xref: /kernel/linux/linux-5.10/fs/cifs/readdir.c (revision 8c2ecf20)
1/*
2 *   fs/cifs/readdir.c
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 *   This library is free software; you can redistribute it and/or modify
11 *   it under the terms of the GNU Lesser General Public License as published
12 *   by the Free Software Foundation; either version 2.1 of the License, or
13 *   (at your option) any later version.
14 *
15 *   This library is distributed in the hope that it will be useful,
16 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
17 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
18 *   the GNU Lesser General Public License for more details.
19 *
20 *   You should have received a copy of the GNU Lesser General Public License
21 *   along with this library; if not, write to the Free Software
22 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
23 */
24#include <linux/fs.h>
25#include <linux/pagemap.h>
26#include <linux/slab.h>
27#include <linux/stat.h>
28#include "cifspdu.h"
29#include "cifsglob.h"
30#include "cifsproto.h"
31#include "cifs_unicode.h"
32#include "cifs_debug.h"
33#include "cifs_fs_sb.h"
34#include "cifsfs.h"
35#include "smb2proto.h"
36
37/*
38 * To be safe - for UCS to UTF-8 with strings loaded with the rare long
39 * characters alloc more to account for such multibyte target UTF-8
40 * characters.
41 */
42#define UNICODE_NAME_MAX ((4 * NAME_MAX) + 2)
43
44#ifdef CONFIG_CIFS_DEBUG2
45static void dump_cifs_file_struct(struct file *file, char *label)
46{
47	struct cifsFileInfo *cf;
48
49	if (file) {
50		cf = file->private_data;
51		if (cf == NULL) {
52			cifs_dbg(FYI, "empty cifs private file data\n");
53			return;
54		}
55		if (cf->invalidHandle)
56			cifs_dbg(FYI, "Invalid handle\n");
57		if (cf->srch_inf.endOfSearch)
58			cifs_dbg(FYI, "end of search\n");
59		if (cf->srch_inf.emptyDir)
60			cifs_dbg(FYI, "empty dir\n");
61	}
62}
63#else
64static inline void dump_cifs_file_struct(struct file *file, char *label)
65{
66}
67#endif /* DEBUG2 */
68
69/*
70 * Attempt to preload the dcache with the results from the FIND_FIRST/NEXT
71 *
72 * Find the dentry that matches "name". If there isn't one, create one. If it's
73 * a negative dentry or the uniqueid or filetype(mode) changed,
74 * then drop it and recreate it.
75 */
76static void
77cifs_prime_dcache(struct dentry *parent, struct qstr *name,
78		    struct cifs_fattr *fattr)
79{
80	struct dentry *dentry, *alias;
81	struct inode *inode;
82	struct super_block *sb = parent->d_sb;
83	struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
84	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
85
86	cifs_dbg(FYI, "%s: for %s\n", __func__, name->name);
87
88	dentry = d_hash_and_lookup(parent, name);
89	if (!dentry) {
90		/*
91		 * If we know that the inode will need to be revalidated
92		 * immediately, then don't create a new dentry for it.
93		 * We'll end up doing an on the wire call either way and
94		 * this spares us an invalidation.
95		 */
96		if (fattr->cf_flags & CIFS_FATTR_NEED_REVAL)
97			return;
98retry:
99		dentry = d_alloc_parallel(parent, name, &wq);
100	}
101	if (IS_ERR(dentry))
102		return;
103	if (!d_in_lookup(dentry)) {
104		inode = d_inode(dentry);
105		if (inode) {
106			if (d_mountpoint(dentry)) {
107				dput(dentry);
108				return;
109			}
110			/*
111			 * If we're generating inode numbers, then we don't
112			 * want to clobber the existing one with the one that
113			 * the readdir code created.
114			 */
115			if (!(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM))
116				fattr->cf_uniqueid = CIFS_I(inode)->uniqueid;
117
118			/* update inode in place
119			 * if both i_ino and i_mode didn't change */
120			if (CIFS_I(inode)->uniqueid == fattr->cf_uniqueid &&
121			    (inode->i_mode & S_IFMT) ==
122			    (fattr->cf_mode & S_IFMT)) {
123				cifs_fattr_to_inode(inode, fattr);
124				dput(dentry);
125				return;
126			}
127		}
128		d_invalidate(dentry);
129		dput(dentry);
130		goto retry;
131	} else {
132		inode = cifs_iget(sb, fattr);
133		if (!inode)
134			inode = ERR_PTR(-ENOMEM);
135		alias = d_splice_alias(inode, dentry);
136		d_lookup_done(dentry);
137		if (alias && !IS_ERR(alias))
138			dput(alias);
139	}
140	dput(dentry);
141}
142
143static bool reparse_file_needs_reval(const struct cifs_fattr *fattr)
144{
145	if (!(fattr->cf_cifsattrs & ATTR_REPARSE))
146		return false;
147	/*
148	 * The DFS tags should be only intepreted by server side as per
149	 * MS-FSCC 2.1.2.1, but let's include them anyway.
150	 *
151	 * Besides, if cf_cifstag is unset (0), then we still need it to be
152	 * revalidated to know exactly what reparse point it is.
