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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 = (struct cifs_open_parms) {
299 		.tcon = tcon,
300 		.cifs_sb = cifs_sb,
301 		.desired_access = desired_access,
302 		.create_options = cifs_create_options(cifs_sb, create_options),
303 		.disposition = disposition,
304 		.path = full_path,
305 		.fid = fid,
306 		.mode = mode,
307 	};
308 	rc = server->ops->open(xid, &oparms, oplock, buf);
309 	if (rc) {
310 		cifs_dbg(FYI, "cifs_create returned 0x%x\n", rc);
311 		goto out;
312 	}
313 
314 #ifdef CONFIG_CIFS_ALLOW_INSECURE_LEGACY
315 	/*
316 	 * If Open reported that we actually created a file then we now have to
317 	 * set the mode if possible.
318 	 */
319 	if ((tcon->unix_ext) && (*oplock & CIFS_CREATE_ACTION)) {
320 		struct cifs_unix_set_info_args args = {
321 				.mode	= mode,
322 				.ctime	= NO_CHANGE_64,
323 				.atime	= NO_CHANGE_64,
324 				.mtime	= NO_CHANGE_64,
325 				.device	= 0,
326 		};
327 
328 		if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SET_UID) {
329 			args.uid = current_fsuid();
330 			if (inode->i_mode & S_ISGID)
331 				args.gid = inode->i_gid;
332 			else
333 				args.gid = current_fsgid();
334 		} else {
335 			args.uid = INVALID_UID; /* no change */
336 			args.gid = INVALID_GID; /* no change */
337 		}
338 		CIFSSMBUnixSetFileInfo(xid, tcon, &args, fid->netfid,
339 				       current->tgid);
340 	} else {
341 		/*
342 		 * BB implement mode setting via Windows security
343 		 * descriptors e.g.
344 		 */
345 		/* CIFSSMBWinSetPerms(xid,tcon,path,mode,-1,-1,nls);*/
346 
347 		/* Could set r/o dos attribute if mode & 0222 == 0 */
348 	}
349 
350 cifs_create_get_file_info:
351 	/* server might mask mode so we have to query for it */
352 	if (tcon->unix_ext)
353 		rc = cifs_get_inode_info_unix(&newinode, full_path, inode->i_sb,
354 					      xid);
355 	else {
356 #else
357 	{
358 #endif /* CONFIG_CIFS_ALLOW_INSECURE_LEGACY */
359 		/* TODO: Add support for calling POSIX query info here, but passing in fid */
360 		rc = cifs_get_inode_info(&newinode, full_path, buf, inode->i_sb, xid, fid);
361 		if (newinode) {
362 			if (server->ops->set_lease_key)
363 				server->ops->set_lease_key(newinode, fid);
364 			if ((*oplock & CIFS_CREATE_ACTION) && S_ISREG(newinode->i_mode)) {
365 				if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_DYNPERM)
366 					newinode->i_mode = mode;
367 				if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SET_UID) {
368 					newinode->i_uid = current_fsuid();
369 					if (inode->i_mode & S_ISGID)
370 						newinode->i_gid = inode->i_gid;
371 					else
372 						newinode->i_gid = current_fsgid();
373 				}
374 			}
375 		}
376 	}
377 
378 #ifdef CONFIG_CIFS_ALLOW_INSECURE_LEGACY
379 cifs_create_set_dentry:
380 #endif /* CONFIG_CIFS_ALLOW_INSECURE_LEGACY */
381 	if (rc != 0) {
382 		cifs_dbg(FYI, "Create worked, get_inode_info failed rc = %d\n",
383 			 rc);
384 		goto out_err;
385 	}
386 
387 	if (newinode)
388 		if (S_ISDIR(newinode->i_mode)) {
389 			rc = -EISDIR;
390 			goto out_err;
391 		}
392 
393 	d_drop(direntry);
394 	d_add(direntry, newinode);
395 
396 out:
397 	free_dentry_path(page);
398 	return rc;
399 
400 out_err:
401 	if (server->ops->close)
402 		server->ops->close(xid, tcon, fid);
403 	if (newinode)
404 		iput(newinode);
405 	goto out;
406 }
407 
408 int
409 cifs_atomic_open(struct inode *inode, struct dentry *direntry,
410 		 struct file *file, unsigned oflags, umode_t mode)
411 {
412 	int rc;
413 	unsigned int xid;
414 	struct tcon_link *tlink;
415 	struct cifs_tcon *tcon;
416 	struct TCP_Server_Info *server;
417 	struct cifs_fid fid = {};
418 	struct cifs_pending_open open;
419 	__u32 oplock;
420 	struct cifsFileInfo *file_info;
421 	struct cifs_open_info_data buf = {};
422 
423 	if (unlikely(cifs_forced_shutdown(CIFS_SB(inode->i_sb))))
424 		return -EIO;
425 
426 	/*
427 	 * Posix open is only called (at lookup time) for file create now. For
428 	 * opens (rather than creates), because we do not know if it is a file
429 	 * or directory yet, and current Samba no longer allows us to do posix
430 	 * open on dirs, we could end up wasting an open call on what turns out
431 	 * to be a dir. For file opens, we wait to call posix open till
432 	 * cifs_open.  It could be added to atomic_open in the future but the
433 	 * performance tradeoff of the extra network request when EISDIR or
434 	 * EACCES is returned would have to be weighed against the 50% reduction
435 	 * in network traffic in the other paths.
