xref: /linux/fs/smb/client/cached_dir.c (revision 0235da0faeeec1c1ce2265fc627f5d5d9cae7ce8)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  *  Functions to handle the cached directory entries
4  *
5  *  Copyright (c) 2022, Ronnie Sahlberg <lsahlber@redhat.com>
6  */
7 
8 #include <linux/namei.h>
9 #include "cifsglob.h"
10 #include "cifsproto.h"
11 #include "cifs_debug.h"
12 #include "smb2proto.h"
13 #include "cached_dir.h"
14 
15 static struct cached_fid *init_cached_dir(const char *path);
16 static void free_cached_dir(struct cached_fid *cfid);
17 static void smb2_close_cached_fid(struct kref *ref);
18 static void cfids_laundromat_worker(struct work_struct *work);
19 
20 struct cached_dir_dentry {
21 	struct list_head entry;
22 	struct dentry *dentry;
23 };
24 
find_or_create_cached_dir(struct cached_fids * cfids,const char * path,bool lookup_only,__u32 max_cached_dirs)25 static struct cached_fid *find_or_create_cached_dir(struct cached_fids *cfids,
26 						    const char *path,
27 						    bool lookup_only,
28 						    __u32 max_cached_dirs)
29 {
30 	struct cached_fid *cfid;
31 
32 	spin_lock(&cfids->cfid_list_lock);
33 	list_for_each_entry(cfid, &cfids->entries, entry) {
34 		if (!strcmp(cfid->path, path)) {
35 			/*
36 			 * If it doesn't have a lease it is either not yet
37 			 * fully cached or it may be in the process of
38 			 * being deleted due to a lease break.
39 			 */
40 			if (!cfid->time || !cfid->has_lease) {
41 				spin_unlock(&cfids->cfid_list_lock);
42 				return NULL;
43 			}
44 			kref_get(&cfid->refcount);
45 			spin_unlock(&cfids->cfid_list_lock);
46 			return cfid;
47 		}
48 	}
49 	if (lookup_only) {
50 		spin_unlock(&cfids->cfid_list_lock);
51 		return NULL;
52 	}
53 	if (cfids->num_entries >= max_cached_dirs) {
54 		spin_unlock(&cfids->cfid_list_lock);
55 		return NULL;
56 	}
57 	cfid = init_cached_dir(path);
58 	if (cfid == NULL) {
59 		spin_unlock(&cfids->cfid_list_lock);
60 		return NULL;
61 	}
62 	cfid->cfids = cfids;
63 	cfids->num_entries++;
64 	list_add(&cfid->entry, &cfids->entries);
65 	cfid->on_list = true;
66 	kref_get(&cfid->refcount);
67 	/*
68 	 * Set @cfid->has_lease to true during construction so that the lease
69 	 * reference can be put in cached_dir_lease_break() due to a potential
70 	 * lease break right after the request is sent or while @cfid is still
71 	 * being cached, or if a reconnection is triggered during construction.
72 	 * Concurrent processes won't be to use it yet due to @cfid->time being
73 	 * zero.
74 	 */
75 	cfid->has_lease = true;
76 
77 	spin_unlock(&cfids->cfid_list_lock);
78 	return cfid;
79 }
80 
81 static struct dentry *
path_to_dentry(struct cifs_sb_info * cifs_sb,const char * path)82 path_to_dentry(struct cifs_sb_info *cifs_sb, const char *path)
83 {
84 	struct dentry *dentry;
85 	const char *s, *p;
86 	char sep;
87 
88 	sep = CIFS_DIR_SEP(cifs_sb);
89 	dentry = dget(cifs_sb->root);
90 	s = path;
91 
92 	do {
93 		struct inode *dir = d_inode(dentry);
94 		struct dentry *child;
95 
96 		if (!S_ISDIR(dir->i_mode)) {
97 			dput(dentry);
98 			dentry = ERR_PTR(-ENOTDIR);
99 			break;
100 		}
101 
102 		/* skip separators */
103 		while (*s == sep)
104 			s++;
105 		if (!*s)
106 			break;
107 		p = s++;
108 		/* next separator */
109 		while (*s && *s != sep)
110 			s++;
111 
112 		child = lookup_positive_unlocked(p, dentry, s - p);
113 		dput(dentry);
114 		dentry = child;
115 	} while (!IS_ERR(dentry));
116 	return dentry;
117 }
118 
path_no_prefix(struct cifs_sb_info * cifs_sb,const char * path)119 static const char *path_no_prefix(struct cifs_sb_info *cifs_sb,
120 				  const char *path)
121 {
122 	size_t len = 0;
123 
124 	if (!*path)
125 		return path;
126 
127 	if ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_USE_PREFIX_PATH) &&
128 	    cifs_sb->prepath) {
129 		len = strlen(cifs_sb->prepath) + 1;
130 		if (unlikely(len > strlen(path)))
131 			return ERR_PTR(-EINVAL);
132 	}
133 	return path + len;
134 }
135 
136 /*
137  * Open the and cache a directory handle.
