arch/s390/hypfs/inode.c

   1 /*
   2  *  arch/s390/hypfs/inode.c
   3  *    Hypervisor filesystem for Linux on s390.
   4  *
   5  *    Copyright IBM Corp. 2006, 2008
   6  *    Author(s): Michael Holzheu <holzheu@de.ibm.com>
   7  */
   8
   9 #define KMSG_COMPONENT "hypfs"
  10 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
  11
  12 #include <linux/types.h>
  13 #include <linux/errno.h>
  14 #include <linux/fs.h>
  15 #include <linux/namei.h>
  16 #include <linux/vfs.h>
  17 #include <linux/slab.h>
  18 #include <linux/pagemap.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>
  26 #include "hypfs.h"
  27
  28 #define HYPFS_MAGIC 0x687970    /* ASCII 'hyp' */
  29 #define TMP_SIZE 64             /* size of temporary buffers */
  30
  31 static struct dentry *hypfs_create_update_file(struct super_block *sb,
  32                                                struct dentry *dir);
  33
  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 */
  40 };
  41
  42 static const struct file_operations hypfs_file_ops;
  43 static struct file_system_type hypfs_type;
  44 static const struct super_operations hypfs_s_ops;
  45
  46 /* start of list of all dentries, which have to be deleted on update */
  47 static struct dentry *hypfs_last_dentry;
  48
  49 static void hypfs_update_update(struct super_block *sb)
  50 {
  51         struct hypfs_sb_info *sb_info = sb->s_fs_info;
  52         struct inode *inode = sb_info->update_file->d_inode;
  53
  54         sb_info->last_update = get_seconds();
  55         inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
  56 }
  57
  58 /* directory tree removal functions */
  59
  60 static void hypfs_add_dentry(struct dentry *dentry)
  61 {
  62         dentry->d_fsdata = hypfs_last_dentry;
  63         hypfs_last_dentry = dentry;
  64 }
  65
  66 static inline int hypfs_positive(struct dentry *dentry)
  67 {
  68         return dentry->d_inode && !d_unhashed(dentry);
  69 }
  70
  71 static void hypfs_remove(struct dentry *dentry)
  72 {
  73         struct dentry *parent;
  74
  75         parent = dentry->d_parent;
  76         if (!parent || !parent->d_inode)
  77                 return;
  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);
  82                 else
  83                         simple_unlink(parent->d_inode, dentry);
  84         }
  85         d_delete(dentry);
  86         dput(dentry);
  87         mutex_unlock(&parent->d_inode->i_mutex);
  88 }
  89
  90 static void hypfs_delete_tree(struct dentry *root)
  91 {
  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;
  97         }
  98 }
  99
 100 static struct inode *hypfs_make_inode(struct super_block *sb, umode_t mode)
 101 {
 102         struct inode *ret = new_inode(sb);
 103
 104         if (ret) {
 105                 struct hypfs_sb_info *hypfs_info = sb->s_fs_info;
 106                 ret->i_ino = get_next_ino();
 107                 ret->i_mode = mode;
 108                 ret->i_uid = hypfs_info->uid;
 109                 ret->i_gid = hypfs_info->gid;
 110                 ret->i_atime = ret->i_mtime = ret->i_ctime = CURRENT_TIME;
 111                 if (S_ISDIR(mode))
 112                         set_nlink(ret, 2);
 113         }
 114         return ret;
 115 }
 116
 117 static void hypfs_evict_inode(struct inode *inode)
 118 {
 119         clear_inode(inode);
 120         kfree(inode->i_private);
 121 }
 122
 123 static int hypfs_open(struct inode *inode, struct file *filp)
 124 {
 125         char *data = filp->f_path.dentry->d_inode->i_private;
 126         struct hypfs_sb_info *fs_info;
 127
 128         if (filp->f_mode & FMODE_WRITE) {
 129                 if (!(inode->i_mode & S_IWUGO))
 130                         return -EACCES;
 131         }
 132         if (filp->f_mode & FMODE_READ) {
 133                 if (!(inode->i_mode & S_IRUGO))
 134                         return -EACCES;
 135         }
 136
 137         fs_info = inode->i_sb->s_fs_info;
 138         if(data) {
 139                 mutex_lock(&fs_info->lock);
 140                 filp->private_data = kstrdup(data, GFP_KERNEL);
 141                 if (!filp->private_data) {
 142                         mutex_unlock(&fs_info->lock);
 143                         return -ENOMEM;
 144                 }
 145                 mutex_unlock(&fs_info->lock);
 146         }
 147         return nonseekable_open(inode, filp);
 148 }
 149
 150 static ssize_t hypfs_aio_read(struct kiocb *iocb, const struct iovec *iov,
 151                               unsigned long nr_segs, loff_t offset)
 152 {
