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TOMOYO Linux Cross Reference
Linux/fs/cifs/readdir.c

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  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 
 36 /*
 37  * To be safe - for UCS to UTF-8 with strings loaded with the rare long
 38  * characters alloc more to account for such multibyte target UTF-8
 39  * characters.
 40  */
 41 #define UNICODE_NAME_MAX ((4 * NAME_MAX) + 2)
 42 
 43 #ifdef CONFIG_CIFS_DEBUG2
 44 static void dump_cifs_file_struct(struct file *file, char *label)
 45 {
 46         struct cifsFileInfo *cf;
 47 
 48         if (file) {
 49                 cf = file->private_data;
 50                 if (cf == NULL) {
 51                         cifs_dbg(FYI, "empty cifs private file data\n");
 52                         return;
 53                 }
 54                 if (cf->invalidHandle)
 55                         cifs_dbg(FYI, "invalid handle\n");
 56                 if (cf->srch_inf.endOfSearch)
 57                         cifs_dbg(FYI, "end of search\n");
 58                 if (cf->srch_inf.emptyDir)
 59                         cifs_dbg(FYI, "empty dir\n");
 60         }
 61 }
 62 #else
 63 static inline void dump_cifs_file_struct(struct file *file, char *label)
 64 {
 65 }
 66 #endif /* DEBUG2 */
 67 
 68 /*
 69  * Attempt to preload the dcache with the results from the FIND_FIRST/NEXT
 70  *
 71  * Find the dentry that matches "name". If there isn't one, create one. If it's
 72  * a negative dentry or the uniqueid changed, then drop it and recreate it.
 73  */
 74 static void
 75 cifs_prime_dcache(struct dentry *parent, struct qstr *name,
 76                     struct cifs_fattr *fattr)
 77 {
 78         struct dentry *dentry, *alias;
 79         struct inode *inode;
 80         struct super_block *sb = parent->d_inode->i_sb;
 81         struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
 82 
 83         cifs_dbg(FYI, "%s: for %s\n", __func__, name->name);
 84 
 85         dentry = d_hash_and_lookup(parent, name);
 86         if (unlikely(IS_ERR(dentry)))
 87                 return;
 88 
 89         if (dentry) {
 90                 int err;
 91 
 92                 inode = dentry->d_inode;
 93                 if (inode) {
 94                         /*
 95                          * If we're generating inode numbers, then we don't
 96                          * want to clobber the existing one with the one that
 97                          * the readdir code created.
 98                          */
 99                         if (!(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM))
100                                 fattr->cf_uniqueid = CIFS_I(inode)->uniqueid;
101 
102                         /* update inode in place if i_ino didn't change */
103                         if (CIFS_I(inode)->uniqueid == fattr->cf_uniqueid) {
104                                 cifs_fattr_to_inode(inode, fattr);
105                                 goto out;
106                         }
107                 }
108                 err = d_invalidate(dentry);
109                 dput(dentry);
110                 if (err)
111                         return;
112         }
113 
114         /*
115          * If we know that the inode will need to be revalidated immediately,
116          * then don't create a new dentry for it. We'll end up doing an on
117          * the wire call either way and this spares us an invalidation.
118          */
119         if (fattr->cf_flags & CIFS_FATTR_NEED_REVAL)
120                 return;
121 
122         dentry = d_alloc(parent, name);
123         if (!dentry)
124                 return;
125 
126         inode = cifs_iget(sb, fattr);
127         if (!inode)
128                 goto out;
129 
130         alias = d_materialise_unique(dentry, inode);
131         if (alias && !IS_ERR(alias))
132                 dput(alias);
133 out:
134         dput(dentry);
135 }
136 
137 static void
138 cifs_fill_common_info(struct cifs_fattr *fattr, struct cifs_sb_info *cifs_sb)
139 {
140         fattr->cf_uid = cifs_sb->mnt_uid;
141         fattr->cf_gid = cifs_sb->mnt_gid;
142 
143         if (fattr->cf_cifsattrs & ATTR_DIRECTORY) {
144                 fattr->cf_mode = S_IFDIR | cifs_sb->mnt_dir_mode;
145                 fattr->cf_dtype = DT_DIR;
146         } else {
147                 fattr->cf_mode = S_IFREG | cifs_sb->mnt_file_mode;
148                 fattr->cf_dtype = DT_REG;
149         }
150 
151         /*
152          * We need to revalidate it further to make a decision about whether it
153          * is a symbolic link, DFS referral or a reparse point with a direct
154          * access like junctions, deduplicated files, NFS symlinks.