436 	 */
437 	if (!(oflags & O_CREAT)) {
438 		struct dentry *res;
439 
440 		/*
441 		 * Check for hashed negative dentry. We have already revalidated
442 		 * the dentry and it is fine. No need to perform another lookup.
443 		 */
444 		if (!d_in_lookup(direntry))
445 			return -ENOENT;
446 
447 		res = cifs_lookup(inode, direntry, 0);
448 		if (IS_ERR(res))
449 			return PTR_ERR(res);
450 
451 		return finish_no_open(file, res);
452 	}
453 
454 	xid = get_xid();
455 
456 	cifs_dbg(FYI, "parent inode = 0x%p name is: %pd and dentry = 0x%p\n",
457 		 inode, direntry, direntry);
458 
459 	tlink = cifs_sb_tlink(CIFS_SB(inode->i_sb));
460 	if (IS_ERR(tlink)) {
461 		rc = PTR_ERR(tlink);
462 		goto out_free_xid;
463 	}
464 
465 	tcon = tlink_tcon(tlink);
466 
467 	rc = check_name(direntry, tcon);
468 	if (rc)
469 		goto out;
470 
471 	server = tcon->ses->server;
472 
473 	if (server->ops->new_lease_key)
474 		server->ops->new_lease_key(&fid);
475 
476 	cifs_add_pending_open(&fid, tlink, &open);
477 
478 	rc = cifs_do_create(inode, direntry, xid, tlink, oflags, mode,
479 			    &oplock, &fid, &buf);
480 	if (rc) {
481 		cifs_del_pending_open(&open);
482 		goto out;
483 	}
484 
485 	if ((oflags & (O_CREAT | O_EXCL)) == (O_CREAT | O_EXCL))
486 		file->f_mode |= FMODE_CREATED;
487 
488 	rc = finish_open(file, direntry, generic_file_open);
489 	if (rc) {
490 		if (server->ops->close)
491 			server->ops->close(xid, tcon, &fid);
492 		cifs_del_pending_open(&open);
493 		goto out;
494 	}
495 
496 	if (file->f_flags & O_DIRECT &&
497 	    CIFS_SB(inode->i_sb)->mnt_cifs_flags & CIFS_MOUNT_STRICT_IO) {
498 		if (CIFS_SB(inode->i_sb)->mnt_cifs_flags & CIFS_MOUNT_NO_BRL)
499 			file->f_op = &cifs_file_direct_nobrl_ops;
500 		else
501 			file->f_op = &cifs_file_direct_ops;
502 		}
503 
504 	file_info = cifs_new_fileinfo(&fid, file, tlink, oplock, buf.symlink_target);
505 	if (file_info == NULL) {
506 		if (server->ops->close)
507 			server->ops->close(xid, tcon, &fid);
508 		cifs_del_pending_open(&open);
509 		rc = -ENOMEM;
510 		goto out;
511 	}
512 
513 	fscache_use_cookie(cifs_inode_cookie(file_inode(file)),
514 			   file->f_mode & FMODE_WRITE);
515 
516 out:
517 	cifs_put_tlink(tlink);
518 out_free_xid:
519 	free_xid(xid);
520 	cifs_free_open_info(&buf);
521 	return rc;
522 }
523 
524 int cifs_create(struct user_namespace *mnt_userns, struct inode *inode,
525 		struct dentry *direntry, umode_t mode, bool excl)
526 {
527 	int rc;
528 	unsigned int xid = get_xid();
529 	/*
530 	 * BB below access is probably too much for mknod to request
531 	 *    but we have to do query and setpathinfo so requesting
532 	 *    less could fail (unless we want to request getatr and setatr
533 	 *    permissions (only).  At least for POSIX we do not have to
534 	 *    request so much.
