diff options
Diffstat (limited to 'fs/configfs')
| -rw-r--r-- | fs/configfs/Kconfig | 2 | ||||
| -rw-r--r-- | fs/configfs/Makefile | 1 | ||||
| -rw-r--r-- | fs/configfs/configfs_internal.h | 89 | ||||
| -rw-r--r-- | fs/configfs/dir.c | 942 | ||||
| -rw-r--r-- | fs/configfs/file.c | 546 | ||||
| -rw-r--r-- | fs/configfs/inode.c | 141 | ||||
| -rw-r--r-- | fs/configfs/item.c | 116 | ||||
| -rw-r--r-- | fs/configfs/mount.c | 85 | ||||
| -rw-r--r-- | fs/configfs/symlink.c | 265 |
9 files changed, 1210 insertions, 977 deletions
diff --git a/fs/configfs/Kconfig b/fs/configfs/Kconfig index 9febcdefdfdc..1fcd761fe7be 100644 --- a/fs/configfs/Kconfig +++ b/fs/configfs/Kconfig @@ -1,6 +1,6 @@ +# SPDX-License-Identifier: GPL-2.0-only config CONFIGFS_FS tristate "Userspace-driven configuration filesystem" - select SYSFS help configfs is a RAM-based filesystem that provides the converse of sysfs's functionality. Where sysfs is a filesystem-based diff --git a/fs/configfs/Makefile b/fs/configfs/Makefile index 00ffb278e98c..0200498ede27 100644 --- a/fs/configfs/Makefile +++ b/fs/configfs/Makefile @@ -1,3 +1,4 @@ +# SPDX-License-Identifier: GPL-2.0-only # # Makefile for the configfs virtual filesystem # diff --git a/fs/configfs/configfs_internal.h b/fs/configfs/configfs_internal.h index b5f0a3b91f18..0b969d0eb8ff 100644 --- a/fs/configfs/configfs_internal.h +++ b/fs/configfs/configfs_internal.h @@ -1,39 +1,38 @@ -/* -*- mode: c; c-basic-offset:8; -*- - * vim: noexpandtab sw=8 ts=8 sts=0: - * +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* * configfs_internal.h - Internal stuff for configfs * - * This program is free software; you can redistribute it and/or - * modify it under the terms of the GNU General Public - * License as published by the Free Software Foundation; either - * version 2 of the License, or (at your option) any later version. - * - * This program is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - * General Public License for more details. - * - * You should have received a copy of the GNU General Public - * License along with this program; if not, write to the - * Free Software Foundation, Inc., 59 Temple Place - Suite 330, - * Boston, MA 021110-1307, USA. - * * Based on sysfs: * sysfs is Copyright (C) 2001, 2002, 2003 Patrick Mochel * * configfs Copyright (C) 2005 Oracle. All rights reserved. */ +#ifdef pr_fmt +#undef pr_fmt +#endif + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + #include <linux/slab.h> #include <linux/list.h> #include <linux/spinlock.h> +struct configfs_fragment { + atomic_t frag_count; + struct rw_semaphore frag_sem; + bool frag_dead; +}; + +void put_fragment(struct configfs_fragment *); +struct configfs_fragment *get_fragment(struct configfs_fragment *); + struct configfs_dirent { atomic_t s_count; int s_dependent_count; struct list_head s_sibling; struct list_head s_children; - struct list_head s_links; + int s_links; void * s_element; int s_type; umode_t s_mode; @@ -42,18 +41,22 @@ struct configfs_dirent { #ifdef CONFIG_LOCKDEP int s_depth; #endif + struct configfs_fragment *s_frag; }; #define CONFIGFS_ROOT 0x0001 #define CONFIGFS_DIR 0x0002 #define CONFIGFS_ITEM_ATTR 0x0004 +#define CONFIGFS_ITEM_BIN_ATTR 0x0008 #define CONFIGFS_ITEM_LINK 0x0020 #define CONFIGFS_USET_DIR 0x0040 #define CONFIGFS_USET_DEFAULT 0x0080 #define CONFIGFS_USET_DROPPING 0x0100 #define CONFIGFS_USET_IN_MKDIR 0x0200 #define CONFIGFS_USET_CREATING 0x0400 -#define CONFIGFS_NOT_PINNED (CONFIGFS_ITEM_ATTR) +#define CONFIGFS_NOT_PINNED (CONFIGFS_ITEM_ATTR | CONFIGFS_ITEM_BIN_ATTR) +#define CONFIGFS_PINNED \ + (CONFIGFS_ROOT | CONFIGFS_DIR | CONFIGFS_ITEM_LINK) extern struct mutex configfs_symlink_mutex; extern spinlock_t configfs_dirent_lock; @@ -63,46 +66,38 @@ extern struct kmem_cache *configfs_dir_cachep; extern int configfs_is_root(struct config_item *item); extern struct inode * configfs_new_inode(umode_t mode, struct configfs_dirent *, struct super_block *); -extern int configfs_create(struct dentry *, umode_t mode, int (*init)(struct inode *)); -extern int configfs_inode_init(void); -extern void configfs_inode_exit(void); +extern struct inode *configfs_create(struct dentry *, umode_t mode); extern int configfs_create_file(struct config_item *, const struct configfs_attribute *); -extern int configfs_make_dirent(struct configfs_dirent *, - struct dentry *, void *, umode_t, int); +extern int configfs_create_bin_file(struct config_item *, + const struct configfs_bin_attribute *); +extern int configfs_make_dirent(struct configfs_dirent *, struct dentry *, + void *, umode_t, int, struct configfs_fragment *); extern int configfs_dirent_is_ready(struct configfs_dirent *); -extern int configfs_add_file(struct dentry *, const struct configfs_attribute *, int); -extern void configfs_hash_and_remove(struct dentry * dir, const char * name); - extern const unsigned char * configfs_get_name(struct configfs_dirent *sd); extern void configfs_drop_dentry(struct configfs_dirent *sd, struct dentry *parent); -extern int configfs_setattr(struct dentry *dentry, struct iattr *iattr); +extern int configfs_setattr(struct mnt_idmap *idmap, + struct dentry *dentry, struct iattr *iattr); extern struct dentry *configfs_pin_fs(void); extern void configfs_release_fs(void); -extern struct rw_semaphore configfs_rename_sem; extern const struct file_operations configfs_dir_operations; extern const struct file_operations configfs_file_operations; -extern const struct file_operations bin_fops; +extern const struct file_operations configfs_bin_file_operations; extern const struct inode_operations configfs_dir_inode_operations; extern const struct inode_operations configfs_root_inode_operations; extern const struct inode_operations configfs_symlink_inode_operations; extern const struct dentry_operations configfs_dentry_ops; -extern int configfs_symlink(struct inode *dir, struct dentry *dentry, +extern int configfs_symlink(struct mnt_idmap *idmap, + struct inode *dir, struct dentry *dentry, const char *symname); extern int configfs_unlink(struct inode *dir, struct dentry *dentry); -struct configfs_symlink { - struct list_head sl_list; - struct config_item *sl_target; -}; - -extern int configfs_create_link(struct configfs_symlink *sl, - struct dentry *parent, - struct dentry *dentry); +int configfs_create_link(struct configfs_dirent *target, struct dentry *parent, + struct dentry *dentry, char *body); static inline struct config_item * to_item(struct dentry * dentry) { @@ -116,6 +111,13 @@ static inline struct configfs_attribute * to_attr(struct dentry * dentry) return ((struct configfs_attribute *) sd->s_element); } +static inline struct configfs_bin_attribute *to_bin_attr(struct dentry *dentry) +{ + struct configfs_attribute *attr = to_attr(dentry); + + return container_of(attr, struct configfs_bin_attribute, cb_attr); +} + static inline struct config_item *configfs_get_config_item(struct dentry *dentry) { struct config_item * item = NULL; @@ -123,11 +125,7 @@ static inline struct config_item *configfs_get_config_item(struct dentry *dentry spin_lock(&dentry->d_lock); if (!d_unhashed(dentry)) { struct configfs_dirent * sd = dentry->d_fsdata; - if (sd->s_type & CONFIGFS_ITEM_LINK) { - struct configfs_symlink * sl = sd->s_element; - item = config_item_get(sl->sl_target); - } else - item = config_item_get(sd->s_element); + item = config_item_get(sd->s_element); } spin_unlock(&dentry->d_lock); @@ -138,6 +136,7 @@ static inline void release_configfs_dirent(struct configfs_dirent * sd) { if (!(sd->s_type & CONFIGFS_ROOT)) { kfree(sd->s_iattr); + put_fragment(sd->s_frag); kmem_cache_free(configfs_dir_cachep, sd); } } diff --git a/fs/configfs/dir.c b/fs/configfs/dir.c index 277bd1be21fd..ba95f636a5ab 100644 --- a/fs/configfs/dir.c +++ b/fs/configfs/dir.c @@ -1,23 +1,7 @@ -/* -*- mode: c; c-basic-offset: 8; -*- - * vim: noexpandtab sw=8 ts=8 sts=0: - * +// SPDX-License-Identifier: GPL-2.0-or-later +/* * dir.c - Operations for configfs directories. * - * This program is free software; you can redistribute it and/or - * modify it under the terms of the GNU General Public - * License as published by the Free Software Foundation; either - * version 2 of the License, or (at your option) any later version. - * - * This program is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - * General Public License for more details. - * - * You should have received a copy of the GNU General Public - * License along with this program; if not, write to the - * Free Software Foundation, Inc., 59 Temple Place - Suite 330, - * Boston, MA 021110-1307, USA. - * * Based on sysfs: * sysfs is Copyright (C) 2001, 2002, 2003 Patrick Mochel * @@ -27,6 +11,7 @@ #undef DEBUG #include <linux/fs.h> +#include <linux/fsnotify.h> #include <linux/mount.h> #include <linux/module.h> #include <linux/slab.h> @@ -35,7 +20,6 @@ #include <linux/configfs.h> #include "configfs_internal.h" -DECLARE_RWSEM(configfs_rename_sem); /* * Protects mutations of configfs_dirent linkage together with proper i_mutex * Also protects mutations of symlinks linkage to target configfs_dirent @@ -50,35 +34,39 @@ DECLARE_RWSEM(configfs_rename_sem); */ DEFINE_SPINLOCK(configfs_dirent_lock); +/* + * All of link_obj/unlink_obj/link_group/unlink_group require that + * subsys->su_mutex is held. + * But parent configfs_subsystem is NULL when config_item is root. + * Use this mutex when config_item is root. + */ +static DEFINE_MUTEX(configfs_subsystem_mutex); + static void configfs_d_iput(struct dentry * dentry, struct inode * inode) { struct configfs_dirent *sd = dentry->d_fsdata; if (sd) { - BUG_ON(sd->s_dentry != dentry); /* Coordinate with configfs_readdir */ spin_lock(&configfs_dirent_lock); - sd->s_dentry = NULL; + /* + * Set sd->s_dentry to null only when this dentry is the one + * that is going to be killed. Otherwise configfs_d_iput may + * run just after configfs_lookup and set sd->s_dentry to + * NULL even it's still in use. + */ + if (sd->s_dentry == dentry) + sd->s_dentry = NULL; + spin_unlock(&configfs_dirent_lock); configfs_put(sd); } iput(inode); } -/* - * We _must_ delete our dentries on last dput, as the chain-to-parent - * behavior is required to clear the parents of default_groups. - */ -static int configfs_d_delete(const struct dentry *dentry) -{ - return 1; -} - const struct dentry_operations configfs_dentry_ops = { .d_iput = configfs_d_iput, - /* simple_delete_dentry() isn't exported */ - .d_delete = configfs_d_delete, }; #ifdef CONFIG_LOCKDEP @@ -167,11 +155,38 @@ configfs_adjust_dir_dirent_depth_after_populate(struct configfs_dirent *sd) #endif /* CONFIG_LOCKDEP */ +static struct configfs_fragment *new_fragment(void) +{ + struct configfs_fragment *p; + + p = kmalloc(sizeof(struct configfs_fragment), GFP_KERNEL); + if (p) { + atomic_set(&p->frag_count, 1); + init_rwsem(&p->frag_sem); + p->frag_dead = false; + } + return p; +} + +void put_fragment(struct configfs_fragment *frag) +{ + if (frag && atomic_dec_and_test(&frag->frag_count)) + kfree(frag); +} + +struct configfs_fragment *get_fragment(struct configfs_fragment *frag) +{ + if (likely(frag)) + atomic_inc(&frag->frag_count); + return frag; +} + /* * Allocates a new configfs_dirent and links it to the parent configfs_dirent */ static struct configfs_dirent *configfs_new_dirent(struct configfs_dirent *parent_sd, - void *element, int type) + void *element, int type, + struct configfs_fragment *frag) { struct configfs_dirent * sd; @@ -180,7 +195,6 @@ static struct configfs_dirent *configfs_new_dirent(struct configfs_dirent *paren return ERR_PTR(-ENOMEM); atomic_set(&sd->s_count, 1); - INIT_LIST_HEAD(&sd->s_links); INIT_LIST_HEAD(&sd->s_children); sd->s_element = element; sd->s_type = type; @@ -191,7 +205,18 @@ static struct configfs_dirent *configfs_new_dirent(struct configfs_dirent *paren kmem_cache_free(configfs_dir_cachep, sd); return ERR_PTR(-ENOENT); } - list_add(&sd->s_sibling, &parent_sd->s_children); + sd->s_frag = get_fragment(frag); + + /* + * configfs_lookup scans only for unpinned items. s_children is + * partitioned so that configfs_lookup can bail out early. + * CONFIGFS_PINNED and CONFIGFS_NOT_PINNED are not symmetrical. readdir + * cursors still need to be inserted at the front of the list. + */ + if (sd->s_type & CONFIGFS_PINNED) + list_add_tail(&sd->s_sibling, &parent_sd->s_children); + else + list_add(&sd->s_sibling, &parent_sd->s_children); spin_unlock(&configfs_dirent_lock); return sd; @@ -204,10 +229,11 @@ static struct configfs_dirent *configfs_new_dirent(struct configfs_dirent *paren * * called with parent inode's i_mutex held */ -static int