fs/cifs/cached_dir.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /*
  *  Functions to handle the cached directory entries
  *
  *  Copyright (c) 2022, Ronnie Sahlberg <lsahlber@redhat.com>
  */

 #include <linux/namei.h>
 #include "cifsglob.h"
 #include "cifsproto.h"
 #include "cifs_debug.h"
 #include "smb2proto.h"
 #include "cached_dir.h"

 static struct cached_fid *init_cached_dir(const char *path);
 static void free_cached_dir(struct cached_fid *cfid);

 static struct cached_fid *find_or_create_cached_dir(struct cached_fids *cfids,
 						    const char *path,
 						    bool lookup_only)
 {
 	struct cached_fid *cfid;

 	spin_lock(&cfids->cfid_list_lock);
 	list_for_each_entry(cfid, &cfids->entries, entry) {
 		if (!strcmp(cfid->path, path)) {
 			/*
 			 * If it doesn't have a lease it is either not yet
 			 * fully cached or it may be in the process of
 			 * being deleted due to a lease break.
 			 */
 			if (!cfid->has_lease) {
 				spin_unlock(&cfids->cfid_list_lock);
 				return NULL;
 			}
 			kref_get(&cfid->refcount);
 			spin_unlock(&cfids->cfid_list_lock);
 			return cfid;
 		}
 	}
 	if (lookup_only) {
 		spin_unlock(&cfids->cfid_list_lock);
 		return NULL;
 	}
 	if (cfids->num_entries >= MAX_CACHED_FIDS) {
 		spin_unlock(&cfids->cfid_list_lock);
 		return NULL;
 	}
 	cfid = init_cached_dir(path);
 	if (cfid == NULL) {
 		spin_unlock(&cfids->cfid_list_lock);
 		return NULL;
 	}
 	cfid->cfids = cfids;
 	cfids->num_entries++;
 	list_add(&cfid->entry, &cfids->entries);
 	cfid->on_list = true;
 	kref_get(&cfid->refcount);
 	spin_unlock(&cfids->cfid_list_lock);
 	return cfid;
 }

 static struct dentry *
 path_to_dentry(struct cifs_sb_info *cifs_sb, const char *path)
 {
 	struct dentry *dentry;
 	const char *s, *p;
 	char sep;

 	sep = CIFS_DIR_SEP(cifs_sb);
 	dentry = dget(cifs_sb->root);
 	s = path;

 	do {
 		struct inode *dir = d_inode(dentry);
 		struct dentry *child;

 		if (!S_ISDIR(dir->i_mode)) {
 			dput(dentry);
 			dentry = ERR_PTR(-ENOTDIR);
 			break;
 		}

 		/* skip separators */
 		while (*s == sep)
 			s++;
 		if (!*s)
 			break;
 		p = s++;
 		/* next separator */
 		while (*s && *s != sep)
 			s++;

 		child = lookup_positive_unlocked(p, dentry, s - p);
 		dput(dentry);
 		dentry = child;
 	} while (!IS_ERR(dentry));
 	return dentry;
 }

 /*
  * Open the and cache a directory handle.
  * If error then *cfid is not initialized.
  */
 int open_cached_dir(unsigned int xid, struct cifs_tcon *tcon,
 		    const char *path,
 		    struct cifs_sb_info *cifs_sb,
 		    bool lookup_only, struct cached_fid **ret_cfid)
 {
 	struct cifs_ses *ses;
 	struct TCP_Server_Info *server;
 	struct cifs_open_parms oparms;
 	struct smb2_create_rsp *o_rsp = NULL;
 	struct smb2_query_info_rsp *qi_rsp = NULL;
 	int resp_buftype[2];
 	struct smb_rqst rqst[2];
 	struct kvec rsp_iov[2];
 	struct kvec open_iov[SMB2_CREATE_IOV_SIZE];
 	struct kvec qi_iov[1];
 	int rc, flags = 0;
 	__le16 *utf16_path = NULL;
 	u8 oplock = SMB2_OPLOCK_LEVEL_II;
 	struct cifs_fid *pfid;
 	struct dentry *dentry = NULL;
 	struct cached_fid *cfid;
 	struct cached_fids *cfids;

 	if (tcon == NULL || tcon->cfids == NULL || tcon->nohandlecache ||
 	    is_smb1_server(tcon->ses->server))
 		return -EOPNOTSUPP;

 	ses = tcon->ses;
 	server = ses->server;
 	cfids = tcon->cfids;

 	if (!server->ops->new_lease_key)
 		return -EIO;

