[linux-block.git] / fs / cifs / cached_dir.c

// 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 void smb2_close_cached_fid(struct kref *ref);

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;
}

static const char *path_no_prefix(struct cifs_sb_info *cifs_sb,
				  const char *path)
{
	size_t len = 0;

	if (!*path)
		return path;

	if ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_USE_PREFIX_PATH) &&
	    cifs_sb->prepath) {
		len = strlen(cifs_sb->prepath) + 1;
		if (unlikely(len > strlen(path)))
			return ERR_PTR(-EINVAL);
	}
	return path + len;
}

/*
 * 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;
	const char *npath;

	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;
	}

	/*
	 * Skip any prefix paths in @path as lookup_positive_unlocked() ends up
	 * calling ->lookup() which already adds those through
	 * build_path_from_dentry().  Also, do it earlier as we might reconnect
	 * below when trying to send compounded request and then potentially
	 * having a different prefix path (e.g. after DFS failover).
	 */
	npath = path_no_prefix(cifs_sb, path);
	if (IS_ERR(npath)) {
		rc = PTR_ERR(npath);
		kfree(utf16_path);
		return rc;
	}

	/*
	 * 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 = (struct cifs_open_parms) {
		.tcon = tcon,
		.path = path,
		.create_options = cifs_create_options(cifs_sb, CREATE_NOT_FILE),
		.desired_access = FILE_READ_ATTRIBUTES,
		.disposition = FILE_OPEN,
		.fid = pfid,
	};

	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;
	}
	cfid->tcon = tcon;
	cfid->is_open = true;

	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);
	if (!(oplock & SMB2_LEASE_READ_CACHING_HE))
		goto oshr_free;
	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 (!npath[0])
		dentry = dget(cifs_sb->root);
	else {
		dentry = path_to_dentry(cifs_sb, npath);
		if (IS_ERR(dentry)) {
			rc = -ENOENT;
			goto oshr_free;
		}
	}
	cfid->dentry = dentry;
	cfid->time = jiffies;
	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 (rc && !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 && !cfid->has_lease) {
		/*
		 * We are guaranteed to have two references at this point.
		 * One for the caller and one for a potential lease.
		 * Release the Lease-ref so that the directory will be closed
		 * when the caller closes the cached handle.
		 */
		kref_put(&cfid->refcount, smb2_close_cached_fid);
	}
	if (rc) {
		if (cfid->is_open)
			SMB2_close(0, cfid->tcon, cfid->fid.persistent_fid,
				   cfid->fid.volatile_fid);
		free_cached_dir(cfid);
		cfid = NULL;
	}

	if (rc == 0) {
		*ret_cfid = cfid;
		atomic_inc(&tcon->num_remote_opens);
	}

	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);
		atomic_dec(&cfid->tcon->num_remote_opens);
	}

	free_cached_dir(cfid);
}

void drop_cached_dir_by_name(const unsigned int xid, struct cifs_tcon *tcon,
			     const char *name, struct cifs_sb_info *cifs_sb)
{
	struct cached_fid *cfid = NULL;
	int rc;

	rc = open_cached_dir(xid, tcon, name, cifs_sb, true, &cfid);
	if (rc) {
		cifs_dbg(FYI, "no cached dir found for rmdir(%s)\n", name);
		return;
	}
	spin_lock(&cfid->cfids->cfid_list_lock);
	if (cfid->has_lease) {
		cfid->has_lease = false;
		kref_put(&cfid->refcount, smb2_close_cached_fid);
	}
	spin_unlock(&cfid->cfids->cfid_list_lock);
	close_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;
	LIST_HEAD(entry);

