X-Git-Url: http://review.tizen.org/git/?a=blobdiff_plain;f=fs%2Fnamei.c;h=4bc4bc6a6938d4f6128e7a8dd1da2863e8021d91;hb=a8277b9baa6268de386529a33061775bc716198b;hp=c651f02c9fecb930c97a2668adc075090c04b7c9;hpb=40b46a7d2938589a5abab132a7824fd17ae18f62;p=platform%2Fadaptation%2Frenesas_rcar%2Frenesas_kernel.git

diff --git a/fs/namei.c b/fs/namei.c
index c651f02..4bc4bc6 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -449,7 +449,7 @@ static int unlazy_walk(struct nameidata *nd, struct dentry *dentry)
 	mntget(nd->path.mnt);
 
 	rcu_read_unlock();
-	br_read_unlock(vfsmount_lock);
+	br_read_unlock(&vfsmount_lock);
 	nd->flags &= ~LOOKUP_RCU;
 	return 0;
 
@@ -463,22 +463,6 @@ err_root:
 	return -ECHILD;
 }
 
-/**
- * release_open_intent - free up open intent resources
- * @nd: pointer to nameidata
- */
-void release_open_intent(struct nameidata *nd)
-{
-	struct file *file = nd->intent.open.file;
-
-	if (file && !IS_ERR(file)) {
-		if (file->f_path.dentry == NULL)
-			put_filp(file);
-		else
-			fput(file);
-	}
-}
-
 static inline int d_revalidate(struct dentry *dentry, struct nameidata *nd)
 {
 	return dentry->d_op->d_revalidate(dentry, nd);
@@ -507,14 +491,14 @@ static int complete_walk(struct nameidata *nd)
 		if (unlikely(!__d_rcu_to_refcount(dentry, nd->seq))) {
 			spin_unlock(&dentry->d_lock);
 			rcu_read_unlock();
-			br_read_unlock(vfsmount_lock);
+			br_read_unlock(&vfsmount_lock);
 			return -ECHILD;
 		}
 		BUG_ON(nd->inode != dentry->d_inode);
 		spin_unlock(&dentry->d_lock);
 		mntget(nd->path.mnt);
 		rcu_read_unlock();
-		br_read_unlock(vfsmount_lock);
+		br_read_unlock(&vfsmount_lock);
 	}
 
 	if (likely(!(nd->flags & LOOKUP_JUMPED)))
@@ -605,7 +589,7 @@ static inline void path_to_nameidata(const struct path *path,
 static inline void put_link(struct nameidata *nd, struct path *link, void *cookie)
 {
 	struct inode *inode = link->dentry->d_inode;
-	if (!IS_ERR(cookie) && inode->i_op->put_link)
+	if (inode->i_op->put_link)
 		inode->i_op->put_link(link->dentry, nd, cookie);
 	path_put(link);
 }
@@ -613,19 +597,19 @@ static inline void put_link(struct nameidata *nd, struct path *link, void *cooki
 static __always_inline int
 follow_link(struct path *link, struct nameidata *nd, void **p)
 {
-	int error;
 	struct dentry *dentry = link->dentry;
+	int error;
+	char *s;
 
 	BUG_ON(nd->flags & LOOKUP_RCU);
 
 	if (link->mnt == nd->path.mnt)
 		mntget(link->mnt);
 
-	if (unlikely(current->total_link_count >= 40)) {
-		*p = ERR_PTR(-ELOOP); /* no ->put_link(), please */
-		path_put(&nd->path);
-		return -ELOOP;
-	}
+	error = -ELOOP;
+	if (unlikely(current->total_link_count >= 40))
+		goto out_put_nd_path;
+
 	cond_resched();
 	current->total_link_count++;
 
@@ -633,30 +617,37 @@ follow_link(struct path *link, struct nameidata *nd, void **p)
 	nd_set_link(nd, NULL);
 
 	error = security_inode_follow_link(link->dentry, nd);
-	if (error) {
-		*p = ERR_PTR(error); /* no ->put_link(), please */
-		path_put(&nd->path);
-		return error;
-	}
+	if (error)
+		goto out_put_nd_path;
 
