WebSVN – HelenOS – Diff – /trunk/uspace/srv/vfs/vfs_ops.c

  * This rwlock prevents the race between a triplet-to-VFS-node resolution and a
  * concurrent VFS operation which modifies the file system namespace.
  */
 RWLOCK_INITIALIZE(namespace_rwlock);
-futex_t rootfs_futex = FUTEX_INITIALIZER;
 vfs_pair_t rootfs = {
     .fs_handle = 0,
     .dev_handle = 0
 };
     ipcarg_t rc;
     int phone;
     aid_t msg;
     ipc_call_t answer;
     /* Resolve the path to the mountpoint. */
-    futex_down(&rootfs_futex);
+    rwlock_write_lock(&namespace_rwlock);
     if (rootfs.fs_handle) {
         /* We already have the root FS. */
-        rwlock_write_lock(&namespace_rwlock);
         if (str_cmp(mp, "/") == 0) {
             /* Trying to mount root FS over root FS */
-            rwlock_write_unlock(&namespace_rwlock);
-            futex_up(&rootfs_futex);
             ipc_answer_0(rid, EBUSY);
+            rwlock_write_unlock(&namespace_rwlock);
             return;
+        }
         rc = vfs_lookup_internal(mp, L_DIRECTORY, &mp_res, NULL);
         if (rc != EOK) {
             /* The lookup failed for some reason. */
-            rwlock_write_unlock(&namespace_rwlock);
-            futex_up(&rootfs_futex);
             ipc_answer_0(rid, rc);
+            rwlock_write_unlock(&namespace_rwlock);
             return;
+        }
         mp_node = vfs_node_get(&mp_res);
         if (!mp_node) {
-            rwlock_write_unlock(&namespace_rwlock);
-            futex_up(&rootfs_futex);
             ipc_answer_0(rid, ENOMEM);
+            rwlock_write_unlock(&namespace_rwlock);
             return;
+        }
         /*
          * Now we hold a reference to mp_node.
          * It will be dropped upon the corresponding VFS_UNMOUNT.
          * This prevents the mount point from being deleted.
          */
-        rwlock_write_unlock(&namespace_rwlock);
     } else {
         /* We still don't have the root file system mounted. */
         if (str_cmp(mp, "/") == 0) {
             /*
              * For this simple, but important case,
             rc = ipc_data_write_start(phone, (void *)opts,
                 str_size(opts));
             if (rc != EOK) {
                 async_wait_for(msg, NULL);
                 vfs_release_phone(phone);
-                futex_up(&rootfs_futex);
                 ipc_answer_0(rid, rc);
+                rwlock_write_unlock(&namespace_rwlock);
                 return;
+            }
             async_wait_for(msg, &rc);
             vfs_release_phone(phone);
             if (rc != EOK) {
-                futex_up(&rootfs_futex);
                 ipc_answer_0(rid, rc);
+                rwlock_write_unlock(&namespace_rwlock);
                 return;
+            }
             rindex = (fs_index_t) IPC_GET_ARG1(answer);
             rsize = (size_t) IPC_GET_ARG2(answer);
             mr_res.lnkcnt = rlnkcnt;
             mr_res.type = VFS_NODE_DIRECTORY;
             rootfs.fs_handle = fs_handle;
             rootfs.dev_handle = dev_handle;
-            futex_up(&rootfs_futex);
             /* Add reference to the mounted root. */
             mr_node = vfs_node_get(&mr_res);
             assert(mr_node);
             ipc_answer_0(rid, rc);
+            rwlock_write_unlock(&namespace_rwlock);
             return;
         } else {
             /*
              * We can't resolve this without the root filesystem
              * being mounted first.
              */
-            futex_up(&rootfs_futex);
             ipc_answer_0(rid, ENOENT);
+            rwlock_write_unlock(&namespace_rwlock);
             return;
+        }
+    }
-    futex_up(&rootfs_futex);
     /*
      * At this point, we have all necessary pieces: file system and device
      * handles, and we know the mount point VFS node.
      */
         vfs_release_phone(phone);
         /* Mount failed, drop reference to mp_node. */
         if (mp_node)
             vfs_node_put(mp_node);
         ipc_answer_0(rid, rc);
+        rwlock_write_unlock(&namespace_rwlock);
         return;
+    }
     /* send the mount options */
     rc = ipc_data_write_start(phone, (void *)opts, str_size(opts));
         vfs_release_phone(phone);
         /* Mount failed, drop reference to mp_node. */
         if (mp_node)
             vfs_node_put(mp_node);
         ipc_answer_0(rid, rc);
+        rwlock_write_unlock(&namespace_rwlock);
         return;
+    }
     async_wait_for(msg, &rc);
     vfs_release_phone(phone);
-    if (rc != EOK) {
+    if (rc == EOK) {
+        rindex = (fs_index_t) IPC_GET_ARG1(answer);
+        rsize = (size_t) IPC_GET_ARG2(answer);
+        rlnkcnt = (unsigned) IPC_GET_ARG3(answer);
+        mr_res.triplet.fs_handle = fs_handle;
+        mr_res.triplet.dev_handle = dev_handle;
+        mr_res.triplet.index = rindex;
+        mr_res.size = rsize;
+        mr_res.lnkcnt = rlnkcnt;
+        mr_res.type = VFS_NODE_DIRECTORY;
+        /* Add reference to the mounted root. */
+        mr_node = vfs_node_get(&mr_res);
+        assert(mr_node);
+    } else {
         /* Mount failed, drop reference to mp_node. */
         if (mp_node)
             vfs_node_put(mp_node);
+    }
-    rindex = (fs_index_t) IPC_GET_ARG1(answer);
-    rsize = (size_t) IPC_GET_ARG2(answer);
-    rlnkcnt = (unsigned) IPC_GET_ARG3(answer);
-    mr_res.triplet.fs_handle = fs_handle;
-    mr_res.triplet.dev_handle = dev_handle;
-    mr_res.triplet.index = rindex;
-    mr_res.size = rsize;
-    mr_res.lnkcnt = rlnkcnt;
-    mr_res.type = VFS_NODE_DIRECTORY;
-    /* Add reference to the mounted root. */
-    mr_node = vfs_node_get(&mr_res);
-    assert(mr_node);
     ipc_answer_0(rid, rc);
+    rwlock_write_unlock(&namespace_rwlock);
+}
 /** Process pending mount requests */
 void vfs_process_pending_mount()
+{

Subversion Repositories HelenOS

(root)/trunk/uspace/srv/vfs/vfs_ops.c – Rev 4427 → 4431