v4.19.13 snapshot.
diff --git a/fs/configfs/Kconfig b/fs/configfs/Kconfig
new file mode 100644
index 0000000..9febcde
--- /dev/null
+++ b/fs/configfs/Kconfig
@@ -0,0 +1,11 @@
+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
+ view of kernel objects, configfs is a filesystem-based manager
+ of kernel objects, or config_items.
+
+ Both sysfs and configfs can and should exist together on the
+ same system. One is not a replacement for the other.
diff --git a/fs/configfs/Makefile b/fs/configfs/Makefile
new file mode 100644
index 0000000..00ffb27
--- /dev/null
+++ b/fs/configfs/Makefile
@@ -0,0 +1,7 @@
+#
+# Makefile for the configfs virtual filesystem
+#
+
+obj-$(CONFIG_CONFIGFS_FS) += configfs.o
+
+configfs-objs := inode.o file.o dir.o symlink.o mount.o item.o
diff --git a/fs/configfs/configfs_internal.h b/fs/configfs/configfs_internal.h
new file mode 100644
index 0000000..ccc31fa
--- /dev/null
+++ b/fs/configfs/configfs_internal.h
@@ -0,0 +1,173 @@
+/* -*- mode: c; c-basic-offset:8; -*-
+ * vim: noexpandtab sw=8 ts=8 sts=0:
+ *
+ * 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_dirent {
+ atomic_t s_count;
+ int s_dependent_count;
+ struct list_head s_sibling;
+ struct list_head s_children;
+ struct list_head s_links;
+ void * s_element;
+ int s_type;
+ umode_t s_mode;
+ struct dentry * s_dentry;
+ struct iattr * s_iattr;
+#ifdef CONFIG_LOCKDEP
+ int s_depth;
+#endif
+};
+
+#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 | CONFIGFS_ITEM_BIN_ATTR)
+
+extern struct mutex configfs_symlink_mutex;
+extern spinlock_t configfs_dirent_lock;
+
+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, void (*init)(struct inode *));
+
+extern int configfs_create_file(struct config_item *, const struct configfs_attribute *);
+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);
+extern int configfs_dirent_is_ready(struct configfs_dirent *);
+
+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 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 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,
+ 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);
+
+static inline struct config_item * to_item(struct dentry * dentry)
+{
+ struct configfs_dirent * sd = dentry->d_fsdata;
+ return ((struct config_item *) sd->s_element);
+}
+
+static inline struct configfs_attribute * to_attr(struct dentry * dentry)
+{
+ struct configfs_dirent * sd = dentry->d_fsdata;
+ 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;
+
+ 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);
+ }
+ spin_unlock(&dentry->d_lock);
+
+ return item;
+}
+
+static inline void release_configfs_dirent(struct configfs_dirent * sd)
+{
+ if (!(sd->s_type & CONFIGFS_ROOT)) {
+ kfree(sd->s_iattr);
+ kmem_cache_free(configfs_dir_cachep, sd);
+ }
+}
+
+static inline struct configfs_dirent * configfs_get(struct configfs_dirent * sd)
+{
+ if (sd) {
+ WARN_ON(!atomic_read(&sd->s_count));
+ atomic_inc(&sd->s_count);
+ }
+ return sd;
+}
+
+static inline void configfs_put(struct configfs_dirent * sd)
+{
+ WARN_ON(!atomic_read(&sd->s_count));
+ if (atomic_dec_and_test(&sd->s_count))
+ release_configfs_dirent(sd);
+}
+
diff --git a/fs/configfs/dir.c b/fs/configfs/dir.c
new file mode 100644
index 0000000..39843fa
--- /dev/null
+++ b/fs/configfs/dir.c
@@ -0,0 +1,1939 @@
+/* -*- mode: c; c-basic-offset: 8; -*-
+ * vim: noexpandtab sw=8 ts=8 sts=0:
+ *
+ * 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
+ *
+ * configfs Copyright (C) 2005 Oracle. All rights reserved.
+ */
+
+#undef DEBUG
+
+#include <linux/fs.h>
+#include <linux/mount.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/err.h>
+
+#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
+ * Mutators of configfs_dirent linkage must *both* have the proper inode locked
+ * and configfs_dirent_lock locked, in that order.
+ * This allows one to safely traverse configfs_dirent trees and symlinks without
+ * having to lock inodes.
+ *
+ * Protects setting of CONFIGFS_USET_DROPPING: checking the flag
+ * unlocked is not reliable unless in detach_groups() called from
+ * rmdir()/unregister() and from configfs_attach_group()
+ */
+DEFINE_SPINLOCK(configfs_dirent_lock);
+
+static void configfs_d_iput(struct dentry * dentry,
+ struct inode * inode)
+{
+ struct configfs_dirent *sd = dentry->d_fsdata;
+
+ if (sd) {
+ /* Coordinate with configfs_readdir */
+ spin_lock(&configfs_dirent_lock);
+ /* Coordinate with configfs_attach_attr where will increase
+ * sd->s_count and update sd->s_dentry to new allocated one.
+ * Only set sd->dentry to null when this dentry is the only
+ * sd owner.
+ * If not do so, configfs_d_iput may run just after
+ * configfs_attach_attr and set sd->s_dentry to null
+ * even it's still in use.
+ */
+ if (atomic_read(&sd->s_count) <= 2)
+ sd->s_dentry = NULL;
+
+ spin_unlock(&configfs_dirent_lock);
+ configfs_put(sd);
+ }
+ iput(inode);
+}
+
+const struct dentry_operations configfs_dentry_ops = {
+ .d_iput = configfs_d_iput,
+ .d_delete = always_delete_dentry,
+};
+
+#ifdef CONFIG_LOCKDEP
+
+/*
+ * Helpers to make lockdep happy with our recursive locking of default groups'
+ * inodes (see configfs_attach_group() and configfs_detach_group()).
+ * We put default groups i_mutexes in separate classes according to their depth
+ * from the youngest non-default group ancestor.
+ *
+ * For a non-default group A having default groups A/B, A/C, and A/C/D, default
+ * groups A/B and A/C will have their inode's mutex in class
+ * default_group_class[0], and default group A/C/D will be in
+ * default_group_class[1].
+ *
+ * The lock classes are declared and assigned in inode.c, according to the
+ * s_depth value.
+ * The s_depth value is initialized to -1, adjusted to >= 0 when attaching
+ * default groups, and reset to -1 when all default groups are attached. During
+ * attachment, if configfs_create() sees s_depth > 0, the lock class of the new
+ * inode's mutex is set to default_group_class[s_depth - 1].
+ */
+
+static void configfs_init_dirent_depth(struct configfs_dirent *sd)
+{
+ sd->s_depth = -1;
+}
+
+static void configfs_set_dir_dirent_depth(struct configfs_dirent *parent_sd,
+ struct configfs_dirent *sd)
+{
+ int parent_depth = parent_sd->s_depth;
+
+ if (parent_depth >= 0)
+ sd->s_depth = parent_depth + 1;
+}
+
+static void
+configfs_adjust_dir_dirent_depth_before_populate(struct configfs_dirent *sd)
+{
+ /*
+ * item's i_mutex class is already setup, so s_depth is now only
+ * used to set new sub-directories s_depth, which is always done
+ * with item's i_mutex locked.
+ */
+ /*
+ * sd->s_depth == -1 iff we are a non default group.
+ * else (we are a default group) sd->s_depth > 0 (see
+ * create_dir()).
+ */
+ if (sd->s_depth == -1)
+ /*
+ * We are a non default group and we are going to create
+ * default groups.
+ */
+ sd->s_depth = 0;
+}
+
+static void
+configfs_adjust_dir_dirent_depth_after_populate(struct configfs_dirent *sd)
+{
+ /* We will not create default groups anymore. */
+ sd->s_depth = -1;
+}
+
+#else /* CONFIG_LOCKDEP */
+
+static void configfs_init_dirent_depth(struct configfs_dirent *sd)
+{
+}
+
+static void configfs_set_dir_dirent_depth(struct configfs_dirent *parent_sd,
+ struct configfs_dirent *sd)
+{
+}
+
+static void
+configfs_adjust_dir_dirent_depth_before_populate(struct configfs_dirent *sd)
+{
+}
+
+static void
+configfs_adjust_dir_dirent_depth_after_populate(struct configfs_dirent *sd)
+{
+}
+
+#endif /* CONFIG_LOCKDEP */
+
+/*
+ * 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)
+{
+ struct configfs_dirent * sd;
+
+ sd = kmem_cache_zalloc(configfs_dir_cachep, GFP_KERNEL);
+ if (!sd)
+ 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;
+ configfs_init_dirent_depth(sd);
+ spin_lock(&configfs_dirent_lock);
+ if (parent_sd->s_type & CONFIGFS_USET_DROPPING) {
+ spin_unlock(&configfs_dirent_lock);
+ kmem_cache_free(configfs_dir_cachep, sd);
+ return ERR_PTR(-ENOENT);
+ }
+ list_add(&sd->s_sibling, &parent_sd->s_children);
+ spin_unlock(&configfs_dirent_lock);
+
+ return sd;
+}
+
+/*
+ *
+ * Return -EEXIST if there is already a configfs element with the same
+ * name for the same parent.
+ *
+ * called with parent inode's i_mutex held
+ */
+static int configfs_dirent_exists(struct configfs_dirent *parent_sd,
+ const unsigned char *new)
+{
+ struct configfs_dirent * sd;
+
+ list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
+ if (sd->s_element) {
+ const unsigned char *existing = configfs_get_name(sd);
+ if (strcmp(existing, new))
+ continue;
+ else
+ return -EEXIST;
+ }
+ }
+
+ return 0;
+}
+
+
+int configfs_make_dirent(struct configfs_dirent * parent_sd,
+ struct dentry * dentry, void * element,
+ umode_t mode, int type)
+{
+ struct configfs_dirent * sd;
+
+ sd = configfs_new_dirent(parent_sd, element, type);
+ if (IS_ERR(sd))
+ return PTR_ERR(sd);
+
+ sd->s_mode = mode;
+ sd->s_dentry = dentry;
+ if (dentry)
+ dentry->d_fsdata = configfs_get(sd);
+
+ return 0;
+}
+
+static void 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);
+}
+
+static void configfs_init_file(struct inode * inode)
+{
+ inode->i_size = PAGE_SIZE;
+ inode->i_fop = &configfs_file_operations;
+}
+
+static void configfs_init_bin_file(struct inode *inode)
+{
+ inode->i_size = 0;
+ inode->i_fop = &configfs_bin_file_operations;
+}
+
+static void init_symlink(struct inode * inode)
+{
+ inode->i_op = &configfs_symlink_inode_operations;
+}
+
+/**
+ * configfs_create_dir - create a directory for an config_item.
