The patch below does not apply to the 4.4-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@xxxxxxxxxxxxxxx>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From 867ed321f90d06aaba84e2c91de51cd3038825ef Mon Sep 17 00:00:00 2001
From: Josef Bacik <josef@xxxxxxxxxxxxxx>
Date: Thu, 14 Jan 2021 14:02:46 -0500
Subject: [PATCH] btrfs: abort the transaction if we fail to inc ref in
btrfs_copy_root
While testing my error handling patches, I added a error injection site
at btrfs_inc_extent_ref, to validate the error handling I added was
doing the correct thing. However I hit a pretty ugly corruption while
doing this check, with the following error injection stack trace:
btrfs_inc_extent_ref
btrfs_copy_root
create_reloc_root
btrfs_init_reloc_root
btrfs_record_root_in_trans
btrfs_start_transaction
btrfs_update_inode
btrfs_update_time
touch_atime
file_accessed
btrfs_file_mmap
This is because we do not catch the error from btrfs_inc_extent_ref,
which in practice would be ENOMEM, which means we lose the extent
references for a root that has already been allocated and inserted,
which is the problem. Fix this by aborting the transaction if we fail
to do the reference modification.
CC: stable@xxxxxxxxxxxxxxx # 4.4+
Signed-off-by: Josef Bacik <josef@xxxxxxxxxxxxxx>
Reviewed-by: David Sterba <dsterba@xxxxxxxx>
Signed-off-by: David Sterba <dsterba@xxxxxxxx>
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index 56e132d825a2..95d9bae764ab 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -221,9 +221,10 @@ int btrfs_copy_root(struct btrfs_trans_handle *trans,
ret = btrfs_inc_ref(trans, root, cow, 1);
else
ret = btrfs_inc_ref(trans, root, cow, 0);
-
- if (ret)
+ if (ret) {
+ btrfs_abort_transaction(trans, ret);
return ret;
+ }
btrfs_mark_buffer_dirty(cow);
*cow_ret = cow;