 	if (cifs_sb->root == NULL)
 		return -ENOENT;

 	utf16_path = cifs_convert_path_to_utf16(path, cifs_sb);
 	if (!utf16_path)
 		return -ENOMEM;

 	cfid = find_or_create_cached_dir(cfids, path, lookup_only);
 	if (cfid == NULL) {
 		kfree(utf16_path);
 		return -ENOENT;
 	}
 	/*
 	 * At this point we either have a lease already and we can just
 	 * return it. If not we are guaranteed to be the only thread accessing
 	 * this cfid.
 	 */
 	if (cfid->has_lease) {
 		*ret_cfid = cfid;
 		kfree(utf16_path);
 		return 0;
 	}

 	/*
 	 * We do not hold the lock for the open because in case
 	 * SMB2_open needs to reconnect.
 	 * This is safe because no other thread will be able to get a ref
 	 * to the cfid until we have finished opening the file and (possibly)
 	 * acquired a lease.
 	 */
 	if (smb3_encryption_required(tcon))
 		flags |= CIFS_TRANSFORM_REQ;

 	pfid = &cfid->fid;
 	server->ops->new_lease_key(pfid);

 	memset(rqst, 0, sizeof(rqst));
 	resp_buftype[0] = resp_buftype[1] = CIFS_NO_BUFFER;
 	memset(rsp_iov, 0, sizeof(rsp_iov));

 	/* Open */
 	memset(&open_iov, 0, sizeof(open_iov));
 	rqst[0].rq_iov = open_iov;
 	rqst[0].rq_nvec = SMB2_CREATE_IOV_SIZE;

 	oparms.tcon = tcon;
 	oparms.create_options = cifs_create_options(cifs_sb, CREATE_NOT_FILE);
 	oparms.desired_access = FILE_READ_ATTRIBUTES;
 	oparms.disposition = FILE_OPEN;
 	oparms.fid = pfid;
 	oparms.reconnect = false;

 	rc = SMB2_open_init(tcon, server,
 			    &rqst[0], &oplock, &oparms, utf16_path);
 	if (rc)
 		goto oshr_free;
 	smb2_set_next_command(tcon, &rqst[0]);

 	memset(&qi_iov, 0, sizeof(qi_iov));
 	rqst[1].rq_iov = qi_iov;
 	rqst[1].rq_nvec = 1;

 	rc = SMB2_query_info_init(tcon, server,
 				  &rqst[1], COMPOUND_FID,
 				  COMPOUND_FID, FILE_ALL_INFORMATION,
 				  SMB2_O_INFO_FILE, 0,
 				  sizeof(struct smb2_file_all_info) +
 				  PATH_MAX * 2, 0, NULL);
 	if (rc)
 		goto oshr_free;

 	smb2_set_related(&rqst[1]);

 	rc = compound_send_recv(xid, ses, server,
 				flags, 2, rqst,
 				resp_buftype, rsp_iov);
 	if (rc) {
 		if (rc == -EREMCHG) {
 			tcon->need_reconnect = true;
 			pr_warn_once("server share %s deleted\n",
 				     tcon->tree_name);
 		}
 		goto oshr_free;
 	}

 	atomic_inc(&tcon->num_remote_opens);

 	o_rsp = (struct smb2_create_rsp *)rsp_iov[0].iov_base;
 	oparms.fid->persistent_fid = o_rsp->PersistentFileId;
 	oparms.fid->volatile_fid = o_rsp->VolatileFileId;
 #ifdef CONFIG_CIFS_DEBUG2
 	oparms.fid->mid = le64_to_cpu(o_rsp->hdr.MessageId);
 #endif /* CIFS_DEBUG2 */

 	if (o_rsp->OplockLevel != SMB2_OPLOCK_LEVEL_LEASE)
 		goto oshr_free;


 	smb2_parse_contexts(server, o_rsp,
 			    &oparms.fid->epoch,
 			    oparms.fid->lease_key, &oplock,
 			    NULL, NULL);

 	qi_rsp = (struct smb2_query_info_rsp *)rsp_iov[1].iov_base;
 	if (le32_to_cpu(qi_rsp->OutputBufferLength) < sizeof(struct smb2_file_all_info))
 		goto oshr_free;
 	if (!smb2_validate_and_copy_iov(
 				le16_to_cpu(qi_rsp->OutputBufferOffset),
 				sizeof(struct smb2_file_all_info),
 				&rsp_iov[1], sizeof(struct smb2_file_all_info),
 				(char *)&cfid->file_all_info))
 		cfid->file_all_info_is_valid = true;

