From af64015b4f713ad1d63761c3d5c0f1e486677a72 Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Tue, 13 Jun 2017 16:20:25 +0200 Subject: [PATCH] udf: Fix deadlock between writeback and udf_setsize() commit f2e95355891153f66d4156bf3a142c6489cd78c6 upstream. udf_setsize() called truncate_setsize() with i_data_sem held. Thus truncate_pagecache() called from truncate_setsize() could lock a page under i_data_sem which can deadlock as page lock ranks below i_data_sem - e. g. writeback can hold page lock and try to acquire i_data_sem to map a block. Fix the problem by moving truncate_setsize() calls from under i_data_sem. It is safe for us to change i_size without holding i_data_sem as all the places that depend on i_size being stable already hold inode_lock. Fixes: 7e49b6f2480cb9a9e7322a91592e56a5c85361f5 Signed-off-by: Jan Kara [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings --- fs/udf/inode.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/fs/udf/inode.c b/fs/udf/inode.c index 5d67e2023311e..68de1c75237aa 100644 --- a/fs/udf/inode.c +++ b/fs/udf/inode.c @@ -1145,8 +1145,8 @@ int udf_setsize(struct inode *inode, loff_t newsize) up_write(&iinfo->i_data_sem); return err; } - truncate_setsize(inode, newsize); up_write(&iinfo->i_data_sem); + truncate_setsize(inode, newsize); } else { if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB) { down_write(&iinfo->i_data_sem); @@ -1162,8 +1162,8 @@ int udf_setsize(struct inode *inode, loff_t newsize) udf_get_block); if (err) return err; - down_write(&iinfo->i_data_sem); truncate_setsize(inode, newsize); + down_write(&iinfo->i_data_sem); udf_truncate_extents(inode); up_write(&iinfo->i_data_sem); } -- 2.47.2