xref: /linux/fs/ceph/super.c (revision ec2212088c42ff7d1362629ec26dda4f3e8bdad3)
1 
2 #include <linux/ceph/ceph_debug.h>
3 
4 #include <linux/backing-dev.h>
5 #include <linux/ctype.h>
6 #include <linux/fs.h>
7 #include <linux/inet.h>
8 #include <linux/in6.h>
9 #include <linux/module.h>
10 #include <linux/mount.h>
11 #include <linux/parser.h>
12 #include <linux/sched.h>
13 #include <linux/seq_file.h>
14 #include <linux/slab.h>
15 #include <linux/statfs.h>
16 #include <linux/string.h>
17 
18 #include "super.h"
19 #include "mds_client.h"
20 
21 #include <linux/ceph/decode.h>
22 #include <linux/ceph/mon_client.h>
23 #include <linux/ceph/auth.h>
24 #include <linux/ceph/debugfs.h>
25 
26 /*
27  * Ceph superblock operations
28  *
29  * Handle the basics of mounting, unmounting.
30  */
31 
32 /*
33  * super ops
34  */
35 static void ceph_put_super(struct super_block *s)
36 {
37 	struct ceph_fs_client *fsc = ceph_sb_to_client(s);
38 
39 	dout("put_super\n");
40 	ceph_mdsc_close_sessions(fsc->mdsc);
41 
42 	/*
43 	 * ensure we release the bdi before put_anon_super releases
44 	 * the device name.
45 	 */
46 	if (s->s_bdi == &fsc->backing_dev_info) {
47 		bdi_unregister(&fsc->backing_dev_info);
48 		s->s_bdi = NULL;
49 	}
50 
51 	return;
52 }
53 
54 static int ceph_statfs(struct dentry *dentry, struct kstatfs *buf)
55 {
56 	struct ceph_fs_client *fsc = ceph_inode_to_client(dentry->d_inode);
57 	struct ceph_monmap *monmap = fsc->client->monc.monmap;
58 	struct ceph_statfs st;
59 	u64 fsid;
60 	int err;
61 
62 	dout("statfs\n");
63 	err = ceph_monc_do_statfs(&fsc->client->monc, &st);
64 	if (err < 0)
65 		return err;
66 
67 	/* fill in kstatfs */
68 	buf->f_type = CEPH_SUPER_MAGIC;  /* ?? */
69 
70 	/*
71 	 * express utilization in terms of large blocks to avoid
72 	 * overflow on 32-bit machines.
73 	 */
74 	buf->f_bsize = 1 << CEPH_BLOCK_SHIFT;
75 	buf->f_blocks = le64_to_cpu(st.kb) >> (CEPH_BLOCK_SHIFT-10);
76 	buf->f_bfree = le64_to_cpu(st.kb_avail) >> (CEPH_BLOCK_SHIFT-10);
77 	buf->f_bavail = le64_to_cpu(st.kb_avail) >> (CEPH_BLOCK_SHIFT-10);
78 
79 	buf->f_files = le64_to_cpu(st.num_objects);
80 	buf->f_ffree = -1;
81 	buf->f_namelen = NAME_MAX;
82 	buf->f_frsize = PAGE_CACHE_SIZE;
83 
84 	/* leave fsid little-endian, regardless of host endianness */
85 	fsid = *(u64 *)(&monmap->fsid) ^ *((u64 *)&monmap->fsid + 1);
86 	buf->f_fsid.val[0] = fsid & 0xffffffff;
87 	buf->f_fsid.val[1] = fsid >> 32;
88 
89 	return 0;
90 }
91 
92 
93 static int ceph_sync_fs(struct super_block *sb, int wait)
94 {
95 	struct ceph_fs_client *fsc = ceph_sb_to_client(sb);
96 
97 	if (!wait) {
98 		dout("sync_fs (non-blocking)\n");
99 		ceph_flush_dirty_caps(fsc->mdsc);
100 		dout("sync_fs (non-blocking) done\n");
101 		return 0;
102 	}
103 
104 	dout("sync_fs (blocking)\n");
105 	ceph_osdc_sync(&fsc->client->osdc);
106 	ceph_mdsc_sync(fsc->mdsc);
107 	dout("sync_fs (blocking) done\n");
108 	return 0;
109 }
110 
111 /*
112  * mount options
113  */
114 enum {
115 	Opt_wsize,
116 	Opt_rsize,
117 	Opt_rasize,
118 	Opt_caps_wanted_delay_min,
119 	Opt_caps_wanted_delay_max,
120 	Opt_cap_release_safety,
121 	Opt_readdir_max_entries,
122 	Opt_readdir_max_bytes,
