diff options
Diffstat (limited to 'fs/hostfs/hostfs_kern.c')
| -rw-r--r-- | fs/hostfs/hostfs_kern.c | 1045 |
1 files changed, 1045 insertions, 0 deletions
diff --git a/fs/hostfs/hostfs_kern.c b/fs/hostfs/hostfs_kern.c new file mode 100644 index 000000000000..a88ad2924851 --- /dev/null +++ b/fs/hostfs/hostfs_kern.c @@ -0,0 +1,1045 @@ +/* + * Copyright (C) 2000, 2001, 2002 Jeff Dike (jdike@karaya.com) + * Licensed under the GPL + * + * Ported the filesystem routines to 2.5. + * 2003-02-10 Petr Baudis <pasky@ucw.cz> + */ + +#include <linux/stddef.h> +#include <linux/fs.h> +#include <linux/version.h> +#include <linux/module.h> +#include <linux/init.h> +#include <linux/slab.h> +#include <linux/pagemap.h> +#include <linux/blkdev.h> +#include <linux/list.h> +#include <linux/root_dev.h> +#include <linux/statfs.h> +#include <linux/kdev_t.h> +#include <asm/uaccess.h> +#include "hostfs.h" +#include "kern_util.h" +#include "kern.h" +#include "user_util.h" +#include "2_5compat.h" +#include "init.h" + +struct hostfs_inode_info { + char *host_filename; + int fd; + int mode; + struct inode vfs_inode; +}; + +static inline struct hostfs_inode_info *HOSTFS_I(struct inode *inode) +{ + return(list_entry(inode, struct hostfs_inode_info, vfs_inode)); +} + +#define FILE_HOSTFS_I(file) HOSTFS_I((file)->f_dentry->d_inode) + +int hostfs_d_delete(struct dentry *dentry) +{ + return(1); +} + +struct dentry_operations hostfs_dentry_ops = { + .d_delete = hostfs_d_delete, +}; + +/* Changed in hostfs_args before the kernel starts running */ +static char *root_ino = "/"; +static int append = 0; + +#define HOSTFS_SUPER_MAGIC 0x00c0ffee + +static struct inode_operations hostfs_iops; +static struct inode_operations hostfs_dir_iops; +static struct address_space_operations hostfs_link_aops; + +#ifndef MODULE +static int __init hostfs_args(char *options, int *add) +{ + char *ptr; + + ptr = strchr(options, ','); + if(ptr != NULL) + *ptr++ = '\0'; + if(*options != '\0') + root_ino = options; + + options = ptr; + while(options){ + ptr = strchr(options, ','); + if(ptr != NULL) + *ptr++ = '\0'; + if(*options != '\0'){ + if(!strcmp(options, "append")) + append = 1; + else printf("hostfs_args - unsupported option - %s\n", + options); + } + options = ptr; + } + return(0); +} + +__uml_setup("hostfs=", hostfs_args, +"hostfs=<root dir>,<flags>,...\n" +" This is used to set hostfs parameters. The root directory argument\n" +" is used to confine all hostfs mounts to within the specified directory\n" +" tree on the host. If this isn't specified, then a user inside UML can\n" +" mount anything on the host that's accessible to the user that's running\n" +" it.\n" +" The only flag currently supported is 'append', which specifies that all\n" +" files opened by hostfs will be opened in append mode.\n\n" +); +#endif + +static char *dentry_name(struct dentry *dentry, int extra) +{ + struct dentry *parent; + char *root, *name; + int len; + + len = 0; + parent = dentry; + while(parent->d_parent != parent){ + len += parent->d_name.len + 1; + parent = parent->d_parent; + } + + root = HOSTFS_I(parent->d_inode)->host_filename; + len += strlen(root); + name = kmalloc(len + extra + 1, GFP_KERNEL); + if(name == NULL) return(NULL); + + name[len] = '\0'; + parent = dentry; + while(parent->d_parent != parent){ + len -= parent->d_name.len + 1; + name[len] = '/'; + strncpy(&name[len + 1], parent->d_name.name, + parent->d_name.len); + parent = parent->d_parent; + } + strncpy(name, root, strlen(root)); + return(name); +} + +static char *inode_name(struct inode *ino, int extra) +{ + struct dentry *dentry; + + dentry = list_entry(ino->i_dentry.next, struct dentry, d_alias); + return(dentry_name(dentry, extra)); +} + +static int read_name(struct inode *ino, char *name) +{ + /* The non-int inode fields are copied into ints by stat_file and + * then copied into the inode because passing the actual pointers + * in and having them treated as int * breaks on big-endian machines + */ + int err; + int i_mode, i_nlink, i_blksize; + unsigned long long i_size; + unsigned long long i_ino; + unsigned long long i_blocks; + + err = stat_file(name, &i_ino, &i_mode, &i_nlink, &ino->i_uid, + &ino->i_gid, &i_size, &ino->i_atime, &ino->i_mtime, + &ino->i_ctime, &i_blksize, &i_blocks); + if(err) + return(err); + + ino->i_ino = i_ino; + ino->i_mode = i_mode; + ino->i_nlink = i_nlink; + ino->i_size = i_size; + ino->i_blksize = i_blksize; + ino->i_blocks = i_blocks; + if((ino->i_sb->s_dev == ROOT_DEV) && (ino->i_uid == getuid())) + ino->i_uid = 0; + return(0); +} + +static char *follow_link(char *link) +{ + int len, n; + char *name, *resolved, *end; + + len = 64; + while(1){ + n = -ENOMEM; + name = kmalloc(len, GFP_KERNEL); + if(name == NULL) + goto out; + + n = do_readlink(link, name, len); + if(n < len) + break; + len *= 2; + kfree(name); + } + if(n < 0) + goto out_free; + + if(*name == '/') + return(name); + + end = strrchr(link, '/'); + if(end == NULL) + return(name); + + *(end + 1) = '\0'; + len = strlen(link) + strlen(name) + 1; + + resolved = kmalloc(len, GFP_KERNEL); + if(resolved == NULL){ + n = -ENOMEM; + goto out_free; + } + + sprintf(resolved, "%s%s", link, name); + kfree(name); + kfree(link); + return(resolved); + + out_free: + kfree(name); + out: + return(ERR_PTR(n)); +} + +static int read_inode(struct inode *ino) +{ + char *name; + int err = 0; + + /* Unfortunately, we are called from iget() when we don't have a dentry + * allocated yet. + */ + if(list_empty(&ino->i_dentry)) + goto out; + + err = -ENOMEM; + name = inode_name(ino, 0); + if(name == NULL) + goto out; + + if(file_type(name, NULL, NULL) == OS_TYPE_SYMLINK){ + name = follow_link(name); + if(IS_ERR(name)){ + err = PTR_ERR(name); + goto out; + } + } + + err = read_name(ino, name); + kfree(name); + out: + return(err); +} + +int hostfs_statfs(struct super_block *sb, struct kstatfs *sf) +{ + /* do_statfs uses struct statfs64 internally, but the linux kernel + * struct statfs still has 32-bit versions for most of these fields, + * so we convert them here + */ + int err; + long long f_blocks; + long long f_bfree; + long long f_bavail; + long long f_files; + long long f_ffree; + + err = do_statfs(HOSTFS_I(sb->s_root->d_inode)->host_filename, + &sf->f_bsize, &f_blocks, &f_bfree, &f_bavail, &f_files, + &f_ffree, &sf->f_fsid, sizeof(sf->f_fsid), + &sf->f_namelen, sf->f_spare); + if(err) return(err); + sf->f_blocks = f_blocks; + sf->f_bfree = f_bfree; + sf->f_bavail = f_bavail; + sf->f_files = f_files; + sf->f_ffree = f_ffree; + sf->f_type = HOSTFS_SUPER_MAGIC; + return(0); +} + +static struct inode *hostfs_alloc_inode(struct super_block *sb) +{ + struct hostfs_inode_info *hi; + + hi = kmalloc(sizeof(*hi), GFP_KERNEL); + if(hi == NULL) + return(NULL); + + *hi = ((struct hostfs_inode_info) { .host_filename = NULL, + .fd = -1, + .mode = 0 }); + inode_init_once(&hi->vfs_inode); + return(&hi->vfs_inode); +} + +static void hostfs_delete_inode(struct inode *inode) +{ + if(HOSTFS_I(inode)->fd != -1) { + close_file(&HOSTFS_I(inode)->fd); + HOSTFS_I(inode)->fd = -1; + } + clear_inode(inode); +} + +static void hostfs_destroy_inode(struct inode *inode) +{ + if(HOSTFS_I(inode)->host_filename) + kfree(HOSTFS_I(inode)->host_filename); + + /*XXX: This should not happen, probably. The check is here for + * additional safety.