138  * If error then *cfid is not initialized.
139  */
open_cached_dir(unsigned int xid,struct cifs_tcon * tcon,const char * path,struct cifs_sb_info * cifs_sb,bool lookup_only,struct cached_fid ** ret_cfid)140 int open_cached_dir(unsigned int xid, struct cifs_tcon *tcon,
141 		    const char *path,
142 		    struct cifs_sb_info *cifs_sb,
143 		    bool lookup_only, struct cached_fid **ret_cfid)
144 {
145 	struct cifs_ses *ses;
146 	struct TCP_Server_Info *server;
147 	struct cifs_open_parms oparms;
148 	struct smb2_create_rsp *o_rsp = NULL;
149 	struct smb2_query_info_rsp *qi_rsp = NULL;
150 	int resp_buftype[2];
151 	struct smb_rqst rqst[2];
152 	struct kvec rsp_iov[2];
153 	struct kvec open_iov[SMB2_CREATE_IOV_SIZE];
154 	struct kvec qi_iov[1];
155 	int rc, flags = 0;
156 	__le16 *utf16_path = NULL;
157 	u8 oplock = SMB2_OPLOCK_LEVEL_II;
158 	struct cifs_fid *pfid;
159 	struct dentry *dentry = NULL;
160 	struct cached_fid *cfid;
161 	struct cached_fids *cfids;
162 	const char *npath;
163 	int retries = 0, cur_sleep = 1;
164 
165 	if (cifs_sb->root == NULL)
166 		return -ENOENT;
167 
168 	if (tcon == NULL)
169 		return -EOPNOTSUPP;
170 
171 	ses = tcon->ses;
172 	cfids = tcon->cfids;
173 
174 	if (cfids == NULL)
175 		return -EOPNOTSUPP;
176 
177 replay_again:
178 	/* reinitialize for possible replay */
179 	flags = 0;
180 	oplock = SMB2_OPLOCK_LEVEL_II;
181 	server = cifs_pick_channel(ses);
182 
183 	if (!server->ops->new_lease_key)
184 		return -EIO;
185 
186 	utf16_path = cifs_convert_path_to_utf16(path, cifs_sb);
187 	if (!utf16_path)
188 		return -ENOMEM;
189 
190 	cfid = find_or_create_cached_dir(cfids, path, lookup_only, tcon->max_cached_dirs);
191 	if (cfid == NULL) {
192 		kfree(utf16_path);
193 		return -ENOENT;
194 	}
195 	/*
196 	 * Return cached fid if it is valid (has a lease and has a time).
197 	 * Otherwise, it is either a new entry or laundromat worker removed it
198 	 * from @cfids->entries.  Caller will put last reference if the latter.
199 	 */
200 	spin_lock(&cfids->cfid_list_lock);
201 	if (cfid->has_lease && cfid->time) {
202 		spin_unlock(&cfids->cfid_list_lock);
203 		*ret_cfid = cfid;
204 		kfree(utf16_path);
205 		return 0;
206 	}
207 	spin_unlock(&cfids->cfid_list_lock);
208 
209 	/*
210 	 * Skip any prefix paths in @path as lookup_positive_unlocked() ends up
211 	 * calling ->lookup() which already adds those through
212 	 * build_path_from_dentry().  Also, do it earlier as we might reconnect
213 	 * below when trying to send compounded request and then potentially
214 	 * having a different prefix path (e.g. after DFS failover).
