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01c4ac1315
o Created dmfs.h as a private header for the filesystem code o Using seq_file.[ch] written by Al Viro as a generic mechanism for /proc style files which have one record per line. We use a slight modification here, so if you are using a recent -ac kernel you'll need to replace the existing seq_file.[ch] with the ones here and do a bit of editing to make it work. I'll submit the changes to Al Viro shortly as they are very small and I think make sense generally. o Using fail_writepage() o Init code for filesystem now all in dmfs-super.c o Some common code reduction amoung the dmfs-*.c files o Auto allocation of major device number (default). You can specify a particular major by using a module argument. If built in then you don't get this option at the moment but it could be added if required. o Hotplug support o General tidying o Updated projects.txt file o Patches updated to 2.4.14
159 lines
3.6 KiB
C
159 lines
3.6 KiB
C
/*
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* dmfs-root.c
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*
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* Copyright (C) 2001 Sistina Software
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*
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* This software is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2, or (at
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* your option) any later version.
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*
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* This software 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
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* GNU 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 License
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* along with GNU CC; see the file COPYING. If not, write to
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* the Free Software Foundation, 59 Temple Place - Suite 330,
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* Boston, MA 02111-1307, USA.
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*/
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/* Heavily based upon ramfs */
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#include <linux/config.h>
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#include <linux/ctype.h>
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#include <linux/fs.h>
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#include "dm.h"
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#include "dmfs.h"
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extern struct inode *dmfs_create_lv(struct super_block *sb, int mode, struct dentry *dentry);
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static int is_identifier(const char *str, int len)
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{
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while(len--) {
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if (!isalnum(*str) && *str != '_')
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return 0;
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str++;
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}
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return 1;
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}
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static int dmfs_root_mkdir(struct inode *dir, struct dentry *dentry, int mode)
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{
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struct inode *inode;
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int rv = -ENOSPC;
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if (dentry->d_name.len >= DM_NAME_LEN)
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return -EINVAL;
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if (!is_identifier(dentry->d_name.name, dentry->d_name.len))
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return -EPERM;
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if (dentry->d_name.name[0] == '.')
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return -EINVAL;
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inode = dmfs_create_lv(dir->i_sb, mode, dentry);
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if (inode) {
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d_instantiate(dentry, inode);
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dget(dentry);
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rv = 0;
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}
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return rv;
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}
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/*
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* if u.generic_ip is not NULL, then it indicates an inode which
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* represents a table. If it is NULL then the inode is a virtual
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* file and should be deleted along with the directory.
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*/
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static inline int positive(struct dentry *dentry)
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{
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return dentry->d_inode && !d_unhashed(dentry);
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}
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static int empty(struct dentry *dentry)
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{
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struct list_head *list;
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spin_lock(&dcache_lock);
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list = dentry->d_subdirs.next;
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while(list != &dentry->d_subdirs) {
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struct dentry *de = list_entry(list, struct dentry, d_child);
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if (positive(de)) {
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spin_unlock(&dcache_lock);
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return 0;
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}
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list = list->next;
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}
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spin_unlock(&dcache_lock);
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return 1;
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}
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static int dmfs_root_rmdir(struct inode *dir, struct dentry *dentry)
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{
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int ret = -ENOTEMPTY;
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if (empty(dentry)) {
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struct inode *inode = dentry->d_inode;
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ret = dm_deactivate(DMFS_I(inode)->md);
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if (ret == 0) {
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inode->i_nlink--;
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dput(dentry);
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}
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}
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return ret;
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}
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static struct dentry *dmfs_root_lookup(struct inode *dir, struct dentry *dentry)
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{
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d_add(dentry, NULL);
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return NULL;
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}
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static int dmfs_root_rename(struct inode *old_dir, struct dentry *old_dentry,
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struct inode *new_dir, struct dentry *new_dentry)
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{
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/* Can only rename - not move between directories! */
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if (old_dir != new_dir)
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return -EPERM;
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return -EINVAL; /* FIXME: a change of LV name here */
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}
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static int dmfs_root_sync(struct file *file, struct dentry *dentry, int datasync)
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{
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return 0;
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}
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static struct file_operations dmfs_root_file_operations = {
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read: generic_read_dir,
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readdir: dcache_readdir,
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fsync: dmfs_root_sync,
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};
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static struct inode_operations dmfs_root_inode_operations = {
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lookup: dmfs_root_lookup,
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mkdir: dmfs_root_mkdir,
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rmdir: dmfs_root_rmdir,
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rename: dmfs_root_rename,
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};
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struct inode *dmfs_create_root(struct super_block *sb, int mode)
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{
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struct inode *inode = dmfs_new_inode(sb, mode | S_IFDIR);
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if (inode) {
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inode->i_fop = &dmfs_root_file_operations;
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inode->i_op = &dmfs_root_inode_operations;
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}
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return inode;
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}
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