This helps in more control over debugging.
root@qemu-img-64:~# ls /pass/123
ls: cannot access /pass/123: No such file or directory
root@qemu-img-64:~# cat /sys/kernel/debug/tracing/trace
# tracer: nop
#
#           TASK-PID    CPU#    TIMESTAMP  FUNCTION
#              | |       |          |         |
              ls-1536  [001]    70.928584: 9p_protocol_dump: clnt 18446612132784021504 P9_TWALK(tag = 1)
000: 16 00 00 00 6e 01 00 01 00 00 00 02 00 00 00 01
010: 00 03 00 31 32 33 00 00 00 ff ff ff ff 00 00 00
              ls-1536  [001]    70.928587: <stack trace>
 => trace_9p_protocol_dump
 => p9pdu_finalize
 => p9_client_rpc
 => p9_client_walk
 => v9fs_vfs_lookup
 => d_alloc_and_lookup
 => walk_component
 => path_lookupat
              ls-1536  [000]    70.929696: 9p_protocol_dump: clnt 18446612132784021504 P9_RLERROR(tag = 1)
000: 0b 00 00 00 07 01 00 02 00 00 00 4e 03 00 02 00
010: 00 00 00 00 03 00 02 00 00 00 00 00 ff 43 00 00
              ls-1536  [000]    70.929697: <stack trace>
 => trace_9p_protocol_dump
 => p9_client_rpc
 => p9_client_walk
 => v9fs_vfs_lookup
 => d_alloc_and_lookup
 => walk_component
 => path_lookupat
 => do_path_lookup
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
		
	
			
		
			
				
	
	
		
			271 lines
		
	
	
	
		
			9 KiB
			
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			271 lines
		
	
	
	
		
			9 KiB
			
		
	
	
	
		
			C
		
	
	
	
	
