(mp->mnt_optnew, "uid", "%d", &root_uid) != 1) root_uid = va.va_uid; if (mp->mnt_cred->cr_ruid != 0 || vfs_scanopt(mp->mnt_optnew, "mode", "%ho", &root_mode) != 1) root_mode = va.va_mode; if (vfs_getopt_size(mp->mnt_optnew, "inodes", &nodes_max) != 0) nodes_max = 0; if (vfs_getopt_size(mp->mnt_optnew, "size", &size_max) != 0) size_max = 0; if (vfs_getopt_size(mp->mnt_optnew, "maxfilesize", &maxfilesize) != 0) maxfilesize = 0; /* Do not allow mounts if we do not have enough memory to preserve * the minimum reserved pages. */ if (tmpfs_mem_avail() < TMPFS_PAGES_MINRESERVED) return ENOSPC; /* Get the maximum number of memory pages this file system is * allowed to use, based on the maximum size the user passed in * the mount structure. A value of zero is treated as if the * maximum available space was requested. */ if (size_max < PAGE_SIZE || size_max > OFF_MAX - PAGE_SIZE || (SIZE_MAX < OFF_MAX && size_max / PAGE_SIZE >= SIZE_MAX)) pages = SIZE_MAX; else pages = howmany(size_max, PAGE_SIZE); MPASS(pages > 0); if (nodes_max <= 3) { if (pages < INT_MAX / nodes_per_page) nodes_max = pages * nodes_per_page; else nodes_max = INT_MAX; } if (nodes_max > INT_MAX) nodes_max = INT_MAX; MPASS(nodes_max >= 3); /* Allocate the tmpfs mount structure and fill it. */ tmp = (struct tmpfs_mount *)malloc(sizeof(struct tmpfs_mount), M_TMPFSMNT, M_WAITOK | M_ZERO); mtx_init(&tmp->allnode_lock, "tmpfs allnode lock", NULL, MTX_DEF); tmp->tm_nodes_max = nodes_max; tmp->tm_nodes_inuse = 0; tmp->tm_maxfilesize = maxfilesize > 0 ? maxfilesize : OFF_MAX; LIST_INIT(&tmp->tm_nodes_used); tmp->tm_pages_max = pages; tmp->tm_pages_used = 0; tmp->tm_ino_unr = new_unrhdr(2, INT_MAX, &tmp->allnode_lock); tmp->tm_dirent_pool = uma_zcreate("TMPFS dirent", sizeof(struct tmpfs_dirent), NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0); tmp->tm_node_pool = uma_zcreate("TMPFS node", sizeof(struct tmpfs_node), tmpfs_node_ctor, tmpfs_node_dtor, tmpfs_node_init, tmpfs_node_fini, UMA_ALIGN_PTR, 0); tmp->tm_ronly = (mp->mnt_flag & MNT_RDONLY) != 0; /* Allocate the root node. */ error = tmpfs_alloc_node(tmp, VDIR, root_uid, root_gid, root_mode & ALLPERMS, NULL, NULL, VNOVAL, &root); if (error != 0 || root == NULL) { uma_zdestroy(tmp->tm_node_pool); uma_zdestroy(tmp->tm_dirent_pool); delete_unrhdr(tmp->tm_ino_unr); free(tmp, M_TMPFSMNT); return error; } KASSERT(root->tn_id == 2, ("tmpfs root with invalid ino: %d", root->tn_id)); tmp->tm_root = root; MNT_ILOCK(mp); mp->mnt_flag |= MNT_LOCAL; mp->mnt_kern_flag |= MNTK_MPSAFE; MNT_IUNLOCK(mp); mp->mnt_data = tmp; mp->mnt_stat.f_namemax = MAXNAMLEN; vfs_getnewfsid(mp); vfs_mountedfrom(mp, "tmpfs"); return 0; } /* --------------------------------------------------------------------- */ /* ARGSUSED2 */ static int tmpfs_unmount(struct mount *mp, int mntflags) { int error; int flags = 0; struct tmpfs_mount *tmp; struct tmpfs_node *node; /* Handle forced unmounts. */ if (mntflags & MNT_FORCE) flags |= FORCECLOSE; /* Finalize all pending I/O. */ error = vflush(mp, 0, flags, curthread); if (error != 0) return error; tmp = VFS_TO_TMPFS(mp); /* Free all associated data. The loop