1 files changed, 81 insertions, 8 deletions

diff --git a/fs/libfs.c b/fs/libfs.c
index 8c501849315..88e3e00e2ec 100644
--- a/fs/libfs.c
+++ b/fs/libfs.c
@@ -3,6 +3,7 @@
  *	Library for filesystems writers.
  */
 
+#include <linux/blkdev.h>
 #include <linux/export.h>
 #include <linux/pagemap.h>
 #include <linux/slab.h>
@@ -47,10 +48,16 @@ EXPORT_SYMBOL(simple_statfs);
  * Retaining negative dentries for an in-memory filesystem just wastes
  * memory and lookup time: arrange for them to be deleted immediately.
  */
-static int simple_delete_dentry(const struct dentry *dentry)
+int always_delete_dentry(const struct dentry *dentry)
 {
 	return 1;
 }
+EXPORT_SYMBOL(always_delete_dentry);
+
+const struct dentry_operations simple_dentry_operations = {
+	.d_delete = always_delete_dentry,
+};
+EXPORT_SYMBOL(simple_dentry_operations);
 
 /*
  * Lookup the data. This is trivial - if the dentry didn't already
@@ -58,10 +65,6 @@ static int simple_delete_dentry(const struct dentry *dentry)
  */
 struct dentry *simple_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
 {
-	static const struct dentry_operations simple_dentry_operations = {
-		.d_delete = simple_delete_dentry,
-	};
-
 	if (dentry->d_name.len > NAME_MAX)
 		return ERR_PTR(-ENAMETOOLONG);
 	if (!dentry->d_sb->s_d_op)
@@ -921,16 +924,19 @@ struct dentry *generic_fh_to_parent(struct super_block *sb, struct fid *fid,
 EXPORT_SYMBOL_GPL(generic_fh_to_parent);
 
 /**
- * generic_file_fsync - generic fsync implementation for simple filesystems
+ * __generic_file_fsync - generic fsync implementation for simple filesystems
+ *
  * @file:	file to synchronize
+ * @start:	start offset in bytes
+ * @end:	end offset in bytes (inclusive)
  * @datasync:	only synchronize essential metadata if true
  *
  * This is a generic implementation of the fsync method for simple
  * filesystems which track all non-inode metadata in the buffers list
  * hanging off the address_space structure.
  */
-int generic_file_fsync(struct file *file, loff_t start, loff_t end,
-		       int datasync)
+int __generic_file_fsync(struct file *file, loff_t start, loff_t end,
+				 int datasync)
 {
 	struct inode *inode = file->f_mapping->host;
 	int err;
@@ -950,10 +956,34 @@ int generic_file_fsync(struct file *file, loff_t start, loff_t end,
 	err = sync_inode_metadata(inode, 1);
 	if (ret == 0)
 		ret = err;
+
 out:
 	mutex_unlock(&inode->i_mutex);
 	return ret;
 }
+EXPORT_SYMBOL(__generic_file_fsync);
+
+/**
+ * generic_file_fsync - generic fsync implementation for simple filesystems
+ *			with flush
+ * @file:	file to synchronize
+ * @start:	start offset in bytes
+ * @end:	end offset in bytes (inclusive)
+ * @datasync:	only synchronize essential metadata if true
+ *
+ */
+
+int generic_file_fsync(struct file *file, loff_t start, loff_t end,
+		       int datasync)
+{
+	struct inode *inode = file->f_mapping->host;
+	int err;
+
+	err = __generic_file_fsync(file, start, end, datasync);
+	if (err)
+		return err;
+	return blkdev_issue_flush(inode->i_sb->s_bdev, GFP_KERNEL, NULL);
+}
 EXPORT_SYMBOL(generic_file_fsync);
 
 /**
@@ -1002,3 +1032,46 @@ void kfree_put_link(struct dentry *dentry, struct nameidata *nd,
 		kfree(s);
 }
 EXPORT_SYMBOL(kfree_put_link);
+
+/*
+ * nop .set_page_dirty method so that people can use .page_mkwrite on
+ * anon inodes.
+ */
+static int anon_set_page_dirty(struct page *page)
+{
+	return 0;
+};
+
+/*
+ * A single inode exists for all anon_inode files. Contrary to pipes,
+ * anon_inode inodes have no associated per-instance data, so we need
+ * only allocate one of them.
+ */
+struct inode *alloc_anon_inode(struct super_block *s)
+{
+	static const struct address_space_operations anon_aops = {
+		.set_page_dirty = anon_set_page_dirty,
+	};
+	struct inode *inode = new_inode_pseudo(s);
+
+	if (!inode)
+		return ERR_PTR(-ENOMEM);
+
+	inode->i_ino = get_next_ino();
+	inode->i_mapping->a_ops = &anon_aops;
+
+	/*
+	 * Mark the inode dirty from the very beginning,
+	 * that way it will never be moved to the dirty
+	 * list because mark_inode_dirty() will think
+	 * that it already _is_ on the dirty list.
+	 */
+	inode->i_state = I_DIRTY;
+	inode->i_mode = S_IRUSR | S_IWUSR;
+	inode->i_uid = current_fsuid();
+	inode->i_gid = current_fsgid();
+	inode->i_flags |= S_PRIVATE;
+	inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
+	return inode;
+}
+EXPORT_SYMBOL(alloc_anon_inode);