123 	Opt_congestion_kb,
124 	Opt_last_int,
125 	/* int args above */
126 	Opt_snapdirname,
127 	Opt_last_string,
128 	/* string args above */
129 	Opt_dirstat,
130 	Opt_nodirstat,
131 	Opt_rbytes,
132 	Opt_norbytes,
133 	Opt_noasyncreaddir,
134 	Opt_dcache,
135 	Opt_nodcache,
136 	Opt_ino32,
137 };
138 
139 static match_table_t fsopt_tokens = {
140 	{Opt_wsize, "wsize=%d"},
141 	{Opt_rsize, "rsize=%d"},
142 	{Opt_rasize, "rasize=%d"},
143 	{Opt_caps_wanted_delay_min, "caps_wanted_delay_min=%d"},
144 	{Opt_caps_wanted_delay_max, "caps_wanted_delay_max=%d"},
145 	{Opt_cap_release_safety, "cap_release_safety=%d"},
146 	{Opt_readdir_max_entries, "readdir_max_entries=%d"},
147 	{Opt_readdir_max_bytes, "readdir_max_bytes=%d"},
148 	{Opt_congestion_kb, "write_congestion_kb=%d"},
149 	/* int args above */
150 	{Opt_snapdirname, "snapdirname=%s"},
151 	/* string args above */
152 	{Opt_dirstat, "dirstat"},
153 	{Opt_nodirstat, "nodirstat"},
154 	{Opt_rbytes, "rbytes"},
155 	{Opt_norbytes, "norbytes"},
156 	{Opt_noasyncreaddir, "noasyncreaddir"},
157 	{Opt_dcache, "dcache"},
158 	{Opt_nodcache, "nodcache"},
159 	{Opt_ino32, "ino32"},
160 	{-1, NULL}
161 };
162 
163 static int parse_fsopt_token(char *c, void *private)
164 {
165 	struct ceph_mount_options *fsopt = private;
166 	substring_t argstr[MAX_OPT_ARGS];
167 	int token, intval, ret;
168 
169 	token = match_token((char *)c, fsopt_tokens, argstr);
170 	if (token < 0)
171 		return -EINVAL;
172 
173 	if (token < Opt_last_int) {
174 		ret = match_int(&argstr[0], &intval);
175 		if (ret < 0) {
176 			pr_err("bad mount option arg (not int) "
177 			       "at '%s'\n", c);
178 			return ret;
179 		}
180 		dout("got int token %d val %d\n", token, intval);
181 	} else if (token > Opt_last_int && token < Opt_last_string) {
182 		dout("got string token %d val %s\n", token,
183 		     argstr[0].from);
184 	} else {
185 		dout("got token %d\n", token);
186 	}
187 
188 	switch (token) {
189 	case Opt_snapdirname:
190 		kfree(fsopt->snapdir_name);
191 		fsopt->snapdir_name = kstrndup(argstr[0].from,
192 					       argstr[0].to-argstr[0].from,
193 					       GFP_KERNEL);
194 		if (!fsopt->snapdir_name)
195 			return -ENOMEM;
196 		break;
197 
198 		/* misc */
199 	case Opt_wsize:
200 		fsopt->wsize = intval;
201 		break;
202 	case Opt_rsize:
203 		fsopt->rsize = intval;
204 		break;
205 	case Opt_rasize:
206 		fsopt->rasize = intval;
207 		break;
208 	case Opt_caps_wanted_delay_min:
209 		fsopt->caps_wanted_delay_min = intval;
210 		break;
211 	case Opt_caps_wanted_delay_max:
212 		fsopt->caps_wanted_delay_max = intval;
213 		break;
214 	case Opt_readdir_max_entries:
215 		fsopt->max_readdir = intval;
216 		break;
217 	case Opt_readdir_max_bytes:
218 		fsopt->max_readdir_bytes = intval;
219 		break;
220 	case Opt_congestion_kb:
221 		fsopt->congestion_kb = intval;
222 		break;
223 	case Opt_dirstat:
224 		fsopt->flags |= CEPH_MOUNT_OPT_DIRSTAT;
225 		break;
226 	case Opt_nodirstat:
227 		fsopt->flags &= ~CEPH_MOUNT_OPT_DIRSTAT;
228 		break;
229 	case Opt_rbytes:
230 		fsopt->flags |= CEPH_MOUNT_OPT_RBYTES;
231 		break;
232 	case Opt_norbytes:
233 		fsopt->flags &= ~CEPH_MOUNT_OPT_RBYTES;
