On Mon, 2019-02-04 at 15:31 -0500, Benjamin Coddington wrote: > On 4 Feb 2019, at 14:20, Benjamin Coddington wrote: > > > On 4 Feb 2019, at 14:07, Benjamin Coddington wrote: > > > > > On 4 Feb 2019, at 14:03, Benjamin Coddington wrote: > > > > > > > On 4 Feb 2019, at 13:32, Trond Myklebust wrote: > > > > > > > > > On Mon, 2019-02-04 at 13:13 -0500, Benjamin Coddington wrote: > > > > > > If nfs_page_async_flush() removes the page from the > > > > > > mapping, then we > > > > > > can't use page_file_mapping() on it as nfs_updatepate() is > > > > > > wont to do > > > > > > when receiving an error. Instead, simplify > > > > > > nfs_zap_mapping() to take > > > > > > the inode. > > > > > > > > > > > > > > > > Won't this break NFS swap? > > > > > > > > I guess it may, but then I wonder: is that a thing that anyone > > > > does? It > > > > sounds like a terrible idea.. > > > > > > > > I'm curious enough though, and doing some research on it. > > > > > > There's enough to commits in the tree fixing problem or > > > supporting swap > > > on NFS, so I suppose I've just missed all that. > > > > So for diskless systems, ah. It makes sense. > > > > But does it make any sense to set NFS_INO_INVALID_DATA on a swap > > file? > > Does anyone share them? > > > > Dazed and confused, but trying to continue.. > > So if the page is backing a swap file, nfs_zap_mapping() will fail to > set > NFS_INO_INVALID_DATA because i_mapping.nrpages will always be 0. > > But it looks like NFS has already decided to not care if the mapping > needs > revalidation for swap, since we assume /shared/ swap files are > insane. > > So without testing swap on NFS at all, it seems safe. > What about the case when the page is in the swap cache? Is that also safe? -- Trond Myklebust Linux NFS client maintainer, Hammerspace trond.myklebust@xxxxxxxxxxxxxxx
