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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 or filetype(mode) changed,
 73  * then drop it and recreate it.
 74  */
 75 static void
 76 cifs_prime_dcache(struct dentry *parent, struct qstr *name,
 77                     struct cifs_fattr *fattr)
 78 {
 79         struct dentry *dentry, *alias;
 80         struct inode *inode;
 81         struct super_block *sb = parent->d_sb;
 82         struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
 83         DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
 84 
 85         cifs_dbg(FYI, "%s: for %s\n", __func__, name->name);
 86 
 87         dentry = d_hash_and_lookup(parent, name);
 88         if (!dentry) {
 89                 /*
 90                  * If we know that the inode will need to be revalidated
 91                  * immediately, then don't create a new dentry for it.
 92                  * We'll end up doing an on the wire call either way and
 93                  * this spares us an invalidation.
 94                  */
 95                 if (fattr->cf_flags & CIFS_FATTR_NEED_REVAL)
 96                         return;
 97 retry:
 98                 dentry = d_alloc_parallel(parent, name, &wq);
 99         }
100         if (IS_ERR(dentry))
101                 return;
102         if (!d_in_lookup(dentry)) {
103                 inode = d_inode(dentry);
104                 if (inode) {
105                         if (d_mountpoint(dentry)) {
106                                 dput(dentry);
107                                 return;
108                         }
109                         /*
110                          * If we're generating inode numbers, then we don't
111                          * want to clobber the existing one with the one that
112                          * the readdir code created.
113                          */
114                         if (!(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM))
115                                 fattr->cf_uniqueid = CIFS_I(inode)->uniqueid;
116 
117                         /* update inode in place
118                          * if both i_ino and i_mode didn't change */
119                         if (CIFS_I(inode)->uniqueid == fattr->cf_uniqueid &&
120                             (inode->i_mode & S_IFMT) ==
121                             (fattr->cf_mode & S_IFMT)) {
122                                 cifs_fattr_to_inode(inode, fattr);
123                                 dput(dentry);
124                                 return;
125                         }
126                 }
127                 d_invalidate(dentry);
128                 dput(dentry);
129                 goto retry;
130         } else {
131                 inode = cifs_iget(sb, fattr);
132                 if (!inode)
133                         inode = ERR_PTR(-ENOMEM);
134                 alias = d_splice_alias(inode, dentry);
135                 d_lookup_done(dentry);
136                 if (alias && !IS_ERR(alias))
137                         dput(alias);
138         }
139         dput(dentry);
140 }
141 
142 static void
143 cifs_fill_common_info(struct cifs_fattr *fattr, struct cifs_sb_info *cifs_sb)
144 {
145         fattr->cf_uid = cifs_sb->mnt_uid;
146         fattr->cf_gid = cifs_sb->mnt_gid;
147 
148         if (fattr->cf_cifsattrs & ATTR_DIRECTORY) {
149                 fattr->cf_mode = S_IFDIR | cifs_sb->mnt_dir_mode;
150                 fattr->cf_dtype = DT_DIR;
151         } else {
152                 fattr->cf_mode = S_IFREG | cifs_sb->mnt_file_mode;
153                 fattr->cf_dtype = DT_REG;
154         }
155 
156         /*
157          * We need to revalidate it further to make a decision about whether it
158          * is a symbolic link, DFS referral or a reparse point with a direct
159          * access like junctions, deduplicated files, NFS symlinks.
160          */
161         if (fattr->cf_cifsattrs & ATTR_REPARSE)
162                 fattr->cf_flags |= CIFS_FATTR_NEED_REVAL;
163 
164         /* non-unix readdir doesn't provide nlink */
165         fattr->cf_flags |= CIFS_FATTR_UNKNOWN_NLINK;
166 
167         if (fattr->cf_cifsattrs & ATTR_READONLY)
168                 fattr->cf_mode &= ~S_IWUGO;
169 
170         /*
171          * We of course don't get ACL info in FIND_FIRST/NEXT results, so
172          * mark it for revalidation so that "ls -l" will look right. It might
173          * be super-slow, but if we don't do this then the ownership of files
174          * may look wrong since the inodes may not have timed out by the time
175          * "ls" does a stat() call on them.
