kernel/vserver/dlimit.c

   1 /*
   2  *  linux/kernel/vserver/dlimit.c
   3  *
   4  *  Virtual Server: Context Disk Limits
   5  *
   6  *  Copyright (C) 2004-2007  Herbert Pötzl
   7  *
   8  *  V0.01  initial version
   9  *  V0.02  compat32 splitup
  10  *
  11  */
  12
  13 #include <linux/fs.h>
  14 // #include <linux/mnt_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_tag.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, tag_t tag)
  33 {
  34         struct dl_info *new = NULL;
  35
  36         vxdprintk(VXD_CBIT(dlim, 5),
  37                 "alloc_dl_info(%p,%d)*", sb, tag);
  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_tag = tag;
  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, tag, 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_tag = -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, tag_t tag)
  90 {
  91         return ((tag ^ (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_tag);
 107         get_dl_info(dli);
 108         head = &dl_info_hash[__hashval(dli->dl_sb, dli->dl_tag)];
 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_tag);
 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, tag_t tag)
 132 {
 133         struct hlist_head *head = &dl_info_hash[__hashval(sb, tag)];
 134         struct hlist_node *pos;
 135         struct dl_info *dli;
 136
 137         hlist_for_each_entry_rcu(dli, pos, head, dl_hlist) {
 138
 139                 if (dli->dl_tag == tag && dli->dl_sb == sb) {
 140                         return dli;
 141                 }
 142         }
 143         return NULL;
 144 }
 145
 146
 147 struct dl_info *locate_dl_info(struct super_block *sb, tag_t tag)
 148 {
 149         struct dl_info *dli;
 150
 151         rcu_read_lock();
 152         dli = get_dl_info(__lookup_dl_info(sb, tag));
 153         vxdprintk(VXD_CBIT(dlim, 7),
 154                 "locate_dl_info(%p,#%d) = %p", sb, tag, dli);
 155         rcu_read_unlock();
 156         return dli;
 157 }
 158
 159 void rcu_free_dl_info(struct rcu_head *head)
 160 {
 161         struct dl_info *dli = container_of(head, struct dl_info, dl_rcu);
 162         int usecnt, refcnt;
 163
 164         BUG_ON(!dli || !head);
 165
 166         usecnt = atomic_read(&dli->dl_usecnt);
 167         BUG_ON(usecnt < 0);
 168
 169         refcnt = atomic_read(&dli->dl_refcnt);
 170         BUG_ON(refcnt < 0);
 171
 172         vxdprintk(VXD_CBIT(dlim, 3),
 173                 "rcu_free_dl_info(%p)", dli);
 174         if (!usecnt)
 175                 __dealloc_dl_info(dli);
 176         else
 177                 printk("!!! rcu didn't free\n");
 178 }
 179
 180
 181
 182
 183 static int do_addrem_dlimit(uint32_t id, const char __user *name,
 184         uint32_t flags, int add)
 185 {
 186         struct nameidata nd;
 187         int ret;
 188
 189         ret = user_path_walk_link(name, &nd);
 190         if (!ret) {
 191                 struct super_block *sb;
 192                 struct dl_info *dli;
 193
 194                 ret = -EINVAL;
 195                 if (!nd.dentry->d_inode)
 196                         goto out_release;
 197                 if (!(sb = nd.dentry->d_inode->i_sb))
 198                         goto out_release;
 199
 200                 if (add) {
 201                         dli = __alloc_dl_info(sb, id);
 202                         spin_lock(&dl_info_hash_lock);
 203
 204                         ret = -EEXIST;
 205                         if (__lookup_dl_info(sb, id))
 206                                 goto out_unlock;
 207                         __hash_dl_info(dli);
 208                         dli = NULL;
