xref: /linux/fs/smb/client/readdir.c (revision 4b132aacb0768ac1e652cf517097ea6f237214b9)
1 // SPDX-License-Identifier: LGPL-2.1
2 /*
3  *
4  *   Directory search handling
5  *
6  *   Copyright (C) International Business Machines  Corp., 2004, 2008
7  *   Copyright (C) Red Hat, Inc., 2011
8  *   Author(s): Steve French (sfrench@us.ibm.com)
9  *
10  */
11 #include <linux/fs.h>
12 #include <linux/pagemap.h>
13 #include <linux/slab.h>
14 #include <linux/stat.h>
15 #include "cifspdu.h"
16 #include "cifsglob.h"
17 #include "cifsproto.h"
18 #include "cifs_unicode.h"
19 #include "cifs_debug.h"
20 #include "cifs_fs_sb.h"
21 #include "cifsfs.h"
22 #include "smb2proto.h"
23 #include "fs_context.h"
24 #include "cached_dir.h"
25 #include "reparse.h"
26 
27 /*
28  * To be safe - for UCS to UTF-8 with strings loaded with the rare long
29  * characters alloc more to account for such multibyte target UTF-8
30  * characters.
31  */
32 #define UNICODE_NAME_MAX ((4 * NAME_MAX) + 2)
33 
34 #ifdef CONFIG_CIFS_DEBUG2
35 static void dump_cifs_file_struct(struct file *file, char *label)
36 {
37 	struct cifsFileInfo *cf;
38 
39 	if (file) {
40 		cf = file->private_data;
41 		if (cf == NULL) {
42 			cifs_dbg(FYI, "empty cifs private file data\n");
43 			return;
44 		}
45 		if (cf->invalidHandle)
46 			cifs_dbg(FYI, "Invalid handle\n");
47 		if (cf->srch_inf.endOfSearch)
48 			cifs_dbg(FYI, "end of search\n");
49 		if (cf->srch_inf.emptyDir)
50 			cifs_dbg(FYI, "empty dir\n");
51 	}
52 }
53 #else
54 static inline void dump_cifs_file_struct(struct file *file, char *label)
55 {
56 }
57 #endif /* DEBUG2 */
58 
59 /*
60  * Attempt to preload the dcache with the results from the FIND_FIRST/NEXT
61  *
62  * Find the dentry that matches "name". If there isn't one, create one. If it's
63  * a negative dentry or the uniqueid or filetype(mode) changed,
64  * then drop it and recreate it.
65  */
66 static void
67 cifs_prime_dcache(struct dentry *parent, struct qstr *name,
68 		    struct cifs_fattr *fattr)
69 {
70 	struct dentry *dentry, *alias;
71 	struct inode *inode;
72 	struct super_block *sb = parent->d_sb;
73 	struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
74 	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
75 	int rc;
76 
77 	cifs_dbg(FYI, "%s: for %s\n", __func__, name->name);
78 
79 	dentry = d_hash_and_lookup(parent, name);
80 	if (!dentry) {
81 		/*
82 		 * If we know that the inode will need to be revalidated
83 		 * immediately, then don't create a new dentry for it.
84 		 * We'll end up doing an on the wire call either way and
85 		 * this spares us an invalidation.
86 		 */
87 retry:
88 		if ((fattr->cf_cifsattrs & ATTR_REPARSE) ||
89 		    (fattr->cf_flags & CIFS_FATTR_NEED_REVAL))
90 			return;
91 
92 		dentry = d_alloc_parallel(parent, name, &wq);
93 	}
94 	if (IS_ERR(dentry))
95 		return;
96 	if (!d_in_lookup(dentry)) {
97 		inode = d_inode(dentry);
98 		if (inode) {
99 			if (d_mountpoint(dentry)) {
100 				dput(dentry);
101 				return;
102 			}
103 			/*
104 			 * If we're generating inode numbers, then we don't
105 			 * want to clobber the existing one with the one that
106 			 * the readdir code created.
107 			 */
108 			if (!(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM))
109 				fattr->cf_uniqueid = CIFS_I(inode)->uniqueid;
110 
111 			/*
112 			 * Update inode in place if both i_ino and i_mode didn't
113 			 * change.
114 			 */
115 			if (CIFS_I(inode)->uniqueid == fattr->cf_uniqueid) {
116 				/*
117 				 * Query dir responses don't provide enough
118 				 * information about reparse points other than
119 				 * their reparse tags.  Save an invalidation by
120 				 * not clobbering some existing attributes when
121 				 * reparse tag and ctime haven't changed.
122 				 */
123 				rc = 0;
124 				if (fattr->cf_cifsattrs & ATTR_REPARSE) {
125 					if (likely(reparse_inode_match(inode, fattr))) {
126 						fattr->cf_mode = inode->i_mode;
127 						fattr->cf_rdev = inode->i_rdev;
128 						fattr->cf_uid = inode->i_uid;
129 						fattr->cf_gid = inode->i_gid;
130 						fattr->cf_eof = CIFS_I(inode)->netfs.remote_i_size;
131 						fattr->cf_symlink_target = NULL;
132 					} else {
133 						CIFS_I(inode)->time = 0;
134 						rc = -ESTALE;
135 					}
136 				}
137 				if (!rc && !cifs_fattr_to_inode(inode, fattr, true)) {
138 					dput(dentry);
139 					return;
140 				}
141 			}
142 		}
143 		d_invalidate(dentry);
144 		dput(dentry);
145 		goto retry;
146 	} else {
147 		inode = cifs_iget(sb, fattr);
148 		if (!inode)
149 			inode = ERR_PTR(-ENOMEM);
150 		alias = d_splice_alias(inode, dentry);
151 		d_lookup_done(dentry);
152 		if (alias && !IS_ERR(alias))
153 			dput(alias);
154 	}
155 	dput(dentry);
156 }
157 
158 static void
159 cifs_fill_common_info(struct cifs_fattr *fattr, struct cifs_sb_info *cifs_sb)
160 {
161 	struct cifs_open_info_data data = {
162 		.reparse = { .tag = fattr->cf_cifstag, },
163 	};
164 
165 	fattr->cf_uid = cifs_sb->ctx->linux_uid;
166 	fattr->cf_gid = cifs_sb->ctx->linux_gid;
167 
168 	/*
169 	 * The IO_REPARSE_TAG_LX_ tags originally were used by WSL but they
170 	 * are preferred by the Linux client in some cases since, unlike
171 	 * the NFS reparse tag (or EAs), they don't require an extra query
172 	 * to determine which type of special file they represent.
