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/fs.h>
  14 #include <linux/namespace.h>
  15 #include <linux/namei.h>
  16 #include <linux/statfs.h>
  17 #include <linux/compat.h>
  18 #include <linux/vserver/switch.h>
  19 #include <linux/vs_context.h>
  20 #include <linux/vs_dlimit.h>
  21 #include <linux/vserver/dlimit_cmd.h>
  22
  23 #include <asm/errno.h>
  24 #include <asm/uaccess.h>
  25
  26 /*      __alloc_dl_info()
  27
  28         * allocate an initialized dl_info struct
  29         * doesn't make it visible (hash)                        */
  30
  31 static struct dl_info *__alloc_dl_info(struct super_block *sb, xid_t xid)
  32 {
  33         struct dl_info *new = NULL;
  34
  35         vxdprintk(VXD_CBIT(dlim, 5),
  36                 "alloc_dl_info(%p,%d)*", sb, xid);
  37
  38         /* would this benefit from a slab cache? */
  39         new = kmalloc(sizeof(struct dl_info), GFP_KERNEL);
  40         if (!new)
  41                 return 0;
  42
  43         memset (new, 0, sizeof(struct dl_info));
  44         new->dl_xid = xid;
  45         new->dl_sb = sb;
  46         INIT_RCU_HEAD(&new->dl_rcu);
  47         INIT_HLIST_NODE(&new->dl_hlist);
  48         spin_lock_init(&new->dl_lock);
  49         atomic_set(&new->dl_refcnt, 0);
  50         atomic_set(&new->dl_usecnt, 0);
  51
  52         /* rest of init goes here */
  53
  54         vxdprintk(VXD_CBIT(dlim, 4),
  55                 "alloc_dl_info(%p,%d) = %p", sb, xid, new);
  56         return new;
  57 }
  58
  59 /*      __dealloc_dl_info()
  60
  61         * final disposal of dl_info                             */
  62
  63 static void __dealloc_dl_info(struct dl_info *dli)
  64 {
  65         vxdprintk(VXD_CBIT(dlim, 4),
  66                 "dealloc_dl_info(%p)", dli);
  67
  68         dli->dl_hlist.next = LIST_POISON1;
  69         dli->dl_xid = -1;
  70         dli->dl_sb = 0;
  71
  72         BUG_ON(atomic_read(&dli->dl_usecnt));
  73         BUG_ON(atomic_read(&dli->dl_refcnt));
  74
  75         kfree(dli);
  76 }
  77
  78
  79 /*      hash table for dl_info hash */
  80
  81 #define DL_HASH_SIZE    13
  82
  83 struct hlist_head dl_info_hash[DL_HASH_SIZE];
  84
  85 static spinlock_t dl_info_hash_lock = SPIN_LOCK_UNLOCKED;
  86
  87
  88 static inline unsigned int __hashval(struct super_block *sb, xid_t xid)
  89 {
  90         return ((xid ^ (unsigned long)sb) % DL_HASH_SIZE);
  91 }
  92
  93
  94
  95 /*      __hash_dl_info()
  96
  97         * add the dli to the global hash table
  98         * requires the hash_lock to be held                     */
  99
 100 static inline void __hash_dl_info(struct dl_info *dli)
 101 {
 102         struct hlist_head *head;
 103
 104         vxdprintk(VXD_CBIT(dlim, 6),
 105                 "__hash_dl_info: %p[#%d]", dli, dli->dl_xid);
 106         get_dl_info(dli);
 107         head = &dl_info_hash[__hashval(dli->dl_sb, dli->dl_xid)];
 108         hlist_add_head_rcu(&dli->dl_hlist, head);
 109 }
 110
 111 /*      __unhash_dl_info()
 112
 113         * remove the dli from the global hash table
 114         * requires the hash_lock to be held                     */
 115
 116 static inline void __unhash_dl_info(struct dl_info *dli)
 117 {
 118         vxdprintk(VXD_CBIT(dlim, 6),
 119                 "__unhash_dl_info: %p[#%d]", dli, dli->dl_xid);
 120         hlist_del_rcu(&dli->dl_hlist);
 121         put_dl_info(dli);
 122 }
 123
 124
 125 /*      __lookup_dl_info()
 126
 127         * requires the rcu_read_lock()
 128         * doesn't increment the dl_refcnt                       */
 129
 130 static inline struct dl_info *__lookup_dl_info(struct super_block *sb, xid_t xid)
