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50f3074011
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
1007 lines
21 KiB
C
1007 lines
21 KiB
C
/*
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* Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
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* Licensed under the GPL
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*
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* Ported the filesystem routines to 2.5.
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* 2003-02-10 Petr Baudis <pasky@ucw.cz>
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*/
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#include <linux/fs.h>
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#include <linux/magic.h>
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#include <linux/module.h>
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#include <linux/mm.h>
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#include <linux/pagemap.h>
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#include <linux/statfs.h>
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#include <linux/slab.h>
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#include <linux/seq_file.h>
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#include <linux/mount.h>
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#include <linux/namei.h>
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#include "hostfs.h"
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#include <init.h>
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#include <kern.h>
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struct hostfs_inode_info {
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int fd;
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fmode_t mode;
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struct inode vfs_inode;
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struct mutex open_mutex;
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};
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static inline struct hostfs_inode_info *HOSTFS_I(struct inode *inode)
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{
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return list_entry(inode, struct hostfs_inode_info, vfs_inode);
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}
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#define FILE_HOSTFS_I(file) HOSTFS_I(file_inode(file))
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/* Changed in hostfs_args before the kernel starts running */
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static char *root_ino = "";
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static int append = 0;
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static const struct inode_operations hostfs_iops;
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static const struct inode_operations hostfs_dir_iops;
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static const struct inode_operations hostfs_link_iops;
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#ifndef MODULE
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static int __init hostfs_args(char *options, int *add)
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{
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char *ptr;
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ptr = strchr(options, ',');
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if (ptr != NULL)
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*ptr++ = '\0';
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if (*options != '\0')
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root_ino = options;
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options = ptr;
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while (options) {
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ptr = strchr(options, ',');
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if (ptr != NULL)
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*ptr++ = '\0';
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if (*options != '\0') {
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if (!strcmp(options, "append"))
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append = 1;
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else printf("hostfs_args - unsupported option - %s\n",
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options);
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}
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options = ptr;
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}
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return 0;
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}
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__uml_setup("hostfs=", hostfs_args,
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"hostfs=<root dir>,<flags>,...\n"
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" This is used to set hostfs parameters. The root directory argument\n"
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" is used to confine all hostfs mounts to within the specified directory\n"
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" tree on the host. If this isn't specified, then a user inside UML can\n"
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" mount anything on the host that's accessible to the user that's running\n"
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" it.\n"
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" The only flag currently supported is 'append', which specifies that all\n"
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" files opened by hostfs will be opened in append mode.\n\n"
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);
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#endif
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static char *__dentry_name(struct dentry *dentry, char *name)
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{
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char *p = dentry_path_raw(dentry, name, PATH_MAX);
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char *root;
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size_t len;
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root = dentry->d_sb->s_fs_info;
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len = strlen(root);
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if (IS_ERR(p)) {
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__putname(name);
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return NULL;
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}
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/*
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* This function relies on the fact that dentry_path_raw() will place
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* the path name at the end of the provided buffer.