234 		break;
235 	case Opt_noasyncreaddir:
236 		fsopt->flags |= CEPH_MOUNT_OPT_NOASYNCREADDIR;
237 		break;
238 	case Opt_dcache:
239 		fsopt->flags |= CEPH_MOUNT_OPT_DCACHE;
240 		break;
241 	case Opt_nodcache:
242 		fsopt->flags &= ~CEPH_MOUNT_OPT_DCACHE;
243 		break;
244 	case Opt_ino32:
245 		fsopt->flags |= CEPH_MOUNT_OPT_INO32;
246 		break;
247 	default:
248 		BUG_ON(token);
249 	}
250 	return 0;
251 }
252 
253 static void destroy_mount_options(struct ceph_mount_options *args)
254 {
255 	dout("destroy_mount_options %p\n", args);
256 	kfree(args->snapdir_name);
257 	kfree(args);
258 }
259 
260 static int strcmp_null(const char *s1, const char *s2)
261 {
262 	if (!s1 && !s2)
263 		return 0;
264 	if (s1 && !s2)
265 		return -1;
266 	if (!s1 && s2)
267 		return 1;
268 	return strcmp(s1, s2);
269 }
270 
271 static int compare_mount_options(struct ceph_mount_options *new_fsopt,
272 				 struct ceph_options *new_opt,
273 				 struct ceph_fs_client *fsc)
274 {
275 	struct ceph_mount_options *fsopt1 = new_fsopt;
276 	struct ceph_mount_options *fsopt2 = fsc->mount_options;
277 	int ofs = offsetof(struct ceph_mount_options, snapdir_name);
278 	int ret;
279 
280 	ret = memcmp(fsopt1, fsopt2, ofs);
281 	if (ret)
282 		return ret;
283 
284 	ret = strcmp_null(fsopt1->snapdir_name, fsopt2->snapdir_name);
285 	if (ret)
286 		return ret;
287 
288 	return ceph_compare_options(new_opt, fsc->client);
289 }
290 
291 static int parse_mount_options(struct ceph_mount_options **pfsopt,
292 			       struct ceph_options **popt,
293 			       int flags, char *options,
294 			       const char *dev_name,
295 			       const char **path)
296 {
297 	struct ceph_mount_options *fsopt;
298 	const char *dev_name_end;
299 	int err = -ENOMEM;
300 
301 	fsopt = kzalloc(sizeof(*fsopt), GFP_KERNEL);
302 	if (!fsopt)
303 		return -ENOMEM;
304 
305 	dout("parse_mount_options %p, dev_name '%s'\n", fsopt, dev_name);
306 
307 	fsopt->sb_flags = flags;
308 	fsopt->flags = CEPH_MOUNT_OPT_DEFAULT;
309 
310 	fsopt->rsize = CEPH_RSIZE_DEFAULT;
311 	fsopt->rasize = CEPH_RASIZE_DEFAULT;
312 	fsopt->snapdir_name = kstrdup(CEPH_SNAPDIRNAME_DEFAULT, GFP_KERNEL);
313 	fsopt->caps_wanted_delay_min = CEPH_CAPS_WANTED_DELAY_MIN_DEFAULT;
314 	fsopt->caps_wanted_delay_max = CEPH_CAPS_WANTED_DELAY_MAX_DEFAULT;
315 	fsopt->cap_release_safety = CEPH_CAP_RELEASE_SAFETY_DEFAULT;
316 	fsopt->max_readdir = CEPH_MAX_READDIR_DEFAULT;
317 	fsopt->max_readdir_bytes = CEPH_MAX_READDIR_BYTES_DEFAULT;
318 	fsopt->congestion_kb = default_congestion_kb();
319 
320 	/* ip1[:port1][,ip2[:port2]...]:/subdir/in/fs */
321 	err = -EINVAL;
322 	if (!dev_name)
323 		goto out;
324 	*path = strstr(dev_name, ":/");
325 	if (*path == NULL) {
326 		pr_err("device name is missing path (no :/ in %s)\n",
327 				dev_name);
328 		goto out;
329 	}
330 	dev_name_end = *path;
331 	dout("device name '%.*s'\n", (int)(dev_name_end - dev_name), dev_name);
332 
333 	/* path on server */
334 	*path += 2;
335 	dout("server path '%s'\n", *path);
336 
337 	err = ceph_parse_options(popt, options, dev_name, dev_name_end,
338 				 parse_fsopt_token, (void *)fsopt);
339 	if (err)
340 		goto out;
341 
342 	/* success */
