fs/exofs/super.c

   1 /*
   2  * Copyright (C) 2005, 2006
   3  * Avishay Traeger (avishay@gmail.com) (avishay@il.ibm.com)
   4  * Copyright (C) 2005, 2006
   5  * International Business Machines
   6  * Copyright (C) 2008, 2009
   7  * Boaz Harrosh <bharrosh@panasas.com>
   8  *
   9  * Copyrights for code taken from ext2:
  10  *     Copyright (C) 1992, 1993, 1994, 1995
  11  *     Remy Card (card@masi.ibp.fr)
  12  *     Laboratoire MASI - Institut Blaise Pascal
  13  *     Universite Pierre et Marie Curie (Paris VI)
  14  *     from
  15  *     linux/fs/minix/inode.c
  16  *     Copyright (C) 1991, 1992  Linus Torvalds
  17  *
  18  * This file is part of exofs.
  19  *
  20  * exofs is free software; you can redistribute it and/or modify
  21  * it under the terms of the GNU General Public License as published by
  22  * the Free Software Foundation.  Since it is based on ext2, and the only
  23  * valid version of GPL for the Linux kernel is version 2, the only valid
  24  * version of GPL for exofs is version 2.
  25  *
  26  * exofs is distributed in the hope that it will be useful,
  27  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  28  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  29  * GNU General Public License for more details.
  30  *
  31  * You should have received a copy of the GNU General Public License
  32  * along with exofs; if not, write to the Free Software
  33  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  34  */
  35
  36 #include <linux/string.h>
  37 #include <linux/parser.h>
  38 #include <linux/vfs.h>
  39 #include <linux/random.h>
  40 #include <linux/exportfs.h>
  41
  42 #include "exofs.h"
  43
  44 /******************************************************************************
  45  * MOUNT OPTIONS
  46  *****************************************************************************/
  47
  48 /*
  49  * struct to hold what we get from mount options
  50  */
  51 struct exofs_mountopt {
  52         const char *dev_name;
  53         uint64_t pid;
  54         int timeout;
  55 };
  56
  57 /*
  58  * exofs-specific mount-time options.
  59  */
  60 enum { Opt_pid, Opt_to, Opt_mkfs, Opt_format, Opt_err };
  61
  62 /*
  63  * Our mount-time options.  These should ideally be 64-bit unsigned, but the
  64  * kernel's parsing functions do not currently support that.  32-bit should be
  65  * sufficient for most applications now.
  66  */
  67 static match_table_t tokens = {
  68         {Opt_pid, "pid=%u"},
  69         {Opt_to, "to=%u"},
  70         {Opt_err, NULL}
  71 };
  72
  73 /*
  74  * The main option parsing method.  Also makes sure that all of the mandatory
  75  * mount options were set.
  76  */
  77 static int parse_options(char *options, struct exofs_mountopt *opts)
  78 {
  79         char *p;
  80         substring_t args[MAX_OPT_ARGS];
  81         int option;
  82         bool s_pid = false;
  83
  84         EXOFS_DBGMSG("parse_options %s\n", options);
  85         /* defaults */
  86         memset(opts, 0, sizeof(*opts));
  87         opts->timeout = BLK_DEFAULT_SG_TIMEOUT;
  88
  89         while ((p = strsep(&options, ",")) != NULL) {
  90                 int token;
  91                 char str[32];
  92
  93                 if (!*p)
  94                         continue;
  95
  96                 token = match_token(p, tokens, args);
  97                 switch (token) {
  98                 case Opt_pid:
  99                         if (0 == match_strlcpy(str, &args[0], sizeof(str)))
 100                                 return -EINVAL;
 101                         opts->pid = simple_strtoull(str, NULL, 0);
 102                         if (opts->pid < EXOFS_MIN_PID) {
 103                                 EXOFS_ERR("Partition ID must be >= %u",
 104                                           EXOFS_MIN_PID);
 105                                 return -EINVAL;
 106                         }
 107                         s_pid = 1;
 108                         break;
 109                 case Opt_to:
 110                         if (match_int(&args[0], &option))
 111                                 return -EINVAL;
 112                         if (option <= 0) {
 113                                 EXOFS_ERR("Timout must be > 0");
 114                                 return -EINVAL;
 115                         }
 116                         opts->timeout = option * HZ;
 117                         break;
 118                 }
 119         }
 120
 121         if (!s_pid) {
 122                 EXOFS_ERR("Need to specify the following options:\n");
 123                 EXOFS_ERR("    -o pid=pid_no_to_use\n");
 124                 return -EINVAL;
 125         }
 126
 127         return 0;
 128 }
 129
 130 /******************************************************************************
 131  * INODE CACHE
 132  *****************************************************************************/
 133
 134 /*
 135  * Our inode cache.  Isn't it pretty?