 	nd->last_type = LAST_BIND;
 	*p = dentry->d_inode->i_op->follow_link(dentry, nd);
 	error = PTR_ERR(*p);
-	if (!IS_ERR(*p)) {
-		char *s = nd_get_link(nd);
-		error = 0;
-		if (s)
-			error = __vfs_follow_link(nd, s);
-		else if (nd->last_type == LAST_BIND) {
-			nd->flags |= LOOKUP_JUMPED;
-			nd->inode = nd->path.dentry->d_inode;
-			if (nd->inode->i_op->follow_link) {
-				/* stepped on a _really_ weird one */
-				path_put(&nd->path);
-				error = -ELOOP;
-			}
+	if (IS_ERR(*p))
+		goto out_put_link;
+
+	error = 0;
+	s = nd_get_link(nd);
+	if (s) {
+		error = __vfs_follow_link(nd, s);
+	} else if (nd->last_type == LAST_BIND) {
+		nd->flags |= LOOKUP_JUMPED;
+		nd->inode = nd->path.dentry->d_inode;
+		if (nd->inode->i_op->follow_link) {
+			/* stepped on a _really_ weird one */
+			path_put(&nd->path);
+			error = -ELOOP;
 		}
 	}
+	if (unlikely(error))
+		put_link(nd, link, *p);
+
+	return error;
+
+out_put_nd_path:
+	path_put(&nd->path);
+out_put_link:
+	path_put(link);
 	return error;
 }
 
@@ -681,15 +672,15 @@ int follow_up(struct path *path)
 	struct mount *parent;
 	struct dentry *mountpoint;
 
-	br_read_lock(vfsmount_lock);
+	br_read_lock(&vfsmount_lock);
 	parent = mnt->mnt_parent;
 	if (&parent->mnt == path->mnt) {
-		br_read_unlock(vfsmount_lock);
+		br_read_unlock(&vfsmount_lock);
 		return 0;
 	}
 	mntget(&parent->mnt);
 	mountpoint = dget(mnt->mnt_mountpoint);
-	br_read_unlock(vfsmount_lock);
+	br_read_unlock(&vfsmount_lock);
 	dput(path->dentry);
 	path->dentry = mountpoint;
 	mntput(path->mnt);
@@ -947,7 +938,7 @@ failed:
 	if (!(nd->flags & LOOKUP_ROOT))
 		nd->root.mnt = NULL;
 	rcu_read_unlock();
-	br_read_unlock(vfsmount_lock);
+	br_read_unlock(&vfsmount_lock);
 	return -ECHILD;
 }
 
@@ -1125,8 +1116,8 @@ static struct dentry *__lookup_hash(struct qstr *name,
  *  small and for now I'd prefer to have fast path as straight as possible.
  *  It _is_ time-critical.
  */
-static int do_lookup(struct nameidata *nd, struct qstr *name,
-			struct path *path, struct inode **inode)
+static int lookup_fast(struct nameidata *nd, struct qstr *name,
+		       struct path *path, struct inode **inode)
 {
 	struct vfsmount *mnt = nd->path.mnt;
 	struct dentry *dentry, *parent = nd->path.dentry;
@@ -1208,7 +1199,7 @@ unlazy:
 			goto need_lookup;
 		}
 	}
-done:
+
 	path->mnt = mnt;
 	path->dentry = dentry;
 	err = follow_managed(path, nd->flags);
@@ -1222,6 +1213,17 @@ done:
 	return 0;
 
 need_lookup:
+	return 1;
+}
+
+/* Fast lookup failed, do it the slow way */
+static int lookup_slow(struct nameidata *nd, struct qstr *name,
+		       struct path *path)
+{
+	struct dentry *dentry, *parent;
+	int err;
+
+	parent = nd->path.dentry;
 	BUG_ON(nd->inode != parent->d_inode);
 
 	mutex_lock(&parent->d_inode->i_mutex);
@@ -1229,7 +1231,16 @@ need_lookup:
 	mutex_unlock(&parent->d_inode->i_mutex);
 	if (IS_ERR(dentry))
 		return PTR_ERR(dentry);
-	goto done;
+	path->mnt = nd->path.mnt;
+	path->dentry = dentry;
+	err = follow_managed(path, nd->flags);
+	if (unlikely(err < 0)) {
+		path_put_conditional(path, nd);
+		return err;
+	}
+	if (err)
+		nd->flags |= LOOKUP_JUMPED;
+	return 0;
 }
 
 static inline int may_lookup(struct nameidata *nd)
@@ -1265,7 +1276,7 @@ static void terminate_walk(struct nameidata *nd)
 		if (!(nd->flags & LOOKUP_ROOT))
 			nd->root.mnt = NULL;
 		rcu_read_unlock();
-		br_read_unlock(vfsmount_lock);
+		br_read_unlock(&vfsmount_lock);
 	}
 }
 
