kernel/vserver/dlimit.c

   1 /*
   2  *  linux/kernel/vserver/dlimit.c
   3  *
   4  *  Virtual Server: Context Disk Limits
   5  *
   6  *  Copyright (C) 2004-2005  Herbert Pötzl
   7  *
   8  *  V0.01  initial version
   9  *  V0.02  compat32 splitup
  10  *
  11  */
  12
  13 #include <linux/config.h>
  14 #include <linux/fs.h>
  15 #include <linux/namespace.h>
  16 #include <linux/namei.h>
  17 #include <linux/statfs.h>
  18 #include <linux/compat.h>
  19 #include <linux/vserver/switch.h>
  20 #include <linux/vs_context.h>
  21 #include <linux/vs_dlimit.h>
  22 #include <linux/vserver/dlimit_cmd.h>
  23
  24 #include <asm/errno.h>
  25 #include <asm/uaccess.h>
  26
  27 /*      __alloc_dl_info()
  28
  29         * allocate an initialized dl_info struct
  30         * doesn't make it visible (hash)                        */
  31
  32 static struct dl_info *__alloc_dl_info(struct super_block *sb, xid_t xid)
  33 {
  34         struct dl_info *new = NULL;
  35
  36         vxdprintk(VXD_CBIT(dlim, 5),
  37                 "alloc_dl_info(%p,%d)*", sb, xid);
  38
  39         /* would this benefit from a slab cache? */
  40         new = kmalloc(sizeof(struct dl_info), GFP_KERNEL);
  41         if (!new)
  42                 return 0;
  43
  44         memset (new, 0, sizeof(struct dl_info));
  45         new->dl_xid = xid;
  46         new->dl_sb = sb;
  47         INIT_RCU_HEAD(&new->dl_rcu);
  48         INIT_HLIST_NODE(&new->dl_hlist);
  49         spin_lock_init(&new->dl_lock);
  50         atomic_set(&new->dl_refcnt, 0);
  51         atomic_set(&new->dl_usecnt, 0);
  52
  53         /* rest of init goes here */
  54
  55         vxdprintk(VXD_CBIT(dlim, 4),
  56                 "alloc_dl_info(%p,%d) = %p", sb, xid, new);
  57         return new;
  58 }
  59
  60 /*      __dealloc_dl_info()
  61
  62         * final disposal of dl_info                             */
  63
  64 static void __dealloc_dl_info(struct dl_info *dli)
  65 {
  66         vxdprintk(VXD_CBIT(dlim, 4),
  67                 "dealloc_dl_info(%p)", dli);
  68
  69         dli->dl_hlist.next = LIST_POISON1;
  70         dli->dl_xid = -1;
  71         dli->dl_sb = 0;
  72
  73         BUG_ON(atomic_read(&dli->dl_usecnt));
  74         BUG_ON(atomic_read(&dli->dl_refcnt));
  75
  76         kfree(dli);
  77 }
  78
  79
  80 /*      hash table for dl_info hash */
  81
  82 #define DL_HASH_SIZE    13
  83
  84 struct hlist_head dl_info_hash[DL_HASH_SIZE];
  85
  86 static spinlock_t dl_info_hash_lock = SPIN_LOCK_UNLOCKED;
  87
  88
  89 static inline unsigned int __hashval(struct super_block *sb, xid_t xid)
  90 {
  91         return ((xid ^ (unsigned long)sb) % DL_HASH_SIZE);
  92 }
  93
  94
  95
  96 /*      __hash_dl_info()
  97
  98         * add the dli to the global hash table
  99         * requires the hash_lock to be held                     */
 100
 101 static inline void __hash_dl_info(struct dl_info *dli)
 102 {
 103         struct hlist_head *head;
 104
 105         vxdprintk(VXD_CBIT(dlim, 6),
 106                 "__hash_dl_info: %p[#%d]", dli, dli->dl_xid);
 107         get_dl_info(dli);
 108         head = &dl_info_hash[__hashval(dli->dl_sb, dli->dl_xid)];
 109         hlist_add_head_rcu(&dli->dl_hlist, head);
 110 }
 111
 112 /*      __unhash_dl_info()
 113
 114         * remove the dli from the global hash table
 115         * requires the hash_lock to be held                     */
 116
 117 static inline void __unhash_dl_info(struct dl_info *dli)
 118 {
 119         vxdprintk(VXD_CBIT(dlim, 6),
 120                 "__unhash_dl_info: %p[#%d]", dli, dli->dl_xid);
