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504 lines
12 KiB
504 lines
12 KiB
// 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 <[email protected]> |
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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_fs_parameters[] = { |
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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 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(); |
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fail_hypfs_sprp_exit: |
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hypfs_sprp_exit(); |
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hypfs_vm_exit(); |
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fail_hypfs_diag_exit: |
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hypfs_diag_exit(); |
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fail_dbfs_exit: |
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hypfs_dbfs_exit(); |
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pr_err("Initialization of hypfs failed with rc=%i\n", rc); |
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return rc; |
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} |
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device_initcall(hypfs_init)
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