 136  */
 137 static struct kmem_cache *exofs_inode_cachep;
 138
 139 /*
 140  * Allocate an inode in the cache
 141  */
 142 static struct inode *exofs_alloc_inode(struct super_block *sb)
 143 {
 144         struct exofs_i_info *oi;
 145
 146         oi = kmem_cache_alloc(exofs_inode_cachep, GFP_KERNEL);
 147         if (!oi)
 148                 return NULL;
 149
 150         oi->vfs_inode.i_version = 1;
 151         return &oi->vfs_inode;
 152 }
 153
 154 /*
 155  * Remove an inode from the cache
 156  */
 157 static void exofs_destroy_inode(struct inode *inode)
 158 {
 159         kmem_cache_free(exofs_inode_cachep, exofs_i(inode));
 160 }
 161
 162 /*
 163  * Initialize the inode
 164  */
 165 static void exofs_init_once(void *foo)
 166 {
 167         struct exofs_i_info *oi = foo;
 168
 169         inode_init_once(&oi->vfs_inode);
 170 }
 171
 172 /*
 173  * Create and initialize the inode cache
 174  */
 175 static int init_inodecache(void)
 176 {
 177         exofs_inode_cachep = kmem_cache_create("exofs_inode_cache",
 178                                 sizeof(struct exofs_i_info), 0,
 179                                 SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD,
 180                                 exofs_init_once);
 181         if (exofs_inode_cachep == NULL)
 182                 return -ENOMEM;
 183         return 0;
 184 }
 185
 186 /*
 187  * Destroy the inode cache
 188  */
 189 static void destroy_inodecache(void)
 190 {
 191         kmem_cache_destroy(exofs_inode_cachep);
 192 }
 193
 194 /******************************************************************************
 195  * SUPERBLOCK FUNCTIONS
 196  *****************************************************************************/
 197 static const struct super_operations exofs_sops;
 198 static const struct export_operations exofs_export_ops;
 199
 200 /*
 201  * Write the superblock to the OSD
 202  */
 203 static void exofs_write_super(struct super_block *sb)
 204 {
 205         struct exofs_sb_info *sbi;
 206         struct exofs_fscb *fscb;
 207         struct osd_request *or;
 208         struct osd_obj_id obj;
 209         int ret;
 210
 211         fscb = kzalloc(sizeof(struct exofs_fscb), GFP_KERNEL);
 212         if (!fscb) {
 213                 EXOFS_ERR("exofs_write_super: memory allocation failed.\n");
 214                 return;
 215         }
 216
 217         lock_kernel();
 218         sbi = sb->s_fs_info;
 219         fscb->s_nextid = cpu_to_le64(sbi->s_nextid);
 220         fscb->s_numfiles = cpu_to_le32(sbi->s_numfiles);
 221         fscb->s_magic = cpu_to_le16(sb->s_magic);
 222         fscb->s_newfs = 0;
 223
 224         or = osd_start_request(sbi->s_dev, GFP_KERNEL);
 225         if (unlikely(!or)) {
 226                 EXOFS_ERR("exofs_write_super: osd_start_request failed.\n");
 227                 goto out;
 228         }
 229
 230         obj.partition = sbi->s_pid;
 231         obj.id = EXOFS_SUPER_ID;
 232         ret = osd_req_write_kern(or, &obj, 0, fscb, sizeof(*fscb));
 233         if (unlikely(ret)) {
 234                 EXOFS_ERR("exofs_write_super: osd_req_write_kern failed.\n");
 235                 goto out;
 236         }
 237
 238         ret = exofs_sync_op(or, sbi->s_timeout, sbi->s_cred);
 239         if (unlikely(ret)) {
 240                 EXOFS_ERR("exofs_write_super: exofs_sync_op failed.\n");
 241                 goto out;
 242         }
 243         sb->s_dirt = 0;
 244
 245 out:
 246         if (or)
 247                 osd_end_request(or);
 248         unlock_kernel();
 249         kfree(fscb);
 250 }
 251
 252 /*
 253  * This function is called when the vfs is freeing the superblock.  We just
 254  * need to free our own part.