176          */
177         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_ACL)
178                 fattr->cf_flags |= CIFS_FATTR_NEED_REVAL;
179 
180         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_UNX_EMUL &&
181             fattr->cf_cifsattrs & ATTR_SYSTEM) {
182                 if (fattr->cf_eof == 0)  {
183                         fattr->cf_mode &= ~S_IFMT;
184                         fattr->cf_mode |= S_IFIFO;
185                         fattr->cf_dtype = DT_FIFO;
186                 } else {
187                         /*
188                          * trying to get the type and mode via SFU can be slow,
189                          * so just call those regular files for now, and mark
190                          * for reval
191                          */
192                         fattr->cf_flags |= CIFS_FATTR_NEED_REVAL;
193                 }
194         }
195 }
196 
197 void
198 cifs_dir_info_to_fattr(struct cifs_fattr *fattr, FILE_DIRECTORY_INFO *info,
199                        struct cifs_sb_info *cifs_sb)
200 {
201         memset(fattr, 0, sizeof(*fattr));
202         fattr->cf_cifsattrs = le32_to_cpu(info->ExtFileAttributes);
203         fattr->cf_eof = le64_to_cpu(info->EndOfFile);
204         fattr->cf_bytes = le64_to_cpu(info->AllocationSize);
205         fattr->cf_createtime = le64_to_cpu(info->CreationTime);
206         fattr->cf_atime = cifs_NTtimeToUnix(info->LastAccessTime);
207         fattr->cf_ctime = cifs_NTtimeToUnix(info->ChangeTime);
208         fattr->cf_mtime = cifs_NTtimeToUnix(info->LastWriteTime);
209 
210         cifs_fill_common_info(fattr, cifs_sb);
211 }
212 
213 static void
214 cifs_std_info_to_fattr(struct cifs_fattr *fattr, FIND_FILE_STANDARD_INFO *info,
215                        struct cifs_sb_info *cifs_sb)
216 {
217         int offset = cifs_sb_master_tcon(cifs_sb)->ses->server->timeAdj;
218 
219         memset(fattr, 0, sizeof(*fattr));
220         fattr->cf_atime = cnvrtDosUnixTm(info->LastAccessDate,
221                                             info->LastAccessTime, offset);
222         fattr->cf_ctime = cnvrtDosUnixTm(info->LastWriteDate,
223                                             info->LastWriteTime, offset);
224         fattr->cf_mtime = cnvrtDosUnixTm(info->LastWriteDate,
225                                             info->LastWriteTime, offset);
226 
227         fattr->cf_cifsattrs = le16_to_cpu(info->Attributes);
228         fattr->cf_bytes = le32_to_cpu(info->AllocationSize);
229         fattr->cf_eof = le32_to_cpu(info->DataSize);
230 
231         cifs_fill_common_info(fattr, cifs_sb);
232 }
233 
234 /* BB eventually need to add the following helper function to
235       resolve NT_STATUS_STOPPED_ON_SYMLINK return code when
236       we try to do FindFirst on (NTFS) directory symlinks */
237 /*
238 int get_symlink_reparse_path(char *full_path, struct cifs_sb_info *cifs_sb,
239                              unsigned int xid)
240 {
241         __u16 fid;
242         int len;
243         int oplock = 0;
244         int rc;
245         struct cifs_tcon *ptcon = cifs_sb_tcon(cifs_sb);
246         char *tmpbuffer;
247 
248         rc = CIFSSMBOpen(xid, ptcon, full_path, FILE_OPEN, GENERIC_READ,
249                         OPEN_REPARSE_POINT, &fid, &oplock, NULL,
250                         cifs_sb->local_nls,
251                         cifs_remap(cifs_sb);
252         if (!rc) {
253                 tmpbuffer = kmalloc(maxpath);
254                 rc = CIFSSMBQueryReparseLinkInfo(xid, ptcon, full_path,
255                                 tmpbuffer,
256                                 maxpath -1,
257                                 fid,
258                                 cifs_sb->local_nls);
259                 if (CIFSSMBClose(xid, ptcon, fid)) {
260                         cifs_dbg(FYI, "Error closing temporary reparsepoint open\n");
261                 }
262         }
263 }
264  */
265 
266 static int
267 initiate_cifs_search(const unsigned int xid, struct file *file)
268 {
269         __u16 search_flags;
270         int rc = 0;
271         char *full_path = NULL;
272         struct cifsFileInfo *cifsFile;
273         struct cifs_sb_info *cifs_sb = CIFS_FILE_SB(file);
274         struct tcon_link *tlink = NULL;
275         struct cifs_tcon *tcon;