153	 */
154	switch (fattr->cf_cifstag) {
155	case IO_REPARSE_TAG_DFS:
156	case IO_REPARSE_TAG_DFSR:
157	case IO_REPARSE_TAG_SYMLINK:
158	case IO_REPARSE_TAG_NFS:
159	case 0:
160		return true;
161	}
162	return false;
163}
164
165static void
166cifs_fill_common_info(struct cifs_fattr *fattr, struct cifs_sb_info *cifs_sb)
167{
168	fattr->cf_uid = cifs_sb->mnt_uid;
169	fattr->cf_gid = cifs_sb->mnt_gid;
170
171	/*
172	 * The IO_REPARSE_TAG_LX_ tags originally were used by WSL but they
173	 * are preferred by the Linux client in some cases since, unlike
174	 * the NFS reparse tag (or EAs), they don't require an extra query
175	 * to determine which type of special file they represent.
176	 * TODO: go through all documented  reparse tags to see if we can
177	 * reasonably map some of them to directories vs. files vs. symlinks
178	 */
179	if (fattr->cf_cifsattrs & ATTR_DIRECTORY) {
180		fattr->cf_mode = S_IFDIR | cifs_sb->mnt_dir_mode;
181		fattr->cf_dtype = DT_DIR;
182	} else if (fattr->cf_cifstag == IO_REPARSE_TAG_LX_SYMLINK) {
183		fattr->cf_mode |= S_IFLNK | cifs_sb->mnt_file_mode;
184		fattr->cf_dtype = DT_LNK;
185	} else if (fattr->cf_cifstag == IO_REPARSE_TAG_LX_FIFO) {
186		fattr->cf_mode |= S_IFIFO | cifs_sb->mnt_file_mode;
187		fattr->cf_dtype = DT_FIFO;
188	} else if (fattr->cf_cifstag == IO_REPARSE_TAG_AF_UNIX) {
189		fattr->cf_mode |= S_IFSOCK | cifs_sb->mnt_file_mode;
190		fattr->cf_dtype = DT_SOCK;
191	} else if (fattr->cf_cifstag == IO_REPARSE_TAG_LX_CHR) {
192		fattr->cf_mode |= S_IFCHR | cifs_sb->mnt_file_mode;
193		fattr->cf_dtype = DT_CHR;
194	} else if (fattr->cf_cifstag == IO_REPARSE_TAG_LX_BLK) {
195		fattr->cf_mode |= S_IFBLK | cifs_sb->mnt_file_mode;
196		fattr->cf_dtype = DT_BLK;
197	} else { /* TODO: should we mark some other reparse points (like DFSR) as directories? */
198		fattr->cf_mode = S_IFREG | cifs_sb->mnt_file_mode;
199		fattr->cf_dtype = DT_REG;
200	}
201
202	/*
203	 * We need to revalidate it further to make a decision about whether it
204	 * is a symbolic link, DFS referral or a reparse point with a direct
205	 * access like junctions, deduplicated files, NFS symlinks.
206	 */
207	if (reparse_file_needs_reval(fattr))
208		fattr->cf_flags |= CIFS_FATTR_NEED_REVAL;
209
210	/* non-unix readdir doesn't provide nlink */
211	fattr->cf_flags |= CIFS_FATTR_UNKNOWN_NLINK;
212
213	if (fattr->cf_cifsattrs & ATTR_READONLY)
214		fattr->cf_mode &= ~S_IWUGO;
215
216	/*
217	 * We of course don't get ACL info in FIND_FIRST/NEXT results, so
218	 * mark it for revalidation so that "ls -l" will look right. It might
219	 * be super-slow, but if we don't do this then the ownership of files
220	 * may look wrong since the inodes may not have timed out by the time
221	 * "ls" does a stat() call on them.
222	 */
223	if ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_ACL) ||
224	    (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MODE_FROM_SID))
225		fattr->cf_flags |= CIFS_FATTR_NEED_REVAL;
226
227	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_UNX_EMUL &&
228	    fattr->cf_cifsattrs & ATTR_SYSTEM) {
229		if (fattr->cf_eof == 0)  {
230			fattr->cf_mode &= ~S_IFMT;
231			fattr->cf_mode |= S_IFIFO;
232			fattr->cf_dtype = DT_FIFO;
233		} else {
234			/*
235			 * trying to get the type and mode via SFU can be slow,
236			 * so just call those regular files for now, and mark
237			 * for reval
238			 */
239			fattr->cf_flags |= CIFS_FATTR_NEED_REVAL;
240		}
241	}
242}
243
244/* Fill a cifs_fattr struct with info from SMB_FIND_FILE_POSIX_INFO. */
245static void
246cifs_posix_to_fattr(struct cifs_fattr *fattr, struct smb2_posix_info *info,
247		    struct cifs_sb_info *cifs_sb)
248{
249	struct smb2_posix_info_parsed parsed;
250
251	posix_info_parse(info, NULL, &parsed);
252
253	memset(fattr, 0, sizeof(*fattr));
254	fattr->cf_uniqueid = le64_to_cpu(info->Inode);
255	fattr->cf_bytes = le64_to_cpu(info->AllocationSize);
256	fattr->cf_eof = le64_to_cpu(info->EndOfFile);
257
258	fattr->cf_atime = cifs_NTtimeToUnix(info->LastAccessTime);
259	fattr->cf_mtime = cifs_NTtimeToUnix(info->LastWriteTime);
260	fattr->cf_ctime = cifs_NTtimeToUnix(info->CreationTime);
261
262	fattr->cf_nlink = le32_to_cpu(info->HardLinks);
263	fattr->cf_cifsattrs = le32_to_cpu(info->DosAttributes);
264
265	/*
266	 * Since we set the inode type below we need to mask off
267	 * to avoid strange results if bits set above.