 153         char *data;
 154         ssize_t ret;
 155         struct file *filp = iocb->ki_filp;
 156         /* XXX: temporary */
 157         char __user *buf = iov[0].iov_base;
 158         size_t count = iov[0].iov_len;
 159
 160         if (nr_segs != 1)
 161                 return -EINVAL;
 162
 163         data = filp->private_data;
 164         ret = simple_read_from_buffer(buf, count, &offset, data, strlen(data));
 165         if (ret <= 0)
 166                 return ret;
 167
 168         iocb->ki_pos += ret;
 169         file_accessed(filp);
 170
 171         return ret;
 172 }
 173 static ssize_t hypfs_aio_write(struct kiocb *iocb, const struct iovec *iov,
 174                               unsigned long nr_segs, loff_t offset)
 175 {
 176         int rc;
 177         struct super_block *sb;
 178         struct hypfs_sb_info *fs_info;
 179         size_t count = iov_length(iov, nr_segs);
 180
 181         sb = iocb->ki_filp->f_path.dentry->d_inode->i_sb;
 182         fs_info = sb->s_fs_info;
 183         /*
 184          * Currently we only allow one update per second for two reasons:
 185          * 1. diag 204 is VERY expensive
 186          * 2. If several processes do updates in parallel and then read the
 187          *    hypfs data, the likelihood of collisions is reduced, if we restrict
 188          *    the minimum update interval. A collision occurs, if during the
 189          *    data gathering of one process another process triggers an update
 190          *    If the first process wants to ensure consistent data, it has
 191          *    to restart data collection in this case.
 192          */
 193         mutex_lock(&fs_info->lock);
 194         if (fs_info->last_update == get_seconds()) {
 195                 rc = -EBUSY;
 196                 goto out;
 197         }
 198         hypfs_delete_tree(sb->s_root);
 199         if (MACHINE_IS_VM)
 200                 rc = hypfs_vm_create_files(sb, sb->s_root);
 201         else
 202                 rc = hypfs_diag_create_files(sb, sb->s_root);
 203         if (rc) {
 204                 pr_err("Updating the hypfs tree failed\n");
 205                 hypfs_delete_tree(sb->s_root);
 206                 goto out;
 207         }
 208         hypfs_update_update(sb);
 209         rc = count;
 210 out:
 211         mutex_unlock(&fs_info->lock);
 212         return rc;
 213 }
 214
 215 static int hypfs_release(struct inode *inode, struct file *filp)
 216 {
 217         kfree(filp->private_data);
 218         return 0;
 219 }
 220
 221 enum { opt_uid, opt_gid, opt_err };
 222
 223 static const match_table_t hypfs_tokens = {
 224         {opt_uid, "uid=%u"},
 225         {opt_gid, "gid=%u"},
 226         {opt_err, NULL}
 227 };
 228
 229 static int hypfs_parse_options(char *options, struct super_block *sb)
 230 {
 231         char *str;
 232         substring_t args[MAX_OPT_ARGS];
 233
 234         if (!options)
 235                 return 0;
 236         while ((str = strsep(&options, ",")) != NULL) {
 237                 int token, option;
 238                 struct hypfs_sb_info *hypfs_info = sb->s_fs_info;
 239
 240                 if (!*str)
 241                         continue;
 242                 token = match_token(str, hypfs_tokens, args);
 243                 switch (token) {
 244                 case opt_uid:
 245                         if (match_int(&args[0], &option))
 246                                 return -EINVAL;
 247                         hypfs_info->uid = option;
 248                         break;
 249                 case opt_gid:
 250                         if (match_int(&args[0], &option))
 251                                 return -EINVAL;
 252                         hypfs_info->gid = option;
 253                         break;
 254                 case opt_err:
 255                 default:
 256                         pr_err("%s is not a valid mount option\n", str);
 257                         return -EINVAL;
 258                 }
 259         }
 260         return 0;
 261 }
 262
 263 static int hypfs_show_options(struct seq_file *s, struct dentry *root)
 264 {
 265         struct hypfs_sb_info *hypfs_info = root->d_sb->s_fs_info;
 266
 267         seq_printf(s, ",uid=%u", hypfs_info->uid);
 268         seq_printf(s, ",gid=%u", hypfs_info->gid);
 269         return 0;
 270 }
 271
 272 static int hypfs_fill_super(struct super_block *sb, void *data, int silent)
 273 {
 274         struct inode *root_inode;
 275         struct dentry *root_dentry;
 276         int rc = 0;
 277         struct hypfs_sb_info *sbi;