535 	 */
536 	unsigned oflags = O_EXCL | O_CREAT | O_RDWR;
537 	struct tcon_link *tlink;
538 	struct cifs_tcon *tcon;
539 	struct TCP_Server_Info *server;
540 	struct cifs_fid fid;
541 	__u32 oplock;
542 	struct cifs_open_info_data buf = {};
543 
544 	cifs_dbg(FYI, "cifs_create parent inode = 0x%p name is: %pd and dentry = 0x%p\n",
545 		 inode, direntry, direntry);
546 
547 	if (unlikely(cifs_forced_shutdown(CIFS_SB(inode->i_sb)))) {
548 		rc = -EIO;
549 		goto out_free_xid;
550 	}
551 
552 	tlink = cifs_sb_tlink(CIFS_SB(inode->i_sb));
553 	rc = PTR_ERR(tlink);
554 	if (IS_ERR(tlink))
555 		goto out_free_xid;
556 
557 	tcon = tlink_tcon(tlink);
558 	server = tcon->ses->server;
559 
560 	if (server->ops->new_lease_key)
561 		server->ops->new_lease_key(&fid);
562 
563 	rc = cifs_do_create(inode, direntry, xid, tlink, oflags, mode, &oplock, &fid, &buf);
564 	if (!rc && server->ops->close)
565 		server->ops->close(xid, tcon, &fid);
566 
567 	cifs_free_open_info(&buf);
568 	cifs_put_tlink(tlink);
569 out_free_xid:
570 	free_xid(xid);
571 	return rc;
572 }
573 
574 int cifs_mknod(struct user_namespace *mnt_userns, struct inode *inode,
575 	       struct dentry *direntry, umode_t mode, dev_t device_number)
576 {
577 	int rc = -EPERM;
578 	unsigned int xid;
579 	struct cifs_sb_info *cifs_sb;
580 	struct tcon_link *tlink;
581 	struct cifs_tcon *tcon;
582 	const char *full_path;
583 	void *page;
584 
585 	if (!old_valid_dev(device_number))
586 		return -EINVAL;
587 
588 	cifs_sb = CIFS_SB(inode->i_sb);
589 	if (unlikely(cifs_forced_shutdown(cifs_sb)))
590 		return -EIO;
591 
592 	tlink = cifs_sb_tlink(cifs_sb);
593 	if (IS_ERR(tlink))
594 		return PTR_ERR(tlink);
595 
596 	page = alloc_dentry_path();
597 	tcon = tlink_tcon(tlink);
598 	xid = get_xid();
599 
600 	full_path = build_path_from_dentry(direntry, page);
601 	if (IS_ERR(full_path)) {
602 		rc = PTR_ERR(full_path);
603 		goto mknod_out;
604 	}
605 
606 	rc = tcon->ses->server->ops->make_node(xid, inode, direntry, tcon,
607 					       full_path, mode,
608 					       device_number);
609 
610 mknod_out:
611 	free_dentry_path(page);
612 	free_xid(xid);
613 	cifs_put_tlink(tlink);
614 	return rc;
615 }
616 
617 struct dentry *
618 cifs_lookup(struct inode *parent_dir_inode, struct dentry *direntry,
619 	    unsigned int flags)
620 {
621 	unsigned int xid;
622 	int rc = 0; /* to get around spurious gcc warning, set to zero here */
623 	struct cifs_sb_info *cifs_sb;
624 	struct tcon_link *tlink;
625 	struct cifs_tcon *pTcon;
626 	struct inode *newInode = NULL;
627 	const char *full_path;
628 	void *page;
629 	int retry_count = 0;
630 
631 	xid = get_xid();
632 
633 	cifs_dbg(FYI, "parent inode = 0x%p name is: %pd and dentry = 0x%p\n",
634 		 parent_dir_inode, direntry, direntry);
635 
636 	/* check whether path exists */
637 
638 	cifs_sb = CIFS_SB(parent_dir_inode->i_sb);
639 	tlink = cifs_sb_tlink(cifs_sb);
640 	if (IS_ERR(tlink)) {
641 		free_xid(xid);
642 		return ERR_CAST(tlink);
643 	}
644 	pTcon = tlink_tcon(tlink);
645 
646 	rc = check_name(direntry, pTcon);
