On Thu, Aug 04, 2016 at 06:05:50PM +0200, Jan Kara wrote: > On Wed 03-08-16 10:22:03, Nikolay Borisov wrote: > > While doing some testing on today's checkout of Linus' master branch I > > got the following: > > > > > [ 9.302725] BUG: sleeping function called from invalid context at ./include/linux/buffer_head.h:358 > > [ 9.304403] in_atomic(): 1, irqs_disabled(): 0, pid: 1718, name: mount > > [ 9.305633] 8 locks held by mount/1718: > > Yeah, this looks like a regression cause by commit 4743f83990614af "ext4: > Fix WARN_ON_ONCE in ext4_commit_super()". Arguably that cure is worse than > the disease but OTOH calling ext4_commit_super() from an atomic context > (like __ext4_grp_locked_error() does) sucks as well. > > I'm not sure what the right fix is here. The cleanest would probably be to > always drop group lock in __ext4_grp_locked_error() and make sure we always > properly bail out of mballoc code on such error. But that's a non-trivial > amount of work. Not sure if other ext4 people have opinion on this? The easist way to fix this is defer the ext4_commit_super() to a workqueue. We only need this in the errors=continue case, and in that scenario we're not in a hurry when the superblock gets written out. In fact, we probably want to be doing this for all of the errors=continue cases when we want to save the error state to the superblock, so we can do the update properly using the journal, instead of calling ext4_commit_super() which just force writes the block. (Of course, if the journal is aborted we'll need to fall back to using ext4_commit_super, of course.) - Ted -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