 278
 279         sbi = kzalloc(sizeof(struct hypfs_sb_info), GFP_KERNEL);
 280         if (!sbi)
 281                 return -ENOMEM;
 282         mutex_init(&sbi->lock);
 283         sbi->uid = current_uid();
 284         sbi->gid = current_gid();
 285         sb->s_fs_info = sbi;
 286         sb->s_blocksize = PAGE_CACHE_SIZE;
 287         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
 288         sb->s_magic = HYPFS_MAGIC;
 289         sb->s_op = &hypfs_s_ops;
 290         if (hypfs_parse_options(data, sb))
 291                 return -EINVAL;
 292         root_inode = hypfs_make_inode(sb, S_IFDIR | 0755);
 293         if (!root_inode)
 294                 return -ENOMEM;
 295         root_inode->i_op = &simple_dir_inode_operations;
 296         root_inode->i_fop = &simple_dir_operations;
 297         sb->s_root = root_dentry = d_make_root(root_inode);
 298         if (!root_dentry)
 299                 return -ENOMEM;
 300         if (MACHINE_IS_VM)
 301                 rc = hypfs_vm_create_files(sb, root_dentry);
 302         else
 303                 rc = hypfs_diag_create_files(sb, root_dentry);
 304         if (rc)
 305                 return rc;
 306         sbi->update_file = hypfs_create_update_file(sb, root_dentry);
 307         if (IS_ERR(sbi->update_file))
 308                 return PTR_ERR(sbi->update_file);
 309         hypfs_update_update(sb);
 310         pr_info("Hypervisor filesystem mounted\n");
 311         return 0;
 312 }
 313
 314 static struct dentry *hypfs_mount(struct file_system_type *fst, int flags,
 315                         const char *devname, void *data)
 316 {
 317         return mount_single(fst, flags, data, hypfs_fill_super);
 318 }
 319
 320 static void hypfs_kill_super(struct super_block *sb)
 321 {
 322         struct hypfs_sb_info *sb_info = sb->s_fs_info;
 323
 324         if (sb->s_root)
 325                 hypfs_delete_tree(sb->s_root);
 326         if (sb_info->update_file)
 327                 hypfs_remove(sb_info->update_file);
 328         kfree(sb->s_fs_info);
 329         sb->s_fs_info = NULL;
 330         kill_litter_super(sb);
 331 }
 332
 333 static struct dentry *hypfs_create_file(struct super_block *sb,
 334                                         struct dentry *parent, const char *name,
 335                                         char *data, umode_t mode)
 336 {
 337         struct dentry *dentry;
 338         struct inode *inode;
 339
 340         mutex_lock(&parent->d_inode->i_mutex);
 341         dentry = lookup_one_len(name, parent, strlen(name));
 342         if (IS_ERR(dentry)) {
 343                 dentry = ERR_PTR(-ENOMEM);
 344                 goto fail;
 345         }
 346         inode = hypfs_make_inode(sb, mode);
 347         if (!inode) {
 348                 dput(dentry);
 349                 dentry = ERR_PTR(-ENOMEM);
 350                 goto fail;
 351         }
 352         if (S_ISREG(mode)) {
 353                 inode->i_fop = &hypfs_file_ops;
 354                 if (data)
 355                         inode->i_size = strlen(data);
 356                 else
 357                         inode->i_size = 0;
 358         } else if (S_ISDIR(mode)) {
 359                 inode->i_op = &simple_dir_inode_operations;
 360                 inode->i_fop = &simple_dir_operations;
 361                 inc_nlink(parent->d_inode);
 362         } else
 363                 BUG();
 364         inode->i_private = data;
 365         d_instantiate(dentry, inode);
 366         dget(dentry);
 367 fail:
 368         mutex_unlock(&parent->d_inode->i_mutex);
 369         return dentry;
 370 }
 371
 372 struct dentry *hypfs_mkdir(struct super_block *sb, struct dentry *parent,
 373                            const char *name)
 374 {
 375         struct dentry *dentry;
 376
 377         dentry = hypfs_create_file(sb, parent, name, NULL, S_IFDIR | DIR_MODE);
 378         if (IS_ERR(dentry))
 379                 return dentry;
 380         hypfs_add_dentry(dentry);
 381         return dentry;
 382 }
 383
 384 static struct dentry *hypfs_create_update_file(struct super_block *sb,
 385                                                struct dentry *dir)
 386 {
 387         struct dentry *dentry;
 388
 389         dentry = hypfs_create_file(sb, dir, "update", NULL,
 390                                    S_IFREG | UPDATE_FILE_MODE);
 391         /*
 392          * We do not put the update file on the 'delete' list with
 393          * hypfs_add_dentry(), since it should not be removed when the tree
 394          * is updated.
