Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1237 insertions, 0 deletions

diff --git a/fs/smb/client/readdir.c b/fs/smb/client/readdir.c
new file mode 100644
index 000000000..2d75ba5aa
--- /dev/null
+++ b/fs/smb/client/readdir.c
@@ -0,0 +1,1237 @@
+// SPDX-License-Identifier: LGPL-2.1
+/*
+ *
+ *   Directory search handling
+ *
+ *   Copyright (C) International Business Machines  Corp., 2004, 2008
+ *   Copyright (C) Red Hat, Inc., 2011
+ *   Author(s): Steve French (sfrench@us.ibm.com)
+ *
+ */
+#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"
+#include "smb2proto.h"
+#include "fs_context.h"
+#include "cached_dir.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) {
+			cifs_dbg(FYI, "empty cifs private file data\n");
+			return;
+		}
+		if (cf->invalidHandle)
+			cifs_dbg(FYI, "Invalid handle\n");
+		if (cf->srch_inf.endOfSearch)
+			cifs_dbg(FYI, "end of search\n");
+		if (cf->srch_inf.emptyDir)
+			cifs_dbg(FYI, "empty dir\n");
+	}
+}
+#else
+static inline void dump_cifs_file_struct(struct file *file, char *label)
+{
+}
+#endif /* DEBUG2 */
+
+/*
+ * Attempt to preload the dcache with the results from the FIND_FIRST/NEXT
+ *
+ * Find the dentry that matches "name". If there isn't one, create one. If it's
+ * a negative dentry or the uniqueid or filetype(mode) changed,
+ * then drop it and recreate it.
+ */
+static void
+cifs_prime_dcache(struct dentry *parent, struct qstr *name,
+		    struct cifs_fattr *fattr)
+{
+	struct dentry *dentry, *alias;
+	struct inode *inode;
+	struct super_block *sb = parent->d_sb;
+	struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
+	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
+
+	cifs_dbg(FYI, "%s: for %s\n", __func__, name->name);
+
+	dentry = d_hash_and_lookup(parent, name);
+	if (!dentry) {
+		/*
+		 * If we know that the inode will need to be revalidated
+		 * immediately, then don't create a new dentry for it.
+		 * We'll end up doing an on the wire call either way and
+		 * this spares us an invalidation.
+		 */
+		if (fattr->cf_flags & CIFS_FATTR_NEED_REVAL)
+			return;
+retry:
+		dentry = d_alloc_parallel(parent, name, &wq);
+	}
+	if (IS_ERR(dentry))
+		return;
+	if (!d_in_lookup(dentry)) {
+		inode = d_inode(dentry);
+		if (inode) {
+			if (d_mountpoint(dentry)) {
+				dput(dentry);
+				return;
+			}
+			/*
+			 * If we're generating inode numbers, then we don't
+			 * want to clobber the existing one with the one that
+			 * the readdir code created.
+			 */
+			if (!(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM))
+				fattr->cf_uniqueid = CIFS_I(inode)->uniqueid;
+
+			/* update inode in place
+			 * if both i_ino and i_mode didn't change */
+			if (CIFS_I(inode)->uniqueid == fattr->cf_uniqueid &&
+			    cifs_fattr_to_inode(inode, fattr) == 0) {
+				dput(dentry);
+				return;
+			}
+		}
+		d_invalidate(dentry);
+		dput(dentry);
+		goto retry;
+	} else {
+		inode = cifs_iget(sb, fattr);
+		if (!inode)
+			inode = ERR_PTR(-ENOMEM);
+		alias = d_splice_alias(inode, dentry);
+		d_lookup_done(dentry);
+		if (alias && !IS_ERR(alias))
+			dput(alias);
+	}
+	dput(dentry);
+}
+
+static bool reparse_file_needs_reval(const struct cifs_fattr *fattr)
+{
+	if (!(fattr->cf_cifsattrs & ATTR_REPARSE))
+		return false;
+	/*
+	 * The DFS tags should be only intepreted by server side as per
+	 * MS-FSCC 2.1.2.1, but let's include them anyway.
+	 *
+	 * Besides, if cf_cifstag is unset (0), then we still need it to be
+	 * revalidated to know exactly what reparse point it is.
