2 * Hypervisor filesystem for Linux on s390.
4 * Copyright IBM Corp. 2006, 2008
5 * Author(s): Michael Holzheu <holzheu@de.ibm.com>
8 #define KMSG_COMPONENT "hypfs"
9 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
11 #include <linux/types.h>
12 #include <linux/errno.h>
14 #include <linux/namei.h>
15 #include <linux/vfs.h>
16 #include <linux/slab.h>
17 #include <linux/pagemap.h>
18 #include <linux/time.h>
19 #include <linux/parser.h>
20 #include <linux/sysfs.h>
21 #include <linux/module.h>
22 #include <linux/seq_file.h>
23 #include <linux/mount.h>
24 #include <asm/ebcdic.h>
27 #define HYPFS_MAGIC 0x687970 /* ASCII 'hyp' */
28 #define TMP_SIZE 64 /* size of temporary buffers */
30 static struct dentry *hypfs_create_update_file(struct super_block *sb,
33 struct hypfs_sb_info {
34 kuid_t uid; /* uid used for files and dirs */
35 kgid_t gid; /* gid used for files and dirs */
36 struct dentry *update_file; /* file to trigger update */
37 time_t last_update; /* last update time in secs since 1970 */
38 struct mutex lock; /* lock to protect update process */
41 static const struct file_operations hypfs_file_ops;
42 static struct file_system_type hypfs_type;
43 static const struct super_operations hypfs_s_ops;
45 /* start of list of all dentries, which have to be deleted on update */
46 static struct dentry *hypfs_last_dentry;
48 static void hypfs_update_update(struct super_block *sb)
50 struct hypfs_sb_info *sb_info = sb->s_fs_info;
51 struct inode *inode = sb_info->update_file->d_inode;
53 sb_info->last_update = get_seconds();
54 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
57 /* directory tree removal functions */
59 static void hypfs_add_dentry(struct dentry *dentry)
61 dentry->d_fsdata = hypfs_last_dentry;
62 hypfs_last_dentry = dentry;
65 static inline int hypfs_positive(struct dentry *dentry)
67 return dentry->d_inode && !d_unhashed(dentry);
70 static void hypfs_remove(struct dentry *dentry)
72 struct dentry *parent;
74 parent = dentry->d_parent;
75 mutex_lock(&parent->d_inode->i_mutex);
76 if (hypfs_positive(dentry)) {
77 if (S_ISDIR(dentry->d_inode->i_mode))
78 simple_rmdir(parent->d_inode, dentry);
80 simple_unlink(parent->d_inode, dentry);
84 mutex_unlock(&parent->d_inode->i_mutex);
87 static void hypfs_delete_tree(struct dentry *root)
89 while (hypfs_last_dentry) {
90 struct dentry *next_dentry;
91 next_dentry = hypfs_last_dentry->d_fsdata;
92 hypfs_remove(hypfs_last_dentry);
93 hypfs_last_dentry = next_dentry;
97 static struct inode *hypfs_make_inode(struct super_block *sb, umode_t mode)
99 struct inode *ret = new_inode(sb);
102 struct hypfs_sb_info *hypfs_info = sb->s_fs_info;
103 ret->i_ino = get_next_ino();
105 ret->i_uid = hypfs_info->uid;
106 ret->i_gid = hypfs_info->gid;
107 ret->i_atime = ret->i_mtime = ret->i_ctime = CURRENT_TIME;
114 static void hypfs_evict_inode(struct inode *inode)
117 kfree(inode->i_private);
120 static int hypfs_open(struct inode *inode, struct file *filp)
122 char *data = filp->f_path.dentry->d_inode->i_private;
123 struct hypfs_sb_info *fs_info;
125 if (filp->f_mode & FMODE_WRITE) {
126 if (!(inode->i_mode & S_IWUGO))
129 if (filp->f_mode & FMODE_READ) {
130 if (!(inode->i_mode & S_IRUGO))
134 fs_info = inode->i_sb->s_fs_info;
136 mutex_lock(&fs_info->lock);
137 filp->private_data = kstrdup(data, GFP_KERNEL);
138 if (!filp->private_data) {
139 mutex_unlock(&fs_info->lock);
142 mutex_unlock(&fs_info->lock);
144 return nonseekable_open(inode, filp);
147 static ssize_t hypfs_aio_read(struct kiocb *iocb, const struct iovec *iov,
148 unsigned long nr_segs, loff_t offset)
152 struct file *filp = iocb->ki_filp;
154 char __user *buf = iov[0].iov_base;
155 size_t count = iov[0].iov_len;
160 data = filp->private_data;
161 ret = simple_read_from_buffer(buf, count, &offset, data, strlen(data));
170 static ssize_t hypfs_aio_write(struct kiocb *iocb, const struct iovec *iov,
171 unsigned long nr_segs, loff_t offset)
174 struct super_block *sb;
175 struct hypfs_sb_info *fs_info;
176 size_t count = iov_length(iov, nr_segs);
178 sb = iocb->ki_filp->f_path.dentry->d_inode->i_sb;
179 fs_info = sb->s_fs_info;
181 * Currently we only allow one update per second for two reasons:
182 * 1. diag 204 is VERY expensive
183 * 2. If several processes do updates in parallel and then read the
184 * hypfs data, the likelihood of collisions is reduced, if we restrict
185 * the minimum update interval. A collision occurs, if during the
186 * data gathering of one process another process triggers an update
187 * If the first process wants to ensure consistent data, it has
188 * to restart data collection in this case.