	
| /*
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|  * include/net/9p/client.h
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|  *
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|  * 9P Client Definitions
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|  *
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|  *  Copyright (C) 2008 by Eric Van Hensbergen <ericvh@gmail.com>
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|  *  Copyright (C) 2007 by Latchesar Ionkov <lucho@ionkov.net>
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|  *
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|  *  This program is free software; you can redistribute it and/or modify
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|  *  it under the terms of the GNU General Public License version 2
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|  *  as published by the Free Software Foundation.
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|  *
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|  *  This program is distributed in the hope that it will be useful,
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|  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
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|  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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|  *  GNU General Public License for more details.
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|  *
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|  *  You should have received a copy of the GNU General Public License
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|  *  along with this program; if not, write to:
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|  *  Free Software Foundation
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|  *  51 Franklin Street, Fifth Floor
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|  *  Boston, MA  02111-1301  USA
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|  *
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|  */
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| 
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| #ifndef NET_9P_CLIENT_H
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| #define NET_9P_CLIENT_H
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| 
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| /* Number of requests per row */
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| #define P9_ROW_MAXTAG 255
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| 
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| /** enum p9_proto_versions - 9P protocol versions
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|  * @p9_proto_legacy: 9P Legacy mode, pre-9P2000.u
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|  * @p9_proto_2000u: 9P2000.u extension
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|  * @p9_proto_2000L: 9P2000.L extension
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|  */
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| 
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| enum p9_proto_versions{
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| 	p9_proto_legacy,
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| 	p9_proto_2000u,
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| 	p9_proto_2000L,
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| };
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| 
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| 
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| /**
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|  * enum p9_trans_status - different states of underlying transports
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|  * @Connected: transport is connected and healthy
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|  * @Disconnected: transport has been disconnected
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|  * @Hung: transport is connected by wedged
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|  *
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|  * This enumeration details the various states a transport
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|  * instatiation can be in.
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|  */
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| 
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| enum p9_trans_status {
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| 	Connected,
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| 	BeginDisconnect,
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| 	Disconnected,
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| 	Hung,
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| };
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| 
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| /**
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|  * enum p9_req_status_t - status of a request
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|  * @REQ_STATUS_IDLE: request slot unused
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|  * @REQ_STATUS_ALLOC: request has been allocated but not sent
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|  * @REQ_STATUS_UNSENT: request waiting to be sent
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|  * @REQ_STATUS_SENT: request sent to server
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|  * @REQ_STATUS_FLSH: a flush has been sent for this request
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|  * @REQ_STATUS_RCVD: response received from server
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|  * @REQ_STATUS_FLSHD: request has been flushed
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|  * @REQ_STATUS_ERROR: request encountered an error on the client side
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|  *
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|  * The @REQ_STATUS_IDLE state is used to mark a request slot as unused
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|  * but use is actually tracked by the idpool structure which handles tag
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|  * id allocation.
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|  *
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|  */
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| 
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| enum p9_req_status_t {
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| 	REQ_STATUS_IDLE,
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| 	REQ_STATUS_ALLOC,
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| 	REQ_STATUS_UNSENT,
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| 	REQ_STATUS_SENT,
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| 	REQ_STATUS_FLSH,
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| 	REQ_STATUS_RCVD,
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| 	REQ_STATUS_FLSHD,
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| 	REQ_STATUS_ERROR,
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| };
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| 
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| /**
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|  * struct p9_req_t - request slots
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|  * @status: status of this request slot
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|  * @t_err: transport error
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|  * @flush_tag: tag of request being flushed (for flush requests)
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|  * @wq: wait_queue for the client to block on for this request
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|  * @tc: the request fcall structure
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|  * @rc: the response fcall structure
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|  * @aux: transport specific data (provided for trans_fd migration)
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|  * @req_list: link for higher level objects to chain requests
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|  *
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|  * Transport use an array to track outstanding requests
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|  * instead of a list.  While this may incurr overhead during initial
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|  * allocation or expansion, it makes request lookup much easier as the
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|  * tag id is a index into an array.  (We use tag+1 so that we can accommodate
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|  * the -1 tag for the T_VERSION request).
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|  * This also has the nice effect of only having to allocate wait_queues
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|  * once, instead of constantly allocating and freeing them.  Its possible
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|  * other resources could benefit from this scheme as well.
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|  *
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|  */
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| 
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| struct p9_req_t {
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| 	int status;
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| 	int t_err;
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| 	wait_queue_head_t *wq;
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| 	struct p9_fcall *tc;
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| 	struct p9_fcall *rc;
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| 	void *aux;
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| 
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| 	struct list_head req_list;
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| };
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| 
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| /**
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|  * struct p9_client - per client instance state
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|  * @lock: protect @fidlist
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|  * @msize: maximum data size negotiated by protocol
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|  * @dotu: extension flags negotiated by protocol
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|  * @proto_version: 9P protocol version to use
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|  * @trans_mod: module API instantiated with this client
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|  * @trans: tranport instance state and API
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|  * @conn: connection state information used by trans_fd
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|  * @fidpool: fid handle accounting for session
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|  * @fidlist: List of active fid handles
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|  * @tagpool - transaction id accounting for session
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|  * @reqs - 2D array of requests
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|  * @max_tag - current maximum tag id allocated
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|  *
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|  * The client structure is used to keep track of various per-client
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|  * state that has been instantiated.
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|  * In order to minimize per-transaction overhead we use a
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|  * simple array to lookup requests instead of a hash table
