fc8875186ae80e0c9a966fb1225d0f1e4b664b5b
[linux-3.10.git] / fs / exofs / super.c
1 /*
2  * Copyright (C) 2005, 2006
3  * Avishay Traeger (avishay@gmail.com)
4  * Copyright (C) 2008, 2009
5  * Boaz Harrosh <bharrosh@panasas.com>
6  *
7  * Copyrights for code taken from ext2:
8  *     Copyright (C) 1992, 1993, 1994, 1995
9  *     Remy Card (card@masi.ibp.fr)
10  *     Laboratoire MASI - Institut Blaise Pascal
11  *     Universite Pierre et Marie Curie (Paris VI)
12  *     from
13  *     linux/fs/minix/inode.c
14  *     Copyright (C) 1991, 1992  Linus Torvalds
15  *
16  * This file is part of exofs.
17  *
18  * exofs is free software; you can redistribute it and/or modify
19  * it under the terms of the GNU General Public License as published by
20  * the Free Software Foundation.  Since it is based on ext2, and the only
21  * valid version of GPL for the Linux kernel is version 2, the only valid
22  * version of GPL for exofs is version 2.
23  *
24  * exofs is distributed in the hope that it will be useful,
25  * but WITHOUT ANY WARRANTY; without even the implied warranty of
26  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
27  * GNU General Public License for more details.
28  *
29  * You should have received a copy of the GNU General Public License
30  * along with exofs; if not, write to the Free Software
31  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
32  */
33
34 #include <linux/smp_lock.h>
35 #include <linux/string.h>
36 #include <linux/parser.h>
37 #include <linux/vfs.h>
38 #include <linux/random.h>
39 #include <linux/exportfs.h>
40
41 #include "exofs.h"
42
43 /******************************************************************************
44  * MOUNT OPTIONS
45  *****************************************************************************/
46
47 /*
48  * struct to hold what we get from mount options
49  */
50 struct exofs_mountopt {
51         const char *dev_name;
52         uint64_t pid;
53         int timeout;
54 };
55
56 /*
57  * exofs-specific mount-time options.
58  */
59 enum { Opt_pid, Opt_to, Opt_mkfs, Opt_format, Opt_err };
60
61 /*
62  * Our mount-time options.  These should ideally be 64-bit unsigned, but the
63  * kernel's parsing functions do not currently support that.  32-bit should be
64  * sufficient for most applications now.
65  */
66 static match_table_t tokens = {
67         {Opt_pid, "pid=%u"},
68         {Opt_to, "to=%u"},
69         {Opt_err, NULL}
70 };
71
72 /*
73  * The main option parsing method.  Also makes sure that all of the mandatory
74  * mount options were set.
75  */
76 static int parse_options(char *options, struct exofs_mountopt *opts)
77 {
78         char *p;
79         substring_t args[MAX_OPT_ARGS];
80         int option;
81         bool s_pid = false;
82
83         EXOFS_DBGMSG("parse_options %s\n", options);
84         /* defaults */
85         memset(opts, 0, sizeof(*opts));
86         opts->timeout = BLK_DEFAULT_SG_TIMEOUT;
87
88         while ((p = strsep(&options, ",")) != NULL) {
89                 int token;
90                 char str[32];
91
92                 if (!*p)
93                         continue;
94
95                 token = match_token(p, tokens, args);
96                 switch (token) {
97                 case Opt_pid:
98                         if (0 == match_strlcpy(str, &args[0], sizeof(str)))
99                                 return -EINVAL;
100                         opts->pid = simple_strtoull(str, NULL, 0);
101                         if (opts->pid < EXOFS_MIN_PID) {
102                                 EXOFS_ERR("Partition ID must be >= %u",
103                                           EXOFS_MIN_PID);
104                                 return -EINVAL;
105                         }
106                         s_pid = 1;
107                         break;
108                 case Opt_to:
109                         if (match_int(&args[0], &option))
110                                 return -EINVAL;
111                         if (option <= 0) {
112                                 EXOFS_ERR("Timout must be > 0");
113                                 return -EINVAL;
114                         }
115                         opts->timeout = option * HZ;
116                         break;
117                 }
118         }
119
120         if (!s_pid) {
121                 EXOFS_ERR("Need to specify the following options:\n");
122                 EXOFS_ERR("    -o pid=pid_no_to_use\n");
123                 return -EINVAL;
124         }
125
126         return 0;
127 }
128
129 /******************************************************************************
130  * INODE CACHE
131  *****************************************************************************/
132
133 /*
134  * Our inode cache.  Isn't it pretty?