*/ + if(HOSTFS_I(inode)->fd != -1) { + close_file(&HOSTFS_I(inode)->fd); + printk(KERN_DEBUG "Closing host fd in .destroy_inode\n"); + } + + kfree(HOSTFS_I(inode)); +} + +static void hostfs_read_inode(struct inode *inode) +{ + read_inode(inode); +} + +static struct super_operations hostfs_sbops = { + .alloc_inode = hostfs_alloc_inode, + .drop_inode = generic_delete_inode, + .delete_inode = hostfs_delete_inode, + .destroy_inode = hostfs_destroy_inode, + .read_inode = hostfs_read_inode, + .statfs = hostfs_statfs, +}; + +int hostfs_readdir(struct file *file, void *ent, filldir_t filldir) +{ + void *dir; + char *name; + unsigned long long next, ino; + int error, len; + + name = dentry_name(file->f_dentry, 0); + if(name == NULL) return(-ENOMEM); + dir = open_dir(name, &error); + kfree(name); + if(dir == NULL) return(-error); + next = file->f_pos; + while((name = read_dir(dir, &next, &ino, &len)) != NULL){ + error = (*filldir)(ent, name, len, file->f_pos, + ino, DT_UNKNOWN); + if(error) break; + file->f_pos = next; + } + close_dir(dir); + return(0); +} + +int hostfs_file_open(struct inode *ino, struct file *file) +{ + char *name; + int mode = 0, r = 0, w = 0, fd; + + mode = file->f_mode & (FMODE_READ | FMODE_WRITE); + if((mode & HOSTFS_I(ino)->mode) == mode) + return(0); + + /* The file may already have been opened, but with the wrong access, + * so this resets things and reopens the file with the new access. + */ + if(HOSTFS_I(ino)->fd != -1){ + close_file(&HOSTFS_I(ino)->fd); + HOSTFS_I(ino)->fd = -1; + } + + HOSTFS_I(ino)->mode |= mode; + if(HOSTFS_I(ino)->mode & FMODE_READ) + r = 1; + if(HOSTFS_I(ino)->mode & FMODE_WRITE) + w = 1; + if(w) + r = 1; + + name = dentry_name(file->f_dentry, 0); + if(name == NULL) + return(-ENOMEM); + + fd = open_file(name, r, w, append); + kfree(name); + if(fd < 0) return(fd); + FILE_HOSTFS_I(file)->fd = fd; + + return(0); +} + +int hostfs_fsync(struct file *file, struct dentry *dentry, int datasync) +{ + return(0); +} + +static struct file_operations hostfs_file_fops = { + .llseek = generic_file_llseek, + .read = generic_file_read, + .sendfile = generic_file_sendfile, + .aio_read = generic_file_aio_read, + .aio_write = generic_file_aio_write, + .readv = generic_file_readv, + .writev = generic_file_writev, + .write = generic_file_write, + .mmap = generic_file_mmap, + .open = hostfs_file_open, + .release = NULL, + .fsync = hostfs_fsync, +}; + +static struct file_operations hostfs_dir_fops = { + .llseek = generic_file_llseek, + .readdir = hostfs_readdir, + .read = generic_read_dir, +}; + +int hostfs_writepage(struct page *page, struct writeback_control *wbc) +{ + struct address_space *mapping = page->mapping; + struct inode *inode = mapping->host; + char *buffer; + unsigned long long base; + int count = PAGE_CACHE_SIZE; + int end_index = inode->i_size >> PAGE_CACHE_SHIFT; + int err; + + if (page->index >= end_index) + count = inode->i_size & (PAGE_CACHE_SIZE-1); + + buffer = kmap(page); + base = ((unsigned long long) page->index) << PAGE_CACHE_SHIFT; + + err = write_file(HOSTFS_I(inode)->fd, &base, buffer, count); + if(err != count){ + ClearPageUptodate(page); + goto out; + } + + if (base > inode->i_size) + inode->i_size = base; + + if (PageError(page)) + ClearPageError(page); + err = 0; + + out: + kunmap(page); + + unlock_page(page); + return err; +} + +int hostfs_readpage(struct file *file, struct page *page) +{ + char *buffer; + long long start; + int err = 0; + + start = (long long) page->index << PAGE_CACHE_SHIFT; + buffer = kmap(page); + err = read_file(FILE_HOSTFS_I(file)->fd, &start, buffer, + PAGE_CACHE_SIZE); + if(err < 0) goto out; + + memset(&buffer[err], 0, PAGE_CACHE_SIZE - err); + + flush_dcache_page(page); + SetPageUptodate(page); + if (PageError(page)) ClearPageError(page); + err = 0; + out: + kunmap(page); + unlock_page(page); + return(err); +} + +int hostfs_prepare_write(struct file *file, struct page *page, + unsigned int