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*/
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BUG_ON(p + strlen(p) + 1 != name + PATH_MAX);
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strlcpy(name, root, PATH_MAX);
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if (len > p - name) {
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__putname(name);
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return NULL;
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}
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if (p > name + len)
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strcpy(name + len, p);
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return name;
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}
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static char *dentry_name(struct dentry *dentry)
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{
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char *name = __getname();
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if (!name)
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return NULL;
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return __dentry_name(dentry, name);
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}
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static char *inode_name(struct inode *ino)
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{
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struct dentry *dentry;
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char *name;
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dentry = d_find_alias(ino);
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if (!dentry)
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return NULL;
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name = dentry_name(dentry);
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dput(dentry);
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return name;
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}
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static char *follow_link(char *link)
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{
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int len, n;
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char *name, *resolved, *end;
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name = __getname();
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if (!name) {
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n = -ENOMEM;
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goto out_free;
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}
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n = hostfs_do_readlink(link, name, PATH_MAX);
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if (n < 0)
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goto out_free;
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else if (n == PATH_MAX) {
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n = -E2BIG;
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goto out_free;
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}
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if (*name == '/')
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return name;
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end = strrchr(link, '/');
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if (end == NULL)
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return name;
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*(end + 1) = '\0';
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len = strlen(link) + strlen(name) + 1;
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resolved = kmalloc(len, GFP_KERNEL);
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if (resolved == NULL) {
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n = -ENOMEM;
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goto out_free;
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}
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sprintf(resolved, "%s%s", link, name);
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__putname(name);
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kfree(link);
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return resolved;
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out_free:
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__putname(name);
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return ERR_PTR(n);
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}
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static struct inode *hostfs_iget(struct super_block *sb)
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{
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struct inode *inode = new_inode(sb);
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if (!inode)
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return ERR_PTR(-ENOMEM);
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return inode;
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}
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static int hostfs_statfs(struct dentry *dentry, struct kstatfs *sf)
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{
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/*
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* do_statfs uses struct statfs64 internally, but the linux kernel
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* struct statfs still has 32-bit versions for most of these fields,
