This is a note to let you know that I've just added the patch titled
ext4: fix cgroup writeback accounting with fs-layer encryption
to the 5.15-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-fix-cgroup-writeback-accounting-with-fs-layer-encryption.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From ffec85d53d0f39ee4680a2cf0795255e000e1feb Mon Sep 17 00:00:00 2001
From: Eric Biggers <ebiggers@xxxxxxxxxx>
Date: Thu, 2 Feb 2023 16:55:03 -0800
Subject: ext4: fix cgroup writeback accounting with fs-layer encryption
From: Eric Biggers <ebiggers@xxxxxxxxxx>
commit ffec85d53d0f39ee4680a2cf0795255e000e1feb upstream.
When writing a page from an encrypted file that is using
filesystem-layer encryption (not inline encryption), ext4 encrypts the
pagecache page into a bounce page, then writes the bounce page.
It also passes the bounce page to wbc_account_cgroup_owner(). That's
incorrect, because the bounce page is a newly allocated temporary page
that doesn't have the memory cgroup of the original pagecache page.
This makes wbc_account_cgroup_owner() not account the I/O to the owner
of the pagecache page as it should.
Fix this by always passing the pagecache page to
wbc_account_cgroup_owner().
Fixes: 001e4a8775f6 ("ext4: implement cgroup writeback support")
Cc: stable@xxxxxxxxxxxxxxx
Reported-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Signed-off-by: Eric Biggers <ebiggers@xxxxxxxxxx>
Acked-by: Tejun Heo <tj@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20230203005503.141557-1-ebiggers@xxxxxxxxxx
Signed-off-by: Theodore Ts'o <tytso@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/ext4/page-io.c | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)
--- a/fs/ext4/page-io.c
+++ b/fs/ext4/page-io.c
@@ -413,7 +413,8 @@ static void io_submit_init_bio(struct ex
static void io_submit_add_bh(struct ext4_io_submit *io,
struct inode *inode,
- struct page *page,
+ struct page *pagecache_page,
+ struct page *bounce_page,
struct buffer_head *bh)
{
int ret;
@@ -427,10 +428,11 @@ submit_and_retry:
io_submit_init_bio(io, bh);
io->io_bio->bi_write_hint = inode->i_write_hint;
}
- ret = bio_add_page(io->io_bio, page, bh->b_size, bh_offset(bh));
+ ret = bio_add_page(io->io_bio, bounce_page ?: pagecache_page,
+ bh->b_size, bh_offset(bh));
if (ret != bh->b_size)
goto submit_and_retry;
- wbc_account_cgroup_owner(io->io_wbc, page, bh->b_size);
+ wbc_account_cgroup_owner(io->io_wbc, pagecache_page, bh->b_size);
io->io_next_block++;
}
@@ -548,8 +550,7 @@ int ext4_bio_write_page(struct ext4_io_s
do {
if (!buffer_async_write(bh))
continue;
- io_submit_add_bh(io, inode,
- bounce_page ? bounce_page : page, bh);
+ io_submit_add_bh(io, inode, page, bounce_page, bh);
nr_submitted++;
clear_buffer_dirty(bh);
} while ((bh = bh->b_this_page) != head);
Patches currently in stable-queue which might be from ebiggers@xxxxxxxxxx are
queue-5.15/ext4-fix-cgroup-writeback-accounting-with-fs-layer-encryption.patch