+ * @item: config_itemwe're creating directory for.
+ * @dentry: config_item's dentry.
+ *
+ * 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)
+{
+ int error;
+ umode_t mode = S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO;
+ struct dentry *p = dentry->d_parent;
+
+ BUG_ON(!item);
+
+ error = configfs_dirent_exists(p->d_fsdata, dentry->d_name.name);
+ if (unlikely(error))
+ return error;
+
+ error = configfs_make_dirent(p->d_fsdata, dentry, item, mode,
+ CONFIGFS_DIR | CONFIGFS_USET_CREATING);
+ if (unlikely(error))
+ return error;
+
+ configfs_set_dir_dirent_depth(p->d_fsdata, dentry->d_fsdata);
+ error = configfs_create(dentry, mode, init_dir);
+ if (!error) {
+ inc_nlink(d_inode(p));
+ item->ci_dentry = dentry;
+ } else {
+ 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 error;
+}
+
+/*
+ * Allow userspace to create new entries under a new directory created with
+ * configfs_create_dir(), and under all of its chidlren directories recursively.
+ * @sd configfs_dirent of the new directory to validate
+ *
+ * Caller must hold configfs_dirent_lock.
+ */
+static void configfs_dir_set_ready(struct configfs_dirent *sd)
+{
+ struct configfs_dirent *child_sd;
+
+ sd->s_type &= ~CONFIGFS_USET_CREATING;
+ list_for_each_entry(child_sd, &sd->s_children, s_sibling)
+ if (child_sd->s_type & CONFIGFS_USET_CREATING)
+ configfs_dir_set_ready(child_sd);
+}
+
+/*
+ * Check that a directory does not belong to a directory hierarchy being
+ * attached and not validated yet.
+ * @sd configfs_dirent of the directory to check
+ *
+ * @return non-zero iff the directory was validated
+ *
+ * Note: takes configfs_dirent_lock, so the result may change from false to true
+ * in two consecutive calls, but never from true to false.
+ */
+int configfs_dirent_is_ready(struct configfs_dirent *sd)
+{
+ int ret;
+
+ spin_lock(&configfs_dirent_lock);
+ ret = !(sd->s_type & CONFIGFS_USET_CREATING);
+ spin_unlock(&configfs_dirent_lock);
+
+ return ret;
+}
+
+int configfs_create_link(struct configfs_symlink *sl,
+ struct dentry *parent,
+ struct dentry *dentry)
+{
+ int err = 0;
+ umode_t mode = S_IFLNK | S_IRWXUGO;
+
+ 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;
+}
+
+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_really_is_positive(d))
+ simple_rmdir(d_inode(parent),d);
+
+ pr_debug(" o %pd removing done (%d)\n", d, d_count(d));
+
+ dput(parent);
+}
+
+/**
+ * configfs_remove_dir - remove an config_item's directory.
+ * @item: config_item we're removing.
+ *
+ * The only thing special about this is that we remove any files in
+ * the directory before we remove the directory, and we've inlined
+ * what used to be configfs_rmdir() below, instead of calling separately.
+ *
+ * Caller holds the mutex of the item's inode
+ */
+
+static void configfs_remove_dir(struct config_item * item)
+{
+ struct dentry * dentry = dget(item->ci_dentry);
+
+ if (!dentry)
+ return;
+
+ remove_dir(dentry);
+ /**
+ * Drop reference from dget() on entrance.
+ */
+ 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;
+
+ spin_lock(&configfs_dirent_lock);
+ dentry->d_fsdata = configfs_get(sd);
+ sd->s_dentry = dentry;
+ spin_unlock(&configfs_dirent_lock);
+
+ error = configfs_create(dentry, (attr->ca_mode & S_IALLUGO) | S_IFREG,
+ (sd->s_type & CONFIGFS_ITEM_BIN_ATTR) ?
+ configfs_init_bin_file :
+ configfs_init_file);
+ if (error)
+ configfs_put(sd);
+ return error;
+}
+
+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;
+
+ /*
+ * Fake invisibility if dir belongs to a group/default groups hierarchy
+ * being attached
+ *
+ * This forbids userspace to read/write attributes of items which may
+ * 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;
+
+ 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);
+ break;
+ }
+ }
+
+ if (!found) {
+ /*
+ * If it doesn't exist and it isn't a NOT_PINNED item,
+ * it must be negative.
+ */
+ if (dentry->d_name.len > NAME_MAX)
+ return ERR_PTR(-ENAMETOOLONG);
+ d_add(dentry, NULL);
+ return NULL;
+ }
+
+out:
+ return ERR_PTR(err);
+}
+
+/*
+ * Only subdirectories count here. Files (CONFIGFS_NOT_PINNED) are
+ * attributes and are removed by rmdir(). We recurse, setting
+ * CONFIGFS_USET_DROPPING on all children that are candidates for
+ * default detach.
+ * If there is an error, the caller will reset the flags via
+ * configfs_detach_rollback().
+ */
+static int configfs_detach_prep(struct dentry *dentry, struct dentry **wait)
+{
+ struct configfs_dirent *parent_sd = dentry->d_fsdata;
+ struct configfs_dirent *sd;
+ int ret;
+
+ /* Mark that we're trying to drop the group */
+ parent_sd->s_type |= CONFIGFS_USET_DROPPING;
+
+ ret = -EBUSY;
+ if (!list_empty(&parent_sd->s_links))
+ goto out;
+
+ ret = 0;
+ list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
+ if (!sd->s_element ||
+ (sd->s_type & CONFIGFS_NOT_PINNED))
+ continue;
+ if (sd->s_type & CONFIGFS_USET_DEFAULT) {
+ /* Abort if racing with mkdir() */
+ if (sd->s_type & CONFIGFS_USET_IN_MKDIR) {
+ if (wait)
+ *wait= dget(sd->s_dentry);
+ return -EAGAIN;
+ }
+
+ /*
+ * Yup, recursive. If there's a problem, blame
+ * deep nesting of default_groups
+ */
+ ret = configfs_detach_prep(sd->s_dentry, wait);
+ if (!ret)
+ continue;
+ } else
+ ret = -ENOTEMPTY;
+
+ break;
+ }
+
+out:
+ return ret;
+}
+
+/*
+ * Walk the tree, resetting CONFIGFS_USET_DROPPING wherever it was
+ * set.
+ */
+static void configfs_detach_rollback(struct dentry *dentry)
+{
+ struct configfs_dirent *parent_sd = dentry->d_fsdata;
+ struct configfs_dirent *sd;
+
+ parent_sd->s_type &= ~CONFIGFS_USET_DROPPING;
+
+ list_for_each_entry(sd, &parent_sd->s_children, s_sibling)
+ if (sd->s_type & CONFIGFS_USET_DEFAULT)
+ configfs_detach_rollback(sd->s_dentry);
+}
+
+static void detach_attrs(struct config_item * item)
+{
+ struct dentry * dentry = dget(item->ci_dentry);
+ struct configfs_dirent * parent_sd;
+ struct configfs_dirent * sd, * tmp;
+
+ if (!dentry)
+ return;
+
+ pr_debug("configfs %s: dropping attrs for dir\n",
+ dentry->d_name.name);
+
+ parent_sd = dentry->d_fsdata;
+ list_for_each_entry_safe(sd, tmp, &parent_sd->s_children, s_sibling) {
+ if (!sd->s_element || !(sd->s_type & CONFIGFS_NOT_PINNED))
+ continue;
+ spin_lock(&configfs_dirent_lock);
+ list_del_init(&sd->s_sibling);
+ spin_unlock(&configfs_dirent_lock);
+ configfs_drop_dentry(sd, dentry);
+ configfs_put(sd);
+ }
+
+ /**
+ * Drop reference from dget() on entrance.
+ */
+ dput(dentry);
+}
+
+static int populate_attrs(struct config_item *item)
+{
+ const struct config_item_type *t = item->ci_type;
+ struct configfs_attribute *attr;
+ struct configfs_bin_attribute *bin_attr;
+ int error = 0;
+ int i;
+
+ if (!t)
+ return -EINVAL;
+ if (t->ct_attrs) {
+ for (i = 0; (attr = t->ct_attrs[i]) != NULL; i++) {
+ if ((error = configfs_create_file(item, attr)))
+ break;
+ }
+ }
+ if (t->ct_bin_attrs) {
+ for (i = 0; (bin_attr = t->ct_bin_attrs[i]) != NULL; i++) {
+ error = configfs_create_bin_file(item, bin_attr);
+ if (error)
+ break;
+ }
+ }
+
+ if (error)
+ detach_attrs(item);
+
+ return error;
+}
+
+static int configfs_attach_group(struct config_item *parent_item,
+ struct config_item *item,
+ struct dentry *dentry);
+static void configfs_detach_group(struct config_item *item);
+
+static void detach_groups(struct config_group *group)
+{
+ struct dentry * dentry = dget(group->cg_item.ci_dentry);
+ struct dentry *child;
+ struct configfs_dirent *parent_sd;
+ struct configfs_dirent *sd, *tmp;
+
+ if (!dentry)
+ return;
+
+ parent_sd = dentry->d_fsdata;
+ list_for_each_entry_safe(sd, tmp, &parent_sd->s_children, s_sibling) {
+ if (!sd->s_element ||
+ !(sd->s_type & CONFIGFS_USET_DEFAULT))
+ continue;
+
+ child = sd->s_dentry;
+
+ inode_lock(d_inode(child));
+
+ configfs_detach_group(sd->s_element);
+ d_inode(child)->i_flags |= S_DEAD;
+ dont_mount(child);
+
+ inode_unlock(d_inode(child));
+
+ d_delete(child);
+ dput(child);
+ }
+
+ /**
+ * Drop reference from dget() on entrance.
