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
  44static 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
  63static 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 */
  74static void
  75cifs_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);
 133out:
 134        dput(dentry);
 135}
 136
 137static void
 138cifs_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
 192void
 193cifs_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
 208static void
 209cifs_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/*
 233int 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
 261static int
 262initiate_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                file->private_data = cifsFile;
 284                cifsFile->tlink = cifs_get_tlink(tlink);
 285                tcon = tlink_tcon(tlink);
 286        } else {
 287                cifsFile = file->private_data;
 288                tcon = tlink_tcon(cifsFile->tlink);
 289        }
 290
 291        server = tcon->ses->server;
 292
 293        if (!server->ops->query_dir_first) {
 294                rc = -ENOSYS;
 295                goto error_exit;
 296        }
 297
 298        cifsFile->invalidHandle = true;
 299        cifsFile->srch_inf.endOfSearch = false;
 300
 301        full_path = build_path_from_dentry(file->f_path.dentry);
 302        if (full_path == NULL) {
 303                rc = -ENOMEM;
 304                goto error_exit;
 305        }
 306
 307        cifs_dbg(FYI, "Full path: %s start at: %lld\n", full_path, file->f_pos);
 308
 309ffirst_retry:
 310        /* test for Unix extensions */
 311        /* but now check for them on the share/mount not on the SMB session */
 312        /* if (cap_unix(tcon->ses) { */
 313        if (tcon->unix_ext)
 314                cifsFile->srch_inf.info_level = SMB_FIND_FILE_UNIX;
 315        else if ((tcon->ses->capabilities &
 316                  tcon->ses->server->vals->cap_nt_find) == 0) {
 317                cifsFile->srch_inf.info_level = SMB_FIND_FILE_INFO_STANDARD;
 318        } else if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM) {
 319                cifsFile->srch_inf.info_level = SMB_FIND_FILE_ID_FULL_DIR_INFO;
 320        } else /* not srvinos - BB fixme add check for backlevel? */ {
 321                cifsFile->srch_inf.info_level = SMB_FIND_FILE_DIRECTORY_INFO;
 322        }
 323
 324        search_flags = CIFS_SEARCH_CLOSE_AT_END | CIFS_SEARCH_RETURN_RESUME;
 325        if (backup_cred(cifs_sb))
 326                search_flags |= CIFS_SEARCH_BACKUP_SEARCH;
 327
 328        rc = server->ops->query_dir_first(xid, tcon, full_path, cifs_sb,
 329                                          &cifsFile->fid, search_flags,
 330                                          &cifsFile->srch_inf);
 331
 332        if (rc == 0)
 333                cifsFile->invalidHandle = false;
 334        /* BB add following call to handle readdir on new NTFS symlink errors
 335        else if STATUS_STOPPED_ON_SYMLINK
 336                call get_symlink_reparse_path and retry with new path */
 337        else if ((rc == -EOPNOTSUPP) &&
 338                (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM)) {
 339                cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_SERVER_INUM;
 340                goto ffirst_retry;
 341        }
 342error_exit:
 343        kfree(full_path);
 344        cifs_put_tlink(tlink);
 345        return rc;
 346}
 347
 348/* return length of unicode string in bytes */
 349static int cifs_unicode_bytelen(const char *str)
 350{
 351        int len;
 352        const __le16 *ustr = (const __le16 *)str;
 353
 354        for (len = 0; len <= PATH_MAX; len++) {
 355                if (ustr[len] == 0)
 356                        return len << 1;
 357        }
 358        cifs_dbg(FYI, "Unicode string longer than PATH_MAX found\n");
 359        return len << 1;
 360}
 361
 362static char *nxt_dir_entry(char *old_entry, char *end_of_smb, int level)
 363{
 364        char *new_entry;
 365        FILE_DIRECTORY_INFO *pDirInfo = (FILE_DIRECTORY_INFO *)old_entry;
 366
 367        if (level == SMB_FIND_FILE_INFO_STANDARD) {
 368                FIND_FILE_STANDARD_INFO *pfData;
 369                pfData = (FIND_FILE_STANDARD_INFO *)pDirInfo;