215 	 */
216 	npath = path_no_prefix(cifs_sb, path);
217 	if (IS_ERR(npath)) {
218 		rc = PTR_ERR(npath);
219 		goto out;
220 	}
221 
222 	if (!npath[0]) {
223 		dentry = dget(cifs_sb->root);
224 	} else {
225 		dentry = path_to_dentry(cifs_sb, npath);
226 		if (IS_ERR(dentry)) {
227 			rc = -ENOENT;
228 			goto out;
229 		}
230 	}
231 	cfid->dentry = dentry;
232 	cfid->tcon = tcon;
233 
234 	/*
235 	 * We do not hold the lock for the open because in case
236 	 * SMB2_open needs to reconnect.
237 	 * This is safe because no other thread will be able to get a ref
238 	 * to the cfid until we have finished opening the file and (possibly)
239 	 * acquired a lease.
240 	 */
241 	if (smb3_encryption_required(tcon))
242 		flags |= CIFS_TRANSFORM_REQ;
243 
244 	pfid = &cfid->fid;
245 	server->ops->new_lease_key(pfid);
246 
247 	memset(rqst, 0, sizeof(rqst));
248 	resp_buftype[0] = resp_buftype[1] = CIFS_NO_BUFFER;
249 	memset(rsp_iov, 0, sizeof(rsp_iov));
250 
251 	/* Open */
252 	memset(&open_iov, 0, sizeof(open_iov));
253 	rqst[0].rq_iov = open_iov;
254 	rqst[0].rq_nvec = SMB2_CREATE_IOV_SIZE;
255 
256 	oparms = (struct cifs_open_parms) {
257 		.tcon = tcon,
258 		.path = path,
259 		.create_options = cifs_create_options(cifs_sb, CREATE_NOT_FILE),
260 		.desired_access =  FILE_READ_DATA | FILE_READ_ATTRIBUTES |
261 				   FILE_READ_EA,
262 		.disposition = FILE_OPEN,
263 		.fid = pfid,
264 		.replay = !!(retries),
265 	};
266 
267 	rc = SMB2_open_init(tcon, server,
268 			    &rqst[0], &oplock, &oparms, utf16_path);
269 	if (rc)
270 		goto oshr_free;
271 	smb2_set_next_command(tcon, &rqst[0]);
272 
273 	memset(&qi_iov, 0, sizeof(qi_iov));
274 	rqst[1].rq_iov = qi_iov;
275 	rqst[1].rq_nvec = 1;
276 
277 	rc = SMB2_query_info_init(tcon, server,
278 				  &rqst[1], COMPOUND_FID,
279 				  COMPOUND_FID, FILE_ALL_INFORMATION,
280 				  SMB2_O_INFO_FILE, 0,
281 				  sizeof(struct smb2_file_all_info) +
282 				  PATH_MAX * 2, 0, NULL);
283 	if (rc)
284 		goto oshr_free;
285 
286 	smb2_set_related(&rqst[1]);
287 
288 	if (retries) {
289 		smb2_set_replay(server, &rqst[0]);
290 		smb2_set_replay(server, &rqst[1]);
291 	}
292 
293 	rc = compound_send_recv(xid, ses, server,
294 				flags, 2, rqst,
295 				resp_buftype, rsp_iov);
296 	if (rc) {
297 		if (rc == -EREMCHG) {
298 			tcon->need_reconnect = true;
299 			pr_warn_once("server share %s deleted\n",
300 				     tcon->tree_name);
301 		}
302 		goto oshr_free;
303 	}
304 	cfid->is_open = true;
305 
306 	spin_lock(&cfids->cfid_list_lock);
307 
308 	o_rsp = (struct smb2_create_rsp *)rsp_iov[0].iov_base;
309 	oparms.fid->persistent_fid = o_rsp->PersistentFileId;
310 	oparms.fid->volatile_fid = o_rsp->VolatileFileId;
311 #ifdef CONFIG_CIFS_DEBUG2
312 	oparms.fid->mid = le64_to_cpu(o_rsp->hdr.MessageId);
313 #endif /* CIFS_DEBUG2 */
314 
315 
316 	if (o_rsp->OplockLevel != SMB2_OPLOCK_LEVEL_LEASE) {
317 		spin_unlock(&cfids->cfid_list_lock);
318 		rc = -EINVAL;
319 		goto oshr_free;
320 	}
321 
322 	rc = smb2_parse_contexts(server, rsp_iov,
323 				 &oparms.fid->epoch,