 121         hlist_del_rcu(&dli->dl_hlist);
 122         put_dl_info(dli);
 123 }
 124
 125
 126 /*      __lookup_dl_info()
 127
 128         * requires the rcu_read_lock()
 129         * doesn't increment the dl_refcnt                       */
 130
 131 static inline struct dl_info *__lookup_dl_info(struct super_block *sb, xid_t xid)
 132 {
 133         struct hlist_head *head = &dl_info_hash[__hashval(sb, xid)];
 134         struct hlist_node *pos;
 135
 136         hlist_for_each_rcu(pos, head) {
 137                 struct dl_info *dli =
 138                         hlist_entry(pos, struct dl_info, dl_hlist);
 139
 140                 if (dli->dl_xid == xid && dli->dl_sb == sb) {
 141                         return dli;
 142                 }
 143         }
 144         return NULL;
 145 }
 146
 147
 148 struct dl_info *locate_dl_info(struct super_block *sb, xid_t xid)
 149 {
 150         struct dl_info *dli;
 151
 152         rcu_read_lock();
 153         dli = get_dl_info(__lookup_dl_info(sb, xid));
 154         vxdprintk(VXD_CBIT(dlim, 7),
 155                 "locate_dl_info(%p,#%d) = %p", sb, xid, dli);
 156         rcu_read_unlock();
 157         return dli;
 158 }
 159
 160 void rcu_free_dl_info(struct rcu_head *head)
 161 {
 162         struct dl_info *dli = container_of(head, struct dl_info, dl_rcu);
 163         int usecnt, refcnt;
 164
 165         BUG_ON(!dli || !head);
 166
 167         usecnt = atomic_read(&dli->dl_usecnt);
 168         BUG_ON(usecnt < 0);
 169
 170         refcnt = atomic_read(&dli->dl_refcnt);
 171         BUG_ON(refcnt < 0);
 172
 173         vxdprintk(VXD_CBIT(dlim, 3),
 174                 "rcu_free_dl_info(%p)", dli);
 175         if (!usecnt)
 176                 __dealloc_dl_info(dli);
 177         else
 178                 printk("!!! rcu didn't free\n");
 179 }
 180
 181
 182
 183
 184 int do_addrem_dlimit(uint32_t id, const char __user *name,
 185         uint32_t flags, int add)
 186 {
 187         struct nameidata nd;
 188         int ret;
 189
 190         ret = user_path_walk_link(name, &nd);
 191         if (!ret) {
 192                 struct super_block *sb;
 193                 struct dl_info *dli;
 194
 195                 ret = -EINVAL;
 196                 if (!nd.dentry->d_inode)
 197                         goto out_release;
 198                 if (!(sb = nd.dentry->d_inode->i_sb))
 199                         goto out_release;
 200
 201                 if (add) {
 202                         dli = __alloc_dl_info(sb, id);
 203                         spin_lock(&dl_info_hash_lock);
 204
 205                         ret = -EEXIST;
 206                         if (__lookup_dl_info(sb, id))
 207                                 goto out_unlock;
 208                         __hash_dl_info(dli);
 209                         dli = NULL;
 210                 } else {
 211                         spin_lock(&dl_info_hash_lock);
 212                         dli = __lookup_dl_info(sb, id);
 213
 214                         ret = -ESRCH;
 215                         if (!dli)
 216                                 goto out_unlock;
 217                         __unhash_dl_info(dli);
 218                 }
 219                 ret = 0;
 220         out_unlock:
 221                 spin_unlock(&dl_info_hash_lock);
 222                 if (add && dli)
 223                         __dealloc_dl_info(dli);
 224         out_release:
 225                 path_release(&nd);
 226         }
 227         return ret;
 228 }
 229
 230 int vc_add_dlimit(uint32_t id, void __user *data)
 231 {
 232         struct vcmd_ctx_dlimit_base_v0 vc_data;
 233