135  */
136 static struct kmem_cache *exofs_inode_cachep;
137
138 /*
139  * Allocate an inode in the cache
140  */
141 static struct inode *exofs_alloc_inode(struct super_block *sb)
142 {
143         struct exofs_i_info *oi;
144
145         oi = kmem_cache_alloc(exofs_inode_cachep, GFP_KERNEL);
146         if (!oi)
147                 return NULL;
148
149         oi->vfs_inode.i_version = 1;
150         return &oi->vfs_inode;
151 }
152
153 /*
154  * Remove an inode from the cache
155  */
156 static void exofs_destroy_inode(struct inode *inode)
157 {
158         kmem_cache_free(exofs_inode_cachep, exofs_i(inode));
159 }
160
161 /*
162  * Initialize the inode
163  */
164 static void exofs_init_once(void *foo)
165 {
166         struct exofs_i_info *oi = foo;
167
168         inode_init_once(&oi->vfs_inode);
169 }
170
171 /*
172  * Create and initialize the inode cache
173  */
174 static int init_inodecache(void)
175 {
176         exofs_inode_cachep = kmem_cache_create("exofs_inode_cache",
177                                 sizeof(struct exofs_i_info), 0,
178                                 SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD,
179                                 exofs_init_once);
180         if (exofs_inode_cachep == NULL)
181                 return -ENOMEM;
182         return 0;
183 }
184
185 /*
186  * Destroy the inode cache
187  */
188 static void destroy_inodecache(void)
189 {
190         kmem_cache_destroy(exofs_inode_cachep);
191 }
192
193 /******************************************************************************
194  * SUPERBLOCK FUNCTIONS
195  *****************************************************************************/
196 static const struct super_operations exofs_sops;
197 static const struct export_operations exofs_export_ops;
198
199 /*
200  * Write the superblock to the OSD
201  */
202 int exofs_sync_fs(struct super_block *sb, int wait)
203 {
204         struct exofs_sb_info *sbi;
205         struct exofs_fscb *fscb;
206         struct exofs_io_state *ios;
207         int ret = -ENOMEM;
208
209         lock_super(sb);
210         sbi = sb->s_fs_info;
211         fscb = &sbi->s_fscb;
212
213         ret = exofs_get_io_state(&sbi->layout, &ios);
214         if (ret)
215                 goto out;
216
217         /* Note: We only write the changing part of the fscb. .i.e upto the
218          *       the fscb->s_dev_table_oid member. There is no read-modify-write
219          *       here.
220          */
221         ios->length = offsetof(struct exofs_fscb, s_dev_table_oid);
222         memset(fscb, 0, ios->length);
223         fscb->s_nextid = cpu_to_le64(sbi->s_nextid);
224         fscb->s_numfiles = cpu_to_le32(sbi->s_numfiles);
225         fscb->s_magic = cpu_to_le16(sb->s_magic);
226         fscb->s_newfs = 0;
227         fscb->s_version = EXOFS_FSCB_VER;
228
229         ios->obj.id = EXOFS_SUPER_ID;
230         ios->offset = 0;
231         ios->kern_buff = fscb;
232         ios->cred = sbi->s_cred;
233
234         ret = exofs_sbi_write(ios);
235         if (unlikely(ret)) {
236                 EXOFS_ERR("%s: exofs_sbi_write failed.\n", __func__);
237                 goto out;
238         }
239         sb->s_dirt = 0;
240
241 out:
242         EXOFS_DBGMSG("s_nextid=0x%llx ret=%d\n", _LLU(sbi->s_nextid), ret);
243         exofs_put_io_state(ios);
244         unlock_super(sb);
245         return ret;
246 }
247
248 static void exofs_write_super(struct super_block *sb)
249 {
250         if (!(sb->s_flags & MS_RDONLY))
251                 exofs_sync_fs(sb, 1);
252         else
253                 sb->s_dirt = 0;
254 }
255
256 static void _exofs_print_device(const char *msg, const char *dev_path,
257                                 struct osd_dev *od, u64 pid)
258 {
259         const struct osd_dev_info *odi = osduld_device_info(od);
260
261         printk(KERN_NOTICE "exofs: %s %s osd_name-%s pid-0x%llx\n",
262                 msg, dev_path ?: "", odi->osdname, _LLU(pid));
263 }
264
265 void exofs_free_sbi(struct exofs_sb_info *sbi)
266 {
267         while (sbi->layout.s_numdevs) {
268                 int i = --sbi->layout.s_numdevs;
269                 struct osd_dev *od = sbi->layout.s_ods[i];
270
271                 if (od) {
272                         sbi->layout.s_ods[i] = NULL;
273                         osduld_put_device(od);
274                 }
275         }
276         kfree(sbi);
277 }
278
279 /*
280  * This function is called when the vfs is freeing the superblock.  We just
281  * need to free our own part.
