linux/fs/cifs/cached_dir.c
Ronnie Sahlberg 7eb59a9870 cifs: Do not access tcon->cfids->cfid directly from is_path_accessible
cfids will soon keep a list of cached fids so we should not access this
directly from outside of cached_dir.c

Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2022-08-12 17:40:15 -05:00

389 lines
9.3 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Functions to handle the cached directory entries
*
* Copyright (c) 2022, Ronnie Sahlberg <lsahlber@redhat.com>
*/
#include "cifsglob.h"
#include "cifsproto.h"
#include "cifs_debug.h"
#include "smb2proto.h"
#include "cached_dir.h"
/*
* 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 = 0; /* Null - since an open of top of share */
u8 oplock = SMB2_OPLOCK_LEVEL_II;
struct cifs_fid *pfid;
struct dentry *dentry;
struct cached_fid *cfid;
if (tcon == NULL || tcon->nohandlecache ||
is_smb1_server(tcon->ses->server))
return -EOPNOTSUPP;
ses = tcon->ses;
server = ses->server;
if (cifs_sb->root == NULL)
return -ENOENT;
if (strlen(path))
return -ENOENT;
dentry = cifs_sb->root;
cfid = tcon->cfid;
mutex_lock(&cfid->fid_mutex);
if (cfid->is_valid) {
cifs_dbg(FYI, "found a cached root file handle\n");
*ret_cfid = cfid;
kref_get(&cfid->refcount);
mutex_unlock(&cfid->fid_mutex);
return 0;
}
/*
* We do not hold the lock for the open because in case
* SMB2_open needs to reconnect, it will end up calling
* cifs_mark_open_files_invalid() which takes the lock again
* thus causing a deadlock
*/
mutex_unlock(&cfid->fid_mutex);
if (lookup_only)
return -ENOENT;
if (smb3_encryption_required(tcon))
flags |= CIFS_TRANSFORM_REQ;
if (!server->ops->new_lease_key)
return -EIO;
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);
mutex_lock(&cfid->fid_mutex);
/*
* Now we need to check again as the cached root might have
* been successfully re-opened from a concurrent process
*/
if (cfid->is_valid) {
/* work was already done */
/* stash fids for close() later */
struct cifs_fid fid = {
.persistent_fid = pfid->persistent_fid,
.volatile_fid = pfid->volatile_fid,
};
/*
* caller expects this func to set the fid in cfid to valid
* cached root, so increment the refcount.
*/
kref_get(&cfid->refcount);
mutex_unlock(&cfid->fid_mutex);
if (rc == 0) {
/* close extra handle outside of crit sec */
SMB2_close(xid, tcon, fid.persistent_fid, fid.volatile_fid);
}
rc = 0;
goto oshr_free;
}
/* Cached root is still invalid, continue normaly */
if (rc) {
if (rc == -EREMCHG) {
tcon->need_reconnect = true;
pr_warn_once("server share %s deleted\n",
tcon->treeName);
}
goto oshr_exit;
}
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 */
cfid->tcon = tcon;
cfid->is_valid = true;
cfid->dentry = dentry;
dget(dentry);
kref_init(&cfid->refcount);
/* BB TBD check to see if oplock level check can be removed below */
if (o_rsp->OplockLevel == SMB2_OPLOCK_LEVEL_LEASE) {
/*
* See commit 2f94a3125b87. Increment the refcount when we
* get a lease for root, release it if lease break occurs
*/
kref_get(&cfid->refcount);
cfid->has_lease = true;
smb2_parse_contexts(server, o_rsp,
&oparms.fid->epoch,
oparms.fid->lease_key, &oplock,
NULL, NULL);
} else
goto oshr_exit;
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_exit;
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;
cfid->time = jiffies;
oshr_exit:
mutex_unlock(&cfid->fid_mutex);
oshr_free:
