.

wcfs/client/wcfs.cpp

@@ -705,6 +705,7 @@ error _FileH::close() {
     // XXX decref open count
     // XXX fileh.close can be called several times and after first call another
     // XXX fileh could be opened for the same foid. Be careful not to interfere with it.
+    //     -> just return nil for second close
 
     // XXX locking ok?
     wconn->_atMu.RLock();
@@ -740,6 +741,16 @@ error _FileH::close() {
 // virtmem calls FileH::mmap under virtmem lock when virtmem fileh is mmapped into vma.
 pair<Mapping, error> _FileH::mmap(int64_t blk_start, int64_t blk_len, VMA *vma) {
     _FileH& f = *this;
+
+    // NOTE virtmem lock is held by virtmem caller
+    // XXX locking ok?
+    f.wconn->_atMu.RLock(); // e.g. f._headfsize
+    f._mu.lock();           // f._pinned, f._mmaps
+    defer([&]() {
+        f._mu.unlock();
+        f.wconn->_atMu.RUnlock();
+    });
+
     xerr::Contextf E("%s: mmap f<%s> [blk%ld +blk%ld)", v(f.wconn), v(f.foid), blk_start, blk_len);
 
     error err;
@@ -758,10 +769,6 @@ pair<Mapping, error> _FileH::mmap(int64_t blk_start, int64_t blk_len, VMA *vma)
         panic("(blk_start + blk_len)*f.blksize overflow int64");
     int64_t start    = blk_start*f.blksize;
 
-    // NOTE virtmem lock is held by virtmem caller
-    // XXX locking
-    // XXX + wconn.atMu.RLock() ? -> y (e.g. f.headfsize is used)
-    // f.mu.lock()
 
     // create memory with head/f mapping and applied pins
     // mmap-in zeros after f.size (else access to memory after file.size will raise SIGBUS)
@@ -828,11 +835,17 @@ pair<Mapping, error> _FileH::mmap(int64_t blk_start, int64_t blk_len, VMA *vma)
 error _Mapping::unmap() {
     Mapping mmap = newref(this);    // XXX newref for std::remove
     FileH f = mmap->fileh;
-    xerr::Contextf E("%s: f<%s>: unmap", v(f->wconn), v(f->foid));
 
     // NOTE virtmem lock is held by virtmem caller
-    // XXX locking
-    // wconn.atMu.RLock() + f.mu.lock()
+    // XXX locking ok?
+    f->wconn->_atMu.RLock();
+    f->_mu.lock();          // f._mmaps
+    defer([&]() {
+        f->_mu.unlock();
+        f->wconn->_atMu.RUnlock();
+    });
+
+    xerr::Contextf E("%s: f<%s>: unmap", v(f->wconn), v(f->foid));
 
     if (mmap->vma != nil) {
         mmap->_assertVMAOk();