1 // SPDX-License-Identifier: LGPL-2.1
2 /*
3  *
4  *   vfs operations that deal with dentries
5  *
6  *   Copyright (C) International Business Machines  Corp., 2002,2009
7  *   Author(s): Steve French (sfrench@us.ibm.com)
8  *
9  */
10 #include <linux/fs.h>
11 #include <linux/stat.h>
12 #include <linux/slab.h>
13 #include <linux/namei.h>
14 #include <linux/mount.h>
15 #include <linux/file.h>
16 #include "cifsfs.h"
17 #include "cifspdu.h"
18 #include "cifsglob.h"
19 #include "cifsproto.h"
20 #include "cifs_debug.h"
21 #include "cifs_fs_sb.h"
22 #include "cifs_unicode.h"
23 #include "fs_context.h"
24 #include "cifs_ioctl.h"
25 #include "fscache.h"
26 
27 static void
renew_parental_timestamps(struct dentry * direntry)28 renew_parental_timestamps(struct dentry *direntry)
29 {
30 	/* BB check if there is a way to get the kernel to do this or if we
31 	   really need this */
32 	do {
33 		cifs_set_time(direntry, jiffies);
34 		direntry = direntry->d_parent;
35 	} while (!IS_ROOT(direntry));
36 }
37 
38 char *
cifs_build_path_to_root(struct smb3_fs_context * ctx,struct cifs_sb_info * cifs_sb,struct cifs_tcon * tcon,int add_treename)39 cifs_build_path_to_root(struct smb3_fs_context *ctx, struct cifs_sb_info *cifs_sb,
40 			struct cifs_tcon *tcon, int add_treename)
41 {
42 	int pplen = ctx->prepath ? strlen(ctx->prepath) + 1 : 0;
43 	int dfsplen;
44 	char *full_path = NULL;
45 
46 	/* if no prefix path, simply set path to the root of share to "" */
47 	if (pplen == 0) {
48 		full_path = kzalloc(1, GFP_KERNEL);
49 		return full_path;
50 	}
51 
52 	if (add_treename)
53 		dfsplen = strnlen(tcon->tree_name, MAX_TREE_SIZE + 1);
54 	else
55 		dfsplen = 0;
56 
57 	full_path = kmalloc(dfsplen + pplen + 1, GFP_KERNEL);
58 	if (full_path == NULL)
59 		return full_path;
60 
61 	if (dfsplen)
62 		memcpy(full_path, tcon->tree_name, dfsplen);
63 	full_path[dfsplen] = CIFS_DIR_SEP(cifs_sb);
64 	memcpy(full_path + dfsplen + 1, ctx->prepath, pplen);
65 	convert_delimiter(full_path, CIFS_DIR_SEP(cifs_sb));
66 	return full_path;
67 }
68 
69 /* Note: caller must free return buffer */
70 const char *
build_path_from_dentry(struct dentry * direntry,void * page)71 build_path_from_dentry(struct dentry *direntry, void *page)
72 {
73 	struct cifs_sb_info *cifs_sb = CIFS_SB(direntry->d_sb);
74 	struct cifs_tcon *tcon = cifs_sb_master_tcon(cifs_sb);
75 	bool prefix = tcon->Flags & SMB_SHARE_IS_IN_DFS;
76 
77 	return build_path_from_dentry_optional_prefix(direntry, page,
78 						      prefix);
79 }
80 
81 char *
build_path_from_dentry_optional_prefix(struct dentry * direntry,void * page,bool prefix)82 build_path_from_dentry_optional_prefix(struct dentry *direntry, void *page,
83 				       bool prefix)
84 {
85 	int dfsplen;
86 	int pplen = 0;
87 	struct cifs_sb_info *cifs_sb = CIFS_SB(direntry->d_sb);
88 	struct cifs_tcon *tcon = cifs_sb_master_tcon(cifs_sb);
89 	char dirsep = CIFS_DIR_SEP(cifs_sb);
90 	char *s;
91 
92 	if (unlikely(!page))
93 		return ERR_PTR(-ENOMEM);
94 
95 	if (prefix)
96 		dfsplen = strnlen(tcon->tree_name, MAX_TREE_SIZE + 1);
97 	else
98 		dfsplen = 0;
99 
100 	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_USE_PREFIX_PATH)
101 		pplen = cifs_sb->prepath ? strlen(cifs_sb->prepath) + 1 : 0;
102 
103 	s = dentry_path_raw(direntry, page, PATH_MAX);
104 	if (IS_ERR(s))
105 		return s;
106 	if (!s[1])	// for root we want "", not "/"
107 		s++;
108 	if (s < (char *)page + pplen + dfsplen)
109 		return ERR_PTR(-ENAMETOOLONG);
110 	if (pplen) {
111 		cifs_dbg(FYI, "using cifs_sb prepath <%s>\n", cifs_sb->prepath);
112 		s -= pplen;
113 		memcpy(s + 1, cifs_sb->prepath, pplen - 1);