324 				 oparms.fid->lease_key,
325 				 &oplock, NULL, NULL);
326 	if (rc) {
327 		spin_unlock(&cfids->cfid_list_lock);
328 		goto oshr_free;
329 	}
330 
331 	rc = -EINVAL;
332 	if (!(oplock & SMB2_LEASE_READ_CACHING_HE)) {
333 		spin_unlock(&cfids->cfid_list_lock);
334 		goto oshr_free;
335 	}
336 	qi_rsp = (struct smb2_query_info_rsp *)rsp_iov[1].iov_base;
337 	if (le32_to_cpu(qi_rsp->OutputBufferLength) < sizeof(struct smb2_file_all_info)) {
338 		spin_unlock(&cfids->cfid_list_lock);
339 		goto oshr_free;
340 	}
341 	if (!smb2_validate_and_copy_iov(
342 				le16_to_cpu(qi_rsp->OutputBufferOffset),
343 				sizeof(struct smb2_file_all_info),
344 				&rsp_iov[1], sizeof(struct smb2_file_all_info),
345 				(char *)&cfid->file_all_info))
346 		cfid->file_all_info_is_valid = true;
347 
348 	cfid->time = jiffies;
349 	spin_unlock(&cfids->cfid_list_lock);
350 	/* At this point the directory handle is fully cached */
351 	rc = 0;
352 
353 oshr_free:
354 	SMB2_open_free(&rqst[0]);
355 	SMB2_query_info_free(&rqst[1]);
356 	free_rsp_buf(resp_buftype[0], rsp_iov[0].iov_base);
357 	free_rsp_buf(resp_buftype[1], rsp_iov[1].iov_base);
358 out:
359 	if (rc) {
360 		spin_lock(&cfids->cfid_list_lock);
361 		if (cfid->on_list) {
362 			list_del(&cfid->entry);
363 			cfid->on_list = false;
364 			cfids->num_entries--;
365 		}
366 		if (cfid->has_lease) {
367 			/*
368 			 * We are guaranteed to have two references at this
369 			 * point. One for the caller and one for a potential
370 			 * lease. Release one here, and the second below.
371 			 */
372 			cfid->has_lease = false;
373 			kref_put(&cfid->refcount, smb2_close_cached_fid);
374 		}
375 		spin_unlock(&cfids->cfid_list_lock);
376 
377 		kref_put(&cfid->refcount, smb2_close_cached_fid);
378 	} else {
379 		*ret_cfid = cfid;
380 		atomic_inc(&tcon->num_remote_opens);
381 	}
382 	kfree(utf16_path);
383 
384 	if (is_replayable_error(rc) &&
385 	    smb2_should_replay(tcon, &retries, &cur_sleep))
386 		goto replay_again;
387 
388 	return rc;
389 }
390 
open_cached_dir_by_dentry(struct cifs_tcon * tcon,struct dentry * dentry,struct cached_fid ** ret_cfid)391 int open_cached_dir_by_dentry(struct cifs_tcon *tcon,
392 			      struct dentry *dentry,
393 			      struct cached_fid **ret_cfid)
394 {
395 	struct cached_fid *cfid;
396 	struct cached_fids *cfids = tcon->cfids;
397 
398 	if (cfids == NULL)
399 		return -EOPNOTSUPP;
400 
401 	spin_lock(&cfids->cfid_list_lock);
402 	list_for_each_entry(cfid, &cfids->entries, entry) {
403 		if (dentry && cfid->dentry == dentry) {
404 			cifs_dbg(FYI, "found a cached file handle by dentry\n");
405 			kref_get(&cfid->refcount);
406 			*ret_cfid = cfid;
407 			spin_unlock(&cfids->cfid_list_lock);
408 			return 0;
409 		}
410 	}
411 	spin_unlock(&cfids->cfid_list_lock);
412 	return -ENOENT;
413 }
414 
415 static void
smb2_close_cached_fid(struct kref * ref)416 smb2_close_cached_fid(struct kref *ref)
417 {
418 	struct cached_fid *cfid = container_of(ref, struct cached_fid,
419 					       refcount);
420 	int rc;
421 
422 	spin_lock(&cfid->cfids->cfid_list_lock);