@@ -1301,21 +1312,26 @@ static inline int walk_component(struct nameidata *nd, struct path *path,
 	 */
 	if (unlikely(type != LAST_NORM))
 		return handle_dots(nd, type);
-	err = do_lookup(nd, name, path, &inode);
+	err = lookup_fast(nd, name, path, &inode);
 	if (unlikely(err)) {
-		terminate_walk(nd);
-		return err;
-	}
-	if (!inode) {
-		path_to_nameidata(path, nd);
-		terminate_walk(nd);
-		return -ENOENT;
+		if (err < 0)
+			goto out_err;
+
+		err = lookup_slow(nd, name, path);
+		if (err < 0)
+			goto out_err;
+
+		inode = path->dentry->d_inode;
 	}
+	err = -ENOENT;
+	if (!inode)
+		goto out_path_put;
+
 	if (should_follow_link(inode, follow)) {
 		if (nd->flags & LOOKUP_RCU) {
 			if (unlikely(unlazy_walk(nd, path->dentry))) {
-				terminate_walk(nd);
-				return -ECHILD;
+				err = -ECHILD;
+				goto out_err;
 			}
 		}
 		BUG_ON(inode != path->dentry->d_inode);
@@ -1324,6 +1340,12 @@ static inline int walk_component(struct nameidata *nd, struct path *path,
 	path_to_nameidata(path, nd);
 	nd->inode = inode;
 	return 0;
+
+out_path_put:
+	path_to_nameidata(path, nd);
+out_err:
+	terminate_walk(nd);
+	return err;
 }
 
 /*
@@ -1352,9 +1374,10 @@ static inline int nested_symlink(struct path *path, struct nameidata *nd)
 		void *cookie;
 
 		res = follow_link(&link, nd, &cookie);
-		if (!res)
-			res = walk_component(nd, path, &nd->last,
-					     nd->last_type, LOOKUP_FOLLOW);
+		if (res)
+			break;
+		res = walk_component(nd, path, &nd->last,
+				     nd->last_type, LOOKUP_FOLLOW);
 		put_link(nd, &link, cookie);
 	} while (res > 0);
 
@@ -1620,7 +1643,7 @@ static int path_init(int dfd, const char *name, unsigned int flags,
 		nd->path = nd->root;
 		nd->inode = inode;
 		if (flags & LOOKUP_RCU) {
-			br_read_lock(vfsmount_lock);
+			br_read_lock(&vfsmount_lock);
 			rcu_read_lock();
 			nd->seq = __read_seqcount_begin(&nd->path.dentry->d_seq);
 		} else {
@@ -1633,7 +1656,7 @@ static int path_init(int dfd, const char *name, unsigned int flags,
 
 	if (*name=='/') {
 		if (flags & LOOKUP_RCU) {
-			br_read_lock(vfsmount_lock);
+			br_read_lock(&vfsmount_lock);
 			rcu_read_lock();
 			set_root_rcu(nd);
 		} else {
@@ -1646,7 +1669,7 @@ static int path_init(int dfd, const char *name, unsigned int flags,
 			struct fs_struct *fs = current->fs;
 			unsigned seq;
 
-			br_read_lock(vfsmount_lock);
+			br_read_lock(&vfsmount_lock);
 			rcu_read_lock();
 
 			do {
@@ -1682,7 +1705,7 @@ static int path_init(int dfd, const char *name, unsigned int flags,
 			if (fput_needed)
 				*fp = file;
 			nd->seq = __read_seqcount_begin(&nd->path.dentry->d_seq);
-			br_read_lock(vfsmount_lock);
+			br_read_lock(&vfsmount_lock);
 			rcu_read_lock();
 		} else {
 			path_get(&file->f_path);
@@ -1746,8 +1769,9 @@ static int path_lookupat(int dfd, const char *name,
 			struct path link = path;
 			nd->flags |= LOOKUP_PARENT;
 			err = follow_link(&link, nd, &cookie);
-			if (!err)
-				err = lookup_last(nd, &path);
+			if (err)
+				break;
+			err = lookup_last(nd, &path);
 			put_link(nd, &link, cookie);
 		}
 	}
@@ -2156,19 +2180,261 @@ static inline int open_to_namei_flags(int flag)
 	return flag;
 }
 
