The patch below does not apply to the 4.9-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 0ea295dd853e0879a9a30ab61f923c26be35b902 Mon Sep 17 00:00:00 2001

From: Pan Bian bianpan2016@163.com Date: Thu, 22 Nov 2018 18:58:46 +0800 Subject: [PATCH] f2fs: read page index before freeing

The function truncate_node frees the page with f2fs_put_page. However, the page index is read after that. So, the patch reads the index before freeing the page.

Fixes: bf39c00a9a7f ("f2fs: drop obsolete node page when it is truncated") Cc: stable@vger.kernel.org Signed-off-by: Pan Bian bianpan2016@163.com Reviewed-by: Chao Yu yuchao0@huawei.com Signed-off-by: Jaegeuk Kim jaegeuk@kernel.org

diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c index e60c7779e114..a2273340991f 100644 --- a/fs/f2fs/node.c +++ b/fs/f2fs/node.c @@ -826,6 +826,7 @@ static int truncate_node(struct dnode_of_data *dn) struct f2fs_sb_info *sbi = F2FS_I_SB(dn->inode); struct node_info ni; int err; + pgoff_t index;

err = f2fs_get_node_info(sbi, dn->nid, &ni); if (err) @@ -845,10 +846,11 @@ static int truncate_node(struct dnode_of_data *dn) clear_node_page_dirty(dn->node_page); set_sbi_flag(sbi, SBI_IS_DIRTY);

+ index = dn->node_page->index; f2fs_put_page(dn->node_page, 1);

invalidate_mapping_pages(NODE_MAPPING(sbi), - dn->node_page->index, dn->node_page->index); + index, index);

dn->node_page = NULL; trace_f2fs_truncate_node(dn->inode, dn->nid, ni.blk_addr);