v4.19.13 snapshot.
diff --git a/fs/hostfs/hostfs_kern.c b/fs/hostfs/hostfs_kern.c
new file mode 100644
index 0000000..444c7b1
--- /dev/null
+++ b/fs/hostfs/hostfs_kern.c
@@ -0,0 +1,1006 @@
+/*
+ * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
+ * Licensed under the GPL
+ *
+ * Ported the filesystem routines to 2.5.
+ * 2003-02-10 Petr Baudis <pasky@ucw.cz>
+ */
+
+#include <linux/fs.h>
+#include <linux/magic.h>
+#include <linux/module.h>
+#include <linux/mm.h>
+#include <linux/pagemap.h>
+#include <linux/statfs.h>
+#include <linux/slab.h>
+#include <linux/seq_file.h>
+#include <linux/mount.h>
+#include <linux/namei.h>
+#include "hostfs.h"
+#include <init.h>
+#include <kern.h>
+
+struct hostfs_inode_info {
+ int fd;
+ fmode_t mode;
+ struct inode vfs_inode;
+ struct mutex open_mutex;
+};
+
+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_inode(file))
+
+/* Changed in hostfs_args before the kernel starts running */
+static char *root_ino = "";
+static int append = 0;
+
+static const struct inode_operations hostfs_iops;
+static const struct inode_operations hostfs_dir_iops;
+static const struct inode_operations hostfs_link_iops;
+
+#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, char *name)
+{
+ char *p = dentry_path_raw(dentry, name, PATH_MAX);
+ char *root;
+ size_t len;
+
+ root = dentry->d_sb->s_fs_info;
+ len = strlen(root);
+ if (IS_ERR(p)) {
+ __putname(name);
+ return NULL;
+ }
+
+ /*
+ * This function relies on the fact that dentry_path_raw() will place
+ * the path name at the end of the provided buffer.
+ */
+ BUG_ON(p + strlen(p) + 1 != name + PATH_MAX);
+
+ strlcpy(name, root, PATH_MAX);
+ if (len > p - name) {
+ __putname(name);
+ return NULL;
+ }
+
+ if (p > name + len)
+ strcpy(name + len, p);
+
+ return name;
+}
+
+static char *dentry_name(struct dentry *dentry)
+{
+ char *name = __getname();
+ if (!name)
+ return NULL;
+
+ return __dentry_name(dentry, name);
+}
+
+static char *inode_name(struct inode *ino)
+{
+ struct dentry *dentry;
+ char *name;
+
+ dentry = d_find_alias(ino);
+ if (!dentry)
+ return NULL;
+
+ name = dentry_name(dentry);
+
+ dput(dentry);
+
+ return name;
+}
+
+static char *follow_link(char *link)
+{
+ int len, n;
+ char *name, *resolved, *end;
+
+ name = __getname();
+ if (!name) {
+ n = -ENOMEM;
+ goto out_free;
+ }
+
+ n = hostfs_do_readlink(link, name, PATH_MAX);
+ if (n < 0)
+ goto out_free;
+ else if (n == PATH_MAX) {
+ n = -E2BIG;
+ 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);
+ __putname(name);
+ kfree(link);
+ return resolved;
+
+ out_free:
+ __putname(name);
+ return ERR_PTR(n);
+}
+
+static struct inode *hostfs_iget(struct super_block *sb)
+{
+ struct inode *inode = new_inode(sb);
+ if (!inode)
+ return ERR_PTR(-ENOMEM);
+ return inode;
+}
+
+static int hostfs_statfs(struct dentry *dentry, 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(dentry->d_sb->s_fs_info,
+ &sf->f_bsize, &f_blocks, &f_bfree, &f_bavail, &f_files,
+ &f_ffree, &sf->f_fsid, sizeof(sf->f_fsid),
+ &sf->f_namelen);
+ 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_ACCOUNT);
+ if (hi == NULL)
+ return NULL;
+ hi->fd = -1;
+ hi->mode = 0;
+ inode_init_once(&hi->vfs_inode);
+ mutex_init(&hi->open_mutex);
+ return &hi->vfs_inode;
+}
+
+static void hostfs_evict_inode(struct inode *inode)
+{
+ truncate_inode_pages_final(&inode->i_data);
+ clear_inode(inode);
+ if (HOSTFS_I(inode)->fd != -1) {
