fuse: Implement write syscall (RHBZ#592883).

fuse/guestmount.c

@@ -653,7 +653,17 @@ fg_write (const char *path, const char *buf, size_t size,
 
   dir_cache_invalidate (path);
 
-  return -ENOSYS;               /* XXX */
+  /* See fg_read. */
+  const size_t limit = 2 * 1024 * 1024;
+  if (size > limit)
+    size = limit;
+
+  int r;
+  r = guestfs_pwrite (g, path, buf, size, offset);
+  if (r == -1)
+    return error ();
+
+  return r;
 }
 
 static int

fuse/test-fuse.sh

@@ -207,6 +207,17 @@ for ts in 12345 1234567 987654321; do
     [ "$(stat -c %Y timestamp)" -eq $ts ]
 done
 
+stage Checking writes
+cp hello.txt copy.txt
+echo >> copy.txt
+echo world >> copy.txt
+echo bigger >> copy.txt
+echo biggest >> copy.txt
+[ "$(cat copy.txt)" = "hello
+world
+bigger
+biggest" ]
+
 # These ones are not yet tested by the current script:
 #stage XXX statfs/statvfs
 #stage XXX xattr operations