readdir.c

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/*
 *   fs/cifs/readdir.c
 *
 *   Directory search handling
 *
 *   Copyright (C) International Business Machines  Corp., 2004, 2008
 *   Copyright (C) Red Hat, Inc., 2011
 *   Author(s): Steve French ([email protected])
 *
 *   This library is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU Lesser General Public License as published
 *   by the Free Software Foundation; either version 2.1 of the License, or
 *   (at your option) any later version.
 *
 *   This library is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
 *   the GNU Lesser General Public License for more details.
 *
 *   You should have received a copy of the GNU Lesser General Public License
 *   along with this library; if not, write to the Free Software
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */
#include <linux/fs.h>
#include <linux/pagemap.h>
#include <linux/slab.h>
#include <linux/stat.h>
#include "cifspdu.h"
#include "cifsglob.h"
#include "cifsproto.h"
#include "cifs_unicode.h"
#include "cifs_debug.h"
#include "cifs_fs_sb.h"
#include "cifsfs.h"

/*
 * To be safe - for UCS to UTF-8 with strings loaded with the rare long
 * characters alloc more to account for such multibyte target UTF-8
 * characters.
 */
#define UNICODE_NAME_MAX ((4 * NAME_MAX) + 2)

#ifdef CONFIG_CIFS_DEBUG2
static void dump_cifs_file_struct(struct file *file, char *label)
{
    struct cifsFileInfo *cf;

    if (file) {
        cf = file->private_data;
        if (cf == NULL) {
            cFYI(1, "empty cifs private file data");
            return;
        }
        if (cf->invalidHandle)
            cFYI(1, "invalid handle");
        if (cf->srch_inf.endOfSearch)
            cFYI(1, "end of search");
        if (cf->srch_inf.emptyDir)
            cFYI(1, "empty dir");
    }
}
#else
static inline void dump_cifs_file_struct(struct file *file, char *label)
{
}
#endif /* DEBUG2 */

/*
 * Find the dentry that matches "name". If there isn't one, create one. If it's
 * a negative dentry or the uniqueid changed, then drop it and recreate it.
 */
static struct dentry *
cifs_readdir_lookup(struct dentry *parent, struct qstr *name,
            struct cifs_fattr *fattr)
{
    struct dentry *dentry, *alias;
    struct inode *inode;
    struct super_block *sb = parent->d_inode->i_sb;

    cFYI(1, "For %s", name->name);

    if (parent->d_op && parent->d_op->d_hash)
        parent->d_op->d_hash(parent, parent->d_inode, name);
    else
        name->hash = full_name_hash(name->name, name->len);

    dentry = d_lookup(parent, name);
    if (dentry) {
        int err;
        inode = dentry->d_inode;
        /* update inode in place if i_ino didn't change */
        if (inode && CIFS_I(inode)->uniqueid == fattr->cf_uniqueid) {
            cifs_fattr_to_inode(inode, fattr);
            return dentry;
        }
        err = d_invalidate(dentry);
        dput(dentry);
        if (err)
            return NULL;
    }

    dentry = d_alloc(parent, name);
    if (dentry == NULL)
        return NULL;

    inode = cifs_iget(sb, fattr);
    if (!inode) {
        dput(dentry);
        return NULL;
    }

    alias = d_materialise_unique(dentry, inode);
    if (alias != NULL) {
        dput(dentry);
        if (IS_ERR(alias))
            return NULL;
        dentry = alias;
    }

    return dentry;
}

static void
cifs_fill_common_info(struct cifs_fattr *fattr, struct cifs_sb_info *cifs_sb)
{
    fattr->cf_uid = cifs_sb->mnt_uid;
    fattr->cf_gid = cifs_sb->mnt_gid;

