Date: Mon, 27 Sep 2010 17:47:10 +0000 (UTC) From: Jaakko Heinonen <jh@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r213215 - in head/sys: conf fs/devfs Message-ID: <201009271747.o8RHlATi044368@svn.freebsd.org>
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Author: jh Date: Mon Sep 27 17:47:09 2010 New Revision: 213215 URL: http://svn.freebsd.org/changeset/base/213215 Log: Add reference counting for devfs paths containing user created symbolic links. The reference counting is needed to be able to determine if a specific devfs path exists. For true device file paths we can traverse the cdevp_list but a separate directory list is needed for user created symbolic links. Add a new directory entry flag DE_USER to mark entries which should unreference their parent directory on deletion. A new function to traverse cdevp_list and the directory list will be introduced in a separate commit. Idea from: kib Reviewed by: kib Added: head/sys/fs/devfs/devfs_dir.c (contents, props changed) Modified: head/sys/conf/files head/sys/fs/devfs/devfs.h head/sys/fs/devfs/devfs_devs.c head/sys/fs/devfs/devfs_int.h head/sys/fs/devfs/devfs_vnops.c Modified: head/sys/conf/files ============================================================================== --- head/sys/conf/files Mon Sep 27 17:46:11 2010 (r213214) +++ head/sys/conf/files Mon Sep 27 17:47:09 2010 (r213215) @@ -1890,6 +1890,7 @@ fs/coda/coda_vfsops.c optional vcoda fs/coda/coda_vnops.c optional vcoda fs/deadfs/dead_vnops.c standard fs/devfs/devfs_devs.c standard +fs/devfs/devfs_dir.c standard fs/devfs/devfs_rule.c standard fs/devfs/devfs_vfsops.c standard fs/devfs/devfs_vnops.c standard Modified: head/sys/fs/devfs/devfs.h ============================================================================== --- head/sys/fs/devfs/devfs.h Mon Sep 27 17:46:11 2010 (r213214) +++ head/sys/fs/devfs/devfs.h Mon Sep 27 17:47:09 2010 (r213215) @@ -124,6 +124,8 @@ MALLOC_DECLARE(M_DEVFS); struct componentname; +TAILQ_HEAD(devfs_dlist_head, devfs_dirent); + struct devfs_dirent { struct cdev_priv *de_cdp; int de_inode; @@ -133,10 +135,11 @@ struct devfs_dirent { #define DE_DOTDOT 0x04 #define DE_DOOMED 0x08 #define DE_COVERED 0x10 +#define DE_USER 0x20 int de_holdcnt; struct dirent *de_dirent; TAILQ_ENTRY(devfs_dirent) de_list; - TAILQ_HEAD(, devfs_dirent) de_dlist; + struct devfs_dlist_head de_dlist; struct devfs_dirent *de_dir; int de_links; mode_t de_mode; Modified: head/sys/fs/devfs/devfs_devs.c ============================================================================== --- head/sys/fs/devfs/devfs_devs.c Mon Sep 27 17:46:11 2010 (r213214) +++ head/sys/fs/devfs/devfs_devs.c Mon Sep 27 17:47:09 2010 (r213215) @@ -338,6 +338,10 @@ devfs_delete(struct devfs_mount *dm, str dd = devfs_parent_dirent(de); if (dd != NULL) DEVFS_DE_HOLD(dd); + if (de->de_flags & DE_USER) { + KASSERT(dd != NULL, ("devfs_delete: NULL dd")); + devfs_dir_unref_de(dm, dd); + } } else dd = NULL; @@ -396,10 +400,17 @@ devfs_purge(struct devfs_mount *dm, stru DEVFS_DE_HOLD(dd); for (;;) { - de = TAILQ_FIRST(&dd->de_dlist); + /* + * Use TAILQ_LAST() to remove "." and ".." last. + * We might need ".." to resolve a path in + * devfs_dir_unref_de(). + */ + de = TAILQ_LAST(&dd->de_dlist, devfs_dlist_head); if (de == NULL) break; TAILQ_REMOVE(&dd->de_dlist, de, de_list); + if (de->de_flags & DE_USER) + devfs_dir_unref_de(dm, dd); if (de->de_flags & (DE_DOT | DE_DOTDOT)) devfs_delete(dm, de, DEVFS_DEL_NORECURSE); else if (de->de_dirent->d_type == DT_DIR) Added: head/sys/fs/devfs/devfs_dir.c ============================================================================== --- /dev/null 00:00:00 1970 (empty, because file is newly added) +++ head/sys/fs/devfs/devfs_dir.c Mon Sep 27 17:47:09 2010 (r213215) @@ -0,0 +1,175 @@ +/*- + * Copyright (c) 2010 Jaakko Heinonen <jh@FreeBSD.org> + * All rights reserved. + * + * 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 AUTHOR 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 AUTHOR 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. + * + * $FreeBSD$ + */ + +#include <sys/param.h> +#include <sys/conf.h> +#include <sys/types.h> +#include <sys/kernel.h> +#include <sys/libkern.h> +#include <sys/lock.h> +#include <sys/malloc.h> +#include <sys/mutex.h> +#include <sys/queue.h> +#include <sys/systm.h> +#include <sys/sx.h> + +#include <fs/devfs/devfs.h> +#include <fs/devfs/devfs_int.h> + +struct dirlistent { + char *dir; + int