647 	if (unlikely(rc)) {
648 		cifs_put_tlink(tlink);
649 		free_xid(xid);
650 		return ERR_PTR(rc);
651 	}
652 
653 	/* can not grab the rename sem here since it would
654 	deadlock in the cases (beginning of sys_rename itself)
655 	in which we already have the sb rename sem */
656 	page = alloc_dentry_path();
657 	full_path = build_path_from_dentry(direntry, page);
658 	if (IS_ERR(full_path)) {
659 		cifs_put_tlink(tlink);
660 		free_xid(xid);
661 		free_dentry_path(page);
662 		return ERR_CAST(full_path);
663 	}
664 
665 	if (d_really_is_positive(direntry)) {
666 		cifs_dbg(FYI, "non-NULL inode in lookup\n");
667 	} else {
668 		cifs_dbg(FYI, "NULL inode in lookup\n");
669 	}
670 	cifs_dbg(FYI, "Full path: %s inode = 0x%p\n",
671 		 full_path, d_inode(direntry));
672 
673 again:
674 	if (pTcon->posix_extensions)
675 		rc = smb311_posix_get_inode_info(&newInode, full_path, parent_dir_inode->i_sb, xid);
676 	else if (pTcon->unix_ext) {
677 		rc = cifs_get_inode_info_unix(&newInode, full_path,
678 					      parent_dir_inode->i_sb, xid);
679 	} else {
680 		rc = cifs_get_inode_info(&newInode, full_path, NULL,
681 				parent_dir_inode->i_sb, xid, NULL);
682 	}
683 
684 	if (rc == 0) {
685 		/* since paths are not looked up by component - the parent
686 		   directories are presumed to be good here */
687 		renew_parental_timestamps(direntry);
688 	} else if (rc == -EAGAIN && retry_count++ < 10) {
689 		goto again;
690 	} else if (rc == -ENOENT) {
691 		cifs_set_time(direntry, jiffies);
692 		newInode = NULL;
693 	} else {
694 		if (rc != -EACCES) {
695 			cifs_dbg(FYI, "Unexpected lookup error %d\n", rc);
696 			/* We special case check for Access Denied - since that
697 			is a common return code */
698 		}
699 		newInode = ERR_PTR(rc);
700 	}
701 	free_dentry_path(page);
702 	cifs_put_tlink(tlink);
703 	free_xid(xid);
704 	return d_splice_alias(newInode, direntry);
705 }
706 
707 static int
708 cifs_d_revalidate(struct dentry *direntry, unsigned int flags)
709 {
710 	struct inode *inode;
711 	int rc;
712 
713 	if (flags & LOOKUP_RCU)
714 		return -ECHILD;
715 
716 	if (d_really_is_positive(direntry)) {
717 		inode = d_inode(direntry);
718 		if ((flags & LOOKUP_REVAL) && !CIFS_CACHE_READ(CIFS_I(inode)))
719 			CIFS_I(inode)->time = 0; /* force reval */
720 
721 		rc = cifs_revalidate_dentry(direntry);
722 		if (rc) {
723 			cifs_dbg(FYI, "cifs_revalidate_dentry failed with rc=%d", rc);
724 			switch (rc) {
725 			case -ENOENT:
726 			case -ESTALE:
727 				/*
728 				 * Those errors mean the dentry is invalid
729 				 * (file was deleted or recreated)
730 				 */
731 				return 0;
732 			default:
733 				/*
734 				 * Otherwise some unexpected error happened
735 				 * report it as-is to VFS layer
736 				 */
737 				return rc;
738 			}
739 		}
740 		else {
741 			/*
742 			 * If the inode wasn't known to be a dfs entry when
743 			 * the dentry was instantiated, such as when created
744 			 * via ->readdir(), it needs to be set now since the
745 			 * attributes will have been updated by
746 			 * cifs_revalidate_dentry().