    if (fattr->cf_cifsattrs & ATTR_DIRECTORY) {
        fattr->cf_mode = S_IFDIR | cifs_sb->mnt_dir_mode;
        fattr->cf_dtype = DT_DIR;
    } else {
        fattr->cf_mode = S_IFREG | cifs_sb->mnt_file_mode;
        fattr->cf_dtype = DT_REG;
    }

    if (fattr->cf_cifsattrs & ATTR_READONLY)
        fattr->cf_mode &= ~S_IWUGO;

    if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_UNX_EMUL &&
        fattr->cf_cifsattrs & ATTR_SYSTEM) {
        if (fattr->cf_eof == 0)  {
            fattr->cf_mode &= ~S_IFMT;
            fattr->cf_mode |= S_IFIFO;
            fattr->cf_dtype = DT_FIFO;
        } else {
            /*
             * trying to get the type and mode via SFU can be slow,
             * so just call those regular files for now, and mark
             * for reval
             */
            fattr->cf_flags |= CIFS_FATTR_NEED_REVAL;
        }
    }
}

void
cifs_dir_info_to_fattr(struct cifs_fattr *fattr, FILE_DIRECTORY_INFO *info,
               struct cifs_sb_info *cifs_sb)
{
    memset(fattr, 0, sizeof(*fattr));
    fattr->cf_cifsattrs = le32_to_cpu(info->ExtFileAttributes);
    fattr->cf_eof = le64_to_cpu(info->EndOfFile);
    fattr->cf_bytes = le64_to_cpu(info->AllocationSize);
    fattr->cf_createtime = le64_to_cpu(info->CreationTime);
    fattr->cf_atime = cifs_NTtimeToUnix(info->LastAccessTime);
    fattr->cf_ctime = cifs_NTtimeToUnix(info->ChangeTime);
    fattr->cf_mtime = cifs_NTtimeToUnix(info->LastWriteTime);

    cifs_fill_common_info(fattr, cifs_sb);
}

static void
cifs_std_info_to_fattr(struct cifs_fattr *fattr, FIND_FILE_STANDARD_INFO *info,
               struct cifs_sb_info *cifs_sb)
{
    int offset = cifs_sb_master_tcon(cifs_sb)->ses->server->timeAdj;

    memset(fattr, 0, sizeof(*fattr));
    fattr->cf_atime = cnvrtDosUnixTm(info->LastAccessDate,
                        info->LastAccessTime, offset);
    fattr->cf_ctime = cnvrtDosUnixTm(info->LastWriteDate,
                        info->LastWriteTime, offset);
    fattr->cf_mtime = cnvrtDosUnixTm(info->LastWriteDate,
                        info->LastWriteTime, offset);

    fattr->cf_cifsattrs = le16_to_cpu(info->Attributes);
    fattr->cf_bytes = le32_to_cpu(info->AllocationSize);
    fattr->cf_eof = le32_to_cpu(info->DataSize);

    cifs_fill_common_info(fattr, cifs_sb);
}

/* BB eventually need to add the following helper function to
      resolve NT_STATUS_STOPPED_ON_SYMLINK return code when
      we try to do FindFirst on (NTFS) directory symlinks */
/*
int get_symlink_reparse_path(char *full_path, struct cifs_sb_info *cifs_sb,
                 unsigned int xid)
{
    __u16 fid;
    int len;
    int oplock = 0;
    int rc;
    struct cifs_tcon *ptcon = cifs_sb_tcon(cifs_sb);
    char *tmpbuffer;

    rc = CIFSSMBOpen(xid, ptcon, full_path, FILE_OPEN, GENERIC_READ,
            OPEN_REPARSE_POINT, &fid, &oplock, NULL,
            cifs_sb->local_nls,
            cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR);
    if (!rc) {
        tmpbuffer = kmalloc(maxpath);
        rc = CIFSSMBQueryReparseLinkInfo(xid, ptcon, full_path,
                tmpbuffer,
                maxpath -1,
                fid,
                cifs_sb->local_nls);
        if (CIFSSMBClose(xid, ptcon, fid)) {
            cFYI(1, "Error closing temporary reparsepoint open");
        }
    }
}
 */