+	 */
+	switch (fattr->cf_cifstag) {
+	case IO_REPARSE_TAG_DFS:
+	case IO_REPARSE_TAG_DFSR:
+	case IO_REPARSE_TAG_SYMLINK:
+	case IO_REPARSE_TAG_NFS:
+	case 0:
+		return true;
+	}
+	return false;
+}
+
+static void
+cifs_fill_common_info(struct cifs_fattr *fattr, struct cifs_sb_info *cifs_sb)
+{
+	fattr->cf_uid = cifs_sb->ctx->linux_uid;
+	fattr->cf_gid = cifs_sb->ctx->linux_gid;
+
+	/*
+	 * The IO_REPARSE_TAG_LX_ tags originally were used by WSL but they
+	 * are preferred by the Linux client in some cases since, unlike
+	 * the NFS reparse tag (or EAs), they don't require an extra query
+	 * to determine which type of special file they represent.
+	 * TODO: go through all documented  reparse tags to see if we can
+	 * reasonably map some of them to directories vs. files vs. symlinks
+	 */
+	if (fattr->cf_cifsattrs & ATTR_DIRECTORY) {
+		fattr->cf_mode = S_IFDIR | cifs_sb->ctx->dir_mode;
+		fattr->cf_dtype = DT_DIR;
+	} else if (fattr->cf_cifstag == IO_REPARSE_TAG_LX_SYMLINK) {
+		fattr->cf_mode |= S_IFLNK | cifs_sb->ctx->file_mode;
+		fattr->cf_dtype = DT_LNK;
+	} else if (fattr->cf_cifstag == IO_REPARSE_TAG_LX_FIFO) {
+		fattr->cf_mode |= S_IFIFO | cifs_sb->ctx->file_mode;
+		fattr->cf_dtype = DT_FIFO;
+	} else if (fattr->cf_cifstag == IO_REPARSE_TAG_AF_UNIX) {
+		fattr->cf_mode |= S_IFSOCK | cifs_sb->ctx->file_mode;
+		fattr->cf_dtype = DT_SOCK;
+	} else if (fattr->cf_cifstag == IO_REPARSE_TAG_LX_CHR) {
+		fattr->cf_mode |= S_IFCHR | cifs_sb->ctx->file_mode;
+		fattr->cf_dtype = DT_CHR;
+	} else if (fattr->cf_cifstag == IO_REPARSE_TAG_LX_BLK) {
+		fattr->cf_mode |= S_IFBLK | cifs_sb->ctx->file_mode;
+		fattr->cf_dtype = DT_BLK;
+	} else { /* TODO: should we mark some other reparse points (like DFSR) as directories? */
+		fattr->cf_mode = S_IFREG | cifs_sb->ctx->file_mode;
+		fattr->cf_dtype = DT_REG;
+	}
+
+	/*
+	 * We need to revalidate it further to make a decision about whether it
+	 * is a symbolic link, DFS referral or a reparse point with a direct
+	 * access like junctions, deduplicated files, NFS symlinks.
+	 */
+	if (reparse_file_needs_reval(fattr))
+		fattr->cf_flags |= CIFS_FATTR_NEED_REVAL;
+
+	/* non-unix readdir doesn't provide nlink */
+	fattr->cf_flags |= CIFS_FATTR_UNKNOWN_NLINK;
+
+	if (fattr->cf_cifsattrs & ATTR_READONLY)
+		fattr->cf_mode &= ~S_IWUGO;
+
+	/*
+	 * We of course don't get ACL info in FIND_FIRST/NEXT results, so
+	 * mark it for revalidation so that "ls -l" will look right. It might
+	 * be super-slow, but if we don't do this then the ownership of files
+	 * may look wrong since the inodes may not have timed out by the time
+	 * "ls" does a stat() call on them.