	spin_lock(&cfids->cfid_list_lock);
	list_for_each_entry_safe(cfid, q, &cfids->entries, entry) {
		list_move(&cfid->entry, &entry);
		cfids->num_entries--;
		cfid->is_open = false;
		cfid->on_list = 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) {
		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;
	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_move(&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);
}
Commit	Line	Data
05b98fd2 RS	1	// SPDX-License-Identifier: GPL-2.0
	2	/*
	3	* Functions to handle the cached directory entries
	4	*
	5	* Copyright (c) 2022, Ronnie Sahlberg <lsahlber@redhat.com>
	6	*/
	7
e4029e07	8	#include <linux/namei.h>
05b98fd2 RS	9	#include "cifsglob.h"
	10	#include "cifsproto.h"
	11	#include "cifs_debug.h"
	12	#include "smb2proto.h"
	13	#include "cached_dir.h"
	14
ebe98f14 RS	15	static struct cached_fid init_cached_dir(const char path);
ebe98f14 RS	16	static void free_cached_dir(struct cached_fid *cfid);
8e843bf3	17	static void smb2_close_cached_fid(struct kref *ref);
ebe98f14 RS	18
	19	static struct cached_fid find_or_create_cached_dir(struct cached_fids cfids,
	20	const char *path,
	21	bool lookup_only)
	22	{
	23	struct cached_fid *cfid;
	24
	25	spin_lock(&cfids->cfid_list_lock);
	26	list_for_each_entry(cfid, &cfids->entries, entry) {
	27	if (!strcmp(cfid->path, path)) {
	28	/*
	29	* If it doesn't have a lease it is either not yet
	30	* fully cached or it may be in the process of
	31	* being deleted due to a lease break.
	32	*/
	33	if (!cfid->has_lease) {
	34	spin_unlock(&cfids->cfid_list_lock);
	35	return NULL;
	36	}
	37	kref_get(&cfid->refcount);
	38	spin_unlock(&cfids->cfid_list_lock);
	39	return cfid;
	40	}
	41	}
	42	if (lookup_only) {
	43	spin_unlock(&cfids->cfid_list_lock);
	44	return NULL;
	45	}
	46	if (cfids->num_entries >= MAX_CACHED_FIDS) {
	47	spin_unlock(&cfids->cfid_list_lock);
	48	return NULL;
	49	}
	50	cfid = init_cached_dir(path);
	51	if (cfid == NULL) {
	52	spin_unlock(&cfids->cfid_list_lock);
	53	return NULL;
	54	}
	55	cfid->cfids = cfids;
	56	cfids->num_entries++;
	57	list_add(&cfid->entry, &cfids->entries);
	58	cfid->on_list = true;
	59	kref_get(&cfid->refcount);
	60	spin_unlock(&cfids->cfid_list_lock);
	61	return cfid;
	62	}
30f8f371	63
e4029e07 RS	64	static struct dentry *
	65	path_to_dentry(struct cifs_sb_info cifs_sb, const char path)
	66	{
	67	struct dentry *dentry;
	68	const char s, p;
	69	char sep;
	70
	71	sep = CIFS_DIR_SEP(cifs_sb);
	72	dentry = dget(cifs_sb->root);
	73	s = path;
	74
	75	do {
	76	struct inode *dir = d_inode(dentry);
	77	struct dentry *child;
	78
	79	if (!S_ISDIR(dir->i_mode)) {
	80	dput(dentry);
	81	dentry = ERR_PTR(-ENOTDIR);
	82	break;
	83	}
	84
	85	/* skip separators */
	86	while (*s == sep)
	87	s++;
	88	if (!*s)
	89	break;
	90	p = s++;
	91	/* next separator */
	92	while (s && s != sep)
	93	s++;
	94
	95	child = lookup_positive_unlocked(p, dentry, s - p);
	96	dput(dentry);
	97	dentry = child;
	98	} while (!IS_ERR(dentry));
	99	return dentry;
	100	}
	101
be4fde79 PA	102	static const char path_no_prefix(struct cifs_sb_info cifs_sb,
	103	const char *path)
	104	{
	105	size_t len = 0;
	106
	107	if (!*path)
	108	return path;
	109