 395          */
 396         return dentry;
 397 }
 398
 399 struct dentry *hypfs_create_u64(struct super_block *sb, struct dentry *dir,
 400                                 const char *name, __u64 value)
 401 {
 402         char *buffer;
 403         char tmp[TMP_SIZE];
 404         struct dentry *dentry;
 405
 406         snprintf(tmp, TMP_SIZE, "%llu\n", (unsigned long long int)value);
 407         buffer = kstrdup(tmp, GFP_KERNEL);
 408         if (!buffer)
 409                 return ERR_PTR(-ENOMEM);
 410         dentry =
 411             hypfs_create_file(sb, dir, name, buffer, S_IFREG | REG_FILE_MODE);
 412         if (IS_ERR(dentry)) {
 413                 kfree(buffer);
 414                 return ERR_PTR(-ENOMEM);
 415         }
 416         hypfs_add_dentry(dentry);
 417         return dentry;
 418 }
 419
 420 struct dentry *hypfs_create_str(struct super_block *sb, struct dentry *dir,
 421                                 const char *name, char *string)
 422 {
 423         char *buffer;
 424         struct dentry *dentry;
 425
 426         buffer = kmalloc(strlen(string) + 2, GFP_KERNEL);
 427         if (!buffer)
 428                 return ERR_PTR(-ENOMEM);
 429         sprintf(buffer, "%s\n", string);
 430         dentry =
 431             hypfs_create_file(sb, dir, name, buffer, S_IFREG | REG_FILE_MODE);
 432         if (IS_ERR(dentry)) {
 433                 kfree(buffer);
 434                 return ERR_PTR(-ENOMEM);
 435         }
 436         hypfs_add_dentry(dentry);
 437         return dentry;
 438 }
 439
 440 static const struct file_operations hypfs_file_ops = {
 441         .open           = hypfs_open,
 442         .release        = hypfs_release,
 443         .read           = do_sync_read,
 444         .write          = do_sync_write,
 445         .aio_read       = hypfs_aio_read,
 446         .aio_write      = hypfs_aio_write,
 447         .llseek         = no_llseek,
 448 };
 449
 450 static struct file_system_type hypfs_type = {
 451         .owner          = THIS_MODULE,
 452         .name           = "s390_hypfs",
 453         .mount          = hypfs_mount,
 454         .kill_sb        = hypfs_kill_super
 455 };
 456
 457 static const struct super_operations hypfs_s_ops = {
 458         .statfs         = simple_statfs,
 459         .evict_inode    = hypfs_evict_inode,
 460         .show_options   = hypfs_show_options,
 461 };
 462
 463 static struct kobject *s390_kobj;
 464
 465 static int __init hypfs_init(void)
 466 {
 467         int rc;
 468
 469         rc = hypfs_dbfs_init();
 470         if (rc)
 471                 return rc;
 472         if (hypfs_diag_init()) {
 473                 rc = -ENODATA;
 474                 goto fail_dbfs_exit;
 475         }
 476         if (hypfs_vm_init()) {
 477                 rc = -ENODATA;
 478                 goto fail_hypfs_diag_exit;
 479         }
 480         s390_kobj = kobject_create_and_add("s390", hypervisor_kobj);
 481         if (!s390_kobj) {
 482                 rc = -ENOMEM;
 483                 goto fail_hypfs_vm_exit;
 484         }
 485         rc = register_filesystem(&hypfs_type);
 486         if (rc)
 487                 goto fail_filesystem;
 488         return 0;
 489
 490 fail_filesystem:
 491         kobject_put(s390_kobj);
 492 fail_hypfs_vm_exit:
 493         hypfs_vm_exit();
 494 fail_hypfs_diag_exit:
 495         hypfs_diag_exit();
 496 fail_dbfs_exit:
 497         hypfs_dbfs_exit();
 498         pr_err("Initialization of hypfs failed with rc=%i\n", rc);
 499         return rc;
 500 }
 501
 502 static void __exit hypfs_exit(void)
 503 {
 504         hypfs_diag_exit();
 505         hypfs_vm_exit();
 506         hypfs_dbfs_exit();
 507         unregister_filesystem(&hypfs_type);
 508         kobject_put(s390_kobj);
 509 }
 510
 511 module_init(hypfs_init)
 512 module_exit(hypfs_exit)
 513
 514 MODULE_LICENSE("GPL");
 515 MODULE_AUTHOR("Michael Holzheu <holzheu@de.ibm.com>");
 516 MODULE_DESCRIPTION("s390 Hypervisor Filesystem");