 255  */
 256 static void exofs_put_super(struct super_block *sb)
 257 {
 258         int num_pend;
 259         struct exofs_sb_info *sbi = sb->s_fs_info;
 260
 261         /* make sure there are no pending commands */
 262         for (num_pend = atomic_read(&sbi->s_curr_pending); num_pend > 0;
 263              num_pend = atomic_read(&sbi->s_curr_pending)) {
 264                 wait_queue_head_t wq;
 265                 init_waitqueue_head(&wq);
 266                 wait_event_timeout(wq,
 267                                   (atomic_read(&sbi->s_curr_pending) == 0),
 268                                   msecs_to_jiffies(100));
 269         }
 270
 271         osduld_put_device(sbi->s_dev);
 272         kfree(sb->s_fs_info);
 273         sb->s_fs_info = NULL;
 274 }
 275
 276 /*
 277  * Read the superblock from the OSD and fill in the fields
 278  */
 279 static int exofs_fill_super(struct super_block *sb, void *data, int silent)
 280 {
 281         struct inode *root;
 282         struct exofs_mountopt *opts = data;
 283         struct exofs_sb_info *sbi;      /*extended info                  */
 284         struct exofs_fscb fscb;         /*on-disk superblock info        */
 285         struct osd_request *or = NULL;
 286         struct osd_obj_id obj;
 287         int ret;
 288
 289         sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
 290         if (!sbi)
 291                 return -ENOMEM;
 292         sb->s_fs_info = sbi;
 293
 294         /* use mount options to fill superblock */
 295         sbi->s_dev = osduld_path_lookup(opts->dev_name);
 296         if (IS_ERR(sbi->s_dev)) {
 297                 ret = PTR_ERR(sbi->s_dev);
 298                 sbi->s_dev = NULL;
 299                 goto free_sbi;
 300         }
 301
 302         sbi->s_pid = opts->pid;
 303         sbi->s_timeout = opts->timeout;
 304
 305         /* fill in some other data by hand */
 306         memset(sb->s_id, 0, sizeof(sb->s_id));
 307         strcpy(sb->s_id, "exofs");
 308         sb->s_blocksize = EXOFS_BLKSIZE;
 309         sb->s_blocksize_bits = EXOFS_BLKSHIFT;
 310         sb->s_maxbytes = MAX_LFS_FILESIZE;
 311         atomic_set(&sbi->s_curr_pending, 0);
 312         sb->s_bdev = NULL;
 313         sb->s_dev = 0;
 314
 315         /* read data from on-disk superblock object */
 316         obj.partition = sbi->s_pid;
 317         obj.id = EXOFS_SUPER_ID;
 318         exofs_make_credential(sbi->s_cred, &obj);
 319
 320         or = osd_start_request(sbi->s_dev, GFP_KERNEL);
 321         if (unlikely(!or)) {
 322                 if (!silent)
 323                         EXOFS_ERR(
 324                                "exofs_fill_super: osd_start_request failed.\n");
 325                 ret = -ENOMEM;
 326                 goto free_sbi;
 327         }
 328         ret = osd_req_read_kern(or, &obj, 0, &fscb, sizeof(fscb));
 329         if (unlikely(ret)) {
 330                 if (!silent)
 331                         EXOFS_ERR(
 332                                "exofs_fill_super: osd_req_read_kern failed.\n");
 333                 ret = -ENOMEM;
 334                 goto free_sbi;
 335         }
 336
 337         ret = exofs_sync_op(or, sbi->s_timeout, sbi->s_cred);
 338         if (unlikely(ret)) {
 339                 if (!silent)
 340                         EXOFS_ERR("exofs_fill_super: exofs_sync_op failed.\n");
 341                 ret = -EIO;
 342                 goto free_sbi;
 343         }
 344
 345         sb->s_magic = le16_to_cpu(fscb.s_magic);
 346         sbi->s_nextid = le64_to_cpu(fscb.s_nextid);
 347         sbi->s_numfiles = le32_to_cpu(fscb.s_numfiles);
 348
 349         /* make sure what we read from the object store is correct */
 350         if (sb->s_magic != EXOFS_SUPER_MAGIC) {
 351                 if (!silent)
 352                         EXOFS_ERR("ERROR: Bad magic value\n");
 353                 ret = -EINVAL;
 354                 goto free_sbi;
 355         }
 356
 357         /* start generation numbers from a random point */