 209                 } else {
 210                         spin_lock(&dl_info_hash_lock);
 211                         dli = __lookup_dl_info(sb, id);
 212
 213                         ret = -ESRCH;
 214                         if (!dli)
 215                                 goto out_unlock;
 216                         __unhash_dl_info(dli);
 217                 }
 218                 ret = 0;
 219         out_unlock:
 220                 spin_unlock(&dl_info_hash_lock);
 221                 if (add && dli)
 222                         __dealloc_dl_info(dli);
 223         out_release:
 224                 path_release(&nd);
 225         }
 226         return ret;
 227 }
 228
 229 int vc_add_dlimit(uint32_t id, void __user *data)
 230 {
 231         struct vcmd_ctx_dlimit_base_v0 vc_data;
 232
 233         if (copy_from_user (&vc_data, data, sizeof(vc_data)))
 234                 return -EFAULT;
 235
 236         return do_addrem_dlimit(id, vc_data.name, vc_data.flags, 1);
 237 }
 238
 239 int vc_rem_dlimit(uint32_t id, void __user *data)
 240 {
 241         struct vcmd_ctx_dlimit_base_v0 vc_data;
 242
 243         if (copy_from_user (&vc_data, data, sizeof(vc_data)))
 244                 return -EFAULT;
 245
 246         return do_addrem_dlimit(id, vc_data.name, vc_data.flags, 0);
 247 }
 248
 249 #ifdef  CONFIG_COMPAT
 250
 251 int vc_add_dlimit_x32(uint32_t id, void __user *data)
 252 {
 253         struct vcmd_ctx_dlimit_base_v0_x32 vc_data;
 254
 255         if (copy_from_user (&vc_data, data, sizeof(vc_data)))
 256                 return -EFAULT;
 257
 258         return do_addrem_dlimit(id,
 259                 compat_ptr(vc_data.name_ptr), vc_data.flags, 1);
 260 }
 261
 262 int vc_rem_dlimit_x32(uint32_t id, void __user *data)
 263 {
 264         struct vcmd_ctx_dlimit_base_v0_x32 vc_data;
 265
 266         if (copy_from_user (&vc_data, data, sizeof(vc_data)))
 267                 return -EFAULT;
 268
 269         return do_addrem_dlimit(id,
 270                 compat_ptr(vc_data.name_ptr), vc_data.flags, 0);
 271 }
 272
 273 #endif  /* CONFIG_COMPAT */
 274
 275
 276 static inline
 277 int do_set_dlimit(uint32_t id, const char __user *name,
 278         uint32_t space_used, uint32_t space_total,
 279         uint32_t inodes_used, uint32_t inodes_total,
 280         uint32_t reserved, uint32_t flags)
 281 {
 282         struct nameidata nd;
 283         int ret;
 284
 285         ret = user_path_walk_link(name, &nd);
 286         if (!ret) {
 287                 struct super_block *sb;
 288                 struct dl_info *dli;
 289
 290                 ret = -EINVAL;
 291                 if (!nd.dentry->d_inode)
 292                         goto out_release;
 293                 if (!(sb = nd.dentry->d_inode->i_sb))
 294                         goto out_release;
 295                 if ((reserved != CDLIM_KEEP &&
 296                         reserved > 100) ||
 297                         (inodes_used != CDLIM_KEEP &&
 298                         inodes_used > inodes_total) ||
 299                         (space_used != CDLIM_KEEP &&
 300                         space_used > space_total))
 301                         goto out_release;
 302
 303                 ret = -ESRCH;
 304                 dli = locate_dl_info(sb, id);
 305                 if (!dli)
 306                         goto out_release;
 307
 308                 spin_lock(&dli->dl_lock);
 309
 310                 if (inodes_used != CDLIM_KEEP)
 311                         dli->dl_inodes_used = inodes_used;
 312                 if (inodes_total != CDLIM_KEEP)
 313                         dli->dl_inodes_total = inodes_total;