 370
 371                new_entry = old_entry + sizeof(FIND_FILE_STANDARD_INFO) +
 372                                pfData->FileNameLength;
 373        } else
 374                new_entry = old_entry + le32_to_cpu(pDirInfo->NextEntryOffset);
 375        cifs_dbg(FYI, "new entry %p old entry %p\n", new_entry, old_entry);
 376        /* validate that new_entry is not past end of SMB */
 377        if (new_entry >= end_of_smb) {
 378                cifs_dbg(VFS, "search entry %p began after end of SMB %p old entry %p\n",
 379                         new_entry, end_of_smb, old_entry);
 380                return NULL;
 381        } else if (((level == SMB_FIND_FILE_INFO_STANDARD) &&
 382                    (new_entry + sizeof(FIND_FILE_STANDARD_INFO) > end_of_smb))
 383                  || ((level != SMB_FIND_FILE_INFO_STANDARD) &&
 384                   (new_entry + sizeof(FILE_DIRECTORY_INFO) > end_of_smb)))  {
 385                cifs_dbg(VFS, "search entry %p extends after end of SMB %p\n",
 386                         new_entry, end_of_smb);
 387                return NULL;
 388        } else
 389                return new_entry;
 390
 391}
 392
 393struct cifs_dirent {
 394        const char      *name;
 395        size_t          namelen;
 396        u32             resume_key;
 397        u64             ino;
 398};
 399
 400static void cifs_fill_dirent_unix(struct cifs_dirent *de,
 401                const FILE_UNIX_INFO *info, bool is_unicode)
 402{
 403        de->name = &info->FileName[0];
 404        if (is_unicode)
 405                de->namelen = cifs_unicode_bytelen(de->name);
 406        else
 407                de->namelen = strnlen(de->name, PATH_MAX);
 408        de->resume_key = info->ResumeKey;
 409        de->ino = le64_to_cpu(info->basic.UniqueId);
 410}
 411
 412static void cifs_fill_dirent_dir(struct cifs_dirent *de,
 413                const FILE_DIRECTORY_INFO *info)
 414{
 415        de->name = &info->FileName[0];
 416        de->namelen = le32_to_cpu(info->FileNameLength);
 417        de->resume_key = info->FileIndex;
 418}
 419
 420static void cifs_fill_dirent_full(struct cifs_dirent *de,
 421                const FILE_FULL_DIRECTORY_INFO *info)
 422{
 423        de->name = &info->FileName[0];
 424        de->namelen = le32_to_cpu(info->FileNameLength);
 425        de->resume_key = info->FileIndex;
 426}
 427
 428static void cifs_fill_dirent_search(struct cifs_dirent *de,
 429                const SEARCH_ID_FULL_DIR_INFO *info)
 430{
 431        de->name = &info->FileName[0];
 432        de->namelen = le32_to_cpu(info->FileNameLength);
 433        de->resume_key = info->FileIndex;
 434        de->ino = le64_to_cpu(info->UniqueId);
 435}
 436
 437static void cifs_fill_dirent_both(struct cifs_dirent *de,
 438                const FILE_BOTH_DIRECTORY_INFO *info)
 439{
 440        de->name = &info->FileName[0];
 441        de->namelen = le32_to_cpu(info->FileNameLength);
 442        de->resume_key = info->FileIndex;
 443}
 444
 445static void cifs_fill_dirent_std(struct cifs_dirent *de,
 446                const FIND_FILE_STANDARD_INFO *info)
 447{
 448        de->name = &info->FileName[0];
 449        /* one byte length, no endianess conversion */
 450        de->namelen = info->FileNameLength;
 451        de->resume_key = info->ResumeKey;
 452}
 453
 454static int cifs_fill_dirent(struct cifs_dirent *de, const void *info,
 455                u16 level, bool is_unicode)
 456{
 457        memset(de, 0, sizeof(*de));
 458
 459        switch (level) {
 460        case SMB_FIND_FILE_UNIX:
 461                cifs_fill_dirent_unix(de, info, is_unicode);
 462                break;
 463        case SMB_FIND_FILE_DIRECTORY_INFO:
 464                cifs_fill_dirent_dir(de, info);
 465                break;
 466        case SMB_FIND_FILE_FULL_DIRECTORY_INFO:
 467                cifs_fill_dirent_full(de, info);
 468                break;
 469        case SMB_FIND_FILE_ID_FULL_DIR_INFO:
 470                cifs_fill_dirent_search(de, info);
 471                break;
 472        case SMB_FIND_FILE_BOTH_DIRECTORY_INFO:
 473                cifs_fill_dirent_both(de, info);
 474                break;
 475        case SMB_FIND_FILE_INFO_STANDARD:
 476                cifs_fill_dirent_std(de, info);
 477                break;
 478        default:
 479                cifs_dbg(FYI, "Unknown findfirst level %d\n", level);
 480                return -EINVAL;
 481        }
 482
 483        return 0;
 484}
 485
 486#define UNICODE_DOT cpu_to_le16(0x2e)
 487
 488/* return 0 if no match and 1 for . (current directory) and 2 for .. (parent) */
 489static int cifs_entry_is_dot(struct cifs_dirent *de, bool is_unicode)
 490{
 491        int rc = 0;
 492
 493        if (!de->name)
 494                return 0;
 495
 496        if (is_unicode) {
 497                __le16 *ufilename = (__le16 *)de->name;
 498                if (de->namelen == 2) {
 499                        /* check for . */
 500                        if (ufilename[0] == UNICODE_DOT)
 501                                rc = 1;
 502                } else if (de->namelen == 4) {
 503                        /* check for .. */
 504                        if (ufilename[0] == UNICODE_DOT &&
 505                            ufilename[1] == UNICODE_DOT)
 506                                rc = 2;
 507                }
 508        } else /* ASCII */ {
 509                if (de->namelen == 1) {
 510                        if (de->name[0] == '.')
 511                                rc = 1;
 512                } else if (de->namelen == 2) {
 513                        if (de->name[0] == '.' && de->name[1] == '.')
 514                                rc = 2;
 515                }
 516        }
 517
 518        return rc;
 519}
 520
 521/* Check if directory that we are searching has changed so we can decide
 522   whether we can use the cached search results from the previous search */
 523static int is_dir_changed(struct file *file)
 524{
 525        struct inode *inode = file_inode(file);
 526        struct cifsInodeInfo *cifsInfo = CIFS_I(inode);
 527
 528        if (cifsInfo->time == 0)
 529                return 1; /* directory was changed, perhaps due to unlink */
 530        else
 531                return 0;
 532
 533}
 534
 535static int cifs_save_resume_key(const char *current_entry,
 536        struct cifsFileInfo *file_info)
 537{
 538        struct cifs_dirent de;
 539        int rc;
 540
 541        rc = cifs_fill_dirent(&de, current_entry, file_info->srch_inf.info_level,
 542                              file_info->srch_inf.unicode);
 543        if (!rc) {
 544                file_info->srch_inf.presume_name = de.name;
 545                file_info->srch_inf.resume_name_len = de.namelen;
 546                file_info->srch_inf.resume_key = de.resume_key;
 547        }
 548        return rc;
 549}
 550
 551/*
 552 * Find the corresponding entry in the search. Note that the SMB server returns
 553 * search entries for . and .. which complicates logic here if we choose to
 554 * parse for them and we do not assume that they are located in the findfirst
 555 * return buffer. We start counting in the buffer with entry 2 and increment for
 556 * every entry (do not increment for . or .. entry).
 557 */
 558static int
 559find_cifs_entry(const unsigned int xid, struct cifs_tcon *tcon, loff_t pos,
 560                struct file *file, char **current_entry, int *num_to_ret)
 561{
 562        __u16 search_flags;
 563        int rc = 0;
 564        int pos_in_buf = 0;
 565        loff_t first_entry_in_buffer;
 566        loff_t index_to_find = pos;
 567        struct cifsFileInfo *cfile = file->private_data;
 568        struct cifs_sb_info *cifs_sb = CIFS_SB(file->f_path.dentry->d_sb);
 569        struct TCP_Server_Info *server = tcon->ses->server;
 570        /* check if index in the buffer */
 571
 572        if (!server->ops->query_dir_first || !server->ops->query_dir_next)
 573                return -ENOSYS;
 574
 575        if ((cfile == NULL) || (current_entry == NULL) || (num_to_ret == NULL))
 576                return -ENOENT;
 577
 578        *current_entry = NULL;
 579        first_entry_in_buffer = cfile->srch_inf.index_of_last_entry -
 580                                        cfile->srch_inf.entries_in_buffer;
 581
 582        /*
 583         * If first entry in buf is zero then is first buffer
 584         * in search response data which means it is likely . and ..