+ */
+ dput(dentry);
+}
+
+/*
+ * This fakes mkdir(2) on a default_groups[] entry. It
+ * creates a dentry, attachs it, and then does fixup
+ * on the sd->s_type.
+ *
+ * We could, perhaps, tweak our parent's ->mkdir for a minute and
+ * try using vfs_mkdir. Just a thought.
+ */
+static int create_default_group(struct config_group *parent_group,
+ struct config_group *group)
+{
+ int ret;
+ struct configfs_dirent *sd;
+ /* We trust the caller holds a reference to parent */
+ struct dentry *child, *parent = parent_group->cg_item.ci_dentry;
+
+ if (!group->cg_item.ci_name)
+ group->cg_item.ci_name = group->cg_item.ci_namebuf;
+
+ ret = -ENOMEM;
+ child = d_alloc_name(parent, group->cg_item.ci_name);
+ if (child) {
+ d_add(child, NULL);
+
+ ret = configfs_attach_group(&parent_group->cg_item,
+ &group->cg_item, child);
+ if (!ret) {
+ sd = child->d_fsdata;
+ sd->s_type |= CONFIGFS_USET_DEFAULT;
+ } else {
+ BUG_ON(d_inode(child));
+ d_drop(child);
+ dput(child);
+ }
+ }
+
+ return ret;
+}
+
+static int populate_groups(struct config_group *group)
+{
+ struct config_group *new_group;
+ int ret = 0;
+
+ list_for_each_entry(new_group, &group->default_groups, group_entry) {
+ ret = create_default_group(group, new_group);
+ 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.
+ */
+
+static void unlink_obj(struct config_item *item)
+{
+ struct config_group *group;
+
+ group = item->ci_group;
+ if (group) {
+ list_del_init(&item->ci_entry);
+
+ item->ci_group = NULL;
+ item->ci_parent = NULL;
+
+ /* Drop the reference for ci_entry */
+ config_item_put(item);
+
+ /* Drop the reference for ci_parent */
+ config_group_put(group);
+ }
+}
+
+static void link_obj(struct config_item *parent_item, struct config_item *item)
+{
+ /*
+ * Parent seems redundant with group, but it makes certain
+ * traversals much nicer.
+ */
+ item->ci_parent = parent_item;
+
+ /*
+ * We hold a reference on the parent for the child's ci_parent
+ * link.
+ */
+ item->ci_group = config_group_get(to_config_group(parent_item));
+ list_add_tail(&item->ci_entry, &item->ci_group->cg_children);
+
+ /*
+ * We hold a reference on the child for ci_entry on the parent's
+ * cg_children
+ */
+ config_item_get(item);
+}
+
+static void unlink_group(struct config_group *group)
+{
+ struct config_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);
+}
+
+static void link_group(struct config_group *parent_group, struct config_group *group)
+{
+ struct config_group *new_group;
+ struct configfs_subsystem *subsys = NULL; /* gcc is a turd */
+
+ link_obj(&parent_group->cg_item, &group->cg_item);
+
+ if (parent_group->cg_subsys)
+ subsys = parent_group->cg_subsys;
+ else if (configfs_is_root(&parent_group->cg_item))
+ subsys = to_configfs_subsystem(group);
+ else
+ BUG();
+ group->cg_subsys = subsys;
+
+ list_for_each_entry(new_group, &group->default_groups, group_entry)
+ link_group(group, new_group);
+}
+
+/*
+ * The goal is that configfs_attach_item() (and
+ * configfs_attach_group()) can be called from either the VFS or this
+ * module. That is, they assume that the items have been created,
+ * the dentry allocated, and the dcache is all ready to go.
+ *
+ * If they fail, they must clean up after themselves as if they
+ * had never been called. The caller (VFS or local function) will
+ * handle cleaning up the dcache bits.
+ *
+ * configfs_detach_group() and configfs_detach_item() behave similarly on
+ * the way out. They assume that the proper semaphores are held, they
+ * clean up the configfs items, and they expect their callers will
+ * handle the dcache bits.
+ */
+static int configfs_attach_item(struct config_item *parent_item,
+ struct config_item *item,
+ struct dentry *dentry)
+{
+ int ret;
+
+ ret = configfs_create_dir(item, dentry);
+ if (!ret) {
+ ret = populate_attrs(item);
+ if (ret) {
+ /*
+ * We are going to remove an inode and its dentry but
+ * the VFS may already have hit and used them. Thus,
+ * we must lock them as rmdir() would.
+ */
+ inode_lock(d_inode(dentry));
+ configfs_remove_dir(item);
+ d_inode(dentry)->i_flags |= S_DEAD;
+ dont_mount(dentry);
+ inode_unlock(d_inode(dentry));
+ d_delete(dentry);
+ }
+ }
+
+ return ret;
+}
+
+/* Caller holds the mutex of the item's inode */
+static void configfs_detach_item(struct config_item *item)
+{
+ detach_attrs(item);
+ configfs_remove_dir(item);
+}
+
+static int configfs_attach_group(struct config_item *parent_item,
+ struct config_item *item,
+ struct dentry *dentry)
+{
+ int ret;
+ struct configfs_dirent *sd;
+
+ ret = configfs_attach_item(parent_item, item, dentry);
+ if (!ret) {
+ sd = dentry->d_fsdata;
+ sd->s_type |= CONFIGFS_USET_DIR;
+
+ /*
+ * FYI, we're faking mkdir in populate_groups()
+ * We must lock the group's inode to avoid races with the VFS
+ * which can already hit the inode and try to add/remove entries
+ * under it.
+ *
+ * We must also lock the inode to remove it safely in case of
+ * error, as rmdir() would.
+ */
+ inode_lock_nested(d_inode(dentry), I_MUTEX_CHILD);
+ configfs_adjust_dir_dirent_depth_before_populate(sd);
+ ret = populate_groups(to_config_group(item));
+ if (ret) {
+ configfs_detach_item(item);
+ d_inode(dentry)->i_flags |= S_DEAD;
+ dont_mount(dentry);
+ }
+ configfs_adjust_dir_dirent_depth_after_populate(sd);
+ inode_unlock(d_inode(dentry));
+ if (ret)
+ d_delete(dentry);
+ }
+
+ return ret;
+}
+
+/* Caller holds the mutex of the group's inode */
+static void configfs_detach_group(struct config_item *item)
+{
+ detach_groups(to_config_group(item));
+ configfs_detach_item(item);
+}
+
+/*
+ * After the item has been detached from the filesystem view, we are
+ * ready to tear it out of the hierarchy. Notify the client before
+ * we do that so they can perform any cleanup that requires
+ * navigating the hierarchy. A client does not need to provide this
+ * callback. The subsystem semaphore MUST be held by the caller, and
+ * references must be valid for both items. It also assumes the
+ * caller has validated ci_type.
+ */
+static void client_disconnect_notify(struct config_item *parent_item,
+ struct config_item *item)
+{
+ const struct config_item_type *type;
+
+ type = parent_item->ci_type;
+ BUG_ON(!type);
+
+ if (type->ct_group_ops && type->ct_group_ops->disconnect_notify)
+ type->ct_group_ops->disconnect_notify(to_config_group(parent_item),
+ item);
+}
+
+/*
+ * Drop the initial reference from make_item()/make_group()
+ * This function assumes that reference is held on item
+ * and that item holds a valid reference to the parent. Also, it
+ * assumes the caller has validated ci_type.
+ */
+static void client_drop_item(struct config_item *parent_item,
+ struct config_item *item)
+{
+ const struct config_item_type *type;
+
+ type = parent_item->ci_type;
+ BUG_ON(!type);
+
+ /*
+ * If ->drop_item() exists, it is responsible for the
+ * config_item_put().
+ */
+ if (type->ct_group_ops && type->ct_group_ops->drop_item)
+ type->ct_group_ops->drop_item(to_config_group(parent_item),
+ item);
+ else
+ config_item_put(item);
+}
+
+#ifdef DEBUG
+static void configfs_dump_one(struct configfs_dirent *sd, int level)
+{
+ pr_info("%*s\"%s\":\n", level, " ", configfs_get_name(sd));
+
+#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);
+ type_print(CONFIGFS_ITEM_LINK);
+ type_print(CONFIGFS_USET_DIR);
+ type_print(CONFIGFS_USET_DEFAULT);
+ type_print(CONFIGFS_USET_DROPPING);
+#undef type_print
+}
+
+static int configfs_dump(struct configfs_dirent *sd, int level)
+{
+ struct configfs_dirent *child_sd;
+ int ret = 0;
+
+ configfs_dump_one(sd, level);
+
+ if (!(sd->s_type & (CONFIGFS_DIR|CONFIGFS_ROOT)))
+ return 0;
+
+ list_for_each_entry(child_sd, &sd->s_children, s_sibling) {
+ ret = configfs_dump(child_sd, level + 2);
+ if (ret)
+ break;
+ }
+
+ return ret;
+}
+#endif
+
+
+/*
+ * configfs_depend_item() and configfs_undepend_item()
+ *
+ * WARNING: Do not call these from a configfs callback!
+ *
+ * This describes these functions and their helpers.
+ *
+ * Allow another kernel system to depend on a config_item. If this
+ * happens, the item cannot go away until the dependent can live without
+ * it. The idea is to give client modules as simple an interface as
+ * possible. When a system asks them to depend on an item, they just
+ * call configfs_depend_item(). If the item is live and the client
+ * driver is in good shape, we'll happily do the work for them.
+ *
+ * Why is the locking complex? Because configfs uses the VFS to handle
+ * all locking, but this function is called outside the normal
+ * VFS->configfs path. So it must take VFS locks to prevent the
+ * VFS->configfs stuff (configfs_mkdir(), configfs_rmdir(), etc). This is
+ * why you can't call these functions underneath configfs callbacks.
+ *
+ * Note, btw, that this can be called at *any* time, even when a configfs
+ * subsystem isn't registered, or when configfs is loading or unloading.
+ * Just like configfs_register_subsystem(). So we take the same
+ * precautions. We pin the filesystem. We lock configfs_dirent_lock.