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* so we convert them here
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*/
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int err;
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long long f_blocks;
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long long f_bfree;
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long long f_bavail;
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long long f_files;
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long long f_ffree;
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err = do_statfs(dentry->d_sb->s_fs_info,
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&sf->f_bsize, &f_blocks, &f_bfree, &f_bavail, &f_files,
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&f_ffree, &sf->f_fsid, sizeof(sf->f_fsid),
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&sf->f_namelen);
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if (err)
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return err;
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sf->f_blocks = f_blocks;
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sf->f_bfree = f_bfree;
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sf->f_bavail = f_bavail;
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sf->f_files = f_files;
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sf->f_ffree = f_ffree;
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sf->f_type = HOSTFS_SUPER_MAGIC;
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return 0;
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}
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static struct inode *hostfs_alloc_inode(struct super_block *sb)
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{
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struct hostfs_inode_info *hi;
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hi = kmalloc(sizeof(*hi), GFP_KERNEL_ACCOUNT);
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if (hi == NULL)
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return NULL;
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hi->fd = -1;
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hi->mode = 0;
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inode_init_once(&hi->vfs_inode);
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mutex_init(&hi->open_mutex);
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return &hi->vfs_inode;
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}
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static void hostfs_evict_inode(struct inode *inode)
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{
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truncate_inode_pages_final(&inode->i_data);
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clear_inode(inode);
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if (HOSTFS_I(inode)->fd != -1) {
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close_file(&HOSTFS_I(inode)->fd);
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HOSTFS_I(inode)->fd = -1;
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}
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}
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static void hostfs_i_callback(struct rcu_head *head)
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{
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struct inode *inode = container_of(head, struct inode, i_rcu);
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kfree(HOSTFS_I(inode));
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}
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static void hostfs_destroy_inode(struct inode *inode)
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{
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call_rcu(&inode->i_rcu, hostfs_i_callback);
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}
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static int hostfs_show_options(struct seq_file *seq, struct dentry *root)
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{
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const char *root_path = root->d_sb->s_fs_info;
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size_t offset = strlen(root_ino) + 1;
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if (strlen(root_path) > offset)
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seq_show_option(seq, root_path + offset, NULL);
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if (append)
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seq_puts(seq, ",append");
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return 0;
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}
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static const struct super_operations hostfs_sbops = {
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.alloc_inode = hostfs_alloc_inode,
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.destroy_inode = hostfs_destroy_inode,
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.evict_inode = hostfs_evict_inode,
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.statfs = hostfs_statfs,
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.show_options = hostfs_show_options,
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};
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static int hostfs_readdir(struct file *file, struct dir_context *ctx)
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{
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void *dir;