+	 */
+	if ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_ACL) ||
+	    (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MODE_FROM_SID))
+		fattr->cf_flags |= CIFS_FATTR_NEED_REVAL;
+
+	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;
+		}
+	}
+}
+
+/* Fill a cifs_fattr struct with info from SMB_FIND_FILE_POSIX_INFO. */
+static void
+cifs_posix_to_fattr(struct cifs_fattr *fattr, struct smb2_posix_info *info,
+		    struct cifs_sb_info *cifs_sb)
+{
+	struct smb2_posix_info_parsed parsed;
+
+	posix_info_parse(info, NULL, &parsed);
+
+	memset(fattr, 0, sizeof(*fattr));
+	fattr->cf_uniqueid = le64_to_cpu(info->Inode);
+	fattr->cf_bytes = le64_to_cpu(info->AllocationSize);
+	fattr->cf_eof = le64_to_cpu(info->EndOfFile);
+
+	fattr->cf_atime = cifs_NTtimeToUnix(info->LastAccessTime);
+	fattr->cf_mtime = cifs_NTtimeToUnix(info->LastWriteTime);
+	fattr->cf_ctime = cifs_NTtimeToUnix(info->CreationTime);
+
+	fattr->cf_nlink = le32_to_cpu(info->HardLinks);
+	fattr->cf_cifsattrs = le32_to_cpu(info->DosAttributes);
+
+	/*
+	 * Since we set the inode type below we need to mask off
+	 * to avoid strange results if bits set above.
+	 * XXX: why not make server&client use the type bits?
+	 */
+	fattr->cf_mode = le32_to_cpu(info->Mode) & ~S_IFMT;
+
+	cifs_dbg(FYI, "posix fattr: dev %d, reparse %d, mode %o\n",
+		 le32_to_cpu(info->DeviceId),
+		 le32_to_cpu(info->ReparseTag),
+		 le32_to_cpu(info->Mode));
+
+	if (fattr->cf_cifsattrs & ATTR_DIRECTORY) {
+		fattr->cf_mode |= S_IFDIR;
+		fattr->cf_dtype = DT_DIR;
+	} else {
+		/*
+		 * mark anything that is not a dir as regular
+		 * file. special files should have the REPARSE
+		 * attribute and will be marked as needing revaluation
+		 */
+		fattr->cf_mode |= S_IFREG;
+		fattr->cf_dtype = DT_REG;
+	}
+
+	if (reparse_file_needs_reval(fattr))
+		fattr->cf_flags |= CIFS_FATTR_NEED_REVAL;
+
+	sid_to_id(cifs_sb, &parsed.owner, fattr, SIDOWNER);
+	sid_to_id(cifs_sb, &parsed.group, fattr, SIDGROUP);
+}
+
+static void __dir_info_to_fattr(struct cifs_fattr *fattr, const void *info)
+{
+	const FILE_DIRECTORY_INFO *fi = info;
+
+	memset(fattr, 0, sizeof(*fattr));
+	fattr->cf_cifsattrs = le32_to_cpu(fi->ExtFileAttributes);
+	fattr->cf_eof = le64_to_cpu(fi->EndOfFile);
+	fattr->cf_bytes = le64_to_cpu(fi->AllocationSize);
+	fattr->cf_createtime = le64_to_cpu(fi->CreationTime);
+	fattr->cf_atime = cifs_NTtimeToUnix(fi->LastAccessTime);
+	fattr->cf_ctime = cifs_NTtimeToUnix(fi->ChangeTime);
+	fattr->cf_mtime = cifs_NTtimeToUnix(fi->LastWriteTime);
+}
+
+void
+cifs_dir_info_to_fattr(struct cifs_fattr *fattr, FILE_DIRECTORY_INFO *info,
+		       struct cifs_sb_info *cifs_sb)
+{
+	__dir_info_to_fattr(fattr, info);
+	cifs_fill_common_info(fattr, cifs_sb);
+}
+
+static void cifs_fulldir_info_to_fattr(struct cifs_fattr *fattr,
+				       SEARCH_ID_FULL_DIR_INFO *info,
+				       struct cifs_sb_info *cifs_sb)
+{
+	__dir_info_to_fattr(fattr, info);
+
+	/* See MS-FSCC 2.4.19 FileIdFullDirectoryInformation */
+	if (fattr->cf_cifsattrs & ATTR_REPARSE)
+		fattr->cf_cifstag = le32_to_cpu(info->EaSize);
+	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_remap(cifs_sb);
+	if (!rc) {
+		tmpbuffer = kmalloc(maxpath);
+		rc = CIFSSMBQueryReparseLinkInfo(xid, ptcon, full_path,
+				tmpbuffer,
+				maxpath -1,
+				fid,
+				cifs_sb->local_nls);
+		if (CIFSSMBClose(xid, ptcon, fid)) {
+			cifs_dbg(FYI, "Error closing temporary reparsepoint open\n");
+		}
+	}
+}
+ */
+
+static int