190 mutex_lock(&fs_info->lock);
191 if (fs_info->last_update == get_seconds()) {
195 hypfs_delete_tree(sb->s_root);
197 rc = hypfs_vm_create_files(sb, sb->s_root);
199 rc = hypfs_diag_create_files(sb, sb->s_root);
201 pr_err("Updating the hypfs tree failed\n");
202 hypfs_delete_tree(sb->s_root);
205 hypfs_update_update(sb);
208 mutex_unlock(&fs_info->lock);
212 static int hypfs_release(struct inode *inode, struct file *filp)
214 kfree(filp->private_data);
218 enum { opt_uid, opt_gid, opt_err };
220 static const match_table_t hypfs_tokens = {
226 static int hypfs_parse_options(char *options, struct super_block *sb)
229 substring_t args[MAX_OPT_ARGS];
235 while ((str = strsep(&options, ",")) != NULL) {
237 struct hypfs_sb_info *hypfs_info = sb->s_fs_info;
241 token = match_token(str, hypfs_tokens, args);
244 if (match_int(&args[0], &option))
246 uid = make_kuid(current_user_ns(), option);
249 hypfs_info->uid = uid;
252 if (match_int(&args[0], &option))
254 gid = make_kgid(current_user_ns(), option);
257 hypfs_info->gid = gid;
261 pr_err("%s is not a valid mount option\n", str);
268 static int hypfs_show_options(struct seq_file *s, struct dentry *root)
270 struct hypfs_sb_info *hypfs_info = root->d_sb->s_fs_info;
272 seq_printf(s, ",uid=%u", from_kuid_munged(&init_user_ns, hypfs_info->uid));
273 seq_printf(s, ",gid=%u", from_kgid_munged(&init_user_ns, hypfs_info->gid));
277 static int hypfs_fill_super(struct super_block *sb, void *data, int silent)
279 struct inode *root_inode;
280 struct dentry *root_dentry;
282 struct hypfs_sb_info *sbi;
284 sbi = kzalloc(sizeof(struct hypfs_sb_info), GFP_KERNEL);
287 mutex_init(&sbi->lock);
288 sbi->uid = current_uid();
289 sbi->gid = current_gid();
291 sb->s_blocksize = PAGE_CACHE_SIZE;
292 sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
293 sb->s_magic = HYPFS_MAGIC;
294 sb->s_op = &hypfs_s_ops;
295 if (hypfs_parse_options(data, sb))
297 root_inode = hypfs_make_inode(sb, S_IFDIR | 0755);
300 root_inode->i_op = &simple_dir_inode_operations;
301 root_inode->i_fop = &simple_dir_operations;
302 sb->s_root = root_dentry = d_make_root(root_inode);
306 rc = hypfs_vm_create_files(sb, root_dentry);
308 rc = hypfs_diag_create_files(sb, root_dentry);
311 sbi->update_file = hypfs_create_update_file(sb, root_dentry);
312 if (IS_ERR(sbi->update_file))
313 return PTR_ERR(sbi->update_file);
314 hypfs_update_update(sb);
315 pr_info("Hypervisor filesystem mounted\n");
319 static struct dentry *hypfs_mount(struct file_system_type *fst, int flags,
320 const char *devname, void *data)
322 return mount_single(fst, flags, data, hypfs_fill_super);
325 static void hypfs_kill_super(struct super_block *sb)
327 struct hypfs_sb_info *sb_info = sb->s_fs_info;
330 hypfs_delete_tree(sb->s_root);
331 if (sb_info->update_file)
332 hypfs_remove(sb_info->update_file);
333 kfree(sb->s_fs_info);
334 sb->s_fs_info = NULL;
335 kill_litter_super(sb);
338 static struct dentry *hypfs_create_file(struct super_block *sb,
339 struct dentry *parent, const char *name,
340 char *data, umode_t mode)
342 struct dentry *dentry;
345 mutex_lock(&parent->d_inode->i_mutex);
346 dentry = lookup_one_len(name, parent, strlen(name));
