Messages in this thread | | | Date | Fri, 17 Jul 2015 19:31:17 +0200 | From | Oleg Nesterov <> | Subject | Re: [PATCH RFC 0/4] change sb_writers to use percpu_rw_semaphore |
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On 07/17, Dave Chinner wrote: > > On Thu, Jul 16, 2015 at 07:32:56PM +0200, Oleg Nesterov wrote: > > > > #ifdef CONFIG_LOCKDEP > > /* > > * We want lockdep to tell us about possible deadlocks with freezing but > > * it's it bit tricky to properly instrument it. Getting a freeze protection > > * works as getting a read lock but there are subtle problems. XFS for example > > * gets freeze protection on internal level twice in some cases, which is OK > > Sorry, I've missed something here - where is XFS nesting > sb_start_intwrite() calls?
Heh ;) I too tried to understand thi but failed. I was not surprized, I know nothing about fs/.
Dave, I didn't write this comment. Please look at acquire_freeze_lock(). If we can remove this logic - great! but this needs a separate change.
Oleg.
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