	110	if ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_USE_PREFIX_PATH) &&
	111	cifs_sb->prepath) {
	112	len = strlen(cifs_sb->prepath) + 1;
	113	if (unlikely(len > strlen(path)))
	114	return ERR_PTR(-EINVAL);
	115	}
	116	return path + len;
	117	}
	118
05b98fd2 RS	119	/*
	120	* Open the and cache a directory handle.
	121	* If error then *cfid is not initialized.
	122	*/
	123	int open_cached_dir(unsigned int xid, struct cifs_tcon *tcon,
7eb59a98 RS	124	const char *path,
	125	struct cifs_sb_info *cifs_sb,
	126	bool lookup_only, struct cached_fid **ret_cfid)
05b98fd2 RS	127	{
	128	struct cifs_ses *ses;
	129	struct TCP_Server_Info *server;
	130	struct cifs_open_parms oparms;
	131	struct smb2_create_rsp *o_rsp = NULL;
	132	struct smb2_query_info_rsp *qi_rsp = NULL;
	133	int resp_buftype[2];
	134	struct smb_rqst rqst[2];
	135	struct kvec rsp_iov[2];
	136	struct kvec open_iov[SMB2_CREATE_IOV_SIZE];
	137	struct kvec qi_iov[1];
	138	int rc, flags = 0;
ebe98f14	139	__le16 *utf16_path = NULL;
05b98fd2 RS	140	u8 oplock = SMB2_OPLOCK_LEVEL_II;
05b98fd2 RS	141	struct cifs_fid *pfid;
ebe98f14	142	struct dentry *dentry = NULL;
a63ec83c	143	struct cached_fid *cfid;
ebe98f14	144	struct cached_fids *cfids;
be4fde79	145	const char *npath;
05b98fd2	146
ebe98f14	147	if (tcon == NULL \|\| tcon->cfids == NULL \|\| tcon->nohandlecache \|\|
05b98fd2 RS	148	is_smb1_server(tcon->ses->server))
	149	return -EOPNOTSUPP;
	150
	151	ses = tcon->ses;
	152	server = ses->server;
ebe98f14 RS	153	cfids = tcon->cfids;
	154
	155	if (!server->ops->new_lease_key)
	156	return -EIO;
05b98fd2 RS	157
	158	if (cifs_sb->root == NULL)
	159	return -ENOENT;
	160
ebe98f14 RS	161	utf16_path = cifs_convert_path_to_utf16(path, cifs_sb);
ebe98f14 RS	162	if (!utf16_path)
30f8f371 RS	163	return -ENOMEM;
30f8f371 RS	164
ebe98f14 RS	165	cfid = find_or_create_cached_dir(cfids, path, lookup_only);
	166	if (cfid == NULL) {
	167	kfree(utf16_path);
	168	return -ENOENT;
	169	}
	170	/*
	171	* At this point we either have a lease already and we can just
	172	* return it. If not we are guaranteed to be the only thread accessing
	173	* this cfid.
	174	*/
	175	if (cfid->has_lease) {
a63ec83c	176	*ret_cfid = cfid;
ebe98f14	177	kfree(utf16_path);
05b98fd2 RS	178	return 0;
	179	}
	180
be4fde79 PA	181	/*
	182	* Skip any prefix paths in @path as lookup_positive_unlocked() ends up
	183	* calling ->lookup() which already adds those through
	184	* build_path_from_dentry(). Also, do it earlier as we might reconnect
	185	* below when trying to send compounded request and then potentially
	186	* having a different prefix path (e.g. after DFS failover).
	187	*/
	188	npath = path_no_prefix(cifs_sb, path);
	189	if (IS_ERR(npath)) {
	190	rc = PTR_ERR(npath);
	191	kfree(utf16_path);
	192	return rc;
	193	}
	194
05b98fd2 RS	195	/*
05b98fd2 RS	196	* We do not hold the lock for the open because in case
ebe98f14 RS	197	* SMB2_open needs to reconnect.
	198	* This is safe because no other thread will be able to get a ref
	199	* to the cfid until we have finished opening the file and (possibly)
	200	* acquired a lease.
05b98fd2	201	*/
05b98fd2 RS	202	if (smb3_encryption_required(tcon))
	203	flags \|= CIFS_TRANSFORM_REQ;