343 	*pfsopt = fsopt;
344 	return 0;
345 
346 out:
347 	destroy_mount_options(fsopt);
348 	return err;
349 }
350 
351 /**
352  * ceph_show_options - Show mount options in /proc/mounts
353  * @m: seq_file to write to
354  * @root: root of that (sub)tree
355  */
356 static int ceph_show_options(struct seq_file *m, struct dentry *root)
357 {
358 	struct ceph_fs_client *fsc = ceph_sb_to_client(root->d_sb);
359 	struct ceph_mount_options *fsopt = fsc->mount_options;
360 	struct ceph_options *opt = fsc->client->options;
361 
362 	if (opt->flags & CEPH_OPT_FSID)
363 		seq_printf(m, ",fsid=%pU", &opt->fsid);
364 	if (opt->flags & CEPH_OPT_NOSHARE)
365 		seq_puts(m, ",noshare");
366 	if (opt->flags & CEPH_OPT_NOCRC)
367 		seq_puts(m, ",nocrc");
368 
369 	if (opt->name)
370 		seq_printf(m, ",name=%s", opt->name);
371 	if (opt->key)
372 		seq_puts(m, ",secret=<hidden>");
373 
374 	if (opt->mount_timeout != CEPH_MOUNT_TIMEOUT_DEFAULT)
375 		seq_printf(m, ",mount_timeout=%d", opt->mount_timeout);
376 	if (opt->osd_idle_ttl != CEPH_OSD_IDLE_TTL_DEFAULT)
377 		seq_printf(m, ",osd_idle_ttl=%d", opt->osd_idle_ttl);
378 	if (opt->osd_timeout != CEPH_OSD_TIMEOUT_DEFAULT)
379 		seq_printf(m, ",osdtimeout=%d", opt->osd_timeout);
380 	if (opt->osd_keepalive_timeout != CEPH_OSD_KEEPALIVE_DEFAULT)
381 		seq_printf(m, ",osdkeepalivetimeout=%d",
382 			   opt->osd_keepalive_timeout);
383 
384 	if (fsopt->flags & CEPH_MOUNT_OPT_DIRSTAT)
385 		seq_puts(m, ",dirstat");
386 	if ((fsopt->flags & CEPH_MOUNT_OPT_RBYTES) == 0)
387 		seq_puts(m, ",norbytes");
388 	if (fsopt->flags & CEPH_MOUNT_OPT_NOASYNCREADDIR)
389 		seq_puts(m, ",noasyncreaddir");
390 	if (fsopt->flags & CEPH_MOUNT_OPT_DCACHE)
391 		seq_puts(m, ",dcache");
392 	else
393 		seq_puts(m, ",nodcache");
394 
395 	if (fsopt->wsize)
396 		seq_printf(m, ",wsize=%d", fsopt->wsize);
397 	if (fsopt->rsize != CEPH_RSIZE_DEFAULT)
398 		seq_printf(m, ",rsize=%d", fsopt->rsize);
399 	if (fsopt->rasize != CEPH_RASIZE_DEFAULT)
400 		seq_printf(m, ",rasize=%d", fsopt->rasize);
401 	if (fsopt->congestion_kb != default_congestion_kb())
402 		seq_printf(m, ",write_congestion_kb=%d", fsopt->congestion_kb);
403 	if (fsopt->caps_wanted_delay_min != CEPH_CAPS_WANTED_DELAY_MIN_DEFAULT)
404 		seq_printf(m, ",caps_wanted_delay_min=%d",
405 			 fsopt->caps_wanted_delay_min);
406 	if (fsopt->caps_wanted_delay_max != CEPH_CAPS_WANTED_DELAY_MAX_DEFAULT)
407 		seq_printf(m, ",caps_wanted_delay_max=%d",
408 			   fsopt->caps_wanted_delay_max);
409 	if (fsopt->cap_release_safety != CEPH_CAP_RELEASE_SAFETY_DEFAULT)
410 		seq_printf(m, ",cap_release_safety=%d",
411 			   fsopt->cap_release_safety);
412 	if (fsopt->max_readdir != CEPH_MAX_READDIR_DEFAULT)
413 		seq_printf(m, ",readdir_max_entries=%d", fsopt->max_readdir);
414 	if (fsopt->max_readdir_bytes != CEPH_MAX_READDIR_BYTES_DEFAULT)
415 		seq_printf(m, ",readdir_max_bytes=%d", fsopt->max_readdir_bytes);
416 	if (strcmp(fsopt->snapdir_name, CEPH_SNAPDIRNAME_DEFAULT))
417 		seq_printf(m, ",snapdirname=%s", fsopt->snapdir_name);
418 	return 0;
419 }
420 
421 /*
422  * handle any mon messages the standard library doesn't understand.
423  * return error if we don't either.