 585         * will be in this buffer, although some servers do not return
 586         * . and .. for the root of a drive and for those we need
 587         * to start two entries earlier.
 588         */
 589
 590        dump_cifs_file_struct(file, "In fce ");
 591        if (((index_to_find < cfile->srch_inf.index_of_last_entry) &&
 592             is_dir_changed(file)) || (index_to_find < first_entry_in_buffer)) {
 593                /* close and restart search */
 594                cifs_dbg(FYI, "search backing up - close and restart search\n");
 595                spin_lock(&cifs_file_list_lock);
 596                if (!cfile->srch_inf.endOfSearch && !cfile->invalidHandle) {
 597                        cfile->invalidHandle = true;
 598                        spin_unlock(&cifs_file_list_lock);
 599                        if (server->ops->close)
 600                                server->ops->close(xid, tcon, &cfile->fid);
 601                } else
 602                        spin_unlock(&cifs_file_list_lock);
 603                if (cfile->srch_inf.ntwrk_buf_start) {
 604                        cifs_dbg(FYI, "freeing SMB ff cache buf on search rewind\n");
 605                        if (cfile->srch_inf.smallBuf)
 606                                cifs_small_buf_release(cfile->srch_inf.
 607                                                ntwrk_buf_start);
 608                        else
 609                                cifs_buf_release(cfile->srch_inf.
 610                                                ntwrk_buf_start);
 611                        cfile->srch_inf.ntwrk_buf_start = NULL;
 612                }
 613                rc = initiate_cifs_search(xid, file);
 614                if (rc) {
 615                        cifs_dbg(FYI, "error %d reinitiating a search on rewind\n",
 616                                 rc);
 617                        return rc;
 618                }
 619                /* FindFirst/Next set last_entry to NULL on malformed reply */
 620                if (cfile->srch_inf.last_entry)
 621                        cifs_save_resume_key(cfile->srch_inf.last_entry, cfile);
 622        }
 623
 624        search_flags = CIFS_SEARCH_CLOSE_AT_END | CIFS_SEARCH_RETURN_RESUME;
 625        if (backup_cred(cifs_sb))
 626                search_flags |= CIFS_SEARCH_BACKUP_SEARCH;
 627
 628        while ((index_to_find >= cfile->srch_inf.index_of_last_entry) &&
 629               (rc == 0) && !cfile->srch_inf.endOfSearch) {
 630                cifs_dbg(FYI, "calling findnext2\n");
 631                rc = server->ops->query_dir_next(xid, tcon, &cfile->fid,
 632                                                 search_flags,
 633                                                 &cfile->srch_inf);
 634                /* FindFirst/Next set last_entry to NULL on malformed reply */
 635                if (cfile->srch_inf.last_entry)
 636                        cifs_save_resume_key(cfile->srch_inf.last_entry, cfile);
 637                if (rc)
 638                        return -ENOENT;
 639        }
 640        if (index_to_find < cfile->srch_inf.index_of_last_entry) {
 641                /* we found the buffer that contains the entry */
 642                /* scan and find it */
 643                int i;
 644                char *cur_ent;
 645                char *end_of_smb = cfile->srch_inf.ntwrk_buf_start +
 646                        server->ops->calc_smb_size(
 647                                        cfile->srch_inf.ntwrk_buf_start);
 648
 649                cur_ent = cfile->srch_inf.srch_entries_start;
 650                first_entry_in_buffer = cfile->srch_inf.index_of_last_entry
 651                                        - cfile->srch_inf.entries_in_buffer;
 652                pos_in_buf = index_to_find - first_entry_in_buffer;
 653                cifs_dbg(FYI, "found entry - pos_in_buf %d\n", pos_in_buf);
 654
 655                for (i = 0; (i < (pos_in_buf)) && (cur_ent != NULL); i++) {
 656                        /* go entry by entry figuring out which is first */
 657                        cur_ent = nxt_dir_entry(cur_ent, end_of_smb,
 658                                                cfile->srch_inf.info_level);
 659                }
 660                if ((cur_ent == NULL) && (i < pos_in_buf)) {
 661                        /* BB fixme - check if we should flag this error */
 662                        cifs_dbg(VFS, "reached end of buf searching for pos in buf %d index to find %lld rc %d\n",
 663                                 pos_in_buf, index_to_find, rc);
 664                }
 665                rc = 0;
 666                *current_entry = cur_ent;
 667        } else {