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);
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;
cfid = tcon->cfid;
mutex_lock(&cfid->fid_mutex);
if (cfid->dentry == dentry) {
cifs_dbg(FYI, "found a cached root file handle by dentry\n");
*ret_cfid = cfid;
kref_get(&cfid->refcount);
mutex_unlock(&cfid->fid_mutex);
return 0;
}
mutex_unlock(&cfid->fid_mutex);
return -ENOENT;
}
static void
smb2_close_cached_fid(struct kref *ref)
{
struct cached_fid *cfid = container_of(ref, struct cached_fid,
refcount);
struct cached_dirent *dirent, *q;
if (cfid->is_valid) {
cifs_dbg(FYI, "clear cached root file handle\n");
SMB2_close(0, cfid->tcon, cfid->fid.persistent_fid,
cfid->fid.volatile_fid);
}
/*
* We only check validity above to send SMB2_close,
* but we still need to invalidate these entries
* when this function is called
*/
cfid->is_valid = false;
cfid->file_all_info_is_valid = false;
cfid->has_lease = false;
if (cfid->dentry) {
dput(cfid->dentry);
cfid->dentry = NULL;
}
/*
* Delete all cached dirent names
*/
mutex_lock(&cfid->dirents.de_mutex);
list_for_each_entry_safe(dirent, q, &cfid->dirents.entries, entry) {
list_del(&dirent->entry);
kfree(dirent->name);
kfree(dirent);
}
cfid->dirents.is_valid = 0;
cfid->dirents.is_failed = 0;
cfid->dirents.ctx = NULL;
cfid->dirents.pos = 0;
mutex_unlock(&cfid->dirents.de_mutex);
}
void close_cached_dir(struct cached_fid *cfid)
{
mutex_lock(&cfid->fid_mutex);
kref_put(&cfid->refcount, smb2_close_cached_fid);
mutex_unlock(&cfid->fid_mutex);
}
void close_cached_dir_lease_locked(struct cached_fid *cfid)
{
if (cfid->has_lease) {
cfid->has_lease = false;
kref_put(&cfid->refcount, smb2_close_cached_fid);
}
}
void close_cached_dir_lease(struct cached_fid *cfid)
{
mutex_lock(&cfid->fid_mutex);
close_cached_dir_lease_locked(cfid);
mutex_unlock(&cfid->fid_mutex);
}
/*
* 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;
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;
cfid = tcon->cfid;
mutex_lock(&cfid->fid_mutex);
if (cfid->dentry) {
dput(cfid->dentry);
cfid->dentry = NULL;
}
mutex_unlock(&cfid->fid_mutex);
}
}
/*
* Invalidate and close all cached dirs when a TCON has been reset
* due to a session loss.
*/
void invalidate_all_cached_dirs(struct cifs_tcon *tcon)
{
mutex_lock(&tcon->cfid->fid_mutex);
tcon->cfid->is_valid = false;
/* cached handle is not valid, so SMB2_CLOSE won't be sent below */
close_cached_dir_lease_locked(tcon->cfid);
memset(&tcon->cfid->fid, 0, sizeof(struct cifs_fid));
mutex_unlock(&tcon->cfid->fid_mutex);
}
static void
smb2_cached_lease_break(struct work_struct *work)
{
struct cached_fid *cfid = container_of(work,
struct cached_fid, lease_break);
close_cached_dir_lease(cfid);
}
int cached_dir_lease_break(struct cifs_tcon *tcon, __u8 lease_key[16])
{
if (tcon->cfid->is_valid &&
!memcmp(lease_key,
tcon->cfid->fid.lease_key,
SMB2_LEASE_KEY_SIZE)) {
tcon->cfid->time = 0;
INIT_WORK(&tcon->cfid->lease_break,
smb2_cached_lease_break);
queue_work(cifsiod_wq,
&tcon->cfid->lease_break);
return true;
}
return false;
}
struct cached_fid *init_cached_dir(void)
{
struct cached_fid *cfid;
cfid = kzalloc(sizeof(*cfid), GFP_KERNEL);
if (!cfid)
return NULL;
INIT_LIST_HEAD(&cfid->dirents.entries);
mutex_init(&cfid->dirents.de_mutex);
mutex_init(&cfid->fid_mutex);
return cfid;
}
void free_cached_dir(struct cifs_tcon *tcon)
{
kfree(tcon->cfid);
}