173 	 * TODO: go through all documented  reparse tags to see if we can
174 	 * reasonably map some of them to directories vs. files vs. symlinks
175 	 */
176 	if ((fattr->cf_cifsattrs & ATTR_REPARSE) &&
177 	    cifs_reparse_point_to_fattr(cifs_sb, fattr, &data))
178 		goto out_reparse;
179 
180 	if (fattr->cf_cifsattrs & ATTR_DIRECTORY) {
181 		fattr->cf_mode = S_IFDIR | cifs_sb->ctx->dir_mode;
182 		fattr->cf_dtype = DT_DIR;
183 	} else {
184 		fattr->cf_mode = S_IFREG | cifs_sb->ctx->file_mode;
185 		fattr->cf_dtype = DT_REG;
186 	}
187 
188 out_reparse:
189 	/* non-unix readdir doesn't provide nlink */
190 	fattr->cf_flags |= CIFS_FATTR_UNKNOWN_NLINK;
191 
192 	if (fattr->cf_cifsattrs & ATTR_READONLY)
193 		fattr->cf_mode &= ~S_IWUGO;
194 
195 	/*
196 	 * We of course don't get ACL info in FIND_FIRST/NEXT results, so
197 	 * mark it for revalidation so that "ls -l" will look right. It might
198 	 * be super-slow, but if we don't do this then the ownership of files
199 	 * may look wrong since the inodes may not have timed out by the time
200 	 * "ls" does a stat() call on them.
201 	 */
202 	if ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_ACL) ||
203 	    (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MODE_FROM_SID))
204 		fattr->cf_flags |= CIFS_FATTR_NEED_REVAL;
205 
206 	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_UNX_EMUL &&
207 	    fattr->cf_cifsattrs & ATTR_SYSTEM) {
208 		if (fattr->cf_eof == 0)  {
209 			fattr->cf_mode &= ~S_IFMT;
210 			fattr->cf_mode |= S_IFIFO;
211 			fattr->cf_dtype = DT_FIFO;
212 		} else {
213 			/*
214 			 * trying to get the type and mode via SFU can be slow,
215 			 * so just call those regular files for now, and mark
216 			 * for reval
217 			 */
218 			fattr->cf_flags |= CIFS_FATTR_NEED_REVAL;
219 		}
220 	}
221 }
222 
223 /* Fill a cifs_fattr struct with info from SMB_FIND_FILE_POSIX_INFO. */
224 static void
225 cifs_posix_to_fattr(struct cifs_fattr *fattr, struct smb2_posix_info *info,
226 		    struct cifs_sb_info *cifs_sb)
227 {
228 	struct smb2_posix_info_parsed parsed;
229 
230 	posix_info_parse(info, NULL, &parsed);
231 
232 	memset(fattr, 0, sizeof(*fattr));
233 	fattr->cf_uniqueid = le64_to_cpu(info->Inode);
234 	fattr->cf_bytes = le64_to_cpu(info->AllocationSize);
235 	fattr->cf_eof = le64_to_cpu(info->EndOfFile);
236 
237 	fattr->cf_atime = cifs_NTtimeToUnix(info->LastAccessTime);
238 	fattr->cf_mtime = cifs_NTtimeToUnix(info->LastWriteTime);
239 	fattr->cf_ctime = cifs_NTtimeToUnix(info->CreationTime);
240 
241 	fattr->cf_nlink = le32_to_cpu(info->HardLinks);
242 	fattr->cf_cifsattrs = le32_to_cpu(info->DosAttributes);
243 
244 	/*
245 	 * Since we set the inode type below we need to mask off
246 	 * to avoid strange results if bits set above.
247 	 * XXX: why not make server&client use the type bits?
248 	 */
249 	fattr->cf_mode = le32_to_cpu(info->Mode) & ~S_IFMT;
250 
251 	cifs_dbg(FYI, "posix fattr: dev %d, reparse %d, mode %o\n",
252 		 le32_to_cpu(info->DeviceId),
253 		 le32_to_cpu(info->ReparseTag),
254 		 le32_to_cpu(info->Mode));
255 
256 	if (fattr->cf_cifsattrs & ATTR_DIRECTORY) {
257 		fattr->cf_mode |= S_IFDIR;
258 		fattr->cf_dtype = DT_DIR;
259 	} else {
260 		/*
261 		 * mark anything that is not a dir as regular
262 		 * file. special files should have the REPARSE
263 		 * attribute and will be marked as needing revaluation
264 		 */
265 		fattr->cf_mode |= S_IFREG;
266 		fattr->cf_dtype = DT_REG;
267 	}
268 
269 	sid_to_id(cifs_sb, &parsed.owner, fattr, SIDOWNER);
270 	sid_to_id(cifs_sb, &parsed.group, fattr, SIDGROUP);
271 }
272 
273 static void __dir_info_to_fattr(struct cifs_fattr *fattr, const void *info)
274 {
275 	const FILE_DIRECTORY_INFO *fi = info;
276 
277 	memset(fattr, 0, sizeof(*fattr));
278 	fattr->cf_cifsattrs = le32_to_cpu(fi->ExtFileAttributes);
279 	fattr->cf_eof = le64_to_cpu(fi->EndOfFile);
280 	fattr->cf_bytes = le64_to_cpu(fi->AllocationSize);
281 	fattr->cf_createtime = le64_to_cpu(fi->CreationTime);
282 	fattr->cf_atime = cifs_NTtimeToUnix(fi->LastAccessTime);
283 	fattr->cf_ctime = cifs_NTtimeToUnix(fi->ChangeTime);
284 	fattr->cf_mtime = cifs_NTtimeToUnix(fi->LastWriteTime);
285 }
286 
287 void
288 cifs_dir_info_to_fattr(struct cifs_fattr *fattr, FILE_DIRECTORY_INFO *info,
289 		       struct cifs_sb_info *cifs_sb)
290 {
291 	__dir_info_to_fattr(fattr, info);