+ close_file(&HOSTFS_I(inode)->fd);
+ HOSTFS_I(inode)->fd = -1;
+ }
+}
+
+static void hostfs_i_callback(struct rcu_head *head)
+{
+ struct inode *inode = container_of(head, struct inode, i_rcu);
+ kfree(HOSTFS_I(inode));
+}
+
+static void hostfs_destroy_inode(struct inode *inode)
+{
+ call_rcu(&inode->i_rcu, hostfs_i_callback);
+}
+
+static int hostfs_show_options(struct seq_file *seq, struct dentry *root)
+{
+ const char *root_path = root->d_sb->s_fs_info;
+ size_t offset = strlen(root_ino) + 1;
+
+ if (strlen(root_path) > offset)
+ seq_show_option(seq, root_path + offset, NULL);
+
+ if (append)
+ seq_puts(seq, ",append");
+
+ return 0;
+}
+
+static const struct super_operations hostfs_sbops = {
+ .alloc_inode = hostfs_alloc_inode,
+ .destroy_inode = hostfs_destroy_inode,
+ .evict_inode = hostfs_evict_inode,
+ .statfs = hostfs_statfs,
+ .show_options = hostfs_show_options,
+};
+
+static int hostfs_readdir(struct file *file, struct dir_context *ctx)
+{
+ void *dir;
+ char *name;
+ unsigned long long next, ino;
+ int error, len;
+ unsigned int type;
+
+ name = dentry_name(file->f_path.dentry);
+ if (name == NULL)
+ return -ENOMEM;
+ dir = open_dir(name, &error);
+ __putname(name);
+ if (dir == NULL)
+ return -error;
+ next = ctx->pos;
+ seek_dir(dir, next);
+ while ((name = read_dir(dir, &next, &ino, &len, &type)) != NULL) {
+ if (!dir_emit(ctx, name, len, ino, type))
+ break;
+ ctx->pos = next;
+ }
+ close_dir(dir);
+ return 0;
+}
+
+static int hostfs_open(struct inode *ino, struct file *file)
+{
+ char *name;
+ fmode_t mode;
+ int err;
+ int r, w, fd;
+
+ mode = file->f_mode & (FMODE_READ | FMODE_WRITE);
+ if ((mode & HOSTFS_I(ino)->mode) == mode)
+ return 0;
+
+ mode |= HOSTFS_I(ino)->mode;
+
+retry:
+ r = w = 0;
+
+ if (mode & FMODE_READ)
+ r = 1;
+ if (mode & FMODE_WRITE)
+ r = w = 1;
+
+ name = dentry_name(file->f_path.dentry);
+ if (name == NULL)
+ return -ENOMEM;
+
+ fd = open_file(name, r, w, append);
+ __putname(name);
+ if (fd < 0)
+ return fd;
+
+ mutex_lock(&HOSTFS_I(ino)->open_mutex);
+ /* somebody else had handled it first? */
+ if ((mode & HOSTFS_I(ino)->mode) == mode) {
+ mutex_unlock(&HOSTFS_I(ino)->open_mutex);
+ close_file(&fd);
+ return 0;
+ }
+ if ((mode | HOSTFS_I(ino)->mode) != mode) {
+ mode |= HOSTFS_I(ino)->mode;
+ mutex_unlock(&HOSTFS_I(ino)->open_mutex);
+ close_file(&fd);
+ goto retry;
+ }
+ if (HOSTFS_I(ino)->fd == -1) {
+ HOSTFS_I(ino)->fd = fd;
+ } else {
+ err = replace_file(fd, HOSTFS_I(ino)->fd);
+ close_file(&fd);
+ if (err < 0) {
+ mutex_unlock(&HOSTFS_I(ino)->open_mutex);
+ return err;
+ }
+ }
+ HOSTFS_I(ino)->mode = mode;
+ mutex_unlock(&HOSTFS_I(ino)->open_mutex);
+
+ return 0;
+}
+
+static int hostfs_file_release(struct inode *inode, struct file *file)
+{
+ filemap_write_and_wait(inode->i_mapping);
+
+ return 0;
+}
+
+static int hostfs_fsync(struct file *file, loff_t start, loff_t end,
+ int datasync)
+{
+ struct inode *inode = file->f_mapping->host;
+ int ret;
+
+ ret = file_write_and_wait_range(file, start, end);
+ if (ret)
+ return ret;
+
+ inode_lock(inode);
+ ret = fsync_file(HOSTFS_I(inode)->fd, datasync);
+ inode_unlock(inode);
+
+ return ret;
+}
+
+static const struct file_operations hostfs_file_fops = {
+ .llseek = generic_file_llseek,
+ .splice_read = generic_file_splice_read,
+ .read_iter = generic_file_read_iter,
+ .write_iter = generic_file_write_iter,