 	if (!path[0])
 		dentry = dget(cifs_sb->root);
 	else {
 		dentry = path_to_dentry(cifs_sb, path);
 		if (IS_ERR(dentry))
 			goto oshr_free;
 	}
 	cfid->dentry = dentry;
 	cfid->tcon = tcon;
 	cfid->time = jiffies;
 	cfid->is_open = true;
 	cfid->has_lease = true;

 oshr_free:
 	kfree(utf16_path);
 	SMB2_open_free(&rqst[0]);
 	SMB2_query_info_free(&rqst[1]);
 	free_rsp_buf(resp_buftype[0], rsp_iov[0].iov_base);
 	free_rsp_buf(resp_buftype[1], rsp_iov[1].iov_base);
 	spin_lock(&cfids->cfid_list_lock);
 	if (!cfid->has_lease) {
 		if (cfid->on_list) {
 			list_del(&cfid->entry);
 			cfid->on_list = false;
 			cfids->num_entries--;
 		}
 		rc = -ENOENT;
 	}
 	spin_unlock(&cfids->cfid_list_lock);
 	if (rc) {
 		free_cached_dir(cfid);
 		cfid = NULL;
 	}

 	if (rc == 0)
 		*ret_cfid = cfid;

 	return rc;
 }

 int open_cached_dir_by_dentry(struct cifs_tcon *tcon,
 			      struct dentry *dentry,
 			      struct cached_fid **ret_cfid)
 {
 	struct cached_fid *cfid;
 	struct cached_fids *cfids = tcon->cfids;

 	if (cfids == NULL)
 		return -ENOENT;

 	spin_lock(&cfids->cfid_list_lock);
 	list_for_each_entry(cfid, &cfids->entries, entry) {
 		if (dentry && cfid->dentry == dentry) {
 			cifs_dbg(FYI, "found a cached root file handle by dentry\n");
 			kref_get(&cfid->refcount);
 			*ret_cfid = cfid;
 			spin_unlock(&cfids->cfid_list_lock);
 			return 0;
 		}
 	}
 	spin_unlock(&cfids->cfid_list_lock);
 	return -ENOENT;
 }

 static void
 smb2_close_cached_fid(struct kref *ref)
 {
 	struct cached_fid *cfid = container_of(ref, struct cached_fid,
 					       refcount);

 	spin_lock(&cfid->cfids->cfid_list_lock);
 	if (cfid->on_list) {
 		list_del(&cfid->entry);
 		cfid->on_list = false;
 		cfid->cfids->num_entries--;
 	}
 	spin_unlock(&cfid->cfids->cfid_list_lock);

 	dput(cfid->dentry);
 	cfid->dentry = NULL;

 	if (cfid->is_open) {
 		SMB2_close(0, cfid->tcon, cfid->fid.persistent_fid,
 			   cfid->fid.volatile_fid);
 	}

 	free_cached_dir(cfid);
 }

 void close_cached_dir(struct cached_fid *cfid)
 {
 	kref_put(&cfid->refcount, smb2_close_cached_fid);
 }

 /*
  * Called from cifs_kill_sb when we unmount a share
  */
 void close_all_cached_dirs(struct cifs_sb_info *cifs_sb)
 {
 	struct rb_root *root = &cifs_sb->tlink_tree;
 	struct rb_node *node;
 	struct cached_fid *cfid;
 	struct cifs_tcon *tcon;
 	struct tcon_link *tlink;
 	struct cached_fids *cfids;

 	for (node = rb_first(root); node; node = rb_next(node)) {
 		tlink = rb_entry(node, struct tcon_link, tl_rbnode);
 		tcon = tlink_tcon(tlink);
 		if (IS_ERR(tcon))
 			continue;
 		cfids = tcon->cfids;
 		if (cfids == NULL)
 			continue;
 		list_for_each_entry(cfid, &cfids->entries, entry) {
 			dput(cfid->dentry);
 			cfid->dentry = NULL;
 		}
 	}
 }

 /*
  * Invalidate all cached dirs when a TCON has been reset
  * due to a session loss.
  */
 void invalidate_all_cached_dirs(struct cifs_tcon *tcon)
 {
 	struct cached_fids *cfids = tcon->cfids;
 	struct cached_fid *cfid, *q;
 	struct list_head entry;