282  */
283 static void exofs_put_super(struct super_block *sb)
284 {
285         int num_pend;
286         struct exofs_sb_info *sbi = sb->s_fs_info;
287
288         if (sb->s_dirt)
289                 exofs_write_super(sb);
290
291         /* make sure there are no pending commands */
292         for (num_pend = atomic_read(&sbi->s_curr_pending); num_pend > 0;
293              num_pend = atomic_read(&sbi->s_curr_pending)) {
294                 wait_queue_head_t wq;
295                 init_waitqueue_head(&wq);
296                 wait_event_timeout(wq,
297                                   (atomic_read(&sbi->s_curr_pending) == 0),
298                                   msecs_to_jiffies(100));
299         }
300
301         _exofs_print_device("Unmounting", NULL, sbi->layout.s_ods[0],
302                             sbi->layout.s_pid);
303
304         exofs_free_sbi(sbi);
305         sb->s_fs_info = NULL;
306 }
307
308 static int _read_and_match_data_map(struct exofs_sb_info *sbi, unsigned numdevs,
309                                     struct exofs_device_table *dt)
310 {
311         sbi->data_map.odm_num_comps   =
312                                 le32_to_cpu(dt->dt_data_map.cb_num_comps);
313         sbi->data_map.odm_stripe_unit =
314                                 le64_to_cpu(dt->dt_data_map.cb_stripe_unit);
315         sbi->data_map.odm_group_width =
316                                 le32_to_cpu(dt->dt_data_map.cb_group_width);
317         sbi->data_map.odm_group_depth =
318                                 le32_to_cpu(dt->dt_data_map.cb_group_depth);
319         sbi->data_map.odm_mirror_cnt  =
320                                 le32_to_cpu(dt->dt_data_map.cb_mirror_cnt);
321         sbi->data_map.odm_raid_algorithm  =
322                                 le32_to_cpu(dt->dt_data_map.cb_raid_algorithm);
323
324 /* FIXME: Hard coded mirror only for now. if not so do not mount */
325         if ((sbi->data_map.odm_num_comps != numdevs) ||
326             (sbi->data_map.odm_stripe_unit != EXOFS_BLKSIZE) ||
327             (sbi->data_map.odm_raid_algorithm != PNFS_OSD_RAID_0) ||
328             (sbi->data_map.odm_mirror_cnt != (numdevs - 1)))
329                 return -EINVAL;
330         else
331                 return 0;
332 }
333
334 /* @odi is valid only as long as @fscb_dev is valid */
335 static int exofs_devs_2_odi(struct exofs_dt_device_info *dt_dev,
336                              struct osd_dev_info *odi)
337 {
338         odi->systemid_len = le32_to_cpu(dt_dev->systemid_len);
339         memcpy(odi->systemid, dt_dev->systemid, odi->systemid_len);
340
341         odi->osdname_len = le32_to_cpu(dt_dev->osdname_len);
342         odi->osdname = dt_dev->osdname;
343
344         /* FIXME support long names. Will need a _put function */
345         if (dt_dev->long_name_offset)
346                 return -EINVAL;
347
348         /* Make sure osdname is printable!