+ * If we can find the target item in the
+ * configfs tree, it must be part of the subsystem tree as well, so we
+ * do not need the subsystem semaphore. Holding configfs_dirent_lock helps
+ * locking out mkdir() and rmdir(), who might be racing us.
+ */
+
+/*
+ * configfs_depend_prep()
+ *
+ * Only subdirectories count here. Files (CONFIGFS_NOT_PINNED) are
+ * attributes. This is similar but not the same to configfs_detach_prep().
+ * Note that configfs_detach_prep() expects the parent to be locked when it
+ * is called, but we lock the parent *inside* configfs_depend_prep(). We
+ * do that so we can unlock it if we find nothing.
+ *
+ * Here we do a depth-first search of the dentry hierarchy looking for
+ * our object.
+ * We deliberately ignore items tagged as dropping since they are virtually
+ * dead, as well as items in the middle of attachment since they virtually
+ * do not exist yet. This completes the locking out of racing mkdir() and
+ * rmdir().
+ * Note: subdirectories in the middle of attachment start with s_type =
+ * CONFIGFS_DIR|CONFIGFS_USET_CREATING set by create_dir(). When
+ * CONFIGFS_USET_CREATING is set, we ignore the item. The actual set of
+ * s_type is in configfs_new_dirent(), which has configfs_dirent_lock.
+ *
+ * If the target is not found, -ENOENT is bubbled up.
+ *
+ * This adds a requirement that all config_items be unique!
+ *
+ * This is recursive. There isn't
+ * much on the stack, though, so folks that need this function - be careful
+ * about your stack! Patches will be accepted to make it iterative.
+ */
+static int configfs_depend_prep(struct dentry *origin,
+ struct config_item *target)
+{
+ struct configfs_dirent *child_sd, *sd;
+ int ret = 0;
+
+ BUG_ON(!origin || !origin->d_fsdata);
+ sd = origin->d_fsdata;
+
+ if (sd->s_element == target) /* Boo-yah */
+ goto out;
+
+ list_for_each_entry(child_sd, &sd->s_children, s_sibling) {
+ if ((child_sd->s_type & CONFIGFS_DIR) &&
+ !(child_sd->s_type & CONFIGFS_USET_DROPPING) &&
+ !(child_sd->s_type & CONFIGFS_USET_CREATING)) {
+ ret = configfs_depend_prep(child_sd->s_dentry,
+ target);
+ if (!ret)
+ goto out; /* Child path boo-yah */
+ }
+ }
+
+ /* We looped all our children and didn't find target */
+ ret = -ENOENT;
+
+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 *subsys_sd;
+ struct config_item *s_item = &subsys->su_group.cg_item;
+ struct dentry *root;
+
+ /*
+ * Pin the configfs filesystem. This means we can safely access
+ * the root of the configfs filesystem.
+ */
+ root = configfs_pin_fs();
+ if (IS_ERR(root))
+ return PTR_ERR(root);
+
+ /*
+ * Next, lock the root directory. We're going to check that the
+ * subsystem is really registered, and so we need to lock out
+ * configfs_[un]register_subsystem().
+ */
+ 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);
+
+out_unlock_fs:
+ inode_unlock(d_inode(root));
+
+ /*
+ * If we succeeded, the fs is pinned via other methods. If not,
+ * we're done with it anyway. So release_fs() is always right.
+ */
+ configfs_release_fs();
+
+ return ret;
+}
+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
+ * pinned, thus the subsystem is pinned, and therefore configfs is pinned.
+ */
+void configfs_undepend_item(struct config_item *target)
+{
+ struct configfs_dirent *sd;
+
+ /*
+ * Since we can trust everything is pinned, we just need
+ * configfs_dirent_lock.
+ */
+ spin_lock(&configfs_dirent_lock);
+
+ sd = target->ci_dentry->d_fsdata;
+ BUG_ON(sd->s_dependent_count < 1);
+
+ sd->s_dependent_count -= 1;
+
+ /*
+ * After this unlock, we cannot trust the item to stay alive!
+ * DO NOT REFERENCE item after this unlock.
+ */
+ spin_unlock(&configfs_dirent_lock);
+}
+EXPORT_SYMBOL(configfs_undepend_item);
+
+/*
+ * 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 int configfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
+{
+ int ret = 0;
+ int module_got = 0;
+ struct config_group *group = NULL;
+ struct config_item *item = NULL;
+ struct config_item *parent_item;
+ struct configfs_subsystem *subsys;
+ struct configfs_dirent *sd;
+ const struct config_item_type *type;
+ struct module *subsys_owner = NULL, *new_item_owner = NULL;
+ char *name;
+
+ sd = dentry->d_parent->d_fsdata;
+
+ /*
+ * Fake invisibility if dir belongs to a group/default groups hierarchy
+ * being attached
+ */
+ if (!configfs_dirent_is_ready(sd)) {
+ ret = -ENOENT;
+ goto out;
+ }
+
+ if (!(sd->s_type & CONFIGFS_USET_DIR)) {
+ ret = -EPERM;
+ 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;
+ subsys = to_config_group(parent_item)->cg_subsys;
+ BUG_ON(!subsys);
+
+ if (!type || !type->ct_group_ops ||
+ (!type->ct_group_ops->make_group &&
+ !type->ct_group_ops->make_item)) {
+ ret = -EPERM; /* Lack-of-mkdir returns -EPERM */
+ goto out_put;
+ }
+
+ /*
+ * The subsystem may belong to a different module than the item
+ * being created. We don't want to safely pin the new item but
+ * fail to pin the subsystem it sits under.
+ */
+ if (!subsys->su_group.cg_item.ci_type) {
+ ret = -EINVAL;
+ goto out_put;
+ }
+ subsys_owner = subsys->su_group.cg_item.ci_type->ct_owner;
+ if (!try_module_get(subsys_owner)) {
+ ret = -EINVAL;
+ goto out_put;
+ }
+
+ name = kmalloc(dentry->d_name.len + 1, GFP_KERNEL);
+ if (!name) {
+ ret = -ENOMEM;
+ goto out_subsys_put;
+ }
+
+ snprintf(name, dentry->d_name.len + 1, "%s", dentry->d_name.name);
+
+ mutex_lock(&subsys->su_mutex);
+ if (type->ct_group_ops->make_group) {
+ group = type->ct_group_ops->make_group(to_config_group(parent_item), name);
+ if (!group)
+ group = ERR_PTR(-ENOMEM);
+ if (!IS_ERR(group)) {
+ link_group(to_config_group(parent_item), group);
+ item = &group->cg_item;
+ } else
+ ret = PTR_ERR(group);
+ } else {
+ item = type->ct_group_ops->make_item(to_config_group(parent_item), name);
+ if (!item)
+ item = ERR_PTR(-ENOMEM);
+ if (!IS_ERR(item))
+ link_obj(parent_item, item);
+ else
+ ret = PTR_ERR(item);
+ }
+ mutex_unlock(&subsys->su_mutex);
+
+ kfree(name);
+ if (ret) {
+ /*
+ * If ret != 0, then link_obj() was never called.
+ * There are no extra references to clean up.
+ */
+ goto out_subsys_put;
+ }
+
+ /*
+ * link_obj() has been called (via link_group() for groups).
+ * From here on out, errors must clean that up.
+ */
+
+ type = item->ci_type;
+ if (!type) {
+ ret = -EINVAL;
+ goto out_unlink;
+ }
+
+ new_item_owner = type->ct_owner;
+ if (!try_module_get(new_item_owner)) {
+ ret = -EINVAL;
+ goto out_unlink;
+ }
+
+ /*
+ * I hate doing it this way, but if there is
+ * an error, module_put() probably should
+ * happen after any cleanup.
+ */
+ module_got = 1;
+
+ /*
+ * Make racing rmdir() fail if it did not tag parent with
+ * CONFIGFS_USET_DROPPING
+ * Note: if CONFIGFS_USET_DROPPING is already set, attach_group() will
+ * fail and let rmdir() terminate correctly
+ */
+ spin_lock(&configfs_dirent_lock);
+ /* This will make configfs_detach_prep() fail */
+ sd->s_type |= CONFIGFS_USET_IN_MKDIR;
+ spin_unlock(&configfs_dirent_lock);
+
+ if (group)
+ ret = configfs_attach_group(parent_item, item, dentry);
+ else
+ ret = configfs_attach_item(parent_item, item, dentry);
+
+ spin_lock(&configfs_dirent_lock);
+ sd->s_type &= ~CONFIGFS_USET_IN_MKDIR;
+ if (!ret)
+ configfs_dir_set_ready(dentry->d_fsdata);
+ spin_unlock(&configfs_dirent_lock);
+
+out_unlink:
+ if (ret) {
+ /* Tear down everything we built up */
+ mutex_lock(&subsys->su_mutex);
+
+ client_disconnect_notify(parent_item, item);
+ if (group)
+ unlink_group(group);
+ else
+ unlink_obj(item);
+ client_drop_item(parent_item, item);
+
+ mutex_unlock(&subsys->su_mutex);
+
+ if (module_got)
+ module_put(new_item_owner);
+ }
+
+out_subsys_put:
+ if (ret)
+ module_put(subsys_owner);
+
+out_put:
+ /*
+ * link_obj()/link_group() took a reference from child->parent,
+ * so the parent is safely pinned. We can drop our working
+ * reference.
+ */
+ config_item_put(parent_item);
+
+out:
+ return ret;
+}
+
+static int configfs_rmdir(struct inode *dir, struct dentry *dentry)
+{
+ struct config_item *parent_item;
+ struct config_item *item;
+ struct configfs_subsystem *subsys;
+ struct configfs_dirent *sd;
+ struct module *subsys_owner = NULL, *dead_item_owner = NULL;
+ int ret;
+
+ sd = dentry->d_fsdata;
+ if (sd->s_type & CONFIGFS_USET_DEFAULT)
+ return -EPERM;
+
+ /* Get a working ref until we have the child */
+ parent_item = configfs_get_config_item(dentry->d_parent);
+ subsys = to_config_group(parent_item)->cg_subsys;
+ BUG_ON(!subsys);
+
+ if (!parent_item->ci_type) {
+ config_item_put(parent_item);
+ return -EINVAL;
+ }
+
+ /* configfs_mkdir() shouldn't have allowed this */
+ BUG_ON(!subsys->su_group.cg_item.ci_type);
+ subsys_owner = subsys->su_group.cg_item.ci_type->ct_owner;
+
+ /*
+ * Ensure that no racing symlink() will make detach_prep() fail while
+ * the new link is temporarily attached
+ */
+ do {
+ struct dentry *wait;
+
+ mutex_lock(&configfs_symlink_mutex);
+ spin_lock(&configfs_dirent_lock);
+ /*
+ * Here's where we check for dependents. We're protected by
+ * configfs_dirent_lock.
