From mboxrd@z Thu Jan  1 00:00:00 1970
From: Boaz Harrosh <boaz@plexistor.com>
Subject: Re: Regression caused by using node_to_bdi()
Date: Mon, 13 Apr 2015 15:31:06 +0300
Message-ID: <552BB70A.3070603@plexistor.com>
References: <016d01d07380$fc37fc40$f4a7f4c0$@cn.fujitsu.com> <552A57F8.7020002@plexistor.com> <552A839C.4070101@plexistor.com> <030a01d075d3$cc1ebc60$645c3520$@cn.fujitsu.com>
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Cc: linux-fsdevel@vger.kernel.org, 'Jan Kara' <jack@suse.cz>,
	'Jens Axboe' <axboe@fb.com>,
	'LKML' <linux-kernel@vger.kernel.org>
To: Zhao Lei <zhaolei@cn.fujitsu.com>,
	'Boaz Harrosh' <boaz@plexistor.com>,
	'Christoph Hellwig' <hch@lst.de>
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On 04/13/2015 01:22 PM, Zhao Lei wrote:
<>
> A new bad news:
> This patch make filesystem unstable.
> 

Rrrr yes sorry Lei. Why this boots my systems is not clear this is not
what I intended to write.

Here is what I meant to write (replacing the old one):
----
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 32a8bbd..e0375e1 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -78,7 +78,7 @@ int writeback_in_progress(struct backing_dev_info *bdi)
 }
 EXPORT_SYMBOL(writeback_in_progress);
 
-struct backing_dev_info *inode_to_bdi(struct inode *inode)
+struct backing_dev_info *__inode_to_bdi(struct inode *inode)
 {
 	struct super_block *sb;
 
@@ -92,7 +92,7 @@ struct backing_dev_info *inode_to_bdi(struct inode *inode)
 #endif
 	return sb->s_bdi;
 }
-EXPORT_SYMBOL_GPL(inode_to_bdi);
+EXPORT_SYMBOL_GPL(__inode_to_bdi);
 
 static inline struct inode *wb_inode(struct list_head *head)
 {
diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h
index aff923a..53d97cd 100644
--- a/include/linux/backing-dev.h
+++ b/include/linux/backing-dev.h
@@ -107,7 +107,16 @@ struct backing_dev_info {
 #endif
 };
 
-struct backing_dev_info *inode_to_bdi(struct inode *inode);
+struct backing_dev_info *__inode_to_bdi(struct inode *inode);
+
+static inline
+struct backing_dev_info *inode_to_bdi(struct inode *inode)
+{
+	if (!inode || !inode->i_sb || !inode->i_sb->s_bdi)
+		return __inode_to_bdi(inode);
+
+	return inode->i_sb->s_bdi;
+}
 
 int __must_check bdi_init(struct backing_dev_info *bdi);
 void bdi_destroy(struct backing_dev_info *bdi);