 314                 if (space_used != CDLIM_KEEP) {
 315                         dli->dl_space_used = space_used;
 316                         dli->dl_space_used <<= 10;
 317                 }
 318                 if (space_total == CDLIM_INFINITY)
 319                         dli->dl_space_total = DLIM_INFINITY;
 320                 else if (space_total != CDLIM_KEEP) {
 321                         dli->dl_space_total = space_total;
 322                         dli->dl_space_total <<= 10;
 323                 }
 324                 if (reserved != CDLIM_KEEP)
 325                         dli->dl_nrlmult = (1 << 10) * (100 - reserved) / 100;
 326
 327                 spin_unlock(&dli->dl_lock);
 328
 329                 put_dl_info(dli);
 330                 ret = 0;
 331
 332         out_release:
 333                 path_release(&nd);
 334         }
 335         return ret;
 336 }
 337
 338 int vc_set_dlimit(uint32_t id, void __user *data)
 339 {
 340         struct vcmd_ctx_dlimit_v0 vc_data;
 341
 342         if (copy_from_user (&vc_data, data, sizeof(vc_data)))
 343                 return -EFAULT;
 344
 345         return do_set_dlimit(id, vc_data.name,
 346                 vc_data.space_used, vc_data.space_total,
 347                 vc_data.inodes_used, vc_data.inodes_total,
 348                 vc_data.reserved, vc_data.flags);
 349 }
 350
 351 #ifdef  CONFIG_COMPAT
 352
 353 int vc_set_dlimit_x32(uint32_t id, void __user *data)
 354 {
 355         struct vcmd_ctx_dlimit_v0_x32 vc_data;
 356
 357         if (copy_from_user (&vc_data, data, sizeof(vc_data)))
 358                 return -EFAULT;
 359
 360         return do_set_dlimit(id, compat_ptr(vc_data.name_ptr),
 361                 vc_data.space_used, vc_data.space_total,
 362                 vc_data.inodes_used, vc_data.inodes_total,
 363                 vc_data.reserved, vc_data.flags);
 364 }
 365
 366 #endif  /* CONFIG_COMPAT */
 367
 368
 369 static inline
 370 int do_get_dlimit(uint32_t id, const char __user *name,
 371         uint32_t *space_used, uint32_t *space_total,
 372         uint32_t *inodes_used, uint32_t *inodes_total,
 373         uint32_t *reserved, uint32_t *flags)
 374 {
 375         struct nameidata nd;
 376         int ret;
 377
 378         ret = user_path_walk_link(name, &nd);
 379         if (!ret) {
 380                 struct super_block *sb;
 381                 struct dl_info *dli;
 382
 383                 ret = -EINVAL;
 384                 if (!nd.dentry->d_inode)
 385                         goto out_release;
 386                 if (!(sb = nd.dentry->d_inode->i_sb))
 387                         goto out_release;
 388
 389                 ret = -ESRCH;
 390                 dli = locate_dl_info(sb, id);
 391                 if (!dli)
 392                         goto out_release;
 393
 394                 spin_lock(&dli->dl_lock);
 395                 *inodes_used = dli->dl_inodes_used;
 396                 *inodes_total = dli->dl_inodes_total;
 397                 *space_used = dli->dl_space_used >> 10;
 398                 if (dli->dl_space_total == DLIM_INFINITY)
 399                         *space_total = CDLIM_INFINITY;
 400                 else
 401                         *space_total = dli->dl_space_total >> 10;
 402
 403                 *reserved = 100 - ((dli->dl_nrlmult * 100 + 512) >> 10);
 404                 spin_unlock(&dli->dl_lock);
 405
 406                 put_dl_info(dli);
 407                 ret = -EFAULT;
 408
 409                 ret = 0;
 410         out_release:
 411                 path_release(&nd);
 412         }
 413         return ret;
 414 }
 415
