Patch "f2fs: fix a bug caused by NULL extent tree" has been added to the 4.9-stable tree

This is a note to let you know that I've just added the patch titled

f2fs: fix a bug caused by NULL extent tree

to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
f2fs-fix-a-bug-caused-by-null-extent-tree.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Yunlei He <[email protected]>
Date: Fri, 19 May 2017 15:06:12 +0800
Subject: f2fs: fix a bug caused by NULL extent tree

From: Yunlei He <[email protected]>

commit dad48e73127ba10279ea33e6dbc8d3905c4d31c0 upstream.

Thread A: Thread B:

-f2fs_remount

    -sbi->mount_opt.opt = 0;
						<--- -f2fs_iget
						         -do_read_inode
							     -f2fs_init_extent_tree
							         -F2FS_I(inode)->extent_tree is NULL
        -default_options && parse_options
	    -remount return
						<---  -f2fs_map_blocks
						          -f2fs_lookup_extent_tree
                                                              -f2fs_bug_on(sbi, !et);

The same problem with f2fs_new_inode.

---
 fs/f2fs/extent_cache.c |   12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

@@ -177,7 +177,7 @@ static void __drop_largest_extent(struct
 }
 
 /* return true, if inode page is changed */
-bool f2fs_init_extent_tree(struct inode *inode, struct f2fs_extent *i_ext)
+static bool __f2fs_init_extent_tree(struct inode *inode, struct f2fs_extent *i_ext)
 {
 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
 	struct extent_tree *et;

@@ -215,6 +215,16 @@ out:
 	return false;
 }
 
+bool f2fs_init_extent_tree(struct inode *inode, struct f2fs_extent *i_ext)
+{
+	bool ret =  __f2fs_init_extent_tree(inode, i_ext);
+
+	if (!F2FS_I(inode)->extent_tree)
+		set_inode_flag(inode, FI_NO_EXTENT);
+
+	return ret;
+}
+
 static bool f2fs_lookup_extent_tree(struct inode *inode, pgoff_t pgofs,
 							struct extent_info *ei)
 {

Patches currently in stable-queue which might be from [email protected] are

queue-4.9/f2fs-fix-a-bug-caused-by-null-extent-tree.patch