+_initiate_cifs_search(const unsigned int xid, struct file *file,
+		     const char *full_path)
+{
+	__u16 search_flags;
+	int rc = 0;
+	struct cifsFileInfo *cifsFile;
+	struct cifs_sb_info *cifs_sb = CIFS_FILE_SB(file);
+	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;
+		}
+		spin_lock_init(&cifsFile->file_info_lock);
+		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;
+
+	cifs_dbg(FYI, "Full path: %s start at: %lld\n", 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->posix_extensions)
+		cifsFile->srch_inf.info_level = SMB_FIND_FILE_POSIX_INFO;
+	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:
+	cifs_put_tlink(tlink);
+	return rc;
+}
+
+static int
+initiate_cifs_search(const unsigned int xid, struct file *file,
+		     const char *full_path)
+{
+	int rc, retry_count = 0;
+
+	do {
+		rc = _initiate_cifs_search(xid, file, full_path);
+		/*
+		 * If we don't have enough credits to start reading the
+		 * directory just try again after short wait.
+		 */
+		if (rc != -EDEADLK)
+			break;
+
+		usleep_range(512, 2048);
+	} while (retry_count++ < 5);
+
+	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;
+	}
+	cifs_dbg(FYI, "Unicode string longer than PATH_MAX found\n");
+	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 {
+		u32 next_offset = le32_to_cpu(pDirInfo->NextEntryOffset);
+
+		if (old_entry + next_offset < old_entry) {
+			cifs_dbg(VFS, "Invalid offset %u\n", next_offset);
+			return NULL;
+		}
+		new_entry = old_entry + next_offset;
+	}
+	cifs_dbg(FYI, "new entry %p old entry %p\n", new_entry, old_entry);
+	/* validate that new_entry is not past end of SMB */
+	if (new_entry >= end_of_smb) {
+		cifs_dbg(VFS, "search entry %p began after end of SMB %p old entry %p\n",
+			 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)))  {
+		cifs_dbg(VFS, "search entry %p extends after end of SMB %p\n",
+			 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_posix(struct cifs_dirent *de,
+				   const struct smb2_posix_info *info)
+{
+	struct smb2_posix_info_parsed parsed;
+
+	/* payload should have already been checked at this point */
+	if (posix_info_parse(info, NULL, &parsed) < 0) {
+		cifs_dbg(VFS, "Invalid POSIX info payload\n");
+		return;
+	}
+
+	de->name = parsed.name;
+	de->namelen = parsed.name_len;
+	de->resume_key = info->Ignored;
+	de->ino = le64_to_cpu(info->Inode);
+}
+
+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_POSIX_INFO:
+		cifs_fill_dirent_posix(de, info);
+		break;
+	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:
+		cifs_dbg(FYI, "Unknown findfirst level %d\n", 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_inode(file);
+	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, loff_t pos,
+		struct file *file, const char *full_path,
+		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 = pos;
+	struct cifsFileInfo *cfile = file->private_data;
+	struct cifs_sb_info *cifs_sb = CIFS_FILE_SB(file);
+	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 */
+		cifs_dbg(FYI, "search backing up - close and restart search\n");
+		spin_lock(&cfile->file_info_lock);
+		if (server->ops->dir_needs_close(cfile)) {
+			cfile->invalidHandle = true;
+			spin_unlock(&cfile->file_info_lock);
+			if (server->ops->close_dir)
+				server->ops->close_dir(xid, tcon, &cfile->fid);
+		} else
+			spin_unlock(&cfile->file_info_lock);
+		if (cfile->srch_inf.ntwrk_buf_start) {
+			cifs_dbg(FYI, "freeing SMB ff cache buf on search rewind\n");
