arch/s390/hypfs/inode.c

   1 /*
   2  *  arch/s390/hypfs/inode.c
   3  *    Hypervisor filesystem for Linux on s390.
   4  *
   5  *    Copyright (C) IBM Corp. 2006
   6  *    Author(s): Michael Holzheu <holzheu@de.ibm.com>
   7  */
   8
   9 #include <linux/types.h>
  10 #include <linux/errno.h>
  11 #include <linux/fs.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>
  21 #include "hypfs.h"
  22
  23 #define HYPFS_MAGIC 0x687970    /* ASCII 'hyp' */
  24 #define TMP_SIZE 64             /* size of temporary buffers */
  25
  26 static struct dentry *hypfs_create_update_file(struct super_block *sb,
  27                                                struct dentry *dir);
  28
  29 struct hypfs_sb_info {
  30         uid_t uid;                      /* uid used for files and dirs */
  31         gid_t gid;                      /* gid used for files and dirs */
  32         struct dentry *update_file;     /* file to trigger update */
  33         time_t last_update;             /* last update time in secs since 1970 */
  34         struct mutex lock;              /* lock to protect update process */
  35 };
  36
  37 static const struct file_operations hypfs_file_ops;
  38 static struct file_system_type hypfs_type;
  39 static struct super_operations hypfs_s_ops;
  40
  41 /* start of list of all dentries, which have to be deleted on update */
  42 static struct dentry *hypfs_last_dentry;
  43
  44 static void hypfs_update_update(struct super_block *sb)
  45 {
  46         struct hypfs_sb_info *sb_info = sb->s_fs_info;
  47         struct inode *inode = sb_info->update_file->d_inode;
  48
  49         sb_info->last_update = get_seconds();
  50         inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
  51 }
  52
  53 /* directory tree removal functions */
  54
  55 static void hypfs_add_dentry(struct dentry *dentry)
  56 {
  57         dentry->d_fsdata = hypfs_last_dentry;
  58         hypfs_last_dentry = dentry;
  59 }
  60
  61 static void hypfs_remove(struct dentry *dentry)
  62 {
  63         struct dentry *parent;
  64
  65         parent = dentry->d_parent;
  66         if (S_ISDIR(dentry->d_inode->i_mode))
  67                 simple_rmdir(parent->d_inode, dentry);
  68         else
  69                 simple_unlink(parent->d_inode, dentry);
  70         d_delete(dentry);
  71         dput(dentry);
  72 }
  73
  74 static void hypfs_delete_tree(struct dentry *root)
  75 {
  76         while (hypfs_last_dentry) {
  77                 struct dentry *next_dentry;
  78                 next_dentry = hypfs_last_dentry->d_fsdata;
  79                 hypfs_remove(hypfs_last_dentry);
  80                 hypfs_last_dentry = next_dentry;
  81         }
  82 }
  83
  84 static struct inode *hypfs_make_inode(struct super_block *sb, int mode)
  85 {
  86         struct inode *ret = new_inode(sb);
  87
  88         if (ret) {
  89                 struct hypfs_sb_info *hypfs_info = sb->s_fs_info;
  90                 ret->i_mode = mode;
  91                 ret->i_uid = hypfs_info->uid;
  92                 ret->i_gid = hypfs_info->gid;
  93                 ret->i_blocks = 0;
  94                 ret->i_atime = ret->i_mtime = ret->i_ctime = CURRENT_TIME;
  95                 if (mode & S_IFDIR)
  96                         ret->i_nlink = 2;
  97                 else
  98                         ret->i_nlink = 1;
  99         }
 100         return ret;
 101 }
 102
 103 static void hypfs_drop_inode(struct inode *inode)
 104 {
 105         kfree(inode->i_private);
 106         generic_delete_inode(inode);
 107 }
 108
 109 static int hypfs_open(struct inode *inode, struct file *filp)
 110 {
 111         char *data = filp->f_path.dentry->d_inode->i_private;
 112         struct hypfs_sb_info *fs_info;
 113
 114         if (filp->f_mode & FMODE_WRITE) {
 115                 if (!(inode->i_mode & S_IWUGO))
 116                         return -EACCES;
 117         }
 118         if (filp->f_mode & FMODE_READ) {
 119                 if (!(inode->i_mode & S_IRUGO))
 120                         return -EACCES;
 121         }
 122
 123         fs_info = inode->i_sb->s_fs_info;
 124         if(data) {
 125                 mutex_lock(&fs_info->lock);
 126                 filp->private_data = kstrdup(data, GFP_KERNEL);
 127                 if (!filp->private_data) {
 128                         mutex_unlock(&fs_info->lock);
 129                         return -ENOMEM;
 130                 }
 131                 mutex_unlock(&fs_info->lock);
 132         }
 133         return 0;
 134 }
 135
 136 static ssize_t hypfs_aio_read(struct kiocb *iocb, const struct iovec *iov,
 137                               unsigned long nr_segs, loff_t offset)
 138 {
 139         char *data;
 140         size_t len;