423 	if (cfid->on_list) {
424 		list_del(&cfid->entry);
425 		cfid->on_list = false;
426 		cfid->cfids->num_entries--;
427 	}
428 	spin_unlock(&cfid->cfids->cfid_list_lock);
429 
430 	dput(cfid->dentry);
431 	cfid->dentry = NULL;
432 
433 	if (cfid->is_open) {
434 		rc = SMB2_close(0, cfid->tcon, cfid->fid.persistent_fid,
435 			   cfid->fid.volatile_fid);
436 		if (rc) /* should we retry on -EBUSY or -EAGAIN? */
437 			cifs_dbg(VFS, "close cached dir rc %d\n", rc);
438 	}
439 
440 	free_cached_dir(cfid);
441 }
442 
drop_cached_dir_by_name(const unsigned int xid,struct cifs_tcon * tcon,const char * name,struct cifs_sb_info * cifs_sb)443 void drop_cached_dir_by_name(const unsigned int xid, struct cifs_tcon *tcon,
444 			     const char *name, struct cifs_sb_info *cifs_sb)
445 {
446 	struct cached_fid *cfid = NULL;
447 	int rc;
448 
449 	rc = open_cached_dir(xid, tcon, name, cifs_sb, true, &cfid);
450 	if (rc) {
451 		cifs_dbg(FYI, "no cached dir found for rmdir(%s)\n", name);
452 		return;
453 	}
454 	spin_lock(&cfid->cfids->cfid_list_lock);
455 	if (cfid->has_lease) {
456 		cfid->has_lease = false;
457 		kref_put(&cfid->refcount, smb2_close_cached_fid);
458 	}
459 	spin_unlock(&cfid->cfids->cfid_list_lock);
460 	close_cached_dir(cfid);
461 }
462 
463 
close_cached_dir(struct cached_fid * cfid)464 void close_cached_dir(struct cached_fid *cfid)
465 {
466 	kref_put(&cfid->refcount, smb2_close_cached_fid);
467 }
468 
469 /*
470  * Called from cifs_kill_sb when we unmount a share
471  */
close_all_cached_dirs(struct cifs_sb_info * cifs_sb)472 void close_all_cached_dirs(struct cifs_sb_info *cifs_sb)
473 {
474 	struct rb_root *root = &cifs_sb->tlink_tree;
475 	struct rb_node *node;
476 	struct cached_fid *cfid;
477 	struct cifs_tcon *tcon;
478 	struct tcon_link *tlink;
479 	struct cached_fids *cfids;
480 	struct cached_dir_dentry *tmp_list, *q;
481 	LIST_HEAD(entry);
482 
483 	spin_lock(&cifs_sb->tlink_tree_lock);
484 	for (node = rb_first(root); node; node = rb_next(node)) {
485 		tlink = rb_entry(node, struct tcon_link, tl_rbnode);
486 		tcon = tlink_tcon(tlink);
487 		if (IS_ERR(tcon))
488 			continue;
489 		cfids = tcon->cfids;
490 		if (cfids == NULL)
491 			continue;
492 		spin_lock(&cfids->cfid_list_lock);
493 		list_for_each_entry(cfid, &cfids->entries, entry) {
494 			tmp_list = kmalloc(sizeof(*tmp_list), GFP_ATOMIC);
495 			if (tmp_list == NULL)
496 				break;
497 			spin_lock(&cfid->fid_lock);
498 			tmp_list->dentry = cfid->dentry;
499 			cfid->dentry = NULL;
500 			spin_unlock(&cfid->fid_lock);
501 
502 			list_add_tail(&tmp_list->entry, &entry);
503 		}
504 		spin_unlock(&cfids->cfid_list_lock);
505 	}
506 	spin_unlock(&cifs_sb->tlink_tree_lock);
507 
508 	list_for_each_entry_safe(tmp_list, q, &entry, entry) {
509 		list_del(&tmp_list->entry);
510 		dput(tmp_list->dentry);
511 		kfree(tmp_list);
512 	}
513 
514 	/* Flush any pending work that will drop dentries */
515 	flush_workqueue(cfid_put_wq);
516 }
517 
518 /*
519  * Invalidate all cached dirs when a TCON has been reset
520  * due to a session loss.