iterates over the linked list * we have containing all used nodes. For each of them that is * a directory, we free all its directory entries. Note that after * freeing a node, it will automatically go to the available list, * so we will later have to iterate over it to release its items. */ node = LIST_FIRST(&tmp->tm_nodes_used); while (node != NULL) { struct tmpfs_node *next; if (node->tn_type == VDIR) { struct tmpfs_dirent *de; de = TAILQ_FIRST(&node->tn_dir.tn_dirhead); while (de != NULL) { struct tmpfs_dirent *nde; nde = TAILQ_NEXT(de, td_entries); tmpfs_free_dirent(tmp, de, FALSE); de = nde; node->tn_size -= sizeof(struct tmpfs_dirent); } } next = LIST_NEXT(node, tn_entries); tmpfs_free_node(tmp, node); node = next; } uma_zdestroy(tmp->tm_dirent_pool); uma_zdestroy(tmp->tm_node_pool); delete_unrhdr(tmp->tm_ino_unr); mtx_destroy(&tmp->allnode_lock); MPASS(tmp->tm_pages_used == 0); MPASS(tmp->tm_nodes_inuse == 0); /* Throw away the tmpfs_mount structure. */ free(mp->mnt_data, M_TMPFSMNT); mp->mnt_data = NULL; MNT_ILOCK(mp); mp->mnt_flag &= ~MNT_LOCAL; MNT_IUNLOCK(mp); return 0; } /* --------------------------------------------------------------------- */ static int tmpfs_root(struct mount *mp, int flags, struct vnode **vpp) { int error; error = tmpfs_alloc_vp(mp, VFS_TO_TMPFS(mp)->tm_root, flags, vpp); if (!error) (*vpp)->v_vflag |= VV_ROOT; return error; } /* --------------------------------------------------------------------- */ static int tmpfs_fhtovp(struct mount *mp, struct fid *fhp, int flags, struct vnode **vpp) { boolean_t found; struct tmpfs_fid *tfhp; struct tmpfs_mount *tmp; struct tmpfs_node *node; tmp = VFS_TO_TMPFS(mp); tfhp = (struct tmpfs_fid *)fhp; if (tfhp->tf_len != sizeof(struct tmpfs_fid)) return EINVAL; if (tfhp->tf_id >= tmp->tm_nodes_max) return EINVAL; found = FALSE; TMPFS_LOCK(tmp); LIST_FOREACH(node, &tmp->tm_nodes_used, tn_entries) { if (node->tn_id == tfhp->tf_id && node->tn_gen == tfhp->tf_gen) { found = TRUE; break; } } TMPFS_UNLOCK(tmp); if (found) return (tmpfs_alloc_vp(mp, node, LK_EXCLUSIVE, vpp)); return (EINVAL); } /* --------------------------------------------------------------------- */ /* ARGSUSED2 */ static int tmpfs_statfs(struct mount *mp, struct statfs *sbp) { struct tmpfs_mount *tmp; size_t used; tmp = VFS_TO_TMPFS(mp); sbp->f_iosize = PAGE_SIZE; sbp->f_bsize = PAGE_SIZE; used = tmpfs_pages_used(tmp); if (tmp->tm_pages_max != SIZE_MAX) sbp->f_blocks = tmp->tm_pages_max; else sbp->f_blocks = used + tmpfs_mem_avail(); if (sbp->f_blocks <= used) sbp->f_bavail = 0; else sbp->f_bavail = sbp->f_blocks - used; sbp->f_bfree = sbp->f_bavail; used = tmp->tm_nodes_inuse; sbp->f_files = tmp->tm_nodes_max; if (sbp->f_files <= used) sbp->f_ffree = 0; else sbp->f_ffree = sbp->f_files - used; /* sbp->f_owner = tmp->tn_uid; */ return 0; } /* --------------------------------------------------------------------- */ /* * tmpfs vfs operations. */ struct vfsops tmpfs_vfsops = { .vfs_mount = tmpfs_mount, .vfs_unmount = tmpfs_unmount, .vfs_root = tmpfs_root, .vfs_statfs = tmpfs_statfs, .vfs_fhtovp = tmpfs_fhtovp, }; VFS_SET(tmpfs_vfsops, tmpfs, 0);