This is a note to let you know that I've just added the patch titled
btrfs: do not BUG_ON() on ENOMEM when dropping extent items for a range
to the 6.1-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-do-not-bug_on-on-enomem-when-dropping-extent-items-for-a-range.patch
and it can be found in the queue-6.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 162d053e15fe985f754ef495a96eb3db970c43ed Mon Sep 17 00:00:00 2001
From: Filipe Manana <fdmanana@xxxxxxxx>
Date: Mon, 28 Nov 2022 15:07:30 +0000
Subject: btrfs: do not BUG_ON() on ENOMEM when dropping extent items for a range
From: Filipe Manana <fdmanana@xxxxxxxx>
commit 162d053e15fe985f754ef495a96eb3db970c43ed upstream.
If we get -ENOMEM while dropping file extent items in a given range, at
btrfs_drop_extents(), due to failure to allocate memory when attempting to
increment the reference count for an extent or drop the reference count,
we handle it with a BUG_ON(). This is excessive, instead we can simply
abort the transaction and return the error to the caller. In fact most
callers of btrfs_drop_extents(), directly or indirectly, already abort
the transaction if btrfs_drop_extents() returns any error.
Also, we already have error paths at btrfs_drop_extents() that may return
-ENOMEM and in those cases we abort the transaction, like for example
anything that changes the b+tree may return -ENOMEM due to a failure to
allocate a new extent buffer when COWing an existing extent buffer, such
as a call to btrfs_duplicate_item() for example.
So replace the BUG_ON() calls with proper logic to abort the transaction
and return the error.
Reported-by: syzbot+0b1fb6b0108c27419f9f@xxxxxxxxxxxxxxxxxxxxxxxxx
Link: https://lore.kernel.org/linux-btrfs/00000000000089773e05ee4b9cb4@xxxxxxxxxx/
CC: stable@xxxxxxxxxxxxxxx # 5.4+
Reviewed-by: Josef Bacik <josef@xxxxxxxxxxxxxx>
Signed-off-by: Filipe Manana <fdmanana@xxxxxxxx>
Reviewed-by: David Sterba <dsterba@xxxxxxxx>
Signed-off-by: David Sterba <dsterba@xxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/btrfs/file.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -696,7 +696,10 @@ next_slot:
args->start - extent_offset,
0, false);
ret = btrfs_inc_extent_ref(trans, &ref);
- BUG_ON(ret); /* -ENOMEM */
+ if (ret) {
+ btrfs_abort_transaction(trans, ret);
+ break;
+ }
}
key.offset = args->start;
}
@@ -783,7 +786,10 @@ delete_extent_item:
key.offset - extent_offset, 0,
false);
ret = btrfs_free_extent(trans, &ref);
- BUG_ON(ret); /* -ENOMEM */
+ if (ret) {
+ btrfs_abort_transaction(trans, ret);
+ break;
+ }
args->bytes_found += extent_end - key.offset;
}
Patches currently in stable-queue which might be from fdmanana@xxxxxxxx are
queue-6.1/btrfs-do-not-bug_on-on-enomem-when-dropping-extent-items-for-a-range.patch
