2 * arch/s390/hypfs/inode.c
3 * Hypervisor filesystem for Linux on s390.
5 * Copyright (C) IBM Corp. 2006
6 * Author(s): Michael Holzheu <holzheu@de.ibm.com>
9 #include <linux/types.h>
10 #include <linux/errno.h>
12 #include <linux/namei.h>
13 #include <linux/vfs.h>
14 #include <linux/pagemap.h>
15 #include <linux/gfp.h>
16 #include <linux/time.h>
17 #include <linux/parser.h>
18 #include <linux/sysfs.h>
19 #include <linux/module.h>
20 #include <asm/ebcdic.h>
22 #include "hypfs_diag.h"
24 #define HYPFS_MAGIC 0x687970 /* ASCII 'hyp' */
25 #define TMP_SIZE 64 /* size of temporary buffers */
27 static struct dentry *hypfs_create_update_file(struct super_block *sb,
30 struct hypfs_sb_info {
31 uid_t uid; /* uid used for files and dirs */
32 gid_t gid; /* gid used for files and dirs */
33 struct dentry *update_file; /* file to trigger update */
34 time_t last_update; /* last update time in secs since 1970 */
35 struct mutex lock; /* lock to protect update process */
38 static struct file_operations hypfs_file_ops;
39 static struct file_system_type hypfs_type;
40 static struct super_operations hypfs_s_ops;
42 /* start of list of all dentries, which have to be deleted on update */
43 static struct dentry *hypfs_last_dentry;
45 static void hypfs_update_update(struct super_block *sb)
47 struct hypfs_sb_info *sb_info = sb->s_fs_info;
48 struct inode *inode = sb_info->update_file->d_inode;
50 sb_info->last_update = get_seconds();
51 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
54 /* directory tree removal functions */
56 static void hypfs_add_dentry(struct dentry *dentry)
58 dentry->d_fsdata = hypfs_last_dentry;
59 hypfs_last_dentry = dentry;
62 static void hypfs_remove(struct dentry *dentry)
64 struct dentry *parent;
66 parent = dentry->d_parent;
67 if (S_ISDIR(dentry->d_inode->i_mode))
68 simple_rmdir(parent->d_inode, dentry);
70 simple_unlink(parent->d_inode, dentry);
75 static void hypfs_delete_tree(struct dentry *root)
77 while (hypfs_last_dentry) {
78 struct dentry *next_dentry;
79 next_dentry = hypfs_last_dentry->d_fsdata;
80 hypfs_remove(hypfs_last_dentry);
81 hypfs_last_dentry = next_dentry;
85 static struct inode *hypfs_make_inode(struct super_block *sb, int mode)
87 struct inode *ret = new_inode(sb);
90 struct hypfs_sb_info *hypfs_info = sb->s_fs_info;
92 ret->i_uid = hypfs_info->uid;
93 ret->i_gid = hypfs_info->gid;
95 ret->i_atime = ret->i_mtime = ret->i_ctime = CURRENT_TIME;
104 static void hypfs_drop_inode(struct inode *inode)
106 kfree(inode->i_private);
107 generic_delete_inode(inode);
110 static int hypfs_open(struct inode *inode, struct file *filp)
112 char *data = filp->f_dentry->d_inode->i_private;
113 struct hypfs_sb_info *fs_info;
115 if (filp->f_mode & FMODE_WRITE) {
116 if (!(inode->i_mode & S_IWUGO))
119 if (filp->f_mode & FMODE_READ) {
120 if (!(inode->i_mode & S_IRUGO))
124 fs_info = inode->i_sb->s_fs_info;
126 mutex_lock(&fs_info->lock);
127 filp->private_data = kstrdup(data, GFP_KERNEL);
128 if (!filp->private_data) {
129 mutex_unlock(&fs_info->lock);
132 mutex_unlock(&fs_info->lock);
137 static ssize_t hypfs_aio_read(struct kiocb *iocb, __user char *buf,
138 size_t count, loff_t offset)
142 struct file *filp = iocb->ki_filp;
144 data = filp->private_data;
150 if (count > len - offset)
151 count = len - offset;
152 if (copy_to_user(buf, data + offset, count)) {
156 iocb->ki_pos += count;
161 static ssize_t hypfs_aio_write(struct kiocb *iocb, const char __user *buf,
162 size_t count, loff_t pos)
165 struct super_block *sb;
166 struct hypfs_sb_info *fs_info;
168 sb = iocb->ki_filp->f_dentry->d_inode->i_sb;
169 fs_info = sb->s_fs_info;
171 * Currently we only allow one update per second for two reasons:
172 * 1. diag 204 is VERY expensive
173 * 2. If several processes do updates in parallel and then read the
174 * hypfs data, the likelihood of collisions is reduced, if we restrict
175 * the minimum update interval. A collision occurs, if during the
176 * data gathering of one process another process triggers an update
177 * If the first process wants to ensure consistent data, it has
178 * to restart data collection in this case.
