From 373b4fe92ecbf74a4500b365ac9a727c716afe35 Mon Sep 17 00:00:00 2001 From: Eric Whitney Date: Thu, 19 Aug 2021 10:49:27 -0400 Subject: [PATCH] ext4: enforce buffer head state assertion in ext4_da_map_blocks Remove the code that re-initializes a buffer head with an invalid block number and BH_New and BH_Delay bits when a matching delayed and unwritten block has been found in the extent status cache. Replace it with assertions that verify the buffer head already has this state correctly set. The current code masked an inline data truncation bug that left stale entries in the extent status cache. With this change, generic/130 can be used to reproduce and detect that bug. Signed-off-by: Eric Whitney Signed-off-by: Theodore Ts'o Link: https://lore.kernel.org/r/20210819144927.25163-3-enwlinux@gmail.com Signed-off-by: Theodore Ts'o --- fs/ext4/inode.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-) diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 8204176256c86..2a076d236ba11 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -1706,13 +1706,16 @@ static int ext4_da_map_blocks(struct inode *inode, sector_t iblock, } /* - * Delayed extent could be allocated by fallocate. - * So we need to check it. + * the buffer head associated with a delayed and not unwritten + * block found in the extent status cache must contain an + * invalid block number and have its BH_New and BH_Delay bits + * set, reflecting the state assigned when the block was + * initially delayed allocated */ - if (ext4_es_is_delayed(&es) && !ext4_es_is_unwritten(&es)) { - map_bh(bh, inode->i_sb, invalid_block); - set_buffer_new(bh); - set_buffer_delay(bh); + if (ext4_es_is_delonly(&es)) { + BUG_ON(bh->b_blocknr != invalid_block); + BUG_ON(!buffer_new(bh)); + BUG_ON(!buffer_delay(bh)); return 0; } -- 2.39.5