libglusterfsclient: Use iobufs for storing application write data

Till now we've been creating an iovec, storing references in it
to the application data and simply passing it on to the translator
tree. This means that the buffer being passed to the translators is
not at all associated with the memory ref'd by the iobref argument
to write fop. This is a problem when write-behind is a translator in
the tree since it assumes that the memory in the iovecs passed to
write fops is already refcounted by the iobref and so it simply copies
the address of the application data. The problem is that the application
can continue using this buffer, free it or over-write it destroying the
data that write-behind may write at a later time.

The solution involves copying the application's write buffer into
an iobuf which will be referred to by the iobref.

Signed-off-by: Anand V. Avati <avati@dev.gluster.com>

BUG: 178 (libglusterfsclient: Data corruption on using write-behind in translator tree)
URL: http://bugs.gluster.com/cgi-bin/bugzilla3/show_bug.cgi?id=178

1 files changed, 1 insertions, 0 deletions

diff --git a/libglusterfsclient/src/libglusterfsclient-internals.h b/libglusterfsclient/src/libglusterfsclient-internals.h
index 09acf33e8c5..bdbdd744ba3 100755
--- a/libglusterfsclient/src/libglusterfsclient-internals.h
+++ b/libglusterfsclient/src/libglusterfsclient-internals.h
@@ -33,6 +33,7 @@
 #include <fd.h>
 #include <dirent.h>
 
+#define LIBGF_IOBUF_SIZE        (128 *GF_UNIT_KB)
 typedef void (*sighandler_t) (int);
 typedef struct list_head list_head_t;