]> git.proxmox.com Git - mirror_ubuntu-eoan-kernel.git/commit
jbd: Fix assertion failure in fs/jbd/checkpoint.c
authorJan Kara <jack@suse.cz>
Wed, 5 Dec 2007 07:45:27 +0000 (23:45 -0800)
committerLinus Torvalds <torvalds@woody.linux-foundation.org>
Wed, 5 Dec 2007 17:21:20 +0000 (09:21 -0800)
commitd4beaf4ab5f89496f2bcf67db62ad95d99bfeff6
treeae6d005199017e9a0ade169fd69cb73d6c0ac88f
parent369b8f5a70402d9fe77006cd0044c8a3fcd08430
jbd: Fix assertion failure in fs/jbd/checkpoint.c

Before we start committing a transaction, we call
__journal_clean_checkpoint_list() to cleanup transaction's written-back
buffers.

If this call happens to remove all of them (and there were already some
buffers), __journal_remove_checkpoint() will decide to free the transaction
because it isn't (yet) a committing transaction and soon we fail some
assertion - the transaction really isn't ready to be freed :).

We change the check in __journal_remove_checkpoint() to free only a
transaction in T_FINISHED state.  The locking there is subtle though (as
everywhere in JBD ;().  We use j_list_lock to protect the check and a
subsequent call to __journal_drop_transaction() and do the same in the end
of journal_commit_transaction() which is the only place where a transaction
can get to T_FINISHED state.

Probably I'm too paranoid here and such locking is not really necessary -
checkpoint lists are processed only from log_do_checkpoint() where a
transaction must be already committed to be processed or from
__journal_clean_checkpoint_list() where kjournald itself calls it and thus
transaction cannot change state either.  Better be safe if something
changes in future...

Signed-off-by: Jan Kara <jack@suse.cz>
Cc: <linux-ext4@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
fs/jbd/checkpoint.c
fs/jbd/commit.c
include/linux/jbd.h