+ .mmap = generic_file_mmap,
+ .open = hostfs_open,
+ .release = hostfs_file_release,
+ .fsync = hostfs_fsync,
+};
+
+static const struct file_operations hostfs_dir_fops = {
+ .llseek = generic_file_llseek,
+ .iterate_shared = hostfs_readdir,
+ .read = generic_read_dir,
+ .open = hostfs_open,
+ .fsync = hostfs_fsync,
+};
+
+static int hostfs_writepage(struct page *page, struct writeback_control *wbc)
+{
+ struct address_space *mapping = page->mapping;
+ struct inode *inode = mapping->host;
+ char *buffer;
+ loff_t base = page_offset(page);
+ int count = PAGE_SIZE;
+ int end_index = inode->i_size >> PAGE_SHIFT;
+ int err;
+
+ if (page->index >= end_index)
+ count = inode->i_size & (PAGE_SIZE-1);
+
+ buffer = kmap(page);
+
+ 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;
+}
+
+static int hostfs_readpage(struct file *file, struct page *page)
+{
+ char *buffer;
+ loff_t start = page_offset(page);
+ int bytes_read, ret = 0;
+
+ buffer = kmap(page);
+ bytes_read = read_file(FILE_HOSTFS_I(file)->fd, &start, buffer,
+ PAGE_SIZE);
+ if (bytes_read < 0) {
+ ClearPageUptodate(page);
+ SetPageError(page);
+ ret = bytes_read;
+ goto out;
+ }
+
+ memset(buffer + bytes_read, 0, PAGE_SIZE - bytes_read);
+
+ ClearPageError(page);
+ SetPageUptodate(page);
+
+ out:
+ flush_dcache_page(page);
+ kunmap(page);
+ unlock_page(page);
+ return ret;
+}
+
+static int hostfs_write_begin(struct file *file, struct address_space *mapping,
+ loff_t pos, unsigned len, unsigned flags,
+ struct page **pagep, void **fsdata)
+{
+ pgoff_t index = pos >> PAGE_SHIFT;
+
+ *pagep = grab_cache_page_write_begin(mapping, index, flags);
+ if (!*pagep)
+ return -ENOMEM;
+ return 0;
+}
+
+static int hostfs_write_end(struct file *file, struct address_space *mapping,
+ loff_t pos, unsigned len, unsigned copied,
+ struct page *page, void *fsdata)
+{
+ struct inode *inode = mapping->host;
+ void *buffer;
+ unsigned from = pos & (PAGE_SIZE - 1);
+ int err;
+
+ buffer = kmap(page);
+ err = write_file(FILE_HOSTFS_I(file)->fd, &pos, buffer + from, copied);
+ kunmap(page);
+
+ if (!PageUptodate(page) && err == PAGE_SIZE)
+ SetPageUptodate(page);
+
+ /*
+ * If err > 0, write_file has added err to pos, so we are comparing
+ * i_size against the last byte written.
+ */
+ if (err > 0 && (pos > inode->i_size))
+ inode->i_size = pos;
+ unlock_page(page);
+ put_page(page);
+
+ return err;
+}
+
+static const struct address_space_operations hostfs_aops = {
+ .writepage = hostfs_writepage,
+ .readpage = hostfs_readpage,
+ .set_page_dirty = __set_page_dirty_nobuffers,
+ .write_begin = hostfs_write_begin,
+ .write_end = hostfs_write_end,
+};
+
+static int read_name(struct inode *ino, char *name)
+{
+ dev_t rdev;
+ struct hostfs_stat st;
+ int err = stat_file(name, &st, -1);
+ if (err)
+ return err;
+
+ /* Reencode maj and min with the kernel encoding.*/
+ rdev = MKDEV(st.maj, st.min);
+
+ switch (st.mode & S_IFMT) {
+ case S_IFLNK:
+ ino->i_op = &hostfs_link_iops;
+ break;
+ case S_IFDIR:
+ ino->i_op = &hostfs_dir_iops;
+ ino->i_fop = &hostfs_dir_fops;
+ break;
+ case S_IFCHR:
+ case S_IFBLK:
+ case S_IFIFO:
+ case S_IFSOCK:
+ init_special_inode(ino, st.mode & S_IFMT, rdev);
+ ino->i_op = &hostfs_iops;
+ break;
+ case S_IFREG:
+ ino->i_op = &hostfs_iops;
+ ino->i_fop = &hostfs_file_fops;
+ ino->i_mapping->a_ops = &hostfs_aops;
+ break;
+ default:
+ 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");