2 * arch/s390/hypfs/inode.c
3 * Hypervisor filesystem for Linux on s390.
5 * Copyright IBM Corp. 2006, 2008
6 * Author(s): Michael Holzheu <holzheu@de.ibm.com>
9 #define KMSG_COMPONENT "hypfs"
10 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
12 #include <linux/types.h>
13 #include <linux/errno.h>
15 #include <linux/namei.h>
16 #include <linux/vfs.h>
17 #include <linux/pagemap.h>
18 #include <linux/gfp.h>
19 #include <linux/time.h>
20 #include <linux/parser.h>
21 #include <linux/sysfs.h>
22 #include <linux/module.h>
23 #include <linux/seq_file.h>
24 #include <linux/mount.h>
25 #include <asm/ebcdic.h>
28 #define HYPFS_MAGIC 0x687970 /* ASCII 'hyp' */
29 #define TMP_SIZE 64 /* size of temporary buffers */
31 static struct dentry *hypfs_create_update_file(struct super_block *sb,
34 struct hypfs_sb_info {
35 uid_t uid; /* uid used for files and dirs */
36 gid_t gid; /* gid used for files and dirs */
37 struct dentry *update_file; /* file to trigger update */
38 time_t last_update; /* last update time in secs since 1970 */
39 struct mutex lock; /* lock to protect update process */
42 static const struct file_operations hypfs_file_ops;
43 static struct file_system_type hypfs_type;
44 static struct super_operations hypfs_s_ops;
46 /* start of list of all dentries, which have to be deleted on update */
47 static struct dentry *hypfs_last_dentry;
49 static void hypfs_update_update(struct super_block *sb)
51 struct hypfs_sb_info *sb_info = sb->s_fs_info;
52 struct inode *inode = sb_info->update_file->d_inode;
54 sb_info->last_update = get_seconds();
55 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
58 /* directory tree removal functions */
60 static void hypfs_add_dentry(struct dentry *dentry)
62 dentry->d_fsdata = hypfs_last_dentry;
63 hypfs_last_dentry = dentry;
66 static inline int hypfs_positive(struct dentry *dentry)
68 return dentry->d_inode && !d_unhashed(dentry);
71 static void hypfs_remove(struct dentry *dentry)
73 struct dentry *parent;
75 parent = dentry->d_parent;
76 if (!parent || !parent->d_inode)
78 mutex_lock(&parent->d_inode->i_mutex);
79 if (hypfs_positive(dentry)) {
80 if (S_ISDIR(dentry->d_inode->i_mode))
81 simple_rmdir(parent->d_inode, dentry);
83 simple_unlink(parent->d_inode, dentry);
87 mutex_unlock(&parent->d_inode->i_mutex);
90 static void hypfs_delete_tree(struct dentry *root)
92 while (hypfs_last_dentry) {
93 struct dentry *next_dentry;
94 next_dentry = hypfs_last_dentry->d_fsdata;
95 hypfs_remove(hypfs_last_dentry);
96 hypfs_last_dentry = next_dentry;
100 static struct inode *hypfs_make_inode(struct super_block *sb, int mode)
102 struct inode *ret = new_inode(sb);
105 struct hypfs_sb_info *hypfs_info = sb->s_fs_info;
107 ret->i_uid = hypfs_info->uid;
108 ret->i_gid = hypfs_info->gid;
110 ret->i_atime = ret->i_mtime = ret->i_ctime = CURRENT_TIME;
119 static void hypfs_drop_inode(struct inode *inode)
121 kfree(inode->i_private);
122 generic_delete_inode(inode);
125 static int hypfs_open(struct inode *inode, struct file *filp)
127 char *data = filp->f_path.dentry->d_inode->i_private;
128 struct hypfs_sb_info *fs_info;
130 if (filp->f_mode & FMODE_WRITE) {
131 if (!(inode->i_mode & S_IWUGO))
134 if (filp->f_mode & FMODE_READ) {
135 if (!(inode->i_mode & S_IRUGO))
139 fs_info = inode->i_sb->s_fs_info;
141 mutex_lock(&fs_info->lock);
142 filp->private_data = kstrdup(data, GFP_KERNEL);
143 if (!filp->private_data) {
144 mutex_unlock(&fs_info->lock);
147 mutex_unlock(&fs_info->lock);
152 static ssize_t hypfs_aio_read(struct kiocb *iocb, const struct iovec *iov,
153 unsigned long nr_segs, loff_t offset)
157 struct file *filp = iocb->ki_filp;
159 char __user *buf = iov[0].iov_base;
160 size_t count = iov[0].iov_len;
165 data = filp->private_data;
166 ret = simple_read_from_buffer(buf, count, &offset, data, strlen(data));
175 static ssize_t hypfs_aio_write(struct kiocb *iocb, const struct iovec *iov,
176 unsigned long nr_segs, loff_t offset)
179 struct super_block *sb;
180 struct hypfs_sb_info *fs_info;
181 size_t count = iov_length(iov, nr_segs);
183 sb = iocb->ki_filp->f_path.dentry->d_inode->i_sb;
184 fs_info = sb->s_fs_info;
186 * Currently we only allow one update per second for two reasons:
187 * 1. diag 204 is VERY expensive
188 * 2. If several processes do updates in parallel and then read the
189 * hypfs data, the likelihood of collisions is reduced, if we restrict
190 * the minimum update interval. A collision occurs, if during the
191 * data gathering of one process another process triggers an update
192 * If the first process wants to ensure consistent data, it has
193 * to restart data collection in this case.
