From: Qu Wenruo <wqu@suse.com>
To: linux-btrfs@vger.kernel.org
Subject: [PATCH 0/2] btrfs: fix btrfs_file_extent_item::ram_bytes of btrfs_split_ordered_extent()
Date: Tue, 16 Apr 2024 08:54:04 +0930 [thread overview]
Message-ID: <cover.1713223082.git.wqu@suse.com> (raw)
During my extent_map members rework, I added a sanity check to make sure
regular non-compressed extent_map would have its disk_num_bytes to match
ram_bytes.
But that extent_map sanity check always fail as we have on-disk file
extent items which has its ram_bytes much larger than the corresponding
disk_num_bytes, even if it's not compressed.
It turns out that, the ram_bytes > disk_num_bytes is caused by
btrfs_split_ordered_extent(), where it doesn't properly update
ram_bytes, resulting it larger than disk_num_bytes.
Thankfully everything is fine, as our code doesn't really bother
ram_bytes for non-compressed regular file extents, so no real damage.
Still I'd like to catch such problem in the future, so add another
tree-checker patch for this case.
And since the invalid ram_bytes is already in the wild for a while, we
do not want to bother the end users to fix their fs for nothing.
So the check is only behind DEBUG builds.
Furthermore, the tree-checker is only to make sure @ram_bytes <
@disk_num_bytes for non-compressed file extents.
As we still have other locations to make @ram_bytes < @disk_num_bytes.
And for btrfs-progs, I'm going to add extra check and repair support
soon.
Qu Wenruo (2):
btrfs: set correct ram_bytes when splitting ordered extent
btrfs: tree-checker: add one extra file extent item ram_bytes check
fs/btrfs/ordered-data.c | 1 +
fs/btrfs/tree-checker.c | 35 +++++++++++++++++++++++++++++------
2 files changed, 30 insertions(+), 6 deletions(-)
--
2.44.0
next reply other threads:[~2024-04-15 23:24 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-15 23:24 Qu Wenruo [this message]
2024-04-15 23:24 ` [PATCH 1/2] btrfs: set correct ram_bytes when splitting ordered extent Qu Wenruo
2024-04-16 11:38 ` Filipe Manana
2024-04-15 23:24 ` [PATCH 2/2] btrfs: tree-checker: add one extra file extent item ram_bytes check Qu Wenruo
2024-04-16 11:41 ` Filipe Manana
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