static int
initiate_cifs_search(const unsigned int xid, struct file *file)
{
    __u16 search_flags;
    int rc = 0;
    char *full_path = NULL;
    struct cifsFileInfo *cifsFile;
    struct cifs_sb_info *cifs_sb = CIFS_SB(file->f_path.dentry->d_sb);
    struct tcon_link *tlink = NULL;
    struct cifs_tcon *tcon;
    struct TCP_Server_Info *server;

    if (file->private_data == NULL) {
        tlink = cifs_sb_tlink(cifs_sb);
        if (IS_ERR(tlink))
            return PTR_ERR(tlink);

        cifsFile = kzalloc(sizeof(struct cifsFileInfo), GFP_KERNEL);
        if (cifsFile == NULL) {
            rc = -ENOMEM;
            goto error_exit;
        }
        file->private_data = cifsFile;
        cifsFile->tlink = cifs_get_tlink(tlink);
        tcon = tlink_tcon(tlink);
    } else {
        cifsFile = file->private_data;
        tcon = tlink_tcon(cifsFile->tlink);
    }

    server = tcon->ses->server;

    if (!server->ops->query_dir_first) {
        rc = -ENOSYS;
        goto error_exit;
    }

    cifsFile->invalidHandle = true;
    cifsFile->srch_inf.endOfSearch = false;

    full_path = build_path_from_dentry(file->f_path.dentry);
    if (full_path == NULL) {
        rc = -ENOMEM;
        goto error_exit;
    }

    cFYI(1, "Full path: %s start at: %lld", full_path, file->f_pos);

ffirst_retry:
    /* test for Unix extensions */
    /* but now check for them on the share/mount not on the SMB session */
    /* if (cap_unix(tcon->ses) { */
    if (tcon->unix_ext)
        cifsFile->srch_inf.info_level = SMB_FIND_FILE_UNIX;
    else if ((tcon->ses->capabilities &
          tcon->ses->server->vals->cap_nt_find) == 0) {
        cifsFile->srch_inf.info_level = SMB_FIND_FILE_INFO_STANDARD;
    } else if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM) {
        cifsFile->srch_inf.info_level = SMB_FIND_FILE_ID_FULL_DIR_INFO;
    } else /* not srvinos - BB fixme add check for backlevel? */ {
        cifsFile->srch_inf.info_level = SMB_FIND_FILE_DIRECTORY_INFO;
    }

    search_flags = CIFS_SEARCH_CLOSE_AT_END | CIFS_SEARCH_RETURN_RESUME;
    if (backup_cred(cifs_sb))
        search_flags |= CIFS_SEARCH_BACKUP_SEARCH;

    rc = server->ops->query_dir_first(xid, tcon, full_path, cifs_sb,
                      &cifsFile->fid, search_flags,
                      &cifsFile->srch_inf);

    if (rc == 0)
        cifsFile->invalidHandle = false;
    /* BB add following call to handle readdir on new NTFS symlink errors
    else if STATUS_STOPPED_ON_SYMLINK
        call get_symlink_reparse_path and retry with new path */
    else if ((rc == -EOPNOTSUPP) &&
        (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM)) {
        cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_SERVER_INUM;
        goto ffirst_retry;
    }
error_exit:
    kfree(full_path);
    cifs_put_tlink(tlink);
    return rc;
}