 131 {
 132         struct hlist_head *head = &dl_info_hash[__hashval(sb, xid)];
 133         struct hlist_node *pos;
 134         struct dl_info *dli;
 135
 136         hlist_for_each_entry_rcu(dli, pos, head, dl_hlist) {
 137 //      hlist_for_each_rcu(pos, head) {
 138 //              struct dl_info *dli =
 139 //                      hlist_entry(pos, struct dl_info, dl_hlist);
 140
 141                 if (dli->dl_xid == xid && dli->dl_sb == sb) {
 142                         return dli;
 143                 }
 144         }
 145         return NULL;
 146 }
 147
 148
 149 struct dl_info *locate_dl_info(struct super_block *sb, xid_t xid)
 150 {
 151         struct dl_info *dli;
 152
 153         rcu_read_lock();
 154         dli = get_dl_info(__lookup_dl_info(sb, xid));
 155         vxdprintk(VXD_CBIT(dlim, 7),
 156                 "locate_dl_info(%p,#%d) = %p", sb, xid, dli);
 157         rcu_read_unlock();
 158         return dli;
 159 }
 160
 161 void rcu_free_dl_info(struct rcu_head *head)
 162 {
 163         struct dl_info *dli = container_of(head, struct dl_info, dl_rcu);
 164         int usecnt, refcnt;
 165
 166         BUG_ON(!dli || !head);
 167
 168         usecnt = atomic_read(&dli->dl_usecnt);
 169         BUG_ON(usecnt < 0);
 170
 171         refcnt = atomic_read(&dli->dl_refcnt);
 172         BUG_ON(refcnt < 0);
 173
 174         vxdprintk(VXD_CBIT(dlim, 3),
 175                 "rcu_free_dl_info(%p)", dli);
 176         if (!usecnt)
 177                 __dealloc_dl_info(dli);
 178         else
 179                 printk("!!! rcu didn't free\n");
 180 }
 181
 182
 183
 184
 185 static int do_addrem_dlimit(uint32_t id, const char __user *name,
 186         uint32_t flags, int add)
 187 {
 188         struct nameidata nd;
 189         int ret;
 190
 191         ret = user_path_walk_link(name, &nd);
 192         if (!ret) {
 193                 struct super_block *sb;
 194                 struct dl_info *dli;
 195
 196                 ret = -EINVAL;
 197                 if (!nd.dentry->d_inode)
 198                         goto out_release;
 199                 if (!(sb = nd.dentry->d_inode->i_sb))
 200                         goto out_release;
 201
 202                 if (add) {
 203                         dli = __alloc_dl_info(sb, id);
 204                         spin_lock(&dl_info_hash_lock);
 205
 206                         ret = -EEXIST;
 207                         if (__lookup_dl_info(sb, id))
 208                                 goto out_unlock;
 209                         __hash_dl_info(dli);
 210                         dli = NULL;
 211                 } else {
 212                         spin_lock(&dl_info_hash_lock);
 213                         dli = __lookup_dl_info(sb, id);
 214
 215                         ret = -ESRCH;
 216                         if (!dli)
 217                                 goto out_unlock;
 218                         __unhash_dl_info(dli);
 219                 }
 220                 ret = 0;
 221         out_unlock:
 222                 spin_unlock(&dl_info_hash_lock);
 223                 if (add && dli)
 224                         __dealloc_dl_info(dli);
 225         out_release:
 226                 path_release(&nd);
 227         }
 228         return ret;
 229 }
 230
 231 int vc_add_dlimit(uint32_t id, void __user *data)
 232 {
 233         struct vcmd_ctx_dlimit_base_v0 vc_data;
 234
 235         if (!vx_check(0, VX_ADMIN))
 236                 return -ENOSYS;
 237         if (copy_from_user (&vc_data, data, sizeof(vc_data)))
 238                 return -EFAULT;
 239