 	INIT_LIST_HEAD(&entry);
 	spin_lock(&cfids->cfid_list_lock);
 	list_for_each_entry_safe(cfid, q, &cfids->entries, entry) {
 		list_del(&cfid->entry);
 		list_add(&cfid->entry, &entry);
 		cfids->num_entries--;
 		cfid->is_open = false;
 		/* To prevent race with smb2_cached_lease_break() */
 		kref_get(&cfid->refcount);
 	}
 	spin_unlock(&cfids->cfid_list_lock);

 	list_for_each_entry_safe(cfid, q, &entry, entry) {
 		cfid->on_list = false;
 		list_del(&cfid->entry);
 		cancel_work_sync(&cfid->lease_break);
 		if (cfid->has_lease) {
 			/*
 			 * We lease was never cancelled from the server so we
 			 * need to drop the reference.
 			 */
 			spin_lock(&cfids->cfid_list_lock);
 			cfid->has_lease = false;
 			spin_unlock(&cfids->cfid_list_lock);
 			kref_put(&cfid->refcount, smb2_close_cached_fid);
 		}
 		/* Drop the extra reference opened above*/
 		kref_put(&cfid->refcount, smb2_close_cached_fid);
 	}
 }

 static void
 smb2_cached_lease_break(struct work_struct *work)
 {
 	struct cached_fid *cfid = container_of(work,
 				struct cached_fid, lease_break);

 	spin_lock(&cfid->cfids->cfid_list_lock);
 	cfid->has_lease = false;
 	spin_unlock(&cfid->cfids->cfid_list_lock);
 	kref_put(&cfid->refcount, smb2_close_cached_fid);
 }

 int cached_dir_lease_break(struct cifs_tcon *tcon, __u8 lease_key[16])
 {
 	struct cached_fids *cfids = tcon->cfids;
 	struct cached_fid *cfid;

 	if (cfids == NULL)
 		return false;

 	spin_lock(&cfids->cfid_list_lock);
 	list_for_each_entry(cfid, &cfids->entries, entry) {
 		if (cfid->has_lease &&
 		    !memcmp(lease_key,
 			    cfid->fid.lease_key,
 			    SMB2_LEASE_KEY_SIZE)) {
 			cfid->time = 0;
 			/*
 			 * We found a lease remove it from the list
 			 * so no threads can access it.
 			 */
 			list_del(&cfid->entry);
 			cfid->on_list = false;
 			cfids->num_entries--;

 			queue_work(cifsiod_wq,
 				   &cfid->lease_break);
 			spin_unlock(&cfids->cfid_list_lock);
 			return true;
 		}
 	}
 	spin_unlock(&cfids->cfid_list_lock);
 	return false;
 }

 static struct cached_fid *init_cached_dir(const char *path)
 {
 	struct cached_fid *cfid;

 	cfid = kzalloc(sizeof(*cfid), GFP_ATOMIC);
 	if (!cfid)
 		return NULL;
 	cfid->path = kstrdup(path, GFP_ATOMIC);
 	if (!cfid->path) {
 		kfree(cfid);
 		return NULL;
 	}

 	INIT_WORK(&cfid->lease_break, smb2_cached_lease_break);
 	INIT_LIST_HEAD(&cfid->entry);
 	INIT_LIST_HEAD(&cfid->dirents.entries);
 	mutex_init(&cfid->dirents.de_mutex);
 	spin_lock_init(&cfid->fid_lock);
 	kref_init(&cfid->refcount);
 	return cfid;
 }

 static void free_cached_dir(struct cached_fid *cfid)
 {
 	struct cached_dirent *dirent, *q;

 	dput(cfid->dentry);
 	cfid->dentry = NULL;

 	/*
 	 * Delete all cached dirent names
 	 */
 	list_for_each_entry_safe(dirent, q, &cfid->dirents.entries, entry) {
 		list_del(&dirent->entry);
 		kfree(dirent->name);
 		kfree(dirent);
 	}

 	kfree(cfid->path);
 	cfid->path = NULL;
 	kfree(cfid);
 }

 struct cached_fids *init_cached_dirs(void)
 {
 	struct cached_fids *cfids;

 	cfids = kzalloc(sizeof(*cfids), GFP_KERNEL);
 	if (!cfids)
 		return NULL;
 	spin_lock_init(&cfids->cfid_list_lock);
 	INIT_LIST_HEAD(&cfids->entries);
 	return cfids;
 }

 /*
  * Called from tconInfoFree when we are tearing down the tcon.
  * There are no active users or open files/directories at this point.
  */
 void free_cached_dirs(struct cached_fids *cfids)
 {
 	struct cached_fid *cfid, *q;
 	struct list_head entry;