349          * mkexofs should give us space for a null-terminator else the
350          * device-table is invalid.
351          */
352         if (unlikely(odi->osdname_len >= sizeof(dt_dev->osdname)))
353                 odi->osdname_len = sizeof(dt_dev->osdname) - 1;
354         dt_dev->osdname[odi->osdname_len] = 0;
355
356         /* If it's all zeros something is bad we read past end-of-obj */
357         return !(odi->systemid_len || odi->osdname_len);
358 }
359
360 static int exofs_read_lookup_dev_table(struct exofs_sb_info **psbi,
361                                        unsigned table_count)
362 {
363         struct exofs_sb_info *sbi = *psbi;
364         struct osd_dev *fscb_od;
365         struct osd_obj_id obj = {.partition = sbi->layout.s_pid,
366                                  .id = EXOFS_DEVTABLE_ID};
367         struct exofs_device_table *dt;
368         unsigned table_bytes = table_count * sizeof(dt->dt_dev_table[0]) +
369                                              sizeof(*dt);
370         unsigned numdevs, i;
371         int ret;
372
373         dt = kmalloc(table_bytes, GFP_KERNEL);
374         if (unlikely(!dt)) {
375                 EXOFS_ERR("ERROR: allocating %x bytes for device table\n",
376                           table_bytes);
377                 return -ENOMEM;
378         }
379
380         fscb_od = sbi->layout.s_ods[0];
381         sbi->layout.s_ods[0] = NULL;
382         sbi->layout.s_numdevs = 0;
383         ret = exofs_read_kern(fscb_od, sbi->s_cred, &obj, 0, dt, table_bytes);
384         if (unlikely(ret)) {
385                 EXOFS_ERR("ERROR: reading device table\n");
386                 goto out;
387         }
388
389         numdevs = le64_to_cpu(dt->dt_num_devices);
390         if (unlikely(!numdevs)) {
391                 ret = -EINVAL;
392                 goto out;
393         }
394         WARN_ON(table_count != numdevs);
395
396         ret = _read_and_match_data_map(sbi, numdevs, dt);
397         if (unlikely(ret))
398                 goto out;
399
400         if (likely(numdevs > 1)) {
401                 unsigned size = numdevs * sizeof(sbi->layout.s_ods[0]);
402
403                 sbi = krealloc(sbi, sizeof(*sbi) + size, GFP_KERNEL);
404                 if (unlikely(!sbi)) {
405                         ret = -ENOMEM;
406                         goto out;
407                 }
408                 memset(&sbi->layout.s_ods[1], 0,
409                        size - sizeof(sbi->layout.s_ods[0]));
410                 *psbi = sbi;
411         }
412
413         for (i = 0; i < numdevs; i++) {
414                 struct exofs_fscb fscb;
415                 struct osd_dev_info odi;
416                 struct osd_dev *od;
417
418                 if (exofs_devs_2_odi(&dt->dt_dev_table[i], &odi)) {
419                         EXOFS_ERR("ERROR: Read all-zeros device entry\n");
420                         ret = -EINVAL;
421                         goto out;
422                 }
423
424                 printk(KERN_NOTICE "Add device[%d]: osd_name-%s\n",
425                        i, odi.osdname);
426
427                 /* On all devices the device table is identical. The user can
428                  * specify any one of the participating devices on the command
429                  * line. We always keep them in device-table order.
430                  */
431                 if (fscb_od && osduld_device_same(fscb_od, &odi)) {
432                         sbi->layout.s_ods[i] = fscb_od;
433                         ++sbi->layout.s_numdevs;
434                         fscb_od = NULL;
435                         continue;
436                 }
437
438                 od = osduld_info_lookup(&odi);
439                 if (unlikely(IS_ERR(od))) {
440                         ret = PTR_ERR(od);
441                         EXOFS_ERR("ERROR: device requested is not found "
442                                   "osd_name-%s =>%d\n", odi.osdname, ret);
443                         goto out;
444                 }
445
446                 sbi->layout.s_ods[i] = od;
447                 ++sbi->layout.s_numdevs;
448
449                 /* Read the fscb of the other devices to make sure the FS
450                  * partition is there.
