kernel/vserver/dlimit.c

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