This is a note to let you know that I've just added the patch titled ext4: enforce buffer head state assertion in ext4_da_map_blocks to the 5.14-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: ext4-enforce-buffer-head-state-assertion-in-ext4_da_.patch and it can be found in the queue-5.14 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit b2838e02c515366e8452370fcda5baa2dcc8be68 Author: Eric Whitney <enwlinux@xxxxxxxxx> Date: Thu Aug 19 10:49:27 2021 -0400 ext4: enforce buffer head state assertion in ext4_da_map_blocks [ Upstream commit 948ca5f30e1df0c11eb5b0f410b9ceb97fa77ad9 ] 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 <enwlinux@xxxxxxxxx> Signed-off-by: Theodore Ts'o <tytso@xxxxxxx> Link: https://lore.kernel.org/r/20210819144927.25163-3-enwlinux@xxxxxxxxx Signed-off-by: Theodore Ts'o <tytso@xxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index fc6ea56de77c..d204688b32a3 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -1726,13 +1726,16 @@ 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; }