114 		*s = '/';
115 	}
116 	if (dirsep != '/') {
117 		/* BB test paths to Windows with '/' in the midst of prepath */
118 		char *p;
119 
120 		for (p = s; *p; p++)
121 			if (*p == '/')
122 				*p = dirsep;
123 	}
124 	if (dfsplen) {
125 		s -= dfsplen;
126 		memcpy(s, tcon->tree_name, dfsplen);
127 		if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_POSIX_PATHS) {
128 			int i;
129 			for (i = 0; i < dfsplen; i++) {
130 				if (s[i] == '\\')
131 					s[i] = '/';
132 			}
133 		}
134 	}
135 	return s;
136 }
137 
138 /*
139  * Don't allow path components longer than the server max.
140  * Don't allow the separator character in a path component.
141  * The VFS will not allow "/", but "\" is allowed by posix.
142  */
143 static int
check_name(struct dentry * direntry,struct cifs_tcon * tcon)144 check_name(struct dentry *direntry, struct cifs_tcon *tcon)
145 {
146 	struct cifs_sb_info *cifs_sb = CIFS_SB(direntry->d_sb);
147 	int i;
148 
149 	if (unlikely(tcon->fsAttrInfo.MaxPathNameComponentLength &&
150 		     direntry->d_name.len >
151 		     le32_to_cpu(tcon->fsAttrInfo.MaxPathNameComponentLength)))
152 		return -ENAMETOOLONG;
153 
154 	if (!(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_POSIX_PATHS)) {
155 		for (i = 0; i < direntry->d_name.len; i++) {
156 			if (direntry->d_name.name[i] == '\\') {
157 				cifs_dbg(FYI, "Invalid file name\n");
158 				return -EINVAL;
159 			}
160 		}
161 	}
162 	return 0;
163 }
164 
165 
166 /* Inode operations in similar order to how they appear in Linux file fs.h */
167 
cifs_do_create(struct inode * inode,struct dentry * direntry,unsigned int xid,struct tcon_link * tlink,unsigned int oflags,umode_t mode,__u32 * oplock,struct cifs_fid * fid,struct cifs_open_info_data * buf)168 static int cifs_do_create(struct inode *inode, struct dentry *direntry, unsigned int xid,
169 			  struct tcon_link *tlink, unsigned int oflags, umode_t mode, __u32 *oplock,
170 			  struct cifs_fid *fid, struct cifs_open_info_data *buf)
171 {
172 	int rc = -ENOENT;
173 	int create_options = CREATE_NOT_DIR;
174 	int desired_access;
175 	struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
176 	struct cifs_tcon *tcon = tlink_tcon(tlink);
177 	const char *full_path;
178 	void *page = alloc_dentry_path();
179 	struct inode *newinode = NULL;
180 	int disposition;
181 	struct TCP_Server_Info *server = tcon->ses->server;
182 	struct cifs_open_parms oparms;
183 
184 	*oplock = 0;
185 	if (tcon->ses->server->oplocks)
186 		*oplock = REQ_OPLOCK;
187 
188 	full_path = build_path_from_dentry(direntry, page);
189 	if (IS_ERR(full_path)) {
190 		free_dentry_path(page);
191 		return PTR_ERR(full_path);
192 	}
193 
194 #ifdef CONFIG_CIFS_ALLOW_INSECURE_LEGACY
195 	if (tcon->unix_ext && cap_unix(tcon->ses) && !tcon->broken_posix_open &&
196 	    (CIFS_UNIX_POSIX_PATH_OPS_CAP &
197 			le64_to_cpu(tcon->fsUnixInfo.Capability))) {
198 		rc = cifs_posix_open(full_path, &newinode, inode->i_sb, mode,
199 				     oflags, oplock, &fid->netfid, xid);
200 		switch (rc) {
201 		case 0:
202 			if (newinode == NULL) {
203 				/* query inode info */
204 				goto cifs_create_get_file_info;
205 			}
206 
207 			if (S_ISDIR(newinode->i_mode)) {
208 				CIFSSMBClose(xid, tcon, fid->netfid);
209 				iput(newinode);
210 				rc = -EISDIR;
211 				goto out;
212 			}
213 
214 			if (!S_ISREG(newinode->i_mode)) {
215 				/*
216 				 * The server may allow us to open things like
217 				 * FIFOs, but the client isn't set up to deal
218 				 * with that. If it's not a regular file, just
219 				 * close it and proceed as if it were a normal
220 				 * lookup.