+ * If no dependent, atomically tag the item as dropping.
+ */
+ ret = sd->s_dependent_count ? -EBUSY : 0;
+ if (!ret) {
+ ret = configfs_detach_prep(dentry, &wait);
+ if (ret)
+ configfs_detach_rollback(dentry);
+ }
+ spin_unlock(&configfs_dirent_lock);
+ mutex_unlock(&configfs_symlink_mutex);
+
+ if (ret) {
+ if (ret != -EAGAIN) {
+ config_item_put(parent_item);
+ return ret;
+ }
+
+ /* Wait until the racing operation terminates */
+ inode_lock(d_inode(wait));
+ inode_unlock(d_inode(wait));
+ dput(wait);
+ }
+ } while (ret == -EAGAIN);
+
+ /* Get a working ref for the duration of this function */
+ item = configfs_get_config_item(dentry);
+
+ /* Drop reference from above, item already holds one. */
+ config_item_put(parent_item);
+
+ if (item->ci_type)
+ dead_item_owner = item->ci_type->ct_owner;
+
+ if (sd->s_type & CONFIGFS_USET_DIR) {
+ configfs_detach_group(item);
+
+ mutex_lock(&subsys->su_mutex);
+ client_disconnect_notify(parent_item, item);
+ unlink_group(to_config_group(item));
+ } else {
+ configfs_detach_item(item);
+
+ mutex_lock(&subsys->su_mutex);
+ client_disconnect_notify(parent_item, item);
+ unlink_obj(item);
+ }
+
+ client_drop_item(parent_item, item);
+ mutex_unlock(&subsys->su_mutex);
+
+ /* Drop our reference from above */
+ config_item_put(item);
+
+ module_put(dead_item_owner);
+ module_put(subsys_owner);
+
+ return 0;
+}
+
+const struct inode_operations configfs_dir_inode_operations = {
+ .mkdir = configfs_mkdir,
+ .rmdir = configfs_rmdir,
+ .symlink = configfs_symlink,
+ .unlink = configfs_unlink,
+ .lookup = configfs_lookup,
+ .setattr = configfs_setattr,
+};
+
+const struct inode_operations configfs_root_inode_operations = {
+ .lookup = configfs_lookup,
+ .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;
+
+ inode_lock(d_inode(parent));
+
+ new_dentry = lookup_one_len(new_name, parent, strlen(new_name));
+ if (!IS_ERR(new_dentry)) {
+ if (d_really_is_negative(new_dentry)) {
+ 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);
+ }
+ inode_unlock(d_inode(parent));
+ 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;
+
+ 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;
+ }
+ inode_unlock(d_inode(dentry));
+
+ return err;
+}
+
+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;
+
+ inode_lock(d_inode(dentry));
+ spin_lock(&configfs_dirent_lock);
+ list_del_init(&cursor->s_sibling);
+ spin_unlock(&configfs_dirent_lock);
+ 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;
+ struct super_block *sb = dentry->d_sb;
+ struct configfs_dirent * parent_sd = dentry->d_fsdata;
+ struct configfs_dirent *cursor = file->private_data;
+ struct list_head *p, *q = &cursor->s_sibling;
+ ino_t ino = 0;
+
+ if (!dir_emit_dots(file, ctx))
+ return 0;
+ spin_lock(&configfs_dirent_lock);
+ if (ctx->pos == 2)
+ list_move(q, &parent_sd->s_children);
+ for (p = q->next; p != &parent_sd->s_children; p = p->next) {
+ struct configfs_dirent *next;
+ const char *name;
+ int len;
+ struct inode *inode = NULL;
+
+ next = list_entry(p, struct configfs_dirent, s_sibling);
+ if (!next->s_element)
+ continue;
+
+ /*
+ * We'll have a dentry and an inode for
+ * PINNED items and for open attribute
+ * files. We lock here to prevent a race
+ * with configfs_d_iput() clearing
+ * s_dentry before calling iput().
+ *
+ * Why do we go to the trouble? If
+ * someone has an attribute file open,
+ * the inode number should match until
+ * they close it. Beyond that, we don't
+ * care.
+ */
+ dentry = next->s_dentry;
+ if (dentry)
+ inode = d_inode(dentry);
+ if (inode)
+ ino = inode->i_ino;
+ spin_unlock(&configfs_dirent_lock);
+ if (!inode)
+ ino = iunique(sb, 2);
+
+ name = configfs_get_name(next);
+ len = strlen(name);
+
+ if (!dir_emit(ctx, name, len, ino, dt_type(next)))
+ return 0;
+
+ spin_lock(&configfs_dirent_lock);
+ list_move(q, p);
+ p = q;
+ ctx->pos++;
+ }
+ spin_unlock(&configfs_dirent_lock);
+ return 0;
+}
+
+static loff_t configfs_dir_lseek(struct file *file, loff_t offset, int whence)
+{
+ struct dentry * dentry = file->f_path.dentry;
+
+ switch (whence) {
+ case 1:
+ offset += file->f_pos;
+ case 0:
+ if (offset >= 0)
+ break;
+ default:
+ return -EINVAL;
+ }
+ if (offset != file->f_pos) {
+ file->f_pos = offset;
+ if (file->f_pos >= 2) {
+ struct configfs_dirent *sd = dentry->d_fsdata;
+ struct configfs_dirent *cursor = file->private_data;
+ struct list_head *p;
+ loff_t n = file->f_pos - 2;
+
+ spin_lock(&configfs_dirent_lock);
+ list_del(&cursor->s_sibling);
+ p = sd->s_children.next;
+ while (n && p != &sd->s_children) {
+ struct configfs_dirent *next;
+ next = list_entry(p, struct configfs_dirent,
+ s_sibling);
+ if (next->s_element)
+ n--;
+ p = p->next;
+ }
+ list_add_tail(&cursor->s_sibling, p);
+ spin_unlock(&configfs_dirent_lock);
+ }
+ }
+ return offset;
+}
+
+const struct file_operations configfs_dir_operations = {
+ .open = configfs_dir_open,
+ .release = configfs_dir_close,
+ .llseek = configfs_dir_lseek,
+ .read = generic_read_dir,
+ .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;
+ int ret;
+
+ 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);
+ if (!ret) {
+ 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));
+ 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;
+
+ mutex_lock(&subsys->su_mutex);
+ if (!group->cg_item.ci_parent->ci_group) {
+ /*
+ * The parent has already been unlinked and detached
+ * due to a rmdir.
+ */
+ goto unlink_group;
+ }
+ mutex_unlock(&subsys->su_mutex);
+
+ 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_delete(dentry);
+ inode_unlock(d_inode(parent));
+
+ dput(dentry);
+
+ mutex_lock(&subsys->su_mutex);
+unlink_group:
+ 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;
+ struct config_group *group = &subsys->su_group;
+ struct dentry *dentry;
+ struct dentry *root;
+ struct configfs_dirent *sd;
+
+ root = configfs_pin_fs();
+ if (IS_ERR(root))
+ return PTR_ERR(root);
+
+ if (!group->cg_item.ci_name)
+ group->cg_item.ci_name = group->cg_item.ci_namebuf;
+
+ sd = root->d_fsdata;
+ link_group(to_config_group(sd->s_element), group);
+
+ 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);
+ if (err) {
+ BUG_ON(d_inode(dentry));
+ d_drop(dentry);
+ dput(dentry);
+ } else {
+ spin_lock(&configfs_dirent_lock);
+ configfs_dir_set_ready(dentry->d_fsdata);
+ spin_unlock(&configfs_dirent_lock);
+ }
+ }
+
+ inode_unlock(d_inode(root));
+
+ if (err) {
+ unlink_group(group);
+ configfs_release_fs();
+ }
+
+ return err;
+}
+
+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;
+
+ if (dentry->d_parent != root) {
+ pr_err("Tried to unregister non-subsystem!\n");
+ return;
+ }
+
+ inode_lock_nested(d_inode(root),
+ I_MUTEX_PARENT);
+ 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)) {
+ 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);
+ d_inode(dentry)->i_flags |= S_DEAD;
+ dont_mount(dentry);
+ inode_unlock(d_inode(dentry));
+
+ d_delete(dentry);
+
+ inode_unlock(d_inode(root));
+
+ dput(dentry);
+
+ unlink_group(group);
+ configfs_release_fs();
+}
+
+EXPORT_SYMBOL(configfs_register_subsystem);
+EXPORT_SYMBOL(configfs_unregister_subsystem);
diff --git a/fs/configfs/file.c b/fs/configfs/file.c
new file mode 100644
index 0000000..62580db
--- /dev/null
+++ b/fs/configfs/file.c
@@ -0,0 +1,570 @@
+/* -*- mode: c; c-basic-offset: 8; -*-
+ * vim: noexpandtab sw=8 ts=8 sts=0:
+ *
+ * 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
+ *
+ * configfs Copyright (C) 2005 Oracle. All rights reserved.
+ */
+
+#include <linux/fs.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/mutex.h>
+#include <linux/vmalloc.h>
+#include <linux/uaccess.h>
+
+#include <linux/configfs.h>
+#include "configfs_internal.h"
+
+/*
+ * A simple attribute can only be 4096 characters. Why 4k? Because the
+ * original code limited it to PAGE_SIZE. That's a bad idea, though,
+ * because an attribute of 16k on ia64 won't work on x86. So we limit to
+ * 4k, our minimum common page size.
