.

wcfs/client/wcfs.cpp

@@ -22,7 +22,15 @@
 
 // Wcfs client organization
 //
-// - need to maintain pinner map registry
+// Wcfs client provides to its users isolated bigfile views backed by data on
+// WCFS filesystem. In the absence of Isolation property, wcfs client would
+// reduce to just directly using OS-level file wcfs/head/f for a bigfile f. On
+// the other hand there is a simple, but inefficient, way to support isolation:
+// for @at database view of bigfile f - directly use OS-level file wcfs/@at/f.
+//
+//
+//
+// - need to maintain pinner map registry   XXX no need
 //
 //      [blk< +len) -> vma      ↓blk
 //      #blk        -> []vma covering it
@@ -55,7 +63,7 @@
 // synchronously from other threads via messages coming through wcfs server.
 // For example Conn.resync sends watch request to wcfs and waits for the
 // answer. Wcfs server, in turn, might send corresponding pin messages to the
-// pinner and _wait_ for the answere before answering to resync:
+// pinner and _wait_ for the answer before answering to resync:
 //
 //        - - - - - -
 //       |       .···|·····.        ---->   = request
@@ -66,8 +74,8 @@
 //        - - - - - -
 //       client process
 //
-// This creates the neccessity to use RWMutex for locks that pinner and other
-// parts of the code could be using at the same time in sychronous mode similar
+// This creates the necessity to use RWMutex for locks that pinner and other
+// parts of the code could be using at the same time in synchronous mode similar
 // to the above. This locks are:
 //
 //      - Conn.atMu
@@ -497,7 +505,7 @@ error _FileH::close() {
     xerr::Contextf E("%s: close f<%s>", v(wconn), v(fileh.foid));
 
     // XXX change all fileh.mmaps to cause EFAULT on any access after fileh.close
-    // XXX "watch foid -" -> wconn.wlink (stop watchingthe file)
+    // XXX "watch foid -" -> wconn.wlink (stop watching the file)
 
     // remove fileh from wconn._filehTab
     // fileh.close can be called several times and after first call another
@@ -609,10 +617,10 @@ error _Conn::resync(zodb::Tid at) {
     }
 
     // atomically downgrade atMu.W to atMu.R before issuing watch updates to wcfs.
-    // - we need atMu to be not Wlocked, because under atMu.W pinner cannot run simultanesouly to us.
+    // - we need atMu to be not Wlocked, because under atMu.W pinner cannot run simultaneously to us.
     // - we need to hold atMu.R to avoid race wrt e.g. other resync which changes at.
     // - we cannot just do regular `atMu.Unlock + atMu.RLock()` because then
-    //   there is a race window inbetween Unlock and RLock where wconn.at can be changed.
+    //   there is a race window in between Unlock and RLock where wconn.at can be changed.
     //   XXX also deadlock, because it will become wconn._mu.lock + wconn._atMu lock
     //
     // Now other calls, e.g. Conn.open, can be running simultaneously to us,
@@ -915,7 +923,7 @@ static error mmap_into_ro(void *addr, size_t size, os::File f, off_t offset) {
 
 
 // _assertVMAOk() verifies that mmap and vma are related to each other and cover
-// exactly the same virtual memory rane.
+// exactly the same virtual memory range.
 //
 // It panics if mmap and vma do not exactly relate to each other or cover
 // different virtual memory range.