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163 lines
4.1 KiB
C
163 lines
4.1 KiB
C
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/* -*- mode: c; c-basic-offset: 8; -*-
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* vim: noexpandtab sw=8 ts=8 sts=0:
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*
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* inode.c - basic inode and dentry operations.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public
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* License along with this program; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 021110-1307, USA.
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*
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* Based on sysfs:
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* sysfs is Copyright (C) 2001, 2002, 2003 Patrick Mochel
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*
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* configfs Copyright (C) 2005 Oracle. All rights reserved.
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*
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* Please see Documentation/filesystems/configfs.txt for more information.
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*/
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#undef DEBUG
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#include <linux/pagemap.h>
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#include <linux/namei.h>
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#include <linux/backing-dev.h>
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#include <linux/configfs.h>
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#include "configfs_internal.h"
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extern struct super_block * configfs_sb;
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static struct address_space_operations configfs_aops = {
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.readpage = simple_readpage,
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.prepare_write = simple_prepare_write,
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.commit_write = simple_commit_write
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};
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static struct backing_dev_info configfs_backing_dev_info = {
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.ra_pages = 0, /* No readahead */
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.capabilities = BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK,
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};
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struct inode * configfs_new_inode(mode_t mode)
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{
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struct inode * inode = new_inode(configfs_sb);
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if (inode) {
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inode->i_mode = mode;
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inode->i_uid = 0;
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inode->i_gid = 0;
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inode->i_blksize = PAGE_CACHE_SIZE;
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inode->i_blocks = 0;
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inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
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inode->i_mapping->a_ops = &configfs_aops;
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inode->i_mapping->backing_dev_info = &configfs_backing_dev_info;
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}
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return inode;
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}
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int configfs_create(struct dentry * dentry, int mode, int (*init)(struct inode *))
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{
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int error = 0;
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struct inode * inode = NULL;
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if (dentry) {
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if (!dentry->d_inode) {
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if ((inode = configfs_new_inode(mode))) {
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if (dentry->d_parent && dentry->d_parent->d_inode) {
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struct inode *p_inode = dentry->d_parent->d_inode;
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p_inode->i_mtime = p_inode->i_ctime = CURRENT_TIME;
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}
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goto Proceed;
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}
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else
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error = -ENOMEM;
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} else
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error = -EEXIST;
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} else
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error = -ENOENT;
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goto Done;
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Proceed:
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if (init)
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error = init(inode);
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if (!error) {
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d_instantiate(dentry, inode);
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if (S_ISDIR(mode) || S_ISLNK(mode))
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dget(dentry); /* pin link and directory dentries in core */
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} else
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iput(inode);
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Done:
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return error;
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}
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/*
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* Get the name for corresponding element represented by the given configfs_dirent
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*/
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const unsigned char * configfs_get_name(struct configfs_dirent *sd)
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{
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struct attribute * attr;
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if (!sd || !sd->s_element)
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BUG();
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/* These always have a dentry, so use that */
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if (sd->s_type & (CONFIGFS_DIR | CONFIGFS_ITEM_LINK))
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return sd->s_dentry->d_name.name;
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if (sd->s_type & CONFIGFS_ITEM_ATTR) {
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attr = sd->s_element;
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return attr->name;
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}
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return NULL;
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}
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/*
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* Unhashes the dentry corresponding to given configfs_dirent
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* Called with parent inode's i_sem held.
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*/
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void configfs_drop_dentry(struct configfs_dirent * sd, struct dentry * parent)
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{
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struct dentry * dentry = sd->s_dentry;
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if (dentry) {
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spin_lock(&dcache_lock);
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if (!(d_unhashed(dentry) && dentry->d_inode)) {
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dget_locked(dentry);
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__d_drop(dentry);
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spin_unlock(&dcache_lock);
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simple_unlink(parent->d_inode, dentry);
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} else
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spin_unlock(&dcache_lock);
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}
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}
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void configfs_hash_and_remove(struct dentry * dir, const char * name)
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{
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struct configfs_dirent * sd;
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struct configfs_dirent * parent_sd = dir->d_fsdata;
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down(&dir->d_inode->i_sem);
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list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
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if (!sd->s_element)
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continue;
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if (!strcmp(configfs_get_name(sd), name)) {
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list_del_init(&sd->s_sibling);
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configfs_drop_dentry(sd, dir);
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configfs_put(sd);
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break;
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}
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}
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up(&dir->d_inode->i_sem);
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}
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