276         struct TCP_Server_Info *server;
277 
278         if (file->private_data == NULL) {
279                 tlink = cifs_sb_tlink(cifs_sb);
280                 if (IS_ERR(tlink))
281                         return PTR_ERR(tlink);
282 
283                 cifsFile = kzalloc(sizeof(struct cifsFileInfo), GFP_KERNEL);
284                 if (cifsFile == NULL) {
285                         rc = -ENOMEM;
286                         goto error_exit;
287                 }
288                 spin_lock_init(&cifsFile->file_info_lock);
289                 file->private_data = cifsFile;
290                 cifsFile->tlink = cifs_get_tlink(tlink);
291                 tcon = tlink_tcon(tlink);
292         } else {
293                 cifsFile = file->private_data;
294                 tcon = tlink_tcon(cifsFile->tlink);
295         }
296 
297         server = tcon->ses->server;
298 
299         if (!server->ops->query_dir_first) {
300                 rc = -ENOSYS;
301                 goto error_exit;
302         }
303 
304         cifsFile->invalidHandle = true;
305         cifsFile->srch_inf.endOfSearch = false;
306 
307         full_path = build_path_from_dentry(file_dentry(file));
308         if (full_path == NULL) {
309                 rc = -ENOMEM;
310                 goto error_exit;
311         }
312 
313         cifs_dbg(FYI, "Full path: %s start at: %lld\n", full_path, file->f_pos);
314 
315 ffirst_retry:
316         /* test for Unix extensions */
317         /* but now check for them on the share/mount not on the SMB session */
318         /* if (cap_unix(tcon->ses) { */
319         if (tcon->unix_ext)
320                 cifsFile->srch_inf.info_level = SMB_FIND_FILE_UNIX;
321         else if ((tcon->ses->capabilities &
322                   tcon->ses->server->vals->cap_nt_find) == 0) {
323                 cifsFile->srch_inf.info_level = SMB_FIND_FILE_INFO_STANDARD;
324         } else if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM) {
325                 cifsFile->srch_inf.info_level = SMB_FIND_FILE_ID_FULL_DIR_INFO;
326         } else /* not srvinos - BB fixme add check for backlevel? */ {
327                 cifsFile->srch_inf.info_level = SMB_FIND_FILE_DIRECTORY_INFO;
328         }
329 
330         search_flags = CIFS_SEARCH_CLOSE_AT_END | CIFS_SEARCH_RETURN_RESUME;
331         if (backup_cred(cifs_sb))
332                 search_flags |= CIFS_SEARCH_BACKUP_SEARCH;
333 
334         rc = server->ops->query_dir_first(xid, tcon, full_path, cifs_sb,
335                                           &cifsFile->fid, search_flags,
336                                           &cifsFile->srch_inf);
337 
338         if (rc == 0)
339                 cifsFile->invalidHandle = false;
340         /* BB add following call to handle readdir on new NTFS symlink errors
341         else if STATUS_STOPPED_ON_SYMLINK
342                 call get_symlink_reparse_path and retry with new path */
343         else if ((rc == -EOPNOTSUPP) &&
344                 (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM)) {
345                 cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_SERVER_INUM;
346                 goto ffirst_retry;
347         }
348 error_exit:
349         kfree(full_path);
350         cifs_put_tlink(tlink);
351         return rc;
352 }
353 
354 /* return length of unicode string in bytes */
355 static int cifs_unicode_bytelen(const char *str)
356 {
357         int len;
358         const __le16 *ustr = (const __le16 *)str;
359 
360         for (len = 0; len <= PATH_MAX; len++) {
361                 if (ustr[len] == 0)
362                         return len << 1;
363         }
364         cifs_dbg(FYI, "Unicode string longer than PATH_MAX found\n");
365         return len << 1;
366 }
367 
368 static char *nxt_dir_entry(char *old_entry, char *end_of_smb, int level)
369 {
370         char *new_entry;
371         FILE_DIRECTORY_INFO *pDirInfo = (FILE_DIRECTORY_INFO *)old_entry;
372 
373         if (level == SMB_FIND_FILE_INFO_STANDARD) {
374                 FIND_FILE_STANDARD_INFO *pfData;
375                 pfData = (FIND_FILE_STANDARD_INFO *)pDirInfo;
376 
377                 new_entry = old_entry + sizeof(FIND_FILE_STANDARD_INFO) +
378                                 pfData->FileNameLength;