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char *name;
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unsigned long long next, ino;
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int error, len;
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unsigned int type;
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name = dentry_name(file->f_path.dentry);
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if (name == NULL)
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return -ENOMEM;
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dir = open_dir(name, &error);
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__putname(name);
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if (dir == NULL)
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return -error;
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next = ctx->pos;
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seek_dir(dir, next);
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while ((name = read_dir(dir, &next, &ino, &len, &type)) != NULL) {
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if (!dir_emit(ctx, name, len, ino, type))
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break;
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ctx->pos = next;
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}
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close_dir(dir);
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return 0;
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}
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static int hostfs_open(struct inode *ino, struct file *file)
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{
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char *name;
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fmode_t mode;
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int err;
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int r, w, fd;
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mode = file->f_mode & (FMODE_READ | FMODE_WRITE);
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if ((mode & HOSTFS_I(ino)->mode) == mode)
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return 0;
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mode |= HOSTFS_I(ino)->mode;
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retry:
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r = w = 0;
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if (mode & FMODE_READ)
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r = 1;
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if (mode & FMODE_WRITE)
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r = w = 1;
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name = dentry_name(file->f_path.dentry);
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if (name == NULL)
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return -ENOMEM;
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fd = open_file(name, r, w, append);
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__putname(name);
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if (fd < 0)
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return fd;
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mutex_lock(&HOSTFS_I(ino)->open_mutex);
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/* somebody else had handled it first? */
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if ((mode & HOSTFS_I(ino)->mode) == mode) {
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mutex_unlock(&HOSTFS_I(ino)->open_mutex);
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close_file(&fd);
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return 0;
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}
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if ((mode | HOSTFS_I(ino)->mode) != mode) {
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mode |= HOSTFS_I(ino)->mode;
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mutex_unlock(&HOSTFS_I(ino)->open_mutex);
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close_file(&fd);
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goto retry;
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}
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if (HOSTFS_I(ino)->fd == -1) {
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HOSTFS_I(ino)->fd = fd;
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} else {
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err = replace_file(fd, HOSTFS_I(ino)->fd);
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close_file(&fd);
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if (err < 0) {
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mutex_unlock(&HOSTFS_I(ino)->open_mutex);
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return err;
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}
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}
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HOSTFS_I(ino)->mode = mode;
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mutex_unlock(&HOSTFS_I(ino)->open_mutex);
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return 0;
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}
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static int hostfs_file_release(struct inode *inode, struct file *file)
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{
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filemap_write_and_wait(inode->i_mapping);
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return 0;
