Changeset 69165 in vbox for trunk/src/VBox/Additions/linux/sharedfolders

Timestamp:

Oct 23, 2017 3:11:37 PM (7 years ago)

Author:

vboxsync

Message:

Additions/linux/sharedfolders: stop using generic caching I/O functions.
bugref:2548: Complete shared folders filesystem for Linux guests

Our shared folder file-system driver currently makes use of generic
implementations of read_iter, write_iter and send_file which assume that file-
system data may safely be cached. This does not apply to our shared folders
driver. For kernels 2.6.31 and later we can simply stop using those
functions and the kernel will fall back to defaults which work for us. For
older kernels this still needs to be fixed, and is visible when files are
memory-mapped. See public bugs #819 and #17053.

Fix contributed by David Ellingsworth <david@…>.

File:

• trunk/src/VBox/Additions/linux/sharedfolders/regops.c (modified) (1 diff)

trunk/src/VBox/Additions/linux/sharedfolders/regops.c

@@ -563 +563 @@
     .mmap        = sf_reg_mmap,
 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 0)
-# if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 23)
+# if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 31)
+/** @todo This code is known to cause caching of data which should not be
+ * cached.  Investigate. */
+#  if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 23)
     .splice_read = generic_file_splice_read,
-# else
+#  else
     .sendfile    = generic_file_sendfile,
-# endif
-# if LINUX_VERSION_CODE >= KERNEL_VERSION(3, 16, 0)
-    .read_iter   = generic_file_read_iter,
-    .write_iter  = generic_file_write_iter,
-# else
+#  endif
     .aio_read    = generic_file_aio_read,
     .aio_write   = generic_file_aio_write,