 	INIT_LIST_HEAD(&entry);
 	spin_lock(&cfids->cfid_list_lock);
 	list_for_each_entry_safe(cfid, q, &cfids->entries, entry) {
 		cfid->on_list = false;
 		cfid->is_open = false;
 		list_del(&cfid->entry);
 		list_add(&cfid->entry, &entry);
 	}
 	spin_unlock(&cfids->cfid_list_lock);

 	list_for_each_entry_safe(cfid, q, &entry, entry) {
 		list_del(&cfid->entry);
 		free_cached_dir(cfid);
 	}

 	kfree(cfids);
 }
	// SPDX-License-Identifier: GPL-2.0
	/*
	* Functions to handle the cached directory entries
	*
	* Copyright (c) 2022, Ronnie Sahlberg <lsahlber@redhat.com>
	*/

	#include <linux/namei.h>
	#include "cifsglob.h"
	#include "cifsproto.h"
	#include "cifs_debug.h"
	#include "smb2proto.h"
	#include "cached_dir.h"

	static struct cached_fid init_cached_dir(const char path);
	static void free_cached_dir(struct cached_fid *cfid);

	static struct cached_fid find_or_create_cached_dir(struct cached_fids cfids,
	const char *path,
	bool lookup_only)
	{
	struct cached_fid *cfid;

	spin_lock(&cfids->cfid_list_lock);
	list_for_each_entry(cfid, &cfids->entries, entry) {
	if (!strcmp(cfid->path, path)) {
	/*
	* If it doesn't have a lease it is either not yet
	* fully cached or it may be in the process of
	* being deleted due to a lease break.
	*/
	if (!cfid->has_lease) {
	spin_unlock(&cfids->cfid_list_lock);
	return NULL;
	}
	kref_get(&cfid->refcount);
	spin_unlock(&cfids->cfid_list_lock);
	return cfid;
	}
	}
	if (lookup_only) {
	spin_unlock(&cfids->cfid_list_lock);
	return NULL;
	}
	if (cfids->num_entries >= MAX_CACHED_FIDS) {
	spin_unlock(&cfids->cfid_list_lock);
	return NULL;
	}
	cfid = init_cached_dir(path);
	if (cfid == NULL) {
	spin_unlock(&cfids->cfid_list_lock);
	return NULL;
	}
	cfid->cfids = cfids;
	cfids->num_entries++;
	list_add(&cfid->entry, &cfids->entries);
	cfid->on_list = true;
	kref_get(&cfid->refcount);
	spin_unlock(&cfids->cfid_list_lock);
	return cfid;
	}

	static struct dentry *
	path_to_dentry(struct cifs_sb_info cifs_sb, const char path)
	{
	struct dentry *dentry;
	const char s, p;
	char sep;

	sep = CIFS_DIR_SEP(cifs_sb);
	dentry = dget(cifs_sb->root);
	s = path;

	do {
	struct inode *dir = d_inode(dentry);
	struct dentry *child;

	if (!S_ISDIR(dir->i_mode)) {
	dput(dentry);
	dentry = ERR_PTR(-ENOTDIR);
	break;
	}

	/* skip separators */
	while (*s == sep)
	s++;
	if (!*s)
	break;
	p = s++;
	/* next separator */
	while (s && s != sep)
	s++;

	child = lookup_positive_unlocked(p, dentry, s - p);
	dput(dentry);
	dentry = child;
	} while (!IS_ERR(dentry));
	return dentry;
	}

	/*
	* Open the and cache a directory handle.
	* If error then *cfid is not initialized.
	*/
	int open_cached_dir(unsigned int xid, struct cifs_tcon *tcon,
	const char *path,
	struct cifs_sb_info *cifs_sb,
	bool lookup_only, struct cached_fid **ret_cfid)
	{
	struct cifs_ses *ses;
	struct TCP_Server_Info *server;
	struct cifs_open_parms oparms;
	struct smb2_create_rsp *o_rsp = NULL;
	struct smb2_query_info_rsp *qi_rsp = NULL;
	int resp_buftype[2];
	struct smb_rqst rqst[2];
	struct kvec rsp_iov[2];
	struct kvec open_iov[SMB2_CREATE_IOV_SIZE];
	struct kvec qi_iov[1];
	int rc, flags = 0;
	__le16 *utf16_path = NULL;
	u8 oplock = SMB2_OPLOCK_LEVEL_II;
	struct cifs_fid *pfid;
	struct dentry *dentry = NULL;
	struct cached_fid *cfid;
	struct cached_fids *cfids;