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}
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static int hostfs_fsync(struct file *file, loff_t start, loff_t end,
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int datasync)
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{
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struct inode *inode = file->f_mapping->host;
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int ret;
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ret = file_write_and_wait_range(file, start, end);
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if (ret)
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return ret;
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inode_lock(inode);
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ret = fsync_file(HOSTFS_I(inode)->fd, datasync);
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inode_unlock(inode);
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return ret;
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}
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static const struct file_operations hostfs_file_fops = {
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.llseek = generic_file_llseek,
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.splice_read = generic_file_splice_read,
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.read_iter = generic_file_read_iter,
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.write_iter = generic_file_write_iter,
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.mmap = generic_file_mmap,
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.open = hostfs_open,
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.release = hostfs_file_release,
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.fsync = hostfs_fsync,
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};
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static const struct file_operations hostfs_dir_fops = {
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.llseek = generic_file_llseek,
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.iterate_shared = hostfs_readdir,
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.read = generic_read_dir,
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.open = hostfs_open,
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.fsync = hostfs_fsync,
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};
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static int hostfs_writepage(struct page *page, struct writeback_control *wbc)
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{
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struct address_space *mapping = page->mapping;
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struct inode *inode = mapping->host;
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char *buffer;
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loff_t base = page_offset(page);
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int count = PAGE_SIZE;
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int end_index = inode->i_size >> PAGE_SHIFT;
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int err;
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if (page->index >= end_index)
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count = inode->i_size & (PAGE_SIZE-1);
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buffer = kmap(page);
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err = write_file(HOSTFS_I(inode)->fd, &base, buffer, count);
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if (err != count) {
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ClearPageUptodate(page);
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goto out;
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}
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if (base > inode->i_size)
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inode->i_size = base;
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if (PageError(page))
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ClearPageError(page);
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err = 0;
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out:
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kunmap(page);
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unlock_page(page);
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return err;
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}
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static int hostfs_readpage(struct file *file, struct page *page)
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{
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char *buffer;
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loff_t start = page_offset(page);
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int bytes_read, ret = 0;
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buffer = kmap(page);
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bytes_read = read_file(FILE_HOSTFS_I(file)->fd, &start, buffer,
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PAGE_SIZE);
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if (bytes_read < 0) {
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ClearPageUptodate(page);
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SetPageError(page);
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ret = bytes_read;
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goto out;
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}
