android_kernel_xiaomi_sm8350/fs/cifs/cifsglob.h
Steve French c16fefa563 [CIFS] distinguish between Kerberos and MSKerberos in upcall
Properly handle MSKRB5 by passing sec=mskrb5 to the upcall so that the
spengo blob can be generated appropriately. Also, make
decode_negTokenInit prefer whichever mechanism is first in the list.

Needed for some NetApp servers, and possibly some older
versions of Windows which treat the two KRB5 mechanisms differently.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2008-08-19 19:35:33 +00:00

655 lines
22 KiB
C

/*
* fs/cifs/cifsglob.h
*
* Copyright (C) International Business Machines Corp., 2002,2008
* Author(s): Steve French (sfrench@us.ibm.com)
* Jeremy Allison (jra@samba.org)
*
* This library is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published
* by the Free Software Foundation; either version 2.1 of the License, or
* (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
* the GNU Lesser General Public License for more details.
*
*/
#include <linux/in.h>
#include <linux/in6.h>
#include "cifs_fs_sb.h"
#include "cifsacl.h"
/*
* The sizes of various internal tables and strings
*/
#define MAX_UID_INFO 16
#define MAX_SES_INFO 2
#define MAX_TCON_INFO 4
#define MAX_TREE_SIZE (2 + MAX_SERVER_SIZE + 1 + MAX_SHARE_SIZE + 1)
#define MAX_SERVER_SIZE 15
#define MAX_SHARE_SIZE 64 /* used to be 20, this should still be enough */
#define MAX_USERNAME_SIZE 32 /* 32 is to allow for 15 char names + null
termination then *2 for unicode versions */
#define MAX_PASSWORD_SIZE 16
#define CIFS_MIN_RCV_POOL 4
/*
* MAX_REQ is the maximum number of requests that WE will send
* on one socket concurently. It also matches the most common
* value of max multiplex returned by servers. We may
* eventually want to use the negotiated value (in case
* future servers can handle more) when we are more confident that
* we will not have problems oveloading the socket with pending
* write data.
*/
#define CIFS_MAX_REQ 50
#define SERVER_NAME_LENGTH 15
#define SERVER_NAME_LEN_WITH_NULL (SERVER_NAME_LENGTH + 1)
/* used to define string lengths for reversing unicode strings */
/* (256+1)*2 = 514 */
/* (max path length + 1 for null) * 2 for unicode */
#define MAX_NAME 514
#include "cifspdu.h"
#ifndef XATTR_DOS_ATTRIB
#define XATTR_DOS_ATTRIB "user.DOSATTRIB"
#endif
/*
* CIFS vfs client Status information (based on what we know.)
*/
/* associated with each tcp and smb session */
enum statusEnum {
CifsNew = 0,
CifsGood,
CifsExiting,
CifsNeedReconnect
};
enum securityEnum {
PLAINTXT = 0, /* Legacy with Plaintext passwords */
LANMAN, /* Legacy LANMAN auth */
NTLM, /* Legacy NTLM012 auth with NTLM hash */
NTLMv2, /* Legacy NTLM auth with NTLMv2 hash */
RawNTLMSSP, /* NTLMSSP without SPNEGO */
NTLMSSP, /* NTLMSSP via SPNEGO */
Kerberos, /* Kerberos via SPNEGO */
MSKerberos, /* MS Kerberos via SPNEGO */
};
enum protocolEnum {
IPV4 = 0,
IPV6,
SCTP
/* Netbios frames protocol not supported at this time */
};
struct mac_key {
unsigned int len;
union {
char ntlm[CIFS_SESS_KEY_SIZE + 16];
char krb5[CIFS_SESS_KEY_SIZE + 16]; /* BB: length correct? */
struct {
char key[16];
struct ntlmv2_resp resp;
} ntlmv2;
} data;
};
struct cifs_cred {
int uid;
int gid;
int mode;
int cecount;
struct cifs_sid osid;
struct cifs_sid gsid;
struct cifs_ntace *ntaces;
struct cifs_ace *aces;
};
/*
*****************************************************************
* Except the CIFS PDUs themselves all the
* globally interesting structs should go here
*****************************************************************
*/
struct TCP_Server_Info {
/* 15 character server name + 0x20 16th byte indicating type = srv */
char server_RFC1001_name[SERVER_NAME_LEN_WITH_NULL];
char unicode_server_Name[SERVER_NAME_LEN_WITH_NULL * 2];
