[virto-9p] Implement TLOCK

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(1) - Blocked lock request, if there is a
            conflicting lock exists, wait for that lock to be released.
          P9_LOCK_FLAGS_RECLAIM(2) - 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>

1 files changed, 30 insertions, 0 deletions

diff --git a/hw/virtio-9p.h b/hw/virtio-9p.h
index 0816ad66ec..4555f39752 100644
--- a/hw/virtio-9p.h
+++ b/hw/virtio-9p.h
@@ -37,6 +37,8 @@ enum {
     P9_RXATTRCREATE,
     P9_TREADDIR = 40,
     P9_RREADDIR,
+    P9_TLOCK = 52,
+    P9_RLOCK,
     P9_TLINK = 70,
     P9_RLINK,
     P9_TMKDIR = 72,
@@ -434,6 +436,34 @@ typedef struct V9fsXattrState
     void *value;
 } V9fsXattrState;
 
+#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
+
+typedef struct V9fsFlock
+{
+    uint8_t type;
+    uint32_t flags;
+    uint64_t start; /* absolute offset */
+    uint64_t length;
+    uint32_t proc_id;
+    V9fsString client_id;
+} V9fsFlock;
+
+typedef struct V9fsLockState
+{
+    V9fsPDU *pdu;
+    size_t offset;
+    int8_t status;
+    struct stat stbuf;
+    V9fsFidState *fidp;
+    V9fsFlock *flock;
+} V9fsLockState;
+
 extern size_t pdu_packunpack(void *addr, struct iovec *sg, int sg_count,
                             size_t offset, size_t size, int pack);