 234         if (!vx_check(0, VX_ADMIN))
 235                 return -ENOSYS;
 236         if (copy_from_user (&vc_data, data, sizeof(vc_data)))
 237                 return -EFAULT;
 238
 239         return do_addrem_dlimit(id, vc_data.name, vc_data.flags, 1);
 240 }
 241
 242 int vc_rem_dlimit(uint32_t id, void __user *data)
 243 {
 244         struct vcmd_ctx_dlimit_base_v0 vc_data;
 245
 246         if (!vx_check(0, VX_ADMIN))
 247                 return -ENOSYS;
 248         if (copy_from_user (&vc_data, data, sizeof(vc_data)))
 249                 return -EFAULT;
 250
 251         return do_addrem_dlimit(id, vc_data.name, vc_data.flags, 0);
 252 }
 253
 254 #ifdef  CONFIG_COMPAT
 255
 256 int vc_add_dlimit_x32(uint32_t id, void __user *data)
 257 {
 258         struct vcmd_ctx_dlimit_base_v0_x32 vc_data;
 259
 260         if (!vx_check(0, VX_ADMIN))
 261                 return -ENOSYS;
 262         if (copy_from_user (&vc_data, data, sizeof(vc_data)))
 263                 return -EFAULT;
 264
 265         return do_addrem_dlimit(id,
 266                 compat_ptr(vc_data.name_ptr), vc_data.flags, 1);
 267 }
 268
 269 int vc_rem_dlimit_x32(uint32_t id, void __user *data)
 270 {
 271         struct vcmd_ctx_dlimit_base_v0_x32 vc_data;
 272
 273         if (!vx_check(0, VX_ADMIN))
 274                 return -ENOSYS;
 275         if (copy_from_user (&vc_data, data, sizeof(vc_data)))
 276                 return -EFAULT;
 277
 278         return do_addrem_dlimit(id,
 279                 compat_ptr(vc_data.name_ptr), vc_data.flags, 0);
 280 }
 281
 282 #endif  /* CONFIG_COMPAT */
 283
 284
 285 static inline
 286 int do_set_dlimit(uint32_t id, const char __user *name,
 287         uint32_t space_used, uint32_t space_total,
 288         uint32_t inodes_used, uint32_t inodes_total,
 289         uint32_t reserved, uint32_t flags)
 290 {
 291         struct nameidata nd;
 292         int ret;
 293
 294         ret = user_path_walk_link(name, &nd);
 295         if (!ret) {
 296                 struct super_block *sb;
 297                 struct dl_info *dli;
 298
 299                 ret = -EINVAL;
 300                 if (!nd.dentry->d_inode)
 301                         goto out_release;
 302                 if (!(sb = nd.dentry->d_inode->i_sb))
 303                         goto out_release;
 304                 if ((reserved != (uint32_t)CDLIM_KEEP &&
 305                         reserved > 100) ||
 306                         (inodes_used != (uint32_t)CDLIM_KEEP &&
 307                         inodes_used > inodes_total) ||
 308                         (space_used != (uint32_t)CDLIM_KEEP &&
 309                         space_used > space_total))
 310                         goto out_release;
 311
 312                 ret = -ESRCH;
 313                 dli = locate_dl_info(sb, id);
 314                 if (!dli)
 315                         goto out_release;
 316
 317                 spin_lock(&dli->dl_lock);
 318
 319                 if (inodes_used != (uint32_t)CDLIM_KEEP)
 320                         dli->dl_inodes_used = inodes_used;
 321                 if (inodes_total != (uint32_t)CDLIM_KEEP)
 322                         dli->dl_inodes_total = inodes_total;
 323                 if (space_used != (uint32_t)CDLIM_KEEP) {
 324                         dli->dl_space_used = space_used;
 325                         dli->dl_space_used <<= 10;
 326                 }
 327                 if (space_total == (uint32_t)CDLIM_INFINITY)
 328                         dli->dl_space_total = (uint64_t)CDLIM_INFINITY;
 329                 else if (space_total != (uint32_t)CDLIM_KEEP) {