char *hostname; /* hostname portion of UNC string */
struct socket *ssocket;
union {
struct sockaddr_in sockAddr;
struct sockaddr_in6 sockAddr6;
} addr;
wait_queue_head_t response_q;
wait_queue_head_t request_q; /* if more than maxmpx to srvr must block*/
struct list_head pending_mid_q;
void *Server_NlsInfo; /* BB - placeholder for future NLS info */
unsigned short server_codepage; /* codepage for the server */
unsigned long ip_address; /* IP addr for the server if known */
enum protocolEnum protocolType;
char versionMajor;
char versionMinor;
bool svlocal:1; /* local server or remote */
atomic_t socketUseCount; /* number of open cifs sessions on socket */
atomic_t inFlight; /* number of requests on the wire to server */
#ifdef CONFIG_CIFS_STATS2
atomic_t inSend; /* requests trying to send */
atomic_t num_waiters; /* blocked waiting to get in sendrecv */
#endif
enum statusEnum tcpStatus; /* what we think the status is */
struct semaphore tcpSem;
struct task_struct *tsk;
char server_GUID[16];
char secMode;
enum securityEnum secType;
unsigned int maxReq; /* Clients should submit no more */
/* than maxReq distinct unanswered SMBs to the server when using */
/* multiplexed reads or writes */
unsigned int maxBuf; /* maxBuf specifies the maximum */
/* message size the server can send or receive for non-raw SMBs */
unsigned int maxRw; /* maxRw specifies the maximum */
/* message size the server can send or receive for */
/* SMB_COM_WRITE_RAW or SMB_COM_READ_RAW. */
char sessid[4]; /* unique token id for this session */
/* (returned on Negotiate */
int capabilities; /* allow selective disabling of caps by smb sess */
int timeAdj; /* Adjust for difference in server time zone in sec */
__u16 CurrentMid; /* multiplex id - rotating counter */
char cryptKey[CIFS_CRYPTO_KEY_SIZE];
/* 16th byte of RFC1001 workstation name is always null */
char workstation_RFC1001_name[SERVER_NAME_LEN_WITH_NULL];
__u32 sequence_number; /* needed for CIFS PDU signature */
struct mac_key mac_signing_key;
char ntlmv2_hash[16];
unsigned long lstrp; /* when we got last response from this server */
};
/*
* The following is our shortcut to user information. We surface the uid,
* and name. We always get the password on the fly in case it
* has changed. We also hang a list of sessions owned by this user off here.
*/
struct cifsUidInfo {
struct list_head userList;
struct list_head sessionList; /* SMB sessions for this user */
uid_t linux_uid;
char user[MAX_USERNAME_SIZE + 1]; /* ascii name of user */
/* BB may need ptr or callback for PAM or WinBind info */
};
/*
* Session structure. One of these for each uid session with a particular host
*/
struct cifsSesInfo {
struct list_head cifsSessionList;
struct semaphore sesSem;
#if 0
struct cifsUidInfo *uidInfo; /* pointer to user info */
#endif
struct TCP_Server_Info *server; /* pointer to server info */
atomic_t inUse; /* # of mounts (tree connections) on this ses */
enum statusEnum status;
unsigned overrideSecFlg; /* if non-zero override global sec flags */
__u16 ipc_tid; /* special tid for connection to IPC share */
__u16 flags;
char *serverOS; /* name of operating system underlying server */
char *serverNOS; /* name of network operating system of server */
char *serverDomain; /* security realm of server */
int Suid; /* remote smb uid */
uid_t linux_uid; /* local Linux uid */
int capabilities;
char serverName[SERVER_NAME_LEN_WITH_NULL * 2]; /* BB make bigger for
TCP names - will ipv6 and sctp addresses fit? */
char userName[MAX_USERNAME_SIZE + 1];
char *domainName;
char *password;
};
/* no more than one of the following three session flags may be set */
#define CIFS_SES_NT4 1
#define CIFS_SES_OS2 2
#define CIFS_SES_W9X 4
/* following flag is set for old servers such as OS2 (and Win95?)