from, unsigned int to) +{ + char *buffer; + long long start, tmp; + int err; + + start = (long long) page->index << PAGE_CACHE_SHIFT; + buffer = kmap(page); + if(from != 0){ + tmp = start; + err = read_file(FILE_HOSTFS_I(file)->fd, &tmp, buffer, + from); + if(err < 0) goto out; + } + if(to != PAGE_CACHE_SIZE){ + start += to; + err = read_file(FILE_HOSTFS_I(file)->fd, &start, buffer + to, + PAGE_CACHE_SIZE - to); + if(err < 0) goto out; + } + err = 0; + out: + kunmap(page); + return(err); +} + +int hostfs_commit_write(struct file *file, struct page *page, unsigned from, + unsigned to) +{ + struct address_space *mapping = page->mapping; + struct inode *inode = mapping->host; + char *buffer; + long long start; + int err = 0; + + start = (long long) (page->index << PAGE_CACHE_SHIFT) + from; + buffer = kmap(page); + err = write_file(FILE_HOSTFS_I(file)->fd, &start, buffer + from, + to - from); + if(err > 0) err = 0; + if(!err && (start > inode->i_size)) + inode->i_size = start; + + kunmap(page); + return(err); +} + +static struct address_space_operations hostfs_aops = { + .writepage = hostfs_writepage, + .readpage = hostfs_readpage, +/* .set_page_dirty = __set_page_dirty_nobuffers, */ + .prepare_write = hostfs_prepare_write, + .commit_write = hostfs_commit_write +}; + +static int init_inode(struct inode *inode, struct dentry *dentry) +{ + char *name; + int type, err = -ENOMEM; + int maj, min; + dev_t rdev = 0; + + if(dentry){ + name = dentry_name(dentry, 0); + if(name == NULL) + goto out; + type = file_type(name, &maj, &min); + /*Reencode maj and min with the kernel encoding.*/ + rdev = MKDEV(maj, min); + kfree(name); + } + else type = OS_TYPE_DIR; + + err = 0; + if(type == OS_TYPE_SYMLINK) + inode->i_op = &page_symlink_inode_operations; + else if(type == OS_TYPE_DIR) + inode->i_op = &hostfs_dir_iops; + else inode->i_op = &hostfs_iops; + + if(type == OS_TYPE_DIR) inode->i_fop = &hostfs_dir_fops; + else inode->i_fop = &hostfs_file_fops; + + if(type == OS_TYPE_SYMLINK) + inode->i_mapping->a_ops = &hostfs_link_aops; + else inode->i_mapping->a_ops = &hostfs_aops; + + switch (type) { + case OS_TYPE_CHARDEV: + init_special_inode(inode, S_IFCHR, rdev); + break; + case OS_TYPE_BLOCKDEV: + init_special_inode(inode, S_IFBLK, rdev); + break; + case OS_TYPE_FIFO: + init_special_inode(inode, S_IFIFO, 0); + break; + case OS_TYPE_SOCK: + init_special_inode(inode, S_IFSOCK, 0); + break; + } + out: + return(err); +} + +int hostfs_create(struct inode *dir, struct dentry *dentry, int mode, + struct nameidata *nd) +{ + struct inode *inode; + char *name; + int error, fd; + + error = -ENOMEM; + inode = iget(dir->i_sb, 0); + if(inode == NULL) goto out; + + error = init_inode(inode, dentry); + if(error) + goto out_put; + + error = -ENOMEM; + name = dentry_name(dentry, 0); + if(name == NULL) + goto out_put; + + fd = file_create(name, + mode & S_IRUSR, mode & S_IWUSR, mode & S_IXUSR, + mode & S_IRGRP, mode & S_IWGRP, mode & S_IXGRP, + mode & S_IROTH, mode & S_IWOTH, mode & S_IXOTH); + if(fd < 0) + error = fd; + else error = read_name(inode, name); + + kfree(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); +} + +struct dentry *hostfs_lookup(struct inode *ino, struct dentry *dentry, + struct nameidata *nd) +{ + struct inode *inode; + char *name; + int err; + + err = -ENOMEM; + inode = iget(ino->i_sb, 0); + if(inode == NULL) + goto out; + + err = init_inode(inode, dentry); + if(err) + goto out_put; + + err = -ENOMEM; + name = dentry_name(dentry, 0); + if(name == NULL) + goto out_put; + + err = read_name(inode, name); + kfree(name); + if(err == -ENOENT){ + iput(inode); + inode = NULL; + } + else if(err) + goto out_put; + + d_add(dentry, inode); + dentry->d_op = &hostfs_dentry_ops; + return(NULL); + + out_put: + iput(inode); + out: + return(ERR_PTR(err)); +} + +static char *inode_dentry_name(struct inode *ino, struct dentry *dentry) +{ + char *file; + int len; + + file = inode_name(ino, dentry->d_name.len + 1); + if(file == NULL) return(NULL); + strcat(file, "/"); + len = strlen(file); + strncat(file, dentry->d_name.name, dentry->d_name.len); + file[len + dentry->d_name.len] = '\0'; + return(file); +} + +int hostfs_link(struct dentry *to, struct inode *ino, struct dentry *from) +{ + char *from_name, *to_name; + int err; + + if((from_name = inode_dentry_name(ino, from)) == NULL) + return(-ENOMEM); + to_name = dentry_name(to, 0); + if(to_name == NULL){ + kfree(from_name); + return(-ENOMEM); + } + err = link_file(to_name, from_name); + kfree(from_name); + kfree(to_name); + return(err); +} + +int hostfs_unlink(struct inode *ino, struct dentry *dentry) +{ + char *file; + int err; + + if((file = inode_dentry_name(ino, dentry)) == NULL) return(-ENOMEM); + if(append) + return(-EPERM); + + err = unlink_file(file); + kfree(file); + return(err); +} + +int hostfs_symlink(struct inode *ino, struct dentry *dentry, const char *to) +{ + char *file; + int err; + + if((file = inode_dentry_name(ino, dentry)) == NULL) return(-ENOMEM); + err = make_symlink(file, to); + kfree(file); + return(err); +} + +int hostfs_mkdir(struct inode *ino, struct dentry *dentry, int mode) +{ + char *file; + int err; + + if((file = inode_dentry_name(ino, dentry)) == NULL) return(-ENOMEM); + err = do_mkdir(file, mode); + kfree(file); + return(err); +} + +int hostfs_rmdir(struct inode *ino, struct dentry *dentry) +{ + char *file; + int err; + + if((file = inode_dentry_name(ino, dentry)) == NULL) return(-ENOMEM); + err = do_rmdir(file); + kfree(file); + return(err); +} + +int hostfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev) +{ + struct inode *inode; + char *name; + int err = -ENOMEM; + + inode = iget(dir->i_sb, 0); + if(inode == NULL) + goto out; + + err = init_inode(inode, dentry); + if(err) + goto out_put; + + err = -ENOMEM; + name = dentry_name(dentry, 0); + if(name == NULL) + goto out_put; + + init_special_inode(inode, mode, dev); + err = do_mknod(name, mode, dev); + if(err) + goto out_free; + + err = read_name(inode, name); + kfree(name); + if(err) + goto out_put; + + d_instantiate(dentry, inode); + return(0); + + out_free: + kfree(name); + out_put: + iput(inode); + out: + return(err); +} + +int hostfs_rename(struct inode *from_ino, struct dentry *from, + struct inode *to_ino, struct dentry *to) +{ + char *from_name, *to_name; + int err; + + if((from_name = inode_dentry_name(from_ino, from)) == NULL) + return(-ENOMEM); + if((to_name = inode_dentry_name(to_ino, to)) == NULL){ + kfree(from_name); + return(-ENOMEM); + } + err = rename_file(from_name, to_name); + kfree(from_name); + kfree(to_name); + return(err); +} + +void hostfs_truncate(struct inode *ino) +{ + not_implemented(); +} + +int hostfs_permission(struct inode *ino, int desired, struct nameidata *nd) +{ + char *name; + int r = 0, w = 0, x = 0, err; + + if (desired & MAY_READ) r = 1; + if (desired & MAY_WRITE) w = 1; + if (desired & MAY_EXEC) x = 1; + name = inode_name(ino, 0); + 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); + kfree(name); + if(!err) + err = generic_permission(ino, desired, NULL); + return err; +} + +int hostfs_setattr(struct dentry *dentry, struct iattr *attr) +{ + struct hostfs_iattr attrs; + char *name; + int err; + + err = inode_change_ok(dentry->d_inode, 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){ + if((dentry->d_inode->i_sb->s_dev == ROOT_DEV) && + (attr->ia_uid == 0)) + attr->ia_uid = getuid(); + attrs.ia_valid |= HOSTFS_ATTR_UID; + attrs.ia_uid = attr->ia_uid; + } + if(attr->ia_valid & ATTR_GID){ + if((dentry->d_inode->i_sb->s_dev == ROOT_DEV) && + (attr->ia_gid == 0)) + attr->ia_gid = getgid(); + attrs.ia_valid |= HOSTFS_ATTR_GID; + attrs.ia_gid = 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 = attr->ia_atime; + } + if(attr->ia_valid & ATTR_MTIME){ + attrs.ia_valid |= HOSTFS_ATTR_MTIME; + attrs.ia_mtime = attr->ia_mtime; + } + if(attr->ia_valid & ATTR_CTIME){ + attrs.ia_valid |= HOSTFS_ATTR_CTIME; + attrs.ia_ctime = 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, 0); + if(name == NULL) return(-ENOMEM); + err = set_attr(name, &attrs); + kfree(name); + if(err) + return(err); + + return(inode_setattr(dentry->d_inode, attr)); +} + +int hostfs_getattr(struct vfsmount *mnt, struct dentry *dentry, + struct kstat *stat) +{ + generic_fillattr(dentry->d_inode, stat); + return(0); +} + +static struct inode_operations hostfs_iops = { + .create = hostfs_create, + .link = hostfs_link, + .unlink = hostfs_unlink, + .symlink = hostfs_symlink, + .mkdir = hostfs_mkdir, + .rmdir = hostfs_rmdir, + .mknod = hostfs_mknod, + .rename = hostfs_rename, + .truncate = hostfs_truncate, + .permission = hostfs_permission, + .setattr = hostfs_setattr, + .getattr = hostfs_getattr, +}; + +static 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_rename, + .truncate = hostfs_truncate, + .permission = hostfs_permission, + .setattr = hostfs_setattr, + .getattr = hostfs_getattr, +}; + +int hostfs_link_readpage(struct file *file, struct page *page) +{ + char *buffer, *name; + long long start; + int err; + + start = page->index << PAGE_CACHE_SHIFT; + buffer = kmap(page); + name = inode_name(page->mapping->host, 0); + if(name == NULL) return(-ENOMEM); + err = do_readlink(name, buffer, PAGE_CACHE_SIZE); + kfree(name); + if(err == PAGE_CACHE_SIZE) + err = -E2BIG; + else if(err > 0){ + flush_dcache_page(page); + SetPageUptodate(page); + if (PageError(page)) ClearPageError(page); + err = 0; + } + kunmap(page); + unlock_page(page); + return(err); +} + +static struct address_space_operations hostfs_link_aops = { + .readpage = hostfs_link_readpage, +}; + +static int hostfs_fill_sb_common(struct super_block *sb, void *d, int silent) +{ + struct inode *root_inode; + char *name, *data = d; + int err; + + sb->s_blocksize = 1024; + sb->s_blocksize_bits = 10; + sb->s_magic = HOSTFS_SUPER_MAGIC; + sb->s_op = &hostfs_sbops; + + if((data == NULL) || (*data == '\0')) + data = root_ino; + + err = -ENOMEM; + name = kmalloc(strlen(data) + 1, GFP_KERNEL); + if(name == NULL) + goto out; + + strcpy(name, data); + + root_inode = iget(sb, 0); + if(root_inode == NULL) + goto out_free; + + err = init_inode(root_inode, NULL); + if(err) + goto out_put; + + HOSTFS_I(root_inode)->host_filename = name; + + err = -ENOMEM; + sb->s_root = d_alloc_root(root_inode); + if(sb->s_root == NULL) + goto out_put; + + err = read_inode(root_inode); + if(err) + goto out_put; + + return(0); + + out_put: + iput(root_inode); + out_free: + kfree(name); + out: + return(err); +} + +static struct super_block *hostfs_read_sb(struct file_system_type *type, + int flags, const char *dev_name, + void *data) +{ + return(get_sb_nodev(type, flags, data, hostfs_fill_sb_common)); +} + +static struct file_system_type hostfs_type = { + .owner = THIS_MODULE, + .name = "hostfs", + .get_sb = hostfs_read_sb, + .kill_sb = kill_anon_super, + .fs_flags = 0, +}; + +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"); + +/* + * Overrides for Emacs so that we follow Linus's tabbing style. + * Emacs will notice this stuff at the end of the file and automatically + * adjust the settings for this buffer only. This must remain at the end + * of the file. + * --------------------------------------------------------------------------- + * Local variables: + * c-file-style: "linux" + * End: + */ |