 330                         dli->dl_space_total = space_total;
 331                         dli->dl_space_total <<= 10;
 332                 }
 333                 if (reserved != (uint32_t)CDLIM_KEEP)
 334                         dli->dl_nrlmult = (1 << 10) * (100 - reserved) / 100;
 335
 336                 spin_unlock(&dli->dl_lock);
 337
 338                 put_dl_info(dli);
 339                 ret = 0;
 340
 341         out_release:
 342                 path_release(&nd);
 343         }
 344         return ret;
 345 }
 346
 347 int vc_set_dlimit(uint32_t id, void __user *data)
 348 {
 349         struct vcmd_ctx_dlimit_v0 vc_data;
 350
 351         if (!vx_check(0, VX_ADMIN))
 352                 return -ENOSYS;
 353         if (copy_from_user (&vc_data, data, sizeof(vc_data)))
 354                 return -EFAULT;
 355
 356         return do_set_dlimit(id, vc_data.name,
 357                 vc_data.space_used, vc_data.space_total,
 358                 vc_data.inodes_used, vc_data.inodes_total,
 359                 vc_data.reserved, vc_data.flags);
 360 }
 361
 362 #ifdef  CONFIG_COMPAT
 363
 364 int vc_set_dlimit_x32(uint32_t id, void __user *data)
 365 {
 366         struct vcmd_ctx_dlimit_v0_x32 vc_data;
 367
 368         if (!vx_check(0, VX_ADMIN))
 369                 return -ENOSYS;
 370         if (copy_from_user (&vc_data, data, sizeof(vc_data)))
 371                 return -EFAULT;
 372
 373         return do_set_dlimit(id, compat_ptr(vc_data.name_ptr),
 374                 vc_data.space_used, vc_data.space_total,
 375                 vc_data.inodes_used, vc_data.inodes_total,
 376                 vc_data.reserved, vc_data.flags);
 377 }
 378
 379 #endif  /* CONFIG_COMPAT */
 380
 381
 382 static inline
 383 int do_get_dlimit(uint32_t id, const char __user *name,
 384         uint32_t *space_used, uint32_t *space_total,
 385         uint32_t *inodes_used, uint32_t *inodes_total,
 386         uint32_t *reserved, uint32_t *flags)
 387 {
 388         struct nameidata nd;
 389         int ret;
 390
 391         ret = user_path_walk_link(name, &nd);
 392         if (!ret) {
 393                 struct super_block *sb;
 394                 struct dl_info *dli;
 395
 396                 ret = -EINVAL;
 397                 if (!nd.dentry->d_inode)
 398                         goto out_release;
 399                 if (!(sb = nd.dentry->d_inode->i_sb))
 400                         goto out_release;
 401
 402                 ret = -ESRCH;
 403                 dli = locate_dl_info(sb, id);
 404                 if (!dli)
 405                         goto out_release;
 406
 407                 spin_lock(&dli->dl_lock);
 408                 *inodes_used = dli->dl_inodes_used;
 409                 *inodes_total = dli->dl_inodes_total;
 410                 *space_used = dli->dl_space_used >> 10;
 411                 if (dli->dl_space_total == (uint64_t)CDLIM_INFINITY)
 412                         *space_total = (uint32_t)CDLIM_INFINITY;
 413                 else
 414                         *space_total = dli->dl_space_total >> 10;
 415
 416                 *reserved = 100 - ((dli->dl_nrlmult * 100 + 512) >> 10);
 417                 spin_unlock(&dli->dl_lock);
 418
 419                 put_dl_info(dli);
 420                 ret = -EFAULT;
 421
 422                 ret = 0;
 423         out_release:
 424                 path_release(&nd);
 425         }
 426         return ret;
 427 }
 428
 429
 430 int vc_get_dlimit(uint32_t id, void __user *data)
 431 {
 432         struct vcmd_ctx_dlimit_v0 vc_data;
 433         int ret;
 434
 435         if (!vx_check(0, VX_ADMIN))