 416
 417 int vc_get_dlimit(uint32_t id, void __user *data)
 418 {
 419         struct vcmd_ctx_dlimit_v0 vc_data;
 420         int ret;
 421
 422         if (copy_from_user (&vc_data, data, sizeof(vc_data)))
 423                 return -EFAULT;
 424
 425         ret = do_get_dlimit(id, vc_data.name,
 426                 &vc_data.space_used, &vc_data.space_total,
 427                 &vc_data.inodes_used, &vc_data.inodes_total,
 428                 &vc_data.reserved, &vc_data.flags);
 429         if (ret)
 430                 return ret;
 431
 432         if (copy_to_user(data, &vc_data, sizeof(vc_data)))
 433                 return -EFAULT;
 434         return 0;
 435 }
 436
 437 #ifdef  CONFIG_COMPAT
 438
 439 int vc_get_dlimit_x32(uint32_t id, void __user *data)
 440 {
 441         struct vcmd_ctx_dlimit_v0_x32 vc_data;
 442         int ret;
 443
 444         if (copy_from_user (&vc_data, data, sizeof(vc_data)))
 445                 return -EFAULT;
 446
 447         ret = do_get_dlimit(id, compat_ptr(vc_data.name_ptr),
 448                 &vc_data.space_used, &vc_data.space_total,
 449                 &vc_data.inodes_used, &vc_data.inodes_total,
 450                 &vc_data.reserved, &vc_data.flags);
 451         if (ret)
 452                 return ret;
 453
 454         if (copy_to_user(data, &vc_data, sizeof(vc_data)))
 455                 return -EFAULT;
 456         return 0;
 457 }
 458
 459 #endif  /* CONFIG_COMPAT */
 460
 461
 462 void vx_vsi_statfs(struct super_block *sb, struct kstatfs *buf)
 463 {
 464         struct dl_info *dli;
 465         __u64 blimit, bfree, bavail;
 466         __u32 ifree;
 467
 468         dli = locate_dl_info(sb, dx_current_tag());
 469         if (!dli)
 470                 return;
 471
 472         spin_lock(&dli->dl_lock);
 473         if (dli->dl_inodes_total == (unsigned long)DLIM_INFINITY)
 474                 goto no_ilim;
 475
 476         /* reduce max inodes available to limit */
 477         if (buf->f_files > dli->dl_inodes_total)
 478                 buf->f_files = dli->dl_inodes_total;
 479
 480         ifree = dli->dl_inodes_total - dli->dl_inodes_used;
 481         /* reduce free inodes to min */
 482         if (ifree < buf->f_ffree)
 483                 buf->f_ffree = ifree;
 484
 485 no_ilim:
 486         if (dli->dl_space_total == DLIM_INFINITY)
 487                 goto no_blim;
 488
 489         blimit = dli->dl_space_total >> sb->s_blocksize_bits;
 490
 491         if (dli->dl_space_total < dli->dl_space_used)
 492                 bfree = 0;
 493         else
 494                 bfree = (dli->dl_space_total - dli->dl_space_used)
 495                         >> sb->s_blocksize_bits;
 496
 497         bavail = ((dli->dl_space_total >> 10) * dli->dl_nrlmult);
 498         if (bavail < dli->dl_space_used)
 499                 bavail = 0;
 500         else
 501                 bavail = (bavail - dli->dl_space_used)
 502                         >> sb->s_blocksize_bits;
 503
 504         /* reduce max space available to limit */
 505         if (buf->f_blocks > blimit)
 506                 buf->f_blocks = blimit;
 507
 508         /* reduce free space to min */
 509         if (bfree < buf->f_bfree)
 510                 buf->f_bfree = bfree;
 511
 512         /* reduce avail space to min */
 513         if (bavail < buf->f_bavail)
 514                 buf->f_bavail = bavail;
 515
 516 no_blim:
 517         spin_unlock(&dli->dl_lock);
 518         put_dl_info(dli);
 519
 520         return;
 521 }
 522
 523 #include <linux/module.h>
 524
 525 EXPORT_SYMBOL_GPL(locate_dl_info);
 526 EXPORT_SYMBOL_GPL(rcu_free_dl_info);
 527