 240         return do_addrem_dlimit(id, vc_data.name, vc_data.flags, 1);
 241 }
 242
 243 int vc_rem_dlimit(uint32_t id, void __user *data)
 244 {
 245         struct vcmd_ctx_dlimit_base_v0 vc_data;
 246
 247         if (!vx_check(0, VX_ADMIN))
 248                 return -ENOSYS;
 249         if (copy_from_user (&vc_data, data, sizeof(vc_data)))
 250                 return -EFAULT;
 251
 252         return do_addrem_dlimit(id, vc_data.name, vc_data.flags, 0);
 253 }
 254
 255 #ifdef  CONFIG_COMPAT
 256
 257 int vc_add_dlimit_x32(uint32_t id, void __user *data)
 258 {
 259         struct vcmd_ctx_dlimit_base_v0_x32 vc_data;
 260
 261         if (!vx_check(0, VX_ADMIN))
 262                 return -ENOSYS;
 263         if (copy_from_user (&vc_data, data, sizeof(vc_data)))
 264                 return -EFAULT;
 265
 266         return do_addrem_dlimit(id,
 267                 compat_ptr(vc_data.name_ptr), vc_data.flags, 1);
 268 }
 269
 270 int vc_rem_dlimit_x32(uint32_t id, void __user *data)
 271 {
 272         struct vcmd_ctx_dlimit_base_v0_x32 vc_data;
 273
 274         if (!vx_check(0, VX_ADMIN))
 275                 return -ENOSYS;
 276         if (copy_from_user (&vc_data, data, sizeof(vc_data)))
 277                 return -EFAULT;
 278
 279         return do_addrem_dlimit(id,
 280                 compat_ptr(vc_data.name_ptr), vc_data.flags, 0);
 281 }
 282
 283 #endif  /* CONFIG_COMPAT */
 284
 285
 286 static inline
 287 int do_set_dlimit(uint32_t id, const char __user *name,
 288         uint32_t space_used, uint32_t space_total,
 289         uint32_t inodes_used, uint32_t inodes_total,
 290         uint32_t reserved, uint32_t flags)
 291 {
 292         struct nameidata nd;
 293         int ret;
 294
 295         ret = user_path_walk_link(name, &nd);
 296         if (!ret) {
 297                 struct super_block *sb;
 298                 struct dl_info *dli;
 299
 300                 ret = -EINVAL;
 301                 if (!nd.dentry->d_inode)
 302                         goto out_release;
 303                 if (!(sb = nd.dentry->d_inode->i_sb))
 304                         goto out_release;
 305                 if ((reserved != (uint32_t)CDLIM_KEEP &&
 306                         reserved > 100) ||
 307                         (inodes_used != (uint32_t)CDLIM_KEEP &&
 308                         inodes_used > inodes_total) ||
 309                         (space_used != (uint32_t)CDLIM_KEEP &&
 310                         space_used > space_total))
 311                         goto out_release;
 312
 313                 ret = -ESRCH;
 314                 dli = locate_dl_info(sb, id);
 315                 if (!dli)
 316                         goto out_release;
 317
 318                 spin_lock(&dli->dl_lock);
 319
 320                 if (inodes_used != (uint32_t)CDLIM_KEEP)
 321                         dli->dl_inodes_used = inodes_used;
 322                 if (inodes_total != (uint32_t)CDLIM_KEEP)
 323                         dli->dl_inodes_total = inodes_total;
 324                 if (space_used != (uint32_t)CDLIM_KEEP) {
 325                         dli->dl_space_used = space_used;
 326                         dli->dl_space_used <<= 10;
 327                 }
 328                 if (space_total == (uint32_t)CDLIM_INFINITY)
 329                         dli->dl_space_total = (uint64_t)CDLIM_INFINITY;
 330                 else if (space_total != (uint32_t)CDLIM_KEEP) {
 331                         dli->dl_space_total = space_total;
 332                         dli->dl_space_total <<= 10;
 333                 }
 334                 if (reserved != (uint32_t)CDLIM_KEEP)
