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![Linus Torvalds](/assets/img/avatar_default.png)
Pull more mount API conversions from Al Viro: "Assorted conversions of options parsing to new API. gfs2 is probably the most serious one here; the rest is trivial stuff. Other things in what used to be #work.mount are going to wait for the next cycle (and preferably go via git trees of the filesystems involved)" * 'work.mount3' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: gfs2: Convert gfs2 to fs_context vfs: Convert spufs to use the new mount API vfs: Convert hypfs to use the new mount API hypfs: Fix error number left in struct pointer member vfs: Convert functionfs to use the new mount API vfs: Convert bpf to use the new mount API
509 lines
12 KiB
C
509 lines
12 KiB
C
// SPDX-License-Identifier: GPL-1.0+
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/*
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* Hypervisor filesystem for Linux on s390.
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*
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* Copyright IBM Corp. 2006, 2008
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* Author(s): Michael Holzheu <holzheu@de.ibm.com>
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*/
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#define KMSG_COMPONENT "hypfs"
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#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
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#include <linux/types.h>
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#include <linux/errno.h>
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#include <linux/fs.h>
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#include <linux/fs_context.h>
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#include <linux/fs_parser.h>
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#include <linux/namei.h>
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#include <linux/vfs.h>
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#include <linux/slab.h>
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#include <linux/pagemap.h>
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#include <linux/time.h>
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#include <linux/sysfs.h>
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#include <linux/init.h>
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#include <linux/kobject.h>
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#include <linux/seq_file.h>
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#include <linux/uio.h>
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#include <asm/ebcdic.h>
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#include "hypfs.h"
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#define HYPFS_MAGIC 0x687970 /* ASCII 'hyp' */
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#define TMP_SIZE 64 /* size of temporary buffers */
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static struct dentry *hypfs_create_update_file(struct dentry *dir);
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struct hypfs_sb_info {
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kuid_t uid; /* uid used for files and dirs */
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kgid_t gid; /* gid used for files and dirs */
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struct dentry *update_file; /* file to trigger update */
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time64_t last_update; /* last update, CLOCK_MONOTONIC time */
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struct mutex lock; /* lock to protect update process */
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};
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static const struct file_operations hypfs_file_ops;
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static struct file_system_type hypfs_type;
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static const struct super_operations hypfs_s_ops;
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/* start of list of all dentries, which have to be deleted on update */
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static struct dentry *hypfs_last_dentry;
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static void hypfs_update_update(struct super_block *sb)
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{
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struct hypfs_sb_info *sb_info = sb->s_fs_info;
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struct inode *inode = d_inode(sb_info->update_file);
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sb_info->last_update = ktime_get_seconds();
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inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
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}
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/* directory tree removal functions */
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static void hypfs_add_dentry(struct dentry *dentry)
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{
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dentry->d_fsdata = hypfs_last_dentry;
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hypfs_last_dentry = dentry;
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}
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static void hypfs_remove(struct dentry *dentry)
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{
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struct dentry *parent;
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parent = dentry->d_parent;
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inode_lock(d_inode(parent));
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if (simple_positive(dentry)) {
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if (d_is_dir(dentry))
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simple_rmdir(d_inode(parent), dentry);
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else
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simple_unlink(d_inode(parent), dentry);
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}
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d_drop(dentry);
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dput(dentry);
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inode_unlock(d_inode(parent));
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}
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static void hypfs_delete_tree(struct dentry *root)
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{
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while (hypfs_last_dentry) {
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struct dentry *next_dentry;
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next_dentry = hypfs_last_dentry->d_fsdata;
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hypfs_remove(hypfs_last_dentry);
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hypfs_last_dentry = next_dentry;
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}
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}
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static struct inode *hypfs_make_inode(struct super_block *sb, umode_t mode)
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{
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struct inode *ret = new_inode(sb);
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if (ret) {
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struct hypfs_sb_info *hypfs_info = sb->s_fs_info;
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ret->i_ino = get_next_ino();
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ret->i_mode = mode;
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ret->i_uid = hypfs_info->uid;
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ret->i_gid = hypfs_info->gid;
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ret->i_atime = ret->i_mtime = ret->i_ctime = current_time(ret);
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if (S_ISDIR(mode))
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set_nlink(ret, 2);
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}
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return ret;
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}
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static void hypfs_evict_inode(struct inode *inode)
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{
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clear_inode(inode);
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kfree(inode->i_private);
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}
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static int hypfs_open(struct inode *inode, struct file *filp)
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{
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char *data = file_inode(filp)->i_private;
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struct hypfs_sb_info *fs_info;
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if (filp->f_mode & FMODE_WRITE) {
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if (!(inode->i_mode & S_IWUGO))
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return -EACCES;
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}
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if (filp->f_mode & FMODE_READ) {
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if (!(inode->i_mode & S_IRUGO))
