On Wed 20-01-21 16:20:01, Christoph Hellwig wrote: > On Wed, Jan 20, 2021 at 05:06:10PM +0100, Jan Kara wrote: > > Provide an address_space operation for filling pages needed for read > > into page cache. Filesystems can use this operation to seriealize > > page cache filling with e.g. hole punching properly. > > Besides the impending rewrite of the area - having another indirection > here is just horrible for performance. If we want locking in this area > it should be in core code and common for multiple file systems. This would mean pulling i_mmap_sem out from ext4/XFS/F2FS private inode into the VFS inode. Which is fine by me but it would grow struct inode for proc / tmpfs / btrfs (although for btrfs I'm not convinced it isn't actually prone to the race and doesn't need similar protection as xfs / ext4) so some people may object. Honza -- Jan Kara <jack@xxxxxxxx> SUSE Labs, CR