 335                         dli->dl_nrlmult = (1 << 10) * (100 - reserved) / 100;
 336
 337                 spin_unlock(&dli->dl_lock);
 338
 339                 put_dl_info(dli);
 340                 ret = 0;
 341
 342         out_release:
 343                 path_release(&nd);
 344         }
 345         return ret;
 346 }
 347
 348 int vc_set_dlimit(uint32_t id, void __user *data)
 349 {
 350         struct vcmd_ctx_dlimit_v0 vc_data;
 351
 352         if (!vx_check(0, VX_ADMIN))
 353                 return -ENOSYS;
 354         if (copy_from_user (&vc_data, data, sizeof(vc_data)))
 355                 return -EFAULT;
 356
 357         return do_set_dlimit(id, vc_data.name,
 358                 vc_data.space_used, vc_data.space_total,
 359                 vc_data.inodes_used, vc_data.inodes_total,
 360                 vc_data.reserved, vc_data.flags);
 361 }
 362
 363 #ifdef  CONFIG_COMPAT
 364
 365 int vc_set_dlimit_x32(uint32_t id, void __user *data)
 366 {
 367         struct vcmd_ctx_dlimit_v0_x32 vc_data;
 368
 369         if (!vx_check(0, VX_ADMIN))
 370                 return -ENOSYS;
 371         if (copy_from_user (&vc_data, data, sizeof(vc_data)))
 372                 return -EFAULT;
 373
 374         return do_set_dlimit(id, compat_ptr(vc_data.name_ptr),
 375                 vc_data.space_used, vc_data.space_total,
 376                 vc_data.inodes_used, vc_data.inodes_total,
 377                 vc_data.reserved, vc_data.flags);
 378 }
 379
 380 #endif  /* CONFIG_COMPAT */
 381
 382
 383 static inline
 384 int do_get_dlimit(uint32_t id, const char __user *name,
 385         uint32_t *space_used, uint32_t *space_total,
 386         uint32_t *inodes_used, uint32_t *inodes_total,
 387         uint32_t *reserved, uint32_t *flags)
 388 {
 389         struct nameidata nd;
 390         int ret;
 391
 392         ret = user_path_walk_link(name, &nd);
 393         if (!ret) {
 394                 struct super_block *sb;
 395                 struct dl_info *dli;
 396
 397                 ret = -EINVAL;
 398                 if (!nd.dentry->d_inode)
 399                         goto out_release;
 400                 if (!(sb = nd.dentry->d_inode->i_sb))
 401                         goto out_release;
 402
 403                 ret = -ESRCH;
 404                 dli = locate_dl_info(sb, id);
 405                 if (!dli)
 406                         goto out_release;
 407
 408                 spin_lock(&dli->dl_lock);
 409                 *inodes_used = dli->dl_inodes_used;
 410                 *inodes_total = dli->dl_inodes_total;
 411                 *space_used = dli->dl_space_used >> 10;
 412                 if (dli->dl_space_total == (uint64_t)CDLIM_INFINITY)
 413                         *space_total = (uint32_t)CDLIM_INFINITY;
 414                 else
 415                         *space_total = dli->dl_space_total >> 10;
 416
 417                 *reserved = 100 - ((dli->dl_nrlmult * 100 + 512) >> 10);
 418                 spin_unlock(&dli->dl_lock);
 419
 420                 put_dl_info(dli);
 421                 ret = -EFAULT;
 422
 423                 ret = 0;
 424         out_release:
 425                 path_release(&nd);
 426         }
 427         return ret;
 428 }
 429
 430
 431 int vc_get_dlimit(uint32_t id, void __user *data)
 432 {
 433         struct vcmd_ctx_dlimit_v0 vc_data;
 434         int ret;
 435
 436         if (!vx_check(0, VX_ADMIN))
 437                 return -ENOSYS;
 438         if (copy_from_user (&vc_data, data, sizeof(vc_data)))
 439                 return -EFAULT;
 440
 441         ret = do_get_dlimit(id, vc_data.name,