451                  */
452                 ret = exofs_read_kern(od, sbi->s_cred, &obj, 0, &fscb,
453                                       sizeof(fscb));
454                 if (unlikely(ret)) {
455                         EXOFS_ERR("ERROR: Malformed participating device "
456                                   "error reading fscb osd_name-%s\n",
457                                   odi.osdname);
458                         goto out;
459                 }
460
461                 /* TODO: verify other information is correct and FS-uuid
462                  *       matches. Benny what did you say about device table
463                  *       generation and old devices?
464                  */
465         }
466
467 out:
468         kfree(dt);
469         if (unlikely(!ret && fscb_od)) {
470                 EXOFS_ERR(
471                       "ERROR: Bad device-table container device not present\n");
472                 osduld_put_device(fscb_od);
473                 ret = -EINVAL;
474         }
475
476         return ret;
477 }
478
479 /*
480  * Read the superblock from the OSD and fill in the fields
481  */
482 static int exofs_fill_super(struct super_block *sb, void *data, int silent)
483 {
484         struct inode *root;
485         struct exofs_mountopt *opts = data;
486         struct exofs_sb_info *sbi;      /*extended info                  */
487         struct osd_dev *od;             /* Master device                 */
488         struct exofs_fscb fscb;         /*on-disk superblock info        */
489         struct osd_obj_id obj;
490         unsigned table_count;
491         int ret;
492
493         sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
494         if (!sbi)
495                 return -ENOMEM;
496
497         /* use mount options to fill superblock */
498         od = osduld_path_lookup(opts->dev_name);
499         if (IS_ERR(od)) {
500                 ret = PTR_ERR(od);
501                 goto free_sbi;
502         }
503
504         /* Default layout in case we do not have a device-table */
505         sbi->layout.s_ods[0] = od;
506         sbi->layout.s_numdevs = 1;
507         sbi->layout.s_pid = opts->pid;
508         sbi->s_timeout = opts->timeout;
509
510         /* fill in some other data by hand */
511         memset(sb->s_id, 0, sizeof(sb->s_id));
512         strcpy(sb->s_id, "exofs");
513         sb->s_blocksize = EXOFS_BLKSIZE;
514         sb->s_blocksize_bits = EXOFS_BLKSHIFT;
515         sb->s_maxbytes = MAX_LFS_FILESIZE;
516         atomic_set(&sbi->s_curr_pending, 0);
517         sb->s_bdev = NULL;
518         sb->s_dev = 0;
519
520         obj.partition = sbi->layout.s_pid;
521         obj.id = EXOFS_SUPER_ID;
522         exofs_make_credential(sbi->s_cred, &obj);
523
524         ret = exofs_read_kern(od, sbi->s_cred, &obj, 0, &fscb, sizeof(fscb));
525         if (unlikely(ret))
526                 goto free_sbi;
527
528         sb->s_magic = le16_to_cpu(fscb.s_magic);
529         sbi->s_nextid = le64_to_cpu(fscb.s_nextid);
530         sbi->s_numfiles = le32_to_cpu(fscb.s_numfiles);
531
532         /* make sure what we read from the object store is correct */
533         if (sb->s_magic != EXOFS_SUPER_MAGIC) {
534                 if (!silent)
535                         EXOFS_ERR("ERROR: Bad magic value\n");
536                 ret = -EINVAL;
537                 goto free_sbi;
538         }
539         if (le32_to_cpu(fscb.s_version) != EXOFS_FSCB_VER) {
540                 EXOFS_ERR("ERROR: Bad FSCB version expected-%d got-%d\n",
541                           EXOFS_FSCB_VER, le32_to_cpu(fscb.s_version));
542                 ret = -EINVAL;
543                 goto free_sbi;
544         }
545
546         /* start generation numbers from a random point */
547         get_random_bytes(&sbi->s_next_generation, sizeof(u32));
548         spin_lock_init(&sbi->s_next_gen_lock);
549
550         table_count = le64_to_cpu(fscb.s_dev_table_count);
551         if (table_count) {