configfs_dirent_exists(struct configfs_dirent *parent_sd, - const unsigned char *new) +static int configfs_dirent_exists(struct dentry *dentry) { - struct configfs_dirent * sd; + struct configfs_dirent *parent_sd = dentry->d_parent->d_fsdata; + const unsigned char *new = dentry->d_name.name; + struct configfs_dirent *sd; list_for_each_entry(sd, &parent_sd->s_children, s_sibling) { if (sd->s_element) { @@ -225,11 +251,11 @@ static int configfs_dirent_exists(struct configfs_dirent *parent_sd, int configfs_make_dirent(struct configfs_dirent * parent_sd, struct dentry * dentry, void * element, - umode_t mode, int type) + umode_t mode, int type, struct configfs_fragment *frag) { struct configfs_dirent * sd; - sd = configfs_new_dirent(parent_sd, element, type); + sd = configfs_new_dirent(parent_sd, element, type, frag); if (IS_ERR(sd)) return PTR_ERR(sd); @@ -241,75 +267,64 @@ int configfs_make_dirent(struct configfs_dirent * parent_sd, return 0; } -static int init_dir(struct inode * inode) -{ - inode->i_op = &configfs_dir_inode_operations; - inode->i_fop = &configfs_dir_operations; - - /* directory inodes start off with i_nlink == 2 (for "." entry) */ - inc_nlink(inode); - return 0; -} - -static int configfs_init_file(struct inode * inode) -{ - inode->i_size = PAGE_SIZE; - inode->i_fop = &configfs_file_operations; - return 0; -} - -static int init_symlink(struct inode * inode) +static void configfs_remove_dirent(struct dentry *dentry) { - inode->i_op = &configfs_symlink_inode_operations; - return 0; -} + struct configfs_dirent *sd = dentry->d_fsdata; -static int create_dir(struct config_item *k, struct dentry *d) -{ - int error; - umode_t mode = S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO; - struct dentry *p = d->d_parent; - - BUG_ON(!k); - - error = configfs_dirent_exists(p->d_fsdata, d->d_name.name); - if (!error) - error = configfs_make_dirent(p->d_fsdata, d, k, mode, - CONFIGFS_DIR | CONFIGFS_USET_CREATING); - if (!error) { - configfs_set_dir_dirent_depth(p->d_fsdata, d->d_fsdata); - error = configfs_create(d, mode, init_dir); - if (!error) { - inc_nlink(p->d_inode); - } else { - struct configfs_dirent *sd = d->d_fsdata; - if (sd) { - spin_lock(&configfs_dirent_lock); - list_del_init(&sd->s_sibling); - spin_unlock(&configfs_dirent_lock); - configfs_put(sd); - } - } - } - return error; + if (!sd) + return; + spin_lock(&configfs_dirent_lock); + list_del_init(&sd->s_sibling); + spin_unlock(&configfs_dirent_lock); + configfs_put(sd); } - /** * configfs_create_dir - create a directory for an config_item. * @item: config_itemwe're creating directory for. * @dentry: config_item's dentry. + * @frag: config_item's fragment. * * Note: user-created entries won't be allowed under this new directory * until it is validated by configfs_dir_set_ready() */ -static int configfs_create_dir(struct config_item * item, struct dentry *dentry) +static int configfs_create_dir(struct config_item *item, struct dentry *dentry, + struct configfs_fragment *frag) { - int error = create_dir(item, dentry); - if (!error) - item->ci_dentry = dentry; - return error; + int error; + umode_t mode = S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO; + struct dentry *p = dentry->d_parent; + struct inode *inode; + + BUG_ON(!item); + + error = configfs_make_dirent(p->d_fsdata, dentry, item, mode, + CONFIGFS_DIR | CONFIGFS_USET_CREATING, + frag); + if (unlikely(error)) + return error; + + configfs_set_dir_dirent_depth(p->d_fsdata, dentry->d_fsdata); + inode = configfs_create(dentry, mode); + if (IS_ERR(inode)) + goto out_remove; + + inode->i_op = &configfs_dir_inode_operations; + inode->i_fop = &configfs_dir_operations; + /* directory inodes start off with i_nlink == 2 (for "." entry) */ + inc_nlink(inode); + d_instantiate(dentry, inode); + /* already hashed */ + dget(dentry); /* pin directory dentries in core */ + inc_nlink(d_inode(p)); + item->ci_dentry = dentry; + return 0; + +out_remove: + configfs_put(dentry->d_fsdata); + configfs_remove_dirent(dentry); + return PTR_ERR(inode); } /* @@ -350,44 +365,51 @@ int configfs_dirent_is_ready(struct configfs_dirent *sd) return ret; } -int configfs_create_link(struct configfs_symlink *sl, - struct dentry *parent, - struct dentry *dentry) +int configfs_create_link(struct configfs_dirent *target, struct dentry *parent, + struct dentry *dentry, char *body) { int err = 0; umode_t mode = S_IFLNK | S_IRWXUGO; + struct configfs_dirent *p = parent->d_fsdata; + struct inode *inode; - err = configfs_make_dirent(parent->d_fsdata, dentry, sl, mode, - CONFIGFS_ITEM_LINK); - if (!err) { - err = configfs_create(dentry, mode, init_symlink); - if (err) { - struct configfs_dirent *sd = dentry->d_fsdata; - if (sd) { - spin_lock(&configfs_dirent_lock); - list_del_init(&sd->s_sibling); - spin_unlock(&configfs_dirent_lock); - configfs_put(sd); - } - } - } - return err; + err = configfs_make_dirent(p, dentry, target, mode, CONFIGFS_ITEM_LINK, + p->s_frag); + if (err) + return err; + + inode = configfs_create(dentry, mode); + if (IS_ERR(inode)) + goto out_remove; + + inode->i_link = body; + inode->i_op = &configfs_symlink_inode_operations; + d_instantiate(dentry, inode); + dget(dentry); /* pin link dentries in core */ + return 0; + +out_remove: + configfs_put(dentry->d_fsdata); + configfs_remove_dirent(dentry); + return PTR_ERR(inode); } static void remove_dir(struct dentry * d) { struct dentry * parent = dget(d->d_parent); - struct configfs_dirent * sd; - sd = d->d_fsdata; - spin_lock(&configfs_dirent_lock); - list_del_init(&sd->s_sibling); - spin_unlock(&configfs_dirent_lock); - configfs_put(sd); - if (d->d_inode) - simple_rmdir(parent->d_inode,d); + configfs_remove_dirent(d); - pr_debug(" o %s removing done (%d)\n",d->d_name.name, d_count(d)); + if (d_really_is_positive(d)) { + if (likely(simple_empty(d))) { + __simple_rmdir(d_inode(parent),d); + dput(d); + } else { + pr_warn("remove_dir (%pd): attributes remain", d); + } + } + + pr_debug(" o %pd removing done (%d)\n", d, d_count(d)); dput(parent); } @@ -417,37 +439,16 @@ static void configfs_remove_dir(struct config_item * item) dput(dentry); } - -/* attaches attribute's configfs_dirent to the dentry corresponding to the - * attribute file - */ -static int configfs_attach_attr(struct configfs_dirent * sd, struct dentry * dentry) -{ - struct configfs_attribute * attr = sd->s_element; - int error; - - dentry->d_fsdata = configfs_get(sd); - sd->s_dentry = dentry; - error = configfs_create(dentry, (attr->ca_mode & S_IALLUGO) | S_IFREG, - configfs_init_file); - if (error) { - configfs_put(sd); - return error; - } - - d_rehash(dentry); - - return 0; -} - static struct dentry * configfs_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags) { struct configfs_dirent * parent_sd = dentry->d_parent->d_fsdata; struct configfs_dirent * sd; - int found = 0; - int err; + struct inode *inode = NULL; + + if (dentry->d_name.len > NAME_MAX) + return ERR_PTR(-ENAMETOOLONG); /* * Fake invisibility if dir belongs to a group/default groups hierarchy @@ -457,36 +458,51 @@ static struct dentry * configfs_lookup(struct inode *dir, * not complete their initialization, since the dentries of the * attributes won't be instantiated. */ - err = -ENOENT; if (!configfs_dirent_is_ready(parent_sd)) - goto out; + return ERR_PTR(-ENOENT); + spin_lock(&configfs_dirent_lock); list_for_each_entry(sd, &parent_sd->s_children, s_sibling) { - if (sd->s_type & CONFIGFS_NOT_PINNED) { - const unsigned char * name = configfs_get_name(sd); - - if (strcmp(name, dentry->d_name.name)) - continue; - found = 1; - err = configfs_attach_attr(sd, dentry); + /* + * s_children is partitioned, see configfs_new_dirent. The first + * pinned item indicates we can stop scanning. + */ + if (sd->s_type & CONFIGFS_PINNED) break; - } - } - if (!found) { /* - * If it doesn't exist and it isn't a NOT_PINNED item, - * it must be negative. + * Note: CONFIGFS_PINNED and CONFIGFS_NOT_PINNED are asymmetric. + * there may be a readdir cursor in this list */ - if (dentry->d_name.len > NAME_MAX) - return ERR_PTR(-ENAMETOOLONG); - d_add(dentry, NULL); - return NULL; - } + if ((sd->s_type & CONFIGFS_NOT_PINNED) && + !strcmp(configfs_get_name(sd), dentry->d_name.name)) { + struct configfs_attribute *attr = sd->s_element; + umode_t mode = (attr->ca_mode & S_IALLUGO) | S_IFREG; -out: - return ERR_PTR(err); + dentry->d_fsdata = configfs_get(sd); + sd->s_dentry = dentry; + spin_unlock(&configfs_dirent_lock); + + inode = configfs_create(dentry, mode); + if (IS_ERR(inode)) { + configfs_put(sd); + return ERR_CAST(inode); + } + if (sd->s_type & CONFIGFS_ITEM_BIN_ATTR) { + inode->i_size = 0; + inode->i_fop = &configfs_bin_file_operations; + } else { + inode->i_size = PAGE_SIZE; + inode->i_fop = &configfs_file_operations; + } + goto done; + } + } + spin_unlock(&configfs_dirent_lock); +done: + d_add(dentry, inode); + return NULL; } /* @@ -497,7 +513,7 @@ out: * If there is an error, the caller will reset the flags via * configfs_detach_rollback(). */ -static int configfs_detach_prep(struct dentry *dentry, struct mutex **wait_mutex) +static int configfs_detach_prep(struct dentry *dentry, struct dentry **wait) { struct configfs_dirent *parent_sd = dentry->d_fsdata; struct configfs_dirent *sd; @@ -507,7 +523,7 @@ static int configfs_detach_prep(struct dentry *dentry, struct mutex **wait_mutex parent_sd->s_type |= CONFIGFS_USET_DROPPING; ret = -EBUSY; - if (!list_empty(&parent_sd->s_links)) + if (parent_sd->s_links) goto out; ret = 0; @@ -518,8 +534,8 @@ static int configfs_detach_prep(struct dentry *dentry, struct mutex **wait_mutex if (sd->s_type & CONFIGFS_USET_DEFAULT) { /* Abort if racing with mkdir() */ if (sd->s_type & CONFIGFS_USET_IN_MKDIR) { - if (wait_mutex) - *wait_mutex = &sd->s_dentry->d_inode->i_mutex; + if (wait) + *wait= dget(sd->s_dentry); return -EAGAIN; } @@ -527,7 +543,7 @@ static int configfs_detach_prep(struct dentry *dentry, struct mutex **wait_mutex * Yup, recursive. If there's a problem, blame * deep nesting of default_groups */ - ret = configfs_detach_prep(sd->s_dentry, wait_mutex); + ret = configfs_detach_prep(sd->s_dentry, wait); if (!ret) continue; } else @@ -587,19 +603,37 @@ static void detach_attrs(struct config_item * item) static int populate_attrs(struct config_item *item) { - struct config_item_type *t = item->ci_type; + const struct config_item_type *t = item->ci_type; + const struct configfs_group_operations *ops; struct configfs_attribute *attr; + struct configfs_bin_attribute *bin_attr; int error = 0; int i; if (!t) return -EINVAL; + + ops = t->ct_group_ops; + if (t->ct_attrs) { for (i = 0; (attr = t->ct_attrs[i]) != NULL; i++) { + if (ops && ops->is_visible && !ops->is_visible(item, attr, i)) + continue; + if ((error = configfs_create_file(item, attr))) break; } } + if (!error && t->ct_bin_attrs) { + for (i = 0; (bin_attr = t->ct_bin_attrs[i]) != NULL; i++) { + if (ops && ops->is_bin_visible && !ops->is_bin_visible(item, bin_attr, i)) + continue; + + error = configfs_create_bin_file(item, bin_attr); + if (error) + break; + } + } if (error) detach_attrs(item); @@ -609,7 +643,8 @@ static int populate_attrs(struct config_item *item) static int configfs_attach_group(struct config_item *parent_item, struct config_item *item, - struct dentry *dentry); + struct dentry *dentry, + struct configfs_fragment *frag); static void configfs_detach_group(struct config_item *item); static void detach_groups(struct config_group *group) @@ -630,13 +665,13 @@ static void detach_groups(struct config_group *group) child = sd->s_dentry; - mutex_lock(&child->d_inode->i_mutex); + inode_lock(d_inode(child)); configfs_detach_group(sd->s_element); - child->d_inode->i_flags |= S_DEAD; + d_inode(child)->i_flags |= S_DEAD; dont_mount(child); - mutex_unlock(&child->d_inode->i_mutex); + inode_unlock(d_inode(child)); d_delete(child); dput(child); @@ -657,7 +692,8 @@ static void detach_groups(struct config_group *group) * try using vfs_mkdir. Just a thought. */ static int create_default_group(struct config_group *parent_group, - struct config_group *group) + struct config_group *group, + struct configfs_fragment *frag) { int ret; struct configfs_dirent *sd; @@ -673,12 +709,12 @@ static int create_default_group(struct config_group *parent_group, d_add(child, NULL); ret = configfs_attach_group(&parent_group->cg_item, - &group->cg_item, child); + &group->cg_item, child, frag); if (!ret) { sd = child->d_fsdata; sd->s_type |= CONFIGFS_USET_DEFAULT; } else { - BUG_ON(child->d_inode); + BUG_ON(d_inode(child)); d_drop(child); dput(child); } @@ -687,27 +723,34 @@ static int