summaryrefslogtreecommitdiff
path: root/fs/cifs/cached_dir.c
blob: 753b850b6f87878721ff5f2689464f829168477c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
// SPDX-License-Identifier: GPL-2.0
/*
 *  Functions to handle the cached directory entries
 *
 *  Copyright (c) 2022, Ronnie Sahlberg <lsahlber@redhat.com>
 */

#include "cifsglob.h"
#include "cifsproto.h"
#include "cifs_debug.h"
#include "smb2proto.h"
#include "cached_dir.h"

/*
 * Open the and cache a directory handle.
 * If error then *cfid is not initialized.
 */
int open_cached_dir(unsigned int xid, struct cifs_tcon *tcon,
		const char *path,
		struct cifs_sb_info *cifs_sb,
		struct cached_fid **cfid)
{
	struct cifs_ses *ses;
	struct TCP_Server_Info *server;
	struct cifs_open_parms oparms;
	struct smb2_create_rsp *o_rsp = NULL;
	struct smb2_query_info_rsp *qi_rsp = NULL;
	int resp_buftype[2];
	struct smb_rqst rqst[2];
	struct kvec rsp_iov[2];
	struct kvec open_iov[SMB2_CREATE_IOV_SIZE];
	struct kvec qi_iov[1];
	int rc, flags = 0;
	__le16 utf16_path = 0; /* Null - since an open of top of share */
	u8 oplock = SMB2_OPLOCK_LEVEL_II;
	struct cifs_fid *pfid;
	struct dentry *dentry;

	if (tcon == NULL || tcon->nohandlecache ||
	    is_smb1_server(tcon->ses->server))
		return -EOPNOTSUPP;

	ses = tcon->ses;
	server = ses->server;

	if (cifs_sb->root == NULL)
		return -ENOENT;

	if (strlen(path))
		return -ENOENT;

	dentry = cifs_sb->root;

	mutex_lock(&tcon->cfid.fid_mutex);
	if (tcon->cfid.is_valid) {
		cifs_dbg(FYI, "found a cached root file handle\n");
		*cfid = &tcon->cfid;
		kref_get(&tcon->cfid.refcount);
		mutex_unlock(&tcon->cfid.fid_mutex);
		return 0;
	}

	/*
	 * We do not hold the lock for the open because in case
	 * SMB2_open needs to reconnect, it will end up calling
	 * cifs_mark_open_files_invalid() which takes the lock again
	 * thus causing a deadlock
	 */

	mutex_unlock(&tcon->cfid.fid_mutex);

	if (smb3_encryption_required(tcon))
		flags |= CIFS_TRANSFORM_REQ;

	if (!server->ops->new_lease_key)
		return -EIO;

	pfid = tcon->cfid.fid;
	server->ops->new_lease_key(pfid);

	memset(rqst, 0, sizeof(rqst));
	resp_buftype[0] = resp_buftype[1] = CIFS_NO_BUFFER;
	memset(rsp_iov, 0, sizeof(rsp_iov));

	/* Open */
	memset(&open_iov, 0, sizeof(open_iov));
	rqst[0].rq_iov = open_iov;
	rqst[0].rq_nvec = SMB2_CREATE_IOV_SIZE;

	oparms.tcon = tcon;
	oparms.create_options = cifs_create_options(cifs_sb, CREATE_NOT_FILE);
	oparms.desired_access = FILE_READ_ATTRIBUTES;
	oparms.disposition = FILE_OPEN;
	oparms.fid = pfid;
	oparms.reconnect = false;

	rc = SMB2_open_init(tcon, server,
			    &rqst[0], &oplock, &oparms, &utf16_path);
	if (rc)
		goto oshr_free;
	smb2_set_next_command(tcon, &rqst[0]);

	memset(&qi_iov, 0, sizeof(qi_iov));
	rqst[1].rq_iov = qi_iov;
	rqst[1].rq_nvec = 1;

	rc = SMB2_query_info_init(tcon, server,
				  &rqst[1], COMPOUND_FID,
				  COMPOUND_FID, FILE_ALL_INFORMATION,
				  SMB2_O_INFO_FILE, 0,
				  sizeof(struct smb2_file_all_info) +
				  PATH_MAX * 2, 0, NULL);
	if (rc)
		goto oshr_free;

	smb2_set_related(&rqst[1]);

	rc = compound_send_recv(xid, ses, server,
				flags, 2, rqst,
				resp_buftype, rsp_iov);
	mutex_lock(&tcon->cfid.fid_mutex);

