6.1-stable review patch. If anyone has any objections, please let me know.
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From: Filipe Manana fdmanana@suse.com
commit 28cb13f29faf6290597b24b728dc3100c019356f upstream.
Instead of doing a BUG_ON() handle the error by returning -EUCLEAN, aborting the transaction and logging an error message.
Reviewed-by: Qu Wenruo wqu@suse.com Signed-off-by: Filipe Manana fdmanana@suse.com Signed-off-by: David Sterba dsterba@suse.com [Minor conflict resolved due to code context change.] Signed-off-by: Jianqi Ren jianqi.ren.cn@windriver.com Signed-off-by: He Zhe zhe.he@windriver.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/btrfs/extent-tree.c | 25 ++++++++++++++++++++----- 1 file changed, 20 insertions(+), 5 deletions(-)
--- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -179,6 +179,14 @@ search_again: ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item); num_refs = btrfs_extent_refs(leaf, ei); + if (unlikely(num_refs == 0)) { + ret = -EUCLEAN; + btrfs_err(fs_info, + "unexpected zero reference count for extent item (%llu %u %llu)", + key.objectid, key.type, key.offset); + btrfs_abort_transaction(trans, ret); + goto out_free; + } extent_flags = btrfs_extent_flags(leaf, ei); } else { ret = -EINVAL; @@ -190,8 +198,6 @@ search_again:
goto out_free; } - - BUG_ON(num_refs == 0); } else { num_refs = 0; extent_flags = 0; @@ -221,10 +227,19 @@ search_again: goto search_again; } spin_lock(&head->lock); - if (head->extent_op && head->extent_op->update_flags) + if (head->extent_op && head->extent_op->update_flags) { extent_flags |= head->extent_op->flags_to_set; - else - BUG_ON(num_refs == 0); + } else if (unlikely(num_refs == 0)) { + spin_unlock(&head->lock); + mutex_unlock(&head->mutex); + spin_unlock(&delayed_refs->lock); + ret = -EUCLEAN; + btrfs_err(fs_info, + "unexpected zero reference count for extent %llu (%s)", + bytenr, metadata ? "metadata" : "data"); + btrfs_abort_transaction(trans, ret); + goto out_free; + }
num_refs += head->ref_mod; spin_unlock(&head->lock);