Re: [PATCH 0/4] Properly invalidate data in the cleancache.

From: Konrad Rzeszutek Wilk
Date: Tue Apr 18 2017 - 11:25:22 EST


On Fri, Apr 14, 2017 at 05:07:49PM +0300, Andrey Ryabinin wrote:
> We've noticed that after direct IO write, buffered read sometimes gets
> stale data which is coming from the cleancache.

That is not good.
> The reason for this is that some direct write hooks call call invalidate_inode_pages2[_range]()
> conditionally iff mapping->nrpages is not zero, so we may not invalidate
> data in the cleancache.
>
> Another odd thing is that we check only for ->nrpages and don't check for ->nrexceptional,

Yikes.
> but invalidate_inode_pages2[_range] also invalidates exceptional entries as well.
> So we invalidate exceptional entries only if ->nrpages != 0? This doesn't feel right.
>
> - Patch 1 fixes direct IO writes by removing ->nrpages check.
> - Patch 2 fixes similar case in invalidate_bdev().
> Note: I only fixed conditional cleancache_invalidate_inode() here.
> Do we also need to add ->nrexceptional check in into invalidate_bdev()?
>
> - Patches 3-4: some optimizations.

Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>

Thanks!
>
> Andrey Ryabinin (4):
> fs: fix data invalidation in the cleancache during direct IO
> fs/block_dev: always invalidate cleancache in invalidate_bdev()
> mm/truncate: bail out early from invalidate_inode_pages2_range() if
> mapping is empty
> mm/truncate: avoid pointless cleancache_invalidate_inode() calls.
>
> fs/9p/vfs_file.c | 2 +-
> fs/block_dev.c | 11 +++++------
> fs/cifs/inode.c | 2 +-
> fs/dax.c | 2 +-
> fs/iomap.c | 16 +++++++---------
> fs/nfs/direct.c | 6 ++----
> fs/nfs/inode.c | 8 +++++---
> mm/filemap.c | 26 +++++++++++---------------
> mm/truncate.c | 13 +++++++++----
> 9 files changed, 42 insertions(+), 44 deletions(-)
>
> --
> 2.10.2
>