	if (tcon == NULL \|\| tcon->cfids == NULL \|\| tcon->nohandlecache \|\|
	is_smb1_server(tcon->ses->server))
	return -EOPNOTSUPP;

	ses = tcon->ses;
	server = ses->server;
	cfids = tcon->cfids;

	if (!server->ops->new_lease_key)
	return -EIO;

	if (cifs_sb->root == NULL)
	return -ENOENT;

	utf16_path = cifs_convert_path_to_utf16(path, cifs_sb);
	if (!utf16_path)
	return -ENOMEM;

	cfid = find_or_create_cached_dir(cfids, path, lookup_only);
	if (cfid == NULL) {
	kfree(utf16_path);
	return -ENOENT;
	}
	/*
	* At this point we either have a lease already and we can just
	* return it. If not we are guaranteed to be the only thread accessing
	* this cfid.
	*/
	if (cfid->has_lease) {
	*ret_cfid = cfid;
	kfree(utf16_path);
	return 0;
	}

	/*
	* We do not hold the lock for the open because in case
	* SMB2_open needs to reconnect.
	* This is safe because no other thread will be able to get a ref
	* to the cfid until we have finished opening the file and (possibly)
	* acquired a lease.
	*/
	if (smb3_encryption_required(tcon))
	flags \|= CIFS_TRANSFORM_REQ;

	pfid = &cfid->fid;
	server->ops->new_lease_key(pfid);

	memset(rqst, 0, sizeof(rqst));
	resp_buftype[0] = resp_buftype[1] = CIFS_NO_BUFFER;
	memset(rsp_iov, 0, sizeof(rsp_iov));

	/* Open */
	memset(&open_iov, 0, sizeof(open_iov));
	rqst[0].rq_iov = open_iov;
	rqst[0].rq_nvec = SMB2_CREATE_IOV_SIZE;

	oparms.tcon = tcon;
	oparms.create_options = cifs_create_options(cifs_sb, CREATE_NOT_FILE);
	oparms.desired_access = FILE_READ_ATTRIBUTES;
	oparms.disposition = FILE_OPEN;
	oparms.fid = pfid;
	oparms.reconnect = false;

	rc = SMB2_open_init(tcon, server,
	&rqst[0], &oplock, &oparms, utf16_path);
	if (rc)
	goto oshr_free;
	smb2_set_next_command(tcon, &rqst[0]);

	memset(&qi_iov, 0, sizeof(qi_iov));
	rqst[1].rq_iov = qi_iov;
	rqst[1].rq_nvec = 1;

	rc = SMB2_query_info_init(tcon, server,
	&rqst[1], COMPOUND_FID,
	COMPOUND_FID, FILE_ALL_INFORMATION,
	SMB2_O_INFO_FILE, 0,
	sizeof(struct smb2_file_all_info) +
	PATH_MAX * 2, 0, NULL);
	if (rc)
	goto oshr_free;

	smb2_set_related(&rqst[1]);

	rc = compound_send_recv(xid, ses, server,
	flags, 2, rqst,
	resp_buftype, rsp_iov);
	if (rc) {
	if (rc == -EREMCHG) {
	tcon->need_reconnect = true;
	pr_warn_once("server share %s deleted\n",
	tcon->tree_name);
	}
	goto oshr_free;
	}

	atomic_inc(&tcon->num_remote_opens);

	o_rsp = (struct smb2_create_rsp *)rsp_iov[0].iov_base;
	oparms.fid->persistent_fid = o_rsp->PersistentFileId;
	oparms.fid->volatile_fid = o_rsp->VolatileFileId;
	#ifdef CONFIG_CIFS_DEBUG2
	oparms.fid->mid = le64_to_cpu(o_rsp->hdr.MessageId);
	#endif /* CIFS_DEBUG2 */

	if (o_rsp->OplockLevel != SMB2_OPLOCK_LEVEL_LEASE)
	goto oshr_free;


	smb2_parse_contexts(server, o_rsp,
	&oparms.fid->epoch,
	oparms.fid->lease_key, &oplock,
	NULL, NULL);

	qi_rsp = (struct smb2_query_info_rsp *)rsp_iov[1].iov_base;
	if (le32_to_cpu(qi_rsp->OutputBufferLength) < sizeof(struct smb2_file_all_info))
	goto oshr_free;
	if (!smb2_validate_and_copy_iov(
	le16_to_cpu(qi_rsp->OutputBufferOffset),
	sizeof(struct smb2_file_all_info),
	&rsp_iov[1], sizeof(struct smb2_file_all_info),
	(char *)&cfid->file_all_info))
	cfid->file_all_info_is_valid = true;