180 mutex_lock(&fs_info->lock);
181 if (fs_info->last_update == get_seconds()) {
185 hypfs_delete_tree(sb->s_root);
186 rc = hypfs_diag_create_files(sb, sb->s_root);
188 printk(KERN_ERR "hypfs: Update failed\n");
189 hypfs_delete_tree(sb->s_root);
192 hypfs_update_update(sb);
195 mutex_unlock(&fs_info->lock);
199 static int hypfs_release(struct inode *inode, struct file *filp)
201 kfree(filp->private_data);
205 enum { opt_uid, opt_gid, opt_err };
207 static match_table_t hypfs_tokens = {
213 static int hypfs_parse_options(char *options, struct super_block *sb)
216 substring_t args[MAX_OPT_ARGS];
220 while ((str = strsep(&options, ",")) != NULL) {
222 struct hypfs_sb_info *hypfs_info = sb->s_fs_info;
226 token = match_token(str, hypfs_tokens, args);
229 if (match_int(&args[0], &option))
231 hypfs_info->uid = option;
234 if (match_int(&args[0], &option))
236 hypfs_info->gid = option;
240 printk(KERN_ERR "hypfs: Unrecognized mount option "
241 "\"%s\" or missing value\n", str);
248 static int hypfs_fill_super(struct super_block *sb, void *data, int silent)
250 struct inode *root_inode;
251 struct dentry *root_dentry;
253 struct hypfs_sb_info *sbi;
255 sbi = kzalloc(sizeof(struct hypfs_sb_info), GFP_KERNEL);
258 mutex_init(&sbi->lock);
259 sbi->uid = current->uid;
260 sbi->gid = current->gid;
262 sb->s_blocksize = PAGE_CACHE_SIZE;
263 sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
264 sb->s_magic = HYPFS_MAGIC;
265 sb->s_op = &hypfs_s_ops;
266 if (hypfs_parse_options(data, sb)) {
270 root_inode = hypfs_make_inode(sb, S_IFDIR | 0755);
275 root_inode->i_op = &simple_dir_inode_operations;
276 root_inode->i_fop = &simple_dir_operations;
277 root_dentry = d_alloc_root(root_inode);
283 rc = hypfs_diag_create_files(sb, root_dentry);
286 sbi->update_file = hypfs_create_update_file(sb, root_dentry);
287 if (IS_ERR(sbi->update_file)) {
288 rc = PTR_ERR(sbi->update_file);
291 hypfs_update_update(sb);
292 sb->s_root = root_dentry;
296 hypfs_delete_tree(root_dentry);
297 d_genocide(root_dentry);
304 static int hypfs_get_super(struct file_system_type *fst, int flags,
305 const char *devname, void *data, struct vfsmount *mnt)
307 return get_sb_single(fst, flags, data, hypfs_fill_super, mnt);
310 static void hypfs_kill_super(struct super_block *sb)
312 struct hypfs_sb_info *sb_info = sb->s_fs_info;
315 hypfs_delete_tree(sb->s_root);
316 hypfs_remove(sb_info->update_file);
317 kfree(sb->s_fs_info);
318 sb->s_fs_info = NULL;
320 kill_litter_super(sb);
323 static struct dentry *hypfs_create_file(struct super_block *sb,
324 struct dentry *parent, const char *name,
325 char *data, mode_t mode)
327 struct dentry *dentry;
332 qname.len = strlen(name);
333 qname.hash = full_name_hash(name, qname.len);
334 dentry = lookup_one_len(name, parent, strlen(name));
336 return ERR_PTR(-ENOMEM);
337 inode = hypfs_make_inode(sb, mode);
340 return ERR_PTR(-ENOMEM);
342 if (mode & S_IFREG) {