refcnt; + LIST_ENTRY(dirlistent) link; +}; + +static LIST_HEAD(, dirlistent) devfs_dirlist = + LIST_HEAD_INITIALIZER(devfs_dirlist); + +static MALLOC_DEFINE(M_DEVFS4, "DEVFS4", "DEVFS directory list"); + +static struct mtx dirlist_mtx; +MTX_SYSINIT(dirlist_mtx, &dirlist_mtx, "devfs dirlist lock", MTX_DEF); + +/* Returns 1 if the path is in the directory list. */ +int +devfs_dir_find(const char *path) +{ + struct dirlistent *dle; + + mtx_lock(&dirlist_mtx); + LIST_FOREACH(dle, &devfs_dirlist, link) { + if (devfs_pathpath(dle->dir, path) != 0) { + mtx_unlock(&dirlist_mtx); + return (1); + } + } + mtx_unlock(&dirlist_mtx); + + return (0); +} + +static struct dirlistent * +devfs_dir_findent_locked(const char *dir) +{ + struct dirlistent *dle; + + mtx_assert(&dirlist_mtx, MA_OWNED); + + LIST_FOREACH(dle, &devfs_dirlist, link) { + if (strcmp(dir, dle->dir) == 0) + return (dle); + } + + return (NULL); +} + +static void +devfs_dir_ref(const char *dir) +{ + struct dirlistent *dle, *dle_new; + + if (*dir == '\0') + return; + + dle_new = malloc(sizeof(*dle), M_DEVFS4, M_WAITOK); + dle_new->dir = strdup(dir, M_DEVFS4); + dle_new->refcnt = 1; + + mtx_lock(&dirlist_mtx); + dle = devfs_dir_findent_locked(dir); + if (dle != NULL) { + dle->refcnt++; + mtx_unlock(&dirlist_mtx); + free(dle_new->dir, M_DEVFS4); + free(dle_new, M_DEVFS4); + return; + } + LIST_INSERT_HEAD(&devfs_dirlist, dle_new, link); + mtx_unlock(&dirlist_mtx); +} + +void +devfs_dir_ref_de(struct devfs_mount *dm, struct devfs_dirent *de) +{ + char dirname[SPECNAMELEN + 1], *namep; + + namep = devfs_fqpn(dirname, dm, de, NULL); + KASSERT(namep != NULL, ("devfs_ref_dir_de: NULL namep")); + + devfs_dir_ref(namep); +} + +static void +devfs_dir_unref(const char *dir) +{ + struct dirlistent *dle; + + if (*dir == '\0') + return; + + mtx_lock(&dirlist_mtx); + dle = devfs_dir_findent_locked(dir); + KASSERT(dle != NULL, ("devfs_dir_unref: dir %s not referenced", dir)); + dle->refcnt--; + KASSERT(dle->refcnt >= 0, ("devfs_dir_unref: negative refcnt")); + if (dle->refcnt == 0) { + LIST_REMOVE(dle, link); + mtx_unlock(&dirlist_mtx); + free(dle->dir, M_DEVFS4); + free(dle, M_DEVFS4); + } else + mtx_unlock(&dirlist_mtx); +} + +void +devfs_dir_unref_de(struct devfs_mount *dm, struct devfs_dirent *de) +{ + char dirname[SPECNAMELEN + 1], *namep; + + namep = devfs_fqpn(dirname, dm, de, NULL); + KASSERT(namep != NULL, ("devfs_unref_dir_de: NULL namep")); + + devfs_dir_unref(namep); +} + +/* Returns 1 if the path p1 contains the path p2. */ +int +devfs_pathpath(const char *p1, const char *p2) +{ + + for (;;p1++, p2++) { + if (*p1 != *p2) { + if (*p1 == '/' && *p2 == '\0') + return (1); + else + return (0); + } else if (*p1 == '\0') + return (1); + } + /* NOTREACHED */ +} Modified: head/sys/fs/devfs/devfs_int.h ============================================================================== --- head/sys/fs/devfs/devfs_int.h Mon Sep 27 17:46:11 2010 (r213214) +++ head/sys/fs/devfs/devfs_int.h Mon Sep 27 17:47:09 2010 (r213215) @@ -38,6 +38,7 @@ #ifdef _KERNEL struct devfs_dirent; +struct devfs_mount; struct cdev_privdata { struct file *cdpd_fp; @@ -76,6 +77,11 @@ void devfs_create(struct cdev *dev); void devfs_destroy(struct cdev *dev); void devfs_destroy_cdevpriv(struct cdev_privdata *p); +int devfs_dir_find(const char *); +void devfs_dir_ref_de(struct devfs_mount *, struct devfs_dirent *); +void devfs_dir_unref_de(struct devfs_mount *, struct devfs_dirent *); +int devfs_pathpath(const char *, const char *); + extern struct unrhdr *devfs_inos; extern struct mtx devmtx; extern struct mtx devfs_de_interlock; Modified: head/sys/fs/devfs/devfs_vnops.c ============================================================================== --- head/sys/fs/devfs/devfs_vnops.c Mon Sep 27 17:46:11 2010 (r213214) +++ head/sys/fs/devfs/devfs_vnops.c Mon Sep 27 17:47:09 2010 (r213215) @@ -1564,6 +1564,7 @@ devfs_symlink(struct vop_symlink_args *a dd = ap->a_dvp->v_data; de = devfs_newdirent(ap->a_cnp->cn_nameptr, ap->a_cnp->cn_namelen); + de->de_flags = DE_USER; de->de_uid = 0; de->de_gid = 0; de->de_mode = 0755; @@ -1587,6 +1588,7 @@ devfs_symlink(struct vop_symlink_args *a de_dotdot = TAILQ_FIRST(&dd->de_dlist); /* "." */ de_dotdot = TAILQ_NEXT(de_dotdot, de_list); /* ".." */ TAILQ_INSERT_AFTER(&dd->de_dlist, de_dotdot, de, de_list); + devfs_dir_ref_de(dmp, dd); return (devfs_allocv(de, ap->a_dvp->v_mount, LK_EXCLUSIVE, ap->a_vpp)); }
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