	204
a63ec83c	205	pfid = &cfid->fid;
05b98fd2 RS	206	server->ops->new_lease_key(pfid);
	207
	208	memset(rqst, 0, sizeof(rqst));
	209	resp_buftype[0] = resp_buftype[1] = CIFS_NO_BUFFER;
	210	memset(rsp_iov, 0, sizeof(rsp_iov));
	211
	212	/* Open */
	213	memset(&open_iov, 0, sizeof(open_iov));
	214	rqst[0].rq_iov = open_iov;
	215	rqst[0].rq_nvec = SMB2_CREATE_IOV_SIZE;
	216
de036dca VL	217	oparms = (struct cifs_open_parms) {
de036dca VL	218	.tcon = tcon,
fddc6ccc	219	.path = path,
de036dca VL	220	.create_options = cifs_create_options(cifs_sb, CREATE_NOT_FILE),
	221	.desired_access = FILE_READ_ATTRIBUTES,
	222	.disposition = FILE_OPEN,
	223	.fid = pfid,
	224	};
05b98fd2 RS	225
05b98fd2 RS	226	rc = SMB2_open_init(tcon, server,
ebe98f14	227	&rqst[0], &oplock, &oparms, utf16_path);
05b98fd2 RS	228	if (rc)
	229	goto oshr_free;
	230	smb2_set_next_command(tcon, &rqst[0]);
	231
	232	memset(&qi_iov, 0, sizeof(qi_iov));
	233	rqst[1].rq_iov = qi_iov;
	234	rqst[1].rq_nvec = 1;
	235
	236	rc = SMB2_query_info_init(tcon, server,
	237	&rqst[1], COMPOUND_FID,
	238	COMPOUND_FID, FILE_ALL_INFORMATION,
	239	SMB2_O_INFO_FILE, 0,
	240	sizeof(struct smb2_file_all_info) +
	241	PATH_MAX * 2, 0, NULL);
	242	if (rc)
	243	goto oshr_free;
	244
	245	smb2_set_related(&rqst[1]);
	246
	247	rc = compound_send_recv(xid, ses, server,
	248	flags, 2, rqst,
	249	resp_buftype, rsp_iov);
05b98fd2 RS	250	if (rc) {
	251	if (rc == -EREMCHG) {
	252	tcon->need_reconnect = true;
	253	pr_warn_once("server share %s deleted\n",
68e14569	254	tcon->tree_name);
05b98fd2	255	}
ebe98f14	256	goto oshr_free;
05b98fd2	257	}
8e843bf3	258	cfid->tcon = tcon;
66d45ca1	259	cfid->is_open = true;
05b98fd2 RS	260
	261	o_rsp = (struct smb2_create_rsp *)rsp_iov[0].iov_base;
	262	oparms.fid->persistent_fid = o_rsp->PersistentFileId;
	263	oparms.fid->volatile_fid = o_rsp->VolatileFileId;
	264	#ifdef CONFIG_CIFS_DEBUG2
	265	oparms.fid->mid = le64_to_cpu(o_rsp->hdr.MessageId);
	266	#endif /* CIFS_DEBUG2 */
	267
ebe98f14 RS	268	if (o_rsp->OplockLevel != SMB2_OPLOCK_LEVEL_LEASE)
	269	goto oshr_free;
	270
ebe98f14 RS	271	smb2_parse_contexts(server, o_rsp,
	272	&oparms.fid->epoch,
	273	oparms.fid->lease_key, &oplock,
	274	NULL, NULL);
66d45ca1 RS	275	if (!(oplock & SMB2_LEASE_READ_CACHING_HE))
66d45ca1 RS	276	goto oshr_free;
05b98fd2 RS	277	qi_rsp = (struct smb2_query_info_rsp *)rsp_iov[1].iov_base;
05b98fd2 RS	278	if (le32_to_cpu(qi_rsp->OutputBufferLength) < sizeof(struct smb2_file_all_info))
ebe98f14	279	goto oshr_free;
05b98fd2 RS	280	if (!smb2_validate_and_copy_iov(
	281	le16_to_cpu(qi_rsp->OutputBufferOffset),
	282	sizeof(struct smb2_file_all_info),
	283	&rsp_iov[1], sizeof(struct smb2_file_all_info),
a63ec83c RS	284	(char *)&cfid->file_all_info))
a63ec83c RS	285	cfid->file_all_info_is_valid = true;
e4029e07	286
be4fde79	287	if (!npath[0])
e4029e07 RS	288	dentry = dget(cifs_sb->root);
e4029e07 RS	289	else {
be4fde79	290	dentry = path_to_dentry(cifs_sb, npath);
053569cc RS	291	if (IS_ERR(dentry)) {
053569cc RS	292	rc = -ENOENT;
e4029e07	293	goto oshr_free;
053569cc	294	}
e4029e07 RS	295	}
e4029e07 RS	296	cfid->dentry = dentry;
a63ec83c	297	cfid->time = jiffies;
ebe98f14	298	cfid->has_lease = true;