 436                 return -ENOSYS;
 437         if (copy_from_user (&vc_data, data, sizeof(vc_data)))
 438                 return -EFAULT;
 439
 440         ret = do_get_dlimit(id, vc_data.name,
 441                 &vc_data.space_used, &vc_data.space_total,
 442                 &vc_data.inodes_used, &vc_data.inodes_total,
 443                 &vc_data.reserved, &vc_data.flags);
 444         if (ret)
 445                 return ret;
 446
 447         if (copy_to_user(data, &vc_data, sizeof(vc_data)))
 448                 return -EFAULT;
 449         return 0;
 450 }
 451
 452 #ifdef  CONFIG_COMPAT
 453
 454 int vc_get_dlimit_x32(uint32_t id, void __user *data)
 455 {
 456         struct vcmd_ctx_dlimit_v0_x32 vc_data;
 457         int ret;
 458
 459         if (!vx_check(0, VX_ADMIN))
 460                 return -ENOSYS;
 461         if (copy_from_user (&vc_data, data, sizeof(vc_data)))
 462                 return -EFAULT;
 463
 464         ret = do_get_dlimit(id, compat_ptr(vc_data.name_ptr),
 465                 &vc_data.space_used, &vc_data.space_total,
 466                 &vc_data.inodes_used, &vc_data.inodes_total,
 467                 &vc_data.reserved, &vc_data.flags);
 468         if (ret)
 469                 return ret;
 470
 471         if (copy_to_user(data, &vc_data, sizeof(vc_data)))
 472                 return -EFAULT;
 473         return 0;
 474 }
 475
 476 #endif  /* CONFIG_COMPAT */
 477
 478
 479 void vx_vsi_statfs(struct super_block *sb, struct kstatfs *buf)
 480 {
 481         struct dl_info *dli;
 482         __u64 blimit, bfree, bavail;
 483         __u32 ifree;
 484
 485         dli = locate_dl_info(sb, vx_current_xid());
 486         if (!dli)
 487                 return;
 488
 489         spin_lock(&dli->dl_lock);
 490         if (dli->dl_inodes_total == (uint32_t)CDLIM_INFINITY)
 491                 goto no_ilim;
 492
 493         /* reduce max inodes available to limit */
 494         if (buf->f_files > dli->dl_inodes_total)
 495                 buf->f_files = dli->dl_inodes_total;
 496
 497         ifree = dli->dl_inodes_total - dli->dl_inodes_used;
 498         /* reduce free inodes to min */
 499         if (ifree < buf->f_ffree)
 500                 buf->f_ffree = ifree;
 501
 502 no_ilim:
 503         if (dli->dl_space_total == (uint64_t)CDLIM_INFINITY)
 504                 goto no_blim;
 505
 506         blimit = dli->dl_space_total >> sb->s_blocksize_bits;
 507
 508         if (dli->dl_space_total < dli->dl_space_used)
 509                 bfree = 0;
 510         else
 511                 bfree = (dli->dl_space_total - dli->dl_space_used)
 512                         >> sb->s_blocksize_bits;
 513
 514         bavail = ((dli->dl_space_total >> 10) * dli->dl_nrlmult);
 515         if (bavail < dli->dl_space_used)
 516                 bavail = 0;
 517         else
 518                 bavail = (bavail - dli->dl_space_used)
 519                         >> sb->s_blocksize_bits;
 520
 521         /* reduce max space available to limit */
 522         if (buf->f_blocks > blimit)
 523                 buf->f_blocks = blimit;
 524
 525         /* reduce free space to min */
 526         if (bfree < buf->f_bfree)
 527                 buf->f_bfree = bfree;
 528
 529         /* reduce avail space to min */
 530         if (bavail < buf->f_bavail)
 531                 buf->f_bavail = bavail;
 532
 533 no_blim:
 534         spin_unlock(&dli->dl_lock);
 535         put_dl_info(dli);
 536
 537         return;
 538 }
 539
 540 #include <linux/module.h>
 541
 542 EXPORT_SYMBOL_GPL(locate_dl_info);
 543 EXPORT_SYMBOL_GPL(rcu_free_dl_info);
 544