+ */
+#define SIMPLE_ATTR_SIZE 4096
+
+struct configfs_buffer {
+ size_t count;
+ loff_t pos;
+ char * page;
+ 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;
+};
+
+
+/**
+ * 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)
+{
+ struct configfs_attribute * attr = to_attr(dentry);
+ struct config_item * item = to_item(dentry->d_parent);
+ int ret = 0;
+ ssize_t count;
+
+ if (!buffer->page)
+ buffer->page = (char *) get_zeroed_page(GFP_KERNEL);
+ if (!buffer->page)
+ return -ENOMEM;
+
+ count = attr->show(item, buffer->page);
+
+ BUG_ON(count > (ssize_t)SIMPLE_ATTR_SIZE);
+ if (count >= 0) {
+ buffer->needs_read_fill = 0;
+ buffer->count = count;
+ } else
+ ret = count;
+ return ret;
+}
+
+/**
+ * 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)
+{
+ 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)))
+ 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);
+out:
+ mutex_unlock(&buffer->mutex);
+ return retval;
+}
+
+/**
+ * configfs_read_bin_file - read a binary attribute.
+ * @file: file pointer.
+ * @buf: buffer to fill.
+ * @count: number of bytes to read.
+ * @ppos: starting offset in file.
+ *
+ * Userspace wants to read a binary attribute file. The attribute
+ * descriptor is in the file's ->d_fsdata. The target item is in the
+ * directory's ->d_fsdata.
+ *
+ * We check whether we need to refill the buffer. If so we will
+ * call the attributes' attr->read() twice. The first time we
+ * will pass a NULL as a buffer pointer, which the attributes' method
+ * will use to return the size of the buffer required. If no error
+ * occurs we will allocate the buffer using vmalloc and call
+ * attr->read() again passing that buffer as an argument.
+ * Then we just copy to user-space using simple_read_from_buffer.
+ */
+
+static ssize_t
+configfs_read_bin_file(struct file *file, char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ struct configfs_buffer *buffer = file->private_data;
+ struct dentry *dentry = file->f_path.dentry;
+ struct config_item *item = to_item(dentry->d_parent);
+ struct configfs_bin_attribute *bin_attr = to_bin_attr(dentry);
+ ssize_t retval = 0;
+ ssize_t len = min_t(size_t, count, PAGE_SIZE);
+
+ mutex_lock(&buffer->mutex);
+
+ /* we don't support switching read/write modes */
+ if (buffer->write_in_progress) {
+ retval = -ETXTBSY;
+ goto out;
+ }
+ buffer->read_in_progress = true;
+
+ if (buffer->needs_read_fill) {
+ /* perform first read with buf == NULL to get extent */
+ len = bin_attr->read(item, NULL, 0);
+ if (len <= 0) {
+ retval = len;
+ goto out;
+ }
+
+ /* do not exceed the maximum value */
+ if (bin_attr->cb_max_size && len > bin_attr->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 */
+ len = bin_attr->read(item, buffer->bin_buffer, len);
+ 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;
+ }
+
+ retval = simple_read_from_buffer(buf, count, ppos, buffer->bin_buffer,
+ buffer->bin_buffer_size);
+out:
+ mutex_unlock(&buffer->mutex);
+ return retval;
+}
+
+
+/**
+ * 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.
+ */
+
+static int
+fill_write_buffer(struct configfs_buffer * buffer, const char __user * buf, size_t count)
+{
+ int error;
+
+ 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);
+ 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;
+}
+
+
+/**
+ * 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)
+{
+ struct configfs_attribute * attr = to_attr(dentry);
+ struct config_item * item = to_item(dentry->d_parent);
+
+ return attr->store(item, buffer->page, count);
+}
+
+
+/**
+ * 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.
+ */
+
+static ssize_t
+configfs_write_file(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
+{
+ struct configfs_buffer * buffer = file->private_data;
+ ssize_t len;
+
+ mutex_lock(&buffer->mutex);
+ len = fill_write_buffer(buffer, buf, count);
+ if (len > 0)
+ len = flush_write_buffer(file->f_path.dentry, buffer, len);
+ if (len > 0)
+ *ppos += len;
+ mutex_unlock(&buffer->mutex);
+ return len;
+}
+
+/**
+ * configfs_write_bin_file - write a binary attribute.
+ * @file: file pointer
+ * @buf: data to write
+ * @count: number of bytes
+ * @ppos: starting offset
+ *
+ * Writing to a binary attribute file is similar to a normal read.
+ * We buffer the consecutive writes (binary attribute files do not
+ * support lseek) in a continuously growing buffer, but we don't
+ * commit until the close of the file.
+ */
+
+static ssize_t
+configfs_write_bin_file(struct file *file, const char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ struct configfs_buffer *buffer = file->private_data;
+ struct dentry *dentry = file->f_path.dentry;
+ struct configfs_bin_attribute *bin_attr = to_bin_attr(dentry);
+ void *tbuf = NULL;
+ ssize_t len;
+
+ mutex_lock(&buffer->mutex);
+
+ /* we don't support switching read/write modes */
+ if (buffer->read_in_progress) {
+ len = -ETXTBSY;
+ goto out;
+ }
+ buffer->write_in_progress = true;
+
+ /* buffer grows? */
+ if (*ppos + count > buffer->bin_buffer_size) {
+
+ if (bin_attr->cb_max_size &&
+ *ppos + count > bin_attr->cb_max_size) {
+ len = -EFBIG;
+ goto out;
+ }
+
+ tbuf = vmalloc(*ppos + count);
+ 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,
+ *ppos + count - buffer->bin_buffer_size);
+ buffer->bin_buffer = tbuf;
+ buffer->bin_buffer_size = *ppos + count;
+ }
+
+ len = simple_write_to_buffer(buffer->bin_buffer,
+ buffer->bin_buffer_size, ppos, buf, count);
+out:
+ mutex_unlock(&buffer->mutex);
+ return len;
+}
+
+static int check_perm(struct inode * inode, struct file * file, int type)
+{
+ 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_bin_attribute *bin_attr = NULL;
+ struct configfs_buffer * buffer;
+ struct configfs_item_operations * ops = NULL;
+ int error = 0;
+
+ if (!item || !attr)
+ goto Einval;
+
+ if (type & CONFIGFS_ITEM_BIN_ATTR)
+ bin_attr = to_bin_attr(file->f_path.dentry);
+
+ /* Grab the module reference for this attribute if we have one */
+ if (!try_module_get(attr->ca_owner)) {
+ error = -ENODEV;
+ goto Done;
+ }
+
+ if (item->ci_type)
+ ops = item->ci_type->ct_item_ops;
+ else
+ goto Eaccess;
+
+ /* 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))
+ goto Eaccess;
+
+ if ((type & CONFIGFS_ITEM_ATTR) && !attr->store)
+ goto Eaccess;
+
+ if ((type & CONFIGFS_ITEM_BIN_ATTR) && !bin_attr->write)
+ goto Eaccess;
+ }
+
+ /* File needs read support.
+ * The inode's perms must say it's ok, and we there
+ * must be a show method for it.
+ */
+ if (file->f_mode & FMODE_READ) {
+ if (!(inode->i_mode & S_IRUGO))
+ goto Eaccess;
+
+ if ((type & CONFIGFS_ITEM_ATTR) && !attr->show)
+ goto Eaccess;
+
+ if ((type & CONFIGFS_ITEM_BIN_ATTR) && !bin_attr->read)
+ goto Eaccess;
+ }
+
+ /* 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->read_in_progress = false;
+ buffer->write_in_progress = false;
+ buffer->ops = ops;
+ file->private_data = buffer;
+ goto Done;
+
+ Einval:
+ error = -EINVAL;
+ goto Done;
+ Eaccess:
+ error = -EACCES;
+ Enomem:
+ module_put(attr->ca_owner);
+ Done:
+ if (error && item)
+ config_item_put(item);
+ return error;
+}
+
+static int configfs_release(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 0;
+}
+
+static int configfs_open_file(struct inode *inode, struct file *filp)
+{
+ return check_perm(inode, filp, CONFIGFS_ITEM_ATTR);
+}
+
+static int configfs_open_bin_file(struct inode *inode, struct file *filp)
+{
+ return check_perm(inode, filp, CONFIGFS_ITEM_BIN_ATTR);
+}
+
+static int configfs_release_bin_file(struct inode *inode, struct file *filp)
+{
+ struct configfs_buffer *buffer = filp->private_data;
+ struct dentry *dentry = filp->f_path.dentry;
+ struct config_item *item = to_item(dentry->d_parent);
+ struct configfs_bin_attribute *bin_attr = to_bin_attr(dentry);
+ ssize_t len = 0;
+ int ret;
+
+ buffer->read_in_progress = false;
+
+ if (buffer->write_in_progress) {
+ buffer->write_in_progress = false;
+
+ len = bin_attr->write(item, buffer->bin_buffer,
+ buffer->bin_buffer_size);
+
+ /* vfree on NULL is safe */
+ vfree(buffer->bin_buffer);
+ buffer->bin_buffer = NULL;
+ buffer->bin_buffer_size = 0;
+ buffer->needs_read_fill = 1;
+ }
+
+ ret = configfs_release(inode, filp);
+ if (len < 0)
+ return len;
+ return ret;
+}
+
+
+const struct file_operations configfs_file_operations = {
+ .read = configfs_read_file,
+ .write = configfs_write_file,
+ .llseek = generic_file_llseek,
+ .open = configfs_open_file,
+ .release = configfs_release,
+};
+
+const struct file_operations configfs_bin_file_operations = {
+ .read = configfs_read_bin_file,
+ .write = configfs_write_bin_file,
+ .llseek = NULL, /* bin file is not seekable */
+ .open = configfs_open_bin_file,
+ .release = configfs_release_bin_file,
+};
+
+/**
+ * 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 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;
+
+ inode_lock_nested(d_inode(dir), I_MUTEX_NORMAL);
+ error = configfs_make_dirent(parent_sd, NULL, (void *) attr, mode,
+ CONFIGFS_ITEM_ATTR);
+ inode_unlock(d_inode(dir));
+
+ return error;
+}
+
+/**
+ * configfs_create_bin_file - create a binary attribute file for an item.
+ * @item: item we're creating for.
+ * @attr: atrribute descriptor.