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return -EACCES;
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}
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fs_info = inode->i_sb->s_fs_info;
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if(data) {
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mutex_lock(&fs_info->lock);
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filp->private_data = kstrdup(data, GFP_KERNEL);
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if (!filp->private_data) {
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mutex_unlock(&fs_info->lock);
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return -ENOMEM;
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}
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mutex_unlock(&fs_info->lock);
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}
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return nonseekable_open(inode, filp);
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}
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static ssize_t hypfs_read_iter(struct kiocb *iocb, struct iov_iter *to)
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{
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struct file *file = iocb->ki_filp;
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char *data = file->private_data;
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size_t available = strlen(data);
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loff_t pos = iocb->ki_pos;
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size_t count;
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if (pos < 0)
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return -EINVAL;
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if (pos >= available || !iov_iter_count(to))
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return 0;
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count = copy_to_iter(data + pos, available - pos, to);
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if (!count)
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return -EFAULT;
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iocb->ki_pos = pos + count;
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file_accessed(file);
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return count;
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}
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static ssize_t hypfs_write_iter(struct kiocb *iocb, struct iov_iter *from)
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{
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int rc;
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struct super_block *sb = file_inode(iocb->ki_filp)->i_sb;
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struct hypfs_sb_info *fs_info = sb->s_fs_info;
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size_t count = iov_iter_count(from);
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/*
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* Currently we only allow one update per second for two reasons:
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* 1. diag 204 is VERY expensive
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* 2. If several processes do updates in parallel and then read the
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* hypfs data, the likelihood of collisions is reduced, if we restrict
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* the minimum update interval. A collision occurs, if during the
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* data gathering of one process another process triggers an update
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* If the first process wants to ensure consistent data, it has
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* to restart data collection in this case.
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*/
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mutex_lock(&fs_info->lock);
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if (fs_info->last_update == ktime_get_seconds()) {
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rc = -EBUSY;
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goto out;
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}
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hypfs_delete_tree(sb->s_root);
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if (MACHINE_IS_VM)
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rc = hypfs_vm_create_files(sb->s_root);
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else
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rc = hypfs_diag_create_files(sb->s_root);
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if (rc) {
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pr_err("Updating the hypfs tree failed\n");
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hypfs_delete_tree(sb->s_root);
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goto out;
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}
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hypfs_update_update(sb);
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rc = count;
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iov_iter_advance(from, count);
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out:
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mutex_unlock(&fs_info->lock);
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return rc;
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}
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static int hypfs_release(struct inode *inode, struct file *filp)
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{
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kfree(filp->private_data);
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return 0;
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}
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enum { Opt_uid, Opt_gid, };
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static const struct fs_parameter_spec hypfs_param_specs[] = {
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fsparam_u32("gid", Opt_gid),
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fsparam_u32("uid", Opt_uid),
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{}
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};
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static const struct fs_parameter_description hypfs_fs_parameters = {
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.name = "hypfs",
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.specs = hypfs_param_specs,
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};
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static int hypfs_parse_param(struct fs_context *fc, struct fs_parameter *param)
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{
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struct hypfs_sb_info *hypfs_info = fc->s_fs_info;
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struct fs_parse_result result;
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kuid_t uid;
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kgid_t gid;
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int opt;
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opt = fs_parse(fc, &hypfs_fs_parameters, param, &result);
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if (opt < 0)
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return opt;
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switch (opt) {
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case Opt_uid:
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uid = make_kuid(current_user_ns(), result.uint_32);
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if (!uid_valid(uid))
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return invalf(fc, "Unknown uid");
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hypfs_info->uid = uid;
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break;
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case Opt_gid:
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gid = make_kgid(current_user_ns(), result.uint_32);
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if (!gid_valid(gid))
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return invalf(fc, "Unknown gid");
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hypfs_info->gid = gid;
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break;
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}
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return 0;
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}
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static int hypfs_show_options(struct seq_file *s, struct dentry *root)
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{
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struct hypfs_sb_info *hypfs_info = root->d_sb->s_fs_info;
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seq_printf(s, ",uid=%u", from_kuid_munged(&init_user_ns, hypfs_info->uid));
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seq_printf(s, ",gid=%u", from_kgid_munged(&init_user_ns, hypfs_info->gid));
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return 0;
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}
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static int hypfs_fill_super(struct super_block *sb, struct fs_context *fc)
