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f2fs: fix cgroup writeback accounting with fs-layer encryption

PATCH In review Eric Biggers 2 participants 2 messages Mar 8, 2023 – Mar 10, 2023

Subsystems (2)
Stable branch fscrypt: file system level encryption support
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Eric Biggers

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PATCH 1/1 f2fs: fix cgroup writeback accounting with fs-layer encryption

From: Eric Biggers <[email protected]>

commit 844545c51a5b2a524b22a2fe9d0b353b827d24b4 upstream.

When writing a page from an encrypted file that is using filesystem-layer encryption (not inline encryption), f2fs 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 578c647879f7 ("f2fs: implement cgroup writeback support")
Cc [email protected]
Reported-by Matthew Wilcox (Oracle) <[email protected]>
Signed-off-by Eric Biggers <[email protected]>
Acked-by Tejun Heo <[email protected]>
Reviewed-by Chao Yu <[email protected]>
Signed-off-by Jaegeuk Kim <[email protected]>
---
 fs/f2fs/data.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
fs/f2fs/data.c +2 -2
index c63f5e32630ee..56b2dadd623b2 100644
@@ -464,7 +464,7 @@ int f2fs_submit_page_bio(struct f2fs_io_info *fio)
 	}
 
 	if (fio->io_wbc && !is_read_io(fio->op))
-		wbc_account_io(fio->io_wbc, page, PAGE_SIZE);
+		wbc_account_io(fio->io_wbc, fio->page, PAGE_SIZE);
 
 	bio_set_op_attrs(bio, fio->op, fio->op_flags);
 

@@ -533,7 +533,7 @@ void f2fs_submit_page_write(struct f2fs_io_info *fio)
 	}
 
 	if (fio->io_wbc)
-		wbc_account_io(fio->io_wbc, bio_page, PAGE_SIZE);
+		wbc_account_io(fio->io_wbc, fio->page, PAGE_SIZE);
 
 	io->last_block_in_bio = fio->new_blkaddr;
 	f2fs_trace_ios(fio, 0);
Signature · 1 line
2.39.2
#1 lore raw
Quoted 24 lines · Eric Biggers

From: Eric Biggers <[email protected]>

commit 844545c51a5b2a524b22a2fe9d0b353b827d24b4 upstream.

When writing a page from an encrypted file that is using filesystem-layer encryption (not inline encryption), f2fs 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 578c647879f7 ("f2fs: implement cgroup writeback support")
Cc [email protected]
Reported-by Matthew Wilcox (Oracle) <[email protected]>
Signed-off-by Eric Biggers <[email protected]>
Acked-by Tejun Heo <[email protected]>
Reviewed-by Chao Yu <[email protected]>
Signed-off-by Jaegeuk Kim <[email protected]>
Quoted 3 lines
---
 fs/f2fs/data.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Now queued up, thanks.

greg k-h