 668                cifs_dbg(FYI, "index not in buffer - could not findnext into it\n");
 669                return 0;
 670        }
 671
 672        if (pos_in_buf >= cfile->srch_inf.entries_in_buffer) {
 673                cifs_dbg(FYI, "can not return entries pos_in_buf beyond last\n");
 674                *num_to_ret = 0;
 675        } else
 676                *num_to_ret = cfile->srch_inf.entries_in_buffer - pos_in_buf;
 677
 678        return rc;
 679}
 680
 681static int cifs_filldir(char *find_entry, struct file *file,
 682                struct dir_context *ctx,
 683                char *scratch_buf, unsigned int max_len)
 684{
 685        struct cifsFileInfo *file_info = file->private_data;
 686        struct super_block *sb = file->f_path.dentry->d_sb;
 687        struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
 688        struct cifs_dirent de = { NULL, };
 689        struct cifs_fattr fattr;
 690        struct qstr name;
 691        int rc = 0;
 692        ino_t ino;
 693
 694        rc = cifs_fill_dirent(&de, find_entry, file_info->srch_inf.info_level,
 695                              file_info->srch_inf.unicode);
 696        if (rc)
 697                return rc;
 698
 699        if (de.namelen > max_len) {
 700                cifs_dbg(VFS, "bad search response length %zd past smb end\n",
 701                         de.namelen);
 702                return -EINVAL;
 703        }
 704
 705        /* skip . and .. since we added them first */
 706        if (cifs_entry_is_dot(&de, file_info->srch_inf.unicode))
 707                return 0;
 708
 709        if (file_info->srch_inf.unicode) {
 710                struct nls_table *nlt = cifs_sb->local_nls;
 711
 712                name.name = scratch_buf;
 713                name.len =
 714                        cifs_from_utf16((char *)name.name, (__le16 *)de.name,
 715                                        UNICODE_NAME_MAX,
 716                                        min_t(size_t, de.namelen,
 717                                              (size_t)max_len), nlt,
 718                                        cifs_sb->mnt_cifs_flags &
 719                                                CIFS_MOUNT_MAP_SPECIAL_CHR);
 720                name.len -= nls_nullsize(nlt);
 721        } else {
 722                name.name = de.name;
 723                name.len = de.namelen;
 724        }
 725
 726        switch (file_info->srch_inf.info_level) {
 727        case SMB_FIND_FILE_UNIX:
 728                cifs_unix_basic_to_fattr(&fattr,
 729                                         &((FILE_UNIX_INFO *)find_entry)->basic,
 730                                         cifs_sb);
 731                break;
 732        case SMB_FIND_FILE_INFO_STANDARD:
 733                cifs_std_info_to_fattr(&fattr,
 734                                       (FIND_FILE_STANDARD_INFO *)find_entry,
 735                                       cifs_sb);
 736                break;
 737        default:
 738                cifs_dir_info_to_fattr(&fattr,
 739                                       (FILE_DIRECTORY_INFO *)find_entry,
 740                                       cifs_sb);
 741                break;
 742        }
 743
 744        if (de.ino && (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM)) {
 745                fattr.cf_uniqueid = de.ino;
 746        } else {
 747                fattr.cf_uniqueid = iunique(sb, ROOT_I);
 748                cifs_autodisable_serverino(cifs_sb);
 749        }
 750
 751        if ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS) &&
 752            CIFSCouldBeMFSymlink(&fattr))
 753                /*
 754                 * trying to get the type and mode can be slow,
 755                 * so just call those regular files for now, and mark
 756                 * for reval
 757                 */
 758                fattr.cf_flags |= CIFS_FATTR_NEED_REVAL;
 759
 760        cifs_prime_dcache(file->f_dentry, &name, &fattr);
 761
 762        ino = cifs_uniqueid_to_ino_t(fattr.cf_uniqueid);
 763        return !dir_emit(ctx, name.name, name.len, ino, fattr.cf_dtype);
 764}
 765
 766
 767int cifs_readdir(struct file *file, struct dir_context *ctx)
 768{
 769        int rc = 0;
 770        unsigned int xid;
 771        int i;
 772        struct cifs_tcon *tcon;
 773        struct cifsFileInfo *cifsFile = NULL;
 774        char *current_entry;
 775        int num_to_fill = 0;
 776        char *tmp_buf = NULL;
 777        char *end_of_smb;
 778        unsigned int max_len;
 779
 780        xid = get_xid();
 781
 782        /*
 783         * Ensure FindFirst doesn't fail before doing filldir() for '.' and
 784         * '..'. Otherwise we won't be able to notify VFS in case of failure.