521  */
invalidate_all_cached_dirs(struct cifs_tcon * tcon)522 void invalidate_all_cached_dirs(struct cifs_tcon *tcon)
523 {
524 	struct cached_fids *cfids = tcon->cfids;
525 	struct cached_fid *cfid, *q;
526 
527 	if (cfids == NULL)
528 		return;
529 
530 	/*
531 	 * Mark all the cfids as closed, and move them to the cfids->dying list.
532 	 * They'll be cleaned up later by cfids_invalidation_worker. Take
533 	 * a reference to each cfid during this process.
534 	 */
535 	spin_lock(&cfids->cfid_list_lock);
536 	list_for_each_entry_safe(cfid, q, &cfids->entries, entry) {
537 		list_move(&cfid->entry, &cfids->dying);
538 		cfids->num_entries--;
539 		cfid->is_open = false;
540 		cfid->on_list = false;
541 		if (cfid->has_lease) {
542 			/*
543 			 * The lease was never cancelled from the server,
544 			 * so steal that reference.
545 			 */
546 			cfid->has_lease = false;
547 		} else
548 			kref_get(&cfid->refcount);
549 	}
550 	/*
551 	 * Queue dropping of the dentries once locks have been dropped
552 	 */
553 	if (!list_empty(&cfids->dying))
554 		queue_work(cfid_put_wq, &cfids->invalidation_work);
555 	spin_unlock(&cfids->cfid_list_lock);
556 }
557 
558 static void
cached_dir_offload_close(struct work_struct * work)559 cached_dir_offload_close(struct work_struct *work)
560 {
561 	struct cached_fid *cfid = container_of(work,
562 				struct cached_fid, close_work);
563 	struct cifs_tcon *tcon = cfid->tcon;
564 
565 	WARN_ON(cfid->on_list);
566 
567 	kref_put(&cfid->refcount, smb2_close_cached_fid);
568 	cifs_put_tcon(tcon, netfs_trace_tcon_ref_put_cached_close);
569 }
570 
571 /*
572  * Release the cached directory's dentry, and then queue work to drop cached
573  * directory itself (closing on server if needed).
574  *
575  * Must be called with a reference to the cached_fid and a reference to the
576  * tcon.
577  */
cached_dir_put_work(struct work_struct * work)578 static void cached_dir_put_work(struct work_struct *work)
579 {
580 	struct cached_fid *cfid = container_of(work, struct cached_fid,
581 					       put_work);
582 	struct dentry *dentry;
583 
584 	spin_lock(&cfid->fid_lock);
585 	dentry = cfid->dentry;
586 	cfid->dentry = NULL;
587 	spin_unlock(&cfid->fid_lock);
588 
589 	dput(dentry);
590 	queue_work(serverclose_wq, &cfid->close_work);
591 }
592 
cached_dir_lease_break(struct cifs_tcon * tcon,__u8 lease_key[16])593 int cached_dir_lease_break(struct cifs_tcon *tcon, __u8 lease_key[16])
594 {
595 	struct cached_fids *cfids = tcon->cfids;
596 	struct cached_fid *cfid;
597 
598 	if (cfids == NULL)
599 		return false;
600 
601 	spin_lock(&cfids->cfid_list_lock);
602 	list_for_each_entry(cfid, &cfids->entries, entry) {
603 		if (cfid->has_lease &&
604 		    !memcmp(lease_key,
605 			    cfid->fid.lease_key,
606 			    SMB2_LEASE_KEY_SIZE)) {
607 			cfid->has_lease = false;
608 			cfid->time = 0;
609 			/*
610 			 * We found a lease remove it from the list
611 			 * so no threads can access it.