221 				 */
222 				CIFSSMBClose(xid, tcon, fid->netfid);
223 				goto cifs_create_get_file_info;
224 			}
225 			/* success, no need to query */
226 			goto cifs_create_set_dentry;
227 
228 		case -ENOENT:
229 			goto cifs_create_get_file_info;
230 
231 		case -EIO:
232 		case -EINVAL:
233 			/*
234 			 * EIO could indicate that (posix open) operation is not
235 			 * supported, despite what server claimed in capability
236 			 * negotiation.
237 			 *
238 			 * POSIX open in samba versions 3.3.1 and earlier could
239 			 * incorrectly fail with invalid parameter.
240 			 */
241 			tcon->broken_posix_open = true;
242 			break;
243 
244 		case -EREMOTE:
245 		case -EOPNOTSUPP:
246 			/*
247 			 * EREMOTE indicates DFS junction, which is not handled
248 			 * in posix open.  If either that or op not supported
249 			 * returned, follow the normal lookup.
250 			 */
251 			break;
252 
253 		default:
254 			goto out;
255 		}
256 		/*
257 		 * fallthrough to retry, using older open call, this is case
258 		 * where server does not support this SMB level, and falsely
259 		 * claims capability (also get here for DFS case which should be
260 		 * rare for path not covered on files)
261 		 */
262 	}
263 #endif /* CONFIG_CIFS_ALLOW_INSECURE_LEGACY */
264 
265 	desired_access = 0;
266 	if (OPEN_FMODE(oflags) & FMODE_READ)
267 		desired_access |= GENERIC_READ; /* is this too little? */
268 	if (OPEN_FMODE(oflags) & FMODE_WRITE)
269 		desired_access |= GENERIC_WRITE;
270 
271 	disposition = FILE_OVERWRITE_IF;
272 	if ((oflags & (O_CREAT | O_EXCL)) == (O_CREAT | O_EXCL))
273 		disposition = FILE_CREATE;
274 	else if ((oflags & (O_CREAT | O_TRUNC)) == (O_CREAT | O_TRUNC))
275 		disposition = FILE_OVERWRITE_IF;
276 	else if ((oflags & O_CREAT) == O_CREAT)
277 		disposition = FILE_OPEN_IF;
278 	else
279 		cifs_dbg(FYI, "Create flag not set in create function\n");
280 
281 	/*
282 	 * BB add processing to set equivalent of mode - e.g. via CreateX with
283 	 * ACLs
284 	 */
285 
286 	if (!server->ops->open) {
287 		rc = -ENOSYS;
288 		goto out;
289 	}
290 
291 	/*
292 	 * if we're not using unix extensions, see if we need to set
293 	 * ATTR_READONLY on the create call
294 	 */
295 	if (!tcon->unix_ext && (mode & S_IWUGO) == 0)
296 		create_options |= CREATE_OPTION_READONLY;
297 
298 	oparms.tcon = tcon;
299 	oparms.cifs_sb = cifs_sb;
300 	oparms.desired_access = desired_access;
301 	oparms.create_options = cifs_create_options(cifs_sb, create_options);
302 	oparms.disposition = disposition;
303 	oparms.path = full_path;
304 	oparms.fid = fid;
305 	oparms.reconnect = false;
306 	oparms.mode = mode;
307 	rc = server->ops->open(xid, &oparms, oplock, buf);
308 	if (rc) {
309 		cifs_dbg(FYI, "cifs_create returned 0x%x\n", rc);
310 		goto out;
311 	}
312 
313 #ifdef CONFIG_CIFS_ALLOW_INSECURE_LEGACY
314 	/*
315 	 * If Open reported that we actually created a file then we now have to
316 	 * set the mode if possible.