05b98fd2	299
05b98fd2	300	oshr_free:
ebe98f14	301	kfree(utf16_path);
05b98fd2 RS	302	SMB2_open_free(&rqst[0]);
	303	SMB2_query_info_free(&rqst[1]);
	304	free_rsp_buf(resp_buftype[0], rsp_iov[0].iov_base);
	305	free_rsp_buf(resp_buftype[1], rsp_iov[1].iov_base);
ebe98f14	306	spin_lock(&cfids->cfid_list_lock);
8e843bf3	307	if (rc && !cfid->has_lease) {
ebe98f14 RS	308	if (cfid->on_list) {
	309	list_del(&cfid->entry);
	310	cfid->on_list = false;
	311	cfids->num_entries--;
	312	}
	313	rc = -ENOENT;
	314	}
	315	spin_unlock(&cfids->cfid_list_lock);
8e843bf3 RS	316	if (!rc && !cfid->has_lease) {
	317	/*
	318	* We are guaranteed to have two references at this point.
	319	* One for the caller and one for a potential lease.
	320	* Release the Lease-ref so that the directory will be closed
	321	* when the caller closes the cached handle.
	322	*/
	323	kref_put(&cfid->refcount, smb2_close_cached_fid);
	324	}
ebe98f14	325	if (rc) {
66d45ca1 RS	326	if (cfid->is_open)
	327	SMB2_close(0, cfid->tcon, cfid->fid.persistent_fid,
	328	cfid->fid.volatile_fid);
ebe98f14 RS	329	free_cached_dir(cfid);
	330	cfid = NULL;
	331	}
	332
66d45ca1	333	if (rc == 0) {
a63ec83c	334	*ret_cfid = cfid;
66d45ca1 RS	335	atomic_inc(&tcon->num_remote_opens);
66d45ca1 RS	336	}
05b98fd2 RS	337
	338	return rc;
	339	}
	340
	341	int open_cached_dir_by_dentry(struct cifs_tcon *tcon,
	342	struct dentry *dentry,
a63ec83c	343	struct cached_fid **ret_cfid)
05b98fd2	344	{
a63ec83c	345	struct cached_fid *cfid;
ebe98f14	346	struct cached_fids *cfids = tcon->cfids;
a63ec83c	347
ebe98f14	348	if (cfids == NULL)
30f8f371	349	return -ENOENT;
a63ec83c	350
ebe98f14 RS	351	spin_lock(&cfids->cfid_list_lock);
	352	list_for_each_entry(cfid, &cfids->entries, entry) {
	353	if (dentry && cfid->dentry == dentry) {
	354	cifs_dbg(FYI, "found a cached root file handle by dentry\n");
	355	kref_get(&cfid->refcount);
	356	*ret_cfid = cfid;
	357	spin_unlock(&cfids->cfid_list_lock);
	358	return 0;
	359	}
05b98fd2	360	}
ebe98f14	361	spin_unlock(&cfids->cfid_list_lock);
05b98fd2 RS	362	return -ENOENT;
	363	}
	364
	365	static void
	366	smb2_close_cached_fid(struct kref *ref)
	367	{
	368	struct cached_fid *cfid = container_of(ref, struct cached_fid,
	369	refcount);
05b98fd2	370
ebe98f14 RS	371	spin_lock(&cfid->cfids->cfid_list_lock);
	372	if (cfid->on_list) {
	373	list_del(&cfid->entry);
	374	cfid->on_list = false;
	375	cfid->cfids->num_entries--;
05b98fd2	376	}
ebe98f14	377	spin_unlock(&cfid->cfids->cfid_list_lock);
05b98fd2	378
ebe98f14 RS	379	dput(cfid->dentry);
	380	cfid->dentry = NULL;
	381
	382	if (cfid->is_open) {
	383	SMB2_close(0, cfid->tcon, cfid->fid.persistent_fid,
	384	cfid->fid.volatile_fid);
8e843bf3	385	atomic_dec(&cfid->tcon->num_remote_opens);
05b98fd2	386	}
05b98fd2	387
ebe98f14	388	free_cached_dir(cfid);
05b98fd2 RS	389	}
05b98fd2 RS	390
8e77860c RS	391	void drop_cached_dir_by_name(const unsigned int xid, struct cifs_tcon *tcon,
	392	const char name, struct cifs_sb_info cifs_sb)
	393	{
	394	struct cached_fid *cfid = NULL;
	395	int rc;
	396
	397	rc = open_cached_dir(xid, tcon, name, cifs_sb, true, &cfid);
	398	if (rc) {
	399	cifs_dbg(FYI, "no cached dir found for rmdir(%s)\n", name);