which do not negotiate NTLM or POSIX dialects, but instead
negotiate one of the older LANMAN dialects */
#define CIFS_SES_LANMAN 8
/*
* there is one of these for each connection to a resource on a particular
* session
*/
struct cifsTconInfo {
struct list_head cifsConnectionList;
struct list_head openFileList;
struct semaphore tconSem;
struct cifsSesInfo *ses; /* pointer to session associated with */
char treeName[MAX_TREE_SIZE + 1]; /* UNC name of resource in ASCII */
char *nativeFileSystem;
__u16 tid; /* The 2 byte tree id */
__u16 Flags; /* optional support bits */
enum statusEnum tidStatus;
atomic_t useCount; /* how many explicit/implicit mounts to share */
#ifdef CONFIG_CIFS_STATS
atomic_t num_smbs_sent;
atomic_t num_writes;
atomic_t num_reads;
atomic_t num_oplock_brks;
atomic_t num_opens;
atomic_t num_closes;
atomic_t num_deletes;
atomic_t num_mkdirs;
atomic_t num_rmdirs;
atomic_t num_renames;
atomic_t num_t2renames;
atomic_t num_ffirst;
atomic_t num_fnext;
atomic_t num_fclose;
atomic_t num_hardlinks;
atomic_t num_symlinks;
atomic_t num_locks;
atomic_t num_acl_get;
atomic_t num_acl_set;
#ifdef CONFIG_CIFS_STATS2
unsigned long long time_writes;
unsigned long long time_reads;
unsigned long long time_opens;
unsigned long long time_deletes;
unsigned long long time_closes;
unsigned long long time_mkdirs;
unsigned long long time_rmdirs;
unsigned long long time_renames;
unsigned long long time_t2renames;
unsigned long long time_ffirst;
unsigned long long time_fnext;
unsigned long long time_fclose;
#endif /* CONFIG_CIFS_STATS2 */
__u64 bytes_read;
__u64 bytes_written;
spinlock_t stat_lock;
#endif /* CONFIG_CIFS_STATS */
FILE_SYSTEM_DEVICE_INFO fsDevInfo;
FILE_SYSTEM_ATTRIBUTE_INFO fsAttrInfo; /* ok if fs name truncated */
FILE_SYSTEM_UNIX_INFO fsUnixInfo;
bool ipc:1; /* set if connection to IPC$ eg for RPC/PIPES */
bool retry:1;
bool nocase:1;
bool seal:1; /* transport encryption for this mounted share */
bool unix_ext:1; /* if false disable Linux extensions to CIFS protocol
for this mount even if server would support */
/* BB add field for back pointer to sb struct(s)? */
};
/*
* This info hangs off the cifsFileInfo structure, pointed to by llist.
* This is used to track byte stream locks on the file
*/
struct cifsLockInfo {
struct list_head llist; /* pointer to next cifsLockInfo */
__u64 offset;
__u64 length;
__u8 type;
};
/*
* One of these for each open instance of a file
*/
struct cifs_search_info {
loff_t index_of_last_entry;
__u16 entries_in_buffer;
__u16 info_level;
__u32 resume_key;
char *ntwrk_buf_start;
char *srch_entries_start;
char *presume_name;
unsigned int resume_name_len;
bool endOfSearch:1;
bool emptyDir:1;
bool unicode:1;
bool smallBuf:1; /* so we know which buf_release function to call */
};
struct cifsFileInfo {
struct list_head tlist; /* pointer to next fid owned by tcon */
struct list_head flist; /* next fid (file instance) for this inode */
unsigned int uid; /* allows finding which FileInfo structure */
__u32 pid; /* process id who opened file */
__u16 netfid; /* file id from remote */
/* BB add lock scope info here if needed */ ;
/* lock scope id (0 if none) */
struct file *pfile; /* needed for writepage */
struct inode *pInode; /* needed for oplock break */
struct mutex lock_mutex;
struct list_head llist; /* list of byte range locks we have. */
bool closePend:1; /* file is marked to close */
bool invalidHandle:1; /* file closed via session abend */