268	 * XXX: why not make server&client use the type bits?
269	 */
270	fattr->cf_mode = le32_to_cpu(info->Mode) & ~S_IFMT;
271
272	cifs_dbg(FYI, "posix fattr: dev %d, reparse %d, mode %o\n",
273		 le32_to_cpu(info->DeviceId),
274		 le32_to_cpu(info->ReparseTag),
275		 le32_to_cpu(info->Mode));
276
277	if (fattr->cf_cifsattrs & ATTR_DIRECTORY) {
278		fattr->cf_mode |= S_IFDIR;
279		fattr->cf_dtype = DT_DIR;
280	} else {
281		/*
282		 * mark anything that is not a dir as regular
283		 * file. special files should have the REPARSE
284		 * attribute and will be marked as needing revaluation
285		 */
286		fattr->cf_mode |= S_IFREG;
287		fattr->cf_dtype = DT_REG;
288	}
289
290	if (reparse_file_needs_reval(fattr))
291		fattr->cf_flags |= CIFS_FATTR_NEED_REVAL;
292
293	sid_to_id(cifs_sb, &parsed.owner, fattr, SIDOWNER);
294	sid_to_id(cifs_sb, &parsed.group, fattr, SIDGROUP);
295}
296
297static void __dir_info_to_fattr(struct cifs_fattr *fattr, const void *info)
298{
299	const FILE_DIRECTORY_INFO *fi = info;
300
301	memset(fattr, 0, sizeof(*fattr));
302	fattr->cf_cifsattrs = le32_to_cpu(fi->ExtFileAttributes);
303	fattr->cf_eof = le64_to_cpu(fi->EndOfFile);
304	fattr->cf_bytes = le64_to_cpu(fi->AllocationSize);
305	fattr->cf_createtime = le64_to_cpu(fi->CreationTime);
306	fattr->cf_atime = cifs_NTtimeToUnix(fi->LastAccessTime);
307	fattr->cf_ctime = cifs_NTtimeToUnix(fi->ChangeTime);
308	fattr->cf_mtime = cifs_NTtimeToUnix(fi->LastWriteTime);
309}
310
311void
312cifs_dir_info_to_fattr(struct cifs_fattr *fattr, FILE_DIRECTORY_INFO *info,
313		       struct cifs_sb_info *cifs_sb)
314{
315	__dir_info_to_fattr(fattr, info);
316	cifs_fill_common_info(fattr, cifs_sb);
317}
318
319static void cifs_fulldir_info_to_fattr(struct cifs_fattr *fattr,
320				       SEARCH_ID_FULL_DIR_INFO *info,
321				       struct cifs_sb_info *cifs_sb)
322{
323	__dir_info_to_fattr(fattr, info);
324
325	/* See MS-FSCC 2.4.18 FileIdFullDirectoryInformation */
326	if (fattr->cf_cifsattrs & ATTR_REPARSE)
327		fattr->cf_cifstag = le32_to_cpu(info->EaSize);
328	cifs_fill_common_info(fattr, cifs_sb);
329}
330
331static void
332cifs_std_info_to_fattr(struct cifs_fattr *fattr, FIND_FILE_STANDARD_INFO *info,
333		       struct cifs_sb_info *cifs_sb)
334{
335	int offset = cifs_sb_master_tcon(cifs_sb)->ses->server->timeAdj;
336
337	memset(fattr, 0, sizeof(*fattr));
338	fattr->cf_atime = cnvrtDosUnixTm(info->LastAccessDate,
339					    info->LastAccessTime, offset);
340	fattr->cf_ctime = cnvrtDosUnixTm(info->LastWriteDate,
341					    info->LastWriteTime, offset);
342	fattr->cf_mtime = cnvrtDosUnixTm(info->LastWriteDate,
343					    info->LastWriteTime, offset);
344
345	fattr->cf_cifsattrs = le16_to_cpu(info->Attributes);
346	fattr->cf_bytes = le32_to_cpu(info->AllocationSize);
347	fattr->cf_eof = le32_to_cpu(info->DataSize);
348
349	cifs_fill_common_info(fattr, cifs_sb);
350}
351
352/* BB eventually need to add the following helper function to
353      resolve NT_STATUS_STOPPED_ON_SYMLINK return code when
354      we try to do FindFirst on (NTFS) directory symlinks */
355/*
356int get_symlink_reparse_path(char *full_path, struct cifs_sb_info *cifs_sb,
357			     unsigned int xid)
358{
359	__u16 fid;
360	int len;
361	int oplock = 0;
362	int rc;
363	struct cifs_tcon *ptcon = cifs_sb_tcon(cifs_sb);
364	char *tmpbuffer;
365
366	rc = CIFSSMBOpen(xid, ptcon, full_path, FILE_OPEN, GENERIC_READ,
367			OPEN_REPARSE_POINT, &fid, &oplock, NULL,
368			cifs_sb->local_nls,
369			cifs_remap(cifs_sb);
370	if (!rc) {
371		tmpbuffer = kmalloc(maxpath);
372		rc = CIFSSMBQueryReparseLinkInfo(xid, ptcon, full_path,
373				tmpbuffer,
374				maxpath -1,
375				fid,
376				cifs_sb->local_nls);
377		if (CIFSSMBClose(xid, ptcon, fid)) {
378			cifs_dbg(FYI, "Error closing temporary reparsepoint open\n");
379		}
380	}
381}
382 */
383
384static int
385initiate_cifs_search(const unsigned int xid, struct file *file,
386		     char *full_path)
387{
388	__u16 search_flags;
389	int rc = 0;
390	struct cifsFileInfo *cifsFile;
391	struct cifs_sb_info *cifs_sb = CIFS_FILE_SB(file);