379         } else {
380                 u32 next_offset = le32_to_cpu(pDirInfo->NextEntryOffset);
381 
382                 if (old_entry + next_offset < old_entry) {
383                         cifs_dbg(VFS, "invalid offset %u\n", next_offset);
384                         return NULL;
385                 }
386                 new_entry = old_entry + next_offset;
387         }
388         cifs_dbg(FYI, "new entry %p old entry %p\n", new_entry, old_entry);
389         /* validate that new_entry is not past end of SMB */
390         if (new_entry >= end_of_smb) {
391                 cifs_dbg(VFS, "search entry %p began after end of SMB %p old entry %p\n",
392                          new_entry, end_of_smb, old_entry);
393                 return NULL;
394         } else if (((level == SMB_FIND_FILE_INFO_STANDARD) &&
395                     (new_entry + sizeof(FIND_FILE_STANDARD_INFO) > end_of_smb))
396                   || ((level != SMB_FIND_FILE_INFO_STANDARD) &&
397                    (new_entry + sizeof(FILE_DIRECTORY_INFO) > end_of_smb)))  {
398                 cifs_dbg(VFS, "search entry %p extends after end of SMB %p\n",
399                          new_entry, end_of_smb);
400                 return NULL;
401         } else
402                 return new_entry;
403 
404 }
405 
406 struct cifs_dirent {
407         const char      *name;
408         size_t          namelen;
409         u32             resume_key;
410         u64             ino;
411 };
412 
413 static void cifs_fill_dirent_unix(struct cifs_dirent *de,
414                 const FILE_UNIX_INFO *info, bool is_unicode)
415 {
416         de->name = &info->FileName[0];
417         if (is_unicode)
418                 de->namelen = cifs_unicode_bytelen(de->name);
419         else
420                 de->namelen = strnlen(de->name, PATH_MAX);
421         de->resume_key = info->ResumeKey;
422         de->ino = le64_to_cpu(info->basic.UniqueId);
423 }
424 
425 static void cifs_fill_dirent_dir(struct cifs_dirent *de,
426                 const FILE_DIRECTORY_INFO *info)
427 {
428         de->name = &info->FileName[0];
429         de->namelen = le32_to_cpu(info->FileNameLength);
430         de->resume_key = info->FileIndex;
431 }
432 
433 static void cifs_fill_dirent_full(struct cifs_dirent *de,
434                 const FILE_FULL_DIRECTORY_INFO *info)
435 {
436         de->name = &info->FileName[0];
437         de->namelen = le32_to_cpu(info->FileNameLength);
438         de->resume_key = info->FileIndex;
439 }
440 
441 static void cifs_fill_dirent_search(struct cifs_dirent *de,
442                 const SEARCH_ID_FULL_DIR_INFO *info)
443 {
444         de->name = &info->FileName[0];
445         de->namelen = le32_to_cpu(info->FileNameLength);
446         de->resume_key = info->FileIndex;
447         de->ino = le64_to_cpu(info->UniqueId);
448 }
449 
450 static void cifs_fill_dirent_both(struct cifs_dirent *de,
451                 const FILE_BOTH_DIRECTORY_INFO *info)
452 {
453         de->name = &info->FileName[0];
454         de->namelen = le32_to_cpu(info->FileNameLength);
455         de->resume_key = info->FileIndex;
456 }
457 
458 static void cifs_fill_dirent_std(struct cifs_dirent *de,
459                 const FIND_FILE_STANDARD_INFO *info)
460 {
461         de->name = &info->FileName[0];
462         /* one byte length, no endianess conversion */
463         de->namelen = info->FileNameLength;
464         de->resume_key = info->ResumeKey;
465 }
466 
467 static int cifs_fill_dirent(struct cifs_dirent *de, const void *info,
468                 u16 level, bool is_unicode)
469 {
470         memset(de, 0, sizeof(*de));
471 
472         switch (level) {
473         case SMB_FIND_FILE_UNIX:
474                 cifs_fill_dirent_unix(de, info, is_unicode);
475                 break;
476         case SMB_FIND_FILE_DIRECTORY_INFO:
477                 cifs_fill_dirent_dir(de, info);
478                 break;
479         case SMB_FIND_FILE_FULL_DIRECTORY_INFO:
480                 cifs_fill_dirent_full(de, info);
481                 break;
482         case SMB_FIND_FILE_ID_FULL_DIR_INFO:
483                 cifs_fill_dirent_search(de, info);
484                 break;
485         case SMB_FIND_FILE_BOTH_DIRECTORY_INFO:
486                 cifs_fill_dirent_both(de, info);
487                 break;