create_default_group(struct config_group *parent_group, return ret; } -static int populate_groups(struct config_group *group) +static int populate_groups(struct config_group *group, + struct configfs_fragment *frag) { struct config_group *new_group; int ret = 0; - int i; - - if (group->default_groups) { - for (i = 0; group->default_groups[i]; i++) { - new_group = group->default_groups[i]; - ret = create_default_group(group, new_group); - if (ret) { - detach_groups(group); - break; - } + list_for_each_entry(new_group, &group->default_groups, group_entry) { + ret = create_default_group(group, new_group, frag); + if (ret) { + detach_groups(group); + break; } } return ret; } +void configfs_remove_default_groups(struct config_group *group) +{ + struct config_group *g, *n; + + list_for_each_entry_safe(g, n, &group->default_groups, group_entry) { + list_del(&g->group_entry); + config_item_put(&g->cg_item); + } +} +EXPORT_SYMBOL(configfs_remove_default_groups); + /* * All of link_obj/unlink_obj/link_group/unlink_group require that * subsys->su_mutex is held. @@ -756,15 +799,10 @@ static void link_obj(struct config_item *parent_item, struct config_item *item) static void unlink_group(struct config_group *group) { - int i; struct config_group *new_group; - if (group->default_groups) { - for (i = 0; group->default_groups[i]; i++) { - new_group = group->default_groups[i]; - unlink_group(new_group); - } - } + list_for_each_entry(new_group, &group->default_groups, group_entry) + unlink_group(new_group); group->cg_subsys = NULL; unlink_obj(&group->cg_item); @@ -772,7 +810,6 @@ static void unlink_group(struct config_group *group) static void link_group(struct config_group *parent_group, struct config_group *group) { - int i; struct config_group *new_group; struct configfs_subsystem *subsys = NULL; /* gcc is a turd */ @@ -786,12 +823,8 @@ static void link_group(struct config_group *parent_group, struct config_group *g BUG(); group->cg_subsys = subsys; - if (group->default_groups) { - for (i = 0; group->default_groups[i]; i++) { - new_group = group->default_groups[i]; - link_group(group, new_group); - } - } + list_for_each_entry(new_group, &group->default_groups, group_entry) + link_group(group, new_group); } /* @@ -811,11 +844,12 @@ static void link_group(struct config_group *parent_group, struct config_group *g */ static int configfs_attach_item(struct config_item *parent_item, struct config_item *item, - struct dentry *dentry) + struct dentry *dentry, + struct configfs_fragment *frag) { int ret; - ret = configfs_create_dir(item, dentry); + ret = configfs_create_dir(item, dentry, frag); if (!ret) { ret = populate_attrs(item); if (ret) { @@ -824,11 +858,11 @@ static int configfs_attach_item(struct config_item *parent_item, * the VFS may already have hit and used them. Thus, * we must lock them as rmdir() would. */ - mutex_lock(&dentry->d_inode->i_mutex); + inode_lock(d_inode(dentry)); configfs_remove_dir(item); - dentry->d_inode->i_flags |= S_DEAD; + d_inode(dentry)->i_flags |= S_DEAD; dont_mount(dentry); - mutex_unlock(&dentry->d_inode->i_mutex); + inode_unlock(d_inode(dentry)); d_delete(dentry); } } @@ -845,12 +879,13 @@ static void configfs_detach_item(struct config_item *item) static int configfs_attach_group(struct config_item *parent_item, struct config_item *item, - struct dentry *dentry) + struct dentry *dentry, + struct configfs_fragment *frag) { int ret; struct configfs_dirent *sd; - ret = configfs_attach_item(parent_item, item, dentry); + ret = configfs_attach_item(parent_item, item, dentry, frag); if (!ret) { sd = dentry->d_fsdata; sd->s_type |= CONFIGFS_USET_DIR; @@ -864,16 +899,16 @@ static int configfs_attach_group(struct config_item *parent_item, * We must also lock the inode to remove it safely in case of * error, as rmdir() would. */ - mutex_lock_nested(&dentry->d_inode->i_mutex, I_MUTEX_CHILD); + inode_lock_nested(d_inode(dentry), I_MUTEX_CHILD); configfs_adjust_dir_dirent_depth_before_populate(sd); - ret = populate_groups(to_config_group(item)); + ret = populate_groups(to_config_group(item), frag); if (ret) { configfs_detach_item(item); - dentry->d_inode->i_flags |= S_DEAD; + d_inode(dentry)->i_flags |= S_DEAD; dont_mount(dentry); } configfs_adjust_dir_dirent_depth_after_populate(sd); - mutex_unlock(&dentry->d_inode->i_mutex); + inode_unlock(d_inode(dentry)); if (ret) d_delete(dentry); } @@ -900,7 +935,7 @@ static void configfs_detach_group(struct config_item *item) static void client_disconnect_notify(struct config_item *parent_item, struct config_item *item) { - struct config_item_type *type; + const struct config_item_type *type; type = parent_item->ci_type; BUG_ON(!type); @@ -919,7 +954,7 @@ static void client_disconnect_notify(struct config_item *parent_item, static void client_drop_item(struct config_item *parent_item, struct config_item *item) { - struct config_item_type *type; + const struct config_item_type *type; type = parent_item->ci_type; BUG_ON(!type); @@ -938,9 +973,9 @@ static void client_drop_item(struct config_item *parent_item, #ifdef DEBUG static void configfs_dump_one(struct configfs_dirent *sd, int level) { - printk(KERN_INFO "%*s\"%s\":\n", level, " ", configfs_get_name(sd)); + pr_info("%*s\"%s\":\n", level, " ", configfs_get_name(sd)); -#define type_print(_type) if (sd->s_type & _type) printk(KERN_INFO "%*s %s\n", level, " ", #_type); +#define type_print(_type) if (sd->s_type & _type) pr_info("%*s %s\n", level, " ", #_type) type_print(CONFIGFS_ROOT); type_print(CONFIGFS_DIR); type_print(CONFIGFS_ITEM_ATTR); @@ -1060,11 +1095,55 @@ out: return ret; } +static int configfs_do_depend_item(struct dentry *subsys_dentry, + struct config_item *target) +{ + struct configfs_dirent *p; + int ret; + + spin_lock(&configfs_dirent_lock); + /* Scan the tree, return 0 if found */ + ret = configfs_depend_prep(subsys_dentry, target); + if (ret) + goto out_unlock_dirent_lock; + + /* + * We are sure that the item is not about to be removed by rmdir(), and + * not in the middle of attachment by mkdir(). + */ + p = target->ci_dentry->d_fsdata; + p->s_dependent_count += 1; + +out_unlock_dirent_lock: + spin_unlock(&configfs_dirent_lock); + + return ret; +} + +static inline struct configfs_dirent * +configfs_find_subsys_dentry(struct configfs_dirent *root_sd, + struct config_item *subsys_item) +{ + struct configfs_dirent *p; + struct configfs_dirent *ret = NULL; + + list_for_each_entry(p, &root_sd->s_children, s_sibling) { + if (p->s_type & CONFIGFS_DIR && + p->s_element == subsys_item) { + ret = p; + break; + } + } + + return ret; +} + + int configfs_depend_item(struct configfs_subsystem *subsys, struct config_item *target) { int ret; - struct configfs_dirent *p, *root_sd, *subsys_sd = NULL; + struct configfs_dirent *subsys_sd; struct config_item *s_item = &subsys->su_group.cg_item; struct dentry *root; @@ -1081,43 +1160,19 @@ int configfs_depend_item(struct configfs_subsystem *subsys, * subsystem is really registered, and so we need to lock out * configfs_[un]register_subsystem(). */ - mutex_lock(&root->d_inode->i_mutex); - - root_sd = root->d_fsdata; - - list_for_each_entry(p, &root_sd->s_children, s_sibling) { - if (p->s_type & CONFIGFS_DIR) { - if (p->s_element == s_item) { - subsys_sd = p; - break; - } - } - } + inode_lock(d_inode(root)); + subsys_sd = configfs_find_subsys_dentry(root->d_fsdata, s_item); if (!subsys_sd) { ret = -ENOENT; goto out_unlock_fs; } /* Ok, now we can trust subsys/s_item */ + ret = configfs_do_depend_item(subsys_sd->s_dentry, target); - spin_lock(&configfs_dirent_lock); - /* Scan the tree, return 0 if found */ - ret = configfs_depend_prep(subsys_sd->s_dentry, target); - if (ret) - goto out_unlock_dirent_lock; - - /* - * We are sure that the item is not about to be removed by rmdir(), and - * not in the middle of attachment by mkdir(). - */ - p = target->ci_dentry->d_fsdata; - p->s_dependent_count += 1; - -out_unlock_dirent_lock: - spin_unlock(&configfs_dirent_lock); out_unlock_fs: - mutex_unlock(&root->d_inode->i_mutex); + inode_unlock(d_inode(root)); /* * If we succeeded, the fs is pinned via other methods. If not, @@ -1131,11 +1186,10 @@ EXPORT_SYMBOL(configfs_depend_item); /* * Release the dependent linkage. This is much simpler than - * configfs_depend_item() because we know that that the client driver is + * configfs_depend_item() because we know that the client driver is * pinned, thus the subsystem is pinned, and therefore configfs is pinned. */ -void configfs_undepend_item(struct configfs_subsystem *subsys, - struct config_item *target) +void configfs_undepend_item(struct config_item *target) { struct configfs_dirent *sd; @@ -1158,7 +1212,81 @@ void configfs_undepend_item(struct configfs_subsystem *subsys, } EXPORT_SYMBOL(configfs_undepend_item); -static int configfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) +/* + * caller_subsys is a caller's subsystem not target's. This is used to + * determine if we should lock root and check subsys or not. When we are + * in the same subsystem as our target there is no need to do locking as + * we know that subsys is valid and is not unregistered during this function + * as we are called from callback of one of his children and VFS holds a lock + * on some inode. Otherwise we have to lock our root to ensure that target's + * subsystem it is not unregistered during this function. + */ +int configfs_depend_item_unlocked(struct configfs_subsystem *caller_subsys, + struct config_item *target) +{ + struct configfs_subsystem *target_subsys; + struct config_group *root, *parent; + struct configfs_dirent *subsys_sd; + int ret = -ENOENT; + + /* Disallow this function for configfs root */ + if (configfs_is_root(target)) + return -EINVAL; + + parent = target->ci_group; + /* + * This may happen when someone is trying to depend root + * directory of some subsystem + */ + if (configfs_is_root(&parent->cg_item)) { + target_subsys = to_configfs_subsystem(to_config_group(target)); + root = parent; + } else { + target_subsys = parent->cg_subsys; + /* Find a cofnigfs root as we may need it for locking */ + for (root = parent; !configfs_is_root(&root->cg_item); + root = root->cg_item.ci_group) + ; + } + + if (target_subsys != caller_subsys) { + /* + * We are in other configfs subsystem, so we have to do + * additional locking to prevent other subsystem from being + * unregistered + */ + inode_lock(d_inode(root->cg_item.ci_dentry)); + + /* + * As we are trying to depend item from other subsystem + * we have to check if this subsystem is still registered + */ + subsys_sd = configfs_find_subsys_dentry( + root->cg_item.ci_dentry->d_fsdata, + &target_subsys->su_group.cg_item); + if (!subsys_sd) + goto out_root_unlock; + } else { + subsys_sd = target_subsys->su_group.cg_item.ci_dentry->d_fsdata; + } + + /* Now we can execute core of depend item */ + ret = configfs_do_depend_item(subsys_sd->s_dentry, target); + + if (target_subsys != caller_subsys) +out_root_unlock: + /* + * We were called from subsystem other than our target so we + * took some locks so now it's time to release them + */ + inode_unlock(d_inode(root->cg_item.ci_dentry)); + + return ret; +} +EXPORT_SYMBOL(configfs_depend_item_unlocked); + +static struct dentry *configfs_mkdir(struct mnt_idmap *idmap, struct inode *dir, + struct dentry *dentry, umode_t mode) { int ret = 0; int module_got = 0; @@ -1167,8 +1295,9 @@ static int configfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode struct config_item *parent_item; struct configfs_subsystem *subsys; struct configfs_dirent *sd; - struct config_item_type *type; + const struct config_item_type *type; struct module *subsys_owner = NULL, *new_item_owner = NULL; + struct configfs_fragment *frag; char *name; sd = dentry->d_parent->d_fsdata; @@ -1187,6 +1316,12 @@ static int configfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode goto out; } + frag = new_fragment(); + if (!frag) { + ret = -ENOMEM; + goto out; + } + /* Get a working ref for the duration of this function */ parent_item = configfs_get_config_item(dentry->d_parent); type = parent_item->ci_type; @@ -1289,9 +1424,9 @@ static int configfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode spin_unlock(&configfs_dirent_lock); if (group) - ret = configfs_attach_group(parent_item, item, dentry); + ret = configfs_attach_group(parent_item, item, dentry, frag); else - ret = configfs_attach_item(parent_item, item, dentry); + ret = configfs_attach_item(parent_item, item, dentry, frag); spin_lock(&configfs_dirent_lock); sd->s_type &= ~CONFIGFS_USET_IN_MKDIR; @@ -1328,9 +1463,10 @@ out_put: * reference. */ config_item_put(parent_item); + put_fragment(frag); out: - return ret; + return ERR_PTR(ret); } static int configfs_rmdir(struct inode *dir, struct dentry *dentry) @@ -1339,6 +1475,7 @@ static int configfs_rmdir(struct inode *dir, struct dentry *dentry) struct config_item *item; struct configfs_subsystem *subsys; struct configfs_dirent *sd; + struct configfs_fragment *frag; struct module *subsys_owner = NULL, *dead_item_owner = NULL; int ret; @@ -1365,7 +1502,7 @@ static int configfs_rmdir(struct inode *dir, struct dentry *dentry) * the new link is temporarily attached */ do { - struct mutex *wait_mutex; + struct dentry *wait; mutex_lock(&configfs_symlink_mutex); spin_lock(&configfs_dirent_lock); @@ -1376,7 +1513,7 @@ static int configfs_rmdir(struct inode *dir, struct dentry *dentry) */ ret = sd->s_dependent_count ? -EBUSY : 0; if (!ret) { - ret = configfs_detach_prep(dentry, &wait_mutex); + ret = configfs_detach_prep(dentry, &wait); if (ret) configfs_detach_rollback(dentry); } @@ -1390,11 +1527,23 @@ static int configfs_rmdir(struct inode *dir, struct dentry *dentry) } /* Wait until the racing operation terminates */ - mutex_lock(wait_mutex); - mutex_unlock(wait_mutex); + inode_lock(d_inode(wait)); + inode_unlock(d_inode(wait)); + dput(wait); } } while (ret == -EAGAIN); + frag = sd->s_frag; + if (down_write_killable(&frag->frag_sem)) { + spin_lock(&configfs_dirent_lock); + configfs_detach_rollback(dentry); + spin_unlock(&configfs_dirent_lock); + config_item_put(parent_item); + return -EINTR; + } + frag->frag_dead = true; + up_write(&frag->frag_sem); + /* Get a working ref for the duration of this function */ item = configfs_get_config_item(dentry); @@ -1444,64 +1593,23 @@ const struct inode_operations configfs_root_inode_operations = { .setattr = configfs_setattr, }; -#if 0 -int configfs_rename_dir(struct config_item * item, const char *new_name) -{ - int error = 0; - struct dentry * new_dentry, * parent; - - if (!strcmp(config_item_name(item), new_name)) - return -EINVAL; - - if (!item->parent) - return -EINVAL; - - down_write(&configfs_rename_sem); - parent = item->parent->dentry; - - mutex_lock(&parent->d_inode->i_mutex); - - new_dentry = lookup_one_len(new_name, parent, strlen(new_name)); - if (!IS_ERR(new_dentry)) { - if (!new_dentry->d_inode) { - error = config_item_set_name(item, "%s", new_name); - if (!error) { - d_add(new_dentry, NULL); - d_move(item->dentry, new_dentry); - } - else - d_delete(new_dentry); - } else - error = -EEXIST; - dput(new_dentry); - } - mutex_unlock(&parent->d_inode->i_mutex); - up_write(&configfs_rename_sem); - - return error; -} -#endif - static int configfs_dir_open(struct inode *inode, struct file *file) { struct dentry * dentry = file->f_path.dentry; struct configfs_dirent * parent_sd = dentry->d_fsdata; int err; - mutex_lock(&dentry->d_inode->i_mutex); + inode_lock(d_inode(dentry)); /* * Fake invisibility if dir belongs to a group/default groups hierarchy * being attached */ err = -ENOENT; if (configfs_dirent_is_ready(parent_sd)) { - file->private_data = configfs_new_dirent(parent_sd, NULL, 0); - if (IS_ERR(file->private_data)) - err = PTR_ERR(file->private_data); - else - err = 0; + file->private_data = configfs_new_dirent(parent_sd, NULL, 0, NULL); + err = PTR_ERR_OR_ZERO(file->private_data); } - mutex_unlock(&dentry->d_inode->i_mutex); + inode_unlock(d_inode(dentry)); return err; } @@ -1511,23 +1619,17 @@ static int configfs_dir_close(struct inode *inode, struct file *file) struct dentry * dentry = file->f_path.dentry; struct configfs_dirent * cursor = file->private_data; - mutex_lock(&dentry->d_inode->i_mutex); + inode_lock(d_inode(dentry)); spin_lock(&configfs_dirent_lock); list_del_init(&cursor->s_sibling); spin_unlock(&configfs_dirent_lock); - mutex_unlock(&dentry->d_inode->i_mutex); + inode_unlock(d_inode(dentry)); release_configfs_dirent(cursor); return 0; } -/* Relationship between s_mode and the DT_xxx types */ -static inline unsigned char dt_type(struct configfs_dirent *sd) -{ - return (sd->s_mode >> 12) & 15; -} - static int configfs_readdir(struct file *file, struct dir_context *ctx) { struct dentry *dentry = file->f_path.dentry; @@ -1539,11 +1641,9 @@ static int configfs_readdir(struct file *file, struct dir_context *ctx) if (!dir_emit_dots(file, ctx)) return 0; - if (ctx->pos == 2) { - spin_lock(&configfs_dirent_lock); + spin_lock(&configfs_dirent_lock); + if (ctx->pos == 2) list_move(q, &parent_sd->s_children); - spin_unlock(&configfs_dirent_lock); - } for (p = q->next; p != &parent_sd->s_children; p = p->next) { struct configfs_dirent *next; const char *name; @@ -1554,9 +1654,6 @@ static int configfs_readdir(struct file *file, struct dir_context *ctx) if (!next->s_element) continue; - name = configfs_get_name(next); - len = strlen(name); - /* * We'll have a dentry and an inode for * PINNED items and for open attribute @@ -1570,25 +1667,28 @@ static int configfs_readdir(struct file *file, struct dir_context *ctx) * they close it. Beyond that, we don't * care. */ - spin_lock(&configfs_dirent_lock); dentry = next->s_dentry; if (dentry) - inode = dentry->d_inode; + inode = d_inode(dentry); if (inode) ino = inode->i_ino; spin_unlock(&configfs_dirent_lock); if (!inode) ino = iunique(sb, 2); - if (!dir_emit(ctx, name, len, ino, dt_type(next))) + name = configfs_get_name(next); + len = strlen(name); + + if (!dir_emit(ctx, name, len, ino, + fs_umode_to_dtype(next->s_mode))) return 0; spin_lock(&configfs_dirent_lock); list_move(q, p); - spin_unlock(&configfs_dirent_lock); p = q; ctx->pos++; } + spin_unlock(&configfs_dirent_lock); return 0; } @@ -1596,15 +1696,15 @@ static loff_t configfs_dir_lseek(struct file *file, loff_t offset, int whence) { struct dentry * dentry = file->f_path.dentry; - mutex_lock(&dentry->d_inode->i_mutex); switch (whence) { case 1: offset += file->f_pos; + fallthrough; case 0: if (offset >= 0) break; + fallthrough; default: - mutex_unlock(&file_inode(file)->i_mutex); return -EINVAL; } if (offset != file->f_pos) { @@ -1630,7 +1730,6 @@ static loff_t configfs_dir_lseek(struct file *file, loff_t offset, int whence) spin_unlock(&configfs_dirent_lock); } } - mutex_unlock(&dentry->d_inode->i_mutex); return offset; } @@ -1639,9 +1738,140 @@ const struct file_operations configfs_dir_operations = { .release = configfs_dir_close, .llseek = configfs_dir_lseek, .read = generic_read_dir, - .iterate = configfs_readdir, + .iterate_shared = configfs_readdir, }; +/** + * configfs_register_group - creates a parent-child relation between two groups + * @parent_group: parent group + * @group: child group + * + * link groups, creates dentry for the child and attaches it to the + * parent dentry. + * + * Return: 0 on success, negative errno code on error + */ +int configfs_register_group(struct config_group *parent_group, + struct config_group *group) +{ + struct configfs_subsystem *subsys = parent_group->cg_subsys; + struct dentry *parent; + struct configfs_fragment *frag; + int ret; + + frag = new_fragment(); + if (!frag) + return -ENOMEM; + + mutex_lock(&subsys->su_mutex); + link_group(parent_group, group); + mutex_unlock(&subsys->su_mutex); + + parent = parent_group->cg_item.ci_dentry; + + inode_lock_nested(d_inode(parent), I_MUTEX_PARENT); + ret = create_default_group(parent_group, group, frag); + if (ret) + goto err_out; + + spin_lock(&configfs_dirent_lock); + configfs_dir_set_ready(group->cg_item.ci_dentry->d_fsdata); + spin_unlock(&configfs_dirent_lock); + inode_unlock(d_inode(parent)); + put_fragment(frag); + return 0; +err_out: + inode_unlock(d_inode(parent)); + mutex_lock(&subsys->su_mutex); + unlink_group(group); + mutex_unlock(&subsys->su_mutex); + put_fragment(frag); + return ret; +} +EXPORT_SYMBOL(configfs_register_group); + +/** + * configfs_unregister_group() - unregisters a child group from its parent + * @group: parent group to be unregistered + * + * Undoes configfs_register_group() + */ +void configfs_unregister_group(struct config_group *group) +{ + struct configfs_subsystem *subsys = group->cg_subsys; + struct dentry *dentry = group->cg_item.ci_dentry; + struct dentry *parent = group->cg_item.ci_parent->ci_dentry; + struct configfs_dirent *sd = dentry->d_fsdata; + struct configfs_fragment *frag = sd->s_frag; + + down_write(&frag->frag_sem); + frag->frag_dead = true; + up_write(&frag->frag_sem); + + inode_lock_nested(d_inode(parent), I_MUTEX_PARENT); + spin_lock(&configfs_dirent_lock); + configfs_detach_prep(dentry, NULL); + spin_unlock(&configfs_dirent_lock); + + configfs_detach_group(&group->cg_item); + d_inode(dentry)->i_flags |= S_DEAD; + dont_mount(dentry); + d_drop(dentry); + fsnotify_rmdir(d_inode(parent), dentry); + inode_unlock(d_inode(parent)); + + dput(dentry); + + mutex_lock(&subsys->su_mutex); + unlink_group(group); + mutex_unlock(&subsys->su_mutex); +} +EXPORT_SYMBOL(configfs_unregister_group); + +/** + * configfs_register_default_group() - allocates and registers a child group + * @parent_group: parent group + * @name: child group name + * @item_type: child item type description + * + * boilerplate to allocate and register a child group with its parent. We need + * kzalloc'ed memory because child's default_group is initially empty. + * + * Return: allocated config group or ERR_PTR() on error + */ +struct config_group * +configfs_register_default_group(struct config_group *parent_group, + const char *name, + const struct config_item_type *item_type) +{ + int ret; + struct config_group *group; + + group = kzalloc(sizeof(*group), GFP_KERNEL); + if (!group) + return ERR_PTR(-ENOMEM); + config_group_init_type_name(group, name, item_type); + + ret = configfs_register_group(parent_group, group); + if (ret) { + kfree(group); + return ERR_PTR(ret); + } + return group; +} +EXPORT_SYMBOL(configfs_register_default_group); + +/** + * configfs_unregister_default_group() - unregisters and frees a child group + * @group: the group to act on + */ +void configfs_unregister_default_group(struct config_group *group) +{ + configfs_unregister_group(group); + kfree(group); +} +EXPORT_SYMBOL(configfs_unregister_default_group); + int configfs_register_subsystem(struct configfs_subsystem *subsys) { int err; @@ -1649,28 +1879,40 @@ int configfs_register_subsystem(struct configfs_subsystem *subsys) struct dentry *dentry; struct dentry *root; struct configfs_dirent *sd; + struct configfs_fragment *frag; + + frag = new_fragment(); + if (!frag) + return -ENOMEM; root = configfs_pin_fs(); - if (IS_ERR(root)) + if (IS_ERR(root)) { + put_fragment(frag); return PTR_ERR(root); + } if (!group->cg_item.ci_name) group->cg_item.ci_name = group->cg_item.ci_namebuf; sd = root->d_fsdata; + mutex_lock(&configfs_subsystem_mutex); link_group(to_config_group(sd->s_element), group); + mutex_unlock(&configfs_subsystem_mutex); - mutex_lock_nested(&root->d_inode->i_mutex, I_MUTEX_PARENT); + inode_lock_nested(d_inode(root), I_MUTEX_PARENT); err = -ENOMEM; dentry = d_alloc_name(root, group->cg_item.ci_name); if (dentry) { d_add(dentry, NULL); - err = configfs_attach_group(sd->s_element, &group->cg_item, - dentry); + err = configfs_dirent_exists(dentry); + if (!err) + err = configfs_attach_group(sd->s_element, + &group->cg_item, + dentry, frag); if (err) { - BUG_ON(dentry->d_inode); + BUG_ON(d_inode(dentry)); d_drop(dentry); dput(dentry); } else { @@ -1680,12 +1922,15 @@ int configfs_register_subsystem(struct configfs_subsystem *subsys) } } - mutex_unlock(&root->d_inode->i_mutex); + inode_unlock(d_inode(root)); if (err) { + mutex_lock(&configfs_subsystem_mutex); unlink_group(group); + mutex_unlock(&configfs_subsystem_mutex); configfs_release_fs(); } + put_fragment(frag); return err; } @@ -1695,34 +1940,43 @@ void configfs_unregister_subsystem(struct configfs_subsystem *subsys) struct config_group *group = &subsys->su_group; struct dentry *dentry = group->cg_item.ci_dentry; struct dentry *root = dentry->d_sb->s_root; + struct configfs_dirent *sd = dentry->d_fsdata; + struct configfs_fragment *frag = sd->s_frag; if (dentry->d_parent != root) { - printk(KERN_ERR "configfs: Tried to unregister non-subsystem!\n"); + pr_err("Tried to unregister non-subsystem!\n"); return; } - mutex_lock_nested(&root->d_inode->i_mutex, + down_write(&frag->frag_sem); + frag->frag_dead = true; + up_write(&frag->frag_sem); + + inode_lock_nested(d_inode(root), I_MUTEX_PARENT); - mutex_lock_nested(&dentry->d_inode->i_mutex, I_MUTEX_CHILD); + inode_lock_nested(d_inode(dentry), I_MUTEX_CHILD); mutex_lock(&configfs_symlink_mutex); spin_lock(&configfs_dirent_lock); if (configfs_detach_prep(dentry, NULL)) { - printk(KERN_ERR "configfs: Tried to unregister non-empty subsystem!