612 			 */
613 			list_del(&cfid->entry);
614 			cfid->on_list = false;
615 			cfids->num_entries--;
616 
617 			++tcon->tc_count;
618 			trace_smb3_tcon_ref(tcon->debug_id, tcon->tc_count,
619 					    netfs_trace_tcon_ref_get_cached_lease_break);
620 			queue_work(cfid_put_wq, &cfid->put_work);
621 			spin_unlock(&cfids->cfid_list_lock);
622 			return true;
623 		}
624 	}
625 	spin_unlock(&cfids->cfid_list_lock);
626 	return false;
627 }
628 
init_cached_dir(const char * path)629 static struct cached_fid *init_cached_dir(const char *path)
630 {
631 	struct cached_fid *cfid;
632 
633 	cfid = kzalloc(sizeof(*cfid), GFP_ATOMIC);
634 	if (!cfid)
635 		return NULL;
636 	cfid->path = kstrdup(path, GFP_ATOMIC);
637 	if (!cfid->path) {
638 		kfree(cfid);
639 		return NULL;
640 	}
641 
642 	INIT_WORK(&cfid->close_work, cached_dir_offload_close);
643 	INIT_WORK(&cfid->put_work, cached_dir_put_work);
644 	INIT_LIST_HEAD(&cfid->entry);
645 	INIT_LIST_HEAD(&cfid->dirents.entries);
646 	mutex_init(&cfid->dirents.de_mutex);
647 	spin_lock_init(&cfid->fid_lock);
648 	kref_init(&cfid->refcount);
649 	return cfid;
650 }
651 
free_cached_dir(struct cached_fid * cfid)652 static void free_cached_dir(struct cached_fid *cfid)
653 {
654 	struct cached_dirent *dirent, *q;
655 
656 	WARN_ON(work_pending(&cfid->close_work));
657 	WARN_ON(work_pending(&cfid->put_work));
658 
659 	dput(cfid->dentry);
660 	cfid->dentry = NULL;
661 
662 	/*
663 	 * Delete all cached dirent names
664 	 */
665 	list_for_each_entry_safe(dirent, q, &cfid->dirents.entries, entry) {
666 		list_del(&dirent->entry);
667 		kfree(dirent->name);
668 		kfree(dirent);
669 	}
670 
671 	kfree(cfid->path);
672 	cfid->path = NULL;
673 	kfree(cfid);
674 }
675 
cfids_invalidation_worker(struct work_struct * work)676 static void cfids_invalidation_worker(struct work_struct *work)
677 {
678 	struct cached_fids *cfids = container_of(work, struct cached_fids,
679 						 invalidation_work);
680 	struct cached_fid *cfid, *q;
681 	LIST_HEAD(entry);
682 
683 	spin_lock(&cfids->cfid_list_lock);
684 	/* move cfids->dying to the local list */
685 	list_cut_before(&entry, &cfids->dying, &cfids->dying);
686 	spin_unlock(&cfids->cfid_list_lock);
687 
688 	list_for_each_entry_safe(cfid, q, &entry, entry) {
689 		list_del(&cfid->entry);
690 		/* Drop the ref-count acquired in invalidate_all_cached_dirs */
691 		kref_put(&cfid->refcount, smb2_close_cached_fid);
692 	}
693 }
694 
cfids_laundromat_worker(struct work_struct * work)695 static void cfids_laundromat_worker(struct work_struct *work)
696 {
697 	struct cached_fids *cfids;
698 	struct cached_fid *cfid, *q;
699 	struct dentry *dentry;
700 	LIST_HEAD(entry);
701 
702 	cfids = container_of(work, struct cached_fids, laundromat_work.work);
703 
704 	spin_lock(&cfids->cfid_list_lock);
705 	list_for_each_entry_safe(cfid, q, &cfids->entries, entry) {
706 		if (cfid->time &&
707 		    time_after(jiffies, cfid->time + HZ * dir_cache_timeout)) {
708 			cfid->on_list = false;
709 			list_move(&cfid->entry, &entry);
710 			cfids->num_entries--;
711 			if (cfid->has_lease) {
712 				/*
713 				 * Our lease has not yet been cancelled from the
714 				 * server. Steal that reference.