 358         get_random_bytes(&sbi->s_next_generation, sizeof(u32));
 359         spin_lock_init(&sbi->s_next_gen_lock);
 360
 361         /* set up operation vectors */
 362         sb->s_op = &exofs_sops;
 363         sb->s_export_op = &exofs_export_ops;
 364         root = exofs_iget(sb, EXOFS_ROOT_ID - EXOFS_OBJ_OFF);
 365         if (IS_ERR(root)) {
 366                 EXOFS_ERR("ERROR: exofs_iget failed\n");
 367                 ret = PTR_ERR(root);
 368                 goto free_sbi;
 369         }
 370         sb->s_root = d_alloc_root(root);
 371         if (!sb->s_root) {
 372                 iput(root);
 373                 EXOFS_ERR("ERROR: get root inode failed\n");
 374                 ret = -ENOMEM;
 375                 goto free_sbi;
 376         }
 377
 378         if (!S_ISDIR(root->i_mode)) {
 379                 dput(sb->s_root);
 380                 sb->s_root = NULL;
 381                 EXOFS_ERR("ERROR: corrupt root inode (mode = %hd)\n",
 382                        root->i_mode);
 383                 ret = -EINVAL;
 384                 goto free_sbi;
 385         }
 386
 387         ret = 0;
 388 out:
 389         if (or)
 390                 osd_end_request(or);
 391         return ret;
 392
 393 free_sbi:
 394         osduld_put_device(sbi->s_dev); /* NULL safe */
 395         kfree(sbi);
 396         goto out;
 397 }
 398
 399 /*
 400  * Set up the superblock (calls exofs_fill_super eventually)
 401  */
 402 static int exofs_get_sb(struct file_system_type *type,
 403                           int flags, const char *dev_name,
 404                           void *data, struct vfsmount *mnt)
 405 {
 406         struct exofs_mountopt opts;
 407         int ret;
 408
 409         ret = parse_options(data, &opts);
 410         if (ret)
 411                 return ret;
 412
 413         opts.dev_name = dev_name;
 414         return get_sb_nodev(type, flags, &opts, exofs_fill_super, mnt);
 415 }
 416
 417 /*
 418  * Return information about the file system state in the buffer.  This is used
 419  * by the 'df' command, for example.
 420  */
 421 static int exofs_statfs(struct dentry *dentry, struct kstatfs *buf)
 422 {
 423         struct super_block *sb = dentry->d_sb;
 424         struct exofs_sb_info *sbi = sb->s_fs_info;
 425         struct osd_obj_id obj = {sbi->s_pid, 0};
 426         struct osd_attr attrs[] = {
 427                 ATTR_DEF(OSD_APAGE_PARTITION_QUOTAS,
 428                         OSD_ATTR_PQ_CAPACITY_QUOTA, sizeof(__be64)),
 429                 ATTR_DEF(OSD_APAGE_PARTITION_INFORMATION,
 430                         OSD_ATTR_PI_USED_CAPACITY, sizeof(__be64)),
 431         };
 432         uint64_t capacity = ULLONG_MAX;
 433         uint64_t used = ULLONG_MAX;
 434         struct osd_request *or;
 435         uint8_t cred_a[OSD_CAP_LEN];
 436         int ret;
 437
 438         /* get used/capacity attributes */
 439         exofs_make_credential(cred_a, &obj);
 440
 441         or = osd_start_request(sbi->s_dev, GFP_KERNEL);
 442         if (unlikely(!or)) {
 443                 EXOFS_DBGMSG("exofs_statfs: osd_start_request failed.\n");
 444                 return -ENOMEM;
 445         }
 446
 447         osd_req_get_attributes(or, &obj);
 448         osd_req_add_get_attr_list(or, attrs, ARRAY_SIZE(attrs));
 449         ret = exofs_sync_op(or, sbi->s_timeout, cred_a);
 450         if (unlikely(ret))
 451                 goto out;
 452
 453         ret = extract_attr_from_req(or, &attrs[0]);
 454         if (likely(!ret))
 455                 capacity = get_unaligned_be64(attrs[0].val_ptr);
 456         else
 457                 EXOFS_DBGMSG("exofs_statfs: get capacity failed.\n");
 458
 459         ret = extract_attr_from_req(or, &attrs[1]);
 460         if (likely(!ret))
 461                 used = get_unaligned_be64(attrs[1].val_ptr);
 462         else
 463                 EXOFS_DBGMSG("exofs_statfs: get used-space failed.\n");
 464
 465         /* fill in the stats buffer */
