On Thu, 2017-11-09 at 14:02 -0500, J . Bruce Fields wrote: > On Tue, Oct 17, 2017 at 07:44:17PM +0300, Amir Goldstein wrote: > > Miklos, > > > > This series implements NFS export support [3] and is based on > > two prep patch sets [1][2] posted earlier to overlayfs list. > > NFS export is enabled for overlayfs mount with the 'verify_dir' > > and 'index=all' mount options. > > > > The current implementation will copy up and index directories when > > directory file handles are encoded. Those extra copy ups could be > > avoided in the future. > > > > The current implementation does NOT support encoding connectable > > non-dir file handles for all overlay path types, so overlayfs should > > not be exported with the 'subtree_check' option. > > I hope this is not a show stopper for merging NFS export support? > > I'm not a big fan of subtree_check, and I'd be OK with filesystems > opting out of support for it. > > I'm not sure what to expect when you actually try to export overlayfs > with subtree_check. Does it fail on the export, or when clients first > try to access it, and what kind of error do you get? > As part of the NFS reexport series that I posted a couple of years ago, there was a set of patches that would make exportfs return a (sensible) error message when it tried to enable it on a filesystem that didn't support it. We could look at resurrecting that if there is interest in allowing filesystems to opt out of subtree checking. It wasn't terribly complex, IIRC. > > You'll notice that the series start by implementing naiive support > > for pure upper files export and later on, replaces the implementation > > of some of the operations. This may seem strange, but I found it > > convenient to progress slowly between testable mile stones and I find > > the series easier to review this way. Let me know if you want me to > > change the way that this series is organized to get rid of code that > > is later removed. > > > > To unit test overlayfs file handles, I enhanced xfstest open_by_handle > > test utility to encode/decode directories and check several other cases > > that were not covered by the original xfstest test. On my xfstests NFS > > export branch [4], there are two generic tests and one overlayfs specific > > test on the 'exportfs' group. > > > > I also ran the NFSTest nfstest_posix group on an exported overlayfs > > mount, but that test only creates pure upper files in overlay upper dir, > > so it is not much of a stress to the implementation. > > Might also be interesting to run some nfs tests in a loop while > restarting the server? > > --b. > > > > > Amir. > > > > [1] https://github.com/amir73il/linux/commits/ovl-verify-dir > > [2] https://github.com/amir73il/linux/commits/ovl-index-all > > [3] https://github.com/amir73il/linux/commits/ovl-nfs-export > > [4] https://github.com/amir73il/xfstests/commits/ovl-nfs-export > > > > Amir Goldstein (14): > > ovl: hash all overlay inodes for NFS export > > ovl: grab i_count reference of lower inode > > ovl: use d_splice_alias() in place of d_add() in lookup > > ovl: copy up of disconnected dentries > > ovl: encode/decode pure-upper non-connectable file handles > > ovl: encode pure-upper connectable file handles > > ovl: decode pure-upper connectable file handles > > ovl: encode/decode struct ovl_fh format file handles > > ovl: encode non-pure-upper non-connectable file handles > > ovl: obtain a non-pure-upper disconnected dentry > > ovl: decode non-pure-upper non-connectable file handles > > ovl: reconnect non-pure-upper dir file handles > > ovl: wire up NFS export support > > ovl: document NFS export > > > > Documentation/filesystems/overlayfs.txt | 61 +++++ > > fs/overlayfs/Makefile | 3 +- > > fs/overlayfs/copy_up.c | 74 ++++-- > > fs/overlayfs/export.c | 433 ++++++++++++++++++++++++++++++++ > > fs/overlayfs/inode.c | 23 +- > > fs/overlayfs/namei.c | 96 ++++--- > > fs/overlayfs/overlayfs.h | 32 ++- > > fs/overlayfs/super.c | 25 ++ > > fs/overlayfs/util.c | 13 +- > > 9 files changed, 678 insertions(+), 82 deletions(-) > > create mode 100644 fs/overlayfs/export.c > > > > -- > > 2.7.4 -- Jeff Layton <jlayton@xxxxxxxxxx> -- To unsubscribe from this list: send the line "unsubscribe linux-unionfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
