From f4952688ebe4447ce9e8b98068fd9f42d26c6baf Mon Sep 17 00:00:00 2001
From: Jan Kara <jack@suse.cz>
Date: Mon, 27 Jun 2011 16:18:10 -0700
Subject: [PATCH] --- yaml --- r: 254107 b: refs/heads/master c:
 08142579b6ca35883c1ed066a2681de6f6917062 h: refs/heads/master i:   254105:
 b964aa17fdcbb23073e109554a6db44ddfbda8f0   254103:
 0039840dabdb856805b4dd5c9a38341fb97662bf v: v3

---
 [refs]                   | 2 +-
 trunk/fs/inode.c         | 7 +++++++
 trunk/include/linux/fs.h | 1 +
 trunk/mm/truncate.c      | 5 +++++
 4 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/[refs] b/[refs]
index d0d6f009e57a..f09281b0a936 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 9b679320a5fbf46454011e5c62e0b8991b0956d1
+refs/heads/master: 08142579b6ca35883c1ed066a2681de6f6917062
diff --git a/trunk/fs/inode.c b/trunk/fs/inode.c
index 0f7e88a7803f..43566d17d1b8 100644
--- a/trunk/fs/inode.c
+++ b/trunk/fs/inode.c
@@ -423,7 +423,14 @@ EXPORT_SYMBOL(remove_inode_hash);
 void end_writeback(struct inode *inode)
 {
 	might_sleep();
+	/*
+	 * We have to cycle tree_lock here because reclaim can be still in the
+	 * process of removing the last page (in __delete_from_page_cache())
+	 * and we must not free mapping under it.
+	 */
+	spin_lock_irq(&inode->i_data.tree_lock);
 	BUG_ON(inode->i_data.nrpages);
+	spin_unlock_irq(&inode->i_data.tree_lock);
 	BUG_ON(!list_empty(&inode->i_data.private_list));
 	BUG_ON(!(inode->i_state & I_FREEING));
 	BUG_ON(inode->i_state & I_CLEAR);
diff --git a/trunk/include/linux/fs.h b/trunk/include/linux/fs.h
index 6e73e2e9ae33..b5b979247863 100644
--- a/trunk/include/linux/fs.h
+++ b/trunk/include/linux/fs.h
@@ -639,6 +639,7 @@ struct address_space {
 	struct prio_tree_root	i_mmap;		/* tree of private and shared mappings */
 	struct list_head	i_mmap_nonlinear;/*list VM_NONLINEAR mappings */
 	struct mutex		i_mmap_mutex;	/* protect tree, count, list */
+	/* Protected by tree_lock together with the radix tree */
 	unsigned long		nrpages;	/* number of total pages */
 	pgoff_t			writeback_index;/* writeback starts here */
 	const struct address_space_operations *a_ops;	/* methods */
diff --git a/trunk/mm/truncate.c b/trunk/mm/truncate.c
index 29a9b8a5a31a..e13f22efaad7 100644
--- a/trunk/mm/truncate.c
+++ b/trunk/mm/truncate.c
@@ -304,6 +304,11 @@ EXPORT_SYMBOL(truncate_inode_pages_range);
  * @lstart: offset from which to truncate
  *
  * Called under (and serialised by) inode->i_mutex.
+ *
+ * Note: When this function returns, there can be a page in the process of
+ * deletion (inside __delete_from_page_cache()) in the specified range.  Thus
+ * mapping->nrpages can be non-zero when this function returns even after
+ * truncation of the whole mapping.
  */
 void truncate_inode_pages(struct address_space *mapping, loff_t lstart)
 {