\n"); + pr_err("Tried to unregister non-empty subsystem!\n"); } spin_unlock(&configfs_dirent_lock); mutex_unlock(&configfs_symlink_mutex); configfs_detach_group(&group->cg_item); - dentry->d_inode->i_flags |= S_DEAD; + d_inode(dentry)->i_flags |= S_DEAD; dont_mount(dentry); - mutex_unlock(&dentry->d_inode->i_mutex); + inode_unlock(d_inode(dentry)); - d_delete(dentry); + d_drop(dentry); + fsnotify_rmdir(d_inode(root), dentry); - mutex_unlock(&root->d_inode->i_mutex); + inode_unlock(d_inode(root)); dput(dentry); + mutex_lock(&configfs_subsystem_mutex); unlink_group(group); + mutex_unlock(&configfs_subsystem_mutex); configfs_release_fs(); } diff --git a/fs/configfs/file.c b/fs/configfs/file.c index 1d1c41f1014d..affe4742bbb5 100644 --- a/fs/configfs/file.c +++ b/fs/configfs/file.c @@ -1,23 +1,7 @@ -/* -*- mode: c; c-basic-offset: 8; -*- - * vim: noexpandtab sw=8 ts=8 sts=0: - * +// SPDX-License-Identifier: GPL-2.0-or-later +/* * file.c - operations for regular (text) files. * - * This program is free software; you can redistribute it and/or - * modify it under the terms of the GNU General Public - * License as published by the Free Software Foundation; either - * version 2 of the License, or (at your option) any later version. - * - * This program is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - * General Public License for more details. - * - * You should have received a copy of the GNU General Public - * License along with this program; if not, write to the - * Free Software Foundation, Inc., 59 Temple Place - Suite 330, - * Boston, MA 021110-1307, USA. - * * Based on sysfs: * sysfs is Copyright (C) 2001, 2002, 2003 Patrick Mochel * @@ -28,8 +12,9 @@ #include <linux/module.h> #include <linux/slab.h> #include <linux/mutex.h> -#include <asm/uaccess.h> - +#include <linux/vmalloc.h> +#include <linux/uaccess.h> +#include <linux/uio.h> #include <linux/configfs.h> #include "configfs_internal.h" @@ -45,202 +30,320 @@ struct configfs_buffer { size_t count; loff_t pos; char * page; - struct configfs_item_operations * ops; + const struct configfs_item_operations *ops; struct mutex mutex; int needs_read_fill; + bool read_in_progress; + bool write_in_progress; + char *bin_buffer; + int bin_buffer_size; + int cb_max_size; + struct config_item *item; + struct module *owner; + union { + struct configfs_attribute *attr; + struct configfs_bin_attribute *bin_attr; + }; }; +static inline struct configfs_fragment *to_frag(struct file *file) +{ + struct configfs_dirent *sd = file->f_path.dentry->d_fsdata; -/** - * fill_read_buffer - allocate and fill buffer from item. - * @dentry: dentry pointer. - * @buffer: data buffer for file. - * - * Allocate @buffer->page, if it hasn't been already, then call the - * config_item's show() method to fill the buffer with this attribute's - * data. - * This is called only once, on the file's first read. - */ -static int fill_read_buffer(struct dentry * dentry, struct configfs_buffer * buffer) + return sd->s_frag; +} + +static int fill_read_buffer(struct file *file, struct configfs_buffer *buffer) { - struct configfs_attribute * attr = to_attr(dentry); - struct config_item * item = to_item(dentry->d_parent); - struct configfs_item_operations * ops = buffer->ops; - int ret = 0; - ssize_t count; + struct configfs_fragment *frag = to_frag(file); + ssize_t count = -ENOENT; if (!buffer->page) buffer->page = (char *) get_zeroed_page(GFP_KERNEL); if (!buffer->page) return -ENOMEM; - count = ops->show_attribute(item,attr,buffer->page); + down_read(&frag->frag_sem); + if (!frag->frag_dead) + count = buffer->attr->show(buffer->item, buffer->page); + up_read(&frag->frag_sem); + + if (count < 0) + return count; + if (WARN_ON_ONCE(count > (ssize_t)SIMPLE_ATTR_SIZE)) + return -EIO; buffer->needs_read_fill = 0; - BUG_ON(count > (ssize_t)SIMPLE_ATTR_SIZE); - if (count >= 0) - buffer->count = count; - else - ret = count; - return ret; + buffer->count = count; + return 0; } -/** - * configfs_read_file - read an attribute. - * @file: file pointer. - * @buf: buffer to fill. - * @count: number of bytes to read. - * @ppos: starting offset in file. - * - * Userspace wants to read an attribute file. The attribute descriptor - * is in the file's ->d_fsdata. The target item is in the directory's - * ->d_fsdata. - * - * We call fill_read_buffer() to allocate and fill the buffer from the - * item's show() method exactly once (if the read is happening from - * the beginning of the file). That should fill the entire buffer with - * all the data the item has to offer for that attribute. - * We then call flush_read_buffer() to copy the buffer to userspace - * in the increments specified. - */ - -static ssize_t -configfs_read_file(struct file *file, char __user *buf, size_t count, loff_t *ppos) +static ssize_t configfs_read_iter(struct kiocb *iocb, struct iov_iter *to) { - struct configfs_buffer * buffer = file->private_data; + struct file *file = iocb->ki_filp; + struct configfs_buffer *buffer = file->private_data; ssize_t retval = 0; mutex_lock(&buffer->mutex); if (buffer->needs_read_fill) { - if ((retval = fill_read_buffer(file->f_path.dentry,buffer))) + retval = fill_read_buffer(file, buffer); + if (retval) goto out; } - pr_debug("%s: count = %zd, ppos = %lld, buf = %s\n", - __func__, count, *ppos, buffer->page); - retval = simple_read_from_buffer(buf, count, ppos, buffer->page, - buffer->count); + pr_debug("%s: count = %zd, pos = %lld, buf = %s\n", + __func__, iov_iter_count(to), iocb->ki_pos, buffer->page); + if (iocb->ki_pos >= buffer->count) + goto out; + retval = copy_to_iter(buffer->page + iocb->ki_pos, + buffer->count - iocb->ki_pos, to); + iocb->ki_pos += retval; + if (retval == 0) + retval = -EFAULT; out: mutex_unlock(&buffer->mutex); return retval; } +static ssize_t configfs_bin_read_iter(struct kiocb *iocb, struct iov_iter *to) +{ + struct file *file = iocb->ki_filp; + struct configfs_fragment *frag = to_frag(file); + struct configfs_buffer *buffer = file->private_data; + ssize_t retval = 0; + ssize_t len; + + mutex_lock(&buffer->mutex); -/** - * fill_write_buffer - copy buffer from userspace. - * @buffer: data buffer for file. - * @buf: data from user. - * @count: number of bytes in @userbuf. - * - * Allocate @buffer->page if it hasn't been already, then - * copy the user-supplied buffer into it. - */ + /* we don't support switching read/write modes */ + if (buffer->write_in_progress) { + retval = -ETXTBSY; + goto out; + } + buffer->read_in_progress = true; -static int -fill_write_buffer(struct configfs_buffer * buffer, const char __user * buf, size_t count) + if (buffer->needs_read_fill) { + /* perform first read with buf == NULL to get extent */ + down_read(&frag->frag_sem); + if (!frag->frag_dead) + len = buffer->bin_attr->read(buffer->item, NULL, 0); + else + len = -ENOENT; + up_read(&frag->frag_sem); + if (len <= 0) { + retval = len; + goto out; + } + + /* do not exceed the maximum value */ + if (buffer->cb_max_size && len > buffer->cb_max_size) { + retval = -EFBIG; + goto out; + } + + buffer->bin_buffer = vmalloc(len); + if (buffer->bin_buffer == NULL) { + retval = -ENOMEM; + goto out; + } + buffer->bin_buffer_size = len; + + /* perform second read to fill buffer */ + down_read(&frag->frag_sem); + if (!frag->frag_dead) + len = buffer->bin_attr->read(buffer->item, + buffer->bin_buffer, len); + else + len = -ENOENT; + up_read(&frag->frag_sem); + if (len < 0) { + retval = len; + vfree(buffer->bin_buffer); + buffer->bin_buffer_size = 0; + buffer->bin_buffer = NULL; + goto out; + } + + buffer->needs_read_fill = 0; + } + + if (iocb->ki_pos >= buffer->bin_buffer_size) + goto out; + retval = copy_to_iter(buffer->bin_buffer + iocb->ki_pos, + buffer->bin_buffer_size - iocb->ki_pos, to); + iocb->ki_pos += retval; + if (retval == 0) + retval = -EFAULT; +out: + mutex_unlock(&buffer->mutex); + return retval; +} + +/* Fill @buffer with data coming from @from. */ +static int fill_write_buffer(struct configfs_buffer *buffer, + struct iov_iter *from) { - int error; + int copied; if (!buffer->page) buffer->page = (char *)__get_free_pages(GFP_KERNEL, 0); if (!buffer->page) return -ENOMEM; - if (count >= SIMPLE_ATTR_SIZE) - count = SIMPLE_ATTR_SIZE - 1; - error = copy_from_user(buffer->page,buf,count); + copied = copy_from_iter(buffer->page, SIMPLE_ATTR_SIZE - 1, from); buffer->needs_read_fill = 1; /* if buf is assumed to contain a string, terminate it by \0, * so e.g. sscanf() can scan the string easily */ - buffer->page[count] = 0; - return error ? -EFAULT : count; + buffer->page[copied] = 0; + return copied ? : -EFAULT; } - -/** - * flush_write_buffer - push buffer to config_item. - * @dentry: dentry to the attribute - * @buffer: data buffer for file. - * @count: number of bytes - * - * Get the correct pointers for the config_item and the attribute we're - * dealing with, then call the store() method for the attribute, - * passing the buffer that we acquired in fill_write_buffer(). - */ - static int -flush_write_buffer(struct dentry * dentry, struct configfs_buffer * buffer, size_t count) +flush_write_buffer(struct file *file, struct configfs_buffer *buffer, size_t count) { - struct configfs_attribute * attr = to_attr(dentry); - struct config_item * item = to_item(dentry->d_parent); - struct configfs_item_operations * ops = buffer->ops; - - return ops->store_attribute(item,attr,buffer->page,count); + struct configfs_fragment *frag = to_frag(file); + int res = -ENOENT; + + down_read(&frag->frag_sem); + if (!frag->frag_dead) + res = buffer->attr->store(buffer->item, buffer->page, count); + up_read(&frag->frag_sem); + return res; } -/** - * configfs_write_file - write an attribute. - * @file: file pointer - * @buf: data to write - * @count: number of bytes - * @ppos: starting offset - * - * Similar to configfs_read_file(), though working in the opposite direction. - * We allocate and fill the data from the user in fill_write_buffer(), - * then push it to the config_item in flush_write_buffer(). - * There is no easy way for us to know if userspace is only doing a partial - * write, so we don't support them. We expect the entire buffer to come - * on the first write. - * Hint: if you're writing a value, first read the file, modify only the - * the value you're changing, then write entire buffer back. +/* + * There is no easy way for us to know if userspace is only doing a partial + * write, so we don't support them. We expect the entire buffer to come on the + * first write. + * Hint: if you're writing a value, first read the file, modify only the value + * you're changing, then write entire buffer back. */ - -static ssize_t -configfs_write_file(struct file *file, const char __user *buf, size_t count, loff_t *ppos) +static ssize_t configfs_write_iter(struct kiocb *iocb, struct iov_iter *from) { - struct configfs_buffer * buffer = file->private_data; - ssize_t len; + struct file *file = iocb->ki_filp; + struct configfs_buffer *buffer = file->private_data; + int len; mutex_lock(&buffer->mutex); - len = fill_write_buffer(buffer, buf, count); + len = fill_write_buffer(buffer, from); if (len > 0) - len = flush_write_buffer(file->f_path.dentry, buffer, len); + len = flush_write_buffer(file, buffer, len); if (len > 0) - *ppos += len; + iocb->ki_pos += len; mutex_unlock(&buffer->mutex); return len; } -static int check_perm(struct inode * inode, struct file * file) +static ssize_t configfs_bin_write_iter(struct kiocb *iocb, + struct iov_iter *from) { - struct config_item *item = configfs_get_config_item(file->f_path.dentry->d_parent); - struct configfs_attribute * attr = to_attr(file->f_path.dentry); - struct configfs_buffer * buffer; - struct configfs_item_operations * ops = NULL; - int error = 0; + struct file *file = iocb->ki_filp; + struct configfs_buffer *buffer = file->private_data; + void *tbuf = NULL; + size_t end_offset; + ssize_t len; - if (!item || !attr) - goto Einval; + mutex_lock(&buffer->mutex); - /* Grab the module reference for this attribute if we have one */ - if (!try_module_get(attr->ca_owner)) { - error = -ENODEV; - goto Done; + /* we don't support switching read/write modes */ + if (buffer->read_in_progress) { + len = -ETXTBSY; + goto out; + } + buffer->write_in_progress = true; + + /* buffer grows? */ + end_offset = iocb->ki_pos + iov_iter_count(from); + if (end_offset > buffer->bin_buffer_size) { + if (buffer->cb_max_size && end_offset > buffer->cb_max_size) { + len = -EFBIG; + goto out; + } + + tbuf = vmalloc(end_offset); + if (tbuf == NULL) { + len = -ENOMEM; + goto out; + } + + /* copy old contents */ + if (buffer->bin_buffer) { + memcpy(tbuf, buffer->bin_buffer, + buffer->bin_buffer_size); + vfree(buffer->bin_buffer); + } + + /* clear the new area */ + memset(tbuf + buffer->bin_buffer_size, 0, + end_offset - buffer->bin_buffer_size); + buffer->bin_buffer = tbuf; + buffer->bin_buffer_size = end_offset; } - if (item->ci_type) - ops = item->ci_type->ct_item_ops; - else - goto Eaccess; + len = copy_from_iter(buffer->bin_buffer + iocb->ki_pos, + buffer->bin_buffer_size - iocb->ki_pos, from); + iocb->ki_pos += len; +out: + mutex_unlock(&buffer->mutex); + return len ? : -EFAULT; +} + +static int __configfs_open_file(struct inode *inode, struct file *file, int type) +{ + struct dentry *dentry = file->f_path.dentry; + struct configfs_fragment *frag = to_frag(file); + struct configfs_attribute *attr; + struct configfs_buffer *buffer; + int error; + + error = -ENOMEM; + buffer = kzalloc(sizeof(struct configfs_buffer), GFP_KERNEL); + if (!buffer) + goto out; + + error = -ENOENT; + down_read(&frag->frag_sem); + if (unlikely(frag->frag_dead)) + goto out_free_buffer; + + error = -EINVAL; + buffer->item = to_item(dentry->d_parent); + if (!buffer->item) + goto out_free_buffer; + + attr = to_attr(dentry); + if (!attr) + goto out_free_buffer; + + if (type & CONFIGFS_ITEM_BIN_ATTR) { + buffer->bin_attr = to_bin_attr(dentry); + buffer->cb_max_size = buffer->bin_attr->cb_max_size; + } else { + buffer->attr = attr; + } + + buffer->owner = attr->ca_owner; + /* Grab the module reference for this attribute if we have one */ + error = -ENODEV; + if (!try_module_get(buffer->owner)) + goto out_free_buffer; + + error = -EACCES; + if (!buffer->item->ci_type) + goto out_put_module; + + buffer->ops = buffer->item->ci_type->ct_item_ops; /* File needs write support. * The inode's perms must say it's ok, * and we must have a store method. */ if (file->f_mode & FMODE_WRITE) { - - if (!