155          */
156         if (fattr->cf_cifsattrs & ATTR_REPARSE)
157                 fattr->cf_flags |= CIFS_FATTR_NEED_REVAL;
158 
159         /* non-unix readdir doesn't provide nlink */
160         fattr->cf_flags |= CIFS_FATTR_UNKNOWN_NLINK;
161 
162         if (fattr->cf_cifsattrs & ATTR_READONLY)
163                 fattr->cf_mode &= ~S_IWUGO;
164 
165         /*
166          * We of course don't get ACL info in FIND_FIRST/NEXT results, so
167          * mark it for revalidation so that "ls -l" will look right. It might
168          * be super-slow, but if we don't do this then the ownership of files
169          * may look wrong since the inodes may not have timed out by the time
170          * "ls" does a stat() call on them.
171          */
172         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_ACL)
173                 fattr->cf_flags |= CIFS_FATTR_NEED_REVAL;
174 
175         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_UNX_EMUL &&
176             fattr->cf_cifsattrs & ATTR_SYSTEM) {
177                 if (fattr->cf_eof == 0)  {
178                         fattr->cf_mode &= ~S_IFMT;
179                         fattr->cf_mode |= S_IFIFO;
180                         fattr->cf_dtype = DT_FIFO;
181                 } else {
182                         /*
183                          * trying to get the type and mode via SFU can be slow,
184                          * so just call those regular files for now, and mark
185                          * for reval
186                          */
187                         fattr->cf_flags |= CIFS_FATTR_NEED_REVAL;
188                 }
189         }
190 }
191 
192 void
193 cifs_dir_info_to_fattr(struct cifs_fattr *fattr, FILE_DIRECTORY_INFO *info,
194                        struct cifs_sb_info *cifs_sb)
195 {
196         memset(fattr, 0, sizeof(*fattr));
197         fattr->cf_cifsattrs = le32_to_cpu(info->ExtFileAttributes);
198         fattr->cf_eof = le64_to_cpu(info->EndOfFile);
199         fattr->cf_bytes = le64_to_cpu(info->AllocationSize);
200         fattr->cf_createtime = le64_to_cpu(info->CreationTime);
201         fattr->cf_atime = cifs_NTtimeToUnix(info->LastAccessTime);
202         fattr->cf_ctime = cifs_NTtimeToUnix(info->ChangeTime);
203         fattr->cf_mtime = cifs_NTtimeToUnix(info->LastWriteTime);
204 
205         cifs_fill_common_info(fattr, cifs_sb);
206 }
207 
208 static void
209 cifs_std_info_to_fattr(struct cifs_fattr *fattr, FIND_FILE_STANDARD_INFO *info,
210                        struct cifs_sb_info *cifs_sb)
211 {
212         int offset = cifs_sb_master_tcon(cifs_sb)->ses->server->timeAdj;
213 
214         memset(fattr, 0, sizeof(*fattr));
215         fattr->cf_atime = cnvrtDosUnixTm(info->LastAccessDate,
216                                             info->LastAccessTime, offset);
217         fattr->cf_ctime = cnvrtDosUnixTm(info->LastWriteDate,
218                                             info->LastWriteTime, offset);
219         fattr->cf_mtime = cnvrtDosUnixTm(info->LastWriteDate,
220                                             info->LastWriteTime, offset);
221 
222         fattr->cf_cifsattrs = le16_to_cpu(info->Attributes);
223         fattr->cf_bytes = le32_to_cpu(info->AllocationSize);
224         fattr->cf_eof = le32_to_cpu(info->DataSize);
225 
226         cifs_fill_common_info(fattr, cifs_sb);
227 }
228 
229 /* BB eventually need to add the following helper function to
230       resolve NT_STATUS_STOPPED_ON_SYMLINK return code when
231       we try to do FindFirst on (NTFS) directory symlinks */
232 /*
233 int get_symlink_reparse_path(char *full_path, struct cifs_sb_info *cifs_sb,
234                              unsigned int xid)
235 {
236         __u16 fid;
237         int len;
238         int oplock = 0;
239         int rc;
240         struct cifs_tcon *ptcon = cifs_sb_tcon(cifs_sb);
241         char *tmpbuffer;
242 
243         rc = CIFSSMBOpen(xid, ptcon, full_path, FILE_OPEN, GENERIC_READ,
244                         OPEN_REPARSE_POINT, &fid, &oplock, NULL,
245                         cifs_sb->local_nls,