	if (!path[0])
	dentry = dget(cifs_sb->root);
	else {
	dentry = path_to_dentry(cifs_sb, path);
	if (IS_ERR(dentry))
	goto oshr_free;
	}
	cfid->dentry = dentry;
	cfid->tcon = tcon;
	cfid->time = jiffies;
	cfid->is_open = true;
	cfid->has_lease = true;

	oshr_free:
	kfree(utf16_path);
	SMB2_open_free(&rqst[0]);
	SMB2_query_info_free(&rqst[1]);
	free_rsp_buf(resp_buftype[0], rsp_iov[0].iov_base);
	free_rsp_buf(resp_buftype[1], rsp_iov[1].iov_base);
	spin_lock(&cfids->cfid_list_lock);
	if (!cfid->has_lease) {
	if (cfid->on_list) {
	list_del(&cfid->entry);
	cfid->on_list = false;
	cfids->num_entries--;
	}
	rc = -ENOENT;
	}
	spin_unlock(&cfids->cfid_list_lock);
	if (rc) {
	free_cached_dir(cfid);
	cfid = NULL;
	}

	if (rc == 0)
	*ret_cfid = cfid;

	return rc;
	}

	int open_cached_dir_by_dentry(struct cifs_tcon *tcon,
	struct dentry *dentry,
	struct cached_fid **ret_cfid)
	{
	struct cached_fid *cfid;
	struct cached_fids *cfids = tcon->cfids;

	if (cfids == NULL)
	return -ENOENT;

	spin_lock(&cfids->cfid_list_lock);
	list_for_each_entry(cfid, &cfids->entries, entry) {
	if (dentry && cfid->dentry == dentry) {
	cifs_dbg(FYI, "found a cached root file handle by dentry\n");
	kref_get(&cfid->refcount);
	*ret_cfid = cfid;
	spin_unlock(&cfids->cfid_list_lock);
	return 0;
	}
	}
	spin_unlock(&cfids->cfid_list_lock);
	return -ENOENT;
	}

	static void
	smb2_close_cached_fid(struct kref *ref)
	{
	struct cached_fid *cfid = container_of(ref, struct cached_fid,
	refcount);

	spin_lock(&cfid->cfids->cfid_list_lock);
	if (cfid->on_list) {
	list_del(&cfid->entry);
	cfid->on_list = false;
	cfid->cfids->num_entries--;
	}
	spin_unlock(&cfid->cfids->cfid_list_lock);

	dput(cfid->dentry);
	cfid->dentry = NULL;

	if (cfid->is_open) {
	SMB2_close(0, cfid->tcon, cfid->fid.persistent_fid,
	cfid->fid.volatile_fid);
	}

	free_cached_dir(cfid);
	}

	void close_cached_dir(struct cached_fid *cfid)
	{
	kref_put(&cfid->refcount, smb2_close_cached_fid);
	}

	/*
	* Called from cifs_kill_sb when we unmount a share
	*/
	void close_all_cached_dirs(struct cifs_sb_info *cifs_sb)
	{
	struct rb_root *root = &cifs_sb->tlink_tree;
	struct rb_node *node;
	struct cached_fid *cfid;
	struct cifs_tcon *tcon;
	struct tcon_link *tlink;
	struct cached_fids *cfids;

	for (node = rb_first(root); node; node = rb_next(node)) {
	tlink = rb_entry(node, struct tcon_link, tl_rbnode);
	tcon = tlink_tcon(tlink);
	if (IS_ERR(tcon))
	continue;
	cfids = tcon->cfids;
	if (cfids == NULL)
	continue;
	list_for_each_entry(cfid, &cfids->entries, entry) {
	dput(cfid->dentry);
	cfid->dentry = NULL;
	}
	}
	}

	/*
	* Invalidate all cached dirs when a TCON has been reset
	* due to a session loss.
	*/
	void invalidate_all_cached_dirs(struct cifs_tcon *tcon)
	{
	struct cached_fids *cfids = tcon->cfids;
	struct cached_fid cfid, q;
	struct list_head entry;

