Changeset 0a201454 in mainline

Timestamp:

2019-10-07T11:21:27Z (5 years ago)

Author:

Jiri Svoboda <jiri@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

3106054

Parents:

5667dca

git-author:

Jiri Svoboda <jiri@…> (2019-10-06 11:19:48)

git-committer:

Jiri Svoboda <jiri@…> (2019-10-07 11:21:27)

Message:

Volsrv should not use zero as a valid reference count

Volume server allows the reference count for a valid volume with
persistent configuration to be zero, but refcnt did not expect that
and increasing refcount up from zero tripped assertion in the same_twice
test. The solution is to add one extra reference to persistent volumes
and have zero reference count always mean the volume can be freed.

File:

• uspace/srv/volsrv/volume.c (modified) (3 diffs)

uspace/srv/volsrv/volume.c

@@ -367 +367 @@
         if (refcount_down(&volume->refcnt)) {
                 /* No more references. Check if volume is persistent. */
-                if (!vol_volume_is_persist(volume)) {
-                        list_remove(&volume->lvolumes);
-                        vol_volume_delete(volume);
-                }
+                list_remove(&volume->lvolumes);
+                vol_volume_delete(volume);
         }
 }
@@ -399 +397 @@
                 /* Volume is now persistent */
                 if (volume->nvolume == NULL) {
+                        /* Prevent volume from being freed */
+                        refcount_up(&volume->refcnt);
+
                         /* Create volume node */
                         rc = sif_trans_begin(volume->volumes->repo, &trans);
@@ -426 +427 @@
                         volume->nvolume = nvolume;
                 } else {
+                        /* Allow volume to be freed */
+                        vol_volume_del_ref(volume);
+
                         /* Update volume node */
                         rc = sif_trans_begin(volume->volumes->repo, &trans);