bool messageMode:1; /* for pipes: message vs byte mode */
atomic_t wrtPending; /* handle in use - defer close */
struct semaphore fh_sem; /* prevents reopen race after dead ses*/
struct cifs_search_info srch_inf;
};
/*
* One of these for each file inode
*/
struct cifsInodeInfo {
struct list_head lockList;
/* BB add in lists for dirty pages i.e. write caching info for oplock */
struct list_head openFileList;
int write_behind_rc;
__u32 cifsAttrs; /* e.g. DOS archive bit, sparse, compressed, system */
atomic_t inUse; /* num concurrent users (local openers cifs) of file*/
unsigned long time; /* jiffies of last update/check of inode */
bool clientCanCacheRead:1; /* read oplock */
bool clientCanCacheAll:1; /* read and writebehind oplock */
bool oplockPending:1;
struct inode vfs_inode;
};
static inline struct cifsInodeInfo *
CIFS_I(struct inode *inode)
{
return container_of(inode, struct cifsInodeInfo, vfs_inode);
}
static inline struct cifs_sb_info *
CIFS_SB(struct super_block *sb)
{
return sb->s_fs_info;
}
static inline char CIFS_DIR_SEP(const struct cifs_sb_info *cifs_sb)
{
if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_POSIX_PATHS)
return '/';
else
return '\\';
}
#ifdef CONFIG_CIFS_STATS
#define cifs_stats_inc atomic_inc
static inline void cifs_stats_bytes_written(struct cifsTconInfo *tcon,
unsigned int bytes)
{
if (bytes) {
spin_lock(&tcon->stat_lock);
tcon->bytes_written += bytes;
spin_unlock(&tcon->stat_lock);
}
}
static inline void cifs_stats_bytes_read(struct cifsTconInfo *tcon,
unsigned int bytes)
{
spin_lock(&tcon->stat_lock);
tcon->bytes_read += bytes;
spin_unlock(&tcon->stat_lock);
}
#else
#define cifs_stats_inc(field) do {} while (0)
#define cifs_stats_bytes_written(tcon, bytes) do {} while (0)
#define cifs_stats_bytes_read(tcon, bytes) do {} while (0)
#endif
/* one of these for every pending CIFS request to the server */
struct mid_q_entry {
struct list_head qhead; /* mids waiting on reply from this server */
__u16 mid; /* multiplex id */
__u16 pid; /* process id */
__u32 sequence_number; /* for CIFS signing */
unsigned long when_alloc; /* when mid was created */
#ifdef CONFIG_CIFS_STATS2
unsigned long when_sent; /* time when smb send finished */
unsigned long when_received; /* when demux complete (taken off wire) */
#endif
struct cifsSesInfo *ses; /* smb was sent to this server */
struct task_struct *tsk; /* task waiting for response */
struct smb_hdr *resp_buf; /* response buffer */
int midState; /* wish this were enum but can not pass to wait_event */
__u8 command; /* smb command code */
bool largeBuf:1; /* if valid response, is pointer to large buf */
bool multiRsp:1; /* multiple trans2 responses for one request */
bool multiEnd:1; /* both received */
};
struct oplock_q_entry {
struct list_head qhead;
struct inode *pinode;
struct cifsTconInfo *tcon;
__u16 netfid;
};
/* for pending dnotify requests */
struct dir_notify_req {
struct list_head lhead;
__le16 Pid;
__le16 PidHigh;
__u16 Mid;
__u16 Tid;
__u16 Uid;
__u16 netfid;
__u32 filter; /* CompletionFilter (for multishot) */
int multishot;
struct file *pfile;
};
struct dfs_info3_param {
int flags; /* DFSREF_REFERRAL_SERVER, DFSREF_STORAGE_SERVER*/
int path_consumed;
int server_type;
int ref_flag;
char *path_name;
char *node_name;
};
static inline void free_dfs_info_param(struct dfs_info3_param *param)
{
if (param) {
kfree(param->path_name);
kfree(param->node_name);