+			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, full_path);
+		if (rc) {
+			cifs_dbg(FYI, "error %d reinitiating a search on rewind\n",
+				 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) {
+		cifs_dbg(FYI, "calling findnext2\n");
+		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;
+
+		if (cfile->srch_inf.ntwrk_buf_start == NULL) {
+			cifs_dbg(VFS, "ntwrk_buf_start is NULL during readdir\n");
+			return -EIO;
+		}
+
+		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;
+		cifs_dbg(FYI, "found entry - pos_in_buf %d\n", 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 */
+			cifs_dbg(VFS, "reached end of buf searching for pos in buf %d index to find %lld rc %d\n",
+				 pos_in_buf, index_to_find, rc);
+		}
+		rc = 0;
+		*current_entry = cur_ent;
+	} else {
+		cifs_dbg(FYI, "index not in buffer - could not findnext into it\n");
+		return 0;
+	}
+
+	if (pos_in_buf >= cfile->srch_inf.entries_in_buffer) {
+		cifs_dbg(FYI, "can not return entries pos_in_buf beyond last\n");
+		*num_to_ret = 0;
+	} else
+		*num_to_ret = cfile->srch_inf.entries_in_buffer - pos_in_buf;
+
+	return rc;
+}
+
+static bool emit_cached_dirents(struct cached_dirents *cde,
+				struct dir_context *ctx)
+{
+	struct cached_dirent *dirent;
+	bool rc;
+
+	list_for_each_entry(dirent, &cde->entries, entry) {
+		/*
+		 * Skip all early entries prior to the current lseek()
+		 * position.
+		 */
+		if (ctx->pos > dirent->pos)
+			continue;
+		/*
+		 * We recorded the current ->pos value for the dirent
+		 * when we stored it in the cache.
+		 * However, this sequence of ->pos values may have holes
+		 * in it, for example dot-dirs returned from the server
+		 * are suppressed.
+		 * Handle this bu forcing ctx->pos to be the same as the
+		 * ->pos of the current dirent we emit from the cache.
+		 * This means that when we emit these entries from the cache
+		 * we now emit them with the same ->pos value as in the
+		 * initial scan.
+		 */
+		ctx->pos = dirent->pos;
+		rc = dir_emit(ctx, dirent->name, dirent->namelen,
+			      dirent->fattr.cf_uniqueid,
+			      dirent->fattr.cf_dtype);
+		if (!rc)
+			return rc;
+		ctx->pos++;
+	}
+	return true;
+}
+
+static void update_cached_dirents_count(struct cached_dirents *cde,
+					struct dir_context *ctx)
+{
+	if (cde->ctx != ctx)
+		return;
+	if (cde->is_valid || cde->is_failed)
+		return;
+
+	cde->pos++;
+}
+
+static void finished_cached_dirents_count(struct cached_dirents *cde,
+					struct dir_context *ctx)
+{
+	if (cde->ctx != ctx)
+		return;
+	if (cde->is_valid || cde->is_failed)
+		return;
+	if (ctx->pos != cde->pos)
+		return;
+
+	cde->is_valid = 1;
+}
+
+static void add_cached_dirent(struct cached_dirents *cde,
+			      struct dir_context *ctx,
+			      const char *name, int namelen,
+			      struct cifs_fattr *fattr)
+{
+	struct cached_dirent *de;
+
+	if (cde->ctx != ctx)
+		return;
+	if (cde->is_valid || cde->is_failed)
+		return;
+	if (ctx->pos != cde->pos) {
+		cde->is_failed = 1;
+		return;
+	}
+	de = kzalloc(sizeof(*de), GFP_ATOMIC);
+	if (de == NULL) {
+		cde->is_failed = 1;
+		return;
+	}
+	de->namelen = namelen;
+	de->name = kstrndup(name, namelen, GFP_ATOMIC);
+	if (de->name == NULL) {
+		kfree(de);
+		cde->is_failed = 1;
+		return;
+	}
+	de->pos = ctx->pos;
+
+	memcpy(&de->fattr, fattr, sizeof(struct cifs_fattr));
+
+	list_add_tail(&de->entry, &cde->entries);
+}
+
+static bool cifs_dir_emit(struct dir_context *ctx,
+			  const char *name, int namelen,
