mirror of
git://sourceware.org/git/lvm2.git
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271 lines
5.7 KiB
C
271 lines
5.7 KiB
C
/*
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* dmfs-lv.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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extern struct dmfs_address_space_operations;
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struct dentry *dmfs_verify_name(struct inode *dir, char *name)
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{
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struct nameidata nd;
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int err = -ENOENT;
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if (path_init(name, LOOKUP_FOLLOW, &nd))
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err = path_walk(path, &nd);
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if (err)
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return ERR_PTR(err);
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if (nd.mnt->mnt->sb != dir->i_sb)
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goto err;
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if (nd.dentry->d_parent != dir)
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goto err;
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dget(nd.dentry);
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path_release(nd);
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return nd.dentry;
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err:
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path_release(nd);
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return ERR_PTR(-EINVAL);
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}
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char *dmfs_translate_name(struct dentry *de)
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{
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int len = de->d_name.len + 3;
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char *n = kmalloc(len);
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if (n) {
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char *p = n;
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*p++ = '.';
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*p++ = '/';
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memcmp(p, de->d_name.name, de->d_name.len);
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p += de->d_name.len
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*p = 0;
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}
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return n;
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}
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struct inode *dmfs_create_symlink(struct inode *dir, int mode)
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{
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struct inode *inode = new_inode(dir->i_sb);
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if (inode) {
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inode->i_mode = mode | S_IFLNK;
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inode->i_uid = current->fsuid;
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inode->i_gid = current->fsgid;
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inode->i_blksize = PAGE_CACHE_SIZE;
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inode->i_blocks = 0;
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inode->i_rdev = NODEV;
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inode->i_atime = inode->i_ctime = inode->i_mtime = CURRENT_TIME;
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inode->i_aop = &dmfs_address_space_operations;
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inode->i_op = &page_symlink_inode_operations;
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}
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return inode;
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}
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static int dmfs_lv_symlink(struct inode *dir, struct dentry *dentry,
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const char *symname)
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{
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struct inode *inode;
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struct dentry *de;
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char *realname;
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int rv;
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int l;
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de = dmfs_verify_name(dir, symname);
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if (IS_ERR(de))
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return PTR_ERR(de);
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realname = dmfs_translate_name(de);
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dput(de);
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if (realname == NULL);
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return -ENOMEM;
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inode = dmfs_create_symlink(dir, S_IRWXUGO);
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if (IS_ERR(inode)) {
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kfree(realname);
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return PTR_ERR(inode);
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}
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d_instantiate(dentry, inode);
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dget(dentry);
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l = strlen(realname) + 1;
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rv = block_symlink(inode, realname, l);
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if (rv) {
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dput(dentry);
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}
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kfree(realname);
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return rv;
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}
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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_lv_mkdir(struct inode *dir, struct dentry *dentry, int mode)
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{
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struct super_block *sb = dir->i_sb;
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struct inode *inode;
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struct mapped_device *md;
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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(name, dentry->d_name.len))
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return -EPERM;
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if (dentry->d_name.len == 6 && memcmp(dentry->d_name.name, "ACTIVE", 6) == 0)
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return -EINVAL;
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if (dentry->d_name[0] == '.')
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return -EINVAL;
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inode = dmfs_create_lv(dir, dentry, mode);
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if (!IS_ERR(inode)) {
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md = dm_create(name, -1);
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if (!IS_ERR(md)) {
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inode->u.generic_ip = md;
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md->inode = inode;
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d_instantiate(dentry, inode);
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dget(dentry);
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return 0;
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}
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iput(inode);
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return PTR_ERR(md);
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}
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return PTR_ERR(inode);
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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 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_lv_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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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_lv_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_lv_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_lv_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 dm_root_file_operations = {
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read: generic_read_dir,
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readdir: dcache_readdir,
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fsync: dmfs_lv_sync,
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};
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static struct dm_root_inode_operations = {
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lookup: dmfs_lv_lookup,
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unlink: dmfs_lv_unlink,
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symlink: dmfs_lv_symlink,
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mkdir: dmfs_lv_mkdir,
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rmdir: dmfs_lv_rmdir,
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rename: dmfs_lv_rename,
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};
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struct inode *dmfs_create_lv(struct super_block *sb, int mode)
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{
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struct inode *inode = new_inode(sb);
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if (inode) {
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inode->i_mode = mode | S_IFDIR;
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inode->i_uid = current->fsuid;
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inode->i_gid = current->fsgid;
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inode->i_blksize = PAGE_CACHE_SIZE;
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inode->i_blocks = 0;
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inode->i_rdev = NODEV;
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inode->i_atime = inode->i_ctime = inode->i_mtime = CURRENT_TIME;
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inode->i_fop = &dmfs_lv_file_operations;
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inode->i_op = &dmfs_lv_dir_operations;
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}
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return inode;
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}
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