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 uid_t uid; /* uid used for files and dirs */
35 gid_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 if (!parent || !parent->d_inode)
77 mutex_lock(&parent->d_inode->i_mutex);
78 if (hypfs_positive(dentry)) {
79 if (S_ISDIR(dentry->d_inode->i_mode))
80 simple_rmdir(parent->d_inode, dentry);
82 simple_unlink(parent->d_inode, dentry);
86 mutex_unlock(&parent->d_inode->i_mutex);
89 static void hypfs_delete_tree(struct dentry *root)
91 while (hypfs_last_dentry) {
92 struct dentry *next_dentry;
93 next_dentry = hypfs_last_dentry->d_fsdata;
94 hypfs_remove(hypfs_last_dentry);
95 hypfs_last_dentry = next_dentry;
99 static struct inode *hypfs_make_inode(struct super_block *sb, umode_t mode)
101 struct inode *ret = new_inode(sb);
104 struct hypfs_sb_info *hypfs_info = sb->s_fs_info;
105 ret->i_ino = get_next_ino();
107 ret->i_uid = hypfs_info->uid;
108 ret->i_gid = hypfs_info->gid;
109 ret->i_atime = ret->i_mtime = ret->i_ctime = CURRENT_TIME;
116 static void hypfs_evict_inode(struct inode *inode)
119 kfree(inode->i_private);
122 static int hypfs_open(struct inode *inode, struct file *filp)
124 char *data = filp->f_path.dentry->d_inode->i_private;
125 struct hypfs_sb_info *fs_info;
127 if (filp->f_mode & FMODE_WRITE) {
128 if (!(inode->i_mode & S_IWUGO))
131 if (filp->f_mode & FMODE_READ) {
132 if (!(inode->i_mode & S_IRUGO))
136 fs_info = inode->i_sb->s_fs_info;
138 mutex_lock(&fs_info->lock);
139 filp->private_data = kstrdup(data, GFP_KERNEL);
140 if (!filp->private_data) {
141 mutex_unlock(&fs_info->lock);
144 mutex_unlock(&fs_info->lock);
146 return nonseekable_open(inode, filp);
149 static ssize_t hypfs_aio_read(struct kiocb *iocb, const struct iovec *iov,
150 unsigned long nr_segs, loff_t offset)
154 struct file *filp = iocb->ki_filp;
156 char __user *buf = iov[0].iov_base;
157 size_t count = iov[0].iov_len;
162 data = filp->private_data;
163 ret = simple_read_from_buffer(buf, count, &offset, data, strlen(data));
172 static ssize_t hypfs_aio_write(struct kiocb *iocb, const struct iovec *iov,
173 unsigned long nr_segs, loff_t offset)
176 struct super_block *sb;
177 struct hypfs_sb_info *fs_info;
178 size_t count = iov_length(iov, nr_segs);
180 sb = iocb->ki_filp->f_path.dentry->d_inode->i_sb;
181 fs_info = sb->s_fs_info;
183 * Currently we only allow one update per second for two reasons:
184 * 1. diag 204 is VERY expensive
185 * 2. If several processes do updates in parallel and then read the
186 * hypfs data, the likelihood of collisions is reduced, if we restrict
187 * the minimum update interval. A collision occurs, if during the
188 * data gathering of one process another process triggers an update
189 * If the first process wants to ensure consistent data, it has
190 * to restart data collection in this case.
192 mutex_lock(&fs_info->lock);
193 if (fs_info->last_update == get_seconds()) {
197 hypfs_delete_tree(sb->s_root);
199 rc = hypfs_vm_create_files(sb, sb->s_root);
201 rc = hypfs_diag_create_files(sb, sb->s_root);
203 pr_err("Updating the hypfs tree failed\n");
204 hypfs_delete_tree(sb->s_root);
207 hypfs_update_update(sb);
210 mutex_unlock(&fs_info->lock);
214 static int hypfs_release(struct inode *inode, struct file *filp)
216 kfree(filp->private_data);
220 enum { opt_uid, opt_gid, opt_err };
222 static const match_table_t hypfs_tokens = {
228 static int hypfs_parse_options(char *options, struct super_block *sb)
231 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 hypfs_info->uid = option;
249 if (match_int(&args[0], &option))
251 hypfs_info->gid = option;
255 pr_err("%s is not a valid mount option\n", str);
262 static int hypfs_show_options(struct seq_file *s, struct dentry *root)
264 struct hypfs_sb_info *hypfs_info = root->d_sb->s_fs_info;
266 seq_printf(s, ",uid=%u", hypfs_info->uid);
267 seq_printf(s, ",gid=%u", hypfs_info->gid);
271 static int hypfs_fill_super(struct super_block *sb, void *data, int silent)
273 struct inode *root_inode;
274 struct dentry *root_dentry;
276 struct hypfs_sb_info *sbi;
278 sbi = kzalloc(sizeof(struct hypfs_sb_info), GFP_KERNEL);
281 mutex_init(&sbi->lock);
282 sbi->uid = current_uid();
283 sbi->gid = current_gid();
285 sb->s_blocksize = PAGE_CACHE_SIZE;
286 sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
287 sb->s_magic = HYPFS_MAGIC;
288 sb->s_op = &hypfs_s_ops;
289 if (hypfs_parse_options(data, sb))
