6.8-stable review patch. If anyone has any objections, please let me know.
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From: Boris Burkov boris@bur.io
commit 211de93367304ab395357f8cb12568a4d1e20701 upstream.
The transaction is only able to free PERTRANS reservations for a root once that root has been recorded with the TRANS tag on the roots radix tree. Therefore, until we are sure that this root will get tagged, it isn't safe to convert. Generally, this is not an issue as *some* transaction will likely tag the root before long and this reservation will get freed in that transaction, but technically it could stick around until unmount and result in a warning about leaked metadata reservation space.
This path is most exercised by running the generic/269 fstest with CONFIG_BTRFS_DEBUG.
Fixes: a6496849671a ("btrfs: fix start transaction qgroup rsv double free") CC: stable@vger.kernel.org # 6.6+ Reviewed-by: Qu Wenruo wqu@suse.com Signed-off-by: Boris Burkov boris@bur.io Signed-off-by: David Sterba dsterba@suse.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/btrfs/transaction.c | 17 ++++++++--------- 1 file changed, 8 insertions(+), 9 deletions(-)
--- a/fs/btrfs/transaction.c +++ b/fs/btrfs/transaction.c @@ -747,14 +747,6 @@ again: h->reloc_reserved = reloc_reserved; }
- /* - * Now that we have found a transaction to be a part of, convert the - * qgroup reservation from prealloc to pertrans. A different transaction - * can't race in and free our pertrans out from under us. - */ - if (qgroup_reserved) - btrfs_qgroup_convert_reserved_meta(root, qgroup_reserved); - got_it: if (!current->journal_info) current->journal_info = h; @@ -788,8 +780,15 @@ got_it: * not just freed. */ btrfs_end_transaction(h); - return ERR_PTR(ret); + goto reserve_fail; } + /* + * Now that we have found a transaction to be a part of, convert the + * qgroup reservation from prealloc to pertrans. A different transaction + * can't race in and free our pertrans out from under us. + */ + if (qgroup_reserved) + btrfs_qgroup_convert_reserved_meta(root, qgroup_reserved);
return h;