kfree(param);
}
}
static inline void free_dfs_info_array(struct dfs_info3_param *param,
int number_of_items)
{
int i;
if ((number_of_items == 0) || (param == NULL))
return;
for (i = 0; i < number_of_items; i++) {
kfree(param[i].path_name);
kfree(param[i].node_name);
}
kfree(param);
}
#define MID_FREE 0
#define MID_REQUEST_ALLOCATED 1
#define MID_REQUEST_SUBMITTED 2
#define MID_RESPONSE_RECEIVED 4
#define MID_RETRY_NEEDED 8 /* session closed while this request out */
#define MID_NO_RESP_NEEDED 0x10
/* Types of response buffer returned from SendReceive2 */
#define CIFS_NO_BUFFER 0 /* Response buffer not returned */
#define CIFS_SMALL_BUFFER 1
#define CIFS_LARGE_BUFFER 2
#define CIFS_IOVEC 4 /* array of response buffers */
/* Type of Request to SendReceive2 */
#define CIFS_STD_OP 0 /* normal request timeout */
#define CIFS_LONG_OP 1 /* long op (up to 45 sec, oplock time) */
#define CIFS_VLONG_OP 2 /* sloow op - can take up to 180 seconds */
#define CIFS_BLOCKING_OP 4 /* operation can block */
#define CIFS_ASYNC_OP 8 /* do not wait for response */
#define CIFS_TIMEOUT_MASK 0x00F /* only one of 5 above set in req */
#define CIFS_LOG_ERROR 0x010 /* log NT STATUS if non-zero */
#define CIFS_LARGE_BUF_OP 0x020 /* large request buffer */
#define CIFS_NO_RESP 0x040 /* no response buffer required */
/* Security Flags: indicate type of session setup needed */
#define CIFSSEC_MAY_SIGN 0x00001
#define CIFSSEC_MAY_NTLM 0x00002
#define CIFSSEC_MAY_NTLMV2 0x00004
#define CIFSSEC_MAY_KRB5 0x00008
#ifdef CONFIG_CIFS_WEAK_PW_HASH
#define CIFSSEC_MAY_LANMAN 0x00010
#define CIFSSEC_MAY_PLNTXT 0x00020
#else
#define CIFSSEC_MAY_LANMAN 0
#define CIFSSEC_MAY_PLNTXT 0
#endif /* weak passwords */
#define CIFSSEC_MAY_SEAL 0x00040 /* not supported yet */
#define CIFSSEC_MUST_SIGN 0x01001
/* note that only one of the following can be set so the
result of setting MUST flags more than once will be to
require use of the stronger protocol */
#define CIFSSEC_MUST_NTLM 0x02002
#define CIFSSEC_MUST_NTLMV2 0x04004
#define CIFSSEC_MUST_KRB5 0x08008
#ifdef CONFIG_CIFS_WEAK_PW_HASH
#define CIFSSEC_MUST_LANMAN 0x10010
#define CIFSSEC_MUST_PLNTXT 0x20020
#ifdef CONFIG_CIFS_UPCALL
#define CIFSSEC_MASK 0x3F03F /* allows weak security but also krb5 */
#else
#define CIFSSEC_MASK 0x37037 /* current flags supported if weak */
#endif /* UPCALL */
#else /* do not allow weak pw hash */
#ifdef CONFIG_CIFS_UPCALL
#define CIFSSEC_MASK 0x0F00F /* flags supported if no weak allowed */
#else
#define CIFSSEC_MASK 0x07007 /* flags supported if no weak allowed */
#endif /* UPCALL */
#endif /* WEAK_PW_HASH */
#define CIFSSEC_MUST_SEAL 0x40040 /* not supported yet */
#define CIFSSEC_DEF (CIFSSEC_MAY_SIGN | CIFSSEC_MAY_NTLM | CIFSSEC_MAY_NTLMV2)
#define CIFSSEC_MAX (CIFSSEC_MUST_SIGN | CIFSSEC_MUST_NTLMV2)
#define CIFSSEC_AUTH_MASK (CIFSSEC_MAY_NTLM | CIFSSEC_MAY_NTLMV2 | CIFSSEC_MAY_LANMAN | CIFSSEC_MAY_PLNTXT | CIFSSEC_MAY_KRB5)
/*
*****************************************************************
* All constants go here
*****************************************************************
*/
#define UID_HASH (16)
/*
* Note that ONE module should define _DECLARE_GLOBALS_HERE to cause the
* following to be declared.
*/
/****************************************************************************
* Locking notes. All updates to global variables and lists should be
* protected by spinlocks or semaphores.