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{
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struct hypfs_sb_info *sbi = sb->s_fs_info;
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struct inode *root_inode;
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struct dentry *root_dentry, *update_file;
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int rc;
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sb->s_blocksize = PAGE_SIZE;
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sb->s_blocksize_bits = PAGE_SHIFT;
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sb->s_magic = HYPFS_MAGIC;
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sb->s_op = &hypfs_s_ops;
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root_inode = hypfs_make_inode(sb, S_IFDIR | 0755);
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if (!root_inode)
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return -ENOMEM;
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root_inode->i_op = &simple_dir_inode_operations;
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root_inode->i_fop = &simple_dir_operations;
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sb->s_root = root_dentry = d_make_root(root_inode);
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if (!root_dentry)
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return -ENOMEM;
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if (MACHINE_IS_VM)
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rc = hypfs_vm_create_files(root_dentry);
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else
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rc = hypfs_diag_create_files(root_dentry);
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if (rc)
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return rc;
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update_file = hypfs_create_update_file(root_dentry);
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if (IS_ERR(update_file))
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return PTR_ERR(update_file);
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sbi->update_file = update_file;
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hypfs_update_update(sb);
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pr_info("Hypervisor filesystem mounted\n");
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return 0;
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}
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static int hypfs_get_tree(struct fs_context *fc)
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{
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return get_tree_single(fc, hypfs_fill_super);
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}
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static void hypfs_free_fc(struct fs_context *fc)
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{
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kfree(fc->s_fs_info);
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}
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static const struct fs_context_operations hypfs_context_ops = {
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.free = hypfs_free_fc,
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.parse_param = hypfs_parse_param,
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.get_tree = hypfs_get_tree,
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};
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static int hypfs_init_fs_context(struct fs_context *fc)
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{
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struct hypfs_sb_info *sbi;
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sbi = kzalloc(sizeof(struct hypfs_sb_info), GFP_KERNEL);
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if (!sbi)
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return -ENOMEM;
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mutex_init(&sbi->lock);
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sbi->uid = current_uid();
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sbi->gid = current_gid();
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fc->s_fs_info = sbi;
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fc->ops = &hypfs_context_ops;
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return 0;
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}
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static void hypfs_kill_super(struct super_block *sb)
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{
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struct hypfs_sb_info *sb_info = sb->s_fs_info;
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if (sb->s_root)
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hypfs_delete_tree(sb->s_root);
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if (sb_info && sb_info->update_file)
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hypfs_remove(sb_info->update_file);
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kfree(sb->s_fs_info);
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sb->s_fs_info = NULL;
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kill_litter_super(sb);
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}
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static struct dentry *hypfs_create_file(struct dentry *parent, const char *name,
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char *data, umode_t mode)
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{
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struct dentry *dentry;
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struct inode *inode;
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inode_lock(d_inode(parent));
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dentry = lookup_one_len(name, parent, strlen(name));
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if (IS_ERR(dentry)) {
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dentry = ERR_PTR(-ENOMEM);
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goto fail;
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}
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inode = hypfs_make_inode(parent->d_sb, mode);
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if (!inode) {
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dput(dentry);
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dentry = ERR_PTR(-ENOMEM);
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goto fail;
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}
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if (S_ISREG(mode)) {
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inode->i_fop = &hypfs_file_ops;
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if (data)
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inode->i_size = strlen(data);
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else
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inode->i_size = 0;
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} else if (S_ISDIR(mode)) {
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inode->i_op = &simple_dir_inode_operations;
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inode->i_fop = &simple_dir_operations;
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inc_nlink(d_inode(parent));
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} else
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BUG();
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inode->i_private = data;
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d_instantiate(dentry, inode);
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dget(dentry);
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fail:
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inode_unlock(d_inode(parent));
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return dentry;
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}
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struct dentry *hypfs_mkdir(struct dentry *parent, const char *name)
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{
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struct dentry *dentry;
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dentry = hypfs_create_file(parent, name, NULL, S_IFDIR | DIR_MODE);
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if (IS_ERR(dentry))
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return dentry;
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hypfs_add_dentry(dentry);
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return dentry;
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}
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static struct dentry *hypfs_create_update_file(struct dentry *dir)
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{
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struct dentry *dentry;
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dentry = hypfs_create_file(dir, "update", NULL,
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S_IFREG | UPDATE_FILE_MODE);
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/*
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* We do not put the update file on the 'delete' list with
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* hypfs_add_dentry(), since it should not be removed when the tree
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* is updated.