195 mutex_lock(&fs_info->lock);
196 if (fs_info->last_update == get_seconds()) {
200 hypfs_delete_tree(sb->s_root);
202 rc = hypfs_vm_create_files(sb, sb->s_root);
204 rc = hypfs_diag_create_files(sb, sb->s_root);
206 pr_err("Updating the hypfs tree failed\n");
207 hypfs_delete_tree(sb->s_root);
210 hypfs_update_update(sb);
213 mutex_unlock(&fs_info->lock);
217 static int hypfs_release(struct inode *inode, struct file *filp)
219 kfree(filp->private_data);
223 enum { opt_uid, opt_gid, opt_err };
225 static const match_table_t hypfs_tokens = {
231 static int hypfs_parse_options(char *options, struct super_block *sb)
234 substring_t args[MAX_OPT_ARGS];
238 while ((str = strsep(&options, ",")) != NULL) {
240 struct hypfs_sb_info *hypfs_info = sb->s_fs_info;
244 token = match_token(str, hypfs_tokens, args);
247 if (match_int(&args[0], &option))
249 hypfs_info->uid = option;
252 if (match_int(&args[0], &option))
254 hypfs_info->gid = option;
258 pr_err("%s is not a valid mount option\n", str);
265 static int hypfs_show_options(struct seq_file *s, struct vfsmount *mnt)
267 struct hypfs_sb_info *hypfs_info = mnt->mnt_sb->s_fs_info;
269 seq_printf(s, ",uid=%u", hypfs_info->uid);
270 seq_printf(s, ",gid=%u", hypfs_info->gid);
274 static int hypfs_fill_super(struct super_block *sb, void *data, int silent)
276 struct inode *root_inode;
277 struct dentry *root_dentry;
279 struct hypfs_sb_info *sbi;
281 sbi = kzalloc(sizeof(struct hypfs_sb_info), GFP_KERNEL);
284 mutex_init(&sbi->lock);
285 sbi->uid = current_uid();
286 sbi->gid = current_gid();
288 sb->s_blocksize = PAGE_CACHE_SIZE;
289 sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
290 sb->s_magic = HYPFS_MAGIC;
291 sb->s_op = &hypfs_s_ops;
292 if (hypfs_parse_options(data, sb)) {
296 root_inode = hypfs_make_inode(sb, S_IFDIR | 0755);
301 root_inode->i_op = &simple_dir_inode_operations;
302 root_inode->i_fop = &simple_dir_operations;
303 root_dentry = d_alloc_root(root_inode);
310 rc = hypfs_vm_create_files(sb, root_dentry);
312 rc = hypfs_diag_create_files(sb, root_dentry);
315 sbi->update_file = hypfs_create_update_file(sb, root_dentry);
316 if (IS_ERR(sbi->update_file)) {
317 rc = PTR_ERR(sbi->update_file);
320 hypfs_update_update(sb);
321 sb->s_root = root_dentry;
322 pr_info("Hypervisor filesystem mounted\n");
326 hypfs_delete_tree(root_dentry);
327 d_genocide(root_dentry);
334 static int hypfs_get_super(struct file_system_type *fst, int flags,
335 const char *devname, void *data, struct vfsmount *mnt)
337 return get_sb_single(fst, flags, data, hypfs_fill_super, mnt);
340 static void hypfs_kill_super(struct super_block *sb)
342 struct hypfs_sb_info *sb_info = sb->s_fs_info;
345 hypfs_delete_tree(sb->s_root);
346 hypfs_remove(sb_info->update_file);
347 kfree(sb->s_fs_info);
348 sb->s_fs_info = NULL;
350 kill_litter_super(sb);
353 static struct dentry *hypfs_create_file(struct super_block *sb,
354 struct dentry *parent, const char *name,
355 char *data, mode_t mode)
357 struct dentry *dentry;
362 qname.len = strlen(name);
363 qname.hash = full_name_hash(name, qname.len);
364 mutex_lock(&parent->d_inode->i_mutex);