552                 ret = exofs_read_lookup_dev_table(&sbi, table_count);
553                 if (unlikely(ret))
554                         goto free_sbi;
555         }
556
557         /* set up operation vectors */
558         sb->s_fs_info = sbi;
559         sb->s_op = &exofs_sops;
560         sb->s_export_op = &exofs_export_ops;
561         root = exofs_iget(sb, EXOFS_ROOT_ID - EXOFS_OBJ_OFF);
562         if (IS_ERR(root)) {
563                 EXOFS_ERR("ERROR: exofs_iget failed\n");
564                 ret = PTR_ERR(root);
565                 goto free_sbi;
566         }
567         sb->s_root = d_alloc_root(root);
568         if (!sb->s_root) {
569                 iput(root);
570                 EXOFS_ERR("ERROR: get root inode failed\n");
571                 ret = -ENOMEM;
572                 goto free_sbi;
573         }
574
575         if (!S_ISDIR(root->i_mode)) {
576                 dput(sb->s_root);
577                 sb->s_root = NULL;
578                 EXOFS_ERR("ERROR: corrupt root inode (mode = %hd)\n",
579                        root->i_mode);
580                 ret = -EINVAL;
581                 goto free_sbi;
582         }
583
584         _exofs_print_device("Mounting", opts->dev_name, sbi->layout.s_ods[0],
585                             sbi->layout.s_pid);
586         return 0;
587
588 free_sbi:
589         EXOFS_ERR("Unable to mount exofs on %s pid=0x%llx err=%d\n",
590                   opts->dev_name, sbi->layout.s_pid, ret);
591         exofs_free_sbi(sbi);
592         return ret;
593 }
594
595 /*
596  * Set up the superblock (calls exofs_fill_super eventually)
597  */
598 static int exofs_get_sb(struct file_system_type *type,
599                           int flags, const char *dev_name,
600                           void *data, struct vfsmount *mnt)
601 {
602         struct exofs_mountopt opts;
603         int ret;
604
605         ret = parse_options(data, &opts);
606         if (ret)
607                 return ret;
608
609         opts.dev_name = dev_name;
610         return get_sb_nodev(type, flags, &opts, exofs_fill_super, mnt);
611 }
612
613 /*
614  * Return information about the file system state in the buffer.  This is used
615  * by the 'df' command, for example.
616  */
617 static int exofs_statfs(struct dentry *dentry, struct kstatfs *buf)
618 {
619         struct super_block *sb = dentry->d_sb;
620         struct exofs_sb_info *sbi = sb->s_fs_info;
621         struct exofs_io_state *ios;
622         struct osd_attr attrs[] = {
623                 ATTR_DEF(OSD_APAGE_PARTITION_QUOTAS,
624                         OSD_ATTR_PQ_CAPACITY_QUOTA, sizeof(__be64)),
625                 ATTR_DEF(OSD_APAGE_PARTITION_INFORMATION,
626                         OSD_ATTR_PI_USED_CAPACITY, sizeof(__be64)),
627         };
628         uint64_t capacity = ULLONG_MAX;
629         uint64_t used = ULLONG_MAX;
630         uint8_t cred_a[OSD_CAP_LEN];
631         int ret;
632
633         ret = exofs_get_io_state(&sbi->layout, &ios);
634         if (ret) {
635                 EXOFS_DBGMSG("exofs_get_io_state failed.\n");
636                 return ret;
637         }
638
639         exofs_make_credential(cred_a, &ios->obj);
640         ios->cred = sbi->s_cred;
641         ios->in_attr = attrs;
642         ios->in_attr_len = ARRAY_SIZE(attrs);
643
644         ret = exofs_sbi_read(ios);
645         if (unlikely(ret))
646                 goto out;
647
648         ret = extract_attr_from_ios(ios, &attrs[0]);
649         if (likely(!ret)) {
650                 capacity = get_unaligned_be64(attrs[0].val_ptr);
651                 if (unlikely(!capacity))
652                         capacity = ULLONG_MAX;
653         } else
654                 EXOFS_DBGMSG("exofs_statfs: get capacity failed.\n");
655
656         ret = extract_attr_from_ios(ios, &attrs[1]);
657         if (likely(!ret))
658                 used = get_unaligned_be64(attrs[1].val_ptr);
659         else