292 	cifs_fill_common_info(fattr, cifs_sb);
293 }
294 
295 static void cifs_fulldir_info_to_fattr(struct cifs_fattr *fattr,
296 				       const void *info,
297 				       struct cifs_sb_info *cifs_sb)
298 {
299 	const FILE_FULL_DIRECTORY_INFO *di = info;
300 
301 	__dir_info_to_fattr(fattr, info);
302 
303 	/* See MS-FSCC 2.4.14, 2.4.19 */
304 	if (fattr->cf_cifsattrs & ATTR_REPARSE)
305 		fattr->cf_cifstag = le32_to_cpu(di->EaSize);
306 	cifs_fill_common_info(fattr, cifs_sb);
307 }
308 
309 static void
310 cifs_std_info_to_fattr(struct cifs_fattr *fattr, FIND_FILE_STANDARD_INFO *info,
311 		       struct cifs_sb_info *cifs_sb)
312 {
313 	int offset = cifs_sb_master_tcon(cifs_sb)->ses->server->timeAdj;
314 
315 	memset(fattr, 0, sizeof(*fattr));
316 	fattr->cf_atime = cnvrtDosUnixTm(info->LastAccessDate,
317 					    info->LastAccessTime, offset);
318 	fattr->cf_ctime = cnvrtDosUnixTm(info->LastWriteDate,
319 					    info->LastWriteTime, offset);
320 	fattr->cf_mtime = cnvrtDosUnixTm(info->LastWriteDate,
321 					    info->LastWriteTime, offset);
322 
323 	fattr->cf_cifsattrs = le16_to_cpu(info->Attributes);
324 	fattr->cf_bytes = le32_to_cpu(info->AllocationSize);
325 	fattr->cf_eof = le32_to_cpu(info->DataSize);
326 
327 	cifs_fill_common_info(fattr, cifs_sb);
328 }
329 
330 static int
331 _initiate_cifs_search(const unsigned int xid, struct file *file,
332 		     const char *full_path)
333 {
334 	__u16 search_flags;
335 	int rc = 0;
336 	struct cifsFileInfo *cifsFile;
337 	struct cifs_sb_info *cifs_sb = CIFS_FILE_SB(file);
338 	struct tcon_link *tlink = NULL;
339 	struct cifs_tcon *tcon;
340 	struct TCP_Server_Info *server;
341 
342 	if (file->private_data == NULL) {
343 		tlink = cifs_sb_tlink(cifs_sb);
344 		if (IS_ERR(tlink))
345 			return PTR_ERR(tlink);
346 
347 		cifsFile = kzalloc(sizeof(struct cifsFileInfo), GFP_KERNEL);
348 		if (cifsFile == NULL) {
349 			rc = -ENOMEM;
350 			goto error_exit;
351 		}
352 		spin_lock_init(&cifsFile->file_info_lock);
353 		file->private_data = cifsFile;
354 		cifsFile->tlink = cifs_get_tlink(tlink);
355 		tcon = tlink_tcon(tlink);
356 	} else {
357 		cifsFile = file->private_data;
358 		tcon = tlink_tcon(cifsFile->tlink);
359 	}
360 
361 	server = tcon->ses->server;
362 
363 	if (!server->ops->query_dir_first) {
364 		rc = -ENOSYS;
365 		goto error_exit;
366 	}
367 
368 	cifsFile->invalidHandle = true;
369 	cifsFile->srch_inf.endOfSearch = false;
370 
371 	cifs_dbg(FYI, "Full path: %s start at: %lld\n", full_path, file->f_pos);
372 
373 ffirst_retry:
374 	/* test for Unix extensions */
375 	/* but now check for them on the share/mount not on the SMB session */
376 	/* if (cap_unix(tcon->ses) { */
377 	if (tcon->unix_ext)
378 		cifsFile->srch_inf.info_level = SMB_FIND_FILE_UNIX;
379 	else if (tcon->posix_extensions)
380 		cifsFile->srch_inf.info_level = SMB_FIND_FILE_POSIX_INFO;
381 	else if ((tcon->ses->capabilities &
382 		  tcon->ses->server->vals->cap_nt_find) == 0) {
383 		cifsFile->srch_inf.info_level = SMB_FIND_FILE_INFO_STANDARD;
384 	} else if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM) {
385 		cifsFile->srch_inf.info_level = SMB_FIND_FILE_ID_FULL_DIR_INFO;
386 	} else /* not srvinos - BB fixme add check for backlevel? */ {
387 		cifsFile->srch_inf.info_level = SMB_FIND_FILE_FULL_DIRECTORY_INFO;
388 	}
389 
390 	search_flags = CIFS_SEARCH_CLOSE_AT_END | CIFS_SEARCH_RETURN_RESUME;
391 	if (backup_cred(cifs_sb))
392 		search_flags |= CIFS_SEARCH_BACKUP_SEARCH;
393 
394 	rc = server->ops->query_dir_first(xid, tcon, full_path, cifs_sb,
395 					  &cifsFile->fid, search_flags,
396 					  &cifsFile->srch_inf);
397 
398 	if (rc == 0) {
399 		cifsFile->invalidHandle = false;
400 	} else if ((rc == -EOPNOTSUPP) &&
401 		   (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM)) {
402 		cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_SERVER_INUM;
403 		goto ffirst_retry;
404 	}
405 error_exit:
406 	cifs_put_tlink(tlink);
407 	return rc;
408 }
409 
410 static int
411 initiate_cifs_search(const unsigned int xid, struct file *file,
412 		     const char *full_path)
413 {
414 	int rc, retry_count = 0;
415 
416 	do {
417 		rc = _initiate_cifs_search(xid, file, full_path);
418 		/*
419 		 * If we don't have enough credits to start reading the
420 		 * directory just try again after short wait.