488         case SMB_FIND_FILE_INFO_STANDARD:
489                 cifs_fill_dirent_std(de, info);
490                 break;
491         default:
492                 cifs_dbg(FYI, "Unknown findfirst level %d\n", level);
493                 return -EINVAL;
494         }
495 
496         return 0;
497 }
498 
499 #define UNICODE_DOT cpu_to_le16(0x2e)
500 
501 /* return 0 if no match and 1 for . (current directory) and 2 for .. (parent) */
502 static int cifs_entry_is_dot(struct cifs_dirent *de, bool is_unicode)
503 {
504         int rc = 0;
505 
506         if (!de->name)
507                 return 0;
508 
509         if (is_unicode) {
510                 __le16 *ufilename = (__le16 *)de->name;
511                 if (de->namelen == 2) {
512                         /* check for . */
513                         if (ufilename[0] == UNICODE_DOT)
514                                 rc = 1;
515                 } else if (de->namelen == 4) {
516                         /* check for .. */
517                         if (ufilename[0] == UNICODE_DOT &&
518                             ufilename[1] == UNICODE_DOT)
519                                 rc = 2;
520                 }
521         } else /* ASCII */ {
522                 if (de->namelen == 1) {
523                         if (de->name[0] == '.')
524                                 rc = 1;
525                 } else if (de->namelen == 2) {
526                         if (de->name[0] == '.' && de->name[1] == '.')
527                                 rc = 2;
528                 }
529         }
530 
531         return rc;
532 }
533 
534 /* Check if directory that we are searching has changed so we can decide
535    whether we can use the cached search results from the previous search */
536 static int is_dir_changed(struct file *file)
537 {
538         struct inode *inode = file_inode(file);
539         struct cifsInodeInfo *cifsInfo = CIFS_I(inode);
540 
541         if (cifsInfo->time == 0)
542                 return 1; /* directory was changed, perhaps due to unlink */
543         else
544                 return 0;
545 
546 }
547 
548 static int cifs_save_resume_key(const char *current_entry,
549         struct cifsFileInfo *file_info)
550 {
551         struct cifs_dirent de;
552         int rc;
553 
554         rc = cifs_fill_dirent(&de, current_entry, file_info->srch_inf.info_level,
555                               file_info->srch_inf.unicode);
556         if (!rc) {
557                 file_info->srch_inf.presume_name = de.name;
558                 file_info->srch_inf.resume_name_len = de.namelen;
559                 file_info->srch_inf.resume_key = de.resume_key;
560         }
561         return rc;
562 }
563 
564 /*
565  * Find the corresponding entry in the search. Note that the SMB server returns
566  * search entries for . and .. which complicates logic here if we choose to
567  * parse for them and we do not assume that they are located in the findfirst
568  * return buffer. We start counting in the buffer with entry 2 and increment for
569  * every entry (do not increment for . or .. entry).
570  */
571 static int
572 find_cifs_entry(const unsigned int xid, struct cifs_tcon *tcon, loff_t pos,
573                 struct file *file, char **current_entry, int *num_to_ret)
574 {
575         __u16 search_flags;
576         int rc = 0;
577         int pos_in_buf = 0;
578         loff_t first_entry_in_buffer;
579         loff_t index_to_find = pos;
580         struct cifsFileInfo *cfile = file->private_data;
581         struct cifs_sb_info *cifs_sb = CIFS_FILE_SB(file);
582         struct TCP_Server_Info *server = tcon->ses->server;
583         /* check if index in the buffer */
584 
585         if (!server->ops->query_dir_first || !server->ops->query_dir_next)
586                 return -ENOSYS;
587 
588         if ((cfile == NULL) || (current_entry == NULL) || (num_to_ret == NULL))
589                 return -ENOENT;
590 
591         *current_entry = NULL;
592         first_entry_in_buffer = cfile->srch_inf.index_of_last_entry -
593                                         cfile->srch_inf.entries_in_buffer;
594 
595         /*
596          * If first entry in buf is zero then is first buffer
597          * in search response data which means it is likely . and ..