424  */
425 static int extra_mon_dispatch(struct ceph_client *client, struct ceph_msg *msg)
426 {
427 	struct ceph_fs_client *fsc = client->private;
428 	int type = le16_to_cpu(msg->hdr.type);
429 
430 	switch (type) {
431 	case CEPH_MSG_MDS_MAP:
432 		ceph_mdsc_handle_map(fsc->mdsc, msg);
433 		return 0;
434 
435 	default:
436 		return -1;
437 	}
438 }
439 
440 /*
441  * create a new fs client
442  */
443 static struct ceph_fs_client *create_fs_client(struct ceph_mount_options *fsopt,
444 					struct ceph_options *opt)
445 {
446 	struct ceph_fs_client *fsc;
447 	const unsigned supported_features =
448 		CEPH_FEATURE_FLOCK |
449 		CEPH_FEATURE_DIRLAYOUTHASH;
450 	const unsigned required_features = 0;
451 	int err = -ENOMEM;
452 
453 	fsc = kzalloc(sizeof(*fsc), GFP_KERNEL);
454 	if (!fsc)
455 		return ERR_PTR(-ENOMEM);
456 
457 	fsc->client = ceph_create_client(opt, fsc, supported_features,
458 					 required_features);
459 	if (IS_ERR(fsc->client)) {
460 		err = PTR_ERR(fsc->client);
461 		goto fail;
462 	}
463 	fsc->client->extra_mon_dispatch = extra_mon_dispatch;
464 	fsc->client->monc.want_mdsmap = 1;
465 
466 	fsc->mount_options = fsopt;
467 
468 	fsc->sb = NULL;
469 	fsc->mount_state = CEPH_MOUNT_MOUNTING;
470 
471 	atomic_long_set(&fsc->writeback_count, 0);
472 
473 	err = bdi_init(&fsc->backing_dev_info);
474 	if (err < 0)
475 		goto fail_client;
476 
477 	err = -ENOMEM;
478 	/*
479 	 * The number of concurrent works can be high but they don't need
480 	 * to be processed in parallel, limit concurrency.
481 	 */
482 	fsc->wb_wq = alloc_workqueue("ceph-writeback", 0, 1);
483 	if (fsc->wb_wq == NULL)
484 		goto fail_bdi;
485 	fsc->pg_inv_wq = alloc_workqueue("ceph-pg-invalid", 0, 1);
486 	if (fsc->pg_inv_wq == NULL)
487 		goto fail_wb_wq;
488 	fsc->trunc_wq = alloc_workqueue("ceph-trunc", 0, 1);
489 	if (fsc->trunc_wq == NULL)
490 		goto fail_pg_inv_wq;
491 
492 	/* set up mempools */
493 	err = -ENOMEM;
494 	fsc->wb_pagevec_pool = mempool_create_kmalloc_pool(10,
495 			      fsc->mount_options->wsize >> PAGE_CACHE_SHIFT);
496 	if (!fsc->wb_pagevec_pool)
497 		goto fail_trunc_wq;
498 
499 	/* caps */
500 	fsc->min_caps = fsopt->max_readdir;
501 
502 	return fsc;
503 
504 fail_trunc_wq:
505 	destroy_workqueue(fsc->trunc_wq);
506 fail_pg_inv_wq:
507 	destroy_workqueue(fsc->pg_inv_wq);
508 fail_wb_wq:
509 	destroy_workqueue(fsc->wb_wq);
510 fail_bdi:
511 	bdi_destroy(&fsc->backing_dev_info);
512 fail_client:
513 	ceph_destroy_client(fsc->client);
514 fail:
515 	kfree(fsc);
516 	return ERR_PTR(err);
517 }
518 
519 static void destroy_fs_client(struct ceph_fs_client *fsc)
520 {
521 	dout("destroy_fs_client %p\n", fsc);
522 
523 	destroy_workqueue(fsc->wb_wq);
524 	destroy_workqueue(fsc->pg_inv_wq);
525 	destroy_workqueue(fsc->trunc_wq);
526 
527 	bdi_destroy(&fsc->backing_dev_info);
528 
529 	mempool_destroy(fsc->wb_pagevec_pool);
530 
531 	destroy_mount_options(fsc->mount_options);
532 
533 	ceph_fs_debugfs_cleanup(fsc);
534 
535 	ceph_destroy_client(fsc->client);
536 
537 	kfree(fsc);
538 	dout("destroy_fs_client %p done\n", fsc);
539 }
540 
541 /*
542  * caches
543  */
544 struct kmem_cache *ceph_inode_cachep;
545 struct kmem_cache *ceph_cap_cachep;
546 struct kmem_cache *ceph_dentry_cachep;
547 struct kmem_cache *ceph_file_cachep;
548 
549 static void ceph_inode_init_once(void *foo)
550 {
551 	struct ceph_inode_info *ci = foo;
552 	inode_init_once(&ci->vfs_inode);
553 }
554 
555 static int __init init_caches(void)
556 {
557 	ceph_inode_cachep = kmem_cache_create("ceph_inode_info",
558 				      sizeof(struct ceph_inode_info),
559 				      __alignof__(struct ceph_inode_info),