392	struct tcon_link *tlink = NULL;
393	struct cifs_tcon *tcon;
394	struct TCP_Server_Info *server;
395
396	if (file->private_data == NULL) {
397		tlink = cifs_sb_tlink(cifs_sb);
398		if (IS_ERR(tlink))
399			return PTR_ERR(tlink);
400
401		cifsFile = kzalloc(sizeof(struct cifsFileInfo), GFP_KERNEL);
402		if (cifsFile == NULL) {
403			rc = -ENOMEM;
404			goto error_exit;
405		}
406		spin_lock_init(&cifsFile->file_info_lock);
407		file->private_data = cifsFile;
408		cifsFile->tlink = cifs_get_tlink(tlink);
409		tcon = tlink_tcon(tlink);
410	} else {
411		cifsFile = file->private_data;
412		tcon = tlink_tcon(cifsFile->tlink);
413	}
414
415	server = tcon->ses->server;
416
417	if (!server->ops->query_dir_first) {
418		rc = -ENOSYS;
419		goto error_exit;
420	}
421
422	cifsFile->invalidHandle = true;
423	cifsFile->srch_inf.endOfSearch = false;
424
425	cifs_dbg(FYI, "Full path: %s start at: %lld\n", full_path, file->f_pos);
426
427ffirst_retry:
428	/* test for Unix extensions */
429	/* but now check for them on the share/mount not on the SMB session */
430	/* if (cap_unix(tcon->ses) { */
431	if (tcon->unix_ext)
432		cifsFile->srch_inf.info_level = SMB_FIND_FILE_UNIX;
433	else if (tcon->posix_extensions)
434		cifsFile->srch_inf.info_level = SMB_FIND_FILE_POSIX_INFO;
435	else if ((tcon->ses->capabilities &
436		  tcon->ses->server->vals->cap_nt_find) == 0) {
437		cifsFile->srch_inf.info_level = SMB_FIND_FILE_INFO_STANDARD;
438	} else if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM) {
439		cifsFile->srch_inf.info_level = SMB_FIND_FILE_ID_FULL_DIR_INFO;
440	} else /* not srvinos - BB fixme add check for backlevel? */ {
441		cifsFile->srch_inf.info_level = SMB_FIND_FILE_DIRECTORY_INFO;
442	}
443
444	search_flags = CIFS_SEARCH_CLOSE_AT_END | CIFS_SEARCH_RETURN_RESUME;
445	if (backup_cred(cifs_sb))
446		search_flags |= CIFS_SEARCH_BACKUP_SEARCH;
447
448	rc = server->ops->query_dir_first(xid, tcon, full_path, cifs_sb,
449					  &cifsFile->fid, search_flags,
450					  &cifsFile->srch_inf);
451
452	if (rc == 0)
453		cifsFile->invalidHandle = false;
454	/* BB add following call to handle readdir on new NTFS symlink errors
455	else if STATUS_STOPPED_ON_SYMLINK
456		call get_symlink_reparse_path and retry with new path */
457	else if ((rc == -EOPNOTSUPP) &&
458		(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM)) {
459		cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_SERVER_INUM;
460		goto ffirst_retry;
461	}
462error_exit:
463	cifs_put_tlink(tlink);
464	return rc;
465}
466
467/* return length of unicode string in bytes */
468static int cifs_unicode_bytelen(const char *str)
469{
470	int len;
471	const __le16 *ustr = (const __le16 *)str;
472
473	for (len = 0; len <= PATH_MAX; len++) {
474		if (ustr[len] == 0)
475			return len << 1;
476	}
477	cifs_dbg(FYI, "Unicode string longer than PATH_MAX found\n");
478	return len << 1;
479}
480
481static char *nxt_dir_entry(char *old_entry, char *end_of_smb, int level)
482{
483	char *new_entry;
484	FILE_DIRECTORY_INFO *pDirInfo = (FILE_DIRECTORY_INFO *)old_entry;
485
486	if (level == SMB_FIND_FILE_INFO_STANDARD) {
487		FIND_FILE_STANDARD_INFO *pfData;
488		pfData = (FIND_FILE_STANDARD_INFO *)pDirInfo;
489
490		new_entry = old_entry + sizeof(FIND_FILE_STANDARD_INFO) +
491				pfData->FileNameLength;
492	} else {
493		u32 next_offset = le32_to_cpu(pDirInfo->NextEntryOffset);
494
495		if (old_entry + next_offset < old_entry) {
496			cifs_dbg(VFS, "Invalid offset %u\n", next_offset);
497			return NULL;
498		}
499		new_entry = old_entry + next_offset;
500	}
501	cifs_dbg(FYI, "new entry %p old entry %p\n", new_entry, old_entry);
502	/* validate that new_entry is not past end of SMB */
503	if (new_entry >= end_of_smb) {
504		cifs_dbg(VFS, "search entry %p began after end of SMB %p old entry %p\n",
505			 new_entry, end_of_smb, old_entry);
506		return NULL;
507	} else if (((level == SMB_FIND_FILE_INFO_STANDARD) &&
508		    (new_entry + sizeof(FIND_FILE_STANDARD_INFO) > end_of_smb))
509		  || ((level != SMB_FIND_FILE_INFO_STANDARD) &&
510		   (new_entry + sizeof(FILE_DIRECTORY_INFO) > end_of_smb)))  {