747 			 */
748 			if (IS_AUTOMOUNT(inode) &&
749 			   !(direntry->d_flags & DCACHE_NEED_AUTOMOUNT)) {
750 				spin_lock(&direntry->d_lock);
751 				direntry->d_flags |= DCACHE_NEED_AUTOMOUNT;
752 				spin_unlock(&direntry->d_lock);
753 			}
754 
755 			return 1;
756 		}
757 	}
758 
759 	/*
760 	 * This may be nfsd (or something), anyway, we can't see the
761 	 * intent of this. So, since this can be for creation, drop it.
762 	 */
763 	if (!flags)
764 		return 0;
765 
766 	/*
767 	 * Drop the negative dentry, in order to make sure to use the
768 	 * case sensitive name which is specified by user if this is
769 	 * for creation.
770 	 */
771 	if (flags & (LOOKUP_CREATE | LOOKUP_RENAME_TARGET))
772 		return 0;
773 
774 	if (time_after(jiffies, cifs_get_time(direntry) + HZ) || !lookupCacheEnabled)
775 		return 0;
776 
777 	return 1;
778 }
779 
780 /* static int cifs_d_delete(struct dentry *direntry)
781 {
782 	int rc = 0;
783 
784 	cifs_dbg(FYI, "In cifs d_delete, name = %pd\n", direntry);
785 
786 	return rc;
787 }     */
788 
789 const struct dentry_operations cifs_dentry_ops = {
790 	.d_revalidate = cifs_d_revalidate,
791 	.d_automount = cifs_dfs_d_automount,
792 /* d_delete:       cifs_d_delete,      */ /* not needed except for debugging */
793 };
794 
795 static int cifs_ci_hash(const struct dentry *dentry, struct qstr *q)
796 {
797 	struct nls_table *codepage = CIFS_SB(dentry->d_sb)->local_nls;
798 	unsigned long hash;
799 	wchar_t c;
800 	int i, charlen;
801 
802 	hash = init_name_hash(dentry);
803 	for (i = 0; i < q->len; i += charlen) {
804 		charlen = codepage->char2uni(&q->name[i], q->len - i, &c);
805 		/* error out if we can't convert the character */
806 		if (unlikely(charlen < 0))
807 			return charlen;
808 		hash = partial_name_hash(cifs_toupper(c), hash);
809 	}
810 	q->hash = end_name_hash(hash);
811 
812 	return 0;
813 }
814 
815 static int cifs_ci_compare(const struct dentry *dentry,
816 		unsigned int len, const char *str, const struct qstr *name)
817 {
818 	struct nls_table *codepage = CIFS_SB(dentry->d_sb)->local_nls;
819 	wchar_t c1, c2;
820 	int i, l1, l2;
821 
822 	/*
823 	 * We make the assumption here that uppercase characters in the local
824 	 * codepage are always the same length as their lowercase counterparts.
825 	 *
826 	 * If that's ever not the case, then this will fail to match it.
827 	 */
828 	if (name->len != len)
829 		return 1;
830 
831 	for (i = 0; i < len; i += l1) {
832 		/* Convert characters in both strings to UTF-16. */
833 		l1 = codepage->char2uni(&str[i], len - i, &c1);
834 		l2 = codepage->char2uni(&name->name[i], name->len - i, &c2);
835 
836 		/*
837 		 * If we can't convert either character, just declare it to
838 		 * be 1 byte long and compare the original byte.
839 		 */
840 		if (unlikely(l1 < 0 && l2 < 0)) {
841 			if (str[i] != name->name[i])
842 				return 1;
843 			l1 = 1;
844 			continue;
845 		}
846 
847 		/*
848 		 * Here, we again ass|u|me that upper/lowercase versions of
849 		 * a character are the same length in the local NLS.
850 		 */
851 		if (l1 != l2)
852 			return 1;
853 
854 		/* Now compare uppercase versions of these characters */
855 		if (cifs_toupper(c1) != cifs_toupper(c2))
856 			return 1;
857 	}
858 
859 	return 0;
860 }
861 
862 const struct dentry_operations cifs_ci_dentry_ops = {
863 	.d_revalidate = cifs_d_revalidate,
864 	.d_hash = cifs_ci_hash,
865 	.d_compare = cifs_ci_compare,
866 	.d_automount = cifs_dfs_d_automount,
867 };
868