598          * will be in this buffer, although some servers do not return
599          * . and .. for the root of a drive and for those we need
600          * to start two entries earlier.
601          */
602 
603         dump_cifs_file_struct(file, "In fce ");
604         if (((index_to_find < cfile->srch_inf.index_of_last_entry) &&
605              is_dir_changed(file)) || (index_to_find < first_entry_in_buffer)) {
606                 /* close and restart search */
607                 cifs_dbg(FYI, "search backing up - close and restart search\n");
608                 spin_lock(&cfile->file_info_lock);
609                 if (server->ops->dir_needs_close(cfile)) {
610                         cfile->invalidHandle = true;
611                         spin_unlock(&cfile->file_info_lock);
612                         if (server->ops->close_dir)
613                                 server->ops->close_dir(xid, tcon, &cfile->fid);
614                 } else
615                         spin_unlock(&cfile->file_info_lock);
616                 if (cfile->srch_inf.ntwrk_buf_start) {
617                         cifs_dbg(FYI, "freeing SMB ff cache buf on search rewind\n");
618                         if (cfile->srch_inf.smallBuf)
619                                 cifs_small_buf_release(cfile->srch_inf.
620                                                 ntwrk_buf_start);
621                         else
622                                 cifs_buf_release(cfile->srch_inf.
623                                                 ntwrk_buf_start);
624                         cfile->srch_inf.ntwrk_buf_start = NULL;
625                 }
626                 rc = initiate_cifs_search(xid, file);
627                 if (rc) {
628                         cifs_dbg(FYI, "error %d reinitiating a search on rewind\n",
629                                  rc);
630                         return rc;
631                 }
632                 /* FindFirst/Next set last_entry to NULL on malformed reply */
633                 if (cfile->srch_inf.last_entry)
634                         cifs_save_resume_key(cfile->srch_inf.last_entry, cfile);
635         }
636 
637         search_flags = CIFS_SEARCH_CLOSE_AT_END | CIFS_SEARCH_RETURN_RESUME;
638         if (backup_cred(cifs_sb))
639                 search_flags |= CIFS_SEARCH_BACKUP_SEARCH;
640 
641         while ((index_to_find >= cfile->srch_inf.index_of_last_entry) &&
642                (rc == 0) && !cfile->srch_inf.endOfSearch) {
643                 cifs_dbg(FYI, "calling findnext2\n");
644                 rc = server->ops->query_dir_next(xid, tcon, &cfile->fid,
645                                                  search_flags,
646                                                  &cfile->srch_inf);
647                 /* FindFirst/Next set last_entry to NULL on malformed reply */
648                 if (cfile->srch_inf.last_entry)
649                         cifs_save_resume_key(cfile->srch_inf.last_entry, cfile);
650                 if (rc)
651                         return -ENOENT;
652         }
653         if (index_to_find < cfile->srch_inf.index_of_last_entry) {
654                 /* we found the buffer that contains the entry */
655                 /* scan and find it */
656                 int i;
657                 char *cur_ent;
658                 char *end_of_smb;
659 
660                 if (cfile->srch_inf.ntwrk_buf_start == NULL) {
661                         cifs_dbg(VFS, "ntwrk_buf_start is NULL during readdir\n");
662                         return -EIO;
663                 }
664 
665                 end_of_smb = cfile->srch_inf.ntwrk_buf_start +
666                         server->ops->calc_smb_size(
667                                         cfile->srch_inf.ntwrk_buf_start,
668                                         server);
669 
670                 cur_ent = cfile->srch_inf.srch_entries_start;
671                 first_entry_in_buffer = cfile->srch_inf.index_of_last_entry
672                                         - cfile->srch_inf.entries_in_buffer;
673                 pos_in_buf = index_to_find - first_entry_in_buffer;
674                 cifs_dbg(FYI, "found entry - pos_in_buf %d\n", pos_in_buf);
675 
676                 for (i = 0; (i < (pos_in_buf)) && (cur_ent != NULL); i++) {
677                         /* go entry by entry figuring out which is first */
678                         cur_ent = nxt_dir_entry(cur_ent, end_of_smb,
679                                                 cfile->srch_inf.info_level);
680                 }
681                 if ((cur_ent == NULL) && (i < pos_in_buf)) {
682                         /* BB fixme - check if we should flag this error */
683                         cifs_dbg(VFS, "reached end of buf searching for pos in buf %d index to find %lld rc %d\n",
