qemu-virtio9p: Implement TGETLOCK

Synopsis

    size[4] TGetlock tag[2] fid[4] getlock[n]
    size[4] RGetlock tag[2] getlock[n]

Description

TGetlock is used to test for the existence of byte range posix locks on
a file identified by given fid. The reply contains getlock structure. If
the lock could be placed it returns F_UNLCK in type field of getlock structure.
Otherwise it returns the details of the conflicting locks in the getlock
structure

    getlock structure:
      type[1] - Type of lock: F_RDLCK, F_WRLCK
      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
      proc_id[4] - process id that wants to take lock/owns the task
               in case of reply
      client[4] - Client id of the system that owns the process

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, 41 insertions, 0 deletions

diff --git a/hw/virtio-9p.c b/hw/virtio-9p.c
index 20acb5b..8ae233e 100644
--- a/hw/virtio-9p.c
+++ b/hw/virtio-9p.c
@@ -3203,6 +3203,46 @@ out:
     qemu_free(vs);
 }
 
+/*
+ * When a TGETLOCK request comes, always return success because all lock
+ * handling is done by client's VFS layer.
+ */
+
+static void v9fs_getlock(V9fsState *s, V9fsPDU *pdu)
+{
+    int32_t fid, err = 0;
+    V9fsGetlockState *vs;
+
+    vs = qemu_mallocz(sizeof(*vs));
+    vs->pdu = pdu;
+    vs->offset = 7;
+
+    vs->glock = qemu_malloc(sizeof(*vs->glock));
+    pdu_unmarshal(vs->pdu, vs->offset, "dbqqds", &fid, &vs->glock->type,
+                &vs->glock->start, &vs->glock->length, &vs->glock->proc_id,
+		&vs->glock->client_id);
+
+    vs->fidp = lookup_fid(s, fid);
+    if (vs->fidp == NULL) {
+        err = -ENOENT;
+        goto out;
+    }
+
+    err = v9fs_do_fstat(s, vs->fidp->fs.fd, &vs->stbuf);
+    if (err < 0) {
+        err = -errno;
+        goto out;
+    }
+    vs->glock->type = F_UNLCK;
+    vs->offset += pdu_marshal(vs->pdu, vs->offset, "bqqds", vs->glock->type,
+                vs->glock->start, vs->glock->length, vs->glock->proc_id,
+		&vs->glock->client_id);
+out:
+    complete_pdu(s, vs->pdu, err);
+    qemu_free(vs->glock);
+    qemu_free(vs);
+}
+
 static void v9fs_mkdir_post_lstat(V9fsState *s, V9fsMkState *vs, int err)
 {
     if (err == -1) {
@@ -3466,6 +3506,7 @@ static pdu_handler_t *pdu_handlers[] = {
     [P9_TMKNOD] = v9fs_mknod,
     [P9_TRENAME] = v9fs_rename,
     [P9_TLOCK] = v9fs_lock,
+    [P9_TGETLOCK] = v9fs_getlock,
     [P9_TMKDIR] = v9fs_mkdir,
     [P9_TVERSION] = v9fs_version,
     [P9_TLOPEN] = v9fs_open,