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memset(buffer + bytes_read, 0, PAGE_SIZE - bytes_read);
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ClearPageError(page);
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SetPageUptodate(page);
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out:
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flush_dcache_page(page);
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kunmap(page);
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unlock_page(page);
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return ret;
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}
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static int hostfs_write_begin(struct file *file, struct address_space *mapping,
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loff_t pos, unsigned len, unsigned flags,
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struct page **pagep, void **fsdata)
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{
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pgoff_t index = pos >> PAGE_SHIFT;
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*pagep = grab_cache_page_write_begin(mapping, index, flags);
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if (!*pagep)
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return -ENOMEM;
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return 0;
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}
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static int hostfs_write_end(struct file *file, struct address_space *mapping,
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loff_t pos, unsigned len, unsigned copied,
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struct page *page, void *fsdata)
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{
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struct inode *inode = mapping->host;
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void *buffer;
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unsigned from = pos & (PAGE_SIZE - 1);
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int err;
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buffer = kmap(page);
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err = write_file(FILE_HOSTFS_I(file)->fd, &pos, buffer + from, copied);
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kunmap(page);
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if (!PageUptodate(page) && err == PAGE_SIZE)
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SetPageUptodate(page);
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/*
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* If err > 0, write_file has added err to pos, so we are comparing
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* i_size against the last byte written.
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*/
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if (err > 0 && (pos > inode->i_size))
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inode->i_size = pos;
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unlock_page(page);
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put_page(page);
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return err;
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}
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static const struct address_space_operations hostfs_aops = {
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.writepage = hostfs_writepage,
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.readpage = hostfs_readpage,
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.set_page_dirty = __set_page_dirty_nobuffers,
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.write_begin = hostfs_write_begin,
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.write_end = hostfs_write_end,
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};
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static int read_name(struct inode *ino, char *name)
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{
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dev_t rdev;
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struct hostfs_stat st;
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int err = stat_file(name, &st, -1);
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if (err)
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return err;
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/* Reencode maj and min with the kernel encoding.*/
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rdev = MKDEV(st.maj, st.min);
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switch (st.mode & S_IFMT) {
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case S_IFLNK:
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ino->i_op = &hostfs_link_iops;
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break;
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case S_IFDIR:
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ino->i_op = &hostfs_dir_iops;
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ino->i_fop = &hostfs_dir_fops;
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break;
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case S_IFCHR:
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case S_IFBLK:
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case S_IFIFO:
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case S_IFSOCK:
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init_special_inode(ino, st.mode & S_IFMT, rdev);