246                         cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR);
247         if (!rc) {
248                 tmpbuffer = kmalloc(maxpath);
249                 rc = CIFSSMBQueryReparseLinkInfo(xid, ptcon, full_path,
250                                 tmpbuffer,
251                                 maxpath -1,
252                                 fid,
253                                 cifs_sb->local_nls);
254                 if (CIFSSMBClose(xid, ptcon, fid)) {
255                         cifs_dbg(FYI, "Error closing temporary reparsepoint open\n");
256                 }
257         }
258 }
259  */
260 
261 static int
262 initiate_cifs_search(const unsigned int xid, struct file *file)
263 {
264         __u16 search_flags;
265         int rc = 0;
266         char *full_path = NULL;
267         struct cifsFileInfo *cifsFile;
268         struct cifs_sb_info *cifs_sb = CIFS_SB(file->f_path.dentry->d_sb);
269         struct tcon_link *tlink = NULL;
270         struct cifs_tcon *tcon;
271         struct TCP_Server_Info *server;
272 
273         if (file->private_data == NULL) {
274                 tlink = cifs_sb_tlink(cifs_sb);
275                 if (IS_ERR(tlink))
276                         return PTR_ERR(tlink);
277 
278                 cifsFile = kzalloc(sizeof(struct cifsFileInfo), GFP_KERNEL);
279                 if (cifsFile == NULL) {
280                         rc = -ENOMEM;
281                         goto error_exit;
282                 }
283                 spin_lock_init(&cifsFile->file_info_lock);
284                 file->private_data = cifsFile;
285                 cifsFile->tlink = cifs_get_tlink(tlink);
286                 tcon = tlink_tcon(tlink);
287         } else {
288                 cifsFile = file->private_data;
289                 tcon = tlink_tcon(cifsFile->tlink);
290         }
291 
292         server = tcon->ses->server;
293 
294         if (!server->ops->query_dir_first) {
295                 rc = -ENOSYS;
296                 goto error_exit;
297         }
298 
299         cifsFile->invalidHandle = true;
300         cifsFile->srch_inf.endOfSearch = false;
301 
302         full_path = build_path_from_dentry(file->f_path.dentry);
303         if (full_path == NULL) {
304                 rc = -ENOMEM;
305                 goto error_exit;
306         }
307 
308         cifs_dbg(FYI, "Full path: %s start at: %lld\n", full_path, file->f_pos);
309 
310 ffirst_retry:
311         /* test for Unix extensions */
312         /* but now check for them on the share/mount not on the SMB session */
313         /* if (cap_unix(tcon->ses) { */
314         if (tcon->unix_ext)
315                 cifsFile->srch_inf.info_level = SMB_FIND_FILE_UNIX;
316         else if ((tcon->ses->capabilities &
317                   tcon->ses->server->vals->cap_nt_find) == 0) {
318                 cifsFile->srch_inf.info_level = SMB_FIND_FILE_INFO_STANDARD;
319         } else if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM) {
320                 cifsFile->srch_inf.info_level = SMB_FIND_FILE_ID_FULL_DIR_INFO;
321         } else /* not srvinos - BB fixme add check for backlevel? */ {
322                 cifsFile->srch_inf.info_level = SMB_FIND_FILE_DIRECTORY_INFO;
323         }
324 
325         search_flags = CIFS_SEARCH_CLOSE_AT_END | CIFS_SEARCH_RETURN_RESUME;
326         if (backup_cred(cifs_sb))
327                 search_flags |= CIFS_SEARCH_BACKUP_SEARCH;
328 
329         rc = server->ops->query_dir_first(xid, tcon, full_path, cifs_sb,
330                                           &cifsFile->fid, search_flags,
331                                           &cifsFile->srch_inf);
332 
333         if (rc == 0)
334                 cifsFile->invalidHandle = false;
335         /* BB add following call to handle readdir on new NTFS symlink errors
336         else if STATUS_STOPPED_ON_SYMLINK
337                 call get_symlink_reparse_path and retry with new path */
338         else if ((rc == -EOPNOTSUPP) &&
339                 (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM)) {
340                 cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_SERVER_INUM;