/* return length of unicode string in bytes */
static int cifs_unicode_bytelen(const char *str)
{
    int len;
    const __le16 *ustr = (const __le16 *)str;

    for (len = 0; len <= PATH_MAX; len++) {
        if (ustr[len] == 0)
            return len << 1;
    }
    cFYI(1, "Unicode string longer than PATH_MAX found");
    return len << 1;
}

static char *nxt_dir_entry(char *old_entry, char *end_of_smb, int level)
{
    char *new_entry;
    FILE_DIRECTORY_INFO *pDirInfo = (FILE_DIRECTORY_INFO *)old_entry;

    if (level == SMB_FIND_FILE_INFO_STANDARD) {
        FIND_FILE_STANDARD_INFO *pfData;
        pfData = (FIND_FILE_STANDARD_INFO *)pDirInfo;

        new_entry = old_entry + sizeof(FIND_FILE_STANDARD_INFO) +
                pfData->FileNameLength;
    } else
        new_entry = old_entry + le32_to_cpu(pDirInfo->NextEntryOffset);
    cFYI(1, "new entry %p old entry %p", new_entry, old_entry);
    /* validate that new_entry is not past end of SMB */
    if (new_entry >= end_of_smb) {
        cERROR(1, "search entry %p began after end of SMB %p old entry %p",
            new_entry, end_of_smb, old_entry);
        return NULL;
    } else if (((level == SMB_FIND_FILE_INFO_STANDARD) &&
            (new_entry + sizeof(FIND_FILE_STANDARD_INFO) > end_of_smb))
          || ((level != SMB_FIND_FILE_INFO_STANDARD) &&
           (new_entry + sizeof(FILE_DIRECTORY_INFO) > end_of_smb)))  {
        cERROR(1, "search entry %p extends after end of SMB %p",
            new_entry, end_of_smb);
        return NULL;
    } else
        return new_entry;

}

struct cifs_dirent {
    const char  *name;
    size_t      namelen;
    u32     resume_key;
    u64     ino;
};

static void cifs_fill_dirent_unix(struct cifs_dirent *de,
        const FILE_UNIX_INFO *info, bool is_unicode)
{
    de->name = &info->FileName[0];
    if (is_unicode)
        de->namelen = cifs_unicode_bytelen(de->name);
    else
        de->namelen = strnlen(de->name, PATH_MAX);
    de->resume_key = info->ResumeKey;
    de->ino = le64_to_cpu(info->basic.UniqueId);
}

static void cifs_fill_dirent_dir(struct cifs_dirent *de,
        const FILE_DIRECTORY_INFO *info)
{
    de->name = &info->FileName[0];
    de->namelen = le32_to_cpu(info->FileNameLength);
    de->resume_key = info->FileIndex;
}

static void cifs_fill_dirent_full(struct cifs_dirent *de,
        const FILE_FULL_DIRECTORY_INFO *info)
{
    de->name = &info->FileName[0];
    de->namelen = le32_to_cpu(info->FileNameLength);
    de->resume_key = info->FileIndex;
}

static void cifs_fill_dirent_search(struct cifs_dirent *de,
        const SEARCH_ID_FULL_DIR_INFO *info)
{
    de->name = &info->FileName[0];
    de->namelen = le32_to_cpu(info->FileNameLength);
    de->resume_key = info->FileIndex;
    de->ino = le64_to_cpu(info->UniqueId);
}

static void cifs_fill_dirent_both(struct cifs_dirent *de,
        const FILE_BOTH_DIRECTORY_INFO *info)
{
    de->name = &info->FileName[0];
    de->namelen = le32_to_cpu(info->FileNameLength);
    de->resume_key = info->FileIndex;
}

static void cifs_fill_dirent_std(struct cifs_dirent *de,
        const FIND_FILE_STANDARD_INFO *info)
{
    de->name = &info->FileName[0];
    /* one byte length, no endianess conversion */
    de->namelen = info->FileNameLength;
    de->resume_key = info->ResumeKey;
}

static int cifs_fill_dirent(struct cifs_dirent *de, const void *info,
        u16 level, bool is_unicode)
{
    memset(de, 0, sizeof(*de));