+ */
+
+int configfs_create_bin_file(struct config_item *item,
+ const struct configfs_bin_attribute *bin_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;
+
+ inode_lock_nested(dir->d_inode, I_MUTEX_NORMAL);
+ error = configfs_make_dirent(parent_sd, NULL, (void *) bin_attr, mode,
+ CONFIGFS_ITEM_BIN_ATTR);
+ inode_unlock(dir->d_inode);
+
+ return error;
+}
diff --git a/fs/configfs/inode.c b/fs/configfs/inode.c
new file mode 100644
index 0000000..28ef9e5
--- /dev/null
+++ b/fs/configfs/inode.c
@@ -0,0 +1,282 @@
+/* -*- mode: c; c-basic-offset: 8; -*-
+ * vim: noexpandtab sw=8 ts=8 sts=0:
+ *
+ * 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
+ * information.
+ */
+
+#undef DEBUG
+
+#include <linux/pagemap.h>
+#include <linux/namei.h>
+#include <linux/backing-dev.h>
+#include <linux/capability.h>
+#include <linux/sched.h>
+#include <linux/lockdep.h>
+#include <linux/slab.h>
+
+#include <linux/configfs.h>
+#include "configfs_internal.h"
+
+#ifdef CONFIG_LOCKDEP
+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 const struct inode_operations configfs_inode_operations ={
+ .setattr = configfs_setattr,
+};
+
+int configfs_setattr(struct dentry * dentry, struct iattr * iattr)
+{
+ struct inode * inode = d_inode(dentry);
+ struct configfs_dirent * sd = dentry->d_fsdata;
+ struct iattr * sd_iattr;
+ unsigned int ia_valid = iattr->ia_valid;
+ int error;
+
+ if (!sd)
+ return -EINVAL;
+
+ sd_iattr = sd->s_iattr;
+ if (!sd_iattr) {
+ /* setting attributes for the first time, allocate now */
+ sd_iattr = kzalloc(sizeof(struct iattr), GFP_KERNEL);
+ if (!sd_iattr)
+ return -ENOMEM;
+ /* assign default attributes */
+ 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(inode);
+ sd->s_iattr = sd_iattr;
+ }
+ /* attributes were changed atleast once in past */
+
+ error = simple_setattr(dentry, iattr);
+ if (error)
+ return error;
+
+ if (ia_valid & ATTR_UID)
+ sd_iattr->ia_uid = iattr->ia_uid;
+ if (ia_valid & ATTR_GID)
+ sd_iattr->ia_gid = iattr->ia_gid;
+ if (ia_valid & ATTR_ATIME)
+ sd_iattr->ia_atime = timespec64_trunc(iattr->ia_atime,
+ inode->i_sb->s_time_gran);
+ if (ia_valid & ATTR_MTIME)
+ sd_iattr->ia_mtime = timespec64_trunc(iattr->ia_mtime,
+ inode->i_sb->s_time_gran);
+ if (ia_valid & ATTR_CTIME)
+ sd_iattr->ia_ctime = timespec64_trunc(iattr->ia_ctime,
+ inode->i_sb->s_time_gran);
+ if (ia_valid & ATTR_MODE) {
+ umode_t mode = iattr->ia_mode;
+
+ if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID))
+ mode &= ~S_ISGID;
+ sd_iattr->ia_mode = sd->s_mode = mode;
+ }
+
+ return error;
+}
+
+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(inode);
+}
+
+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;
+}
+
+struct inode *configfs_new_inode(umode_t mode, struct configfs_dirent *sd,
+ struct super_block *s)
+{
+ struct inode * inode = new_inode(s);
+ if (inode) {
+ inode->i_ino = get_next_ino();
+ inode->i_mapping->a_ops = &configfs_aops;
+ inode->i_op = &configfs_inode_operations;
+
+ if (sd->s_iattr) {
+ /* sysfs_dirent has non-default attributes
+ * get them for the new inode from persistent copy
+ * in sysfs_dirent
+ */
+ set_inode_attr(inode, sd->s_iattr);
+ } else
+ set_default_inode_attr(inode, mode);
+ }
+ return inode;
+}
+
+#ifdef CONFIG_LOCKDEP
+
+static void configfs_set_inode_lock_class(struct configfs_dirent *sd,
+ struct inode *inode)
+{
+ int depth = sd->s_depth;
+
+ if (depth > 0) {
+ if (depth <= ARRAY_SIZE(default_group_class)) {
+ 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.
+ */
+ pr_info("Too many levels of inodes for the locking correctness validator.\n");
+ pr_info("Spurious warnings may appear.\n");
+ }
+ }
+}
+
+#else /* CONFIG_LOCKDEP */
+
+static void configfs_set_inode_lock_class(struct configfs_dirent *sd,
+ struct inode *inode)
+{
+}
+
+#endif /* CONFIG_LOCKDEP */
+
+int configfs_create(struct dentry * dentry, umode_t mode, void (*init)(struct inode *))
+{
+ int error = 0;
+ struct inode *inode = NULL;
+ struct configfs_dirent *sd;
+ struct inode *p_inode;
+
+ if (!dentry)
+ return -ENOENT;
+
+ if (d_really_is_positive(dentry))
+ return -EEXIST;
+
+ sd = dentry->d_fsdata;
+ inode = configfs_new_inode(mode, sd, dentry->d_sb);
+ if (!inode)
+ return -ENOMEM;
+
+ p_inode = d_inode(dentry->d_parent);
+ p_inode->i_mtime = p_inode->i_ctime = current_time(p_inode);
+ configfs_set_inode_lock_class(sd, inode);
+
+ init(inode);
+ if (S_ISDIR(mode) || S_ISLNK(mode)) {
+ /*
+ * ->symlink(), ->mkdir(), configfs_register_subsystem() or
+ * create_default_group() - already hashed.
+ */
+ d_instantiate(dentry, inode);
+ dget(dentry); /* pin link and directory dentries in core */
+ } else {
+ /* ->lookup() */
+ d_add(dentry, inode);
+ }
+ return error;
+}
+
+/*
+ * Get the name for corresponding element represented by the given configfs_dirent
+ */
+const unsigned char * configfs_get_name(struct configfs_dirent *sd)
+{
+ struct configfs_attribute *attr;
+
+ BUG_ON(!sd || !sd->s_element);
+
+ /* These always have a dentry, so use that */
+ if (sd->s_type & (CONFIGFS_DIR | CONFIGFS_ITEM_LINK))
+ return sd->s_dentry->d_name.name;
+
+ if (sd->s_type & (CONFIGFS_ITEM_ATTR | CONFIGFS_ITEM_BIN_ATTR)) {
+ attr = sd->s_element;
+ return attr->ca_name;
+ }
+ return NULL;
+}
+
+
+/*
+ * Unhashes the dentry corresponding to given configfs_dirent
+ * Called with parent inode's i_mutex held.
+ */
+void configfs_drop_dentry(struct configfs_dirent * sd, struct dentry * parent)
+{
+ struct dentry * dentry = sd->s_dentry;
+
+ if (dentry) {
+ spin_lock(&dentry->d_lock);
+ if (simple_positive(dentry)) {
+ dget_dlock(dentry);
+ __d_drop(dentry);
+ spin_unlock(&dentry->d_lock);
+ simple_unlink(d_inode(parent), 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 (d_really_is_negative(dir))
+ /* no inode means this hasn't been made visible yet */
+ return;
+
+ inode_lock(d_inode(dir));
+ 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;
+ }
+ }
+ inode_unlock(d_inode(dir));
+}
diff --git a/fs/configfs/item.c b/fs/configfs/item.c
new file mode 100644
index 0000000..99d491c
--- /dev/null
+++ b/fs/configfs/item.c
@@ -0,0 +1,206 @@
+/* -*- mode: c; c-basic-offset: 8; -*-
+ * vim: noexpandtab sw=8 ts=8 sts=0:
+ *
+ * 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
+ *
+ * configfs Copyright (C) 2005 Oracle. All rights reserved.
+ *
+ * Please see the file Documentation/filesystems/configfs/configfs.txt for
+ * critical information about using the config_item interface.
+ */
+
+#include <linux/string.h>
+#include <linux/module.h>
+#include <linux/stat.h>
+#include <linux/slab.h>
+
+#include <linux/configfs.h>
+
+
+static inline struct config_item *to_item(struct list_head *entry)
+{
+ return container_of(entry, struct config_item, ci_entry);
+}
+
+/* Evil kernel */
+static void config_item_release(struct kref *kref);
+
+/**
+ * config_item_init - initialize item.
+ * @item: item in question.
+ */
+static void config_item_init(struct config_item *item)
+{
+ kref_init(&item->ci_kref);
+ INIT_LIST_HEAD(&item->ci_entry);
+}
+
+/**
+ * config_item_set_name - Set the name of an item
+ * @item: item.
+ * @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 limit = CONFIGFS_ITEM_NAME_LEN;
+ int need;
+ va_list args;
+ char *name;
+
+ /*
+ * First, try the static array
+ */
+ va_start(args, fmt);
+ need = vsnprintf(item->ci_namebuf, limit, fmt, args);
+ va_end(args);
+ if (need < limit)
+ name = item->ci_namebuf;
+ else {
+ va_start(args, fmt);
+ name = kvasprintf(GFP_KERNEL, fmt, args);
+ va_end(args);
+ if (!name)
+ return -EFAULT;
+ }
+
+ /* Free the old name, if necessary. */
+ if (item->ci_name && item->ci_name != item->ci_namebuf)
+ kfree(item->ci_name);
+
+ /* Now, set the new name */
+ item->ci_name = name;
+ return 0;
+}
+EXPORT_SYMBOL(config_item_set_name);
+
+void config_item_init_type_name(struct config_item *item,
+ const char *name,
+ const struct config_item_type *type)
+{
+ 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,
+ const struct config_item_type *type)
+{
+ 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)
+{
+ 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)
+{
+ 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));
+ if (item->ci_name != item->ci_namebuf)
+ kfree(item->ci_name);
+ item->ci_name = NULL;
+ if (t && t->ct_item_ops && t->ct_item_ops->release)
+ t->ct_item_ops->release(item);
+ if (s)
+ config_group_put(s);
+ if (parent)
+ config_item_put(parent);
+}
+
+static void config_item_release(struct kref *kref)
+{
+ config_item_cleanup(container_of(kref, struct config_item, ci_kref));
+}
+
+/**
+ * config_item_put - decrement refcount for item.