341                 goto ffirst_retry;
342         }
343 error_exit:
344         kfree(full_path);
345         cifs_put_tlink(tlink);
346         return rc;
347 }
348 
349 /* return length of unicode string in bytes */
350 static int cifs_unicode_bytelen(const char *str)
351 {
352         int len;
353         const __le16 *ustr = (const __le16 *)str;
354 
355         for (len = 0; len <= PATH_MAX; len++) {
356                 if (ustr[len] == 0)
357                         return len << 1;
358         }
359         cifs_dbg(FYI, "Unicode string longer than PATH_MAX found\n");
360         return len << 1;
361 }
362 
363 static char *nxt_dir_entry(char *old_entry, char *end_of_smb, int level)
364 {
365         char *new_entry;
366         FILE_DIRECTORY_INFO *pDirInfo = (FILE_DIRECTORY_INFO *)old_entry;
367 
368         if (level == SMB_FIND_FILE_INFO_STANDARD) {
369                 FIND_FILE_STANDARD_INFO *pfData;
370                 pfData = (FIND_FILE_STANDARD_INFO *)pDirInfo;
371 
372                 new_entry = old_entry + sizeof(FIND_FILE_STANDARD_INFO) +
373                                 pfData->FileNameLength;
374         } else
375                 new_entry = old_entry + le32_to_cpu(pDirInfo->NextEntryOffset);
376         cifs_dbg(FYI, "new entry %p old entry %p\n", new_entry, old_entry);
377         /* validate that new_entry is not past end of SMB */
378         if (new_entry >= end_of_smb) {
379                 cifs_dbg(VFS, "search entry %p began after end of SMB %p old entry %p\n",
380                          new_entry, end_of_smb, old_entry);
381                 return NULL;
382         } else if (((level == SMB_FIND_FILE_INFO_STANDARD) &&
383                     (new_entry + sizeof(FIND_FILE_STANDARD_INFO) > end_of_smb))
384                   || ((level != SMB_FIND_FILE_INFO_STANDARD) &&
385                    (new_entry + sizeof(FILE_DIRECTORY_INFO) > end_of_smb)))  {
386                 cifs_dbg(VFS, "search entry %p extends after end of SMB %p\n",
387                          new_entry, end_of_smb);
388                 return NULL;
389         } else
390                 return new_entry;
391 
392 }
393 
394 struct cifs_dirent {
395         const char      *name;
396         size_t          namelen;
397         u32             resume_key;
398         u64             ino;
399 };
400 
401 static void cifs_fill_dirent_unix(struct cifs_dirent *de,
402                 const FILE_UNIX_INFO *info, bool is_unicode)
403 {
404         de->name = &info->FileName[0];
405         if (is_unicode)
406                 de->namelen = cifs_unicode_bytelen(de->name);
407         else
408                 de->namelen = strnlen(de->name, PATH_MAX);
409         de->resume_key = info->ResumeKey;
410         de->ino = le64_to_cpu(info->basic.UniqueId);
411 }
412 
413 static void cifs_fill_dirent_dir(struct cifs_dirent *de,
414                 const FILE_DIRECTORY_INFO *info)
415 {
416         de->name = &info->FileName[0];
417         de->namelen = le32_to_cpu(info->FileNameLength);
418         de->resume_key = info->FileIndex;
419 }
420 
421 static void cifs_fill_dirent_full(struct cifs_dirent *de,
422                 const FILE_FULL_DIRECTORY_INFO *info)
423 {
424         de->name = &info->FileName[0];
425         de->namelen = le32_to_cpu(info->FileNameLength);
426         de->resume_key = info->FileIndex;
427 }
428 
429 static void cifs_fill_dirent_search(struct cifs_dirent *de,
430                 const SEARCH_ID_FULL_DIR_INFO *info)
431 {
432         de->name = &info->FileName[0];
433         de->namelen = le32_to_cpu(info->FileNameLength);
434         de->resume_key = info->FileIndex;
435         de->ino = le64_to_cpu(info->UniqueId);
436 }
437 
438 static void cifs_fill_dirent_both(struct cifs_dirent *de,
439                 const FILE_BOTH_DIRECTORY_INFO *info)
440 {
441         de->name = &info->FileName[0];
442         de->namelen = le32_to_cpu(info->FileNameLength);
443         de->resume_key = info->FileIndex;
444 }
445 
446 static void cifs_fill_dirent_std(struct cifs_dirent *de,
447                 const FIND_FILE_STANDARD_INFO *info)
448 {
449         de->name = &info->FileName[0];