(inode->i_mode & S_IWUGO) || !ops->store_attribute) - goto Eaccess; - + if (!(inode->i_mode & S_IWUGO)) + goto out_put_module; + if ((type & CONFIGFS_ITEM_ATTR) && !attr->store) + goto out_put_module; + if ((type & CONFIGFS_ITEM_BIN_ATTR) && !buffer->bin_attr->write) + goto out_put_module; } /* File needs read support. @@ -248,97 +351,132 @@ static int check_perm(struct inode * inode, struct file * file) * must be a show method for it. */ if (file->f_mode & FMODE_READ) { - if (!(inode->i_mode & S_IRUGO) || !ops->show_attribute) - goto Eaccess; + if (!(inode->i_mode & S_IRUGO)) + goto out_put_module; + if ((type & CONFIGFS_ITEM_ATTR) && !attr->show) + goto out_put_module; + if ((type & CONFIGFS_ITEM_BIN_ATTR) && !buffer->bin_attr->read) + goto out_put_module; } - /* No error? Great, allocate a buffer for the file, and store it - * it in file->private_data for easy access. - */ - buffer = kzalloc(sizeof(struct configfs_buffer),GFP_KERNEL); - if (!buffer) { - error = -ENOMEM; - goto Enomem; - } mutex_init(&buffer->mutex); buffer->needs_read_fill = 1; - buffer->ops = ops; + buffer->read_in_progress = false; + buffer->write_in_progress = false; file->private_data = buffer; - goto Done; + up_read(&frag->frag_sem); + return 0; - Einval: - error = -EINVAL; - goto Done; - Eaccess: - error = -EACCES; - Enomem: - module_put(attr->ca_owner); - Done: - if (error && item) - config_item_put(item); +out_put_module: + module_put(buffer->owner); +out_free_buffer: + up_read(&frag->frag_sem); + kfree(buffer); +out: return error; } -static int configfs_open_file(struct inode * inode, struct file * filp) +static int configfs_release(struct inode *inode, struct file *filp) +{ + struct configfs_buffer *buffer = filp->private_data; + + module_put(buffer->owner); + if (buffer->page) + free_page((unsigned long)buffer->page); + mutex_destroy(&buffer->mutex); + kfree(buffer); + return 0; +} + +static int configfs_open_file(struct inode *inode, struct file *filp) { - return check_perm(inode,filp); + return __configfs_open_file(inode, filp, CONFIGFS_ITEM_ATTR); } -static int configfs_release(struct inode * inode, struct file * filp) +static int configfs_open_bin_file(struct inode *inode, struct file *filp) { - struct config_item * item = to_item(filp->f_path.dentry->d_parent); - struct configfs_attribute * attr = to_attr(filp->f_path.dentry); - struct module * owner = attr->ca_owner; - struct configfs_buffer * buffer = filp->private_data; - - if (item) - config_item_put(item); - /* After this point, attr should not be accessed. */ - module_put(owner); - - if (buffer) { - if (buffer->page) - free_page((unsigned long)buffer->page); - mutex_destroy(&buffer->mutex); - kfree(buffer); + return __configfs_open_file(inode, filp, CONFIGFS_ITEM_BIN_ATTR); +} + +static int configfs_release_bin_file(struct inode *inode, struct file *file) +{ + struct configfs_buffer *buffer = file->private_data; + + if (buffer->write_in_progress) { + struct configfs_fragment *frag = to_frag(file); + + down_read(&frag->frag_sem); + if (!frag->frag_dead) { + /* result of ->release() is ignored */ + buffer->bin_attr->write(buffer->item, + buffer->bin_buffer, + buffer->bin_buffer_size); + } + up_read(&frag->frag_sem); } + + vfree(buffer->bin_buffer); + + configfs_release(inode, file); return 0; } + const struct file_operations configfs_file_operations = { - .read = configfs_read_file, - .write = configfs_write_file, + .read_iter = configfs_read_iter, + .write_iter = configfs_write_iter, .llseek = generic_file_llseek, .open = configfs_open_file, .release = configfs_release, }; +const struct file_operations configfs_bin_file_operations = { + .read_iter = configfs_bin_read_iter, + .write_iter = configfs_bin_write_iter, + .llseek = NULL, /* bin file is not seekable */ + .open = configfs_open_bin_file, + .release = configfs_release_bin_file, +}; -int configfs_add_file(struct dentry * dir, const struct configfs_attribute * attr, int type) +/** + * configfs_create_file - create an attribute file for an item. + * @item: item we're creating for. + * @attr: atrribute descriptor. + */ + +int configfs_create_file(struct config_item * item, const struct configfs_attribute * attr) { - struct configfs_dirent * parent_sd = dir->d_fsdata; + struct dentry *dir = item->ci_dentry; + struct configfs_dirent *parent_sd = dir->d_fsdata; umode_t mode = (attr->ca_mode & S_IALLUGO) | S_IFREG; int error = 0; - mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_NORMAL); - error = configfs_make_dirent(parent_sd, NULL, (void *) attr, mode, type); - mutex_unlock(&dir->d_inode->i_mutex); + inode_lock_nested(d_inode(dir), I_MUTEX_NORMAL); + error = configfs_make_dirent(parent_sd, NULL, (void *) attr, mode, + CONFIGFS_ITEM_ATTR, parent_sd->s_frag); + inode_unlock(d_inode(dir)); return error; } - /** - * configfs_create_file - create an attribute file for an item. + * configfs_create_bin_file - create a binary attribute file for an item. * @item: item we're creating for. - * @attr: atrribute descriptor. + * @bin_attr: atrribute descriptor. */ -int configfs_create_file(struct config_item * item, const struct configfs_attribute * attr) +int configfs_create_bin_file(struct config_item *item, + const struct configfs_bin_attribute *bin_attr) { - BUG_ON(!item || !item->ci_dentry || !attr); + struct dentry *dir = item->ci_dentry; + struct configfs_dirent *parent_sd = dir->d_fsdata; + umode_t mode = (bin_attr->cb_attr.ca_mode & S_IALLUGO) | S_IFREG; + int error = 0; - return configfs_add_file(item->ci_dentry, attr, - CONFIGFS_ITEM_ATTR); -} + inode_lock_nested(dir->d_inode, I_MUTEX_NORMAL); + error = configfs_make_dirent(parent_sd, NULL, (void *) bin_attr, mode, + CONFIGFS_ITEM_BIN_ATTR, parent_sd->s_frag); + inode_unlock(dir->d_inode); + return error; +} diff --git a/fs/configfs/inode.c b/fs/configfs/inode.c index a9d35b0e06cf..bcda3372e141 100644 --- a/fs/configfs/inode.c +++ b/fs/configfs/inode.c @@ -1,29 +1,13 @@ -/* -*- mode: c; c-basic-offset: 8; -*- - * vim: noexpandtab sw=8 ts=8 sts=0: - * +// SPDX-License-Identifier: GPL-2.0-or-later +/* * inode.c - basic inode and dentry operations. * - * This program is free software; you can redistribute it and/or - * modify it under the terms of the GNU General Public - * License as published by the Free Software Foundation; either - * version 2 of the License, or (at your option) any later version. - * - * This program is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - * General Public License for more details. - * - * You should have received a copy of the GNU General Public - * License along with this program; if not, write to the - * Free Software Foundation, Inc., 59 Temple Place - Suite 330, - * Boston, MA 021110-1307, USA. - * * Based on sysfs: * sysfs is Copyright (C) 2001, 2002, 2003 Patrick Mochel * * configfs Copyright (C) 2005 Oracle. All rights reserved. * - * Please see Documentation/filesystems/configfs/configfs.txt for more + * Please see Documentation/filesystems/configfs.rst for more * information. */ @@ -44,25 +28,14 @@ static struct lock_class_key default_group_class[MAX_LOCK_DEPTH]; #endif -static const struct address_space_operations configfs_aops = { - .readpage = simple_readpage, - .write_begin = simple_write_begin, - .write_end = simple_write_end, -}; - -static struct backing_dev_info configfs_backing_dev_info = { - .name = "configfs", - .ra_pages = 0, /* No readahead */ - .capabilities = BDI_CAP_NO_ACCT_AND_WRITEBACK, -}; - static const struct inode_operations configfs_inode_operations ={ .setattr = configfs_setattr, }; -int configfs_setattr(struct dentry * dentry, struct iattr * iattr) +int configfs_setattr(struct mnt_idmap *idmap, struct dentry *dentry, + struct iattr *iattr) { - struct inode * inode = dentry->d_inode; + struct inode * inode = d_inode(dentry); struct configfs_dirent * sd = dentry->d_fsdata; struct iattr * sd_iattr; unsigned int ia_valid = iattr->ia_valid; @@ -81,12 +54,13 @@ int configfs_setattr(struct dentry * dentry, struct iattr * iattr) sd_iattr->ia_mode = sd->s_mode; sd_iattr->ia_uid = GLOBAL_ROOT_UID; sd_iattr->ia_gid = GLOBAL_ROOT_GID; - sd_iattr->ia_atime = sd_iattr->ia_mtime = sd_iattr->ia_ctime = CURRENT_TIME; + sd_iattr->ia_atime = sd_iattr->ia_mtime = + sd_iattr->ia_ctime = current_time(inode); sd->s_iattr = sd_iattr; } /* attributes were changed atleast once in past */ - error = simple_setattr(dentry, iattr); + error = simple_setattr(idmap, dentry, iattr); if (error) return error; @@ -95,14 +69,11 @@ int configfs_setattr(struct dentry * dentry, struct iattr * iattr) if (ia_valid & ATTR_GID) sd_iattr->ia_gid = iattr->ia_gid; if (ia_valid & ATTR_ATIME) - sd_iattr->ia_atime = timespec_trunc(iattr->ia_atime, - inode->i_sb->s_time_gran); + sd_iattr->ia_atime = iattr->ia_atime; if (ia_valid & ATTR_MTIME) - sd_iattr->ia_mtime = timespec_trunc(iattr->ia_mtime, - inode->i_sb->s_time_gran); + sd_iattr->ia_mtime = iattr->ia_mtime; if (ia_valid & ATTR_CTIME) - sd_iattr->ia_ctime = timespec_trunc(iattr->ia_ctime, - inode->i_sb->s_time_gran); + sd_iattr->ia_ctime = iattr->ia_ctime; if (ia_valid & ATTR_MODE) { umode_t mode = iattr->ia_mode; @@ -117,7 +88,7 @@ int configfs_setattr(struct dentry * dentry, struct iattr * iattr) static inline void set_default_inode_attr(struct inode * inode, umode_t mode) { inode->i_mode = mode; - inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; + simple_inode_init_ts(inode); } static inline void set_inode_attr(struct inode * inode, struct iattr * iattr) @@ -125,9 +96,9 @@ static inline void set_inode_attr(struct inode * inode, struct iattr * iattr) inode->i_mode = iattr->ia_mode; inode->i_uid = iattr->ia_uid; inode->i_gid = iattr->ia_gid; - inode->i_atime = iattr->ia_atime; - inode->i_mtime = iattr->ia_mtime; - inode->i_ctime = iattr->ia_ctime; + inode_set_atime_to_ts(inode, iattr->ia_atime); + inode_set_mtime_to_ts(inode, iattr->ia_mtime); + inode_set_ctime_to_ts(inode, iattr->ia_ctime); } struct inode *configfs_new_inode(umode_t mode, struct configfs_dirent *sd, @@ -136,8 +107,7 @@ struct inode *configfs_new_inode(umode_t mode, struct configfs_dirent *sd, struct inode * inode = new_inode(s); if (inode) { inode->i_ino = get_next_ino(); - inode->i_mapping->a_ops = &configfs_aops; - inode->i_mapping->backing_dev_info = &configfs_backing_dev_info; + inode->i_mapping->a_ops = &ram_aops; inode->i_op = &configfs_inode_operations; if (sd->s_iattr) { @@ -161,16 +131,15 @@ static void configfs_set_inode_lock_class(struct configfs_dirent *sd, if (depth > 0) { if (depth <= ARRAY_SIZE(default_group_class)) { - lockdep_set_class(&inode->i_mutex, + lockdep_set_class(&inode->i_rwsem, &default_group_class[depth - 1]); } else { /* * In practice the maximum level of locking depth is * already reached. Just inform about possible reasons. */ - printk(KERN_INFO "configfs: Too many levels of inodes" - " for the locking correctness validator.