291 root_inode = hypfs_make_inode(sb, S_IFDIR | 0755);
294 root_inode->i_op = &simple_dir_inode_operations;
295 root_inode->i_fop = &simple_dir_operations;
296 sb->s_root = root_dentry = d_make_root(root_inode);
300 rc = hypfs_vm_create_files(sb, root_dentry);
302 rc = hypfs_diag_create_files(sb, root_dentry);
305 sbi->update_file = hypfs_create_update_file(sb, root_dentry);
306 if (IS_ERR(sbi->update_file))
307 return PTR_ERR(sbi->update_file);
308 hypfs_update_update(sb);
309 pr_info("Hypervisor filesystem mounted\n");
313 static struct dentry *hypfs_mount(struct file_system_type *fst, int flags,
314 const char *devname, void *data)
316 return mount_single(fst, flags, data, hypfs_fill_super);
319 static void hypfs_kill_super(struct super_block *sb)
321 struct hypfs_sb_info *sb_info = sb->s_fs_info;
324 hypfs_delete_tree(sb->s_root);
325 if (sb_info->update_file)
326 hypfs_remove(sb_info->update_file);
327 kfree(sb->s_fs_info);
328 sb->s_fs_info = NULL;
329 kill_litter_super(sb);
332 static struct dentry *hypfs_create_file(struct super_block *sb,
333 struct dentry *parent, const char *name,
334 char *data, umode_t mode)
336 struct dentry *dentry;
339 mutex_lock(&parent->d_inode->i_mutex);
340 dentry = lookup_one_len(name, parent, strlen(name));
341 if (IS_ERR(dentry)) {
342 dentry = ERR_PTR(-ENOMEM);
345 inode = hypfs_make_inode(sb, mode);
348 dentry = ERR_PTR(-ENOMEM);
352 inode->i_fop = &hypfs_file_ops;
354 inode->i_size = strlen(data);
357 } else if (S_ISDIR(mode)) {
358 inode->i_op = &simple_dir_inode_operations;
359 inode->i_fop = &simple_dir_operations;
360 inc_nlink(parent->d_inode);
363 inode->i_private = data;
364 d_instantiate(dentry, inode);
367 mutex_unlock(&parent->d_inode->i_mutex);
371 struct dentry *hypfs_mkdir(struct super_block *sb, struct dentry *parent,
374 struct dentry *dentry;
376 dentry = hypfs_create_file(sb, parent, name, NULL, S_IFDIR | DIR_MODE);
379 hypfs_add_dentry(dentry);
383 static struct dentry *hypfs_create_update_file(struct super_block *sb,
386 struct dentry *dentry;
388 dentry = hypfs_create_file(sb, dir, "update", NULL,
389 S_IFREG | UPDATE_FILE_MODE);
391 * We do not put the update file on the 'delete' list with
392 * hypfs_add_dentry(), since it should not be removed when the tree
398 struct dentry *hypfs_create_u64(struct super_block *sb, struct dentry *dir,
399 const char *name, __u64 value)
403 struct dentry *dentry;
405 snprintf(tmp, TMP_SIZE, "%llu\n", (unsigned long long int)value);
406 buffer = kstrdup(tmp, GFP_KERNEL);
408 return ERR_PTR(-ENOMEM);
410 hypfs_create_file(sb, dir, name, buffer, S_IFREG | REG_FILE_MODE);
411 if (IS_ERR(dentry)) {
413 return ERR_PTR(-ENOMEM);
415 hypfs_add_dentry(dentry);
419 struct dentry *hypfs_create_str(struct super_block *sb, struct dentry *dir,
420 const char *name, char *string)
423 struct dentry *dentry;
425 buffer = kmalloc(strlen(string) + 2, GFP_KERNEL);
427 return ERR_PTR(-ENOMEM);
428 sprintf(buffer, "%s\n", string);
430 hypfs_create_file(sb, dir, name, buffer, S_IFREG | REG_FILE_MODE);
431 if (IS_ERR(dentry)) {
433 return ERR_PTR(-ENOMEM);
435 hypfs_add_dentry(dentry);
439 static const struct file_operations hypfs_file_ops = {
441 .release = hypfs_release,
442 .read = do_sync_read,
443 .write = do_sync_write,
444 .aio_read = hypfs_aio_read,
445 .aio_write = hypfs_aio_write,
449 static struct file_system_type hypfs_type = {
450 .owner = THIS_MODULE,
451 .name = "s390_hypfs",
452 .mount = hypfs_mount,
453 .kill_sb = hypfs_kill_super
456 static const struct super_operations hypfs_s_ops = {
457 .statfs = simple_statfs,
458 .evict_inode = hypfs_evict_inode,
459 .show_options = hypfs_show_options,
462 static struct kobject *s390_kobj;
464 static int __init hypfs_init(void)
468 rc = hypfs_dbfs_init();
471 if (hypfs_diag_init()) {
475 if (hypfs_vm_init()) {
477 goto fail_hypfs_diag_exit;
479 s390_kobj = kobject_create_and_add("s390", hypervisor_kobj);
482 goto fail_hypfs_vm_exit;
484 rc = register_filesystem(&hypfs_type);
486 goto fail_filesystem;
490 kobject_put(s390_kobj);
493 fail_hypfs_diag_exit:
497 pr_err("Initialization of hypfs failed with rc=%i\n", rc);
501 static void __exit hypfs_exit(void)
506 unregister_filesystem(&hypfs_type);
507 kobject_put(s390_kobj);
510 module_init(hypfs_init)
511 module_exit(hypfs_exit)
513 MODULE_LICENSE("GPL");
514 MODULE_AUTHOR("Michael Holzheu <holzheu@de.ibm.com>");
515 MODULE_DESCRIPTION("s390 Hypervisor Filesystem");