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). Not that after -rc1 is a great time to be upending the locking model in a filesystem ... but then, this has been baking in -mm for ten weeks and the GFS2 mailing list has been on the cc for the patches for five months, so I don't have a lot of sympathy for this.