317 	 */
318 	if ((tcon->unix_ext) && (*oplock & CIFS_CREATE_ACTION)) {
319 		struct cifs_unix_set_info_args args = {
320 				.mode	= mode,
321 				.ctime	= NO_CHANGE_64,
322 				.atime	= NO_CHANGE_64,
323 				.mtime	= NO_CHANGE_64,
324 				.device	= 0,
325 		};
326 
327 		if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SET_UID) {
328 			args.uid = current_fsuid();
329 			if (inode->i_mode & S_ISGID)
330 				args.gid = inode->i_gid;
331 			else
332 				args.gid = current_fsgid();
333 		} else {
334 			args.uid = INVALID_UID; /* no change */
335 			args.gid = INVALID_GID; /* no change */
336 		}
337 		CIFSSMBUnixSetFileInfo(xid, tcon, &args, fid->netfid,
338 				       current->tgid);
339 	} else {
340 		/*
341 		 * BB implement mode setting via Windows security
342 		 * descriptors e.g.
343 		 */
344 		/* CIFSSMBWinSetPerms(xid,tcon,path,mode,-1,-1,nls);*/
345 
346 		/* Could set r/o dos attribute if mode & 0222 == 0 */
347 	}
348 
349 cifs_create_get_file_info:
350 	/* server might mask mode so we have to query for it */
351 	if (tcon->unix_ext)
352 		rc = cifs_get_inode_info_unix(&newinode, full_path, inode->i_sb,
353 					      xid);
354 	else {
355 #else
356 	{
357 #endif /* CONFIG_CIFS_ALLOW_INSECURE_LEGACY */
358 		/* TODO: Add support for calling POSIX query info here, but passing in fid */
359 		rc = cifs_get_inode_info(&newinode, full_path, buf, inode->i_sb, xid, fid);
360 		if (newinode) {
361 			if (server->ops->set_lease_key)
362 				server->ops->set_lease_key(newinode, fid);
363 			if ((*oplock & CIFS_CREATE_ACTION) && S_ISREG(newinode->i_mode)) {
364 				if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_DYNPERM)
365 					newinode->i_mode = mode;
366 				if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SET_UID) {
367 					newinode->i_uid = current_fsuid();
368 					if (inode->i_mode & S_ISGID)
369 						newinode->i_gid = inode->i_gid;
370 					else
371 						newinode->i_gid = current_fsgid();
372 				}
373 			}
374 		}
375 	}
376 
377 #ifdef CONFIG_CIFS_ALLOW_INSECURE_LEGACY
378 cifs_create_set_dentry:
379 #endif /* CONFIG_CIFS_ALLOW_INSECURE_LEGACY */
380 	if (rc != 0) {
381 		cifs_dbg(FYI, "Create worked, get_inode_info failed rc = %d\n",
382 			 rc);
383 		goto out_err;
384 	}
385 
386 	if (newinode)
387 		if (S_ISDIR(newinode->i_mode)) {
388 			rc = -EISDIR;
389 			goto out_err;
390 		}
391 
392 	d_drop(direntry);
393 	d_add(direntry, newinode);
394 
395 out:
396 	free_dentry_path(page);
397 	return rc;
398 
399 out_err:
400 	if (server->ops->close)
401 		server->ops->close(xid, tcon, fid);
402 	if (newinode)
403 		iput(newinode);
404 	goto out;
405 }
406 
407 int
408 cifs_atomic_open(struct inode *inode, struct dentry *direntry,
409 		 struct file *file, unsigned oflags, umode_t mode)
410 {
411 	int rc;
412 	unsigned int xid;
413 	struct tcon_link *tlink;
414 	struct cifs_tcon *tcon;
415 	struct TCP_Server_Info *server;
416 	struct cifs_fid fid = {};
417 	struct cifs_pending_open open;
418 	__u32 oplock;
419 	struct cifsFileInfo *file_info;
420 	struct cifs_open_info_data buf = {};
421 
422 	if (unlikely(cifs_forced_shutdown(CIFS_SB(inode->i_sb))))
423 		return -EIO;
424 
425 	/*
426 	 * Posix open is only called (at lookup time) for file create now. For
427 	 * opens (rather than creates), because we do not know if it is a file
428 	 * or directory yet, and current Samba no longer allows us to do posix
429 	 * open on dirs, we could end up wasting an open call on what turns out
430 	 * to be a dir. For file opens, we wait to call posix open till
431 	 * cifs_open.  It could be added to atomic_open in the future but the
432 	 * performance tradeoff of the extra network request when EISDIR or
433 	 * EACCES is returned would have to be weighed against the 50% reduction
434 	 * in network traffic in the other paths.