*
* Spinlocks
* ---------
* GlobalMid_Lock protects:
* list operations on pending_mid_q and oplockQ
* updates to XID counters, multiplex id and SMB sequence numbers
* GlobalSMBSesLock protects:
* list operations on tcp and SMB session lists and tCon lists
* f_owner.lock protects certain per file struct operations
* mapping->page_lock protects certain per page operations
*
* Semaphores
* ----------
* sesSem operations on smb session
* tconSem operations on tree connection
* fh_sem file handle reconnection operations
*
****************************************************************************/
#ifdef DECLARE_GLOBALS_HERE
#define GLOBAL_EXTERN
#else
#define GLOBAL_EXTERN extern
#endif
/*
* The list of servers that did not respond with NT LM 0.12.
* This list helps improve performance and eliminate the messages indicating
* that we had a communications error talking to the server in this list.
*/
/* Feature not supported */
/* GLOBAL_EXTERN struct servers_not_supported *NotSuppList; */
/*
* The following is a hash table of all the users we know about.
*/
GLOBAL_EXTERN struct smbUidInfo *GlobalUidList[UID_HASH];
/* GLOBAL_EXTERN struct list_head GlobalServerList; BB not implemented yet */
GLOBAL_EXTERN struct list_head GlobalSMBSessionList;
GLOBAL_EXTERN struct list_head GlobalTreeConnectionList;
GLOBAL_EXTERN rwlock_t GlobalSMBSeslock; /* protects list inserts on 3 above */
GLOBAL_EXTERN struct list_head GlobalOplock_Q;
/* Outstanding dir notify requests */
GLOBAL_EXTERN struct list_head GlobalDnotifyReqList;
/* DirNotify response queue */
GLOBAL_EXTERN struct list_head GlobalDnotifyRsp_Q;
/*
* Global transaction id (XID) information
*/
GLOBAL_EXTERN unsigned int GlobalCurrentXid; /* protected by GlobalMid_Sem */
GLOBAL_EXTERN unsigned int GlobalTotalActiveXid; /* prot by GlobalMid_Sem */
GLOBAL_EXTERN unsigned int GlobalMaxActiveXid; /* prot by GlobalMid_Sem */
GLOBAL_EXTERN spinlock_t GlobalMid_Lock; /* protects above & list operations */
/* on midQ entries */
GLOBAL_EXTERN char Local_System_Name[15];
/*
* Global counters, updated atomically
*/
GLOBAL_EXTERN atomic_t sesInfoAllocCount;
GLOBAL_EXTERN atomic_t tconInfoAllocCount;
GLOBAL_EXTERN atomic_t tcpSesAllocCount;
GLOBAL_EXTERN atomic_t tcpSesReconnectCount;
GLOBAL_EXTERN atomic_t tconInfoReconnectCount;
/* Various Debug counters */
GLOBAL_EXTERN atomic_t bufAllocCount; /* current number allocated */
#ifdef CONFIG_CIFS_STATS2
GLOBAL_EXTERN atomic_t totBufAllocCount; /* total allocated over all time */
GLOBAL_EXTERN atomic_t totSmBufAllocCount;
#endif
GLOBAL_EXTERN atomic_t smBufAllocCount;
GLOBAL_EXTERN atomic_t midCount;
/* Misc globals */
GLOBAL_EXTERN unsigned int multiuser_mount; /* if enabled allows new sessions
to be established on existing mount if we
have the uid/password or Kerberos credential
or equivalent for current user */
GLOBAL_EXTERN unsigned int oplockEnabled;
GLOBAL_EXTERN unsigned int experimEnabled;
GLOBAL_EXTERN unsigned int lookupCacheEnabled;
GLOBAL_EXTERN unsigned int extended_security; /* if on, session setup sent
with more secure ntlmssp2 challenge/resp */
GLOBAL_EXTERN unsigned int sign_CIFS_PDUs; /* enable smb packet signing */
GLOBAL_EXTERN unsigned int linuxExtEnabled;/*enable Linux/Unix CIFS extensions*/
GLOBAL_EXTERN unsigned int CIFSMaxBufSize; /* max size not including hdr */
GLOBAL_EXTERN unsigned int cifs_min_rcv; /* min size of big ntwrk buf pool */
GLOBAL_EXTERN unsigned int cifs_min_small; /* min size of small buf pool */
GLOBAL_EXTERN unsigned int cifs_max_pending; /* MAX requests at once to server*/