684                                  pos_in_buf, index_to_find, rc);
685                 }
686                 rc = 0;
687                 *current_entry = cur_ent;
688         } else {
689                 cifs_dbg(FYI, "index not in buffer - could not findnext into it\n");
690                 return 0;
691         }
692 
693         if (pos_in_buf >= cfile->srch_inf.entries_in_buffer) {
694                 cifs_dbg(FYI, "can not return entries pos_in_buf beyond last\n");
695                 *num_to_ret = 0;
696         } else
697                 *num_to_ret = cfile->srch_inf.entries_in_buffer - pos_in_buf;
698 
699         return rc;
700 }
701 
702 static int cifs_filldir(char *find_entry, struct file *file,
703                 struct dir_context *ctx,
704                 char *scratch_buf, unsigned int max_len)
705 {
706         struct cifsFileInfo *file_info = file->private_data;
707         struct super_block *sb = file_inode(file)->i_sb;
708         struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
709         struct cifs_dirent de = { NULL, };
710         struct cifs_fattr fattr;
711         struct qstr name;
712         int rc = 0;
713         ino_t ino;
714 
715         rc = cifs_fill_dirent(&de, find_entry, file_info->srch_inf.info_level,
716                               file_info->srch_inf.unicode);
717         if (rc)
718                 return rc;
719 
720         if (de.namelen > max_len) {
721                 cifs_dbg(VFS, "bad search response length %zd past smb end\n",
722                          de.namelen);
723                 return -EINVAL;
724         }
725 
726         /* skip . and .. since we added them first */
727         if (cifs_entry_is_dot(&de, file_info->srch_inf.unicode))
728                 return 0;
729 
730         if (file_info->srch_inf.unicode) {
731                 struct nls_table *nlt = cifs_sb->local_nls;
732                 int map_type;
733 
734                 map_type = cifs_remap(cifs_sb);
735                 name.name = scratch_buf;
736                 name.len =
737                         cifs_from_utf16((char *)name.name, (__le16 *)de.name,
738                                         UNICODE_NAME_MAX,
739                                         min_t(size_t, de.namelen,
740                                               (size_t)max_len), nlt, map_type);
741                 name.len -= nls_nullsize(nlt);
742         } else {
743                 name.name = de.name;
744                 name.len = de.namelen;
745         }
746 
747         switch (file_info->srch_inf.info_level) {
748         case SMB_FIND_FILE_UNIX:
749                 cifs_unix_basic_to_fattr(&fattr,
750                                          &((FILE_UNIX_INFO *)find_entry)->basic,
751                                          cifs_sb);
752                 break;
753         case SMB_FIND_FILE_INFO_STANDARD:
754                 cifs_std_info_to_fattr(&fattr,
755                                        (FIND_FILE_STANDARD_INFO *)find_entry,
756                                        cifs_sb);
757                 break;
758         default:
759                 cifs_dir_info_to_fattr(&fattr,
760                                        (FILE_DIRECTORY_INFO *)find_entry,
761                                        cifs_sb);
762                 break;
763         }
764 
765         if (de.ino && (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM)) {
766                 fattr.cf_uniqueid = de.ino;
767         } else {
768                 fattr.cf_uniqueid = iunique(sb, ROOT_I);
769                 cifs_autodisable_serverino(cifs_sb);
770         }
771 
772         if ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS) &&
773             couldbe_mf_symlink(&fattr))
774                 /*
775                  * trying to get the type and mode can be slow,
776                  * so just call those regular files for now, and mark
777                  * for reval
778                  */
779                 fattr.cf_flags |= CIFS_FATTR_NEED_REVAL;
780 
781         cifs_prime_dcache(file_dentry(file), &name, &fattr);
782 
783         ino = cifs_uniqueid_to_ino_t(fattr.cf_uniqueid);
784         return !dir_emit(ctx, name.name, name.len, ino, fattr.cf_dtype);
785 }
786 
787 
788 int cifs_readdir(struct file *file, struct dir_context *ctx)
789 {
790         int rc = 0;
791         unsigned int xid;
792         int i;
793         struct cifs_tcon *tcon;
794         struct cifsFileInfo *cifsFile = NULL;
795         char *current_entry;
796         int num_to_fill = 0;
797         char *tmp_buf = NULL;
798         char *end_of_smb;
799         unsigned int max_len;
800 
801         xid = get_xid();
802 
803         /*
804          * Ensure FindFirst doesn't fail before doing filldir() for '.' and
805          * '..'. Otherwise we won't be able to notify VFS in case of failure.