    switch (level) {
    case SMB_FIND_FILE_UNIX:
        cifs_fill_dirent_unix(de, info, is_unicode);
        break;
    case SMB_FIND_FILE_DIRECTORY_INFO:
        cifs_fill_dirent_dir(de, info);
        break;
    case SMB_FIND_FILE_FULL_DIRECTORY_INFO:
        cifs_fill_dirent_full(de, info);
        break;
    case SMB_FIND_FILE_ID_FULL_DIR_INFO:
        cifs_fill_dirent_search(de, info);
        break;
    case SMB_FIND_FILE_BOTH_DIRECTORY_INFO:
        cifs_fill_dirent_both(de, info);
        break;
    case SMB_FIND_FILE_INFO_STANDARD:
        cifs_fill_dirent_std(de, info);
        break;
    default:
        cFYI(1, "Unknown findfirst level %d", level);
        return -EINVAL;
    }

    return 0;
}

#define UNICODE_DOT cpu_to_le16(0x2e)

/* return 0 if no match and 1 for . (current directory) and 2 for .. (parent) */
static int cifs_entry_is_dot(struct cifs_dirent *de, bool is_unicode)
{
    int rc = 0;

    if (!de->name)
        return 0;

    if (is_unicode) {
        __le16 *ufilename = (__le16 *)de->name;
        if (de->namelen == 2) {
            /* check for . */
            if (ufilename[0] == UNICODE_DOT)
                rc = 1;
        } else if (de->namelen == 4) {
            /* check for .. */
            if (ufilename[0] == UNICODE_DOT &&
                ufilename[1] == UNICODE_DOT)
                rc = 2;
        }
    } else /* ASCII */ {
        if (de->namelen == 1) {
            if (de->name[0] == '.')
                rc = 1;
        } else if (de->namelen == 2) {
            if (de->name[0] == '.' && de->name[1] == '.')
                rc = 2;
        }
    }

    return rc;
}

/* Check if directory that we are searching has changed so we can decide
   whether we can use the cached search results from the previous search */
static int is_dir_changed(struct file *file)
{
    struct inode *inode = file->f_path.dentry->d_inode;
    struct cifsInodeInfo *cifsInfo = CIFS_I(inode);

    if (cifsInfo->time == 0)
        return 1; /* directory was changed, perhaps due to unlink */
    else
        return 0;

}

static int cifs_save_resume_key(const char *current_entry,
    struct cifsFileInfo *file_info)
{
    struct cifs_dirent de;
    int rc;

    rc = cifs_fill_dirent(&de, current_entry, file_info->srch_inf.info_level,
                  file_info->srch_inf.unicode);
    if (!rc) {
        file_info->srch_inf.presume_name = de.name;
        file_info->srch_inf.resume_name_len = de.namelen;
        file_info->srch_inf.resume_key = de.resume_key;
    }
    return rc;
}

/*
 * Find the corresponding entry in the search. Note that the SMB server returns
 * search entries for . and .. which complicates logic here if we choose to
 * parse for them and we do not assume that they are located in the findfirst
 * return buffer. We start counting in the buffer with entry 2 and increment for
 * every entry (do not increment for . or .. entry).
 */
static int
find_cifs_entry(const unsigned int xid, struct cifs_tcon *tcon,
        struct file *file, char **current_entry, int *num_to_ret)
{
    __u16 search_flags;
    int rc = 0;
    int pos_in_buf = 0;
    loff_t first_entry_in_buffer;
    loff_t index_to_find = file->f_pos;
    struct cifsFileInfo *cfile = file->private_data;
    struct cifs_sb_info *cifs_sb = CIFS_SB(file->f_path.dentry->d_sb);
    struct TCP_Server_Info *server = tcon->ses->server;
    /* check if index in the buffer */

    if (!server->ops->query_dir_first || !server->ops->query_dir_next)
        return -ENOSYS;

    if ((cfile == NULL) || (current_entry == NULL) || (num_to_ret == NULL))
        return -ENOENT;