	/*
	 * Now we need to check again as the cached root might have
	 * been successfully re-opened from a concurrent process
	 */

	if (tcon->cfid.is_valid) {
		/* work was already done */

		/* stash fids for close() later */
		struct cifs_fid fid = {
			.persistent_fid = pfid->persistent_fid,
			.volatile_fid = pfid->volatile_fid,
		};

		/*
		 * caller expects this func to set the fid in cfid to valid
		 * cached root, so increment the refcount.
		 */
		kref_get(&tcon->cfid.refcount);

		mutex_unlock(&tcon->cfid.fid_mutex);

		if (rc == 0) {
			/* close extra handle outside of crit sec */
			SMB2_close(xid, tcon, fid.persistent_fid, fid.volatile_fid);
		}
		rc = 0;
		goto oshr_free;
	}

	/* Cached root is still invalid, continue normaly */

	if (rc) {
		if (rc == -EREMCHG) {
			tcon->need_reconnect = true;
			pr_warn_once("server share %s deleted\n",
				     tcon->treeName);
		}
		goto oshr_exit;
	}

	atomic_inc(&tcon->num_remote_opens);

	o_rsp = (struct smb2_create_rsp *)rsp_iov[0].iov_base;
	oparms.fid->persistent_fid = o_rsp->PersistentFileId;
	oparms.fid->volatile_fid = o_rsp->VolatileFileId;
#ifdef CONFIG_CIFS_DEBUG2
	oparms.fid->mid = le64_to_cpu(o_rsp->hdr.MessageId);
#endif /* CIFS_DEBUG2 */

	tcon->cfid.tcon = tcon;
	tcon->cfid.is_valid = true;
	tcon->cfid.dentry = dentry;
	dget(dentry);
	kref_init(&tcon->cfid.refcount);

	/* BB TBD check to see if oplock level check can be removed below */
	if (o_rsp->OplockLevel == SMB2_OPLOCK_LEVEL_LEASE) {
		/*
		 * See commit 2f94a3125b87. Increment the refcount when we
		 * get a lease for root, release it if lease break occurs
		 */
		kref_get(&tcon->cfid.refcount);
		tcon->cfid.has_lease = true;
		smb2_parse_contexts(server, o_rsp,
				&oparms.fid->epoch,
				    oparms.fid->lease_key, &oplock,
				    NULL, NULL);
	} else
		goto oshr_exit;

	qi_rsp = (struct smb2_query_info_rsp *)rsp_iov[1].iov_base;
	if (le32_to_cpu(qi_rsp->OutputBufferLength) < sizeof(struct smb2_file_all_info))
		goto oshr_exit;
	if (!smb2_validate_and_copy_iov(
				le16_to_cpu(qi_rsp->OutputBufferOffset),
				sizeof(struct smb2_file_all_info),
				&rsp_iov[1], sizeof(struct smb2_file_all_info),
				(char *)&tcon->cfid.file_all_info))
		tcon->cfid.file_all_info_is_valid = true;
	tcon->cfid.time = jiffies;


oshr_exit:
	mutex_unlock(&tcon->cfid.fid_mutex);
oshr_free:
	SMB2_open_free(&rqst[0]);
	SMB2_query_info_free(&rqst[1]);
	free_rsp_buf(resp_buftype[0], rsp_iov[0].iov_base);
	free_rsp_buf(resp_buftype[1], rsp_iov[1].iov_base);
	if (rc == 0)
		*cfid = &tcon->cfid;

	return rc;
}

int open_cached_dir_by_dentry(struct cifs_tcon *tcon,
			      struct dentry *dentry,
			      struct cached_fid **cfid)
{
	mutex_lock(&tcon->cfid.fid_mutex);
	if (tcon->cfid.dentry == dentry) {
		cifs_dbg(FYI, "found a cached root file handle by dentry\n");
		*cfid = &tcon->cfid;
		kref_get(&tcon->cfid.refcount);
		mutex_unlock(&tcon->cfid.fid_mutex);
		return 0;
	}
	mutex_unlock(&tcon->cfid.fid_mutex);
	return -ENOENT;
}

static void
smb2_close_cached_fid(struct kref *ref)
{
	struct cached_fid *cfid = container_of(ref, struct cached_fid,
					       refcount);
	struct cached_dirent *dirent, *q;

	if (cfid->is_valid) {
		cifs_dbg(FYI, "clear cached root file handle\n");
		SMB2_close(0, cfid->tcon, cfid->fid->persistent_fid,
			   cfid->fid->volatile_fid);
	}