+static int may_o_create(struct path *dir, struct dentry *dentry, umode_t mode)
+{
+	int error = security_path_mknod(dir, dentry, mode, 0);
+	if (error)
+		return error;
+
+	error = inode_permission(dir->dentry->d_inode, MAY_WRITE | MAY_EXEC);
+	if (error)
+		return error;
+
+	return security_inode_create(dir->dentry->d_inode, dentry, mode);
+}
+
+static struct file *atomic_open(struct nameidata *nd, struct dentry *dentry,
+				struct path *path, struct opendata *od,
+				const struct open_flags *op,
+				bool *want_write, bool need_lookup,
+				bool *created)
+{
+	struct inode *dir =  nd->path.dentry->d_inode;
+	unsigned open_flag = open_to_namei_flags(op->open_flag);
+	umode_t mode;
+	int error;
+	int acc_mode;
+	struct file *filp;
+	int create_error = 0;
+	struct dentry *const DENTRY_NOT_SET = (void *) -1UL;
+
+	BUG_ON(dentry->d_inode);
+
+	/* Don't create child dentry for a dead directory. */
+	if (unlikely(IS_DEADDIR(dir))) {
+		filp = ERR_PTR(-ENOENT);
+		goto out;
+	}
+
+	mode = op->mode & S_IALLUGO;
+	if ((open_flag & O_CREAT) && !IS_POSIXACL(dir))
+		mode &= ~current_umask();
+
+	if (open_flag & O_EXCL) {
+		open_flag &= ~O_TRUNC;
+		*created = true;
+	}
+
+	/*
+	 * Checking write permission is tricky, bacuse we don't know if we are
+	 * going to actually need it: O_CREAT opens should work as long as the
+	 * file exists.  But checking existence breaks atomicity.  The trick is
+	 * to check access and if not granted clear O_CREAT from the flags.
+	 *
+	 * Another problem is returing the "right" error value (e.g. for an
+	 * O_EXCL open we want to return EEXIST not EROFS).
+	 */
+	if ((open_flag & (O_CREAT | O_TRUNC)) ||
+	    (open_flag & O_ACCMODE) != O_RDONLY) {
+		error = mnt_want_write(nd->path.mnt);
+		if (!error) {
+			*want_write = true;
+		} else if (!(open_flag & O_CREAT)) {
+			/*
+			 * No O_CREATE -> atomicity not a requirement -> fall
+			 * back to lookup + open
+			 */
+			goto no_open;
+		} else if (open_flag & (O_EXCL | O_TRUNC)) {
+			/* Fall back and fail with the right error */
+			create_error = error;
+			goto no_open;
+		} else {
+			/* No side effects, safe to clear O_CREAT */
+			create_error = error;
+			open_flag &= ~O_CREAT;
+		}
+	}
+
+	if (open_flag & O_CREAT) {
+		error = may_o_create(&nd->path, dentry, op->mode);
+		if (error) {
+			create_error = error;
+			if (open_flag & O_EXCL)
+				goto no_open;
+			open_flag &= ~O_CREAT;
+		}
+	}
+
+	if (nd->flags & LOOKUP_DIRECTORY)
+		open_flag |= O_DIRECTORY;
+
+	od->dentry = DENTRY_NOT_SET;
+	od->mnt = nd->path.mnt;
+	filp = dir->i_op->atomic_open(dir, dentry, od, open_flag, mode,
+				      created);
+	if (IS_ERR(filp)) {
+		if (WARN_ON(od->dentry != DENTRY_NOT_SET))
+			dput(od->dentry);
+
+		if (create_error && PTR_ERR(filp) == -ENOENT)
+			filp = ERR_PTR(create_error);
+		goto out;
+	}
+
+	acc_mode = op->acc_mode;
+	if (*created) {
+		fsnotify_create(dir, dentry);
+		acc_mode = MAY_OPEN;
+	}
+
+	if (!filp) {
+		if (WARN_ON(od->dentry == DENTRY_NOT_SET)) {
+			filp = ERR_PTR(-EIO);
+			goto out;
+		}
+		if (od->dentry) {
+			dput(dentry);
+			dentry = od->dentry;
+		}
+		goto looked_up;
+	}
+
+	/*
+	 * We didn't have the inode before the open, so check open permission
+	 * here.
+	 */
+	error = may_open(&filp->f_path, acc_mode, open_flag);
+	if (error) {
+		fput(filp);
+		filp = ERR_PTR(error);
+	}
+
+out:
+	dput(dentry);
+	return filp;
+
+no_open:
+	if (need_lookup) {
+		dentry = lookup_real(dir, dentry, nd);
+		if (IS_ERR(dentry))
+			return ERR_CAST(dentry);
+
+		if (create_error) {
+			int open_flag = op->open_flag;
+
+			filp = ERR_PTR(create_error);
+			if ((open_flag & O_EXCL)) {
+				if (!dentry->d_inode)
+					goto out;
+			} else if (!dentry->d_inode) {
+				goto out;
+			} else if ((open_flag & O_TRUNC) &&
+				   S_ISREG(dentry->d_inode->i_mode)) {
+				goto out;
+			}
+			/* will fail later, go on to get the right error */
+		}
+	}
+looked_up:
+	path->dentry = dentry;
+	path->mnt = nd->path.mnt;
+	return NULL;
+}
+
+/*
+ * Lookup, maybe create and open the last component
+ *
+ * Must be called with i_mutex held on parent.
+ *
+ * Returns open file or NULL on success, error otherwise.  NULL means no open
+ * was performed, only lookup.
+ */
+static struct file *lookup_open(struct nameidata *nd, struct path *path,
+				struct opendata *od,
+				const struct open_flags *op,
+				bool *want_write, bool *created)
+{
+	struct dentry *dir = nd->path.dentry;
+	struct inode *dir_inode = dir->d_inode;
+	struct dentry *dentry;
+	int error;
+	bool need_lookup;
+
+	*created = false;
+	dentry = lookup_dcache(&nd->last, dir, nd, &need_lookup);
+	if (IS_ERR(dentry))
+		return ERR_CAST(dentry);
+
+	/* Cached positive dentry: will open in f_op->open */
+	if (!need_lookup && dentry->d_inode)
+		goto out_no_open;
+
+	if ((nd->flags & LOOKUP_OPEN) && dir_inode->i_op->atomic_open) {
+		return atomic_open(nd, dentry, path, od, op, want_write,
+				   need_lookup, created);
+	}
+
+	if (need_lookup) {
+		BUG_ON(dentry->d_inode);
+
+		dentry = lookup_real(dir_inode, dentry, nd);
+		if (IS_ERR(dentry))
+			return ERR_CAST(dentry);
+	}
+
+	/* Negative dentry, just create the file */
+	if (!dentry->d_inode && (op->open_flag & O_CREAT)) {
+		umode_t mode = op->mode;
+		if (!IS_POSIXACL(dir->d_inode))
+			mode &= ~current_umask();
+		/*
+		 * This write is needed to ensure that a
+		 * rw->ro transition does not occur between
+		 * the time when the file is created and when
+		 * a permanent write count is taken through
+		 * the 'struct file' in finish_open().
+		 */
+		error = mnt_want_write(nd->path.mnt);
+		if (error)
+			goto out_dput;
+		*want_write = true;
+		*created = true;
+		error = security_path_mknod(&nd->path, dentry, mode, 0);
+		if (error)
+			goto out_dput;
+		error = vfs_create(dir->d_inode, dentry, mode, nd);
+		if (error)
+			goto out_dput;
+	}
+out_no_open:
+	path->dentry = dentry;
+	path->mnt = nd->path.mnt;
+	return NULL;
+
+out_dput:
+	dput(dentry);
+	return ERR_PTR(error);
+}
+
 /*
  * Handle the last step of open()
  */
 static struct file *do_last(struct nameidata *nd, struct path *path,
-			    const struct open_flags *op, const char *pathname)
+			    struct opendata *od, const struct open_flags *op,
+			    const char *pathname)
 {
 	struct dentry *dir = nd->path.dentry;
-	struct dentry *dentry;
 	int open_flag = op->open_flag;
-	int will_truncate = open_flag & O_TRUNC;
-	int want_write = 0;
+	bool will_truncate = (open_flag & O_TRUNC) != 0;
+	bool want_write = false;
 	int acc_mode = op->acc_mode;
 	struct file *filp;
+	struct inode *inode;
+	bool created;
+	bool symlink_ok = false;
+	struct path save_parent = { .dentry = NULL, .mnt = NULL };
+	bool retried = false;
 	int error;
 