\n"); - printk(KERN_INFO "Spurious warnings may appear.\n"); + pr_info("Too many levels of inodes for the locking correctness validator.\n"); + pr_info("Spurious warnings may appear.\n"); } } } @@ -184,39 +153,27 @@ static void configfs_set_inode_lock_class(struct configfs_dirent *sd, #endif /* CONFIG_LOCKDEP */ -int configfs_create(struct dentry * dentry, umode_t mode, int (*init)(struct inode *)) +struct inode *configfs_create(struct dentry *dentry, umode_t mode) { - int error = 0; struct inode *inode = NULL; struct configfs_dirent *sd; struct inode *p_inode; if (!dentry) - return -ENOENT; + return ERR_PTR(-ENOENT); - if (dentry->d_inode) - return -EEXIST; + if (d_really_is_positive(dentry)) + return ERR_PTR(-EEXIST); sd = dentry->d_fsdata; inode = configfs_new_inode(mode, sd, dentry->d_sb); if (!inode) - return -ENOMEM; + return ERR_PTR(-ENOMEM); - p_inode = dentry->d_parent->d_inode; - p_inode->i_mtime = p_inode->i_ctime = CURRENT_TIME; + p_inode = d_inode(dentry->d_parent); + inode_set_mtime_to_ts(p_inode, inode_set_ctime_current(p_inode)); configfs_set_inode_lock_class(sd, inode); - - if (init) { - error = init(inode); - if (error) { - iput(inode); - return error; - } - } - d_instantiate(dentry, inode); - if (S_ISDIR(mode) || S_ISLNK(mode)) - dget(dentry); /* pin link and directory dentries in core */ - return error; + return inode; } /* @@ -232,7 +189,7 @@ const unsigned char * configfs_get_name(struct configfs_dirent *sd) if (sd->s_type & (CONFIGFS_DIR | CONFIGFS_ITEM_LINK)) return sd->s_dentry->d_name.name; - if (sd->s_type & CONFIGFS_ITEM_ATTR) { + if (sd->s_type & (CONFIGFS_ITEM_ATTR | CONFIGFS_ITEM_BIN_ATTR)) { attr = sd->s_element; return attr->ca_name; } @@ -250,47 +207,13 @@ void configfs_drop_dentry(struct configfs_dirent * sd, struct dentry * parent) if (dentry) { spin_lock(&dentry->d_lock); - if (!(d_unhashed(dentry) && dentry->d_inode)) { + if (simple_positive(dentry)) { dget_dlock(dentry); __d_drop(dentry); spin_unlock(&dentry->d_lock); - simple_unlink(parent->d_inode, dentry); + __simple_unlink(d_inode(parent), dentry); + dput(dentry); } else spin_unlock(&dentry->d_lock); } } - -void configfs_hash_and_remove(struct dentry * dir, const char * name) -{ - struct configfs_dirent * sd; - struct configfs_dirent * parent_sd = dir->d_fsdata; - - if (dir->d_inode == NULL) - /* no inode means this hasn't been made visible yet */ - return; - - mutex_lock(&dir->d_inode->i_mutex); - list_for_each_entry(sd, &parent_sd->s_children, s_sibling) { - if (!sd->s_element) - continue; - if (!strcmp(configfs_get_name(sd), name)) { - spin_lock(&configfs_dirent_lock); - list_del_init(&sd->s_sibling); - spin_unlock(&configfs_dirent_lock); - configfs_drop_dentry(sd, dir); - configfs_put(sd); - break; - } - } - mutex_unlock(&dir->d_inode->i_mutex); -} - -int __init configfs_inode_init(void) -{ - return bdi_init(&configfs_backing_dev_info); -} - -void configfs_inode_exit(void) -{ - bdi_destroy(&configfs_backing_dev_info); -} diff --git a/fs/configfs/item.c b/fs/configfs/item.c index 50cee7f9110b..c378b5cbf87d 100644 --- a/fs/configfs/item.c +++ b/fs/configfs/item.c @@ -1,29 +1,13 @@ -/* -*- mode: c; c-basic-offset: 8; -*- - * vim: noexpandtab sw=8 ts=8 sts=0: - * +// SPDX-License-Identifier: GPL-2.0-or-later +/* * item.c - library routines for handling generic config items * - * This program is free software; you can redistribute it and/or - * modify it under the terms of the GNU General Public - * License as published by the Free Software Foundation; either - * version 2 of the License, or (at your option) any later version. - * - * This program is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - * General Public License for more details. - * - * You should have received a copy of the GNU General Public - * License along with this program; if not, write to the - * Free Software Foundation, Inc., 59 Temple Place - Suite 330, - * Boston, MA 021110-1307, USA. - * * Based on kobject: - * kobject is Copyright (c) 2002-2003 Patrick Mochel + * kobject is Copyright (c) 2002-2003 Patrick Mochel * * configfs Copyright (C) 2005 Oracle. All rights reserved. * - * Please see the file Documentation/filesystems/configfs/configfs.txt for + * Please see the file Documentation/filesystems/configfs.rst for * critical information about using the config_item interface. */ @@ -35,9 +19,9 @@ #include <linux/configfs.h> -static inline struct config_item * to_item(struct list_head * entry) +static inline struct config_item *to_item(struct list_head *entry) { - return container_of(entry,struct config_item,ci_entry); + return container_of(entry, struct config_item, ci_entry); } /* Evil kernel */ @@ -47,7 +31,7 @@ static void config_item_release(struct kref *kref); * config_item_init - initialize item. * @item: item in question. */ -void config_item_init(struct config_item * item) +static void config_item_init(struct config_item *item) { kref_init(&item->ci_kref); INIT_LIST_HEAD(&item->ci_entry); @@ -56,48 +40,33 @@ void config_item_init(struct config_item * item) /** * config_item_set_name - Set the name of an item * @item: item. - * @name: name. + * @fmt: The vsnprintf()'s format string. * * If strlen(name) >= CONFIGFS_ITEM_NAME_LEN, then use a * dynamically allocated string that @item->ci_name points to. * Otherwise, use the static @item->ci_namebuf array. */ -int config_item_set_name(struct config_item * item, const char * fmt, ...) +int config_item_set_name(struct config_item *item, const char *fmt, ...) { - int error = 0; int limit = CONFIGFS_ITEM_NAME_LEN; int need; va_list args; - char * name; + char *name; /* * First, try the static array */ - va_start(args,fmt); - need = vsnprintf(item->ci_namebuf,limit,fmt,args); + va_start(args, fmt); + need = vsnprintf(item->ci_namebuf, limit, fmt, args); va_end(args); if (need < limit) name = item->ci_namebuf; else { - /* - * Need more space? Allocate it and try again - */ - limit = need + 1; - name = kmalloc(limit,GFP_KERNEL); - if (!name) { - error = -ENOMEM; - goto Done; - } - va_start(args,fmt); - need = vsnprintf(name,limit,fmt,args); + va_start(args, fmt); + name = kvasprintf(GFP_KERNEL, fmt, args); va_end(args); - - /* Still? Give up. */ - if (need >= limit) { - kfree(name); - error = -EFAULT; - goto Done; - } + if (!name) + return -ENOMEM; } /* Free the old name, if necessary. */ @@ -106,45 +75,52 @@ int config_item_set_name(struct config_item * item, const char * fmt, ...) /* Now, set the new name */ item->ci_name = name; - Done: - return error; + return 0; } - EXPORT_SYMBOL(config_item_set_name); void config_item_init_type_name(struct config_item *item, const char *name, - struct config_item_type *type) + const struct config_item_type *type) { - config_item_set_name(item, name); + config_item_set_name(item, "%s", name); item->ci_type = type; config_item_init(item); } EXPORT_SYMBOL(config_item_init_type_name); void config_group_init_type_name(struct config_group *group, const char *name, - struct config_item_type *type) + const struct config_item_type *type) { - config_item_set_name(&group->cg_item, name); + config_item_set_name(&group->cg_item, "%s", name); group->cg_item.ci_type = type; config_group_init(group); } EXPORT_SYMBOL(config_group_init_type_name); -struct config_item * config_item_get(struct config_item * item) +struct config_item *config_item_get(struct config_item *item) { if (item) kref_get(&item->ci_kref); return item; } +EXPORT_SYMBOL(config_item_get); + +struct config_item *config_item_get_unless_zero(struct config_item *item) +{ + if (item && kref_get_unless_zero(&item->ci_kref)) + return item; + return NULL; +} +EXPORT_SYMBOL(config_item_get_unless_zero); -static void config_item_cleanup(struct config_item * item) +static void config_item_cleanup(struct config_item *item) { - struct config_item_type * t = item->ci_type; - struct config_group * s = item->ci_group; - struct config_item * parent = item->ci_parent; + const struct config_item_type *t = item->ci_type; + struct config_group *s = item->ci_group; + struct config_item *parent = item->ci_parent; - pr_debug("config_item %s: cleaning up\n",config_item_name(item)); + pr_debug("config_item %s: cleaning up\n", config_item_name(item)); if (item->ci_name != item->ci_namebuf) kfree(item->ci_name); item->ci_name = NULL; @@ -167,21 +143,24 @@ static void config_item_release(struct kref *kref) * * Decrement the refcount, and if 0, call config_item_cleanup(). */ -void config_item_put(struct config_item * item) +void config_item_put(struct config_item *item) { if (item) kref_put(&item->ci_kref, config_item_release); } +EXPORT_SYMBOL(config_item_put); /** * config_group_init - initialize a group for use - * @k: group + * @group: config_group */ void config_group_init(struct config_group *group) { config_item_init(&group->cg_item); INIT_LIST_HEAD(&group->cg_children); + INIT_LIST_HEAD(&group->default_groups); } +EXPORT_SYMBOL(config_group_init); /** * config_group_find_item - search for item in group. @@ -195,11 +174,11 @@ void config_group_init(struct config_group *group) struct config_item *config_group_find_item(struct config_group *group, const char *name) { - struct list_head * entry; - struct config_item * ret = NULL; + struct list_head *entry; + struct config_item *ret = NULL; - list_for_each(entry,&group->cg_children) { - struct config_item * item = to_item(entry); + list_for_each(entry, &group->cg_children) { + struct config_item *item = to_item(entry); if (config_item_name(item) && !strcmp(config_item_name(item), name)) { ret = config_item_get(item); @@ -208,9 +187,4 @@ struct config_item *config_group_find_item(struct config_group *group, } return ret; } - -EXPORT_SYMBOL(config_item_init); -EXPORT_SYMBOL(config_group_init); -EXPORT_SYMBOL(config_item_get); -EXPORT_SYMBOL(config_item_put); EXPORT_SYMBOL(config_group_find_item); diff --git a/fs/configfs/mount.c b/fs/configfs/mount.c index 7f26c3cf75ae..4929f3431189 100644 --- a/fs/configfs/mount.c +++ b/fs/configfs/mount.c @@ -1,23 +1,7 @@ -/* -*- mode: c; c-basic-offset: 8; -*- - * vim: noexpandtab sw=8 ts=8 sts=0: - * +// SPDX-License-Identifier: GPL-2.0-or-later +/* * mount.c - operations for initializing and mounting configfs. * - * This program is free software; you can redistribute it and/or - * modify it under the terms of the GNU General Public - * License as published by the Free Software Foundation; either - * version 2 of the License, or (at your option) any later version. - * - * This program is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - * General Public License for more details. - * - * You should have received a copy of the GNU General Public - * License along with this program; if not, write to the - * Free Software Foundation, Inc., 59 Temple Place - Suite 330, - * Boston, MA 021110-1307, USA. - * * Based on sysfs: * sysfs is Copyright (C) 2001, 2002, 2003 Patrick Mochel * @@ -27,6 +11,7 @@ #include <linux/fs.h> #include <linux/module.h> #include <linux/mount.h> +#include <linux/fs_context.h> #include <linux/pagemap.h> #include <linux/init.h> #include <linux/slab.h> @@ -41,9 +26,18 @@ static struct vfsmount *configfs_mount = NULL; struct kmem_cache *configfs_dir_cachep; static int configfs_mnt_count = 0; + +static void configfs_free_inode(struct inode *inode) +{ + if (S_ISLNK(inode->i_mode)) + kfree(inode->i_link); + free_inode_nonrcu(inode); +} + static const struct super_operations configfs_ops = { .statfs = simple_statfs, - .drop_inode = generic_delete_inode, + .drop_inode = inode_just_drop, + .free_inode = configfs_free_inode, }; static struct config_group configfs_root_group = { @@ -66,13 +60,13 @@ static struct configfs_dirent configfs_root = { .s_iattr = NULL, }; -static int configfs_fill_super(struct super_block *sb, void *data, int silent) +static int configfs_fill_super(struct super_block *sb, struct fs_context *fc) { struct inode *inode; struct dentry *root; - sb->s_blocksize = PAGE_CACHE_SIZE; - sb->s_blocksize_bits = PAGE_CACHE_SHIFT; + sb->s_blocksize = PAGE_SIZE; + sb->s_blocksize_bits = PAGE_SHIFT; sb->s_magic = CONFIGFS_MAGIC; sb->s_op = &configfs_ops; sb->s_time_gran = 1; @@ -85,7 +79,7 @@ static int configfs_fill_super(struct super_block *sb, void *data, int silent) /* directory inodes start off with i_nlink == 2 (for "." entry) */ inc_nlink(inode); } else { - pr_debug("configfs: could not get root inode\n"); + pr_debug("could not get root inode\n"); return -ENOMEM; } @@ -98,21 +92,31 @@ static int configfs_fill_super(struct super_block *sb, void *data, int silent) configfs_root_group.cg_item.ci_dentry = root; root->d_fsdata = &configfs_root; sb->s_root = root; - sb->s_d_op = &configfs_dentry_ops; /* the rest get that */ + set_default_d_op(sb, &configfs_dentry_ops); /* the rest get that */ + sb->s_d_flags |= DCACHE_DONTCACHE; return 0; } -static struct dentry *configfs_do_mount(struct file_system_type *fs_type, - int flags, const char *dev_name, void *data) +static int configfs_get_tree(struct fs_context *fc) +{ + return get_tree_single(fc, configfs_fill_super); +} + +static const struct fs_context_operations configfs_context_ops = { + .get_tree = configfs_get_tree, +}; + +static int configfs_init_fs_context(struct fs_context *fc) { - return mount_single(fs_type, flags, data, configfs_fill_super); + fc->ops = &configfs_context_ops; + return 0; } static struct file_system_type configfs_fs_type = { .owner = THIS_MODULE, .name = "configfs", - .mount = configfs_do_mount, - .kill_sb = kill_litter_super, + .init_fs_context = configfs_init_fs_context, + .kill_sb = kill_anon_super, }; MODULE_ALIAS_FS("configfs"); @@ -129,8 +133,6 @@ void configfs_release_fs(void) } -static struct kobject *config_kobj; - static int __init configfs_init(void) { int err = -ENOMEM; @@ -141,24 +143,18 @@ static int __init configfs_init(void) if (!configfs_dir_cachep) goto out; - config_kobj = kobject_create_and_add("config", kernel_kobj); - if (!config_kobj) - goto out2; - - err = configfs_inode_init(); + err = sysfs_create_mount_point(kernel_kobj, "config"); if (err) - goto out3; + goto out2; err = register_filesystem(&configfs_fs_type); if (err) - goto out4; + goto out3; return 0; -out4: - printk(KERN_ERR "configfs: Unable to register filesystem!