    *current_entry = NULL;
    first_entry_in_buffer = cfile->srch_inf.index_of_last_entry -
                    cfile->srch_inf.entries_in_buffer;

    /*
     * If first entry in buf is zero then is first buffer
     * in search response data which means it is likely . and ..
     * will be in this buffer, although some servers do not return
     * . and .. for the root of a drive and for those we need
     * to start two entries earlier.
     */

    dump_cifs_file_struct(file, "In fce ");
    if (((index_to_find < cfile->srch_inf.index_of_last_entry) &&
         is_dir_changed(file)) || (index_to_find < first_entry_in_buffer)) {
        /* close and restart search */
        cFYI(1, "search backing up - close and restart search");
        spin_lock(&cifs_file_list_lock);
        if (!cfile->srch_inf.endOfSearch && !cfile->invalidHandle) {
            cfile->invalidHandle = true;
            spin_unlock(&cifs_file_list_lock);
            if (server->ops->close)
                server->ops->close(xid, tcon, &cfile->fid);
        } else
            spin_unlock(&cifs_file_list_lock);
        if (cfile->srch_inf.ntwrk_buf_start) {
            cFYI(1, "freeing SMB ff cache buf on search rewind");
            if (cfile->srch_inf.smallBuf)
                cifs_small_buf_release(cfile->srch_inf.
                        ntwrk_buf_start);
            else
                cifs_buf_release(cfile->srch_inf.
                        ntwrk_buf_start);
            cfile->srch_inf.ntwrk_buf_start = NULL;
        }
        rc = initiate_cifs_search(xid, file);
        if (rc) {
            cFYI(1, "error %d reinitiating a search on rewind",
                 rc);
            return rc;
        }
        /* FindFirst/Next set last_entry to NULL on malformed reply */
        if (cfile->srch_inf.last_entry)
            cifs_save_resume_key(cfile->srch_inf.last_entry, cfile);
    }

    search_flags = CIFS_SEARCH_CLOSE_AT_END | CIFS_SEARCH_RETURN_RESUME;
    if (backup_cred(cifs_sb))
        search_flags |= CIFS_SEARCH_BACKUP_SEARCH;

    while ((index_to_find >= cfile->srch_inf.index_of_last_entry) &&
           (rc == 0) && !cfile->srch_inf.endOfSearch) {
        cFYI(1, "calling findnext2");
        rc = server->ops->query_dir_next(xid, tcon, &cfile->fid,
                         search_flags,
                         &cfile->srch_inf);
        /* FindFirst/Next set last_entry to NULL on malformed reply */
        if (cfile->srch_inf.last_entry)
            cifs_save_resume_key(cfile->srch_inf.last_entry, cfile);
        if (rc)
            return -ENOENT;
    }
    if (index_to_find < cfile->srch_inf.index_of_last_entry) {
        /* we found the buffer that contains the entry */
        /* scan and find it */
        int i;
        char *cur_ent;
        char *end_of_smb = cfile->srch_inf.ntwrk_buf_start +
            server->ops->calc_smb_size(
                    cfile->srch_inf.ntwrk_buf_start);

        cur_ent = cfile->srch_inf.srch_entries_start;
        first_entry_in_buffer = cfile->srch_inf.index_of_last_entry
                    - cfile->srch_inf.entries_in_buffer;
        pos_in_buf = index_to_find - first_entry_in_buffer;
        cFYI(1, "found entry - pos_in_buf %d", pos_in_buf);

        for (i = 0; (i < (pos_in_buf)) && (cur_ent != NULL); i++) {
            /* go entry by entry figuring out which is first */
            cur_ent = nxt_dir_entry(cur_ent, end_of_smb,
                        cfile->srch_inf.info_level);
        }
        if ((cur_ent == NULL) && (i < pos_in_buf)) {
            /* BB fixme - check if we should flag this error */
            cERROR(1, "reached end of buf searching for pos in buf"
                  " %d index to find %lld rc %d", pos_in_buf,
                  index_to_find, rc);
        }
        rc = 0;
        *current_entry = cur_ent;
    } else {
        cFYI(1, "index not in buffer - could not findnext into it");
        return 0;
    }