343 inode->i_fop = &hypfs_file_ops;
345 inode->i_size = strlen(data);
348 } else if (mode & S_IFDIR) {
349 inode->i_op = &simple_dir_inode_operations;
350 inode->i_fop = &simple_dir_operations;
351 parent->d_inode->i_nlink++;
354 inode->i_private = data;
355 d_instantiate(dentry, inode);
360 struct dentry *hypfs_mkdir(struct super_block *sb, struct dentry *parent,
363 struct dentry *dentry;
365 dentry = hypfs_create_file(sb, parent, name, NULL, S_IFDIR | DIR_MODE);
368 hypfs_add_dentry(dentry);
369 parent->d_inode->i_nlink++;
373 static struct dentry *hypfs_create_update_file(struct super_block *sb,
376 struct dentry *dentry;
378 dentry = hypfs_create_file(sb, dir, "update", NULL,
379 S_IFREG | UPDATE_FILE_MODE);
381 * We do not put the update file on the 'delete' list with
382 * hypfs_add_dentry(), since it should not be removed when the tree
388 struct dentry *hypfs_create_u64(struct super_block *sb, struct dentry *dir,
389 const char *name, __u64 value)
393 struct dentry *dentry;
395 snprintf(tmp, TMP_SIZE, "%lld\n", (unsigned long long int)value);
396 buffer = kstrdup(tmp, GFP_KERNEL);
398 return ERR_PTR(-ENOMEM);
400 hypfs_create_file(sb, dir, name, buffer, S_IFREG | REG_FILE_MODE);
401 if (IS_ERR(dentry)) {
403 return ERR_PTR(-ENOMEM);
405 hypfs_add_dentry(dentry);
409 struct dentry *hypfs_create_str(struct super_block *sb, struct dentry *dir,
410 const char *name, char *string)
413 struct dentry *dentry;
415 buffer = kmalloc(strlen(string) + 2, GFP_KERNEL);
417 return ERR_PTR(-ENOMEM);
418 sprintf(buffer, "%s\n", string);
420 hypfs_create_file(sb, dir, name, buffer, S_IFREG | REG_FILE_MODE);
421 if (IS_ERR(dentry)) {
423 return ERR_PTR(-ENOMEM);
425 hypfs_add_dentry(dentry);
429 static struct file_operations hypfs_file_ops = {
431 .release = hypfs_release,
432 .read = do_sync_read,
433 .write = do_sync_write,
434 .aio_read = hypfs_aio_read,
435 .aio_write = hypfs_aio_write,
438 static struct file_system_type hypfs_type = {
439 .owner = THIS_MODULE,
440 .name = "s390_hypfs",
441 .get_sb = hypfs_get_super,
442 .kill_sb = hypfs_kill_super
445 static struct super_operations hypfs_s_ops = {
446 .statfs = simple_statfs,
447 .drop_inode = hypfs_drop_inode,
450 static decl_subsys(s390, NULL, NULL);
452 static int __init hypfs_init(void)
458 if (hypfs_diag_init()) {
462 kset_set_kset_s(&s390_subsys, hypervisor_subsys);
463 rc = subsystem_register(&s390_subsys);
466 rc = register_filesystem(&hypfs_type);
468 goto fail_filesystem;
472 subsystem_unregister(&s390_subsys);
476 printk(KERN_ERR "hypfs: Initialization failed with rc = %i.\n", rc);
480 static void __exit hypfs_exit(void)
483 unregister_filesystem(&hypfs_type);
484 subsystem_unregister(&s390_subsys);
487 module_init(hypfs_init)
488 module_exit(hypfs_exit)
490 MODULE_LICENSE("GPL");
491 MODULE_AUTHOR("Michael Holzheu <holzheu@de.ibm.com>");
492 MODULE_DESCRIPTION("s390 Hypervisor Filesystem");