435 	 */
436 	if (!(oflags & O_CREAT)) {
437 		struct dentry *res;
438 
439 		/*
440 		 * Check for hashed negative dentry. We have already revalidated
441 		 * the dentry and it is fine. No need to perform another lookup.
442 		 */
443 		if (!d_in_lookup(direntry))
444 			return -ENOENT;
445 
446 		res = cifs_lookup(inode, direntry, 0);
447 		if (IS_ERR(res))
448 			return PTR_ERR(res);
449 
450 		return finish_no_open(file, res);
451 	}
452 
453 	xid = get_xid();
454 
455 	cifs_dbg(FYI, "parent inode = 0x%p name is: %pd and dentry = 0x%p\n",
456 		 inode, direntry, direntry);
457 
458 	tlink = cifs_sb_tlink(CIFS_SB(inode->i_sb));
459 	if (IS_ERR(tlink)) {
460 		rc = PTR_ERR(tlink);
461 		goto out_free_xid;
462 	}
463 
464 	tcon = tlink_tcon(tlink);
465 
466 	rc = check_name(direntry, tcon);
467 	if (rc)
468 		goto out;
469 
470 	server = tcon->ses->server;
471 
472 	if (server->ops->new_lease_key)
473 		server->ops->new_lease_key(&fid);
474 
475 	cifs_add_pending_open(&fid, tlink, &open);
476 
477 	rc = cifs_do_create(inode, direntry, xid, tlink, oflags, mode,
478 			    &oplock, &fid, &buf);
479 	if (rc) {
480 		cifs_del_pending_open(&open);
481 		goto out;
482 	}
483 
484 	if ((oflags & (O_CREAT | O_EXCL)) == (O_CREAT | O_EXCL))
485 		file->f_mode |= FMODE_CREATED;
486 
487 	rc = finish_open(file, direntry, generic_file_open);
488 	if (rc) {
489 		if (server->ops->close)
490 			server->ops->close(xid, tcon, &fid);
491 		cifs_del_pending_open(&open);
492 		goto out;
493 	}
494 
495 	if (file->f_flags & O_DIRECT &&
496 	    CIFS_SB(inode->i_sb)->mnt_cifs_flags & CIFS_MOUNT_STRICT_IO) {
497 		if (CIFS_SB(inode->i_sb)->mnt_cifs_flags & CIFS_MOUNT_NO_BRL)
498 			file->f_op = &cifs_file_direct_nobrl_ops;
499 		else
500 			file->f_op = &cifs_file_direct_ops;
501 		}
502 
503 	file_info = cifs_new_fileinfo(&fid, file, tlink, oplock, buf.symlink_target);
504 	if (file_info == NULL) {
505 		if (server->ops->close)
506 			server->ops->close(xid, tcon, &fid);
507 		cifs_del_pending_open(&open);
508 		rc = -ENOMEM;
509 		goto out;
510 	}
511 
512 	fscache_use_cookie(cifs_inode_cookie(file_inode(file)),
513 			   file->f_mode & FMODE_WRITE);
514 
515 out:
516 	cifs_put_tlink(tlink);
517 out_free_xid:
518 	free_xid(xid);
519 	cifs_free_open_info(&buf);
520 	return rc;
521 }
522 
523 int cifs_create(struct user_namespace *mnt_userns, struct inode *inode,
524 		struct dentry *direntry, umode_t mode, bool excl)
525 {
526 	int rc;
527 	unsigned int xid = get_xid();
528 	/*
529 	 * BB below access is probably too much for mknod to request
530 	 *    but we have to do query and setpathinfo so requesting
531 	 *    less could fail (unless we want to request getatr and setatr
532 	 *    permissions (only).  At least for POSIX we do not have to
533 	 *    request so much.
