path: root/fs/smb/client/readdir.c

// 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"
#include "reparse.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);
	bool posix = cifs_sb_master_tcon(cifs_sb)->posix_extensions;
	bool reparse_need_reval = false;
	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
	int rc;

	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.
		 */
retry:
		if (posix) {
			switch (fattr->cf_mode & S_IFMT) {
			case S_IFLNK:
			case S_IFBLK:
			case S_IFCHR:
				reparse_need_reval = true;
				break;
			default:
				break;
			}
		} else if (fattr->cf_cifsattrs & ATTR_REPARSE) {
			reparse_need_reval = true;
		}

		if (reparse_need_reval ||
		    (fattr->cf_flags & CIFS_FATTR_NEED_REVAL))
			return;

		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) {
				/*
				 * Query dir responses don't provide enough
				 * information about reparse points other than
				 * their reparse tags.  Save an invalidation by
				 * not clobbering some existing attributes when