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|  * or linked list.  In order to support larger number of
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|  * transactions, we make this a 2D array, allocating new rows
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|  * when we need to grow the total number of the transactions.
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|  *
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|  * Each row is 256 requests and we'll support up to 256 rows for
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|  * a total of 64k concurrent requests per session.
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|  *
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|  * Bugs: duplicated data and potentially unnecessary elements.
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|  */
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| 
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| struct p9_client {
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| 	spinlock_t lock; /* protect client structure */
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| 	unsigned int msize;
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| 	unsigned char proto_version;
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| 	struct p9_trans_module *trans_mod;
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| 	enum p9_trans_status status;
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| 	void *trans;
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| 	struct p9_conn *conn;
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| 
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| 	struct p9_idpool *fidpool;
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| 	struct list_head fidlist;
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| 
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| 	struct p9_idpool *tagpool;
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| 	struct p9_req_t *reqs[P9_ROW_MAXTAG];
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| 	int max_tag;
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| };
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| 
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| /**
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|  * struct p9_fid - file system entity handle
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|  * @clnt: back pointer to instantiating &p9_client
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|  * @fid: numeric identifier for this handle
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|  * @mode: current mode of this fid (enum?)
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|  * @qid: the &p9_qid server identifier this handle points to
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|  * @iounit: the server reported maximum transaction size for this file
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|  * @uid: the numeric uid of the local user who owns this handle
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|  * @rdir: readdir accounting structure (allocated on demand)
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|  * @flist: per-client-instance fid tracking
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|  * @dlist: per-dentry fid tracking
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|  *
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|  * TODO: This needs lots of explanation.
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|  */
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| 
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| struct p9_fid {
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| 	struct p9_client *clnt;
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| 	u32 fid;
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| 	int mode;
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| 	struct p9_qid qid;
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| 	u32 iounit;
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| 	uid_t uid;
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| 
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| 	void *rdir;
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| 
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| 	struct list_head flist;
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| 	struct list_head dlist;	/* list of all fids attached to a dentry */
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| };
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| 
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| /**
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|  * struct p9_dirent - directory entry structure
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|  * @qid: The p9 server qid for this dirent
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|  * @d_off: offset to the next dirent
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|  * @d_type: type of file
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|  * @d_name: file name
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|  */
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| 
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| struct p9_dirent {
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| 	struct p9_qid qid;
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| 	u64 d_off;
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| 	unsigned char d_type;
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| 	char d_name[256];
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| };
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| 
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| int p9_client_statfs(struct p9_fid *fid, struct p9_rstatfs *sb);
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| int p9_client_rename(struct p9_fid *fid, struct p9_fid *newdirfid,
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| 		     const char *name);
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| int p9_client_renameat(struct p9_fid *olddirfid, const char *old_name,
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| 		       struct p9_fid *newdirfid, const char *new_name);
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| struct p9_client *p9_client_create(const char *dev_name, char *options);
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| void p9_client_destroy(struct p9_client *clnt);
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| void p9_client_disconnect(struct p9_client *clnt);
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| void p9_client_begin_disconnect(struct p9_client *clnt);
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| struct p9_fid *p9_client_attach(struct p9_client *clnt, struct p9_fid *afid,
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| 					char *uname, u32 n_uname, char *aname);
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| struct p9_fid *p9_client_walk(struct p9_fid *oldfid, uint16_t nwname,
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| 		char **wnames, int clone);
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| int p9_client_open(struct p9_fid *fid, int mode);
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| int p9_client_fcreate(struct p9_fid *fid, char *name, u32 perm, int mode,
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| 							char *extension);
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| int p9_client_link(struct p9_fid *fid, struct p9_fid *oldfid, char *newname);
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| int p9_client_symlink(struct p9_fid *fid, char *name, char *symname, gid_t gid,
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| 							struct p9_qid *qid);
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| int p9_client_create_dotl(struct p9_fid *ofid, char *name, u32 flags, u32 mode,
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| 		gid_t gid, struct p9_qid *qid);
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| int p9_client_clunk(struct p9_fid *fid);
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| int p9_client_fsync(struct p9_fid *fid, int datasync);
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| int p9_client_remove(struct p9_fid *fid);
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| int p9_client_unlinkat(struct p9_fid *dfid, const char *name, int flags);
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| int p9_client_read(struct p9_fid *fid, char *data, char __user *udata,
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| 							u64 offset, u32 count);
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| int p9_client_write(struct p9_fid *fid, char *data, const char __user *udata,
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| 							u64 offset, u32 count);
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| int p9_client_readdir(struct p9_fid *fid, char *data, u32 count, u64 offset);
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| int p9dirent_read(struct p9_client *clnt, char *buf, int len,
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| 		  struct p9_dirent *dirent);
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| struct p9_wstat *p9_client_stat(struct p9_fid *fid);
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| int p9_client_wstat(struct p9_fid *fid, struct p9_wstat *wst);
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| int p9_client_setattr(struct p9_fid *fid, struct p9_iattr_dotl *attr);
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| 
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| struct p9_stat_dotl *p9_client_getattr_dotl(struct p9_fid *fid,
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| 							u64 request_mask);
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| 
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| int p9_client_mknod_dotl(struct p9_fid *oldfid, char *name, int mode,
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| 			dev_t rdev, gid_t gid, struct p9_qid *);
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| int p9_client_mkdir_dotl(struct p9_fid *fid, char *name, int mode,
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| 				gid_t gid, struct p9_qid *);
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| int p9_client_lock_dotl(struct p9_fid *fid, struct p9_flock *flock, u8 *status);
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| int p9_client_getlock_dotl(struct p9_fid *fid, struct p9_getlock *fl);
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| struct p9_req_t *p9_tag_lookup(struct p9_client *, u16);
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| void p9_client_cb(struct p9_client *c, struct p9_req_t *req);
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| 
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| int p9_parse_header(struct p9_fcall *, int32_t *, int8_t *, int16_t *, int);
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| int p9stat_read(struct p9_client *, char *, int, struct p9_wstat *);
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| void p9stat_free(struct p9_wstat *);
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| 
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| int p9_is_proto_dotu(struct p9_client *clnt);
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| int p9_is_proto_dotl(struct p9_client *clnt);
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| struct p9_fid *p9_client_xattrwalk(struct p9_fid *, const char *, u64 *);
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| int p9_client_xattrcreate(struct p9_fid *, const char *, u64, int);
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| int p9_client_readlink(struct p9_fid *fid, char **target);
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| 
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| #endif /* NET_9P_CLIENT_H */
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