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ino->i_op = &hostfs_iops;
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break;
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case S_IFREG:
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ino->i_op = &hostfs_iops;
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ino->i_fop = &hostfs_file_fops;
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ino->i_mapping->a_ops = &hostfs_aops;
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break;
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default:
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return -EIO;
|
|
}
|
|
|
|
ino->i_ino = st.ino;
|
|
ino->i_mode = st.mode;
|
|
set_nlink(ino, st.nlink);
|
|
i_uid_write(ino, st.uid);
|
|
i_gid_write(ino, st.gid);
|
|
ino->i_atime = timespec_to_timespec64(st.atime);
|
|
ino->i_mtime = timespec_to_timespec64(st.mtime);
|
|
ino->i_ctime = timespec_to_timespec64(st.ctime);
|
|
ino->i_size = st.size;
|
|
ino->i_blocks = st.blocks;
|
|
return 0;
|
|
}
|
|
|
|
static int hostfs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
|
|
bool excl)
|
|
{
|
|
struct inode *inode;
|
|
char *name;
|
|
int error, fd;
|
|
|
|
inode = hostfs_iget(dir->i_sb);
|
|
if (IS_ERR(inode)) {
|
|
error = PTR_ERR(inode);
|
|
goto out;
|
|
}
|
|
|
|
error = -ENOMEM;
|
|
name = dentry_name(dentry);
|
|
if (name == NULL)
|
|
goto out_put;
|
|
|
|
fd = file_create(name, mode & 0777);
|
|
if (fd < 0)
|
|
error = fd;
|
|
else
|
|
error = read_name(inode, name);
|
|
|
|
__putname(name);
|
|
if (error)
|
|
goto out_put;
|
|
|
|
HOSTFS_I(inode)->fd = fd;
|
|
HOSTFS_I(inode)->mode = FMODE_READ | FMODE_WRITE;
|
|
d_instantiate(dentry, inode);
|
|
return 0;
|
|
|
|
out_put:
|
|
iput(inode);
|
|
out:
|
|
return error;
|
|
}
|
|
|
|
static struct dentry *hostfs_lookup(struct inode *ino, struct dentry *dentry,
|
|
unsigned int flags)
|
|
{
|
|
struct inode *inode;
|
|
char *name;
|
|
int err;
|
|
|
|
inode = hostfs_iget(ino->i_sb);
|
|
if (IS_ERR(inode))
|
|
goto out;
|
|
|
|
err = -ENOMEM;
|
|
name = dentry_name(dentry);
|
|
if (name) {
|
|
err = read_name(inode, name);
|
|
__putname(name);
|
|
}
|
|
if (err) {
|
|
iput(inode);
|
|
inode = (err == -ENOENT) ? NULL : ERR_PTR(err);
|
|
}
|
|
out:
|
|
return d_splice_alias(inode, dentry);
|
|
}
|
|
|
|
static int hostfs_link(struct dentry *to, struct inode *ino,
|
|
struct dentry *from)
|
|
{
|
|
char *from_name, *to_name;
|
|
int err;
|
|
|
|
if ((from_name = dentry_name(from)) == NULL)
|
|
return -ENOMEM;
|
|
to_name = dentry_name(to);
|
|
if (to_name == NULL) {
|
|
__putname(from_name);
|
|
return -ENOMEM;
|
|
}
|
|
err = link_file(to_name, from_name);
|
|
__putname(from_name);
|
|
__putname(to_name);
|
|
return err;
|
|
}
|
|
|
|
static int hostfs_unlink(struct inode *ino, struct dentry *dentry)
|
|
{
|
|
char *file;
|
|
int err;
|
|
|
|
if (append)
|
|
return -EPERM;
|
|
|
|
if ((file = dentry_name(dentry)) == NULL)
|
|
return -ENOMEM;
|
|
|
|
err = unlink_file(file);
|
|
__putname(file);
|
|
return err;
|
|
}
|
|
|
|
static int hostfs_symlink(struct inode *ino, struct dentry *dentry,
|
|
const char *to)
|
|
{
|
|
char *file;
|
|
int err;
|
|
|
|
if ((file = dentry_name(dentry)) == NULL)
|
|
return -ENOMEM;
|
|
err = make_symlink(file, to);
|
|
__putname(file);
|
|
return err;
|
|
}
|
|
|
|
static int hostfs_mkdir(struct inode *ino, struct dentry *dentry, umode_t mode)
|
|
{
|
|
char *file;
|
|
int err;
|
|
|
|
if ((file = dentry_name(dentry)) == NULL)
|
|
return -ENOMEM;
|
|
err = do_mkdir(file, mode);
|
|
__putname(file);
|
|
return err;
|
|
}
|
|
|
|
static int hostfs_rmdir(struct inode *ino, struct dentry *dentry)
|
|
{
|
|
char *file;
|
|
int err;
|
|
|
|
if ((file = dentry_name(dentry)) == NULL)
|
|
return -ENOMEM;
|
|
err = hostfs_do_rmdir(file);
|
|
__putname(file);
|
|
return err;
|
|
}
|
|
|
|
static int hostfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t dev)
|
|
{
|
|
struct inode *inode;
|
|
char *name;
|
|
int err;
|
|
|
|
inode = hostfs_iget(dir->i_sb);
|
|
if (IS_ERR(inode)) {
|
|
err = PTR_ERR(inode);
|
|
goto out;
|
|
}
|
|
|
|
err = -ENOMEM;
|
|
name = dentry_name(dentry);
|
|
if (name == NULL)
|
|
goto out_put;
|
|
|
|
init_special_inode(inode, mode, dev);
|
|
err = do_mknod(name, mode, MAJOR(dev), MINOR(dev));
|
|
if (err)
|
|
goto out_free;
|
|
|
|
err = read_name(inode, name);
|
|
__putname(name);
|
|
if (err)
|
|
goto out_put;
|
|
|
|
d_instantiate(dentry, inode);
|
|
return 0;
|
|
|
|
out_free:
|
|
__putname(name);
|
|
out_put:
|
|
iput(inode);
|
|
out:
|
|
return err;
|
|
}
|
|
|
|
static int hostfs_rename2(struct inode *old_dir, struct dentry *old_dentry,
|
|
struct inode *new_dir, struct dentry *new_dentry,
|
|
unsigned int flags)
|
|
{
|
|
char *old_name, *new_name;
|
|
int err;
|
|
|
|
if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE))
|
|
return -EINVAL;
|
|
|
|
old_name = dentry_name(old_dentry);
|
|
if (old_name == NULL)
|
|
return -ENOMEM;
|
|
new_name = dentry_name(new_dentry);
|
|
if (new_name == NULL) {
|
|
__putname(old_name);
|
|
return -ENOMEM;
|
|
}
|
|
if (!flags)
|
|
err = rename_file(old_name, new_name);
|
|
else
|
|
err = rename2_file(old_name, new_name, flags);
|
|
|
|
__putname(old_name);
|
|
__putname(new_name);
|
|
return err;
|
|
}
|
|
|
|
static int hostfs_permission(struct inode *ino, int desired)
|
|
{
|
|
char *name;
|
|
int r = 0, w = 0, x = 0, err;
|
|
|
|
if (desired & MAY_NOT_BLOCK)
|
|
return -ECHILD;
|
|
|
|
if (desired & MAY_READ) r = 1;
|
|
if (desired & MAY_WRITE) w = 1;
|
|
if (desired & MAY_EXEC) x = 1;
|
|
name = inode_name(ino);
|
|
if (name == NULL)
|
|
return -ENOMEM;