 141         struct file *filp = iocb->ki_filp;
 142         /* XXX: temporary */
 143         char __user *buf = iov[0].iov_base;
 144         size_t count = iov[0].iov_len;
 145
 146         if (nr_segs != 1) {
 147                 count = -EINVAL;
 148                 goto out;
 149         }
 150
 151         data = filp->private_data;
 152         len = strlen(data);
 153         if (offset > len) {
 154                 count = 0;
 155                 goto out;
 156         }
 157         if (count > len - offset)
 158                 count = len - offset;
 159         if (copy_to_user(buf, data + offset, count)) {
 160                 count = -EFAULT;
 161                 goto out;
 162         }
 163         iocb->ki_pos += count;
 164         file_accessed(filp);
 165 out:
 166         return count;
 167 }
 168 static ssize_t hypfs_aio_write(struct kiocb *iocb, const struct iovec *iov,
 169                               unsigned long nr_segs, loff_t offset)
 170 {
 171         int rc;
 172         struct super_block *sb;
 173         struct hypfs_sb_info *fs_info;
 174         size_t count = iov_length(iov, nr_segs);
 175
 176         sb = iocb->ki_filp->f_path.dentry->d_inode->i_sb;
 177         fs_info = sb->s_fs_info;
 178         /*
 179          * Currently we only allow one update per second for two reasons:
 180          * 1. diag 204 is VERY expensive
 181          * 2. If several processes do updates in parallel and then read the
 182          *    hypfs data, the likelihood of collisions is reduced, if we restrict
 183          *    the minimum update interval. A collision occurs, if during the
 184          *    data gathering of one process another process triggers an update
 185          *    If the first process wants to ensure consistent data, it has
 186          *    to restart data collection in this case.
 187          */
 188         mutex_lock(&fs_info->lock);
 189         if (fs_info->last_update == get_seconds()) {
 190                 rc = -EBUSY;
 191                 goto out;
 192         }
 193         hypfs_delete_tree(sb->s_root);
 194         if (MACHINE_IS_VM)
 195                 rc = hypfs_vm_create_files(sb, sb->s_root);
 196         else
 197                 rc = hypfs_diag_create_files(sb, sb->s_root);
 198         if (rc) {
 199                 printk(KERN_ERR "hypfs: Update failed\n");
 200                 hypfs_delete_tree(sb->s_root);
 201                 goto out;
 202         }
 203         hypfs_update_update(sb);
 204         rc = count;
 205 out:
 206         mutex_unlock(&fs_info->lock);
 207         return rc;
 208 }
 209
 210 static int hypfs_release(struct inode *inode, struct file *filp)
 211 {
 212         kfree(filp->private_data);
 213         return 0;
 214 }
 215
 216 enum { opt_uid, opt_gid, opt_err };
 217
 218 static match_table_t hypfs_tokens = {
 219         {opt_uid, "uid=%u"},
 220         {opt_gid, "gid=%u"},
 221         {opt_err, NULL}
 222 };
 223
 224 static int hypfs_parse_options(char *options, struct super_block *sb)
 225 {
 226         char *str;
 227         substring_t args[MAX_OPT_ARGS];
 228
 229         if (!options)
 230                 return 0;
 231         while ((str = strsep(&options, ",")) != NULL) {
 232                 int token, option;
 233                 struct hypfs_sb_info *hypfs_info = sb->s_fs_info;
 234
 235                 if (!*str)
 236                         continue;
 237                 token = match_token(str, hypfs_tokens, args);
 238                 switch (token) {
 239                 case opt_uid:
 240                         if (match_int(&args[0], &option))
 241                                 return -EINVAL;
 242                         hypfs_info->uid = option;
 243                         break;
 244                 case opt_gid:
 245                         if (match_int(&args[0], &option))
 246                                 return -EINVAL;
 247                         hypfs_info->gid = option;
 248                         break;
 249                 case opt_err:
 250                 default:
 251                         printk(KERN_ERR "hypfs: Unrecognized mount option "
 252                                "\"%s\" or missing value\n", str);
 253                         return -EINVAL;
 254                 }
 255         }
 256         return 0;
 257 }
 258
 259 static int hypfs_fill_super(struct super_block *sb, void *data, int silent)
 260 {
 261         struct inode *root_inode;
 262         struct dentry *root_dentry;
 263         int rc = 0;
 264         struct hypfs_sb_info *sbi;
 265
 266         sbi = kzalloc(sizeof(struct hypfs_sb_info), GFP_KERNEL);
 267         if (!sbi)
 268                 return -ENOMEM;
 269         mutex_init(&sbi->lock);
 270         sbi->uid = current->uid;