 	nd->flags &= ~LOOKUP_PARENT;
@@ -2190,107 +2456,87 @@ static struct file *do_last(struct nameidata *nd, struct path *path,
 			error = -EISDIR;
 			goto exit;
 		}
-		goto ok;
+		goto finish_open;
 	case LAST_BIND:
 		error = complete_walk(nd);
 		if (error)
 			return ERR_PTR(error);
 		audit_inode(pathname, dir);
-		goto ok;
+		goto finish_open;
 	}
 
 	if (!(open_flag & O_CREAT)) {
-		int symlink_ok = 0;
 		if (nd->last.name[nd->last.len])
 			nd->flags |= LOOKUP_FOLLOW | LOOKUP_DIRECTORY;
 		if (open_flag & O_PATH && !(nd->flags & LOOKUP_FOLLOW))
-			symlink_ok = 1;
+			symlink_ok = true;
 		/* we _can_ be in RCU mode here */
-		error = walk_component(nd, path, &nd->last, LAST_NORM,
-					!symlink_ok);
+		error = lookup_fast(nd, &nd->last, path, &inode);
+		if (likely(!error))
+			goto finish_lookup;
+
 		if (error < 0)
-			return ERR_PTR(error);
-		if (error) /* symlink */
-			return NULL;
-		/* sayonara */
+			goto exit;
+
+		BUG_ON(nd->inode != dir->d_inode);
+	} else {
+		/* create side of things */
+		/*
+		 * This will *only* deal with leaving RCU mode - LOOKUP_JUMPED
+		 * has been cleared when we got to the last component we are
+		 * about to look up
+		 */
 		error = complete_walk(nd);
 		if (error)
 			return ERR_PTR(error);
 
-		error = -ENOTDIR;
-		if (nd->flags & LOOKUP_DIRECTORY) {
-			if (!nd->inode->i_op->lookup)
-				goto exit;
-		}
-		audit_inode(pathname, nd->path.dentry);
-		goto ok;
+		audit_inode(pathname, dir);
+		error = -EISDIR;
+		/* trailing slashes? */
+		if (nd->last.name[nd->last.len])
+			goto exit;
 	}
 
-	/* create side of things */
-	/*
-	 * This will *only* deal with leaving RCU mode - LOOKUP_JUMPED has been
-	 * cleared when we got to the last component we are about to look up
-	 */
-	error = complete_walk(nd);
-	if (error)
-		return ERR_PTR(error);
+retry_lookup:
+	mutex_lock(&dir->d_inode->i_mutex);
+	filp = lookup_open(nd, path, od, op, &want_write, &created);
+	mutex_unlock(&dir->d_inode->i_mutex);
 
-	audit_inode(pathname, dir);
-	error = -EISDIR;
-	/* trailing slashes? */
-	if (nd->last.name[nd->last.len])
-		goto exit;
+	if (filp) {
+		if (IS_ERR(filp))
+			goto out;
 
-	mutex_lock(&dir->d_inode->i_mutex);
+		if (created || !S_ISREG(filp->f_path.dentry->d_inode->i_mode))
+			will_truncate = false;
 
-	dentry = lookup_hash(nd);
-	error = PTR_ERR(dentry);
-	if (IS_ERR(dentry)) {
-		mutex_unlock(&dir->d_inode->i_mutex);
-		goto exit;
+		audit_inode(pathname, filp->f_path.dentry);
+		goto opened;
 	}
 
-	path->dentry = dentry;
-	path->mnt = nd->path.mnt;
-
-	/* Negative dentry, just create the file */
-	if (!dentry->d_inode) {
-		umode_t mode = op->mode;
-		if (!IS_POSIXACL(dir->d_inode))
-			mode &= ~current_umask();
-		/*
-		 * This write is needed to ensure that a
-		 * rw->ro transition does not occur between
-		 * the time when the file is created and when
-		 * a permanent write count is taken through
-		 * the 'struct file' in nameidata_to_filp().
-		 */
-		error = mnt_want_write(nd->path.mnt);
-		if (error)
-			goto exit_mutex_unlock;
-		want_write = 1;
+	if (created) {
 		/* Don't check for write permission, don't truncate */
 		open_flag &= ~O_TRUNC;
-		will_truncate = 0;
+		will_truncate = false;
 		acc_mode = MAY_OPEN;
-		error = security_path_mknod(&nd->path, dentry, mode, 0);
-		if (error)
-			goto exit_mutex_unlock;
-		error = vfs_create(dir->d_inode, dentry, mode, nd);
-		if (error)
-			goto exit_mutex_unlock;
-		mutex_unlock(&dir->d_inode->i_mutex);
-		dput(nd->path.dentry);
-		nd->path.dentry = dentry;
-		goto common;
+		path_to_nameidata(path, nd);
+		goto finish_open_created;
 	}
 