421 		 */
422 		if (rc != -EDEADLK)
423 			break;
424 
425 		usleep_range(512, 2048);
426 	} while (retry_count++ < 5);
427 
428 	return rc;
429 }
430 
431 /* return length of unicode string in bytes */
432 static int cifs_unicode_bytelen(const char *str)
433 {
434 	int len;
435 	const __le16 *ustr = (const __le16 *)str;
436 
437 	for (len = 0; len <= PATH_MAX; len++) {
438 		if (ustr[len] == 0)
439 			return len << 1;
440 	}
441 	cifs_dbg(FYI, "Unicode string longer than PATH_MAX found\n");
442 	return len << 1;
443 }
444 
445 static char *nxt_dir_entry(char *old_entry, char *end_of_smb, int level)
446 {
447 	char *new_entry;
448 	FILE_DIRECTORY_INFO *pDirInfo = (FILE_DIRECTORY_INFO *)old_entry;
449 
450 	if (level == SMB_FIND_FILE_INFO_STANDARD) {
451 		FIND_FILE_STANDARD_INFO *pfData;
452 		pfData = (FIND_FILE_STANDARD_INFO *)pDirInfo;
453 
454 		new_entry = old_entry + sizeof(FIND_FILE_STANDARD_INFO) + 1 +
455 				pfData->FileNameLength;
456 	} else {
457 		u32 next_offset = le32_to_cpu(pDirInfo->NextEntryOffset);
458 
459 		if (old_entry + next_offset < old_entry) {
460 			cifs_dbg(VFS, "Invalid offset %u\n", next_offset);
461 			return NULL;
462 		}
463 		new_entry = old_entry + next_offset;
464 	}
465 	cifs_dbg(FYI, "new entry %p old entry %p\n", new_entry, old_entry);
466 	/* validate that new_entry is not past end of SMB */
467 	if (new_entry >= end_of_smb) {
468 		cifs_dbg(VFS, "search entry %p began after end of SMB %p old entry %p\n",
469 			 new_entry, end_of_smb, old_entry);
470 		return NULL;
471 	} else if (((level == SMB_FIND_FILE_INFO_STANDARD) &&
472 		    (new_entry + sizeof(FIND_FILE_STANDARD_INFO) + 1 > end_of_smb))
473 		  || ((level != SMB_FIND_FILE_INFO_STANDARD) &&
474 		   (new_entry + sizeof(FILE_DIRECTORY_INFO) + 1 > end_of_smb)))  {
475 		cifs_dbg(VFS, "search entry %p extends after end of SMB %p\n",
476 			 new_entry, end_of_smb);
477 		return NULL;
478 	} else
479 		return new_entry;
480 
481 }
482 
483 struct cifs_dirent {
484 	const char	*name;
485 	size_t		namelen;
486 	u32		resume_key;
487 	u64		ino;
488 };
489 
490 static void cifs_fill_dirent_posix(struct cifs_dirent *de,
491 				   const struct smb2_posix_info *info)
492 {
493 	struct smb2_posix_info_parsed parsed;
494 
495 	/* payload should have already been checked at this point */
496 	if (posix_info_parse(info, NULL, &parsed) < 0) {
497 		cifs_dbg(VFS, "Invalid POSIX info payload\n");
498 		return;
499 	}
500 
501 	de->name = parsed.name;
502 	de->namelen = parsed.name_len;
503 	de->resume_key = info->Ignored;
504 	de->ino = le64_to_cpu(info->Inode);
505 }
506 
507 static void cifs_fill_dirent_unix(struct cifs_dirent *de,
508 		const FILE_UNIX_INFO *info, bool is_unicode)
509 {
510 	de->name = &info->FileName[0];
511 	if (is_unicode)
512 		de->namelen = cifs_unicode_bytelen(de->name);
513 	else
514 		de->namelen = strnlen(de->name, PATH_MAX);
515 	de->resume_key = info->ResumeKey;
516 	de->ino = le64_to_cpu(info->basic.UniqueId);
517 }
518 
519 static void cifs_fill_dirent_dir(struct cifs_dirent *de,
520 		const FILE_DIRECTORY_INFO *info)
521 {
522 	de->name = &info->FileName[0];
523 	de->namelen = le32_to_cpu(info->FileNameLength);
524 	de->resume_key = info->FileIndex;
525 }
526 
527 static void cifs_fill_dirent_full(struct cifs_dirent *de,
528 		const FILE_FULL_DIRECTORY_INFO *info)
529 {
530 	de->name = &info->FileName[0];
531 	de->namelen = le32_to_cpu(info->FileNameLength);
532 	de->resume_key = info->FileIndex;
533 }
534 
535 static void cifs_fill_dirent_search(struct cifs_dirent *de,
536 		const SEARCH_ID_FULL_DIR_INFO *info)
537 {
538 	de->name = &info->FileName[0];
539 	de->namelen = le32_to_cpu(info->FileNameLength);
540 	de->resume_key = info->FileIndex;
541 	de->ino = le64_to_cpu(info->UniqueId);
542 }
543 
544 static void cifs_fill_dirent_both(struct cifs_dirent *de,
545 		const FILE_BOTH_DIRECTORY_INFO *info)
546 {
547 	de->name = &info->FileName[0];
548 	de->namelen = le32_to_cpu(info->FileNameLength);
549 	de->resume_key = info->FileIndex;
550 }
551 
552 static void cifs_fill_dirent_std(struct cifs_dirent *de,
553 		const FIND_FILE_STANDARD_INFO *info)
554 {
555 	de->name = &info->FileName[0];
556 	/* one byte length, no endianess conversion */
557 	de->namelen = info->FileNameLength;
558 	de->resume_key = info->ResumeKey;
559 }
560 
561 static int cifs_fill_dirent(struct cifs_dirent *de, const void *info,
562 		u16 level, bool is_unicode)
563 {
564 	memset(de, 0, sizeof(*de));
565 
566 	switch (level) {
567 	case SMB_FIND_FILE_POSIX_INFO:
568 		cifs_fill_dirent_posix(de, info);
569 		break;
570 	case SMB_FIND_FILE_UNIX:
571 		cifs_fill_dirent_unix(de, info, is_unicode);
572 		break;
573 	case SMB_FIND_FILE_DIRECTORY_INFO:
574 		cifs_fill_dirent_dir(de, info);
575 		break;
576 	case SMB_FIND_FILE_FULL_DIRECTORY_INFO:
577 		cifs_fill_dirent_full(de, info);
578 		break;
579 	case SMB_FIND_FILE_ID_FULL_DIR_INFO:
580 		cifs_fill_dirent_search(de, info);
581 		break;
582 	case SMB_FIND_FILE_BOTH_DIRECTORY_INFO:
583 		cifs_fill_dirent_both(de, info);
584 		break;
585 	case SMB_FIND_FILE_INFO_STANDARD:
586 		cifs_fill_dirent_std(de, info);
587 		break;
588 	default:
589 		cifs_dbg(FYI, "Unknown findfirst level %d\n", level);
590 		return -EINVAL;
591 	}
592 
593 	return 0;
594 }
595 
596 #define UNICODE_DOT cpu_to_le16(0x2e)
597 
598 /* return 0 if no match and 1 for . (current directory) and 2 for .. (parent) */
599 static int cifs_entry_is_dot(struct cifs_dirent *de, bool is_unicode)
600 {
601 	int rc = 0;
602 
603 	if (!de->name)
604 		return 0;
605 
606 	if (is_unicode) {
607 		__le16 *ufilename = (__le16 *)de->name;
608 		if (de->namelen == 2) {
609 			/* check for . */
610 			if (ufilename[0] == UNICODE_DOT)
611 				rc = 1;
612 		} else if (de->namelen == 4) {
613 			/* check for .. */
614 			if (ufilename[0] == UNICODE_DOT &&
615 			    ufilename[1] == UNICODE_DOT)
616 				rc = 2;
617 		}
618 	} else /* ASCII */ {
619 		if (de->namelen == 1) {
620 			if (de->name[0] == '.')