511		cifs_dbg(VFS, "search entry %p extends after end of SMB %p\n",
512			 new_entry, end_of_smb);
513		return NULL;
514	} else
515		return new_entry;
516
517}
518
519struct cifs_dirent {
520	const char	*name;
521	size_t		namelen;
522	u32		resume_key;
523	u64		ino;
524};
525
526static void cifs_fill_dirent_posix(struct cifs_dirent *de,
527				   const struct smb2_posix_info *info)
528{
529	struct smb2_posix_info_parsed parsed;
530
531	/* payload should have already been checked at this point */
532	if (posix_info_parse(info, NULL, &parsed) < 0) {
533		cifs_dbg(VFS, "Invalid POSIX info payload\n");
534		return;
535	}
536
537	de->name = parsed.name;
538	de->namelen = parsed.name_len;
539	de->resume_key = info->Ignored;
540	de->ino = le64_to_cpu(info->Inode);
541}
542
543static void cifs_fill_dirent_unix(struct cifs_dirent *de,
544		const FILE_UNIX_INFO *info, bool is_unicode)
545{
546	de->name = &info->FileName[0];
547	if (is_unicode)
548		de->namelen = cifs_unicode_bytelen(de->name);
549	else
550		de->namelen = strnlen(de->name, PATH_MAX);
551	de->resume_key = info->ResumeKey;
552	de->ino = le64_to_cpu(info->basic.UniqueId);
553}
554
555static void cifs_fill_dirent_dir(struct cifs_dirent *de,
556		const FILE_DIRECTORY_INFO *info)
557{
558	de->name = &info->FileName[0];
559	de->namelen = le32_to_cpu(info->FileNameLength);
560	de->resume_key = info->FileIndex;
561}
562
563static void cifs_fill_dirent_full(struct cifs_dirent *de,
564		const FILE_FULL_DIRECTORY_INFO *info)
565{
566	de->name = &info->FileName[0];
567	de->namelen = le32_to_cpu(info->FileNameLength);
568	de->resume_key = info->FileIndex;
569}
570
571static void cifs_fill_dirent_search(struct cifs_dirent *de,
572		const SEARCH_ID_FULL_DIR_INFO *info)
573{
574	de->name = &info->FileName[0];
575	de->namelen = le32_to_cpu(info->FileNameLength);
576	de->resume_key = info->FileIndex;
577	de->ino = le64_to_cpu(info->UniqueId);
578}
579
580static void cifs_fill_dirent_both(struct cifs_dirent *de,
581		const FILE_BOTH_DIRECTORY_INFO *info)
582{
583	de->name = &info->FileName[0];
584	de->namelen = le32_to_cpu(info->FileNameLength);
585	de->resume_key = info->FileIndex;
586}
587
588static void cifs_fill_dirent_std(struct cifs_dirent *de,
589		const FIND_FILE_STANDARD_INFO *info)
590{
591	de->name = &info->FileName[0];
592	/* one byte length, no endianess conversion */
593	de->namelen = info->FileNameLength;
594	de->resume_key = info->ResumeKey;
595}
596
597static int cifs_fill_dirent(struct cifs_dirent *de, const void *info,
598		u16 level, bool is_unicode)
599{
600	memset(de, 0, sizeof(*de));
601
602	switch (level) {
603	case SMB_FIND_FILE_POSIX_INFO:
604		cifs_fill_dirent_posix(de, info);
605		break;
606	case SMB_FIND_FILE_UNIX:
607		cifs_fill_dirent_unix(de, info, is_unicode);
608		break;
609	case SMB_FIND_FILE_DIRECTORY_INFO:
610		cifs_fill_dirent_dir(de, info);
611		break;
612	case SMB_FIND_FILE_FULL_DIRECTORY_INFO:
613		cifs_fill_dirent_full(de, info);
614		break;
615	case SMB_FIND_FILE_ID_FULL_DIR_INFO:
616		cifs_fill_dirent_search(de, info);
617		break;
618	case SMB_FIND_FILE_BOTH_DIRECTORY_INFO:
619		cifs_fill_dirent_both(de, info);
620		break;
621	case SMB_FIND_FILE_INFO_STANDARD:
622		cifs_fill_dirent_std(de, info);
623		break;
624	default:
625		cifs_dbg(FYI, "Unknown findfirst level %d\n", level);
626		return -EINVAL;
627	}
628
629	return 0;
630}
631
632#define UNICODE_DOT cpu_to_le16(0x2e)
633
634/* return 0 if no match and 1 for . (current directory) and 2 for .. (parent) */
635static int cifs_entry_is_dot(struct cifs_dirent *de, bool is_unicode)
636{
637	int rc = 0;
638
639	if (!de->name)
640		return 0;
641
642	if (is_unicode) {
643		__le16 *ufilename = (__le16 *)de->name;
644		if (de->namelen == 2) {
645			/* check for . */
646			if (ufilename[0] == UNICODE_DOT)
647				rc = 1;
648		} else if (de->namelen == 4) {
649			/* check for .. */
650			if (ufilename[0] == UNICODE_DOT &&
651			    ufilename[1] == UNICODE_DOT)
652				rc = 2;
653		}
654	} else /* ASCII */ {
655		if (de->namelen == 1) {
656			if (de->name[0] == '.')
