From 3c845acd0237caef617f330a0e3b37ad8ae9fea5 Mon Sep 17 00:00:00 2001
From: Jan Kara <jack@suse.cz>
Date: Fri, 15 Nov 2019 11:22:10 +0100
Subject: [PATCH] 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 <ebiggers@kernel.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20191115102210.29445-1-jack@suse.cz
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
---
include/linux/jbd2.h | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h
index 587c146d398780..842b62606025a5 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,
--
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