orangefs: write range tracking

Attach the actual range of bytes written to plus the responsible uid/gid
to each dirty page.  This information must be sent to the server when
the page is written out.

Now write_begin, page_mkwrite, and invalidatepage keep up with this
information.  There are several conditions where they must write out the
page immediately to store the new range.  Two non-contiguous ranges
cannot be stored on a single page.
Signed-off-by: Martin Brandenburg <martin@omnibond.com>
Signed-off-by: Mike Marshall <hubcap@omnibond.com>

fs/orangefs/file.c

@@ -46,8 +46,8 @@ static int flush_racache(struct inode *inode)
  * Post and wait for the I/O upcall to finish
  */
 ssize_t wait_for_direct_io(enum ORANGEFS_io_type type, struct inode *inode,
-		loff_t *offset, struct iov_iter *iter,
-		size_t total_size, loff_t readahead_size)
+    loff_t *offset, struct iov_iter *iter, size_t total_size,
+    loff_t readahead_size, struct orangefs_write_range *wr)
 {
 	struct orangefs_inode_s *orangefs_inode = ORANGEFS_I(inode);
 	struct orangefs_khandle *handle = &orangefs_inode->refn.khandle;
@@ -85,6 +85,10 @@ ssize_t wait_for_direct_io(enum ORANGEFS_io_type type, struct inode *inode,
 	new_op->upcall.req.io.buf_index = buffer_index;
 	new_op->upcall.req.io.count = total_size;
 	new_op->upcall.req.io.offset = *offset;
+	if (type == ORANGEFS_IO_WRITE && wr) {
+		new_op->upcall.uid = from_kuid(&init_user_ns, wr->uid);
+		new_op->upcall.gid = from_kgid(&init_user_ns, wr->gid);
+	}
 
 	gossip_debug(GOSSIP_FILE_DEBUG,
 		     "%s(%pU): offset: %llu total_size: %zd\n",
@@ -329,7 +333,7 @@ static vm_fault_t orangefs_fault(struct vm_fault *vmf)
 static const struct vm_operations_struct orangefs_file_vm_ops = {
 	.fault = orangefs_fault,
 	.map_pages = filemap_map_pages,
-	.page_mkwrite = filemap_page_mkwrite,
+	.page_mkwrite = orangefs_page_mkwrite,
 };
 
 /*

fs/orangefs/orangefs-kernel.h

@@ -230,6 +230,13 @@ struct orangefs_cached_xattr {
 	unsigned long timeout;
 };
 
+struct orangefs_write_range {
+	loff_t pos;
+	size_t len;
+	kuid_t uid;
+	kgid_t gid;
+};
+
 extern struct orangefs_stats orangefs_stats;
 
 /*
@@ -342,6 +349,7 @@ void fsid_key_table_finalize(void);
 /*
  * defined in inode.c
  */
+vm_fault_t orangefs_page_mkwrite(struct vm_fault *);
 struct inode *orangefs_new_inode(struct super_block *sb,
 			      struct inode *dir,
 			      int mode,
@@ -383,7 +391,7 @@ bool __is_daemon_in_service(void);
  * defined in file.c
  */
 ssize_t wait_for_direct_io(enum ORANGEFS_io_type, struct inode *, loff_t *,
-    struct iov_iter *, size_t, loff_t);
+    struct iov_iter *, size_t, loff_t, struct orangefs_write_range *);
 ssize_t do_readv_writev(enum ORANGEFS_io_type, struct file *, loff_t *,
     struct iov_iter *);