Linux 3.2 compat: set_nlink()

Directly changing inode->i_nlink is deprecated in Linux 3.2 by commit

  SHA: bfe8684869601dacfcb2cd69ef8cfd9045f62170

Use the new set_nlink() kernel function instead.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes: #462

include/linux/Makefile.in

@@ -70,6 +70,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/kernel-rq-for-each_segment.m4 \
 	$(top_srcdir)/config/kernel-rq-is_sync.m4 \
 	$(top_srcdir)/config/kernel-security-inode-init.m4 \
+	$(top_srcdir)/config/kernel-set-nlink.m4 \
 	$(top_srcdir)/config/kernel-truncate-setsize.m4 \
 	$(top_srcdir)/config/kernel-xattr-handler.m4 \
 	$(top_srcdir)/config/kernel.m4 \

include/linux/vfs_compat.h

@@ -94,4 +94,19 @@ bdi_setup_and_register(struct backing_dev_info *bdi,char *name,unsigned int cap)
 }
 #endif /* HAVE_BDI && !HAVE_BDI_SETUP_AND_REGISTER */
 
+/*
+ * 3.2-rc1 API change,
+ * Add set_nlink() if it is not exported by the Linux kernel.
+ *
+ * i_nlink is read-only in Linux 3.2, but it can be set directly in
+ * earlier kernels.
+ */
+#ifndef HAVE_SET_NLINK
+static inline void
+set_nlink(struct inode *inode, unsigned int nlink)
+{
+	inode->i_nlink = nlink;
+}
+#endif /* HAVE_SET_NLINK */
+
 #endif /* _ZFS_VFS_H */