 	/*
 	 * It already exists.
 	 */
-	mutex_unlock(&dir->d_inode->i_mutex);
 	audit_inode(pathname, path->dentry);
 
+	/*
+	 * If atomic_open() acquired write access it is dropped now due to
+	 * possible mount and symlink following (this might be optimized away if
+	 * necessary...)
+	 */
+	if (want_write) {
+		mnt_drop_write(nd->path.mnt);
+		want_write = false;
+	}
+
 	error = -EEXIST;
 	if (open_flag & O_EXCL)
 		goto exit_dput;
@@ -2302,84 +2548,132 @@ static struct file *do_last(struct nameidata *nd, struct path *path,
 	if (error)
 		nd->flags |= LOOKUP_JUMPED;
 
+	BUG_ON(nd->flags & LOOKUP_RCU);
+	inode = path->dentry->d_inode;
+finish_lookup:
+	/* we _can_ be in RCU mode here */
 	error = -ENOENT;
-	if (!path->dentry->d_inode)
-		goto exit_dput;
+	if (!inode) {
+		path_to_nameidata(path, nd);
+		goto exit;
+	}
 
-	if (path->dentry->d_inode->i_op->follow_link)
+	if (should_follow_link(inode, !symlink_ok)) {
+		if (nd->flags & LOOKUP_RCU) {
+			if (unlikely(unlazy_walk(nd, path->dentry))) {
+				error = -ECHILD;
+				goto exit;
+			}
+		}
+		BUG_ON(inode != path->dentry->d_inode);
 		return NULL;
+	}
 
-	path_to_nameidata(path, nd);
-	nd->inode = path->dentry->d_inode;
+	if ((nd->flags & LOOKUP_RCU) || nd->path.mnt != path->mnt) {
+		path_to_nameidata(path, nd);
+	} else {
+		save_parent.dentry = nd->path.dentry;
+		save_parent.mnt = mntget(path->mnt);
+		nd->path.dentry = path->dentry;
+
+	}
+	nd->inode = inode;
 	/* Why this, you ask?  _Now_ we might have grown LOOKUP_JUMPED... */
 	error = complete_walk(nd);
-	if (error)
+	if (error) {
+		path_put(&save_parent);
 		return ERR_PTR(error);
+	}
 	error = -EISDIR;
-	if (S_ISDIR(nd->inode->i_mode))
+	if ((open_flag & O_CREAT) && S_ISDIR(nd->inode->i_mode))
 		goto exit;
-ok:
+	error = -ENOTDIR;
+	if ((nd->flags & LOOKUP_DIRECTORY) && !nd->inode->i_op->lookup)
+		goto exit;
+	audit_inode(pathname, nd->path.dentry);
+finish_open:
 	if (!S_ISREG(nd->inode->i_mode))
-		will_truncate = 0;
+		will_truncate = false;
 
 	if (will_truncate) {
 		error = mnt_want_write(nd->path.mnt);
 		if (error)
 			goto exit;
-		want_write = 1;
+		want_write = true;
 	}
-common:
+finish_open_created:
 	error = may_open(&nd->path, acc_mode, open_flag);
 	if (error)
 		goto exit;
-	filp = nameidata_to_filp(nd);
-	if (!IS_ERR(filp)) {
-		error = ima_file_check(filp, op->acc_mode);
-		if (error) {
-			fput(filp);
-			filp = ERR_PTR(error);
-		}
+	od->mnt = nd->path.mnt;
+	filp = finish_open(od, nd->path.dentry, NULL);
+	if (IS_ERR(filp)) {
+		if (filp == ERR_PTR(-EOPENSTALE))
+			goto stale_open;
+		goto out;
 	}
-	if (!IS_ERR(filp)) {
-		if (will_truncate) {
-			error = handle_truncate(filp);
-			if (error) {
-				fput(filp);
-				filp = ERR_PTR(error);
-			}
-		}
+opened:
+	error = open_check_o_direct(filp);
+	if (error)
+		goto exit_fput;
+	error = ima_file_check(filp, op->acc_mode);
+	if (error)
+		goto exit_fput;
+
+	if (will_truncate) {
+		error = handle_truncate(filp);
+		if (error)
+			goto exit_fput;
 	}
 out:
 	if (want_write)
 		mnt_drop_write(nd->path.mnt);
-	path_put(&nd->path);
+	path_put(&save_parent);
+	terminate_walk(nd);
 	return filp;
 