660                 EXOFS_DBGMSG("exofs_statfs: get used-space failed.\n");
661
662         /* fill in the stats buffer */
663         buf->f_type = EXOFS_SUPER_MAGIC;
664         buf->f_bsize = EXOFS_BLKSIZE;
665         buf->f_blocks = capacity >> 9;
666         buf->f_bfree = (capacity - used) >> 9;
667         buf->f_bavail = buf->f_bfree;
668         buf->f_files = sbi->s_numfiles;
669         buf->f_ffree = EXOFS_MAX_ID - sbi->s_numfiles;
670         buf->f_namelen = EXOFS_NAME_LEN;
671
672 out:
673         exofs_put_io_state(ios);
674         return ret;
675 }
676
677 static const struct super_operations exofs_sops = {
678         .alloc_inode    = exofs_alloc_inode,
679         .destroy_inode  = exofs_destroy_inode,
680         .write_inode    = exofs_write_inode,
681         .delete_inode   = exofs_delete_inode,
682         .put_super      = exofs_put_super,
683         .write_super    = exofs_write_super,
684         .sync_fs        = exofs_sync_fs,
685         .statfs         = exofs_statfs,
686 };
687
688 /******************************************************************************
689  * EXPORT OPERATIONS
690  *****************************************************************************/
691
692 struct dentry *exofs_get_parent(struct dentry *child)
693 {
694         unsigned long ino = exofs_parent_ino(child);
695
696         if (!ino)
697                 return NULL;
698
699         return d_obtain_alias(exofs_iget(child->d_inode->i_sb, ino));
700 }
701
702 static struct inode *exofs_nfs_get_inode(struct super_block *sb,
703                 u64 ino, u32 generation)
704 {
705         struct inode *inode;
706
707         inode = exofs_iget(sb, ino);
708         if (IS_ERR(inode))
709                 return ERR_CAST(inode);
710         if (generation && inode->i_generation != generation) {
711                 /* we didn't find the right inode.. */
712                 iput(inode);
713                 return ERR_PTR(-ESTALE);
714         }
715         return inode;
716 }
717
718 static struct dentry *exofs_fh_to_dentry(struct super_block *sb,
719                                 struct fid *fid, int fh_len, int fh_type)
720 {
721         return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
722                                     exofs_nfs_get_inode);
723 }
724
725 static struct dentry *exofs_fh_to_parent(struct super_block *sb,
726                                 struct fid *fid, int fh_len, int fh_type)
727 {
728         return generic_fh_to_parent(sb, fid, fh_len, fh_type,
729                                     exofs_nfs_get_inode);
730 }
731
732 static const struct export_operations exofs_export_ops = {
733         .fh_to_dentry = exofs_fh_to_dentry,
734         .fh_to_parent = exofs_fh_to_parent,
735         .get_parent = exofs_get_parent,
736 };
737
738 /******************************************************************************
739  * INSMOD/RMMOD
740  *****************************************************************************/
741
742 /*
743  * struct that describes this file system
744  */
745 static struct file_system_type exofs_type = {
746         .owner          = THIS_MODULE,
747         .name           = "exofs",
748         .get_sb         = exofs_get_sb,
749         .kill_sb        = generic_shutdown_super,
750 };
751
752 static int __init init_exofs(void)
753 {
754         int err;
755
756         err = init_inodecache();
757         if (err)
758                 goto out;
759
760         err = register_filesystem(&exofs_type);
761         if (err)
762                 goto out_d;
763
764         return 0;
765 out_d:
766         destroy_inodecache();
767 out:
768         return err;
769 }
770
771 static void __exit exit_exofs(void)
772 {
773         unregister_filesystem(&exofs_type);
774         destroy_inodecache();
775 }
776
777 MODULE_AUTHOR("Avishay Traeger <avishay@gmail.com>");
778 MODULE_DESCRIPTION("exofs");
779 MODULE_LICENSE("GPL");
780
781 module_init(init_exofs)
782 module_exit(exit_exofs)