Ansariel kindly offered their patch to help mitigate this round of file system issues - taken from https://vcs.firestormviewer.org/phoenix-firestorm/changeset/104a8600946be01e2de44d10ad069ba854272d1f

2 files changed, 29 insertions, 2 deletions

diff --git a/indra/llfilesystem/lldiskcache.cpp b/indra/llfilesystem/lldiskcache.cpp
index c9f7684b5a..61eb654693 100644
--- a/indra/llfilesystem/lldiskcache.cpp
+++ b/indra/llfilesystem/lldiskcache.cpp
@@ -192,8 +192,8 @@ const std::string LLDiskCache::metaDataToFilepath(const std::string id,
     file_path << id;
     file_path << "_";
     file_path << (extra_info.empty() ? "0" : extra_info);
-    //file_path << "_";
-    //file_path << assetTypeToString(at); // see  SL-14210 Prune descriptive tag from new cache filenames
+    file_path << "_";
+    file_path << assetTypeToString(at); // see  SL-14210 Prune descriptive tag from new cache filenames
                                           // for details of why it was removed. Note that if you put it
                                           // back or change the format of the filename, the cache files
                                           // files will be invalidated (and perhaps, more importantly,
diff --git a/indra/llfilesystem/llfilesystem.cpp b/indra/llfilesystem/llfilesystem.cpp
index 053b52014e..da44e8d98c 100644
--- a/indra/llfilesystem/llfilesystem.cpp
+++ b/indra/llfilesystem/llfilesystem.cpp
@@ -200,9 +200,36 @@ BOOL LLFileSystem::write(const U8* buffer, S32 bytes)
         {
             ofs.write((const char*)buffer, bytes);
 
+            mPosition = ofs.tellp(); // <FS:Ansariel> Fix asset caching
+
+            success = TRUE;
+        }
+    }
+    // <FS:Ansariel> Fix asset caching
+    else if (mMode == READ_WRITE)
+    {
+        // Don't truncate if file already exists
+        llofstream ofs(filename, std::ios::in | std::ios::binary);
+        if (ofs)
+        {
+            ofs.seekp(mPosition, std::ios::beg);
+            ofs.write((const char*)buffer, bytes);
+            mPosition += bytes;
             success = TRUE;
         }
+        else
+        {
+            // File doesn't exist - open in write mode
+            ofs.open(filename, std::ios::binary);
+            if (ofs.is_open())
+            {
+                ofs.write((const char*)buffer, bytes);
+                mPosition += bytes;
+                success = TRUE;
+            }
+        }
     }
+    // </FS:Ansariel>
     else
     {
         llofstream ofs(filename, std::ios::binary);