	400	return;
	401	}
	402	spin_lock(&cfid->cfids->cfid_list_lock);
	403	if (cfid->has_lease) {
	404	cfid->has_lease = false;
	405	kref_put(&cfid->refcount, smb2_close_cached_fid);
	406	}
	407	spin_unlock(&cfid->cfids->cfid_list_lock);
	408	close_cached_dir(cfid);
	409	}
	410
	411
05b98fd2 RS	412	void close_cached_dir(struct cached_fid *cfid)
05b98fd2 RS	413	{
05b98fd2	414	kref_put(&cfid->refcount, smb2_close_cached_fid);
05b98fd2 RS	415	}
	416
	417	/*
	418	* Called from cifs_kill_sb when we unmount a share
	419	*/
	420	void close_all_cached_dirs(struct cifs_sb_info *cifs_sb)
	421	{
	422	struct rb_root *root = &cifs_sb->tlink_tree;
	423	struct rb_node *node;
	424	struct cached_fid *cfid;
	425	struct cifs_tcon *tcon;
	426	struct tcon_link *tlink;
ebe98f14	427	struct cached_fids *cfids;
05b98fd2 RS	428
	429	for (node = rb_first(root); node; node = rb_next(node)) {
	430	tlink = rb_entry(node, struct tcon_link, tl_rbnode);
	431	tcon = tlink_tcon(tlink);
	432	if (IS_ERR(tcon))
	433	continue;
ebe98f14 RS	434	cfids = tcon->cfids;
ebe98f14 RS	435	if (cfids == NULL)
30f8f371	436	continue;
ebe98f14	437	list_for_each_entry(cfid, &cfids->entries, entry) {
05b98fd2 RS	438	dput(cfid->dentry);
	439	cfid->dentry = NULL;
	440	}
05b98fd2 RS	441	}
	442	}
	443
	444	/*
ebe98f14	445	* Invalidate all cached dirs when a TCON has been reset
05b98fd2 RS	446	* due to a session loss.
	447	*/
	448	void invalidate_all_cached_dirs(struct cifs_tcon *tcon)
	449	{
ebe98f14 RS	450	struct cached_fids *cfids = tcon->cfids;
ebe98f14 RS	451	struct cached_fid cfid, q;
d32f211a	452	LIST_HEAD(entry);
ebe98f14	453
ebe98f14 RS	454	spin_lock(&cfids->cfid_list_lock);
ebe98f14 RS	455	list_for_each_entry_safe(cfid, q, &cfids->entries, entry) {
d32f211a	456	list_move(&cfid->entry, &entry);
ebe98f14 RS	457	cfids->num_entries--;
ebe98f14 RS	458	cfid->is_open = false;
053569cc	459	cfid->on_list = false;
ebe98f14 RS	460	/* To prevent race with smb2_cached_lease_break() */
	461	kref_get(&cfid->refcount);
	462	}
	463	spin_unlock(&cfids->cfid_list_lock);
	464
	465	list_for_each_entry_safe(cfid, q, &entry, entry) {
ebe98f14 RS	466	list_del(&cfid->entry);
	467	cancel_work_sync(&cfid->lease_break);
	468	if (cfid->has_lease) {
	469	/*
	470	* We lease was never cancelled from the server so we
	471	* need to drop the reference.
	472	*/
	473	spin_lock(&cfids->cfid_list_lock);
	474	cfid->has_lease = false;
	475	spin_unlock(&cfids->cfid_list_lock);
	476	kref_put(&cfid->refcount, smb2_close_cached_fid);
	477	}
	478	/* Drop the extra reference opened above*/
	479	kref_put(&cfid->refcount, smb2_close_cached_fid);
	480	}
05b98fd2 RS	481	}
	482
	483	static void
	484	smb2_cached_lease_break(struct work_struct *work)
	485	{
	486	struct cached_fid *cfid = container_of(work,
	487	struct cached_fid, lease_break);
	488
ebe98f14 RS	489	spin_lock(&cfid->cfids->cfid_list_lock);
	490	cfid->has_lease = false;
	491	spin_unlock(&cfid->cfids->cfid_list_lock);
	492	kref_put(&cfid->refcount, smb2_close_cached_fid);
05b98fd2 RS	493	}
	494
	495	int cached_dir_lease_break(struct cifs_tcon *tcon, __u8 lease_key[16])
	496	{
ebe98f14 RS	497	struct cached_fids *cfids = tcon->cfids;
ebe98f14 RS	498	struct cached_fid *cfid;