560 				      (SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD),
561 				      ceph_inode_init_once);
562 	if (ceph_inode_cachep == NULL)
563 		return -ENOMEM;
564 
565 	ceph_cap_cachep = KMEM_CACHE(ceph_cap,
566 				     SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD);
567 	if (ceph_cap_cachep == NULL)
568 		goto bad_cap;
569 
570 	ceph_dentry_cachep = KMEM_CACHE(ceph_dentry_info,
571 					SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD);
572 	if (ceph_dentry_cachep == NULL)
573 		goto bad_dentry;
574 
575 	ceph_file_cachep = KMEM_CACHE(ceph_file_info,
576 				      SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD);
577 	if (ceph_file_cachep == NULL)
578 		goto bad_file;
579 
580 	return 0;
581 
582 bad_file:
583 	kmem_cache_destroy(ceph_dentry_cachep);
584 bad_dentry:
585 	kmem_cache_destroy(ceph_cap_cachep);
586 bad_cap:
587 	kmem_cache_destroy(ceph_inode_cachep);
588 	return -ENOMEM;
589 }
590 
591 static void destroy_caches(void)
592 {
593 	kmem_cache_destroy(ceph_inode_cachep);
594 	kmem_cache_destroy(ceph_cap_cachep);
595 	kmem_cache_destroy(ceph_dentry_cachep);
596 	kmem_cache_destroy(ceph_file_cachep);
597 }
598 
599 
600 /*
601  * ceph_umount_begin - initiate forced umount.  Tear down down the
602  * mount, skipping steps that may hang while waiting for server(s).
603  */
604 static void ceph_umount_begin(struct super_block *sb)
605 {
606 	struct ceph_fs_client *fsc = ceph_sb_to_client(sb);
607 
608 	dout("ceph_umount_begin - starting forced umount\n");
609 	if (!fsc)
610 		return;
611 	fsc->mount_state = CEPH_MOUNT_SHUTDOWN;
612 	return;
613 }
614 
615 static const struct super_operations ceph_super_ops = {
616 	.alloc_inode	= ceph_alloc_inode,
617 	.destroy_inode	= ceph_destroy_inode,
618 	.write_inode    = ceph_write_inode,
619 	.sync_fs        = ceph_sync_fs,
620 	.put_super	= ceph_put_super,
621 	.show_options   = ceph_show_options,
622 	.statfs		= ceph_statfs,
623 	.umount_begin   = ceph_umount_begin,
624 };
625 
626 /*
627  * Bootstrap mount by opening the root directory.  Note the mount
628  * @started time from caller, and time out if this takes too long.
629  */
630 static struct dentry *open_root_dentry(struct ceph_fs_client *fsc,
631 				       const char *path,
632 				       unsigned long started)
633 {
634 	struct ceph_mds_client *mdsc = fsc->mdsc;
635 	struct ceph_mds_request *req = NULL;
636 	int err;
637 	struct dentry *root;
638 
639 	/* open dir */
640 	dout("open_root_inode opening '%s'\n", path);
641 	req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_GETATTR, USE_ANY_MDS);
642 	if (IS_ERR(req))
643 		return ERR_CAST(req);
644 	req->r_path1 = kstrdup(path, GFP_NOFS);
645 	req->r_ino1.ino = CEPH_INO_ROOT;
646 	req->r_ino1.snap = CEPH_NOSNAP;
647 	req->r_started = started;
648 	req->r_timeout = fsc->client->options->mount_timeout * HZ;
649 	req->r_args.getattr.mask = cpu_to_le32(CEPH_STAT_CAP_INODE);
650 	req->r_num_caps = 2;
651 	err = ceph_mdsc_do_request(mdsc, NULL, req);
652 	if (err == 0) {
653 		struct inode *inode = req->r_target_inode;
654 		req->r_target_inode = NULL;
655 		dout("open_root_inode success\n");
656 		if (ceph_ino(inode) == CEPH_INO_ROOT &&
657 		    fsc->sb->s_root == NULL) {
658 			root = d_make_root(inode);
659 			if (!root) {
660 				root = ERR_PTR(-ENOMEM);
661 				goto out;
662 			}
663 		} else {
664 			root = d_obtain_alias(inode);
665 		}
666 		ceph_init_dentry(root);
667 		dout("open_root_inode success, root dentry is %p\n", root);
668 	} else {
669 		root = ERR_PTR(err);
670 	}
671 out:
672 	ceph_mdsc_put_request(req);
673 	return root;
674 }
675 
676 
677 
678 
679 /*
680  * mount: join the ceph cluster, and open root directory.