715 				 */
716 				cfid->has_lease = false;
717 			} else
718 				kref_get(&cfid->refcount);
719 		}
720 	}
721 	spin_unlock(&cfids->cfid_list_lock);
722 
723 	list_for_each_entry_safe(cfid, q, &entry, entry) {
724 		list_del(&cfid->entry);
725 
726 		spin_lock(&cfid->fid_lock);
727 		dentry = cfid->dentry;
728 		cfid->dentry = NULL;
729 		spin_unlock(&cfid->fid_lock);
730 
731 		dput(dentry);
732 		if (cfid->is_open) {
733 			spin_lock(&cifs_tcp_ses_lock);
734 			++cfid->tcon->tc_count;
735 			trace_smb3_tcon_ref(cfid->tcon->debug_id, cfid->tcon->tc_count,
736 					    netfs_trace_tcon_ref_get_cached_laundromat);
737 			spin_unlock(&cifs_tcp_ses_lock);
738 			queue_work(serverclose_wq, &cfid->close_work);
739 		} else
740 			/*
741 			 * Drop the ref-count from above, either the lease-ref (if there
742 			 * was one) or the extra one acquired.
743 			 */
744 			kref_put(&cfid->refcount, smb2_close_cached_fid);
745 	}
746 	queue_delayed_work(cfid_put_wq, &cfids->laundromat_work,
747 			   dir_cache_timeout * HZ);
748 }
749 
init_cached_dirs(void)750 struct cached_fids *init_cached_dirs(void)
751 {
752 	struct cached_fids *cfids;
753 
754 	cfids = kzalloc(sizeof(*cfids), GFP_KERNEL);
755 	if (!cfids)
756 		return NULL;
757 	spin_lock_init(&cfids->cfid_list_lock);
758 	INIT_LIST_HEAD(&cfids->entries);
759 	INIT_LIST_HEAD(&cfids->dying);
760 
761 	INIT_WORK(&cfids->invalidation_work, cfids_invalidation_worker);
762 	INIT_DELAYED_WORK(&cfids->laundromat_work, cfids_laundromat_worker);
763 	queue_delayed_work(cfid_put_wq, &cfids->laundromat_work,
764 			   dir_cache_timeout * HZ);
765 
766 	return cfids;
767 }
768 
769 /*
770  * Called from tconInfoFree when we are tearing down the tcon.
771  * There are no active users or open files/directories at this point.
772  */
free_cached_dirs(struct cached_fids * cfids)773 void free_cached_dirs(struct cached_fids *cfids)
774 {
775 	struct cached_fid *cfid, *q;
776 	LIST_HEAD(entry);
777 
778 	if (cfids == NULL)
779 		return;
780 
781 	cancel_delayed_work_sync(&cfids->laundromat_work);
782 	cancel_work_sync(&cfids->invalidation_work);
783 
784 	spin_lock(&cfids->cfid_list_lock);
785 	list_for_each_entry_safe(cfid, q, &cfids->entries, entry) {
786 		cfid->on_list = false;
787 		cfid->is_open = false;
788 		list_move(&cfid->entry, &entry);
789 	}
790 	list_for_each_entry_safe(cfid, q, &cfids->dying, entry) {
791 		cfid->on_list = false;
792 		cfid->is_open = false;
793 		list_move(&cfid->entry, &entry);
794 	}
795 	spin_unlock(&cfids->cfid_list_lock);
796 
797 	list_for_each_entry_safe(cfid, q, &entry, entry) {
798 		list_del(&cfid->entry);
799 		free_cached_dir(cfid);
800 	}
801 
802 	kfree(cfids);
803 }
804