 271         sbi->gid = current->gid;
 272         sb->s_fs_info = sbi;
 273         sb->s_blocksize = PAGE_CACHE_SIZE;
 274         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
 275         sb->s_magic = HYPFS_MAGIC;
 276         sb->s_op = &hypfs_s_ops;
 277         if (hypfs_parse_options(data, sb)) {
 278                 rc = -EINVAL;
 279                 goto err_alloc;
 280         }
 281         root_inode = hypfs_make_inode(sb, S_IFDIR | 0755);
 282         if (!root_inode) {
 283                 rc = -ENOMEM;
 284                 goto err_alloc;
 285         }
 286         root_inode->i_op = &simple_dir_inode_operations;
 287         root_inode->i_fop = &simple_dir_operations;
 288         root_dentry = d_alloc_root(root_inode);
 289         if (!root_dentry) {
 290                 iput(root_inode);
 291                 rc = -ENOMEM;
 292                 goto err_alloc;
 293         }
 294         if (MACHINE_IS_VM)
 295                 rc = hypfs_vm_create_files(sb, root_dentry);
 296         else
 297                 rc = hypfs_diag_create_files(sb, root_dentry);
 298         if (rc)
 299                 goto err_tree;
 300         sbi->update_file = hypfs_create_update_file(sb, root_dentry);
 301         if (IS_ERR(sbi->update_file)) {
 302                 rc = PTR_ERR(sbi->update_file);
 303                 goto err_tree;
 304         }
 305         hypfs_update_update(sb);
 306         sb->s_root = root_dentry;
 307         return 0;
 308
 309 err_tree:
 310         hypfs_delete_tree(root_dentry);
 311         d_genocide(root_dentry);
 312         dput(root_dentry);
 313 err_alloc:
 314         kfree(sbi);
 315         return rc;
 316 }
 317
 318 static int hypfs_get_super(struct file_system_type *fst, int flags,
 319                         const char *devname, void *data, struct vfsmount *mnt)
 320 {
 321         return get_sb_single(fst, flags, data, hypfs_fill_super, mnt);
 322 }
 323
 324 static void hypfs_kill_super(struct super_block *sb)
 325 {
 326         struct hypfs_sb_info *sb_info = sb->s_fs_info;
 327
 328         if (sb->s_root) {
 329                 hypfs_delete_tree(sb->s_root);
 330                 hypfs_remove(sb_info->update_file);
 331                 kfree(sb->s_fs_info);
 332                 sb->s_fs_info = NULL;
 333         }
 334         kill_litter_super(sb);
 335 }
 336
 337 static struct dentry *hypfs_create_file(struct super_block *sb,
 338                                         struct dentry *parent, const char *name,
 339                                         char *data, mode_t mode)
 340 {
 341         struct dentry *dentry;
 342         struct inode *inode;
 343         struct qstr qname;
 344
 345         qname.name = name;
 346         qname.len = strlen(name);
 347         qname.hash = full_name_hash(name, qname.len);
 348         dentry = lookup_one_len(name, parent, strlen(name));
 349         if (IS_ERR(dentry))
 350                 return ERR_PTR(-ENOMEM);
 351         inode = hypfs_make_inode(sb, mode);
 352         if (!inode) {
 353                 dput(dentry);
 354                 return ERR_PTR(-ENOMEM);
 355         }
 356         if (mode & S_IFREG) {
 357                 inode->i_fop = &hypfs_file_ops;
 358                 if (data)
 359                         inode->i_size = strlen(data);
 360                 else
 361                         inode->i_size = 0;
 362         } else if (mode & S_IFDIR) {
 363                 inode->i_op = &simple_dir_inode_operations;
 364                 inode->i_fop = &simple_dir_operations;
 365                 parent->d_inode->i_nlink++;
 366         } else
 367                 BUG();
 368         inode->i_private = data;
 369         d_instantiate(dentry, inode);
 370         dget(dentry);
 371         return dentry;
 372 }
 373
 374 struct dentry *hypfs_mkdir(struct super_block *sb, struct dentry *parent,
 375                            const char *name)
 376 {
 377         struct dentry *dentry;
 378
 379         dentry = hypfs_create_file(sb, parent, name, NULL, S_IFDIR | DIR_MODE);
 380         if (IS_ERR(dentry))
 381                 return dentry;
 382         hypfs_add_dentry(dentry);
 383         parent->d_inode->i_nlink++;
 384         return dentry;
 385 }
 386
 387 static struct dentry *hypfs_create_update_file(struct super_block *sb,
 388                                                struct dentry *dir)
 389 {
 390         struct dentry *dentry;
 391
 392         dentry = hypfs_create_file(sb, dir, "update", NULL,
 393                                    S_IFREG | UPDATE_FILE_MODE);
 394         /*
 395          * We do not put the update file on the 'delete' list with
 396          * hypfs_add_dentry(), since it should not be removed when the tree
 397          * is updated.