450         /* one byte length, no endianess conversion */
451         de->namelen = info->FileNameLength;
452         de->resume_key = info->ResumeKey;
453 }
454 
455 static int cifs_fill_dirent(struct cifs_dirent *de, const void *info,
456                 u16 level, bool is_unicode)
457 {
458         memset(de, 0, sizeof(*de));
459 
460         switch (level) {
461         case SMB_FIND_FILE_UNIX:
462                 cifs_fill_dirent_unix(de, info, is_unicode);
463                 break;
464         case SMB_FIND_FILE_DIRECTORY_INFO:
465                 cifs_fill_dirent_dir(de, info);
466                 break;
467         case SMB_FIND_FILE_FULL_DIRECTORY_INFO:
468                 cifs_fill_dirent_full(de, info);
469                 break;
470         case SMB_FIND_FILE_ID_FULL_DIR_INFO:
471                 cifs_fill_dirent_search(de, info);
472                 break;
473         case SMB_FIND_FILE_BOTH_DIRECTORY_INFO:
474                 cifs_fill_dirent_both(de, info);
475                 break;
476         case SMB_FIND_FILE_INFO_STANDARD:
477                 cifs_fill_dirent_std(de, info);
478                 break;
479         default:
480                 cifs_dbg(FYI, "Unknown findfirst level %d\n", level);
481                 return -EINVAL;
482         }
483 
484         return 0;
485 }
486 
487 #define UNICODE_DOT cpu_to_le16(0x2e)
488 
489 /* return 0 if no match and 1 for . (current directory) and 2 for .. (parent) */
490 static int cifs_entry_is_dot(struct cifs_dirent *de, bool is_unicode)
491 {
492         int rc = 0;
493 
494         if (!de->name)
495                 return 0;
496 
497         if (is_unicode) {
498                 __le16 *ufilename = (__le16 *)de->name;
499                 if (de->namelen == 2) {
500                         /* check for . */
501                         if (ufilename[0] == UNICODE_DOT)
502                                 rc = 1;
503                 } else if (de->namelen == 4) {
504                         /* check for .. */
505                         if (ufilename[0] == UNICODE_DOT &&
506                             ufilename[1] == UNICODE_DOT)
507                                 rc = 2;
508                 }
509         } else /* ASCII */ {
510                 if (de->namelen == 1) {
511                         if (de->name[0] == '.')
512                                 rc = 1;
513                 } else if (de->namelen == 2) {
514                         if (de->name[0] == '.' && de->name[1] == '.')
515                                 rc = 2;
516                 }
517         }
518 
519         return rc;
520 }
521 
522 /* Check if directory that we are searching has changed so we can decide
523    whether we can use the cached search results from the previous search */
524 static int is_dir_changed(struct file *file)
525 {
526         struct inode *inode = file_inode(file);
527         struct cifsInodeInfo *cifsInfo = CIFS_I(inode);
528 
529         if (cifsInfo->time == 0)
530                 return 1; /* directory was changed, perhaps due to unlink */
531         else
532                 return 0;
533 
534 }
535 
536 static int cifs_save_resume_key(const char *current_entry,
537         struct cifsFileInfo *file_info)
538 {
539         struct cifs_dirent de;
540         int rc;
541 
542         rc = cifs_fill_dirent(&de, current_entry, file_info->srch_inf.info_level,
543                               file_info->srch_inf.unicode);
544         if (!rc) {
545                 file_info->srch_inf.presume_name = de.name;
546                 file_info->srch_inf.resume_name_len = de.namelen;
547                 file_info->srch_inf.resume_key = de.resume_key;
548         }
549         return rc;
550 }
551 
552 /*
553  * Find the corresponding entry in the search. Note that the SMB server returns
554  * search entries for . and .. which complicates logic here if we choose to
555  * parse for them and we do not assume that they are located in the findfirst
556  * return buffer. We start counting in the buffer with entry 2 and increment for
557  * every entry (do not increment for . or .. entry).