 785         */
 786        if (file->private_data == NULL) {
 787                rc = initiate_cifs_search(xid, file);
 788                cifs_dbg(FYI, "initiate cifs search rc %d\n", rc);
 789                if (rc)
 790                        goto rddir2_exit;
 791        }
 792
 793        if (!dir_emit_dots(file, ctx))
 794                goto rddir2_exit;
 795
 796        /* 1) If search is active,
 797                is in current search buffer?
 798                if it before then restart search
 799                if after then keep searching till find it */
 800
 801        if (file->private_data == NULL) {
 802                rc = -EINVAL;
 803                goto rddir2_exit;
 804        }
 805        cifsFile = file->private_data;
 806        if (cifsFile->srch_inf.endOfSearch) {
 807                if (cifsFile->srch_inf.emptyDir) {
 808                        cifs_dbg(FYI, "End of search, empty dir\n");
 809                        rc = 0;
 810                        goto rddir2_exit;
 811                }
 812        } /* else {
 813                cifsFile->invalidHandle = true;
 814                tcon->ses->server->close(xid, tcon, &cifsFile->fid);
 815        } */
 816
 817        tcon = tlink_tcon(cifsFile->tlink);
 818        rc = find_cifs_entry(xid, tcon, ctx->pos, file, &current_entry,
 819                             &num_to_fill);
 820        if (rc) {
 821                cifs_dbg(FYI, "fce error %d\n", rc);
 822                goto rddir2_exit;
 823        } else if (current_entry != NULL) {
 824                cifs_dbg(FYI, "entry %lld found\n", ctx->pos);
 825        } else {
 826                cifs_dbg(FYI, "could not find entry\n");
 827                goto rddir2_exit;
 828        }
 829        cifs_dbg(FYI, "loop through %d times filling dir for net buf %p\n",
 830                 num_to_fill, cifsFile->srch_inf.ntwrk_buf_start);
 831        max_len = tcon->ses->server->ops->calc_smb_size(
 832                        cifsFile->srch_inf.ntwrk_buf_start);
 833        end_of_smb = cifsFile->srch_inf.ntwrk_buf_start + max_len;
 834
 835        tmp_buf = kmalloc(UNICODE_NAME_MAX, GFP_KERNEL);
 836        if (tmp_buf == NULL) {
 837                rc = -ENOMEM;
 838                goto rddir2_exit;
 839        }
 840
 841        for (i = 0; i < num_to_fill; i++) {
 842                if (current_entry == NULL) {
 843                        /* evaluate whether this case is an error */
 844                        cifs_dbg(VFS, "past SMB end,  num to fill %d i %d\n",
 845                                 num_to_fill, i);
 846                        break;
 847                }
 848                /*
 849                 * if buggy server returns . and .. late do we want to
 850                 * check for that here?
 851                 */
 852                rc = cifs_filldir(current_entry, file, ctx,
 853                                  tmp_buf, max_len);
 854                if (rc) {
 855                        if (rc > 0)
 856                                rc = 0;
 857                        break;
 858                }
 859
 860                ctx->pos++;
 861                if (ctx->pos ==
 862                        cifsFile->srch_inf.index_of_last_entry) {
 863                        cifs_dbg(FYI, "last entry in buf at pos %lld %s\n",
 864                                 ctx->pos, tmp_buf);
 865                        cifs_save_resume_key(current_entry, cifsFile);
 866                        break;
 867                } else
 868                        current_entry =
 869                                nxt_dir_entry(current_entry, end_of_smb,
 870                                        cifsFile->srch_inf.info_level);
 871        }
 872        kfree(tmp_buf);
 873
 874rddir2_exit:
 875        free_xid(xid);
 876        return rc;
 877}
 878