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