--- /dev/null
+/* -*- 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;
+ 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 = timespec_trunc(iattr->ia_atime,
+ inode->i_sb->s_time_gran);
+ if (ia_valid & ATTR_MTIME)
+ sd_iattr->ia_mtime = timespec_trunc(iattr->ia_mtime,
+ inode->i_sb->s_time_gran);
+ if (ia_valid & ATTR_CTIME)
+ sd_iattr->ia_ctime = timespec_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;
+}
+
+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_mutex,
+ &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;
+ configfs_set_inode_lock_class(sd, inode);
+
+ init(inode);
+ d_instantiate(dentry, inode);
+ if (S_ISDIR(mode) || S_ISLNK(mode))
+ dget(dentry); /* pin link and directory dentries in core */
+ 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) {
+ 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 (!d_unhashed(dentry) && d_really_is_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;
+
+ mutex_lock(&d_inode(dir)->i_mutex);
+ list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
+ if (!sd->s_element)
+ continue;
+ if (!strcmp(configfs_get_name(sd), name)) {
+ spin_lock(&configfs_dirent_lock);
+ list_del_init(&sd->s_sibling);
+ spin_unlock(&configfs_dirent_lock);
+ configfs_drop_dentry(sd, dir);
+ configfs_put(sd);
+ break;
+ }
+ }
+ mutex_unlock(&d_inode(dir)->i_mutex);
+}
Code Review / kvmfornfv.git / blobdiff