 398          */
 399         return dentry;
 400 }
 401
 402 struct dentry *hypfs_create_u64(struct super_block *sb, struct dentry *dir,
 403                                 const char *name, __u64 value)
 404 {
 405         char *buffer;
 406         char tmp[TMP_SIZE];
 407         struct dentry *dentry;
 408
 409         snprintf(tmp, TMP_SIZE, "%lld\n", (unsigned long long int)value);
 410         buffer = kstrdup(tmp, GFP_KERNEL);
 411         if (!buffer)
 412                 return ERR_PTR(-ENOMEM);
 413         dentry =
 414             hypfs_create_file(sb, dir, name, buffer, S_IFREG | REG_FILE_MODE);
 415         if (IS_ERR(dentry)) {
 416                 kfree(buffer);
 417                 return ERR_PTR(-ENOMEM);
 418         }
 419         hypfs_add_dentry(dentry);
 420         return dentry;
 421 }
 422
 423 struct dentry *hypfs_create_str(struct super_block *sb, struct dentry *dir,
 424                                 const char *name, char *string)
 425 {
 426         char *buffer;
 427         struct dentry *dentry;
 428
 429         buffer = kmalloc(strlen(string) + 2, GFP_KERNEL);
 430         if (!buffer)
 431                 return ERR_PTR(-ENOMEM);
 432         sprintf(buffer, "%s\n", string);
 433         dentry =
 434             hypfs_create_file(sb, dir, name, buffer, S_IFREG | REG_FILE_MODE);
 435         if (IS_ERR(dentry)) {
 436                 kfree(buffer);
 437                 return ERR_PTR(-ENOMEM);
 438         }
 439         hypfs_add_dentry(dentry);
 440         return dentry;
 441 }
 442
 443 static const struct file_operations hypfs_file_ops = {
 444         .open           = hypfs_open,
 445         .release        = hypfs_release,
 446         .read           = do_sync_read,
 447         .write          = do_sync_write,
 448         .aio_read       = hypfs_aio_read,
 449         .aio_write      = hypfs_aio_write,
 450 };
 451
 452 static struct file_system_type hypfs_type = {
 453         .owner          = THIS_MODULE,
 454         .name           = "s390_hypfs",
 455         .get_sb         = hypfs_get_super,
 456         .kill_sb        = hypfs_kill_super
 457 };
 458
 459 static struct super_operations hypfs_s_ops = {
 460         .statfs         = simple_statfs,
 461         .drop_inode     = hypfs_drop_inode,
 462 };
 463
 464 static decl_subsys(s390, NULL, NULL);
 465
 466 static int __init hypfs_init(void)
 467 {
 468         int rc;
 469
 470         if (MACHINE_IS_VM) {
 471                 if (hypfs_vm_init())
 472                         /* no diag 2fc, just exit */
 473                         return -ENODATA;
 474         } else {
 475                 if (hypfs_diag_init()) {
 476                         rc = -ENODATA;
 477                         goto fail_diag;
 478                 }
 479         }
 480         kset_set_kset_s(&s390_subsys, hypervisor_subsys);
 481         rc = subsystem_register(&s390_subsys);
 482         if (rc)
 483                 goto fail_sysfs;
 484         rc = register_filesystem(&hypfs_type);
 485         if (rc)
 486                 goto fail_filesystem;
 487         return 0;
 488
 489 fail_filesystem:
 490         subsystem_unregister(&s390_subsys);
 491 fail_sysfs:
 492         if (!MACHINE_IS_VM)
 493                 hypfs_diag_exit();
 494 fail_diag:
 495         printk(KERN_ERR "hypfs: Initialization failed with rc = %i.\n", rc);
 496         return rc;
 497 }
 498
 499 static void __exit hypfs_exit(void)
 500 {
 501         if (!MACHINE_IS_VM)
 502                 hypfs_diag_exit();
 503         unregister_filesystem(&hypfs_type);
 504         subsystem_unregister(&s390_subsys);
 505 }
 506
 507 module_init(hypfs_init)
 508 module_exit(hypfs_exit)
 509
 510 MODULE_LICENSE("GPL");
 511 MODULE_AUTHOR("Michael Holzheu <holzheu@de.ibm.com>");
 512 MODULE_DESCRIPTION("s390 Hypervisor Filesystem");