 442                 &vc_data.space_used, &vc_data.space_total,
 443                 &vc_data.inodes_used, &vc_data.inodes_total,
 444                 &vc_data.reserved, &vc_data.flags);
 445         if (ret)
 446                 return ret;
 447
 448         if (copy_to_user(data, &vc_data, sizeof(vc_data)))
 449                 return -EFAULT;
 450         return 0;
 451 }
 452
 453 #ifdef  CONFIG_COMPAT
 454
 455 int vc_get_dlimit_x32(uint32_t id, void __user *data)
 456 {
 457         struct vcmd_ctx_dlimit_v0_x32 vc_data;
 458         int ret;
 459
 460         if (!vx_check(0, VX_ADMIN))
 461                 return -ENOSYS;
 462         if (copy_from_user (&vc_data, data, sizeof(vc_data)))
 463                 return -EFAULT;
 464
 465         ret = do_get_dlimit(id, compat_ptr(vc_data.name_ptr),
 466                 &vc_data.space_used, &vc_data.space_total,
 467                 &vc_data.inodes_used, &vc_data.inodes_total,
 468                 &vc_data.reserved, &vc_data.flags);
 469         if (ret)
 470                 return ret;
 471
 472         if (copy_to_user(data, &vc_data, sizeof(vc_data)))
 473                 return -EFAULT;
 474         return 0;
 475 }
 476
 477 #endif  /* CONFIG_COMPAT */
 478
 479
 480 void vx_vsi_statfs(struct super_block *sb, struct kstatfs *buf)
 481 {
 482         struct dl_info *dli;
 483         __u64 blimit, bfree, bavail;
 484         __u32 ifree;
 485
 486         dli = locate_dl_info(sb, vx_current_xid());
 487         if (!dli)
 488                 return;
 489
 490         spin_lock(&dli->dl_lock);
 491         if (dli->dl_inodes_total == (uint32_t)CDLIM_INFINITY)
 492                 goto no_ilim;
 493
 494         /* reduce max inodes available to limit */
 495         if (buf->f_files > dli->dl_inodes_total)
 496                 buf->f_files = dli->dl_inodes_total;
 497
 498         /* inode hack for reiserfs */
 499         if ((buf->f_files == 0) && (dli->dl_inodes_total > 0)) {
 500                 buf->f_files = dli->dl_inodes_total;
 501                 buf->f_ffree = dli->dl_inodes_total;
 502         }
 503
 504         ifree = dli->dl_inodes_total - dli->dl_inodes_used;
 505         /* reduce free inodes to min */
 506         if (ifree < buf->f_ffree)
 507                 buf->f_ffree = ifree;
 508
 509 no_ilim:
 510         if (dli->dl_space_total == (uint64_t)CDLIM_INFINITY)
 511                 goto no_blim;
 512
 513         blimit = dli->dl_space_total >> sb->s_blocksize_bits;
 514
 515         if (dli->dl_space_total < dli->dl_space_used)
 516                 bfree = 0;
 517         else
 518                 bfree = (dli->dl_space_total - dli->dl_space_used)
 519                         >> sb->s_blocksize_bits;
 520
 521         bavail = ((dli->dl_space_total >> 10) * dli->dl_nrlmult);
 522         if (bavail < dli->dl_space_used)
 523                 bavail = 0;
 524         else
 525                 bavail = (bavail - dli->dl_space_used)
 526                         >> sb->s_blocksize_bits;
 527
 528         /* reduce max space available to limit */
 529         if (buf->f_blocks > blimit)
 530                 buf->f_blocks = blimit;
 531
 532         /* reduce free space to min */
 533         if (bfree < buf->f_bfree)
 534                 buf->f_bfree = bfree;
 535
 536         /* reduce avail space to min */
 537         if (bavail < buf->f_bavail)
 538                 buf->f_bavail = bavail;
 539
 540 no_blim:
 541         spin_unlock(&dli->dl_lock);
 542         put_dl_info(dli);
 543
 544         return;
 545 }
 546
 547 #include <linux/module.h>
 548
 549 EXPORT_SYMBOL_GPL(locate_dl_info);
 550 EXPORT_SYMBOL_GPL(rcu_free_dl_info);
 551