Re: xfs_file_splice_read: possible circular locking dependency detected
Al Viro <[email protected]>
| Newsgroups | gmane.comp.file-systems.xfs.general |
|---|---|
| Message-ID | <[email protected]> |
On Fri, Sep 09, 2016 at 07:19:31AM +1000, Dave Chinner wrote: > Don't bother. You'll just hit a different lockdep issue - a locking > order problem on the write side. I tried to get that fixed years > ago: > > https://lkml.org/lkml/2011/7/18/4 > http://oss.sgi.com/archives/xfs/2011-08/msg00122.html > http://oss.sgi.com/archives/xfs/2012-11/msg00671.html > > That specific problem was fixed by the above write_iter > infrastructure fixes, but introduced the read side problem. i.e. > splice has /always/ had locking order issues that XFS exposed. Yep. I'll try to slap together something testable for the variant I'd outlined; I really think that the root of problems here is that we have parallel logics in ->read_iter and ->splice_read. That just might get rid of special-casing DAX in there, while we are at it... Looking at the DAX side of things, we need iov_iter_zero() to grok those as well (in addition to copy_page_to_iter() and copy_to_iter()). _______________________________________________ xfs mailing list [email protected] http://oss.sgi.com/mailman/listinfo/xfs