\n"); - configfs_inode_exit(); out3: - kobject_put(config_kobj); + pr_err("Unable to register filesystem!\n"); + sysfs_remove_mount_point(kernel_kobj, "config"); out2: kmem_cache_destroy(configfs_dir_cachep); configfs_dir_cachep = NULL; @@ -169,10 +165,9 @@ out: static void __exit configfs_exit(void) { unregister_filesystem(&configfs_fs_type); - kobject_put(config_kobj); + sysfs_remove_mount_point(kernel_kobj, "config"); kmem_cache_destroy(configfs_dir_cachep); configfs_dir_cachep = NULL; - configfs_inode_exit(); } MODULE_AUTHOR("Oracle"); @@ -180,5 +175,5 @@ MODULE_LICENSE("GPL"); MODULE_VERSION("0.0.2"); MODULE_DESCRIPTION("Simple RAM filesystem for user driven kernel subsystem configuration."); -module_init(configfs_init); +core_initcall(configfs_init); module_exit(configfs_exit); diff --git a/fs/configfs/symlink.c b/fs/configfs/symlink.c index cc9f2546ea4a..f3f79c67add5 100644 --- a/fs/configfs/symlink.c +++ b/fs/configfs/symlink.c @@ -1,23 +1,7 @@ -/* -*- mode: c; c-basic-offset: 8; -*- - * vim: noexpandtab sw=8 ts=8 sts=0: - * +// SPDX-License-Identifier: GPL-2.0-or-later +/* * symlink.c - operations for configfs symlinks. * - * This program is free software; you can redistribute it and/or - * modify it under the terms of the GNU General Public - * License as published by the Free Software Foundation; either - * version 2 of the License, or (at your option) any later version. - * - * This program is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - * General Public License for more details. - * - * You should have received a copy of the GNU General Public - * License along with this program; if not, write to the - * Free Software Foundation, Inc., 59 Temple Place - Suite 330, - * Boston, MA 021110-1307, USA. - * * Based on sysfs: * sysfs is Copyright (C) 2001, 2002, 2003 Patrick Mochel * @@ -64,91 +48,106 @@ static void fill_item_path(struct config_item * item, char * buffer, int length) /* back up enough to print this bus id with '/' */ length -= cur; - strncpy(buffer + length,config_item_name(p),cur); + memcpy(buffer + length, config_item_name(p), cur); *(buffer + --length) = '/'; } } +static int configfs_get_target_path(struct config_item *item, + struct config_item *target, char *path) +{ + int depth, size; + char *s; + + depth = item_depth(item); + size = item_path_length(target) + depth * 3 - 1; + if (size > PATH_MAX) + return -ENAMETOOLONG; + + pr_debug("%s: depth = %d, size = %d\n", __func__, depth, size); + + for (s = path; depth--; s += 3) + strcpy(s,"../"); + + fill_item_path(target, path, size); + pr_debug("%s: path = '%s'\n", __func__, path); + return 0; +} + static int create_link(struct config_item *parent_item, struct config_item *item, struct dentry *dentry) { struct configfs_dirent *target_sd = item->ci_dentry->d_fsdata; - struct configfs_symlink *sl; + char *body; int ret; - ret = -ENOENT; if (!configfs_dirent_is_ready(target_sd)) - goto out; - ret = -ENOMEM; - sl = kmalloc(sizeof(struct configfs_symlink), GFP_KERNEL); - if (sl) { - sl->sl_target = config_item_get(item); + return -ENOENT; + + body = kzalloc(PAGE_SIZE, GFP_KERNEL); + if (!body) + return -ENOMEM; + + configfs_get(target_sd); + spin_lock(&configfs_dirent_lock); + if (target_sd->s_type & CONFIGFS_USET_DROPPING) { + spin_unlock(&configfs_dirent_lock); + configfs_put(target_sd); + kfree(body); + return -ENOENT; + } + target_sd->s_links++; + spin_unlock(&configfs_dirent_lock); + ret = configfs_get_target_path(parent_item, item, body); + if (!ret) + ret = configfs_create_link(target_sd, parent_item->ci_dentry, + dentry, body); + if (ret) { spin_lock(&configfs_dirent_lock); - if (target_sd->s_type & CONFIGFS_USET_DROPPING) { - spin_unlock(&configfs_dirent_lock); - config_item_put(item); - kfree(sl); - return -ENOENT; - } - list_add(&sl->sl_list, &target_sd->s_links); + target_sd->s_links--; spin_unlock(&configfs_dirent_lock); - ret = configfs_create_link(sl, parent_item->ci_dentry, - dentry); - if (ret) { - spin_lock(&configfs_dirent_lock); - list_del_init(&sl->sl_list); - spin_unlock(&configfs_dirent_lock); - config_item_put(item); - kfree(sl); - } + configfs_put(target_sd); + kfree(body); } - -out: return ret; } -static int get_target(const char *symname, struct path *path, - struct config_item **target, struct super_block *sb) +static int get_target(const char *symname, struct config_item **target, + struct super_block *sb) { + struct path path __free(path_put) = {}; int ret; - ret = kern_path(symname, LOOKUP_FOLLOW|LOOKUP_DIRECTORY, path); - if (!ret) { - if (path->dentry->d_sb == sb) { - *target = configfs_get_config_item(path->dentry); - if (!*target) { - ret = -ENOENT; - path_put(path); - } - } else { - ret = -EPERM; - path_put(path); - } - } - - return ret; + ret = kern_path(symname, LOOKUP_FOLLOW|LOOKUP_DIRECTORY, &path); + if (ret) + return ret; + if (path.dentry->d_sb != sb) + return -EPERM; + *target = configfs_get_config_item(path.dentry); + if (!*target) + return -ENOENT; + return 0; } -int configfs_symlink(struct inode *dir, struct dentry *dentry, const char *symname) +int configfs_symlink(struct mnt_idmap *idmap, struct inode *dir, + struct dentry *dentry, const char *symname) { int ret; - struct path path; struct configfs_dirent *sd; struct config_item *parent_item; struct config_item *target_item = NULL; - struct config_item_type *type; + const struct config_item_type *type; sd = dentry->d_parent->d_fsdata; /* * Fake invisibility if dir belongs to a group/default groups hierarchy * being attached */ - ret = -ENOENT; if (!configfs_dirent_is_ready(sd)) - goto out; + return -ENOENT; parent_item = configfs_get_config_item(dentry->d_parent); type = parent_item->ci_type; @@ -158,11 +157,43 @@ int configfs_symlink(struct inode *dir, struct dentry *dentry, const char *symna !type->ct_item_ops->allow_link) goto out_put; - ret = get_target(symname, &path, &target_item, dentry->d_sb); + /* + * This is really sick. What they wanted was a hybrid of + * link(2) and symlink(2) - they wanted the target resolved + * at syscall time (as link(2) would've done), be a directory + * (which link(2) would've refused to do) *AND* be a deep + * fucking magic, making the target busy from rmdir POV. + * symlink(2) is nothing of that sort, and the locking it + * gets matches the normal symlink(2) semantics. Without + * attempts to resolve the target (which might very well + * not even exist yet) done prior to locking the parent + * directory. This perversion, OTOH, needs to resolve + * the target, which would lead to obvious deadlocks if + * attempted with any directories locked. + * + * Unfortunately, that garbage is userland ABI and we should've + * said "no" back in 2005. Too late now, so we get to + * play very ugly games with locking. + * + * Try *ANYTHING* of that sort in new code, and you will + * really regret it. Just ask yourself - what could a BOFH + * do to me and do I want to find it out first-hand? + * + * AV, a thoroughly annoyed bastard. + */ + inode_unlock(dir); + ret = get_target(symname, &target_item, dentry->d_sb); + inode_lock(dir); if (ret) goto out_put; - ret = type->ct_item_ops->allow_link(parent_item, target_item); + if (dentry->d_inode || d_unhashed(dentry)) + ret = -EEXIST; + else + ret = inode_permission(&nop_mnt_idmap, dir, + MAY_WRITE | MAY_EXEC); + if (!ret) + ret = type->ct_item_ops->allow_link(parent_item, target_item); if (!ret) { mutex_lock(&configfs_symlink_mutex); ret = create_link(parent_item, target_item, dentry); @@ -173,28 +204,24 @@ int configfs_symlink(struct inode *dir, struct dentry *dentry, const char *symna } config_item_put(target_item); - path_put(&path); out_put: config_item_put(parent_item); - -out: return ret; } int configfs_unlink(struct inode *dir, struct dentry *dentry) { - struct configfs_dirent *sd = dentry->d_fsdata; - struct configfs_symlink *sl; + struct configfs_dirent *sd = dentry->d_fsdata, *target_sd; struct config_item *parent_item; - struct config_item_type *type; + const struct config_item_type *type; int ret; ret = -EPERM; /* What lack-of-symlink returns */ if (!(sd->s_type & CONFIGFS_ITEM_LINK)) goto out; - sl = sd->s_element; + target_sd = sd->s_element; parent_item = configfs_get_config_item(dentry->d_parent); type = parent_item->ci_type; @@ -208,21 +235,18 @@ int configfs_unlink(struct inode *dir, struct dentry *dentry) /* * drop_link() must be called before - * list_del_init(&sl->sl_list), so that the order of + * decrementing target's ->s_links, so that the order of * drop_link(this, target) and drop_item(target) is preserved. */ if (type && type->ct_item_ops && type->ct_item_ops->drop_link) type->ct_item_ops->drop_link(parent_item, - sl->sl_target); + target_sd->s_element); spin_lock(&configfs_dirent_lock); - list_del_init(&sl->sl_list); + target_sd->s_links--; spin_unlock(&configfs_dirent_lock); - - /* Put reference from create_link() */ - config_item_put(sl->sl_target); - kfree(sl); + configfs_put(target_sd); config_item_put(parent_item); @@ -232,83 +256,8 @@ out: return ret; } -static int configfs_get_target_path(struct config_item * item, struct config_item * target, - char *path) -{ - char * s; - int depth, size; - - depth = item_depth(item); - size = item_path_length(target) + depth * 3 - 1; - if (size > PATH_MAX) - return -ENAMETOOLONG; - - pr_debug("%s: depth = %d, size = %d\n", __func__, depth, size); - - for (s = path; depth--; s += 3) - strcpy(s,"../"); - - fill_item_path(target, path, size); - pr_debug("%s: path = '%s'\n", __func__, path); - - return 0; -} - -static int configfs_getlink(struct dentry *dentry, char * path) -{ - struct config_item *item, *target_item; - int error = 0; - - item = configfs_get_config_item(dentry->d_parent); - if (!item) - return -EINVAL; - - target_item = configfs_get_config_item(dentry); - if (!target_item) { - config_item_put(item); - return -EINVAL; - } - - down_read(&configfs_rename_sem); - error = configfs_get_target_path(item, target_item, path); - up_read(&configfs_rename_sem); - - config_item_put(item); - config_item_put(target_item); - return error; - -} - -static void *configfs_follow_link(struct dentry *dentry, struct nameidata *nd) -{ - int error = -ENOMEM; - unsigned long page = get_zeroed_page(GFP_KERNEL); - - if (page) { - error = configfs_getlink(dentry, (char *)page); - if (!error) { - nd_set_link(nd, (char *)page); - return (void *)page; - } - } - - nd_set_link(nd, ERR_PTR(error)); - return NULL; -} - -static void configfs_put_link(struct dentry *dentry, struct nameidata *nd, - void *cookie) -{ - if (cookie) { - unsigned long page = (unsigned long)cookie; - free_page(page); - } -} - const struct inode_operations configfs_symlink_inode_operations = { - .follow_link = configfs_follow_link, - .readlink = generic_readlink, - .put_link = configfs_put_link, + .get_link = simple_get_link, .setattr = configfs_setattr, }; |