	INIT_LIST_HEAD(&entry);
	spin_lock(&cfids->cfid_list_lock);
	list_for_each_entry_safe(cfid, q, &cfids->entries, entry) {
	list_del(&cfid->entry);
	list_add(&cfid->entry, &entry);
	cfids->num_entries--;
	cfid->is_open = false;
	/* To prevent race with smb2_cached_lease_break() */
	kref_get(&cfid->refcount);
	}
	spin_unlock(&cfids->cfid_list_lock);

	list_for_each_entry_safe(cfid, q, &entry, entry) {
	cfid->on_list = false;
	list_del(&cfid->entry);
	cancel_work_sync(&cfid->lease_break);
	if (cfid->has_lease) {
	/*
	* We lease was never cancelled from the server so we
	* need to drop the reference.
	*/
	spin_lock(&cfids->cfid_list_lock);
	cfid->has_lease = false;
	spin_unlock(&cfids->cfid_list_lock);
	kref_put(&cfid->refcount, smb2_close_cached_fid);
	}
	/* Drop the extra reference opened above*/
	kref_put(&cfid->refcount, smb2_close_cached_fid);
	}
	}

	static void
	smb2_cached_lease_break(struct work_struct *work)
	{
	struct cached_fid *cfid = container_of(work,
	struct cached_fid, lease_break);

	spin_lock(&cfid->cfids->cfid_list_lock);
	cfid->has_lease = false;
	spin_unlock(&cfid->cfids->cfid_list_lock);
	kref_put(&cfid->refcount, smb2_close_cached_fid);
	}

	int cached_dir_lease_break(struct cifs_tcon *tcon, __u8 lease_key[16])
	{
	struct cached_fids *cfids = tcon->cfids;
	struct cached_fid *cfid;

	if (cfids == NULL)
	return false;

	spin_lock(&cfids->cfid_list_lock);
	list_for_each_entry(cfid, &cfids->entries, entry) {
	if (cfid->has_lease &&
	!memcmp(lease_key,
	cfid->fid.lease_key,
	SMB2_LEASE_KEY_SIZE)) {
	cfid->time = 0;
	/*
	* We found a lease remove it from the list
	* so no threads can access it.
	*/
	list_del(&cfid->entry);
	cfid->on_list = false;
	cfids->num_entries--;

	queue_work(cifsiod_wq,
	&cfid->lease_break);
	spin_unlock(&cfids->cfid_list_lock);
	return true;
	}
	}
	spin_unlock(&cfids->cfid_list_lock);
	return false;
	}

	static struct cached_fid init_cached_dir(const char path)
	{
	struct cached_fid *cfid;

	cfid = kzalloc(sizeof(*cfid), GFP_ATOMIC);
	if (!cfid)
	return NULL;
	cfid->path = kstrdup(path, GFP_ATOMIC);
	if (!cfid->path) {
	kfree(cfid);
	return NULL;
	}

	INIT_WORK(&cfid->lease_break, smb2_cached_lease_break);
	INIT_LIST_HEAD(&cfid->entry);
	INIT_LIST_HEAD(&cfid->dirents.entries);
	mutex_init(&cfid->dirents.de_mutex);
	spin_lock_init(&cfid->fid_lock);
	kref_init(&cfid->refcount);
	return cfid;
	}

	static void free_cached_dir(struct cached_fid *cfid)
	{
	struct cached_dirent dirent, q;

	dput(cfid->dentry);
	cfid->dentry = NULL;

	/*
	* Delete all cached dirent names
	*/
	list_for_each_entry_safe(dirent, q, &cfid->dirents.entries, entry) {
	list_del(&dirent->entry);
	kfree(dirent->name);
	kfree(dirent);
	}

	kfree(cfid->path);
	cfid->path = NULL;
	kfree(cfid);
	}

	struct cached_fids *init_cached_dirs(void)
	{
	struct cached_fids *cfids;

	cfids = kzalloc(sizeof(*cfids), GFP_KERNEL);
	if (!cfids)
	return NULL;
	spin_lock_init(&cfids->cfid_list_lock);
	INIT_LIST_HEAD(&cfids->entries);
	return cfids;
	}

	/*
	* Called from tconInfoFree when we are tearing down the tcon.
	* There are no active users or open files/directories at this point.
	*/
	void free_cached_dirs(struct cached_fids *cfids)
	{
	struct cached_fid cfid, q;
	struct list_head entry;

	INIT_LIST_HEAD(&entry);
	spin_lock(&cfids->cfid_list_lock);
	list_for_each_entry_safe(cfid, q, &cfids->entries, entry) {
	cfid->on_list = false;
	cfid->is_open = false;
	list_del(&cfid->entry);
	list_add(&cfid->entry, &entry);
	}
	spin_unlock(&cfids->cfid_list_lock);

	list_for_each_entry_safe(cfid, q, &entry, entry) {
	list_del(&cfid->entry);
	free_cached_dir(cfid);
	}

	kfree(cfids);
	}