657				rc = 1;
658		} else if (de->namelen == 2) {
659			if (de->name[0] == '.' && de->name[1] == '.')
660				rc = 2;
661		}
662	}
663
664	return rc;
665}
666
667/* Check if directory that we are searching has changed so we can decide
668   whether we can use the cached search results from the previous search */
669static int is_dir_changed(struct file *file)
670{
671	struct inode *inode = file_inode(file);
672	struct cifsInodeInfo *cifsInfo = CIFS_I(inode);
673
674	if (cifsInfo->time == 0)
675		return 1; /* directory was changed, perhaps due to unlink */
676	else
677		return 0;
678
679}
680
681static int cifs_save_resume_key(const char *current_entry,
682	struct cifsFileInfo *file_info)
683{
684	struct cifs_dirent de;
685	int rc;
686
687	rc = cifs_fill_dirent(&de, current_entry, file_info->srch_inf.info_level,
688			      file_info->srch_inf.unicode);
689	if (!rc) {
690		file_info->srch_inf.presume_name = de.name;
691		file_info->srch_inf.resume_name_len = de.namelen;
692		file_info->srch_inf.resume_key = de.resume_key;
693	}
694	return rc;
695}
696
697/*
698 * Find the corresponding entry in the search. Note that the SMB server returns
699 * search entries for . and .. which complicates logic here if we choose to
700 * parse for them and we do not assume that they are located in the findfirst
701 * return buffer. We start counting in the buffer with entry 2 and increment for
702 * every entry (do not increment for . or .. entry).
703 */
704static int
705find_cifs_entry(const unsigned int xid, struct cifs_tcon *tcon, loff_t pos,
706		struct file *file, char *full_path,
707		char **current_entry, int *num_to_ret)
708{
709	__u16 search_flags;
710	int rc = 0;
711	int pos_in_buf = 0;
712	loff_t first_entry_in_buffer;
713	loff_t index_to_find = pos;
714	struct cifsFileInfo *cfile = file->private_data;
715	struct cifs_sb_info *cifs_sb = CIFS_FILE_SB(file);
716	struct TCP_Server_Info *server = tcon->ses->server;
717	/* check if index in the buffer */
718
719	if (!server->ops->query_dir_first || !server->ops->query_dir_next)
720		return -ENOSYS;
721
722	if ((cfile == NULL) || (current_entry == NULL) || (num_to_ret == NULL))
723		return -ENOENT;
724
725	*current_entry = NULL;
726	first_entry_in_buffer = cfile->srch_inf.index_of_last_entry -
727					cfile->srch_inf.entries_in_buffer;
728
729	/*
730	 * If first entry in buf is zero then is first buffer
731	 * in search response data which means it is likely . and ..
732	 * will be in this buffer, although some servers do not return
733	 * . and .. for the root of a drive and for those we need
734	 * to start two entries earlier.
735	 */
736
737	dump_cifs_file_struct(file, "In fce ");
738	if (((index_to_find < cfile->srch_inf.index_of_last_entry) &&
739	     is_dir_changed(file)) || (index_to_find < first_entry_in_buffer)) {
740		/* close and restart search */
741		cifs_dbg(FYI, "search backing up - close and restart search\n");
742		spin_lock(&cfile->file_info_lock);
743		if (server->ops->dir_needs_close(cfile)) {
744			cfile->invalidHandle = true;
745			spin_unlock(&cfile->file_info_lock);
746			if (server->ops->close_dir)
747				server->ops->close_dir(xid, tcon, &cfile->fid);
748		} else
749			spin_unlock(&cfile->file_info_lock);
750		if (cfile->srch_inf.ntwrk_buf_start) {
751			cifs_dbg(FYI, "freeing SMB ff cache buf on search rewind\n");
752			if (cfile->srch_inf.smallBuf)
753				cifs_small_buf_release(cfile->srch_inf.
754						ntwrk_buf_start);
755			else
756				cifs_buf_release(cfile->srch_inf.