621 				rc = 1;
622 		} else if (de->namelen == 2) {
623 			if (de->name[0] == '.' && de->name[1] == '.')
624 				rc = 2;
625 		}
626 	}
627 
628 	return rc;
629 }
630 
631 /* Check if directory that we are searching has changed so we can decide
632    whether we can use the cached search results from the previous search */
633 static int is_dir_changed(struct file *file)
634 {
635 	struct inode *inode = file_inode(file);
636 	struct cifsInodeInfo *cifs_inode_info = CIFS_I(inode);
637 
638 	if (cifs_inode_info->time == 0)
639 		return 1; /* directory was changed, e.g. unlink or new file */
640 	else
641 		return 0;
642 
643 }
644 
645 static int cifs_save_resume_key(const char *current_entry,
646 	struct cifsFileInfo *file_info)
647 {
648 	struct cifs_dirent de;
649 	int rc;
650 
651 	rc = cifs_fill_dirent(&de, current_entry, file_info->srch_inf.info_level,
652 			      file_info->srch_inf.unicode);
653 	if (!rc) {
654 		file_info->srch_inf.presume_name = de.name;
655 		file_info->srch_inf.resume_name_len = de.namelen;
656 		file_info->srch_inf.resume_key = de.resume_key;
657 	}
658 	return rc;
659 }
660 
661 /*
662  * Find the corresponding entry in the search. Note that the SMB server returns
663  * search entries for . and .. which complicates logic here if we choose to
664  * parse for them and we do not assume that they are located in the findfirst
665  * return buffer. We start counting in the buffer with entry 2 and increment for
666  * every entry (do not increment for . or .. entry).
667  */
668 static int
669 find_cifs_entry(const unsigned int xid, struct cifs_tcon *tcon, loff_t pos,
670 		struct file *file, const char *full_path,
671 		char **current_entry, int *num_to_ret)
672 {
673 	__u16 search_flags;
674 	int rc = 0;
675 	int pos_in_buf = 0;
676 	loff_t first_entry_in_buffer;
677 	loff_t index_to_find = pos;
678 	struct cifsFileInfo *cfile = file->private_data;
679 	struct cifs_sb_info *cifs_sb = CIFS_FILE_SB(file);
680 	struct TCP_Server_Info *server = tcon->ses->server;
681 	/* check if index in the buffer */
682 
683 	if (!server->ops->query_dir_first || !server->ops->query_dir_next)
684 		return -ENOSYS;
685 
686 	if ((cfile == NULL) || (current_entry == NULL) || (num_to_ret == NULL))
687 		return -ENOENT;
688 
689 	*current_entry = NULL;
690 	first_entry_in_buffer = cfile->srch_inf.index_of_last_entry -
691 					cfile->srch_inf.entries_in_buffer;
692 
693 	/*
694 	 * If first entry in buf is zero then is first buffer
695 	 * in search response data which means it is likely . and ..
696 	 * will be in this buffer, although some servers do not return
697 	 * . and .. for the root of a drive and for those we need
698 	 * to start two entries earlier.
699 	 */
700 
701 	dump_cifs_file_struct(file, "In fce ");
702 	if (((index_to_find < cfile->srch_inf.index_of_last_entry) &&
703 	     is_dir_changed(file)) || (index_to_find < first_entry_in_buffer)) {
704 		/* close and restart search */
705 		cifs_dbg(FYI, "search backing up - close and restart search\n");
706 		spin_lock(&cfile->file_info_lock);
707 		if (server->ops->dir_needs_close(cfile)) {
708 			cfile->invalidHandle = true;
709 			spin_unlock(&cfile->file_info_lock);
710 			if (server->ops->close_dir)
711 				server->ops->close_dir(xid, tcon, &cfile->fid);
712 		} else
713 			spin_unlock(&cfile->file_info_lock);
714 		if (cfile->srch_inf.ntwrk_buf_start) {
715 			cifs_dbg(FYI, "freeing SMB ff cache buf on search rewind\n");
716 			if (cfile->srch_inf.smallBuf)
717 				cifs_small_buf_release(cfile->srch_inf.
718 						ntwrk_buf_start);
719 			else
720 				cifs_buf_release(cfile->srch_inf.
