diff --git a/encfs/BlockFileIO.cpp b/encfs/BlockFileIO.cpp
index adadaa3..11c46de 100644
--- a/encfs/BlockFileIO.cpp
+++ b/encfs/BlockFileIO.cpp
@@ -101,7 +101,7 @@ int BlockFileIO::cacheWriteOneBlock(const IORequest &req) {
   _cache.offset = req.offset;
   _cache.dataLen = req.dataLen;
   int res = writeOneBlock(req);
-  if (res) clearCache(_cache, _blockSize);
+  if (res < 0) clearCache(_cache, _blockSize);
   return res;
 }
 
@@ -201,7 +201,7 @@ int BlockFileIO::write(const IORequest &req) {
     // extend file first to fill hole with 0's..
     const bool forceWrite = false;
     int res = padFile(fileSize, req.offset, forceWrite);
-    if (res)
+    if (res < 0)
       return res;
   }
 
@@ -266,7 +266,7 @@ int BlockFileIO::write(const IORequest &req) {
 
     // Finally, write the damn thing!
     res = cacheWriteOneBlock(blockReq);
-    if (res) {
+    if (res < 0) {
       break;
     }
 
@@ -342,7 +342,7 @@ int BlockFileIO::padFile(off_t oldSize, off_t newSize, bool forceWrite) {
 
     // 2, pad zero blocks unless holes are allowed
     if (!_allowHoles) {
-      for (; !res && (oldLastBlock != newLastBlock); ++oldLastBlock) {
+      for (; !(res < 0) && (oldLastBlock != newLastBlock); ++oldLastBlock) {
         VLOG(1) << "padding block " << oldLastBlock;
         req.offset = oldLastBlock * _blockSize;
         req.dataLen = _blockSize;
@@ -352,7 +352,7 @@ int BlockFileIO::padFile(off_t oldSize, off_t newSize, bool forceWrite) {
     }
 
     // 3. only necessary if write is forced and block is non 0 length
-    if (!res && forceWrite && newBlockSize) {
+    if (!(res < 0) && forceWrite && newBlockSize) {
       req.offset = newLastBlock * _blockSize;
       req.dataLen = newBlockSize;
       memset(mb.data, 0, req.dataLen);
@@ -379,7 +379,7 @@ int BlockFileIO::truncateBase(off_t size, FileIO *base) {
     if (base) res = base->truncate(size);
 
     const bool forceWrite = true;
-    if (!res)
+    if (!(res < 0))
       res = padFile(oldSize, size, forceWrite);
   } else if (size == oldSize) {
     // the easiest case, but least likely....
diff --git a/encfs/CipherFileIO.cpp b/encfs/CipherFileIO.cpp
index fae102b..6cf9282 100644
--- a/encfs/CipherFileIO.cpp
+++ b/encfs/CipherFileIO.cpp
@@ -222,7 +222,7 @@ int CipherFileIO::initHeader() {
       req.dataLen = 8;
 
       int res = base->write(req);
-      if (res)
+      if (res < 0)
         return res;
     } else {
       VLOG(1) << "base not writable, IV not written..";
@@ -252,7 +252,7 @@ bool CipherFileIO::writeHeader() {
   req.data = buf;
   req.dataLen = 8;
 
-  if (base->write(req))
+  if (base->write(req) < 0)
     return false;
 
   return true;
@@ -461,7 +461,7 @@ int CipherFileIO::truncate(off_t size) {
     // the wrong size..
     res = BlockFileIO::truncateBase(size, 0);
 
-    if (res == 0) res = base->truncate(size + HEADER_SIZE);
+    if (!(res < 0)) res = base->truncate(size + HEADER_SIZE);
   }
   return res;
 }
diff --git a/encfs/MACFileIO.cpp b/encfs/MACFileIO.cpp
index 15bb032..9a17c7b 100644
--- a/encfs/MACFileIO.cpp
+++ b/encfs/MACFileIO.cpp
@@ -253,7 +253,7 @@ int MACFileIO::truncate(off_t size) {
 
   int res = BlockFileIO::truncateBase(size, 0);
 
-  if (res == 0) res = base->truncate(locWithHeader(size, bs, headerSize));
+  if (!(res < 0)) res = base->truncate(locWithHeader(size, bs, headerSize));
 
   return res;
 }
diff --git a/encfs/RawFileIO.cpp b/encfs/RawFileIO.cpp
index b2cbb26..231970d 100644
--- a/encfs/RawFileIO.cpp
+++ b/encfs/RawFileIO.cpp
@@ -246,7 +246,7 @@ int RawFileIO::write(const IORequest &req) {
       if (last > fileSize) fileSize = last;
     }
 
-    return 0;
+    return 0; //No matter how many bytes we wrote, we of course already know this.
   }
 }
 
diff --git a/encfs/encfs.cpp b/encfs/encfs.cpp
index ad0acec..64a47b0 100644
--- a/encfs/encfs.cpp
+++ b/encfs/encfs.cpp
@@ -616,10 +616,10 @@ int encfs_fsync(const char *path, int dataSync, struct fuse_file_info *file) {
 
 int _do_write(FileNode *fnode, unsigned char *ptr, size_t size, off_t offset) {
   int res = fnode->write(offset, ptr, size);
-  if (!res)
-    return size;
-  else
+  if (res < 0)
     return res;
+  else
+    return size;
 }
 
 int encfs_write(const char *path, const char *buf, size_t size, off_t offset,