|
|
|
|
if (S_ISCHR(ino->i_mode) || S_ISBLK(ino->i_mode) ||
|
|
S_ISFIFO(ino->i_mode) || S_ISSOCK(ino->i_mode))
|
|
err = 0;
|
|
else
|
|
err = access_file(name, r, w, x);
|
|
__putname(name);
|
|
if (!err)
|
|
err = generic_permission(ino, desired);
|
|
return err;
|
|
}
|
|
|
|
static int hostfs_setattr(struct dentry *dentry, struct iattr *attr)
|
|
{
|
|
struct inode *inode = d_inode(dentry);
|
|
struct hostfs_iattr attrs;
|
|
char *name;
|
|
int err;
|
|
|
|
int fd = HOSTFS_I(inode)->fd;
|
|
|
|
err = setattr_prepare(dentry, attr);
|
|
if (err)
|
|
return err;
|
|
|
|
if (append)
|
|
attr->ia_valid &= ~ATTR_SIZE;
|
|
|
|
attrs.ia_valid = 0;
|
|
if (attr->ia_valid & ATTR_MODE) {
|
|
attrs.ia_valid |= HOSTFS_ATTR_MODE;
|
|
attrs.ia_mode = attr->ia_mode;
|
|
}
|
|
if (attr->ia_valid & ATTR_UID) {
|
|
attrs.ia_valid |= HOSTFS_ATTR_UID;
|
|
attrs.ia_uid = from_kuid(&init_user_ns, attr->ia_uid);
|
|
}
|
|
if (attr->ia_valid & ATTR_GID) {
|
|
attrs.ia_valid |= HOSTFS_ATTR_GID;
|
|
attrs.ia_gid = from_kgid(&init_user_ns, attr->ia_gid);
|
|
}
|
|
if (attr->ia_valid & ATTR_SIZE) {
|
|
attrs.ia_valid |= HOSTFS_ATTR_SIZE;
|
|
attrs.ia_size = attr->ia_size;
|
|
}
|
|
if (attr->ia_valid & ATTR_ATIME) {
|
|
attrs.ia_valid |= HOSTFS_ATTR_ATIME;
|
|
attrs.ia_atime = timespec64_to_timespec(attr->ia_atime);
|
|
}
|
|
if (attr->ia_valid & ATTR_MTIME) {
|
|
attrs.ia_valid |= HOSTFS_ATTR_MTIME;
|
|
attrs.ia_mtime = timespec64_to_timespec(attr->ia_mtime);
|
|
}
|
|
if (attr->ia_valid & ATTR_CTIME) {
|
|
attrs.ia_valid |= HOSTFS_ATTR_CTIME;
|
|
attrs.ia_ctime = timespec64_to_timespec(attr->ia_ctime);
|
|
}
|
|
if (attr->ia_valid & ATTR_ATIME_SET) {
|
|
attrs.ia_valid |= HOSTFS_ATTR_ATIME_SET;
|
|
}
|
|
if (attr->ia_valid & ATTR_MTIME_SET) {
|
|
attrs.ia_valid |= HOSTFS_ATTR_MTIME_SET;
|
|
}
|
|
name = dentry_name(dentry);
|
|
if (name == NULL)
|
|
return -ENOMEM;
|
|
err = set_attr(name, &attrs, fd);
|
|
__putname(name);
|
|
if (err)
|
|
return err;
|
|
|
|
if ((attr->ia_valid & ATTR_SIZE) &&
|
|
attr->ia_size != i_size_read(inode))
|
|
truncate_setsize(inode, attr->ia_size);
|
|
|
|
setattr_copy(inode, attr);
|
|
mark_inode_dirty(inode);
|
|
return 0;
|
|
}
|
|
|
|
static const struct inode_operations hostfs_iops = {
|
|
.permission = hostfs_permission,
|
|
.setattr = hostfs_setattr,
|
|
};
|
|
|
|
static const struct inode_operations hostfs_dir_iops = {
|
|
.create = hostfs_create,
|
|
.lookup = hostfs_lookup,
|
|
.link = hostfs_link,
|
|
.unlink = hostfs_unlink,
|
|
.symlink = hostfs_symlink,
|
|
.mkdir = hostfs_mkdir,
|
|
.rmdir = hostfs_rmdir,
|
|
.mknod = hostfs_mknod,
|
|
.rename = hostfs_rename2,
|
|
.permission = hostfs_permission,
|
|
.setattr = hostfs_setattr,
|
|
};
|
|
|
|
static const char *hostfs_get_link(struct dentry *dentry,
|
|
struct inode *inode,
|
|
struct delayed_call *done)
|
|
{
|
|
char *link;
|
|
if (!dentry)
|
|
return ERR_PTR(-ECHILD);
|
|
link = kmalloc(PATH_MAX, GFP_KERNEL);
|
|
if (link) {
|
|
char *path = dentry_name(dentry);
|
|
int err = -ENOMEM;
|
|
if (path) {
|
|
err = hostfs_do_readlink(path, link, PATH_MAX);
|
|
if (err == PATH_MAX)
|
|
err = -E2BIG;
|
|
__putname(path);
|
|
}
|
|
if (err < 0) {
|
|
kfree(link);
|
|
return ERR_PTR(err);
|
|
}
|
|
} else {
|
|
return ERR_PTR(-ENOMEM);
|
|
}
|
|
|
|
set_delayed_call(done, kfree_link, link);
|
|
return link;
|
|
}
|
|
|
|
static const struct inode_operations hostfs_link_iops = {
|
|
.get_link = hostfs_get_link,
|
|
};
|
|
|
|
static int hostfs_fill_sb_common(struct super_block *sb, void *d, int silent)
|
|
{
|
|
struct inode *root_inode;
|
|
char *host_root_path, *req_root = d;
|
|
int err;
|
|
|
|
sb->s_blocksize = 1024;
|
|
sb->s_blocksize_bits = 10;
|
|
sb->s_magic = HOSTFS_SUPER_MAGIC;
|
|
sb->s_op = &hostfs_sbops;
|
|
sb->s_d_op = &simple_dentry_operations;
|
|
sb->s_maxbytes = MAX_LFS_FILESIZE;
|
|
|
|
/* NULL is printed as <NULL> by sprintf: avoid that. */
|
|
if (req_root == NULL)
|
|
req_root = "";
|
|
|
|
err = -ENOMEM;
|
|
sb->s_fs_info = host_root_path =
|
|
kmalloc(strlen(root_ino) + strlen(req_root) + 2, GFP_KERNEL);
|
|
if (host_root_path == NULL)
|
|
goto out;
|
|
|
|
sprintf(host_root_path, "%s/%s", root_ino, req_root);
|
|
|
|
root_inode = new_inode(sb);
|
|
if (!root_inode)
|
|
goto out;
|
|
|
|
err = read_name(root_inode, host_root_path);
|
|
if (err)
|
|
goto out_put;
|
|
|
|
if (S_ISLNK(root_inode->i_mode)) {
|
|
char *name = follow_link(host_root_path);
|
|
if (IS_ERR(name)) {
|
|
err = PTR_ERR(name);
|
|
goto out_put;
|
|
}
|
|
err = read_name(root_inode, name);
|
|
kfree(name);
|
|
if (err)
|
|
goto out_put;
|
|
}
|
|
|
|
err = -ENOMEM;
|
|
sb->s_root = d_make_root(root_inode);
|
|
if (sb->s_root == NULL)
|
|
goto out;
|
|
|
|
return 0;
|
|
|
|
out_put:
|
|
iput(root_inode);
|
|
out:
|
|
return err;
|
|
}
|
|
|
|
static struct dentry *hostfs_read_sb(struct file_system_type *type,
|
|
int flags, const char *dev_name,
|
|
void *data)
|
|
{
|
|
return mount_nodev(type, flags, data, hostfs_fill_sb_common);
|
|
}
|
|
|
|
static void hostfs_kill_sb(struct super_block *s)
|
|
{
|
|
kill_anon_super(s);
|
|
kfree(s->s_fs_info);
|
|
}
|
|
|
|
static struct file_system_type hostfs_type = {
|
|
.owner = THIS_MODULE,
|
|
.name = "hostfs",
|
|
.mount = hostfs_read_sb,
|
|
.kill_sb = hostfs_kill_sb,
|
|
.fs_flags = 0,
|
|
};
|
|
MODULE_ALIAS_FS("hostfs");
|
|
|
|
static int __init init_hostfs(void)
|
|
{
|
|
return register_filesystem(&hostfs_type);
|
|
}
|
|
|
|
static void __exit exit_hostfs(void)
|
|
{
|
|
unregister_filesystem(&hostfs_type);
|
|
}
|
|
|
|
module_init(init_hostfs)
|
|
module_exit(exit_hostfs)
|
|
MODULE_LICENSE("GPL");
|