721 						ntwrk_buf_start);
722 			cfile->srch_inf.ntwrk_buf_start = NULL;
723 		}
724 		rc = initiate_cifs_search(xid, file, full_path);
725 		if (rc) {
726 			cifs_dbg(FYI, "error %d reinitiating a search on rewind\n",
727 				 rc);
728 			return rc;
729 		}
730 		/* FindFirst/Next set last_entry to NULL on malformed reply */
731 		if (cfile->srch_inf.last_entry)
732 			cifs_save_resume_key(cfile->srch_inf.last_entry, cfile);
733 	}
734 
735 	search_flags = CIFS_SEARCH_CLOSE_AT_END | CIFS_SEARCH_RETURN_RESUME;
736 	if (backup_cred(cifs_sb))
737 		search_flags |= CIFS_SEARCH_BACKUP_SEARCH;
738 
739 	while ((index_to_find >= cfile->srch_inf.index_of_last_entry) &&
740 	       (rc == 0) && !cfile->srch_inf.endOfSearch) {
741 		cifs_dbg(FYI, "calling findnext2\n");
742 		rc = server->ops->query_dir_next(xid, tcon, &cfile->fid,
743 						 search_flags,
744 						 &cfile->srch_inf);
745 		/* FindFirst/Next set last_entry to NULL on malformed reply */
746 		if (cfile->srch_inf.last_entry)
747 			cifs_save_resume_key(cfile->srch_inf.last_entry, cfile);
748 		if (rc)
749 			return -ENOENT;
750 	}
751 	if (index_to_find < cfile->srch_inf.index_of_last_entry) {
752 		/* we found the buffer that contains the entry */
753 		/* scan and find it */
754 		int i;
755 		char *cur_ent;
756 		char *end_of_smb;
757 
758 		if (cfile->srch_inf.ntwrk_buf_start == NULL) {
759 			cifs_dbg(VFS, "ntwrk_buf_start is NULL during readdir\n");
760 			return -EIO;
761 		}
762 
763 		end_of_smb = cfile->srch_inf.ntwrk_buf_start +
764 			server->ops->calc_smb_size(
765 					cfile->srch_inf.ntwrk_buf_start);
766 
767 		cur_ent = cfile->srch_inf.srch_entries_start;
768 		first_entry_in_buffer = cfile->srch_inf.index_of_last_entry
769 					- cfile->srch_inf.entries_in_buffer;
770 		pos_in_buf = index_to_find - first_entry_in_buffer;
771 		cifs_dbg(FYI, "found entry - pos_in_buf %d\n", pos_in_buf);
772 
773 		for (i = 0; (i < (pos_in_buf)) && (cur_ent != NULL); i++) {
774 			/* go entry by entry figuring out which is first */
775 			cur_ent = nxt_dir_entry(cur_ent, end_of_smb,
776 						cfile->srch_inf.info_level);
777 		}
778 		if ((cur_ent == NULL) && (i < pos_in_buf)) {
779 			/* BB fixme - check if we should flag this error */
780 			cifs_dbg(VFS, "reached end of buf searching for pos in buf %d index to find %lld rc %d\n",
781 				 pos_in_buf, index_to_find, rc);
782 		}
783 		rc = 0;
784 		*current_entry = cur_ent;
785 	} else {
786 		cifs_dbg(FYI, "index not in buffer - could not findnext into it\n");
787 		return 0;
788 	}
789 
790 	if (pos_in_buf >= cfile->srch_inf.entries_in_buffer) {
791 		cifs_dbg(FYI, "can not return entries pos_in_buf beyond last\n");
792 		*num_to_ret = 0;
793 	} else
794 		*num_to_ret = cfile->srch_inf.entries_in_buffer - pos_in_buf;
795 
796 	return rc;
797 }
798 
799 static bool emit_cached_dirents(struct cached_dirents *cde,
800 				struct dir_context *ctx)
801 {
802 	struct cached_dirent *dirent;
803 	bool rc;
804 
805 	list_for_each_entry(dirent, &cde->entries, entry) {
806 		/*
807 		 * Skip all early entries prior to the current lseek()
808 		 * position.
809 		 */
810 		if (ctx->pos > dirent->pos)
811 			continue;
812 		/*
813 		 * We recorded the current ->pos value for the dirent
814 		 * when we stored it in the cache.
815 		 * However, this sequence of ->pos values may have holes
816 		 * in it, for example dot-dirs returned from the server
817 		 * are suppressed.
818 		 * Handle this bu forcing ctx->pos to be the same as the
819 		 * ->pos of the current dirent we emit from the cache.
820 		 * This means that when we emit these entries from the cache
821 		 * we now emit them with the same ->pos value as in the
822 		 * initial scan.
823 		 */
824 		ctx->pos = dirent->pos;
825 		rc = dir_emit(ctx, dirent->name, dirent->namelen,
826 			      dirent->fattr.cf_uniqueid,
827 			      dirent->fattr.cf_dtype);
828 		if (!rc)
829 			return rc;
830 		ctx->pos++;
831 	}
832 	return true;
833 }
834 
835 static void update_cached_dirents_count(struct cached_dirents *cde,
836 					struct dir_context *ctx)
837 {
838 	if (cde->ctx != ctx)
839 		return;
840 	if (cde->is_valid || cde->is_failed)
841 		return;
842 
843 	cde->pos++;
844 }
845 
846 static void finished_cached_dirents_count(struct cached_dirents *cde,
847 					struct dir_context *ctx)
848 {
849 	if (cde->ctx != ctx)
850 		return;
851 	if (cde->is_valid || cde->is_failed)
852 		return;
853 	if (ctx->pos != cde->pos)
854 		return;
855 
856 	cde->is_valid = 1;
857 }
858 
859 static void add_cached_dirent(struct cached_dirents *cde,
860 			      struct dir_context *ctx,
861 			      const char *name, int namelen,
862 			      struct cifs_fattr *fattr)
863 {
864 	struct cached_dirent *de;
865 
866 	if (cde->ctx != ctx)
867 		return;
868 	if (cde->is_valid || cde->is_failed)
869 		return;
870 	if (ctx->pos != cde->pos) {
871 		cde->is_failed = 1;
872 		return;
873 	}
874 	de = kzalloc(sizeof(*de), GFP_ATOMIC);
875 	if (de == NULL) {
876 		cde->is_failed = 1;
877 		return;
878 	}
879 	de->namelen = namelen;
880 	de->name = kstrndup(name, namelen, GFP_ATOMIC);
881 	if (de->name == NULL) {
882 		kfree(de);