347 if (IS_ERR(dentry)) {
348 dentry = ERR_PTR(-ENOMEM);
351 inode = hypfs_make_inode(sb, mode);
354 dentry = ERR_PTR(-ENOMEM);
358 inode->i_fop = &hypfs_file_ops;
360 inode->i_size = strlen(data);
363 } else if (S_ISDIR(mode)) {
364 inode->i_op = &simple_dir_inode_operations;
365 inode->i_fop = &simple_dir_operations;
366 inc_nlink(parent->d_inode);
369 inode->i_private = data;
370 d_instantiate(dentry, inode);
373 mutex_unlock(&parent->d_inode->i_mutex);
377 struct dentry *hypfs_mkdir(struct super_block *sb, struct dentry *parent,
380 struct dentry *dentry;
382 dentry = hypfs_create_file(sb, parent, name, NULL, S_IFDIR | DIR_MODE);
385 hypfs_add_dentry(dentry);
389 static struct dentry *hypfs_create_update_file(struct super_block *sb,
392 struct dentry *dentry;
394 dentry = hypfs_create_file(sb, dir, "update", NULL,
395 S_IFREG | UPDATE_FILE_MODE);
397 * We do not put the update file on the 'delete' list with
398 * hypfs_add_dentry(), since it should not be removed when the tree
404 struct dentry *hypfs_create_u64(struct super_block *sb, struct dentry *dir,
405 const char *name, __u64 value)
409 struct dentry *dentry;
411 snprintf(tmp, TMP_SIZE, "%llu\n", (unsigned long long int)value);
412 buffer = kstrdup(tmp, GFP_KERNEL);
414 return ERR_PTR(-ENOMEM);
416 hypfs_create_file(sb, dir, name, buffer, S_IFREG | REG_FILE_MODE);
417 if (IS_ERR(dentry)) {
419 return ERR_PTR(-ENOMEM);
421 hypfs_add_dentry(dentry);
425 struct dentry *hypfs_create_str(struct super_block *sb, struct dentry *dir,
426 const char *name, char *string)
429 struct dentry *dentry;
431 buffer = kmalloc(strlen(string) + 2, GFP_KERNEL);
433 return ERR_PTR(-ENOMEM);
434 sprintf(buffer, "%s\n", string);
436 hypfs_create_file(sb, dir, name, buffer, S_IFREG | REG_FILE_MODE);
437 if (IS_ERR(dentry)) {
439 return ERR_PTR(-ENOMEM);
441 hypfs_add_dentry(dentry);
445 static const struct file_operations hypfs_file_ops = {
447 .release = hypfs_release,
448 .read = do_sync_read,
449 .write = do_sync_write,
450 .aio_read = hypfs_aio_read,
451 .aio_write = hypfs_aio_write,
455 static struct file_system_type hypfs_type = {
456 .owner = THIS_MODULE,
457 .name = "s390_hypfs",
458 .mount = hypfs_mount,
459 .kill_sb = hypfs_kill_super
462 static const struct super_operations hypfs_s_ops = {
463 .statfs = simple_statfs,
464 .evict_inode = hypfs_evict_inode,
465 .show_options = hypfs_show_options,
468 static struct kobject *s390_kobj;
470 static int __init hypfs_init(void)
474 rc = hypfs_dbfs_init();
477 if (hypfs_diag_init()) {
481 if (hypfs_vm_init()) {
483 goto fail_hypfs_diag_exit;
485 s390_kobj = kobject_create_and_add("s390", hypervisor_kobj);
488 goto fail_hypfs_vm_exit;
490 rc = register_filesystem(&hypfs_type);
492 goto fail_filesystem;
496 kobject_put(s390_kobj);
499 fail_hypfs_diag_exit:
503 pr_err("Initialization of hypfs failed with rc=%i\n", rc);
507 static void __exit hypfs_exit(void)
512 unregister_filesystem(&hypfs_type);
513 kobject_put(s390_kobj);
516 module_init(hypfs_init)
517 module_exit(hypfs_exit)
519 MODULE_LICENSE("GPL");
520 MODULE_AUTHOR("Michael Holzheu <holzheu@de.ibm.com>");
521 MODULE_DESCRIPTION("s390 Hypervisor Filesystem");