[PATCH v2 00/20] Overlayfs inodes index

[Amir Goldstein <amir73il@gmail.com>]

Miklos,

This set is an independent series a top of current overlayfs-next.
I yanked all the dependencies from previous postings (consistent d_ino,
dir_lock, verify_lower) and included everything needed in this posting.

This work introcuding the inodes index opt-in feature, which provides:
- Hardlinks are not broken on copy up
- Infrastructure for overlayfs NFS export

Hardlink copy up tests including concurrent copy up of lower hardlinks
are available on my xfstests dev branch [1].

There are some more TODO items before this is ready for v4.13, but I'd
love to hear what you think about the direction this has taken so far.

Thanks,
Amir.

TODO:
- Consistency of lower and upper hardlinks (*)
- Cleanup stale and orphan index entries on mount (**)
- Document the inodes index feature

(*) When any lower hardlink has been copied up, we get the indexed
    upper inode on lookup of all lower hardlinks and since they all
    share the same overlay inode, they have the same 'realinode'.
    Opening the lower hardlinks for read gives that lower inode
    and not the indexed upper 'realinode'. The tests in [1] demostrate
    this problem.
(**) A stale index entry has a missing or stale 'origin' xattr. An
     orphan index entry has nlink 1 and all lower hardlinks are covered.

v2:
- Rebase on top of overalyfs-next with all dependencies
- Remove 'verify_lower' dependency and simplify
- Lookup index dentry on ovl_lookup()
- Don't hash broken overlay hardlinks by origin
- Fix nlink count of overlay inodes
- Constant st_ino for indexed hardlinks

v1:
- Upper/work dir exclusive lock
- Introduce verify_lower mount option
- Hash overlay inodes by origin
- Introduce inodes index feature
- Copy up hardlinks using inodes index

[1] https://github.com/amir73il/xfstests/commits/overlayfs-devel

Amir Goldstein (20):
  vfs: introduce inode 'inuse' lock
  ovl: get exclusive ownership on upper/work dirs
  ovl: relax same fs constrain for ovl_check_origin()
  ovl: generalize ovl_create_workdir()
  ovl: introduce the inodes index dir feature
  ovl: verify upper root dir matches lower root dir
  ovl: verify index dir matches upper dir
  ovl: lookup index entry for non-dir
  ovl: move inode helpers to inode.c
  ovl: use ovl_inode_init() for initializing new inode
  ovl: hash overlay non-dir inodes by copy up origin inode
  ovl: fix nlink leak in ovl_rename()
  ovl: adjust overlay inode nlink for indexed inodes
  ovl: defer upper dir lock to tempfile link
  ovl: factor out ovl_copy_up_inode() helper
  ovl: generalize ovl_copy_up_locked() using actors
  ovl: generalize ovl_copy_up_one() using actors
  ovl: implement index dir copy up method
  ovl: handle race of concurrent lower hardlinks copy up
  ovl: constant inode number for hardlinks

 fs/inode.c               |  74 ++++++
 fs/overlayfs/Kconfig     |  20 ++
 fs/overlayfs/copy_up.c   | 648 ++++++++++++++++++++++++++++++++++++++---------
 fs/overlayfs/dir.c       |  23 +-
 fs/overlayfs/inode.c     | 138 +++++++++-
 fs/overlayfs/namei.c     | 241 +++++++++++++++---
 fs/overlayfs/overlayfs.h |  52 ++--
 fs/overlayfs/ovl_entry.h |   7 +
 fs/overlayfs/super.c     | 194 ++++++++++++--
 fs/overlayfs/util.c      |  45 ++--
 include/linux/fs.h       |  16 ++
 11 files changed, 1235 insertions(+), 223 deletions(-)

-- 
2.7.4