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9p: Implement TLOCK

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Synopsis

    size[4] TLock tag[2] fid[4] flock[n]
    size[4] RLock tag[2] status[1]

Description

Tlock is used to acquire/release byte range posix locks on a file
identified by given fid. The reply contains status of the lock request

    flock structure:
        type[1] - Type of lock: F_RDLCK, F_WRLCK, F_UNLCK
        flags[4] - Flags could be either of
          P9_LOCK_FLAGS_BLOCK - Blocked lock request, if there is a
            conflicting lock exists, wait for that lock to be released.
          P9_LOCK_FLAGS_RECLAIM - Reclaim lock request, used when client is
            trying to reclaim a lock after a server restrart (due to crash)
        start[8] - Starting offset for lock
        length[8] - Number of bytes to lock
          If length is 0, lock all bytes starting at the location 'start'
          through to the end of file
        pid[4] - PID of the process that wants to take lock
        client_id[4] - Unique client id

        status[1] - Status of the lock request, can be
          P9_LOCK_SUCCESS(0), P9_LOCK_BLOCKED(1), P9_LOCK_ERROR(2) or
          P9_LOCK_GRACE(3)
          P9_LOCK_SUCCESS - Request was successful
          P9_LOCK_BLOCKED - A conflicting lock is held by another process
          P9_LOCK_ERROR - Error while processing the lock request
          P9_LOCK_GRACE - Server is in grace period, it can't accept new lock
            requests in this period (except locks with
            P9_LOCK_FLAGS_RECLAIM flag set)

Signed-off-by: M. Mohan Kumar <mohan@in.ibm.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Venkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
This commit is contained in:
M. Mohan Kumar
2010-09-27 11:34:24 +05:30
committed by Eric Van Hensbergen
parent 920e65dc69
commit a099027c77
5 changed files with 222 additions and 2 deletions
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28
include/net/9p/9p.h
View File

@ -165,6 +165,8 @@ enum p9_msg_t {
P9_RREADDIR,
P9_TFSYNC = 50,
P9_RFSYNC,
P9_TLOCK = 52,
P9_RLOCK,
P9_TLINK = 70,
P9_RLINK,
P9_TMKDIR = 72,
@ -464,6 +466,32 @@ struct p9_iattr_dotl {
u64 mtime_nsec;
};
#define P9_LOCK_SUCCESS 0
#define P9_LOCK_BLOCKED 1
#define P9_LOCK_ERROR 2
#define P9_LOCK_GRACE 3
#define P9_LOCK_FLAGS_BLOCK 1
#define P9_LOCK_FLAGS_RECLAIM 2
/* struct p9_flock: POSIX lock structure
* @type - type of lock
* @flags - lock flags
* @start - starting offset of the lock
* @length - number of bytes
* @proc_id - process id which wants to take lock
* @client_id - client id
*/
struct p9_flock {
u8 type;
u32 flags;
u64 start;
u64 length;
u32 proc_id;
char *client_id;
};
/* Structures for Protocol Operations */
struct p9_tstatfs {
u32 fid;