558  */
559 static int
560 find_cifs_entry(const unsigned int xid, struct cifs_tcon *tcon, loff_t pos,
561                 struct file *file, char **current_entry, int *num_to_ret)
562 {
563         __u16 search_flags;
564         int rc = 0;
565         int pos_in_buf = 0;
566         loff_t first_entry_in_buffer;
567         loff_t index_to_find = pos;
568         struct cifsFileInfo *cfile = file->private_data;
569         struct cifs_sb_info *cifs_sb = CIFS_SB(file->f_path.dentry->d_sb);
570         struct TCP_Server_Info *server = tcon->ses->server;
571         /* check if index in the buffer */
572 
573         if (!server->ops->query_dir_first || !server->ops->query_dir_next)
574                 return -ENOSYS;
575 
576         if ((cfile == NULL) || (current_entry == NULL) || (num_to_ret == NULL))
577                 return -ENOENT;
578 
579         *current_entry = NULL;
580         first_entry_in_buffer = cfile->srch_inf.index_of_last_entry -
581                                         cfile->srch_inf.entries_in_buffer;
582 
583         /*
584          * If first entry in buf is zero then is first buffer
585          * in search response data which means it is likely . and ..
586          * will be in this buffer, although some servers do not return
587          * . and .. for the root of a drive and for those we need
588          * to start two entries earlier.
589          */
590 
591         dump_cifs_file_struct(file, "In fce ");
592         if (((index_to_find < cfile->srch_inf.index_of_last_entry) &&
593              is_dir_changed(file)) || (index_to_find < first_entry_in_buffer)) {
594                 /* close and restart search */
595                 cifs_dbg(FYI, "search backing up - close and restart search\n");
596                 spin_lock(&cfile->file_info_lock);
597                 if (server->ops->dir_needs_close(cfile)) {
598                         cfile->invalidHandle = true;
599                         spin_unlock(&cfile->file_info_lock);
600                         if (server->ops->close_dir)
601                                 server->ops->close_dir(xid, tcon, &cfile->fid);
602                 } else
603                         spin_unlock(&cfile->file_info_lock);
604                 if (cfile->srch_inf.ntwrk_buf_start) {
605                         cifs_dbg(FYI, "freeing SMB ff cache buf on search rewind\n");
606                         if (cfile->srch_inf.smallBuf)
607                                 cifs_small_buf_release(cfile->srch_inf.
608                                                 ntwrk_buf_start);
609                         else
610                                 cifs_buf_release(cfile->srch_inf.
611                                                 ntwrk_buf_start);
612                         cfile->srch_inf.ntwrk_buf_start = NULL;
613                 }
614                 rc = initiate_cifs_search(xid, file);
615                 if (rc) {
616                         cifs_dbg(FYI, "error %d reinitiating a search on rewind\n",
617                                  rc);
618                         return rc;
619                 }
620                 /* FindFirst/Next set last_entry to NULL on malformed reply */
621                 if (cfile->srch_inf.last_entry)
622                         cifs_save_resume_key(cfile->srch_inf.last_entry, cfile);
623         }
624 
625         search_flags = CIFS_SEARCH_CLOSE_AT_END | CIFS_SEARCH_RETURN_RESUME;
626         if (backup_cred(cifs_sb))
627                 search_flags |= CIFS_SEARCH_BACKUP_SEARCH;
628 
629         while ((index_to_find >= cfile->srch_inf.index_of_last_entry) &&
630                (rc == 0) && !cfile->srch_inf.endOfSearch) {
631                 cifs_dbg(FYI, "calling findnext2\n");
632                 rc = server->ops->query_dir_next(xid, tcon, &cfile->fid,
633                                                  search_flags,
634                                                  &cfile->srch_inf);
635                 /* FindFirst/Next set last_entry to NULL on malformed reply */
636                 if (cfile->srch_inf.last_entry)
637                         cifs_save_resume_key(cfile->srch_inf.last_entry, cfile);
638                 if (rc)
639                         return -ENOENT;
640         }
641         if (index_to_find < cfile->srch_inf.index_of_last_entry) {
642                 /* we found the buffer that contains the entry */
643                 /* scan and find it */
644                 int i;
645                 char *cur_ent;
646                 char *end_of_smb = cfile->srch_inf.ntwrk_buf_start +
647                         server->ops->calc_smb_size(
648                                         cfile->srch_inf.ntwrk_buf_start);
649 
650                 cur_ent = cfile->srch_inf.srch_entries_start;
651                 first_entry_in_buffer = cfile->srch_inf.index_of_last_entry
652                                         - cfile->srch_inf.entries_in_buffer;
653                 pos_in_buf = index_to_find - first_entry_in_buffer;
654                 cifs_dbg(FYI, "found entry - pos_in_buf %d\n", pos_in_buf);
655 
656                 for (i = 0; (i < (pos_in_buf)) && (cur_ent != NULL); i++) {
657                         /* go entry by entry figuring out which is first */
658                         cur_ent = nxt_dir_entry(cur_ent, end_of_smb,