534 	 */
535 	unsigned oflags = O_EXCL | O_CREAT | O_RDWR;
536 	struct tcon_link *tlink;
537 	struct cifs_tcon *tcon;
538 	struct TCP_Server_Info *server;
539 	struct cifs_fid fid;
540 	__u32 oplock;
541 	struct cifs_open_info_data buf = {};
542 
543 	cifs_dbg(FYI, "cifs_create parent inode = 0x%p name is: %pd and dentry = 0x%p\n",
544 		 inode, direntry, direntry);
545 
546 	if (unlikely(cifs_forced_shutdown(CIFS_SB(inode->i_sb)))) {
547 		rc = -EIO;
548 		goto out_free_xid;
549 	}
550 
551 	tlink = cifs_sb_tlink(CIFS_SB(inode->i_sb));
552 	rc = PTR_ERR(tlink);
553 	if (IS_ERR(tlink))
554 		goto out_free_xid;
555 
556 	tcon = tlink_tcon(tlink);
557 	server = tcon->ses->server;
558 
559 	if (server->ops->new_lease_key)
560 		server->ops->new_lease_key(&fid);
561 
562 	rc = cifs_do_create(inode, direntry, xid, tlink, oflags, mode, &oplock, &fid, &buf);
563 	if (!rc && server->ops->close)
564 		server->ops->close(xid, tcon, &fid);
565 
566 	cifs_free_open_info(&buf);
567 	cifs_put_tlink(tlink);
568 out_free_xid:
569 	free_xid(xid);
570 	return rc;
571 }
572 
573 int cifs_mknod(struct user_namespace *mnt_userns, struct inode *inode,
574 	       struct dentry *direntry, umode_t mode, dev_t device_number)
575 {
576 	int rc = -EPERM;
577 	unsigned int xid;
578 	struct cifs_sb_info *cifs_sb;
579 	struct tcon_link *tlink;
580 	struct cifs_tcon *tcon;
581 	const char *full_path;
582 	void *page;
583 
584 	if (!old_valid_dev(device_number))
585 		return -EINVAL;
586 
587 	cifs_sb = CIFS_SB(inode->i_sb);
588 	if (unlikely(cifs_forced_shutdown(cifs_sb)))
589 		return -EIO;
590 
591 	tlink = cifs_sb_tlink(cifs_sb);
592 	if (IS_ERR(tlink))
593 		return PTR_ERR(tlink);
594 
595 	page = alloc_dentry_path();
596 	tcon = tlink_tcon(tlink);
597 	xid = get_xid();
598 
599 	full_path = build_path_from_dentry(direntry, page);
600 	if (IS_ERR(full_path)) {
601 		rc = PTR_ERR(full_path);
602 		goto mknod_out;
603 	}
604 
605 	rc = tcon->ses->server->ops->make_node(xid, inode, direntry, tcon,
606 					       full_path, mode,
607 					       device_number);
608 
609 mknod_out:
610 	free_dentry_path(page);
611 	free_xid(xid);
612 	cifs_put_tlink(tlink);
613 	return rc;
614 }
615 
616 struct dentry *
617 cifs_lookup(struct inode *parent_dir_inode, struct dentry *direntry,
618 	    unsigned int flags)
619 {
620 	unsigned int xid;
621 	int rc = 0; /* to get around spurious gcc warning, set to zero here */
622 	struct cifs_sb_info *cifs_sb;
623 	struct tcon_link *tlink;
624 	struct cifs_tcon *pTcon;
625 	struct inode *newInode = NULL;
626 	const char *full_path;
627 	void *page;
628 	int retry_count = 0;
629 
630 	xid = get_xid();
631 
632 	cifs_dbg(FYI, "parent inode = 0x%p name is: %pd and dentry = 0x%p\n",
633 		 parent_dir_inode, direntry, direntry);
634 
635 	/* check whether path exists */
636 
637 	cifs_sb = CIFS_SB(parent_dir_inode->i_sb);
638 	tlink = cifs_sb_tlink(cifs_sb);
639 	if (IS_ERR(tlink)) {
640 		free_xid(xid);
641 		return ERR_CAST(tlink);
642 	}
643 	pTcon = tlink_tcon(tlink);
644 
645 	rc = check_name(direntry, pTcon);
