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
  ...

drivers/base/devtmpfs.c

@@ -227,33 +227,24 @@ static int handle_create(const char *nodename, umode_t mode, struct device *dev)
 
 static int dev_rmdir(const char *name)
 {
-	struct nameidata nd;
+	struct path parent;
 	struct dentry *dentry;
 	int err;
 
-	err = kern_path_parent(name, &nd);
-	if (err)
-		return err;
-
-	mutex_lock_nested(&nd.path.dentry->d_inode->i_mutex, I_MUTEX_PARENT);
-	dentry = lookup_one_len(nd.last.name, nd.path.dentry, nd.last.len);
-	if (!IS_ERR(dentry)) {
-		if (dentry->d_inode) {
-			if (dentry->d_inode->i_private == &thread)
-				err = vfs_rmdir(nd.path.dentry->d_inode,
-						dentry);
-			else
-				err = -EPERM;
-		} else {
-			err = -ENOENT;
-		}
-		dput(dentry);
+	dentry = kern_path_locked(name, &parent);
+	if (IS_ERR(dentry))
+		return PTR_ERR(dentry);
+	if (dentry->d_inode) {
+		if (dentry->d_inode->i_private == &thread)
+			err = vfs_rmdir(parent.dentry->d_inode, dentry);
+		else
+			err = -EPERM;
 	} else {
-		err = PTR_ERR(dentry);
+		err = -ENOENT;
 	}
-
-	mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
-	path_put(&nd.path);
+	dput(dentry);
+	mutex_unlock(&parent.dentry->d_inode->i_mutex);
+	path_put(&parent);
 	return err;
 }
 
@@ -305,50 +296,43 @@ static int dev_mynode(struct device *dev, struct inode *inode, struct kstat *sta
 
 static int handle_remove(const char *nodename, struct device *dev)
 {
-	struct nameidata nd;
+	struct path parent;
 	struct dentry *dentry;
-	struct kstat stat;
 	int deleted = 1;
 	int err;
 
-	err = kern_path_parent(nodename, &nd);
-	if (err)
-		return err;
+	dentry = kern_path_locked(nodename, &parent);
+	if (IS_ERR(dentry))
+		return PTR_ERR(dentry);
 
-	mutex_lock_nested(&nd.path.dentry->d_inode->i_mutex, I_MUTEX_PARENT);
-	dentry = lookup_one_len(nd.last.name, nd.path.dentry, nd.last.len);
-	if (!IS_ERR(dentry)) {
-		if (dentry->d_inode) {
-			err = vfs_getattr(nd.path.mnt, dentry, &stat);
-			if (!err && dev_mynode(dev, dentry->d_inode, &stat)) {
-				struct iattr newattrs;
-				/*
-				 * before unlinking this node, reset permissions
-				 * of possible references like hardlinks
-				 */
-				newattrs.ia_uid = 0;
-				newattrs.ia_gid = 0;
-				newattrs.ia_mode = stat.mode & ~0777;
-				newattrs.ia_valid =
-					ATTR_UID|ATTR_GID|ATTR_MODE;
-				mutex_lock(&dentry->d_inode->i_mutex);
-				notify_change(dentry, &newattrs);
-				mutex_unlock(&dentry->d_inode->i_mutex);
-				err = vfs_unlink(nd.path.dentry->d_inode,
-						 dentry);
-				if (!err || err == -ENOENT)
-					deleted = 1;
-			}
-		} else {
-			err = -ENOENT;
+	if (dentry->d_inode) {
+		struct kstat stat;
+		err = vfs_getattr(parent.mnt, dentry, &stat);
+		if (!err && dev_mynode(dev, dentry->d_inode, &stat)) {
+			struct iattr newattrs;
+			/*
+			 * before unlinking this node, reset permissions
+			 * of possible references like hardlinks
+			 */
+			newattrs.ia_uid = 0;
+			newattrs.ia_gid = 0;
+			newattrs.ia_mode = stat.mode & ~0777;
+			newattrs.ia_valid =
+				ATTR_UID|ATTR_GID|ATTR_MODE;
+			mutex_lock(&dentry->d_inode->i_mutex);
+			notify_change(dentry, &newattrs);
+			mutex_unlock(&dentry->d_inode->i_mutex);
+			err = vfs_unlink(parent.dentry->d_inode, dentry);
+			if (!err || err == -ENOENT)
+				deleted = 1;
 		}
-		dput(dentry);
 	} else {
-		err = PTR_ERR(dentry);
+		err = -ENOENT;
 	}
-	mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
+	dput(dentry);
+	mutex_unlock(&parent.dentry->d_inode->i_mutex);
 
-	path_put(&nd.path);
+	path_put(&parent);
 	if (deleted && strchr(nodename, '/'))
 		delete_path(nodename);
 	return err;