Merge branch 'for-linus-2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull the big VFS changes from Al Viro:
 "This one is *big* and changes quite a few things around VFS.  What's in there:

   - the first of two really major architecture changes - death to open
     intents.

     The former is finally there; it was very long in making, but with
     Miklos getting through really hard and messy final push in
     fs/namei.c, we finally have it.  Unlike his variant, this one
     doesn't introduce struct opendata; what we have instead is
     ->atomic_open() taking preallocated struct file * and passing
     everything via its fields.

     Instead of returning struct file *, it returns -E...  on error, 0
     on success and 1 in "deal with it yourself" case (e.g.  symlink
     found on server, etc.).

     See comments before fs/namei.c:atomic_open().  That made a lot of
     goodies finally possible and quite a few are in that pile:
     ->lookup(), ->d_revalidate() and ->create() do not get struct
     nameidata * anymore; ->lookup() and ->d_revalidate() get lookup
     flags instead, ->create() gets "do we want it exclusive" flag.

     With the introduction of new helper (kern_path_locked()) we are rid
     of all struct nameidata instances outside of fs/namei.c; it's still
     visible in namei.h, but not for long.  Come the next cycle,
     declaration will move either to fs/internal.h or to fs/namei.c
     itself.  [me, miklos, hch]

   - The second major change: behaviour of final fput().  Now we have
     __fput() done without any locks held by caller *and* not from deep
     in call stack.

     That obviously lifts a lot of constraints on the locking in there.
     Moreover, it's legal now to call fput() from atomic contexts (which
     has immediately simplified life for aio.c).  We also don't need
     anti-recursion logics in __scm_destroy() anymore.

     There is a price, though - the damn thing has become partially
     asynchronous.  For fput() from normal process we are guaranteed
     that pending __fput() will be done before the caller returns to
     userland, exits or gets stopped for ptrace.

     For kernel threads and atomic contexts it's done via
     schedule_work(), so theoretically we might need a way to make sure
     it's finished; so far only one such place had been found, but there
     might be more.

     There's flush_delayed_fput() (do all pending __fput()) and there's
     __fput_sync() (fput() analog doing __fput() immediately).  I hope
     we won't need them often; see warnings in fs/file_table.c for
     details.  [me, based on task_work series from Oleg merged last
     cycle]

   - sync series from Jan

   - large part of "death to sync_supers()" work from Artem; the only
     bits missing here are exofs and ext4 ones.  As far as I understand,
     those are going via the exofs and ext4 trees resp.; once they are
     in, we can put ->write_super() to the rest, along with the thread
     calling it.

   - preparatory bits from unionmount series (from dhowells).

   - assorted cleanups and fixes all over the place, as usual.

  This is not the last pile for this cycle; there's at least jlayton's
  ESTALE work and fsfreeze series (the latter - in dire need of fixes,
  so I'm not sure it'll make the cut this cycle).  I'll probably throw
  symlink/hardlink restrictions stuff from Kees into the next pile, too.
  Plus there's a lot of misc patches I hadn't thrown into that one -
  it's large enough as it is..."

* 'for-linus-2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (127 commits)
  ext4: switch EXT4_IOC_RESIZE_FS to mnt_want_write_file()
  btrfs: switch btrfs_ioctl_balance() to mnt_want_write_file()
  switch dentry_open() to struct path, make it grab references itself
  spufs: shift dget/mntget towards dentry_open()
  zoran: don't bother with struct file * in zoran_map
  ecryptfs: don't reinvent the wheels, please - use struct completion
  don't expose I_NEW inodes via dentry->d_inode
  tidy up namei.c a bit
  unobfuscate follow_up() a bit
  ext3: pass custom EOF to generic_file_llseek_size()
  ext4: use core vfs llseek code for dir seeks
  vfs: allow custom EOF in generic_file_llseek code
  vfs: Avoid unnecessary WB_SYNC_NONE writeback during sys_sync and reorder sync passes
  vfs: Remove unnecessary flushing of block devices
  vfs: Make sys_sync writeout also block device inodes
  vfs: Create function for iterating over block devices
  vfs: Reorder operations during sys_sync
  quota: Move quota syncing to ->sync_fs method
  quota: Split dquot_quota_sync() to writeback and cache flushing part
  vfs: Move noop_backing_dev_info check from sync into writeback
  ...

3 files changed, 5 insertions, 6 deletions

diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index ffd8900a38e..9292a8971e6 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -2157,8 +2157,7 @@ static inline void flush_unauthorized_files(const struct cred *cred,
 						get_file(devnull);
 					} else {
 						devnull = dentry_open(
-							dget(selinux_null),
-							mntget(selinuxfs_mount),
+							&selinux_null,
 							O_RDWR, cred);
 						if (IS_ERR(devnull)) {
 							devnull = NULL;
diff --git a/security/selinux/include/security.h b/security/selinux/include/security.h
index dde2005407a..6d3885165d1 100644
--- a/security/selinux/include/security.h
+++ b/security/selinux/include/security.h
@@ -221,7 +221,7 @@ extern void selinux_status_update_policyload(int seqno);
 extern void selinux_complete_init(void);
 extern int selinux_disable(void);
 extern void exit_sel_fs(void);
-extern struct dentry *selinux_null;
+extern struct path selinux_null;
 extern struct vfsmount *selinuxfs_mount;
 extern void selnl_notify_setenforce(int val);
 extern void selnl_notify_policyload(u32 seqno);
diff --git a/security/selinux/selinuxfs.c b/security/selinux/selinuxfs.c
index 3ad29025128..298e695d682 100644
--- a/security/selinux/selinuxfs.c
+++ b/security/selinux/selinuxfs.c
@@ -1297,7 +1297,7 @@ out:
 
 #define NULL_FILE_NAME "null"
 
-struct dentry *selinux_null;
+struct path selinux_null;
 
 static ssize_t sel_read_avc_cache_threshold(struct file *filp, char __user *buf,
 					    size_t count, loff_t *ppos)
@@ -1838,7 +1838,7 @@ static int sel_fill_super(struct super_block *sb, void *data, int silent)
 
 	init_special_inode(inode, S_IFCHR | S_IRUGO | S_IWUGO, MKDEV(MEM_MAJOR, 3));
 	d_add(dentry, inode);
-	selinux_null = dentry;
+	selinux_null.dentry = dentry;
 
 	dentry = sel_make_dir(sb->s_root, "avc", &sel_last_ino);
 	if (IS_ERR(dentry)) {
@@ -1912,7 +1912,7 @@ static int __init init_sel_fs(void)
 		return err;
 	}
 
-	selinuxfs_mount = kern_mount(&sel_fs_type);
+	selinux_null.mnt = selinuxfs_mount = kern_mount(&sel_fs_type);
 	if (IS_ERR(selinuxfs_mount)) {
 		printk(KERN_ERR "selinuxfs:  could not mount!\n");
 		err = PTR_ERR(selinuxfs_mount);