	/*
	 * We only check validity above to send SMB2_close,
	 * but we still need to invalidate these entries
	 * when this function is called
	 */
	cfid->is_valid = false;
	cfid->file_all_info_is_valid = false;
	cfid->has_lease = false;
	if (cfid->dentry) {
		dput(cfid->dentry);
		cfid->dentry = NULL;
	}
	/*
	 * Delete all cached dirent names
	 */
	mutex_lock(&cfid->dirents.de_mutex);
	list_for_each_entry_safe(dirent, q, &cfid->dirents.entries, entry) {
		list_del(&dirent->entry);
		kfree(dirent->name);
		kfree(dirent);
	}
	cfid->dirents.is_valid = 0;
	cfid->dirents.is_failed = 0;
	cfid->dirents.ctx = NULL;
	cfid->dirents.pos = 0;
	mutex_unlock(&cfid->dirents.de_mutex);

}

void close_cached_dir(struct cached_fid *cfid)
{
	mutex_lock(&cfid->fid_mutex);
	kref_put(&cfid->refcount, smb2_close_cached_fid);
	mutex_unlock(&cfid->fid_mutex);
}

void close_cached_dir_lease_locked(struct cached_fid *cfid)
{
	if (cfid->has_lease) {
		cfid->has_lease = false;
		kref_put(&cfid->refcount, smb2_close_cached_fid);
	}
}

void close_cached_dir_lease(struct cached_fid *cfid)
{
	mutex_lock(&cfid->fid_mutex);
	close_cached_dir_lease_locked(cfid);
	mutex_unlock(&cfid->fid_mutex);
}

/*
 * Called from cifs_kill_sb when we unmount a share
 */
void close_all_cached_dirs(struct cifs_sb_info *cifs_sb)
{
	struct rb_root *root = &cifs_sb->tlink_tree;
	struct rb_node *node;
	struct cached_fid *cfid;
	struct cifs_tcon *tcon;
	struct tcon_link *tlink;

	for (node = rb_first(root); node; node = rb_next(node)) {
		tlink = rb_entry(node, struct tcon_link, tl_rbnode);
		tcon = tlink_tcon(tlink);
		if (IS_ERR(tcon))
			continue;
		cfid = &tcon->cfid;
		mutex_lock(&cfid->fid_mutex);
		if (cfid->dentry) {
			dput(cfid->dentry);
			cfid->dentry = NULL;
		}
		mutex_unlock(&cfid->fid_mutex);
	}
}

/*
 * Invalidate and close all cached dirs when a TCON has been reset
 * due to a session loss.
 */
void invalidate_all_cached_dirs(struct cifs_tcon *tcon)
{
	mutex_lock(&tcon->cfid.fid_mutex);
	tcon->cfid.is_valid = false;
	/* cached handle is not valid, so SMB2_CLOSE won't be sent below */
	close_cached_dir_lease_locked(&tcon->cfid);
	memset(tcon->cfid.fid, 0, sizeof(struct cifs_fid));
	mutex_unlock(&tcon->cfid.fid_mutex);
}

static void
smb2_cached_lease_break(struct work_struct *work)
{
	struct cached_fid *cfid = container_of(work,
				struct cached_fid, lease_break);

	close_cached_dir_lease(cfid);
}

int cached_dir_lease_break(struct cifs_tcon *tcon, __u8 lease_key[16])
{
	if (tcon->cfid.is_valid &&
	    !memcmp(lease_key,
		    tcon->cfid.fid->lease_key,
		    SMB2_LEASE_KEY_SIZE)) {
		tcon->cfid.time = 0;
		INIT_WORK(&tcon->cfid.lease_break,
			  smb2_cached_lease_break);
		queue_work(cifsiod_wq,
			   &tcon->cfid.lease_break);
		return true;
	}
	return false;
}