Am Mi., 17. Juni 2020 um 02:33 Uhr schrieb Matthew Wilcox <willy@xxxxxxxxxxxxx>:
>
> On Wed, Jun 17, 2020 at 12:36:13AM +0200, Andreas Gruenbacher wrote:
> > Am Mi., 15. Apr. 2020 um 23:39 Uhr schrieb Matthew Wilcox <willy@xxxxxxxxxxxxx>:
> > > From: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx>
> > >
> > > Implement the new readahead aop and convert all callers (block_dev,
> > > exfat, ext2, fat, gfs2, hpfs, isofs, jfs, nilfs2, ocfs2, omfs, qnx6,
> > > reiserfs & udf). The callers are all trivial except for GFS2 & OCFS2.
> >
> > This patch leads to an ABBA deadlock in xfstest generic/095 on gfs2.
> >
> > Our lock hierarchy is such that the inode cluster lock ("inode glock")
> > for an inode needs to be taken before any page locks in that inode's
> > address space.
>
> How does that work for ...
>
> writepage: yes, unlocks (see below)
> readpage: yes, unlocks
> invalidatepage: yes
> releasepage: yes
> freepage: yes
> isolate_page: yes
> migratepage: yes (both)
> putback_page: yes
> launder_page: yes
> is_partially_uptodate: yes
> error_remove_page: yes
>
> Is there a reason that you don't take the glock in the higher level
> ops which are called before readhead gets called? I'm looking at XFS,
> and it takes the xfs_ilock SHARED in xfs_file_buffered_aio_read()
> (called from xfs_file_read_iter).
Right, the approach from the following thread might fix this:
https://lore.kernel.org/linux-fsdevel/20191122235324.17245-1-agruenba@xxxxxxxxxx/T/#t
Andreas