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*/
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return dentry;
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}
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struct dentry *hypfs_create_u64(struct dentry *dir,
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const char *name, __u64 value)
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{
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char *buffer;
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char tmp[TMP_SIZE];
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struct dentry *dentry;
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snprintf(tmp, TMP_SIZE, "%llu\n", (unsigned long long int)value);
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buffer = kstrdup(tmp, GFP_KERNEL);
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if (!buffer)
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return ERR_PTR(-ENOMEM);
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dentry =
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hypfs_create_file(dir, name, buffer, S_IFREG | REG_FILE_MODE);
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if (IS_ERR(dentry)) {
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kfree(buffer);
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return ERR_PTR(-ENOMEM);
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}
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hypfs_add_dentry(dentry);
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return dentry;
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}
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struct dentry *hypfs_create_str(struct dentry *dir,
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const char *name, char *string)
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{
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char *buffer;
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struct dentry *dentry;
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buffer = kmalloc(strlen(string) + 2, GFP_KERNEL);
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if (!buffer)
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return ERR_PTR(-ENOMEM);
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sprintf(buffer, "%s\n", string);
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dentry =
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hypfs_create_file(dir, name, buffer, S_IFREG | REG_FILE_MODE);
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if (IS_ERR(dentry)) {
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kfree(buffer);
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return ERR_PTR(-ENOMEM);
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}
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hypfs_add_dentry(dentry);
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return dentry;
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}
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static const struct file_operations hypfs_file_ops = {
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.open = hypfs_open,
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.release = hypfs_release,
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.read_iter = hypfs_read_iter,
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.write_iter = hypfs_write_iter,
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.llseek = no_llseek,
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};
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static struct file_system_type hypfs_type = {
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.owner = THIS_MODULE,
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.name = "s390_hypfs",
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.init_fs_context = hypfs_init_fs_context,
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.parameters = &hypfs_fs_parameters,
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.kill_sb = hypfs_kill_super
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};
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static const struct super_operations hypfs_s_ops = {
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.statfs = simple_statfs,
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.evict_inode = hypfs_evict_inode,
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.show_options = hypfs_show_options,
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};
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static int __init hypfs_init(void)
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{
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int rc;
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hypfs_dbfs_init();
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if (hypfs_diag_init()) {
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rc = -ENODATA;
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goto fail_dbfs_exit;
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}
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if (hypfs_vm_init()) {
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rc = -ENODATA;
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goto fail_hypfs_diag_exit;
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}
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hypfs_sprp_init();
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if (hypfs_diag0c_init()) {
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rc = -ENODATA;
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goto fail_hypfs_sprp_exit;
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}
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rc = sysfs_create_mount_point(hypervisor_kobj, "s390");
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if (rc)
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goto fail_hypfs_diag0c_exit;
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rc = register_filesystem(&hypfs_type);
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if (rc)
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goto fail_filesystem;
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return 0;
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fail_filesystem:
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sysfs_remove_mount_point(hypervisor_kobj, "s390");
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fail_hypfs_diag0c_exit:
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hypfs_diag0c_exit();
|
|
fail_hypfs_sprp_exit:
|
|
hypfs_sprp_exit();
|
|
hypfs_vm_exit();
|
|
fail_hypfs_diag_exit:
|
|
hypfs_diag_exit();
|
|
fail_dbfs_exit:
|
|
hypfs_dbfs_exit();
|
|
pr_err("Initialization of hypfs failed with rc=%i\n", rc);
|
|
return rc;
|
|
}
|
|
device_initcall(hypfs_init)
|