806          */
807         if (file->private_data == NULL) {
808                 rc = initiate_cifs_search(xid, file);
809                 cifs_dbg(FYI, "initiate cifs search rc %d\n", rc);
810                 if (rc)
811                         goto rddir2_exit;
812         }
813 
814         if (!dir_emit_dots(file, ctx))
815                 goto rddir2_exit;
816 
817         /* 1) If search is active,
818                 is in current search buffer?
819                 if it before then restart search
820                 if after then keep searching till find it */
821 
822         cifsFile = file->private_data;
823         if (cifsFile->srch_inf.endOfSearch) {
824                 if (cifsFile->srch_inf.emptyDir) {
825                         cifs_dbg(FYI, "End of search, empty dir\n");
826                         rc = 0;
827                         goto rddir2_exit;
828                 }
829         } /* else {
830                 cifsFile->invalidHandle = true;
831                 tcon->ses->server->close(xid, tcon, &cifsFile->fid);
832         } */
833 
834         tcon = tlink_tcon(cifsFile->tlink);
835         rc = find_cifs_entry(xid, tcon, ctx->pos, file, &current_entry,
836                              &num_to_fill);
837         if (rc) {
838                 cifs_dbg(FYI, "fce error %d\n", rc);
839                 goto rddir2_exit;
840         } else if (current_entry != NULL) {
841                 cifs_dbg(FYI, "entry %lld found\n", ctx->pos);
842         } else {
843                 cifs_dbg(FYI, "could not find entry\n");
844                 goto rddir2_exit;
845         }
846         cifs_dbg(FYI, "loop through %d times filling dir for net buf %p\n",
847                  num_to_fill, cifsFile->srch_inf.ntwrk_buf_start);
848         max_len = tcon->ses->server->ops->calc_smb_size(
849                         cifsFile->srch_inf.ntwrk_buf_start,
850                         tcon->ses->server);
851         end_of_smb = cifsFile->srch_inf.ntwrk_buf_start + max_len;
852 
853         tmp_buf = kmalloc(UNICODE_NAME_MAX, GFP_KERNEL);
854         if (tmp_buf == NULL) {
855                 rc = -ENOMEM;
856                 goto rddir2_exit;
857         }
858 
859         for (i = 0; i < num_to_fill; i++) {
860                 if (current_entry == NULL) {
861                         /* evaluate whether this case is an error */
862                         cifs_dbg(VFS, "past SMB end,  num to fill %d i %d\n",
863                                  num_to_fill, i);
864                         break;
865                 }
866                 /*
867                  * if buggy server returns . and .. late do we want to
868                  * check for that here?
869                  */
870                 *tmp_buf = 0;
871                 rc = cifs_filldir(current_entry, file, ctx,
872                                   tmp_buf, max_len);
873                 if (rc) {
874                         if (rc > 0)
875                                 rc = 0;
876                         break;
877                 }
878 
879                 ctx->pos++;
880                 if (ctx->pos ==
881                         cifsFile->srch_inf.index_of_last_entry) {
882                         cifs_dbg(FYI, "last entry in buf at pos %lld %s\n",
883                                  ctx->pos, tmp_buf);
884                         cifs_save_resume_key(current_entry, cifsFile);
885                         break;
886                 } else
887                         current_entry =
888                                 nxt_dir_entry(current_entry, end_of_smb,
889                                         cifsFile->srch_inf.info_level);
890         }
891         kfree(tmp_buf);
892 
893 rddir2_exit:
894         free_xid(xid);
895         return rc;
896 }
897 

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