646 	if (unlikely(rc)) {
647 		cifs_put_tlink(tlink);
648 		free_xid(xid);
649 		return ERR_PTR(rc);
650 	}
651 
652 	/* can not grab the rename sem here since it would
653 	deadlock in the cases (beginning of sys_rename itself)
654 	in which we already have the sb rename sem */
655 	page = alloc_dentry_path();
656 	full_path = build_path_from_dentry(direntry, page);
657 	if (IS_ERR(full_path)) {
658 		cifs_put_tlink(tlink);
659 		free_xid(xid);
660 		free_dentry_path(page);
661 		return ERR_CAST(full_path);
662 	}
663 
664 	if (d_really_is_positive(direntry)) {
665 		cifs_dbg(FYI, "non-NULL inode in lookup\n");
666 	} else {
667 		cifs_dbg(FYI, "NULL inode in lookup\n");
668 	}
669 	cifs_dbg(FYI, "Full path: %s inode = 0x%p\n",
670 		 full_path, d_inode(direntry));
671 
672 again:
673 	if (pTcon->posix_extensions)
674 		rc = smb311_posix_get_inode_info(&newInode, full_path, parent_dir_inode->i_sb, xid);
675 	else if (pTcon->unix_ext) {
676 		rc = cifs_get_inode_info_unix(&newInode, full_path,
677 					      parent_dir_inode->i_sb, xid);
678 	} else {
679 		rc = cifs_get_inode_info(&newInode, full_path, NULL,
680 				parent_dir_inode->i_sb, xid, NULL);
681 	}
682 
683 	if (rc == 0) {
684 		/* since paths are not looked up by component - the parent
685 		   directories are presumed to be good here */
686 		renew_parental_timestamps(direntry);
687 	} else if (rc == -EAGAIN && retry_count++ < 10) {
688 		goto again;
689 	} else if (rc == -ENOENT) {
690 		cifs_set_time(direntry, jiffies);
691 		newInode = NULL;
692 	} else {
693 		if (rc != -EACCES) {
694 			cifs_dbg(FYI, "Unexpected lookup error %d\n", rc);
695 			/* We special case check for Access Denied - since that
696 			is a common return code */
697 		}
698 		newInode = ERR_PTR(rc);
699 	}
700 	free_dentry_path(page);
701 	cifs_put_tlink(tlink);
702 	free_xid(xid);
703 	return d_splice_alias(newInode, direntry);
704 }
705 
706 static int
707 cifs_d_revalidate(struct dentry *direntry, unsigned int flags)
708 {
709 	struct inode *inode;
710 	int rc;
711 
712 	if (flags & LOOKUP_RCU)
713 		return -ECHILD;
714 
715 	if (d_really_is_positive(direntry)) {
716 		inode = d_inode(direntry);
717 		if ((flags & LOOKUP_REVAL) && !CIFS_CACHE_READ(CIFS_I(inode)))
718 			CIFS_I(inode)->time = 0; /* force reval */
719 
720 		rc = cifs_revalidate_dentry(direntry);
721 		if (rc) {
722 			cifs_dbg(FYI, "cifs_revalidate_dentry failed with rc=%d", rc);
723 			switch (rc) {
724 			case -ENOENT:
725 			case -ESTALE:
726 				/*
727 				 * Those errors mean the dentry is invalid
728 				 * (file was deleted or recreated)
729 				 */
730 				return 0;
731 			default:
732 				/*
733 				 * Otherwise some unexpected error happened
734 				 * report it as-is to VFS layer
735 				 */
736 				return rc;
737 			}
738 		}
739 		else {
740 			/*
741 			 * If the inode wasn't known to be a dfs entry when
742 			 * the dentry was instantiated, such as when created
743 			 * via ->readdir(), it needs to be set now since the
744 			 * attributes will have been updated by
745 			 * cifs_revalidate_dentry().