681  */
682 static struct dentry *ceph_real_mount(struct ceph_fs_client *fsc,
683 		      const char *path)
684 {
685 	int err;
686 	unsigned long started = jiffies;  /* note the start time */
687 	struct dentry *root;
688 	int first = 0;   /* first vfsmount for this super_block */
689 
690 	dout("mount start\n");
691 	mutex_lock(&fsc->client->mount_mutex);
692 
693 	err = __ceph_open_session(fsc->client, started);
694 	if (err < 0)
695 		goto out;
696 
697 	dout("mount opening root\n");
698 	root = open_root_dentry(fsc, "", started);
699 	if (IS_ERR(root)) {
700 		err = PTR_ERR(root);
701 		goto out;
702 	}
703 	if (fsc->sb->s_root) {
704 		dput(root);
705 	} else {
706 		fsc->sb->s_root = root;
707 		first = 1;
708 
709 		err = ceph_fs_debugfs_init(fsc);
710 		if (err < 0)
711 			goto fail;
712 	}
713 
714 	if (path[0] == 0) {
715 		dget(root);
716 	} else {
717 		dout("mount opening base mountpoint\n");
718 		root = open_root_dentry(fsc, path, started);
719 		if (IS_ERR(root)) {
720 			err = PTR_ERR(root);
721 			goto fail;
722 		}
723 	}
724 
725 	fsc->mount_state = CEPH_MOUNT_MOUNTED;
726 	dout("mount success\n");
727 	mutex_unlock(&fsc->client->mount_mutex);
728 	return root;
729 
730 out:
731 	mutex_unlock(&fsc->client->mount_mutex);
732 	return ERR_PTR(err);
733 
734 fail:
735 	if (first) {
736 		dput(fsc->sb->s_root);
737 		fsc->sb->s_root = NULL;
738 	}
739 	goto out;
740 }
741 
742 static int ceph_set_super(struct super_block *s, void *data)
743 {
744 	struct ceph_fs_client *fsc = data;
745 	int ret;
746 
747 	dout("set_super %p data %p\n", s, data);
748 
749 	s->s_flags = fsc->mount_options->sb_flags;
750 	s->s_maxbytes = 1ULL << 40;  /* temp value until we get mdsmap */
751 
752 	s->s_fs_info = fsc;
753 	fsc->sb = s;
754 
755 	s->s_op = &ceph_super_ops;
756 	s->s_export_op = &ceph_export_ops;
757 
758 	s->s_time_gran = 1000;  /* 1000 ns == 1 us */
759 
760 	ret = set_anon_super(s, NULL);  /* what is that second arg for? */
761 	if (ret != 0)
762 		goto fail;
763 
764 	return ret;
765 
766 fail:
767 	s->s_fs_info = NULL;
768 	fsc->sb = NULL;
769 	return ret;
770 }
771 
772 /*
773  * share superblock if same fs AND options
774  */
775 static int ceph_compare_super(struct super_block *sb, void *data)
776 {
777 	struct ceph_fs_client *new = data;
778 	struct ceph_mount_options *fsopt = new->mount_options;
779 	struct ceph_options *opt = new->client->options;
780 	struct ceph_fs_client *other = ceph_sb_to_client(sb);
781 
782 	dout("ceph_compare_super %p\n", sb);
783 
784 	if (compare_mount_options(fsopt, opt, other)) {
785 		dout("monitor(s)/mount options don't match\n");
786 		return 0;
787 	}
788 	if ((opt->flags & CEPH_OPT_FSID) &&
789 	    ceph_fsid_compare(&opt->fsid, &other->client->fsid)) {
790 		dout("fsid doesn't match\n");
791 		return 0;
792 	}
793 	if (fsopt->sb_flags != other->mount_options->sb_flags) {
794 		dout("flags differ\n");
795 		return 0;
796 	}
797 	return 1;
798 }
799 
800 /*
801  * construct our own bdi so we can control readahead, etc.