    if (pos_in_buf >= cfile->srch_inf.entries_in_buffer) {
        cFYI(1, "can not return entries pos_in_buf beyond last");
        *num_to_ret = 0;
    } else
        *num_to_ret = cfile->srch_inf.entries_in_buffer - pos_in_buf;

    return rc;
}

static int cifs_filldir(char *find_entry, struct file *file, filldir_t filldir,
        void *dirent, char *scratch_buf, unsigned int max_len)
{
    struct cifsFileInfo *file_info = file->private_data;
    struct super_block *sb = file->f_path.dentry->d_sb;
    struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
    struct cifs_dirent de = { NULL, };
    struct cifs_fattr fattr;
    struct dentry *dentry;
    struct qstr name;
    int rc = 0;
    ino_t ino;

    rc = cifs_fill_dirent(&de, find_entry, file_info->srch_inf.info_level,
                  file_info->srch_inf.unicode);
    if (rc)
        return rc;

    if (de.namelen > max_len) {
        cERROR(1, "bad search response length %zd past smb end",
              de.namelen);
        return -EINVAL;
    }

    /* skip . and .. since we added them first */
    if (cifs_entry_is_dot(&de, file_info->srch_inf.unicode))
        return 0;

    if (file_info->srch_inf.unicode) {
        struct nls_table *nlt = cifs_sb->local_nls;

        name.name = scratch_buf;
        name.len =
            cifs_from_utf16((char *)name.name, (__le16 *)de.name,
                    UNICODE_NAME_MAX,
                    min_t(size_t, de.namelen,
                          (size_t)max_len), nlt,
                    cifs_sb->mnt_cifs_flags &
                        CIFS_MOUNT_MAP_SPECIAL_CHR);
        name.len -= nls_nullsize(nlt);
    } else {
        name.name = de.name;
        name.len = de.namelen;
    }

    switch (file_info->srch_inf.info_level) {
    case SMB_FIND_FILE_UNIX:
        cifs_unix_basic_to_fattr(&fattr,
                     &((FILE_UNIX_INFO *)find_entry)->basic,
                     cifs_sb);
        break;
    case SMB_FIND_FILE_INFO_STANDARD:
        cifs_std_info_to_fattr(&fattr,
                       (FIND_FILE_STANDARD_INFO *)find_entry,
                       cifs_sb);
        break;
    default:
        cifs_dir_info_to_fattr(&fattr,
                       (FILE_DIRECTORY_INFO *)find_entry,
                       cifs_sb);
        break;
    }

    if (de.ino && (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM)) {
        fattr.cf_uniqueid = de.ino;
    } else {
        fattr.cf_uniqueid = iunique(sb, ROOT_I);
        cifs_autodisable_serverino(cifs_sb);
    }

    if ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS) &&
        CIFSCouldBeMFSymlink(&fattr))
        /*
         * trying to get the type and mode can be slow,
         * so just call those regular files for now, and mark
         * for reval
         */
        fattr.cf_flags |= CIFS_FATTR_NEED_REVAL;

    ino = cifs_uniqueid_to_ino_t(fattr.cf_uniqueid);
    dentry = cifs_readdir_lookup(file->f_dentry, &name, &fattr);

    rc = filldir(dirent, name.name, name.len, file->f_pos, ino,
             fattr.cf_dtype);

    dput(dentry);
    return rc;
}


int cifs_readdir(struct file *file, void *direntry, filldir_t filldir)
{
    int rc = 0;
    unsigned int xid;
    int i;
    struct cifs_tcon *tcon;
    struct cifsFileInfo *cifsFile = NULL;
    char *current_entry;
    int num_to_fill = 0;
    char *tmp_buf = NULL;
    char *end_of_smb;
    unsigned int max_len;

    xid = get_xid();