30f8f371	499
ebe98f14	500	if (cfids == NULL)
30f8f371	501	return false;
aea6794e	502
ebe98f14 RS	503	spin_lock(&cfids->cfid_list_lock);
	504	list_for_each_entry(cfid, &cfids->entries, entry) {
	505	if (cfid->has_lease &&
	506	!memcmp(lease_key,
	507	cfid->fid.lease_key,
	508	SMB2_LEASE_KEY_SIZE)) {
	509	cfid->time = 0;
	510	/*
	511	* We found a lease remove it from the list
	512	* so no threads can access it.
	513	*/
	514	list_del(&cfid->entry);
	515	cfid->on_list = false;
	516	cfids->num_entries--;
	517
	518	queue_work(cifsiod_wq,
	519	&cfid->lease_break);
	520	spin_unlock(&cfids->cfid_list_lock);
	521	return true;
	522	}
05b98fd2	523	}
ebe98f14	524	spin_unlock(&cfids->cfid_list_lock);
05b98fd2 RS	525	return false;
05b98fd2 RS	526	}
a63ec83c	527
ebe98f14	528	static struct cached_fid init_cached_dir(const char path)
30f8f371 RS	529	{
	530	struct cached_fid *cfid;
	531
ebe98f14	532	cfid = kzalloc(sizeof(*cfid), GFP_ATOMIC);
30f8f371 RS	533	if (!cfid)
30f8f371 RS	534	return NULL;
ebe98f14	535	cfid->path = kstrdup(path, GFP_ATOMIC);
30f8f371 RS	536	if (!cfid->path) {
	537	kfree(cfid);
	538	return NULL;
	539	}
	540
ebe98f14 RS	541	INIT_WORK(&cfid->lease_break, smb2_cached_lease_break);
ebe98f14 RS	542	INIT_LIST_HEAD(&cfid->entry);
30f8f371 RS	543	INIT_LIST_HEAD(&cfid->dirents.entries);
30f8f371 RS	544	mutex_init(&cfid->dirents.de_mutex);
ebe98f14 RS	545	spin_lock_init(&cfid->fid_lock);
ebe98f14 RS	546	kref_init(&cfid->refcount);
30f8f371 RS	547	return cfid;
	548	}
	549
ebe98f14	550	static void free_cached_dir(struct cached_fid *cfid)
30f8f371	551	{
ebe98f14 RS	552	struct cached_dirent dirent, q;
	553
	554	dput(cfid->dentry);
	555	cfid->dentry = NULL;
	556
	557	/*
	558	* Delete all cached dirent names
	559	*/
	560	list_for_each_entry_safe(dirent, q, &cfid->dirents.entries, entry) {
	561	list_del(&dirent->entry);
	562	kfree(dirent->name);
	563	kfree(dirent);
	564	}
	565
30f8f371 RS	566	kfree(cfid->path);
	567	cfid->path = NULL;
	568	kfree(cfid);
	569	}
	570
aea6794e	571	struct cached_fids *init_cached_dirs(void)
a63ec83c	572	{
aea6794e	573	struct cached_fids *cfids;
a63ec83c	574
aea6794e RS	575	cfids = kzalloc(sizeof(*cfids), GFP_KERNEL);
aea6794e RS	576	if (!cfids)
a63ec83c	577	return NULL;
ebe98f14 RS	578	spin_lock_init(&cfids->cfid_list_lock);
ebe98f14 RS	579	INIT_LIST_HEAD(&cfids->entries);
aea6794e	580	return cfids;
a63ec83c RS	581	}
a63ec83c RS	582
ebe98f14 RS	583	/*
	584	* Called from tconInfoFree when we are tearing down the tcon.
	585	* There are no active users or open files/directories at this point.
	586	*/
aea6794e	587	void free_cached_dirs(struct cached_fids *cfids)
a63ec83c	588	{
ebe98f14	589	struct cached_fid cfid, q;
d32f211a	590	LIST_HEAD(entry);
ebe98f14	591
ebe98f14 RS	592	spin_lock(&cfids->cfid_list_lock);
	593	list_for_each_entry_safe(cfid, q, &cfids->entries, entry) {
	594	cfid->on_list = false;
	595	cfid->is_open = false;
d32f211a	596	list_move(&cfid->entry, &entry);
30f8f371	597	}
ebe98f14 RS	598	spin_unlock(&cfids->cfid_list_lock);
	599
	600	list_for_each_entry_safe(cfid, q, &entry, entry) {
	601	list_del(&cfid->entry);
	602	free_cached_dir(cfid);
	603	}
	604
aea6794e	605	kfree(cfids);
a63ec83c	606	}