hw/9pfs: add 9P2000.L unlinkat operation

unlinkat - Remove a directory entry

size[4] Tunlinkat tag[2] dirfid[4] name[s] flag[4]
size[4] Runlinkat tag[2]

older Tremove have the below request format

size[4] Tremove tag[2] fid[4]

The remove message is used to remove a directory entry either file or directory
The remove opreation is actually a directory opertation and should ideally have
dirfid, if not we cannot represent the fid on server with anything other than
name. We will have to derive the directory name from fid in the Tremove request.

NOTE: The operation doesn't clunk the unlink fid.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

diff --git a/hw/9pfs/virtio-9p.c b/hw/9pfs/virtio-9p.c
index 0293fe42b106526e71f4a301b0d64f31b8bb5ba3..d28edb799a05a3d148013ba52f54bc06b02ddb64 100644 (file)
--- a/hw/9pfs/virtio-9p.c
+++ b/hw/9pfs/virtio-9p.c
@@ -2338,6 +2338,45 @@ out_nofid:
     complete_pdu(pdu->s, pdu, err);
 }
 
+static void v9fs_unlinkat(void *opaque)
+{
+    int err = 0;
+    V9fsString name;
+    int32_t dfid, flags;
+    size_t offset = 7;
+    V9fsFidState *dfidp;
+    V9fsPDU *pdu = opaque;
+    V9fsString full_name;
+
+    pdu_unmarshal(pdu, offset, "dsd", &dfid, &name, &flags);
+
+    dfidp = get_fid(pdu->s, dfid);
+    if (dfidp == NULL) {
+        err = -EINVAL;
+        goto out_nofid;
+    }
+    v9fs_string_init(&full_name);
+    v9fs_string_sprintf(&full_name, "%s/%s", dfidp->path.data, name.data);
+    /*
+     * IF the file is unlinked, we cannot reopen
+     * the file later. So don't reclaim fd
+     */
+    err = v9fs_mark_fids_unreclaim(pdu->s, &full_name);
+    if (err < 0) {
+        goto out_err;
+    }
+    err = v9fs_co_remove(pdu->s, &full_name);
+    if (!err) {
+        err = offset;
+    }
+out_err:
+    put_fid(pdu->s, dfidp);
+    v9fs_string_free(&full_name);
+out_nofid:
+    complete_pdu(pdu->s, pdu, err);
+    v9fs_string_free(&name);
+}
+
 static int v9fs_complete_rename(V9fsState *s, V9fsFidState *fidp,
                                 int32_t newdirfid, V9fsString *name)
 {
@@ -3040,6 +3079,7 @@ static CoroutineEntry *pdu_co_handlers[] = {
     [P9_TGETLOCK] = v9fs_getlock,
     [P9_TRENAMEAT] = v9fs_renameat,
     [P9_TREADLINK] = v9fs_readlink,
+    [P9_TUNLINKAT] = v9fs_unlinkat,
     [P9_TMKDIR] = v9fs_mkdir,
     [P9_TVERSION] = v9fs_version,
     [P9_TLOPEN] = v9fs_open,

diff --git a/hw/9pfs/virtio-9p.h b/hw/9pfs/virtio-9p.h
index 49507825b668c6376a2b3cff9ec53c07d9e0bfcb..17d44b41ca70693cdc8d1fc329295aeb643326c1 100644 (file)
--- a/hw/9pfs/virtio-9p.h
+++ b/hw/9pfs/virtio-9p.h
@@ -52,6 +52,8 @@ enum {
     P9_RMKDIR,
     P9_TRENAMEAT = 74,
     P9_RRENAMEAT,
+    P9_TUNLINKAT = 76,
+    P9_RUNLINKAT,
     P9_TVERSION = 100,
     P9_RVERSION,
     P9_TAUTH = 102,