+			  struct cifs_fattr *fattr,
+			  struct cached_fid *cfid)
+{
+	bool rc;
+	ino_t ino = cifs_uniqueid_to_ino_t(fattr->cf_uniqueid);
+
+	rc = dir_emit(ctx, name, namelen, ino, fattr->cf_dtype);
+	if (!rc)
+		return rc;
+
+	if (cfid) {
+		mutex_lock(&cfid->dirents.de_mutex);
+		add_cached_dirent(&cfid->dirents, ctx, name, namelen,
+				  fattr);
+		mutex_unlock(&cfid->dirents.de_mutex);
+	}
+
+	return rc;
+}
+
+static int cifs_filldir(char *find_entry, struct file *file,
+			struct dir_context *ctx,
+			char *scratch_buf, unsigned int max_len,
+			struct cached_fid *cfid)
+{
+	struct cifsFileInfo *file_info = file->private_data;
+	struct super_block *sb = file_inode(file)->i_sb;
+	struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
+	struct cifs_dirent de = { NULL, };
+	struct cifs_fattr fattr;
+	struct qstr name;
+	int rc = 0;
+
+	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) {
+		cifs_dbg(VFS, "bad search response length %zd past smb end\n",
+			 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;
+		int map_type;
+
+		map_type = cifs_remap(cifs_sb);
+		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, map_type);
+		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_POSIX_INFO:
+		cifs_posix_to_fattr(&fattr,
+				    (struct smb2_posix_info *)find_entry,
+				    cifs_sb);
+		break;
+	case SMB_FIND_FILE_UNIX:
+		cifs_unix_basic_to_fattr(&fattr,
+					 &((FILE_UNIX_INFO *)find_entry)->basic,
+					 cifs_sb);
+		if (S_ISLNK(fattr.cf_mode))
+			fattr.cf_flags |= CIFS_FATTR_NEED_REVAL;
+		break;
+	case SMB_FIND_FILE_INFO_STANDARD:
+		cifs_std_info_to_fattr(&fattr,
+				       (FIND_FILE_STANDARD_INFO *)find_entry,
+				       cifs_sb);
+		break;
+	case SMB_FIND_FILE_ID_FULL_DIR_INFO:
+		cifs_fulldir_info_to_fattr(&fattr,
+					   (SEARCH_ID_FULL_DIR_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) &&
+	    couldbe_mf_symlink(&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;
+
+	cifs_prime_dcache(file_dentry(file), &name, &fattr);
+
+	return !cifs_dir_emit(ctx, name.name, name.len,
+			      &fattr, cfid);
+}
+
+
+int cifs_readdir(struct file *file, struct dir_context *ctx)
+{
+	int rc = 0;
+	unsigned int xid;
+	int i;
+	struct tcon_link *tlink = NULL;
+	struct cifs_tcon *tcon;
+	struct cifsFileInfo *cifsFile;
+	char *current_entry;
+	int num_to_fill = 0;
+	char *tmp_buf = NULL;
+	char *end_of_smb;
+	unsigned int max_len;
+	const char *full_path;
+	void *page = alloc_dentry_path();
+	struct cached_fid *cfid = NULL;
+	struct cifs_sb_info *cifs_sb = CIFS_FILE_SB(file);
+
+	xid = get_xid();
+
+	full_path = build_path_from_dentry(file_dentry(file), page);
+	if (IS_ERR(full_path)) {
+		rc = PTR_ERR(full_path);
+		goto rddir2_exit;
+	}
+
+	if (file->private_data == NULL) {
+		tlink = cifs_sb_tlink(cifs_sb);
+		if (IS_ERR(tlink))
+			goto cache_not_found;
+		tcon = tlink_tcon(tlink);
+	} else {
+		cifsFile = file->private_data;
+		tcon = tlink_tcon(cifsFile->tlink);
+	}
+
+	rc = open_cached_dir(xid, tcon, full_path, cifs_sb, false, &cfid);
+	cifs_put_tlink(tlink);
+	if (rc)
+		goto cache_not_found;
+
+	mutex_lock(&cfid->dirents.de_mutex);
+	/*
+	 * If this was reading from the start of the directory
+	 * we need to initialize scanning and storing the
+	 * directory content.
+	 */
+	if (ctx->pos == 0 && cfid->dirents.ctx == NULL) {
+		cfid->dirents.ctx = ctx;
+		cfid->dirents.pos = 2;
+	}
+	/*
+	 * If we already have the entire directory cached then
+	 * we can just serve the cache.