746 			 */
747 			if (IS_AUTOMOUNT(inode) &&
748 			   !(direntry->d_flags & DCACHE_NEED_AUTOMOUNT)) {
749 				spin_lock(&direntry->d_lock);
750 				direntry->d_flags |= DCACHE_NEED_AUTOMOUNT;
751 				spin_unlock(&direntry->d_lock);
752 			}
753 
754 			return 1;
755 		}
756 	}
757 
758 	/*
759 	 * This may be nfsd (or something), anyway, we can't see the
760 	 * intent of this. So, since this can be for creation, drop it.
761 	 */
762 	if (!flags)
763 		return 0;
764 
765 	/*
766 	 * Drop the negative dentry, in order to make sure to use the
767 	 * case sensitive name which is specified by user if this is
768 	 * for creation.
769 	 */
770 	if (flags & (LOOKUP_CREATE | LOOKUP_RENAME_TARGET))
771 		return 0;
772 
773 	if (time_after(jiffies, cifs_get_time(direntry) + HZ) || !lookupCacheEnabled)
774 		return 0;
775 
776 	return 1;
777 }
778 
779 /* static int cifs_d_delete(struct dentry *direntry)
780 {
781 	int rc = 0;
782 
783 	cifs_dbg(FYI, "In cifs d_delete, name = %pd\n", direntry);
784 
785 	return rc;
786 }     */
787 
788 const struct dentry_operations cifs_dentry_ops = {
789 	.d_revalidate = cifs_d_revalidate,
790 	.d_automount = cifs_dfs_d_automount,
791 /* d_delete:       cifs_d_delete,      */ /* not needed except for debugging */
792 };
793 
794 static int cifs_ci_hash(const struct dentry *dentry, struct qstr *q)
795 {
796 	struct nls_table *codepage = CIFS_SB(dentry->d_sb)->local_nls;
797 	unsigned long hash;
798 	wchar_t c;
799 	int i, charlen;
800 
801 	hash = init_name_hash(dentry);
802 	for (i = 0; i < q->len; i += charlen) {
803 		charlen = codepage->char2uni(&q->name[i], q->len - i, &c);
804 		/* error out if we can't convert the character */
805 		if (unlikely(charlen < 0))
806 			return charlen;
807 		hash = partial_name_hash(cifs_toupper(c), hash);
808 	}
809 	q->hash = end_name_hash(hash);
810 
811 	return 0;
812 }
813 
814 static int cifs_ci_compare(const struct dentry *dentry,
815 		unsigned int len, const char *str, const struct qstr *name)
816 {
817 	struct nls_table *codepage = CIFS_SB(dentry->d_sb)->local_nls;
818 	wchar_t c1, c2;
819 	int i, l1, l2;
820 
821 	/*
822 	 * We make the assumption here that uppercase characters in the local
823 	 * codepage are always the same length as their lowercase counterparts.
824 	 *
825 	 * If that's ever not the case, then this will fail to match it.
826 	 */
827 	if (name->len != len)
828 		return 1;
829 
830 	for (i = 0; i < len; i += l1) {
831 		/* Convert characters in both strings to UTF-16. */
832 		l1 = codepage->char2uni(&str[i], len - i, &c1);
833 		l2 = codepage->char2uni(&name->name[i], name->len - i, &c2);
834 
835 		/*
836 		 * If we can't convert either character, just declare it to
837 		 * be 1 byte long and compare the original byte.
838 		 */
839 		if (unlikely(l1 < 0 && l2 < 0)) {
840 			if (str[i] != name->name[i])
841 				return 1;
842 			l1 = 1;
843 			continue;
844 		}
845 
846 		/*
847 		 * Here, we again ass|u|me that upper/lowercase versions of
848 		 * a character are the same length in the local NLS.
849 		 */
850 		if (l1 != l2)
851 			return 1;
852 
853 		/* Now compare uppercase versions of these characters */
854 		if (cifs_toupper(c1) != cifs_toupper(c2))
855 			return 1;
856 	}
857 
858 	return 0;
859 }
860 
861 const struct dentry_operations cifs_ci_dentry_ops = {
862 	.d_revalidate = cifs_d_revalidate,
863 	.d_hash = cifs_ci_hash,
864 	.d_compare = cifs_ci_compare,
865 	.d_automount = cifs_dfs_d_automount,
866 };
867