From 162d053e15fe985f754ef495a96eb3db970c43ed Mon Sep 17 00:00:00 2001 From: Filipe Manana Date: Mon, 28 Nov 2022 15:07:30 +0000 Subject: btrfs: do not BUG_ON() on ENOMEM when dropping extent items for a range 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@syzkaller.appspotmail.com Link: https://lore.kernel.org/linux-btrfs/00000000000089773e05ee4b9cb4@google.com/ CC: stable@vger.kernel.org # 5.4+ Reviewed-by: Josef Bacik Signed-off-by: Filipe Manana Reviewed-by: David Sterba Signed-off-by: David Sterba --- fs/btrfs/file.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) (limited to 'fs/btrfs/file.c') diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c index 448b143a5cb2..91b00eb2440e 100644 --- a/fs/btrfs/file.c +++ b/fs/btrfs/file.c @@ -380,7 +380,10 @@ 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; } @@ -467,7 +470,10 @@ 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; } -- cgit