On copy up of regular file using an O_TMPFILE, lock upper dir only
before linking the tempfile in place.
Signed-off-by: NAmir Goldstein <amir73il@gmail.com>
Signed-off-by: NMiklos Szeredi <mszeredi@redhat.com>

Signed-off-by: NMiklos Szeredi <mszeredi@redhat.com>

Create the index dir on mount. The index dir will contain hardlinks to
upper inodes, named after the hex representation of their origin lower
inodes.

The index dir is going to be used to prevent breaking lower hardlinks
on copy up and to implement overlayfs NFS export.

Because the feature is not fully backward compat, enabling the feature
is opt-in by config/module/mount option.
Signed-off-by: NAmir Goldstein <amir73il@gmail.com>
Signed-off-by: NMiklos Szeredi <mszeredi@redhat.com>

Added an i_state flag I_INUSE and helpers to set/clear/test the bit.

The 'inuse' lock is an 'advisory' inode lock, that can be used to extend
exclusive create protection beyond parent->i_mutex lock among cooperating
users.

This is going to be used by overlayfs to get exclusive ownership on upper
and work dirs among overlayfs mounts.
Signed-off-by: NAmir Goldstein <amir73il@gmail.com>
Signed-off-by: NMiklos Szeredi <mszeredi@redhat.com>

Signed-off-by: NMiklos Szeredi <mszeredi@redhat.com>

Use the new ovl_inode mutex to synchonize concurrent copy up
instead of the super block copy up workqueue.

Moving the synchronization object from the overlay dentry to
the overlay inode is needed for synchonizing concurrent copy up
of lower hardlinks to the same upper inode.
Signed-off-by: NAmir Goldstein <amir73il@gmail.com>
Signed-off-by: NMiklos Szeredi <mszeredi@redhat.com>

Signed-off-by: NMiklos Szeredi <mszeredi@redhat.com>

Signed-off-by: NMiklos Szeredi <mszeredi@redhat.com>

Signed-off-by: NMiklos Szeredi <mszeredi@redhat.com>

Signed-off-by: NMiklos Szeredi <mszeredi@redhat.com>

Signed-off-by: NMiklos Szeredi <mszeredi@redhat.com>

An upper dir is marked "impure" to let ovl_iterate() know that this
directory may contain non pure upper entries whose d_ino may need to be
read from the origin inode.

We already mark a non-merge dir "impure" when moving a non-pure child
entry inside it, to let ovl_iterate() know not to iterate the non-merge
dir directly.

Mark also a merge dir "impure" when moving a non-pure child entry inside
it and when copying up a child entry inside it.

This can be used to optimize ovl_iterate() to perform a "pure merge" of
upper and lower directories, merging the content of the directories,
without having to read d_ino from origin inodes.
Signed-off-by: NAmir Goldstein <amir73il@gmail.com>
Signed-off-by: NMiklos Szeredi <mszeredi@redhat.com>

When moving a merge dir or non-dir with copy up origin into a non-merge
upper dir (a.k.a pure upper dir), we are marking the target parent dir
"impure". ovl_iterate() iterates pure upper dirs directly, because there is
no need to filter out whiteouts and merge dir content with lower dir. But
for the case of an "impure" upper dir, ovl_iterate() will not be able to
iterate the real upper dir directly, because it will need to lookup the
origin inode and use it to fill d_ino.
Signed-off-by: NAmir Goldstein <amir73il@gmail.com>
Signed-off-by: NMiklos Szeredi <mszeredi@redhat.com>

On failure to set opaque/redirect xattr on rename, skip setting xattr and
return -EXDEV.

On failure to set opaque xattr when creating a new directory, -EIO is
returned instead of -EOPNOTSUPP.

Any failure to set those xattr will be recorded in super block and
then setting any xattr on upper won't be attempted again.
Signed-off-by: NAmir Goldstein <amir73il@gmail.com>
Signed-off-by: NMiklos Szeredi <mszeredi@redhat.com>

xattr are needed by overlayfs for setting opaque dir, redirect dir
and copy up origin.