659                                                 cfile->srch_inf.info_level);
660                 }
661                 if ((cur_ent == NULL) && (i < pos_in_buf)) {
662                         /* BB fixme - check if we should flag this error */
663                         cifs_dbg(VFS, "reached end of buf searching for pos in buf %d index to find %lld rc %d\n",
664                                  pos_in_buf, index_to_find, rc);
665                 }
666                 rc = 0;
667                 *current_entry = cur_ent;
668         } else {
669                 cifs_dbg(FYI, "index not in buffer - could not findnext into it\n");
670                 return 0;
671         }
672 
673         if (pos_in_buf >= cfile->srch_inf.entries_in_buffer) {
674                 cifs_dbg(FYI, "can not return entries pos_in_buf beyond last\n");
675                 *num_to_ret = 0;
676         } else
677                 *num_to_ret = cfile->srch_inf.entries_in_buffer - pos_in_buf;
678 
679         return rc;
680 }
681 
682 static int cifs_filldir(char *find_entry, struct file *file,
683                 struct dir_context *ctx,
684                 char *scratch_buf, unsigned int max_len)
685 {
686         struct cifsFileInfo *file_info = file->private_data;
687         struct super_block *sb = file->f_path.dentry->d_sb;
688         struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
689         struct cifs_dirent de = { NULL, };
690         struct cifs_fattr fattr;
691         struct qstr name;
692         int rc = 0;
693         ino_t ino;
694 
695         rc = cifs_fill_dirent(&de, find_entry, file_info->srch_inf.info_level,
696                               file_info->srch_inf.unicode);
697         if (rc)
698                 return rc;
699 
700         if (de.namelen > max_len) {
701                 cifs_dbg(VFS, "bad search response length %zd past smb end\n",
702                          de.namelen);
703                 return -EINVAL;
704         }
705 
706         /* skip . and .. since we added them first */
707         if (cifs_entry_is_dot(&de, file_info->srch_inf.unicode))
708                 return 0;
709 
710         if (file_info->srch_inf.unicode) {
711                 struct nls_table *nlt = cifs_sb->local_nls;
712 
713                 name.name = scratch_buf;
714                 name.len =
715                         cifs_from_utf16((char *)name.name, (__le16 *)de.name,
716                                         UNICODE_NAME_MAX,
717                                         min_t(size_t, de.namelen,
718                                               (size_t)max_len), nlt,
719                                         cifs_sb->mnt_cifs_flags &
720                                                 CIFS_MOUNT_MAP_SPECIAL_CHR);
721                 name.len -= nls_nullsize(nlt);
722         } else {
723                 name.name = de.name;
724                 name.len = de.namelen;
725         }
726 
727         switch (file_info->srch_inf.info_level) {
728         case SMB_FIND_FILE_UNIX:
729                 cifs_unix_basic_to_fattr(&fattr,
730                                          &((FILE_UNIX_INFO *)find_entry)->basic,
731                                          cifs_sb);
732                 break;
733         case SMB_FIND_FILE_INFO_STANDARD:
734                 cifs_std_info_to_fattr(&fattr,
735                                        (FIND_FILE_STANDARD_INFO *)find_entry,
736                                        cifs_sb);
737                 break;
738         default:
739                 cifs_dir_info_to_fattr(&fattr,
740                                        (FILE_DIRECTORY_INFO *)find_entry,
741                                        cifs_sb);
742                 break;
743         }
744 
745         if (de.ino && (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM)) {
746                 fattr.cf_uniqueid = de.ino;
747         } else {
748                 fattr.cf_uniqueid = iunique(sb, ROOT_I);
749                 cifs_autodisable_serverino(cifs_sb);
750         }
751 
752         if ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS) &&
753             CIFSCouldBeMFSymlink(&fattr))
754                 /*
755                  * trying to get the type and mode can be slow,
756                  * so just call those regular files for now, and mark
757                  * for reval
758                  */
759                 fattr.cf_flags |= CIFS_FATTR_NEED_REVAL;
760 
761         cifs_prime_dcache(file->f_dentry, &name, &fattr);
762 
763         ino = cifs_uniqueid_to_ino_t(fattr.cf_uniqueid);
764         return !dir_emit(ctx, name.name, name.len, ino, fattr.cf_dtype);
765 }
766 
767 
768 int cifs_readdir(struct file *file, struct dir_context *ctx)
769 {
770         int rc = 0;
771         unsigned int xid;
772         int i;
773         struct cifs_tcon *tcon;
774         struct cifsFileInfo *cifsFile = NULL;
775         char *current_entry;
776         int num_to_fill = 0;
777         char *tmp_buf = NULL;
778         char *end_of_smb;
779         unsigned int max_len;
780 
781         xid = get_xid();
782 
783         /*
784          * Ensure FindFirst doesn't fail before doing filldir() for '.' and
785          * '..'. Otherwise we won't be able to notify VFS in case of failure.