365 dentry = lookup_one_len(name, parent, strlen(name));
366 if (IS_ERR(dentry)) {
367 dentry = ERR_PTR(-ENOMEM);
370 inode = hypfs_make_inode(sb, mode);
373 dentry = ERR_PTR(-ENOMEM);
376 if (mode & S_IFREG) {
377 inode->i_fop = &hypfs_file_ops;
379 inode->i_size = strlen(data);
382 } else if (mode & S_IFDIR) {
383 inode->i_op = &simple_dir_inode_operations;
384 inode->i_fop = &simple_dir_operations;
385 parent->d_inode->i_nlink++;
388 inode->i_private = data;
389 d_instantiate(dentry, inode);
392 mutex_unlock(&parent->d_inode->i_mutex);
396 struct dentry *hypfs_mkdir(struct super_block *sb, struct dentry *parent,
399 struct dentry *dentry;
401 dentry = hypfs_create_file(sb, parent, name, NULL, S_IFDIR | DIR_MODE);
404 hypfs_add_dentry(dentry);
408 static struct dentry *hypfs_create_update_file(struct super_block *sb,
411 struct dentry *dentry;
413 dentry = hypfs_create_file(sb, dir, "update", NULL,
414 S_IFREG | UPDATE_FILE_MODE);
416 * We do not put the update file on the 'delete' list with
417 * hypfs_add_dentry(), since it should not be removed when the tree
423 struct dentry *hypfs_create_u64(struct super_block *sb, struct dentry *dir,
424 const char *name, __u64 value)
428 struct dentry *dentry;
430 snprintf(tmp, TMP_SIZE, "%lld\n", (unsigned long long int)value);
431 buffer = kstrdup(tmp, GFP_KERNEL);
433 return ERR_PTR(-ENOMEM);
435 hypfs_create_file(sb, dir, name, buffer, S_IFREG | REG_FILE_MODE);
436 if (IS_ERR(dentry)) {
438 return ERR_PTR(-ENOMEM);
440 hypfs_add_dentry(dentry);
444 struct dentry *hypfs_create_str(struct super_block *sb, struct dentry *dir,
445 const char *name, char *string)
448 struct dentry *dentry;
450 buffer = kmalloc(strlen(string) + 2, GFP_KERNEL);
452 return ERR_PTR(-ENOMEM);
453 sprintf(buffer, "%s\n", string);
455 hypfs_create_file(sb, dir, name, buffer, S_IFREG | REG_FILE_MODE);
456 if (IS_ERR(dentry)) {
458 return ERR_PTR(-ENOMEM);
460 hypfs_add_dentry(dentry);
464 static const struct file_operations hypfs_file_ops = {
466 .release = hypfs_release,
467 .read = do_sync_read,
468 .write = do_sync_write,
469 .aio_read = hypfs_aio_read,
470 .aio_write = hypfs_aio_write,
473 static struct file_system_type hypfs_type = {
474 .owner = THIS_MODULE,
475 .name = "s390_hypfs",
476 .get_sb = hypfs_get_super,
477 .kill_sb = hypfs_kill_super
480 static struct super_operations hypfs_s_ops = {
481 .statfs = simple_statfs,
482 .drop_inode = hypfs_drop_inode,
483 .show_options = hypfs_show_options,
486 static struct kobject *s390_kobj;
488 static int __init hypfs_init(void)
494 /* no diag 2fc, just exit */
497 if (hypfs_diag_init()) {
502 s390_kobj = kobject_create_and_add("s390", hypervisor_kobj);
507 rc = register_filesystem(&hypfs_type);
509 goto fail_filesystem;
513 kobject_put(s390_kobj);
518 pr_err("Initialization of hypfs failed with rc=%i\n", rc);
522 static void __exit hypfs_exit(void)
526 unregister_filesystem(&hypfs_type);
527 kobject_put(s390_kobj);
530 module_init(hypfs_init)
531 module_exit(hypfs_exit)
533 MODULE_LICENSE("GPL");
534 MODULE_AUTHOR("Michael Holzheu <holzheu@de.ibm.com>");
535 MODULE_DESCRIPTION("s390 Hypervisor Filesystem");