-exit_mutex_unlock:
-	mutex_unlock(&dir->d_inode->i_mutex);
 exit_dput:
 	path_put_conditional(path, nd);
 exit:
 	filp = ERR_PTR(error);
 	goto out;
+exit_fput:
+	fput(filp);
+	goto exit;
+
+stale_open:
+	/* If no saved parent or already retried then can't retry */
+	if (!save_parent.dentry || retried)
+		goto out;
+
+	BUG_ON(save_parent.dentry != dir);
+	path_put(&nd->path);
+	nd->path = save_parent;
+	nd->inode = dir->d_inode;
+	save_parent.mnt = NULL;
+	save_parent.dentry = NULL;
+	if (want_write) {
+		mnt_drop_write(nd->path.mnt);
+		want_write = false;
+	}
+	retried = true;
+	goto retry_lookup;
 }
 
 static struct file *path_openat(int dfd, const char *pathname,
 		struct nameidata *nd, const struct open_flags *op, int flags)
 {
 	struct file *base = NULL;
-	struct file *filp;
+	struct opendata od;
+	struct file *res;
 	struct path path;
 	int error;
 
-	filp = get_empty_filp();
-	if (!filp)
+	od.filp = get_empty_filp();
+	if (!od.filp)
 		return ERR_PTR(-ENFILE);
 
-	filp->f_flags = op->open_flag;
-	nd->intent.open.file = filp;
-	nd->intent.open.flags = open_to_namei_flags(op->open_flag);
-	nd->intent.open.create_mode = op->mode;
+	od.filp->f_flags = op->open_flag;
 
 	error = path_init(dfd, pathname, flags | LOOKUP_PARENT, nd, &base);
 	if (unlikely(error))
@@ -2390,23 +2684,22 @@ static struct file *path_openat(int dfd, const char *pathname,
 	if (unlikely(error))
 		goto out_filp;
 
-	filp = do_last(nd, &path, op, pathname);
-	while (unlikely(!filp)) { /* trailing symlink */
+	res = do_last(nd, &path, &od, op, pathname);
+	while (unlikely(!res)) { /* trailing symlink */
 		struct path link = path;
 		void *cookie;
 		if (!(nd->flags & LOOKUP_FOLLOW)) {
 			path_put_conditional(&path, nd);
 			path_put(&nd->path);
-			filp = ERR_PTR(-ELOOP);
+			res = ERR_PTR(-ELOOP);
 			break;
 		}
 		nd->flags |= LOOKUP_PARENT;
 		nd->flags &= ~(LOOKUP_OPEN|LOOKUP_CREATE|LOOKUP_EXCL);
 		error = follow_link(&link, nd, &cookie);
 		if (unlikely(error))
-			filp = ERR_PTR(error);
-		else
-			filp = do_last(nd, &path, op, pathname);
+			goto out_filp;
+		res = do_last(nd, &path, &od, op, pathname);
 		put_link(nd, &link, cookie);
 	}
 out:
@@ -2414,11 +2707,20 @@ out:
 		path_put(&nd->root);
 	if (base)
 		fput(base);
-	release_open_intent(nd);
-	return filp;
+	if (od.filp) {
+		BUG_ON(od.filp->f_path.dentry);
+		put_filp(od.filp);
+	}
+	if (res == ERR_PTR(-EOPENSTALE)) {
+		if (flags & LOOKUP_RCU)
+			res = ERR_PTR(-ECHILD);
+		else
+			res = ERR_PTR(-ESTALE);
+	}
+	return res;
 
 out_filp:
-	filp = ERR_PTR(error);
+	res = ERR_PTR(error);
 	goto out;
 }
 
@@ -2474,7 +2776,6 @@ struct dentry *kern_path_create(int dfd, const char *pathname, struct path *path
 		goto out;
 	nd.flags &= ~LOOKUP_PARENT;
 	nd.flags |= LOOKUP_CREATE | LOOKUP_EXCL;
-	nd.intent.open.flags = O_EXCL;
 
 	/*
 	 * Do the final lookup.