On 08/04/2016 11:58 PM, Theodore Ts'o wrote: > 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. Is errors=continue the default option if nothing specifically is specified at mount time, since I don't have this set explicitly: /dev/vda / ext4 rw,relatime,data=ordered 0 0 > > 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 > -- 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
