From 3c845acd0237caef617f330a0e3b37ad8ae9fea5 Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Fri, 15 Nov 2019 11:22:10 +0100 Subject: jbd2: make jbd2_handle_buffer_credits() handle reserved handles The helper jbd2_handle_buffer_credits() doesn't correctly handle reserved handles which can lead to crashes. Fix it getting of journal pointer to work for reserved handles as well. Fixes: a9a8344ee171 ("ext4, jbd2: Provide accessor function for handle credits") Reported-by: Eric Biggers Signed-off-by: Jan Kara Link: https://lore.kernel.org/r/20191115102210.29445-1-jack@suse.cz Signed-off-by: Theodore Ts'o --- include/linux/jbd2.h | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) (limited to 'include/linux/jbd2.h') diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h index 587c146d3987..842b62606025 100644 --- a/include/linux/jbd2.h +++ b/include/linux/jbd2.h @@ -1627,10 +1627,14 @@ static inline tid_t jbd2_get_latest_transaction(journal_t *journal) return tid; } - static inline int jbd2_handle_buffer_credits(handle_t *handle) { - journal_t *journal = handle->h_transaction->t_journal; + journal_t *journal; + + if (!handle->h_reserved) + journal = handle->h_transaction->t_journal; + else + journal = handle->h_journal; return handle->h_total_credits - DIV_ROUND_UP(handle->h_revoke_credits_requested, -- cgit