786          */
787         if (file->private_data == NULL) {
788                 rc = initiate_cifs_search(xid, file);
789                 cifs_dbg(FYI, "initiate cifs search rc %d\n", rc);
790                 if (rc)
791                         goto rddir2_exit;
792         }
793 
794         if (!dir_emit_dots(file, ctx))
795                 goto rddir2_exit;
796 
797         /* 1) If search is active,
798                 is in current search buffer?
799                 if it before then restart search
800                 if after then keep searching till find it */
801 
802         if (file->private_data == NULL) {
803                 rc = -EINVAL;
804                 goto rddir2_exit;
805         }
806         cifsFile = file->private_data;
807         if (cifsFile->srch_inf.endOfSearch) {
808                 if (cifsFile->srch_inf.emptyDir) {
809                         cifs_dbg(FYI, "End of search, empty dir\n");
810                         rc = 0;
811                         goto rddir2_exit;
812                 }
813         } /* else {
814                 cifsFile->invalidHandle = true;
815                 tcon->ses->server->close(xid, tcon, &cifsFile->fid);
816         } */
817 
818         tcon = tlink_tcon(cifsFile->tlink);
819         rc = find_cifs_entry(xid, tcon, ctx->pos, file, &current_entry,
820                              &num_to_fill);
821         if (rc) {
822                 cifs_dbg(FYI, "fce error %d\n", rc);
823                 goto rddir2_exit;
824         } else if (current_entry != NULL) {
825                 cifs_dbg(FYI, "entry %lld found\n", ctx->pos);
826         } else {
827                 cifs_dbg(FYI, "could not find entry\n");
828                 goto rddir2_exit;
829         }
830         cifs_dbg(FYI, "loop through %d times filling dir for net buf %p\n",
831                  num_to_fill, cifsFile->srch_inf.ntwrk_buf_start);
832         max_len = tcon->ses->server->ops->calc_smb_size(
833                         cifsFile->srch_inf.ntwrk_buf_start);
834         end_of_smb = cifsFile->srch_inf.ntwrk_buf_start + max_len;
835 
836         tmp_buf = kmalloc(UNICODE_NAME_MAX, GFP_KERNEL);
837         if (tmp_buf == NULL) {
838                 rc = -ENOMEM;
839                 goto rddir2_exit;
840         }
841 
842         for (i = 0; i < num_to_fill; i++) {
843                 if (current_entry == NULL) {
844                         /* evaluate whether this case is an error */
845                         cifs_dbg(VFS, "past SMB end,  num to fill %d i %d\n",
846                                  num_to_fill, i);
847                         break;
848                 }
849                 /*
850                  * if buggy server returns . and .. late do we want to
851                  * check for that here?
852                  */
853                 *tmp_buf = 0;
854                 rc = cifs_filldir(current_entry, file, ctx,
855                                   tmp_buf, max_len);
856                 if (rc) {
857                         if (rc > 0)
858                                 rc = 0;
859                         break;
860                 }
861 
862                 ctx->pos++;
863                 if (ctx->pos ==
864                         cifsFile->srch_inf.index_of_last_entry) {
865                         cifs_dbg(FYI, "last entry in buf at pos %lld %s\n",
866                                  ctx->pos, tmp_buf);
867                         cifs_save_resume_key(current_entry, cifsFile);
868                         break;
869                 } else
870                         current_entry =
871                                 nxt_dir_entry(current_entry, end_of_smb,
872                                         cifsFile->srch_inf.info_level);
873         }
874         kfree(tmp_buf);
875 
876 rddir2_exit:
877         free_xid(xid);
878         return rc;
879 }
880 

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