Check at mount time by trying to set the overlay.opaque xattr on the
workdir and if that fails issue a warning message.
Signed-off-by: NAmir Goldstein <amir73il@gmail.com>
Signed-off-by: NMiklos Szeredi <mszeredi@redhat.com>

For directory entries, non zero oe->numlower implies OVL_TYPE_MERGE.
Define a new type flag OVL_TYPE_ORIGIN to indicate that an entry holds a
reference to its lower copy up origin.

For directory entries ORIGIN := MERGE && UPPER. For non-dir entries ORIGIN
means that a lower type dentry has been recently copied up or that we were
able to find the copy up origin from overlay.origin xattr.
Signed-off-by: NAmir Goldstein <amir73il@gmail.com>
Signed-off-by: NMiklos Szeredi <mszeredi@redhat.com>

Some features can only work when all layers are on the same fs.  Test this
condition during mount time, so features can check them later.

Add helper ovl_same_sb() to return the common super block in case all
layers are on the same fs.
Signed-off-by: NAmir Goldstein <amir73il@gmail.com>
Signed-off-by: NMiklos Szeredi <mszeredi@redhat.com>

Prepare to mark sensitive kernel structures for randomization by making
sure they're using designated initializers. These were identified during
allyesconfig builds of x86, arm, and arm64, with most initializer fixes
extracted from grsecurity.

For these cases, use { }, which will be zero-filled, instead of
undesignated NULLs.
Signed-off-by: NKees Cook <keescook@chromium.org>
Signed-off-by: NMiklos Szeredi <mszeredi@redhat.com>

This removes the extra include header file that was added in commit
e58bc927 "Pull overlayfs updates from Miklos Szeredi" now that it
is no longer needed.

There are probably other such includes that got added during the
scheduler header splitup series, but this is the one that annoyed me
personally and I know about.
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Add #include <linux/cred.h> dependencies to all .c files rely on sched.h
doing that for them.

Note that even if the count where we need to add extra headers seems high,
it's still a net win, because <linux/sched.h> is included in over
2,200 files ...
Acked-by: NLinus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>

The overlay sb 'copyup_wq' and overlay inode 'copying' condition
variable are about to replace the upper sb rename_lock, as finer
grained synchronization objects for concurrent copy up.
Suggested-by: NMiklos Szeredi <miklos@szeredi.hu>
Signed-off-by: NAmir Goldstein <amir73il@gmail.com>
Signed-off-by: NMiklos Szeredi <mszeredi@redhat.com>

oe->opaque is set for

 a) whiteouts
 b) directories having the "trusted.overlay.opaque" xattr

Case b can be simplified, since setting the xattr always implies setting
oe->opaque.  Also once set, the opaque flag is never cleared.

Don't need to set opaque flag for non-directories.
Signed-off-by: NMiklos Szeredi <mszeredi@redhat.com>

Current code returns EXDEV when a directory would need to be copied up to
move.  We could copy up the directory tree in this case, but there's
another, simpler solution: point to old lower directory from moved upper
directory.

This is achieved with a "trusted.overlay.redirect" xattr storing the path
relative to the root of the overlay.  After such attribute has been set,
the directory can be moved without further actions required.

This is a backward incompatible feature, old kernels won't be able to
correctly mount an overlay containing redirected directories.
Signed-off-by: NMiklos Szeredi <mszeredi@redhat.com>

fs/overlayfs/super.c is the biggest of the overlayfs source files and it
contains various utility functions as well as the rather complicated lookup
code.  Split these parts out to separate files.

Before:

 1446 fs/overlayfs/super.c

After:

  919 fs/overlayfs/super.c
  267 fs/overlayfs/namei.c
  235 fs/overlayfs/util.c
   51 fs/overlayfs/ovl_entry.h
Signed-off-by: NMiklos Szeredi <mszeredi@redhat.com>