    /*
     * Ensure FindFirst doesn't fail before doing filldir() for '.' and
     * '..'. Otherwise we won't be able to notify VFS in case of failure.
     */
    if (file->private_data == NULL) {
        rc = initiate_cifs_search(xid, file);
        cFYI(1, "initiate cifs search rc %d", rc);
        if (rc)
            goto rddir2_exit;
    }

    switch ((int) file->f_pos) {
    case 0:
        if (filldir(direntry, ".", 1, file->f_pos,
             file->f_path.dentry->d_inode->i_ino, DT_DIR) < 0) {
            cERROR(1, "Filldir for current dir failed");
            rc = -ENOMEM;
            break;
        }
        file->f_pos++;
    case 1:
        if (filldir(direntry, "..", 2, file->f_pos,
             parent_ino(file->f_path.dentry), DT_DIR) < 0) {
            cERROR(1, "Filldir for parent dir failed");
            rc = -ENOMEM;
            break;
        }
        file->f_pos++;
    default:
        /* 1) If search is active,
            is in current search buffer?
            if it before then restart search
            if after then keep searching till find it */

        if (file->private_data == NULL) {
            rc = -EINVAL;
            free_xid(xid);
            return rc;
        }
        cifsFile = file->private_data;
        if (cifsFile->srch_inf.endOfSearch) {
            if (cifsFile->srch_inf.emptyDir) {
                cFYI(1, "End of search, empty dir");
                rc = 0;
                break;
            }
        } /* else {
            cifsFile->invalidHandle = true;
            tcon->ses->server->close(xid, tcon, &cifsFile->fid);
        } */

        tcon = tlink_tcon(cifsFile->tlink);
        rc = find_cifs_entry(xid, tcon, file, &current_entry,
                     &num_to_fill);
        if (rc) {
            cFYI(1, "fce error %d", rc);
            goto rddir2_exit;
        } else if (current_entry != NULL) {
            cFYI(1, "entry %lld found", file->f_pos);
        } else {
            cFYI(1, "could not find entry");
            goto rddir2_exit;
        }
        cFYI(1, "loop through %d times filling dir for net buf %p",
            num_to_fill, cifsFile->srch_inf.ntwrk_buf_start);
        max_len = tcon->ses->server->ops->calc_smb_size(
                cifsFile->srch_inf.ntwrk_buf_start);
        end_of_smb = cifsFile->srch_inf.ntwrk_buf_start + max_len;

        tmp_buf = kmalloc(UNICODE_NAME_MAX, GFP_KERNEL);
        if (tmp_buf == NULL) {
            rc = -ENOMEM;
            break;
        }

        for (i = 0; (i < num_to_fill) && (rc == 0); i++) {
            if (current_entry == NULL) {
                /* evaluate whether this case is an error */
                cERROR(1, "past SMB end,  num to fill %d i %d",
                      num_to_fill, i);
                break;
            }
            /*
             * if buggy server returns . and .. late do we want to
             * check for that here?
             */
            rc = cifs_filldir(current_entry, file, filldir,
                      direntry, tmp_buf, max_len);
            if (rc == -EOVERFLOW) {
                rc = 0;
                break;
            }

            file->f_pos++;
            if (file->f_pos ==
                cifsFile->srch_inf.index_of_last_entry) {
                cFYI(1, "last entry in buf at pos %lld %s",
                    file->f_pos, tmp_buf);
                cifs_save_resume_key(current_entry, cifsFile);
                break;
            } else
                current_entry =
                    nxt_dir_entry(current_entry, end_of_smb,
                        cifsFile->srch_inf.info_level);
        }
        kfree(tmp_buf);
        break;
    } /* end switch */

rddir2_exit:
    free_xid(xid);
    return rc;
}