 466         buf->f_type = EXOFS_SUPER_MAGIC;
 467         buf->f_bsize = EXOFS_BLKSIZE;
 468         buf->f_blocks = (capacity >> EXOFS_BLKSHIFT);
 469         buf->f_bfree = ((capacity - used) >> EXOFS_BLKSHIFT);
 470         buf->f_bavail = buf->f_bfree;
 471         buf->f_files = sbi->s_numfiles;
 472         buf->f_ffree = EXOFS_MAX_ID - sbi->s_numfiles;
 473         buf->f_namelen = EXOFS_NAME_LEN;
 474
 475 out:
 476         osd_end_request(or);
 477         return ret;
 478 }
 479
 480 static const struct super_operations exofs_sops = {
 481         .alloc_inode    = exofs_alloc_inode,
 482         .destroy_inode  = exofs_destroy_inode,
 483         .write_inode    = exofs_write_inode,
 484         .delete_inode   = exofs_delete_inode,
 485         .put_super      = exofs_put_super,
 486         .write_super    = exofs_write_super,
 487         .statfs         = exofs_statfs,
 488 };
 489
 490 /******************************************************************************
 491  * EXPORT OPERATIONS
 492  *****************************************************************************/
 493
 494 struct dentry *exofs_get_parent(struct dentry *child)
 495 {
 496         unsigned long ino = exofs_parent_ino(child);
 497
 498         if (!ino)
 499                 return NULL;
 500
 501         return d_obtain_alias(exofs_iget(child->d_inode->i_sb, ino));
 502 }
 503
 504 static struct inode *exofs_nfs_get_inode(struct super_block *sb,
 505                 u64 ino, u32 generation)
 506 {
 507         struct inode *inode;
 508
 509         inode = exofs_iget(sb, ino);
 510         if (IS_ERR(inode))
 511                 return ERR_CAST(inode);
 512         if (generation && inode->i_generation != generation) {
 513                 /* we didn't find the right inode.. */
 514                 iput(inode);
 515                 return ERR_PTR(-ESTALE);
 516         }
 517         return inode;
 518 }
 519
 520 static struct dentry *exofs_fh_to_dentry(struct super_block *sb,
 521                                 struct fid *fid, int fh_len, int fh_type)
 522 {
 523         return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
 524                                     exofs_nfs_get_inode);
 525 }
 526
 527 static struct dentry *exofs_fh_to_parent(struct super_block *sb,
 528                                 struct fid *fid, int fh_len, int fh_type)
 529 {
 530         return generic_fh_to_parent(sb, fid, fh_len, fh_type,
 531                                     exofs_nfs_get_inode);
 532 }
 533
 534 static const struct export_operations exofs_export_ops = {
 535         .fh_to_dentry = exofs_fh_to_dentry,
 536         .fh_to_parent = exofs_fh_to_parent,
 537         .get_parent = exofs_get_parent,
 538 };
 539
 540 /******************************************************************************
 541  * INSMOD/RMMOD
 542  *****************************************************************************/
 543
 544 /*
 545  * struct that describes this file system
 546  */
 547 static struct file_system_type exofs_type = {
 548         .owner          = THIS_MODULE,
 549         .name           = "exofs",
 550         .get_sb         = exofs_get_sb,
 551         .kill_sb        = generic_shutdown_super,
 552 };
 553
 554 static int __init init_exofs(void)
 555 {
 556         int err;
 557
 558         err = init_inodecache();
 559         if (err)
 560                 goto out;
 561
 562         err = register_filesystem(&exofs_type);
 563         if (err)
 564                 goto out_d;
 565
 566         return 0;
 567 out_d:
 568         destroy_inodecache();
 569 out:
 570         return err;
 571 }
 572
 573 static void __exit exit_exofs(void)
 574 {
 575         unregister_filesystem(&exofs_type);
 576         destroy_inodecache();
 577 }
 578
 579 MODULE_AUTHOR("Avishay Traeger <avishay@gmail.com>");
 580 MODULE_DESCRIPTION("exofs");
 581 MODULE_LICENSE("GPL");
 582
 583 module_init(init_exofs)
 584 module_exit(exit_exofs)