/* * 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 RFC1001_NAME_LEN 15 #define RFC1001_NAME_LEN_WITH_NULL (RFC1001_NAME_LEN + 1) /* currently length of NIP6_FMT */ #define SERVER_NAME_LENGTH 40 #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, NTLMv2 hash */ NTLMSSP, /* NTLMSSP via SPNEGO, NTLMv2 hash */ Kerberos, /* Kerberos via SPNEGO */ MSKerberos, /* MS Kerberos via SPNEGO */ }; enum protocolEnum { TCP = 0, 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 { struct list_head tcp_ses_list; struct list_head smb_ses_list; int srv_count; /* reference counter */ /* 15 character server name + 0x20 16th byte indicating type = srv */ char server_RFC1001_name[RFC1001_NAME_LEN_WITH_NULL]; 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 */ bool noblocksnd; /* use blocking sendmsg */ bool noautotune; /* do not autotune send buf sizes */ 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 mutex srv_mutex; 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 max_rw; /* maxRw specifies the maximum */ /* message size the server can send or receive for */ /* SMB_COM_WRITE_RAW or SMB_COM_READ_RAW. */ unsigned int max_vcs; /* maximum number of smb sessions, at least those that can be specified uniquely with vcnumbers */ 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[RFC1001_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 smb_ses_list; struct list_head tcon_list; struct semaphore sesSem; #if 0 struct cifsUidInfo *uidInfo; /* pointer to user info */ #endif struct TCP_Server_Info *server; /* pointer to server info */ int ses_count; /* reference counter */ enum statusEnum status; unsigned overrideSecFlg; /* if non-zero override global sec flags */ __u16 ipc_tid; /* special tid for connection to IPC share */ __u16 flags; __u16 vcnum; 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; bool need_reconnect:1; /* connection reset, uid now invalid */ }; /* 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 tcon_list; int tc_count; struct list_head openFileList; struct cifsSesInfo *ses; /* pointer to session associated with */ char treeName[MAX_TREE_SIZE + 1]; /* UNC name of resource in ASCII */ char *nativeFileSystem; char *password; /* for share-level security */ __u16 tid; /* The 2 byte tree id */ __u16 Flags; /* optional support bits */ enum statusEnum tidStatus; #ifdef CONFIG_CIFS_STATS atomic_t num_smbs_sent; atomic_t num_writes; atomic_t num_reads; atomic_t num_flushes; 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 */ bool local_lease:1; /* check leases (only) on local system not remote */ bool broken_posix_open; /* e.g. Samba server versions < 3.3.2, 3.2.9 */ bool need_reconnect:1; /* connection reset, tid now invalid */ /* 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 *last_entry; 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 mutex fh_mutex; /* 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; bool delete_pending:1; /* DELETE_ON_CLOSE is set */ u64 server_eof; /* current file size on server */ 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 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_MAY_NTLMSSP 0x00080 /* raw ntlmssp with ntlmv2 */ #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 0xAF0AF /* allows weak security but also krb5 */ #else #define CIFSSEC_MASK 0xA70A7 /* current flags supported if weak */ #endif /* UPCALL */ #else /* do not allow weak pw hash */ #ifdef CONFIG_CIFS_UPCALL #define CIFSSEC_MASK 0x8F08F /* flags supported if no weak allowed */ #else #define CIFSSEC_MASK 0x87087 /* flags supported if no weak allowed */ #endif /* UPCALL */ #endif /* WEAK_PW_HASH */ #define CIFSSEC_MUST_SEAL 0x40040 /* not supported yet */ #define CIFSSEC_MUST_NTLMSSP 0x80080 /* raw ntlmssp with ntlmv2 */ #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 | CIFSSEC_MAY_NTLMSSP) /* ***************************************************************** * 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 TCP_Server_Info structures, ie each of the sockets * connecting our client to a distinct server (ip address), is * chained together by cifs_tcp_ses_list. The list of all our SMB * sessions (and from that the tree connections) can be found * by iterating over cifs_tcp_ses_list */ GLOBAL_EXTERN struct list_head cifs_tcp_ses_list; /* * This lock protects the cifs_tcp_ses_list, the list of smb sessions per * tcp session, and the list of tcon's per smb session. It also protects * the reference counters for the server, smb session, and tcon. Finally, * changes to the tcon->tidStatus should be done while holding this lock. */ GLOBAL_EXTERN rwlock_t cifs_tcp_ses_lock; /* * This lock protects the cifs_file->llist and cifs_file->flist * list operations, and updates to some flags (cifs_file->invalidHandle) * It will be moved to either use the tcon->stat_lock or equivalent later. * If cifs_tcp_ses_lock and the lock below are both needed to be held, then * the cifs_tcp_ses_lock must be grabbed first and released last. */ GLOBAL_EXTERN rwlock_t GlobalSMBSeslock; 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*/