This is a note to let you know that I've just added the patch titled
btrfs: prevent __btrfs_dump_space_info() to underflow its free space
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:
btrfs-prevent-__btrfs_dump_space_info-to-underflow-its-free-space.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.
>From 0619b7901473c380abc05d45cf9c70bee0707db3 Mon Sep 17 00:00:00 2001
From: Qu Wenruo <wqu@xxxxxxxx>
Date: Thu, 16 Sep 2021 20:43:29 +0800
Subject: btrfs: prevent __btrfs_dump_space_info() to underflow its free space
From: Qu Wenruo <wqu@xxxxxxxx>
commit 0619b7901473c380abc05d45cf9c70bee0707db3 upstream.
It's not uncommon where __btrfs_dump_space_info() gets called
under over-commit situations.
In that case free space would underflow as total allocated space is not
enough to handle all the over-committed space.
Such underflow values can sometimes cause confusion for users enabled
enospc_debug mount option, and takes some seconds for developers to
convert the underflow value to signed result.
Just output the free space as s64 to avoid such problem.
Reported-by: Eli V <eliventer@xxxxxxxxx>
Link: https://lore.kernel.org/linux-btrfs/CAJtFHUSy4zgyhf-4d9T+KdJp9w=UgzC2A0V=VtmaeEpcGgm1-Q@xxxxxxxxxxxxxx/
CC: stable@xxxxxxxxxxxxxxx # 5.4+
Reviewed-by: Anand Jain <anand.jain@xxxxxxxxxx>
Signed-off-by: Qu Wenruo <wqu@xxxxxxxx>
Reviewed-by: David Sterba <dsterba@xxxxxxxx>
Signed-off-by: David Sterba <dsterba@xxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/btrfs/space-info.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
--- a/fs/btrfs/space-info.c
+++ b/fs/btrfs/space-info.c
@@ -414,9 +414,10 @@ static void __btrfs_dump_space_info(stru
{
lockdep_assert_held(&info->lock);
- btrfs_info(fs_info, "space_info %llu has %llu free, is %sfull",
+ /* The free space could be negative in case of overcommit */
+ btrfs_info(fs_info, "space_info %llu has %lld free, is %sfull",
info->flags,
- info->total_bytes - btrfs_space_info_used(info, true),
+ (s64)(info->total_bytes - btrfs_space_info_used(info, true)),
info->full ? "" : "not ");
btrfs_info(fs_info,
"space_info total=%llu, used=%llu, pinned=%llu, reserved=%llu, may_use=%llu, readonly=%llu zone_unusable=%llu",
Patches currently in stable-queue which might be from wqu@xxxxxxxx are
queue-5.14/btrfs-prevent-__btrfs_dump_space_info-to-underflow-its-free-space.patch