+ * @item: item.
+ *
+ * Decrement the refcount, and if 0, call config_item_cleanup().
+ */
+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
+ * @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.
+ * @group: group we're looking in.
+ * @name: item's name.
+ *
+ * Iterate over @group->cg_list, looking for a matching config_item.
+ * If matching item is found take a reference and return the item.
+ * Caller must have locked group via @group->cg_subsys->su_mtx.
+ */
+struct config_item *config_group_find_item(struct config_group *group,
+ const char *name)
+{
+ struct list_head *entry;
+ struct config_item *ret = NULL;
+
+ 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);
+ break;
+ }
+ }
+ return ret;
+}
+EXPORT_SYMBOL(config_group_find_item);
diff --git a/fs/configfs/mount.c b/fs/configfs/mount.c
new file mode 100644
index 0000000..cfd9132
--- /dev/null
+++ b/fs/configfs/mount.c
@@ -0,0 +1,175 @@
+/* -*- mode: c; c-basic-offset: 8; -*-
+ * vim: noexpandtab sw=8 ts=8 sts=0:
+ *
+ * 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
+ *
+ * configfs Copyright (C) 2005 Oracle. All rights reserved.
+ */
+
+#include <linux/fs.h>
+#include <linux/module.h>
+#include <linux/mount.h>
+#include <linux/pagemap.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+
+#include <linux/configfs.h>
+#include "configfs_internal.h"
+
+/* Random magic number */
+#define CONFIGFS_MAGIC 0x62656570
+
+static struct vfsmount *configfs_mount = NULL;
+struct kmem_cache *configfs_dir_cachep;
+static int configfs_mnt_count = 0;
+
+static const struct super_operations configfs_ops = {
+ .statfs = simple_statfs,
+ .drop_inode = generic_delete_inode,
+};
+
+static struct config_group configfs_root_group = {
+ .cg_item = {
+ .ci_namebuf = "root",
+ .ci_name = configfs_root_group.cg_item.ci_namebuf,
+ },
+};
+
+int configfs_is_root(struct config_item *item)
+{
+ return item == &configfs_root_group.cg_item;
+}
+
+static struct configfs_dirent configfs_root = {
+ .s_sibling = LIST_HEAD_INIT(configfs_root.s_sibling),
+ .s_children = LIST_HEAD_INIT(configfs_root.s_children),
+ .s_element = &configfs_root_group.cg_item,
+ .s_type = CONFIGFS_ROOT,
+ .s_iattr = NULL,
+};
+
+static int configfs_fill_super(struct super_block *sb, void *data, int silent)
+{
+ struct inode *inode;
+ struct dentry *root;
+
+ 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;
+
+ inode = configfs_new_inode(S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO,
+ &configfs_root, sb);
+ if (inode) {
+ inode->i_op = &configfs_root_inode_operations;
+ inode->i_fop = &configfs_dir_operations;
+ /* directory inodes start off with i_nlink == 2 (for "." entry) */
+ inc_nlink(inode);
+ } else {
+ pr_debug("could not get root inode\n");
+ return -ENOMEM;
+ }
+
+ root = d_make_root(inode);
+ if (!root) {
+ pr_debug("%s: could not get root dentry!\n",__func__);
+ return -ENOMEM;
+ }
+ config_group_init(&configfs_root_group);
+ 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 */
+ return 0;
+}
+
+static struct dentry *configfs_do_mount(struct file_system_type *fs_type,
+ int flags, const char *dev_name, void *data)
+{
+ return mount_single(fs_type, flags, data, configfs_fill_super);
+}
+
+static struct file_system_type configfs_fs_type = {
+ .owner = THIS_MODULE,
+ .name = "configfs",
+ .mount = configfs_do_mount,
+ .kill_sb = kill_litter_super,
+};
+MODULE_ALIAS_FS("configfs");
+
+struct dentry *configfs_pin_fs(void)
+{
+ int err = simple_pin_fs(&configfs_fs_type, &configfs_mount,
+ &configfs_mnt_count);
+ return err ? ERR_PTR(err) : configfs_mount->mnt_root;
+}
+
+void configfs_release_fs(void)
+{
+ simple_release_fs(&configfs_mount, &configfs_mnt_count);
+}
+
+
+static int __init configfs_init(void)
+{
+ int err = -ENOMEM;
+
+ configfs_dir_cachep = kmem_cache_create("configfs_dir_cache",
+ sizeof(struct configfs_dirent),
+ 0, 0, NULL);
+ if (!configfs_dir_cachep)
+ goto out;
+
+ err = sysfs_create_mount_point(kernel_kobj, "config");
+ if (err)
+ goto out2;
+
+ err = register_filesystem(&configfs_fs_type);
+ if (err)
+ goto out3;
+
+ return 0;
+out3:
+ 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;
+out:
+ return err;
+}
+
+static void __exit configfs_exit(void)
+{
+ unregister_filesystem(&configfs_fs_type);
+ sysfs_remove_mount_point(kernel_kobj, "config");
+ kmem_cache_destroy(configfs_dir_cachep);
+ configfs_dir_cachep = NULL;
+}
+
+MODULE_AUTHOR("Oracle");
+MODULE_LICENSE("GPL");
+MODULE_VERSION("0.0.2");
+MODULE_DESCRIPTION("Simple RAM filesystem for user driven kernel subsystem configuration.");
+
+core_initcall(configfs_init);
+module_exit(configfs_exit);
diff --git a/fs/configfs/symlink.c b/fs/configfs/symlink.c
new file mode 100644
index 0000000..a5c54af
--- /dev/null
+++ b/fs/configfs/symlink.c
@@ -0,0 +1,309 @@
+/* -*- mode: c; c-basic-offset: 8; -*-
+ * vim: noexpandtab sw=8 ts=8 sts=0:
+ *
+ * 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
+ *
+ * configfs Copyright (C) 2005 Oracle. All rights reserved.
+ */
+
+#include <linux/fs.h>
+#include <linux/module.h>
+#include <linux/namei.h>
+#include <linux/slab.h>
+
+#include <linux/configfs.h>
+#include "configfs_internal.h"
+
+/* Protects attachments of new symlinks */
+DEFINE_MUTEX(configfs_symlink_mutex);
+
+static int item_depth(struct config_item * item)
+{
+ struct config_item * p = item;
+ int depth = 0;
+ do { depth++; } while ((p = p->ci_parent) && !configfs_is_root(p));
+ return depth;
+}
+
+static int item_path_length(struct config_item * item)
+{
+ struct config_item * p = item;
+ int length = 1;
+ do {
+ length += strlen(config_item_name(p)) + 1;
+ p = p->ci_parent;
+ } while (p && !configfs_is_root(p));
+ return length;
+}
+
+static void fill_item_path(struct config_item * item, char * buffer, int length)
+{
+ struct config_item * p;
+
+ --length;
+ for (p = item; p && !configfs_is_root(p); p = p->ci_parent) {
+ int cur = strlen(config_item_name(p));
+
+ /* back up enough to print this bus id with '/' */
+ length -= cur;
+ memcpy(buffer + length, config_item_name(p), cur);
+ *(buffer + --length) = '/';
+ }
+}
+
+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;
+ 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) {
+ spin_lock(&configfs_dirent_lock);
+ if (target_sd->s_type & CONFIGFS_USET_DROPPING) {
+ spin_unlock(&configfs_dirent_lock);
+ kfree(sl);
+ return -ENOENT;
+ }
+ sl->sl_target = config_item_get(item);
+ list_add(&sl->sl_list, &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);
+ }
+ }
+
+out:
+ return ret;
+}
+
+
+static int get_target(const char *symname, struct path *path,
+ struct config_item **target, struct super_block *sb)
+{
+ 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;
+}
+
+
+int configfs_symlink(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;
+ 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;
+
+ parent_item = configfs_get_config_item(dentry->d_parent);
+ type = parent_item->ci_type;
+
+ ret = -EPERM;
+ if (!type || !type->ct_item_ops ||
+ !type->ct_item_ops->allow_link)
+ goto out_put;
+
+ ret = get_target(symname, &path, &target_item, dentry->d_sb);
+ if (ret)
+ goto out_put;
+
+ 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);
+ mutex_unlock(&configfs_symlink_mutex);
+ if (ret && type->ct_item_ops->drop_link)
+ type->ct_item_ops->drop_link(parent_item,
+ target_item);
+ }
+
+ 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 config_item *parent_item;
+ 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;
+
+ parent_item = configfs_get_config_item(dentry->d_parent);
+ type = parent_item->ci_type;
+
+ spin_lock(&configfs_dirent_lock);
+ list_del_init(&sd->s_sibling);
+ spin_unlock(&configfs_dirent_lock);
+ configfs_drop_dentry(sd, dentry->d_parent);
+ dput(dentry);
+ configfs_put(sd);
+
+ /*
+ * drop_link() must be called before
+ * list_del_init(&sl->sl_list), 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);
+
+ spin_lock(&configfs_dirent_lock);
+ list_del_init(&sl->sl_list);
+ spin_unlock(&configfs_dirent_lock);
+
+ /* Put reference from create_link() */
+ config_item_put(sl->sl_target);
+ kfree(sl);
+
+ config_item_put(parent_item);
+
+ ret = 0;
+
+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 const char *configfs_get_link(struct dentry *dentry,
+ struct inode *inode,
+ struct delayed_call *done)
+{
+ char *body;
+ int error;
+
+ if (!dentry)
+ return ERR_PTR(-ECHILD);
+
+ body = kzalloc(PAGE_SIZE, GFP_KERNEL);
+ if (!body)
+ return ERR_PTR(-ENOMEM);
+
+ error = configfs_getlink(dentry, body);
+ if (!error) {
+ set_delayed_call(done, kfree_link, body);
+ return body;
+ }
+
+ kfree(body);
+ return ERR_PTR(error);
+}
+
+const struct inode_operations configfs_symlink_inode_operations = {
+ .get_link = configfs_get_link,
+ .setattr = configfs_setattr,
+};
+