802  */
803 static atomic_long_t bdi_seq = ATOMIC_LONG_INIT(0);
804 
805 static int ceph_register_bdi(struct super_block *sb,
806 			     struct ceph_fs_client *fsc)
807 {
808 	int err;
809 
810 	/* set ra_pages based on rasize mount option? */
811 	if (fsc->mount_options->rasize >= PAGE_CACHE_SIZE)
812 		fsc->backing_dev_info.ra_pages =
813 			(fsc->mount_options->rasize + PAGE_CACHE_SIZE - 1)
814 			>> PAGE_SHIFT;
815 	else
816 		fsc->backing_dev_info.ra_pages =
817 			default_backing_dev_info.ra_pages;
818 
819 	err = bdi_register(&fsc->backing_dev_info, NULL, "ceph-%d",
820 			   atomic_long_inc_return(&bdi_seq));
821 	if (!err)
822 		sb->s_bdi = &fsc->backing_dev_info;
823 	return err;
824 }
825 
826 static struct dentry *ceph_mount(struct file_system_type *fs_type,
827 		       int flags, const char *dev_name, void *data)
828 {
829 	struct super_block *sb;
830 	struct ceph_fs_client *fsc;
831 	struct dentry *res;
832 	int err;
833 	int (*compare_super)(struct super_block *, void *) = ceph_compare_super;
834 	const char *path = NULL;
835 	struct ceph_mount_options *fsopt = NULL;
836 	struct ceph_options *opt = NULL;
837 
838 	dout("ceph_mount\n");
839 	err = parse_mount_options(&fsopt, &opt, flags, data, dev_name, &path);
840 	if (err < 0) {
841 		res = ERR_PTR(err);
842 		goto out_final;
843 	}
844 
845 	/* create client (which we may/may not use) */
846 	fsc = create_fs_client(fsopt, opt);
847 	if (IS_ERR(fsc)) {
848 		res = ERR_CAST(fsc);
849 		destroy_mount_options(fsopt);
850 		ceph_destroy_options(opt);
851 		goto out_final;
852 	}
853 
854 	err = ceph_mdsc_init(fsc);
855 	if (err < 0) {
856 		res = ERR_PTR(err);
857 		goto out;
858 	}
859 
860 	if (ceph_test_opt(fsc->client, NOSHARE))
861 		compare_super = NULL;
862 	sb = sget(fs_type, compare_super, ceph_set_super, fsc);
863 	if (IS_ERR(sb)) {
864 		res = ERR_CAST(sb);
865 		goto out;
866 	}
867 
868 	if (ceph_sb_to_client(sb) != fsc) {
869 		ceph_mdsc_destroy(fsc);
870 		destroy_fs_client(fsc);
871 		fsc = ceph_sb_to_client(sb);
872 		dout("get_sb got existing client %p\n", fsc);
873 	} else {
874 		dout("get_sb using new client %p\n", fsc);
875 		err = ceph_register_bdi(sb, fsc);
876 		if (err < 0) {
877 			res = ERR_PTR(err);
878 			goto out_splat;
879 		}
880 	}
881 
882 	res = ceph_real_mount(fsc, path);
883 	if (IS_ERR(res))
884 		goto out_splat;
885 	dout("root %p inode %p ino %llx.%llx\n", res,
886 	     res->d_inode, ceph_vinop(res->d_inode));
887 	return res;
888 
889 out_splat:
890 	ceph_mdsc_close_sessions(fsc->mdsc);
891 	deactivate_locked_super(sb);
892 	goto out_final;
893 
894 out:
895 	ceph_mdsc_destroy(fsc);
896 	destroy_fs_client(fsc);
897 out_final:
898 	dout("ceph_mount fail %ld\n", PTR_ERR(res));
899 	return res;
900 }
901 
902 static void ceph_kill_sb(struct super_block *s)
903 {
904 	struct ceph_fs_client *fsc = ceph_sb_to_client(s);
905 	dout("kill_sb %p\n", s);
906 	ceph_mdsc_pre_umount(fsc->mdsc);
907 	kill_anon_super(s);    /* will call put_super after sb is r/o */
908 	ceph_mdsc_destroy(fsc);
909 	destroy_fs_client(fsc);
910 }
911 
912 static struct file_system_type ceph_fs_type = {
913 	.owner		= THIS_MODULE,
914 	.name		= "ceph",
915 	.mount		= ceph_mount,
916 	.kill_sb	= ceph_kill_sb,
917 	.fs_flags	= FS_RENAME_DOES_D_MOVE,
918 };
919 
920 #define _STRINGIFY(x) #x
921 #define STRINGIFY(x) _STRINGIFY(x)
922 
923 static int __init init_ceph(void)
924 {
925 	int ret = init_caches();
926 	if (ret)
927 		goto out;
928 
929 	ret = register_filesystem(&ceph_fs_type);
930 	if (ret)
931 		goto out_icache;
932 
933 	pr_info("loaded (mds proto %d)\n", CEPH_MDSC_PROTOCOL);
934 
935 	return 0;
936 
937 out_icache:
938 	destroy_caches();
939 out:
940 	return ret;
941 }
942 
943 static void __exit exit_ceph(void)
944 {
945 	dout("exit_ceph\n");
946 	unregister_filesystem(&ceph_fs_type);
947 	destroy_caches();
948 }
949 
950 module_init(init_ceph);
951 module_exit(exit_ceph);
952 
953 MODULE_AUTHOR("Sage Weil <sage@newdream.net>");
954 MODULE_AUTHOR("Yehuda Sadeh <yehuda@hq.newdream.net>");
955 MODULE_AUTHOR("Patience Warnick <patience@newdream.net>");
956 MODULE_DESCRIPTION("Ceph filesystem for Linux");
957 MODULE_LICENSE("GPL");
958