+	 */
+	if (cfid->dirents.is_valid) {
+		if (!dir_emit_dots(file, ctx)) {
+			mutex_unlock(&cfid->dirents.de_mutex);
+			goto rddir2_exit;
+		}
+		emit_cached_dirents(&cfid->dirents, ctx);
+		mutex_unlock(&cfid->dirents.de_mutex);
+		goto rddir2_exit;
+	}
+	mutex_unlock(&cfid->dirents.de_mutex);
+
+	/* Drop the cache while calling initiate_cifs_search and
+	 * find_cifs_entry in case there will be reconnects during
+	 * query_directory.
+	 */
+	close_cached_dir(cfid);
+	cfid = NULL;
+
+ cache_not_found:
+	/*
+	 * 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, full_path);
+		cifs_dbg(FYI, "initiate cifs search rc %d\n", rc);
+		if (rc)
+			goto rddir2_exit;
+	}
+
+	if (!dir_emit_dots(file, ctx))
+		goto rddir2_exit;
+
+	/* 1) If search is active,
+		is in current search buffer?
+		if it before then restart search
+		if after then keep searching till find it */
+	cifsFile = file->private_data;
+	if (cifsFile->srch_inf.endOfSearch) {
+		if (cifsFile->srch_inf.emptyDir) {
+			cifs_dbg(FYI, "End of search, empty dir\n");
+			rc = 0;
+			goto rddir2_exit;
+		}
+	} /* else {
+		cifsFile->invalidHandle = true;
+		tcon->ses->server->close(xid, tcon, &cifsFile->fid);
+	} */
+
+	tcon = tlink_tcon(cifsFile->tlink);
+	rc = find_cifs_entry(xid, tcon, ctx->pos, file, full_path,
+			     &current_entry, &num_to_fill);
+	open_cached_dir(xid, tcon, full_path, cifs_sb, false, &cfid);
+	if (rc) {
+		cifs_dbg(FYI, "fce error %d\n", rc);
+		goto rddir2_exit;
+	} else if (current_entry != NULL) {
+		cifs_dbg(FYI, "entry %lld found\n", ctx->pos);
+	} else {
+		if (cfid) {
+			mutex_lock(&cfid->dirents.de_mutex);
+			finished_cached_dirents_count(&cfid->dirents, ctx);
+			mutex_unlock(&cfid->dirents.de_mutex);
+		}
+		cifs_dbg(FYI, "Could not find entry\n");
+		goto rddir2_exit;
+	}
+	cifs_dbg(FYI, "loop through %d times filling dir for net buf %p\n",
+		 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;
+		goto rddir2_exit;
+	}
+
+	for (i = 0; i < num_to_fill; i++) {
+		if (current_entry == NULL) {
+			/* evaluate whether this case is an error */
+			cifs_dbg(VFS, "past SMB end,  num to fill %d i %d\n",
+				 num_to_fill, i);
+			break;
+		}
+		/*
+		 * if buggy server returns . and .. late do we want to
+		 * check for that here?
+		 */
+		*tmp_buf = 0;
+		rc = cifs_filldir(current_entry, file, ctx,
+				  tmp_buf, max_len, cfid);
+		if (rc) {
+			if (rc > 0)
+				rc = 0;
+			break;
+		}
+
+		ctx->pos++;
+		if (cfid) {
+			mutex_lock(&cfid->dirents.de_mutex);
+			update_cached_dirents_count(&cfid->dirents, ctx);
+			mutex_unlock(&cfid->dirents.de_mutex);
+		}
+
+		if (ctx->pos ==
+			cifsFile->srch_inf.index_of_last_entry) {
+			cifs_dbg(FYI, "last entry in buf at pos %lld %s\n",
+				 ctx->pos, tmp_buf);
+			cifs_save_resume_key(current_entry, cifsFile);
+			break;
+		}
+		current_entry =
+			nxt_dir_entry(current_entry, end_of_smb,
+				      cifsFile->srch_inf.info_level);
+	}
+	kfree(tmp_buf);
+
+rddir2_exit:
+	if (cfid)
+		close_cached_dir(cfid);
+	free_dentry_path(page);
+	free_xid(xid);
+	return rc;
+}