883 		cde->is_failed = 1;
884 		return;
885 	}
886 	de->pos = ctx->pos;
887 
888 	memcpy(&de->fattr, fattr, sizeof(struct cifs_fattr));
889 
890 	list_add_tail(&de->entry, &cde->entries);
891 }
892 
893 static bool cifs_dir_emit(struct dir_context *ctx,
894 			  const char *name, int namelen,
895 			  struct cifs_fattr *fattr,
896 			  struct cached_fid *cfid)
897 {
898 	bool rc;
899 	ino_t ino = cifs_uniqueid_to_ino_t(fattr->cf_uniqueid);
900 
901 	rc = dir_emit(ctx, name, namelen, ino, fattr->cf_dtype);
902 	if (!rc)
903 		return rc;
904 
905 	if (cfid) {
906 		mutex_lock(&cfid->dirents.de_mutex);
907 		add_cached_dirent(&cfid->dirents, ctx, name, namelen,
908 				  fattr);
909 		mutex_unlock(&cfid->dirents.de_mutex);
910 	}
911 
912 	return rc;
913 }
914 
915 static int cifs_filldir(char *find_entry, struct file *file,
916 			struct dir_context *ctx,
917 			char *scratch_buf, unsigned int max_len,
918 			struct cached_fid *cfid)
919 {
920 	struct cifsFileInfo *file_info = file->private_data;
921 	struct super_block *sb = file_inode(file)->i_sb;
922 	struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
923 	struct cifs_dirent de = { NULL, };
924 	struct cifs_fattr fattr;
925 	struct qstr name;
926 	int rc = 0;
927 
928 	rc = cifs_fill_dirent(&de, find_entry, file_info->srch_inf.info_level,
929 			      file_info->srch_inf.unicode);
930 	if (rc)
931 		return rc;
932 
933 	if (de.namelen > max_len) {
934 		cifs_dbg(VFS, "bad search response length %zd past smb end\n",
935 			 de.namelen);
936 		return -EINVAL;
937 	}
938 
939 	/* skip . and .. since we added them first */
940 	if (cifs_entry_is_dot(&de, file_info->srch_inf.unicode))
941 		return 0;
942 
943 	if (file_info->srch_inf.unicode) {
944 		struct nls_table *nlt = cifs_sb->local_nls;
945 		int map_type;
946 
947 		map_type = cifs_remap(cifs_sb);
948 		name.name = scratch_buf;
949 		name.len =
950 			cifs_from_utf16((char *)name.name, (__le16 *)de.name,
951 					UNICODE_NAME_MAX,
952 					min_t(size_t, de.namelen,
953 					      (size_t)max_len), nlt, map_type);
954 		name.len -= nls_nullsize(nlt);
955 	} else {
956 		name.name = de.name;
957 		name.len = de.namelen;
958 	}
959 
960 	switch (file_info->srch_inf.info_level) {
961 	case SMB_FIND_FILE_POSIX_INFO:
962 		cifs_posix_to_fattr(&fattr,
963 				    (struct smb2_posix_info *)find_entry,
964 				    cifs_sb);
965 		break;
966 	case SMB_FIND_FILE_UNIX:
967 		cifs_unix_basic_to_fattr(&fattr,
968 					 &((FILE_UNIX_INFO *)find_entry)->basic,
969 					 cifs_sb);
970 		if (S_ISLNK(fattr.cf_mode))
971 			fattr.cf_flags |= CIFS_FATTR_NEED_REVAL;
972 		break;
973 	case SMB_FIND_FILE_INFO_STANDARD:
974 		cifs_std_info_to_fattr(&fattr,
975 				       (FIND_FILE_STANDARD_INFO *)find_entry,
976 				       cifs_sb);
977 		break;
978 	case SMB_FIND_FILE_FULL_DIRECTORY_INFO:
979 	case SMB_FIND_FILE_ID_FULL_DIR_INFO:
980 		cifs_fulldir_info_to_fattr(&fattr, find_entry, cifs_sb);
981 		break;
982 	default:
983 		cifs_dir_info_to_fattr(&fattr,
984 				       (FILE_DIRECTORY_INFO *)find_entry,
985 				       cifs_sb);
986 		break;
987 	}
988 
989 	if (de.ino && (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM)) {
990 		fattr.cf_uniqueid = de.ino;
991 	} else {
992 		fattr.cf_uniqueid = iunique(sb, ROOT_I);
993 		cifs_autodisable_serverino(cifs_sb);
994 	}
995 
996 	if ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS) &&
997 	    couldbe_mf_symlink(&fattr))
998 		/*
999 		 * trying to get the type and mode can be slow,
1000 		 * so just call those regular files for now, and mark
1001 		 * for reval
1002 		 */
1003 		fattr.cf_flags |= CIFS_FATTR_NEED_REVAL;
1004 
1005 	cifs_prime_dcache(file_dentry(file), &name, &fattr);
1006 
1007 	return !cifs_dir_emit(ctx, name.name, name.len,
1008 			      &fattr, cfid);
1009 }
1010 
1011 
1012 int cifs_readdir(struct file *file, struct dir_context *ctx)
1013 {
1014 	int rc = 0;
1015 	unsigned int xid;
1016 	int i;
1017 	struct tcon_link *tlink = NULL;
1018 	struct cifs_tcon *tcon;
1019 	struct cifsFileInfo *cifsFile;
1020 	char *current_entry;
1021 	int num_to_fill = 0;
1022 	char *tmp_buf = NULL;
1023 	char *end_of_smb;
1024 	unsigned int max_len;
1025 	const char *full_path;
1026 	void *page = alloc_dentry_path();
1027 	struct cached_fid *cfid = NULL;
1028 	struct cifs_sb_info *cifs_sb = CIFS_FILE_SB(file);
1029 
1030 	xid = get_xid();
1031 
1032 	full_path = build_path_from_dentry(file_dentry(file), page);
1033 	if (IS_ERR(full_path)) {
1034 		rc = PTR_ERR(full_path);
1035 		goto rddir2_exit;
1036 	}
1037 
1038 	if (file->private_data == NULL) {
1039 		tlink = cifs_sb_tlink(cifs_sb);
1040 		if (IS_ERR(tlink))
1041 			goto cache_not_found;
1042 		tcon = tlink_tcon(tlink);
1043 	} else {
1044 		cifsFile = file->private_data;
1045 		tcon = tlink_tcon(cifsFile->tlink);
1046 	}
1047 
1048 	rc = open_cached_dir(xid, tcon, full_path, cifs_sb, false, &cfid);
1049 	cifs_put_tlink(tlink);
1050 	if (rc)
1051 		goto cache_not_found;
1052 
1053 	mutex_lock(&cfid->dirents.de_mutex);
1054 	/*
1055 	 * If this was reading from the start of the directory
1056 	 * we need to initialize scanning and storing the
1057 	 * directory content.