757						ntwrk_buf_start);
758			cfile->srch_inf.ntwrk_buf_start = NULL;
759		}
760		rc = initiate_cifs_search(xid, file, full_path);
761		if (rc) {
762			cifs_dbg(FYI, "error %d reinitiating a search on rewind\n",
763				 rc);
764			return rc;
765		}
766		/* FindFirst/Next set last_entry to NULL on malformed reply */
767		if (cfile->srch_inf.last_entry)
768			cifs_save_resume_key(cfile->srch_inf.last_entry, cfile);
769	}
770
771	search_flags = CIFS_SEARCH_CLOSE_AT_END | CIFS_SEARCH_RETURN_RESUME;
772	if (backup_cred(cifs_sb))
773		search_flags |= CIFS_SEARCH_BACKUP_SEARCH;
774
775	while ((index_to_find >= cfile->srch_inf.index_of_last_entry) &&
776	       (rc == 0) && !cfile->srch_inf.endOfSearch) {
777		cifs_dbg(FYI, "calling findnext2\n");
778		rc = server->ops->query_dir_next(xid, tcon, &cfile->fid,
779						 search_flags,
780						 &cfile->srch_inf);
781		/* FindFirst/Next set last_entry to NULL on malformed reply */
782		if (cfile->srch_inf.last_entry)
783			cifs_save_resume_key(cfile->srch_inf.last_entry, cfile);
784		if (rc)
785			return -ENOENT;
786	}
787	if (index_to_find < cfile->srch_inf.index_of_last_entry) {
788		/* we found the buffer that contains the entry */
789		/* scan and find it */
790		int i;
791		char *cur_ent;
792		char *end_of_smb;
793
794		if (cfile->srch_inf.ntwrk_buf_start == NULL) {
795			cifs_dbg(VFS, "ntwrk_buf_start is NULL during readdir\n");
796			return -EIO;
797		}
798
799		end_of_smb = cfile->srch_inf.ntwrk_buf_start +
800			server->ops->calc_smb_size(
801					cfile->srch_inf.ntwrk_buf_start,
802					server);
803
804		cur_ent = cfile->srch_inf.srch_entries_start;
805		first_entry_in_buffer = cfile->srch_inf.index_of_last_entry
806					- cfile->srch_inf.entries_in_buffer;
807		pos_in_buf = index_to_find - first_entry_in_buffer;
808		cifs_dbg(FYI, "found entry - pos_in_buf %d\n", pos_in_buf);
809
810		for (i = 0; (i < (pos_in_buf)) && (cur_ent != NULL); i++) {
811			/* go entry by entry figuring out which is first */
812			cur_ent = nxt_dir_entry(cur_ent, end_of_smb,
813						cfile->srch_inf.info_level);
814		}
815		if ((cur_ent == NULL) && (i < pos_in_buf)) {
816			/* BB fixme - check if we should flag this error */
817			cifs_dbg(VFS, "reached end of buf searching for pos in buf %d index to find %lld rc %d\n",
818				 pos_in_buf, index_to_find, rc);
819		}
820		rc = 0;
821		*current_entry = cur_ent;
822	} else {
823		cifs_dbg(FYI, "index not in buffer - could not findnext into it\n");
824		return 0;
825	}
826
827	if (pos_in_buf >= cfile->srch_inf.entries_in_buffer) {
828		cifs_dbg(FYI, "can not return entries pos_in_buf beyond last\n");
829		*num_to_ret = 0;
830	} else
831		*num_to_ret = cfile->srch_inf.entries_in_buffer - pos_in_buf;
832
833	return rc;
834}
835
836static int cifs_filldir(char *find_entry, struct file *file,
837		struct dir_context *ctx,
838		char *scratch_buf, unsigned int max_len)
839{
840	struct cifsFileInfo *file_info = file->private_data;
841	struct super_block *sb = file_inode(file)->i_sb;
842	struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
843	struct cifs_dirent de = { NULL, };
844	struct cifs_fattr fattr;
845	struct qstr name;
846	int rc = 0;
847	ino_t ino;
848
849	rc = cifs_fill_dirent(&de, find_entry, file_info->srch_inf.info_level,
850			      file_info->srch_inf.unicode);
851	if (rc)
852		return rc;
853
854	if (de.namelen > max_len) {
855		cifs_dbg(VFS, "bad search response length %zd past smb end\n",
856			 de.namelen);
857		return -EINVAL;
858	}
859
860	/* skip . and .. since we added them first */
861	if (cifs_entry_is_dot(&de, file_info->srch_inf.unicode))
862		return 0;
863
864	if (file_info->srch_inf.unicode) {
865		struct nls_table *nlt = cifs_sb->local_nls;
866		int map_type;
867
868		map_type = cifs_remap(cifs_sb);
869		name.name = scratch_buf;
870		name.len =
871			cifs_from_utf16((char *)name.name, (__le16 *)de.name,
872					UNICODE_NAME_MAX,
873					min_t(size_t, de.namelen,
874					      (size_t)max_len), nlt, map_type);
875		name.len -= nls_nullsize(nlt);
876	} else {
877		name.name = de.name;
878		name.len = de.namelen;
879	}
880
881	switch (file_info->srch_inf.info_level) {
882	case SMB_FIND_FILE_POSIX_INFO:
883		cifs_posix_to_fattr(&fattr,
884				    (struct smb2_posix_info *)find_entry,
885				    cifs_sb);
886		break;
887	case SMB_FIND_FILE_UNIX:
888		cifs_unix_basic_to_fattr(&fattr,
889					 &((FILE_UNIX_INFO *)find_entry)->basic,
890					 cifs_sb);
891		break;
892	case SMB_FIND_FILE_INFO_STANDARD:
893		cifs_std_info_to_fattr(&fattr,
894				       (FIND_FILE_STANDARD_INFO *)find_entry,
895				       cifs_sb);
896		break;
897	case SMB_FIND_FILE_ID_FULL_DIR_INFO:
898		cifs_fulldir_info_to_fattr(&fattr,
899					   (SEARCH_ID_FULL_DIR_INFO *)find_entry,
900					   cifs_sb);
901		break;
902	default:
903		cifs_dir_info_to_fattr(&fattr,
904				       (FILE_DIRECTORY_INFO *)find_entry,
905				       cifs_sb);
906		break;
907	}
908
909	if (de.ino && (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM)) {
910		fattr.cf_uniqueid = de.ino;
911	} else {
912		fattr.cf_uniqueid = iunique(sb, ROOT_I);
913		cifs_autodisable_serverino(cifs_sb);
914	}
915
916	if ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS) &&
917	    couldbe_mf_symlink(&fattr))
918		/*
919		 * trying to get the type and mode can be slow,
920		 * so just call those regular files for now, and mark
921		 * for reval
922		 */
923		fattr.cf_flags |= CIFS_FATTR_NEED_REVAL;
924
925	cifs_prime_dcache(file_dentry(file), &name, &fattr);
926
927	ino = cifs_uniqueid_to_ino_t(fattr.cf_uniqueid);
928	return !dir_emit(ctx, name.name, name.len, ino, fattr.cf_dtype);
929}
930
931
932int cifs_readdir(struct file *file, struct dir_context *ctx)
933{
934	int rc = 0;
935	unsigned int xid;
936	int i;
937	struct cifs_tcon *tcon;
938	struct cifsFileInfo *cifsFile = NULL;
939	char *current_entry;
940	int num_to_fill = 0;
941	char *tmp_buf = NULL;
942	char *end_of_smb;
943	unsigned int max_len;
944	char *full_path = NULL;
945
946	xid = get_xid();
947
948	full_path = build_path_from_dentry(file_dentry(file));
949	if (full_path == NULL) {
950		rc = -ENOMEM;
951		goto rddir2_exit;
952	}
953
954	/*
955	 * Ensure FindFirst doesn't fail before doing filldir() for '.' and
956	 * '..'. Otherwise we won't be able to notify VFS in case of failure.
957	 */
958	if (file->private_data == NULL) {
959		rc = initiate_cifs_search(xid, file, full_path);
960		cifs_dbg(FYI, "initiate cifs search rc %d\n", rc);
961		if (rc)
962			goto rddir2_exit;
963	}
964
965	if (!dir_emit_dots(file, ctx))
966		goto rddir2_exit;
967
968	/* 1) If search is active,
969		is in current search buffer?
970		if it before then restart search
971		if after then keep searching till find it */
972
973	cifsFile = file->private_data;
974	if (cifsFile->srch_inf.endOfSearch) {
975		if (cifsFile->srch_inf.emptyDir) {
976			cifs_dbg(FYI, "End of search, empty dir\n");
977			rc = 0;
978			goto rddir2_exit;
979		}
980	} /* else {
981		cifsFile->invalidHandle = true;
982		tcon->ses->server->close(xid, tcon, &cifsFile->fid);
983	} */
984
985	tcon = tlink_tcon(cifsFile->tlink);
986	rc = find_cifs_entry(xid, tcon, ctx->pos, file, full_path,
987			     &current_entry, &num_to_fill);
988	if (rc) {
989		cifs_dbg(FYI, "fce error %d\n", rc);
990		goto rddir2_exit;
991	} else if (current_entry != NULL) {
992		cifs_dbg(FYI, "entry %lld found\n", ctx->pos);
993	} else {
994		cifs_dbg(FYI, "Could not find entry\n");
995		goto rddir2_exit;
996	}
997	cifs_dbg(FYI, "loop through %d times filling dir for net buf %p\n",
998		 num_to_fill, cifsFile->srch_inf.ntwrk_buf_start);
999	max_len = tcon->ses->server->ops->calc_smb_size(
1000			cifsFile->srch_inf.ntwrk_buf_start,
1001			tcon->ses->server);
1002	end_of_smb = cifsFile->srch_inf.ntwrk_buf_start + max_len;
1003
1004	tmp_buf = kmalloc(UNICODE_NAME_MAX, GFP_KERNEL);
1005	if (tmp_buf == NULL) {
1006		rc = -ENOMEM;
1007		goto rddir2_exit;
1008	}
1009
1010	for (i = 0; i < num_to_fill; i++) {
1011		if (current_entry == NULL) {
1012			/* evaluate whether this case is an error */
1013			cifs_dbg(VFS, "past SMB end,  num to fill %d i %d\n",
1014				 num_to_fill, i);
1015			break;
1016		}
1017		/*
1018		 * if buggy server returns . and .. late do we want to
1019		 * check for that here?
1020		 */
1021		*tmp_buf = 0;
1022		rc = cifs_filldir(current_entry, file, ctx,
1023				  tmp_buf, max_len);
1024		if (rc) {
1025			if (rc > 0)
1026				rc = 0;
1027			break;
1028		}
1029
1030		ctx->pos++;
1031		if (ctx->pos ==
1032			cifsFile->srch_inf.index_of_last_entry) {
1033			cifs_dbg(FYI, "last entry in buf at pos %lld %s\n",
1034				 ctx->pos, tmp_buf);
1035			cifs_save_resume_key(current_entry, cifsFile);
1036			break;
1037		} else
1038			current_entry =
1039				nxt_dir_entry(current_entry, end_of_smb,
1040					cifsFile->srch_inf.info_level);
1041	}
1042	kfree(tmp_buf);
1043
1044rddir2_exit:
1045	kfree(full_path);
1046	free_xid(xid);
1047	return rc;
1048}
1049