1058 	 */
1059 	if (ctx->pos == 0 && cfid->dirents.ctx == NULL) {
1060 		cfid->dirents.ctx = ctx;
1061 		cfid->dirents.pos = 2;
1062 	}
1063 	/*
1064 	 * If we already have the entire directory cached then
1065 	 * we can just serve the cache.
1066 	 */
1067 	if (cfid->dirents.is_valid) {
1068 		if (!dir_emit_dots(file, ctx)) {
1069 			mutex_unlock(&cfid->dirents.de_mutex);
1070 			goto rddir2_exit;
1071 		}
1072 		emit_cached_dirents(&cfid->dirents, ctx);
1073 		mutex_unlock(&cfid->dirents.de_mutex);
1074 		goto rddir2_exit;
1075 	}
1076 	mutex_unlock(&cfid->dirents.de_mutex);
1077 
1078 	/* Drop the cache while calling initiate_cifs_search and
1079 	 * find_cifs_entry in case there will be reconnects during
1080 	 * query_directory.
1081 	 */
1082 	close_cached_dir(cfid);
1083 	cfid = NULL;
1084 
1085  cache_not_found:
1086 	/*
1087 	 * Ensure FindFirst doesn't fail before doing filldir() for '.' and
1088 	 * '..'. Otherwise we won't be able to notify VFS in case of failure.
1089 	 */
1090 	if (file->private_data == NULL) {
1091 		rc = initiate_cifs_search(xid, file, full_path);
1092 		cifs_dbg(FYI, "initiate cifs search rc %d\n", rc);
1093 		if (rc)
1094 			goto rddir2_exit;
1095 	}
1096 
1097 	if (!dir_emit_dots(file, ctx))
1098 		goto rddir2_exit;
1099 
1100 	/* 1) If search is active,
1101 		is in current search buffer?
1102 		if it before then restart search
1103 		if after then keep searching till find it */
1104 	cifsFile = file->private_data;
1105 	if (cifsFile->srch_inf.endOfSearch) {
1106 		if (cifsFile->srch_inf.emptyDir) {
1107 			cifs_dbg(FYI, "End of search, empty dir\n");
1108 			rc = 0;
1109 			goto rddir2_exit;
1110 		}
1111 	} /* else {
1112 		cifsFile->invalidHandle = true;
1113 		tcon->ses->server->close(xid, tcon, &cifsFile->fid);
1114 	} */
1115 
1116 	tcon = tlink_tcon(cifsFile->tlink);
1117 	rc = find_cifs_entry(xid, tcon, ctx->pos, file, full_path,
1118 			     &current_entry, &num_to_fill);
1119 	open_cached_dir(xid, tcon, full_path, cifs_sb, false, &cfid);
1120 	if (rc) {
1121 		cifs_dbg(FYI, "fce error %d\n", rc);
1122 		goto rddir2_exit;
1123 	} else if (current_entry != NULL) {
1124 		cifs_dbg(FYI, "entry %lld found\n", ctx->pos);
1125 	} else {
1126 		if (cfid) {
1127 			mutex_lock(&cfid->dirents.de_mutex);
1128 			finished_cached_dirents_count(&cfid->dirents, ctx);
1129 			mutex_unlock(&cfid->dirents.de_mutex);
1130 		}
1131 		cifs_dbg(FYI, "Could not find entry\n");
1132 		goto rddir2_exit;
1133 	}
1134 	cifs_dbg(FYI, "loop through %d times filling dir for net buf %p\n",
1135 		 num_to_fill, cifsFile->srch_inf.ntwrk_buf_start);
1136 	max_len = tcon->ses->server->ops->calc_smb_size(
1137 			cifsFile->srch_inf.ntwrk_buf_start);
1138 	end_of_smb = cifsFile->srch_inf.ntwrk_buf_start + max_len;
1139 
1140 	tmp_buf = kmalloc(UNICODE_NAME_MAX, GFP_KERNEL);
1141 	if (tmp_buf == NULL) {
1142 		rc = -ENOMEM;
1143 		goto rddir2_exit;
1144 	}
1145 
1146 	for (i = 0; i < num_to_fill; i++) {
1147 		if (current_entry == NULL) {
1148 			/* evaluate whether this case is an error */
1149 			cifs_dbg(VFS, "past SMB end,  num to fill %d i %d\n",
1150 				 num_to_fill, i);
1151 			break;
1152 		}
1153 		/*
1154 		 * if buggy server returns . and .. late do we want to
1155 		 * check for that here?
1156 		 */
1157 		*tmp_buf = 0;
1158 		rc = cifs_filldir(current_entry, file, ctx,
1159 				  tmp_buf, max_len, cfid);
1160 		if (rc) {
1161 			if (rc > 0)
1162 				rc = 0;
1163 			break;
1164 		}
1165 
1166 		ctx->pos++;
1167 		if (cfid) {
1168 			mutex_lock(&cfid->dirents.de_mutex);
1169 			update_cached_dirents_count(&cfid->dirents, ctx);
1170 			mutex_unlock(&cfid->dirents.de_mutex);
1171 		}
1172 
1173 		if (ctx->pos ==
1174 			cifsFile->srch_inf.index_of_last_entry) {
1175 			cifs_dbg(FYI, "last entry in buf at pos %lld %s\n",
1176 				 ctx->pos, tmp_buf);
1177 			cifs_save_resume_key(current_entry, cifsFile);
1178 			break;
1179 		}
1180 		current_entry =
1181 			nxt_dir_entry(current_entry, end_of_smb,
1182 				      cifsFile->srch_inf.info_level);
1183 	}
1184 	kfree(tmp_buf);
1185 
1186 rddir2_exit:
1187 	if (cfid)
1188 		close_cached_dir(cfid);
1189 	free_dentry_path(page);
1190 	free_xid(xid);
1191 	return rc;
1192 }
1193