1 files changed, 65 insertions, 146 deletions

diff --git a/fs/open.c b/fs/open.c
index 1540632..1e914b3 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -537,25 +537,6 @@ static int chown_common(struct path *path, uid_t user, gid_t group)
 	return error;
 }
 
-SYSCALL_DEFINE3(chown, const char __user *, filename, uid_t, user, gid_t, group)
-{
-	struct path path;
-	int error;
-
-	error = user_path(filename, &path);
-	if (error)
-		goto out;
-	error = mnt_want_write(path.mnt);
-	if (error)
-		goto out_release;
-	error = chown_common(&path, user, group);
-	mnt_drop_write(path.mnt);
-out_release:
-	path_put(&path);
-out:
-	return error;
-}
-
 SYSCALL_DEFINE5(fchownat, int, dfd, const char __user *, filename, uid_t, user,
 		gid_t, group, int, flag)
 {
@@ -583,23 +564,15 @@ out:
 	return error;
 }
 
-SYSCALL_DEFINE3(lchown, const char __user *, filename, uid_t, user, gid_t, group)
+SYSCALL_DEFINE3(chown, const char __user *, filename, uid_t, user, gid_t, group)
 {
-	struct path path;
-	int error;
+	return sys_fchownat(AT_FDCWD, filename, user, group, 0);
+}
 
-	error = user_lpath(filename, &path);
-	if (error)
-		goto out;
-	error = mnt_want_write(path.mnt);
-	if (error)
-		goto out_release;
-	error = chown_common(&path, user, group);
-	mnt_drop_write(path.mnt);
-out_release:
-	path_put(&path);
-out:
-	return error;
+SYSCALL_DEFINE3(lchown, const char __user *, filename, uid_t, user, gid_t, group)
+{
+	return sys_fchownat(AT_FDCWD, filename, user, group,
+			    AT_SYMLINK_NOFOLLOW);
 }
 
 SYSCALL_DEFINE3(fchown, unsigned int, fd, uid_t, user, gid_t, group)
@@ -667,10 +640,9 @@ int open_check_o_direct(struct file *f)
 	return 0;
 }
 
-static struct file *do_dentry_open(struct dentry *dentry, struct vfsmount *mnt,
-				   struct file *f,
-				   int (*open)(struct inode *, struct file *),
-				   const struct cred *cred)
+static int do_dentry_open(struct file *f,
+			  int (*open)(struct inode *, struct file *),
+			  const struct cred *cred)
 {
 	static const struct file_operations empty_fops = {};
 	struct inode *inode;
@@ -682,9 +654,9 @@ static struct file *do_dentry_open(struct dentry *dentry, struct vfsmount *mnt,
 	if (unlikely(f->f_flags & O_PATH))
 		f->f_mode = FMODE_PATH;
 
-	inode = dentry->d_inode;
+	inode = f->f_path.dentry->d_inode;
 	if (f->f_mode & FMODE_WRITE) {
-		error = __get_file_write_access(inode, mnt);
+		error = __get_file_write_access(inode, f->f_path.mnt);
 		if (error)
 			goto cleanup_file;
 		if (!special_file(inode->i_mode))
@@ -692,14 +664,12 @@ static struct file *do_dentry_open(struct dentry *dentry, struct vfsmount *mnt,
 	}
 
 	f->f_mapping = inode->i_mapping;
-	f->f_path.dentry = dentry;
-	f->f_path.mnt = mnt;
 	f->f_pos = 0;
 	file_sb_list_add(f, inode->i_sb);
 
 	if (unlikely(f->f_mode & FMODE_PATH)) {
 		f->f_op = &empty_fops;
-		return f;
+		return 0;
 	}
 
 	f->f_op = fops_get(inode->i_fop);
@@ -726,10 +696,11 @@ static struct file *do_dentry_open(struct dentry *dentry, struct vfsmount *mnt,
 
 	file_ra_state_init(&f->f_ra, f->f_mapping->host->i_mapping);
 
-	return f;
+	return 0;
 
 cleanup_all:
 	fops_put(f->f_op);
+	file_sb_list_del(f);
 	if (f->f_mode & FMODE_WRITE) {
 		put_write_access(inode);
 		if (!special_file(inode->i_mode)) {
@@ -740,124 +711,62 @@ cleanup_all:
 			 * here, so just reset the state.
 			 */
 			file_reset_write(f);
-			mnt_drop_write(mnt);
+			mnt_drop_write(f->f_path.mnt);
 		}
 	}
-	file_sb_list_del(f);
-	f->f_path.dentry = NULL;
-	f->f_path.mnt = NULL;
 cleanup_file:
-	dput(dentry);
-	mntput(mnt);
-	return ERR_PTR(error);
-}
-
-static struct file *__dentry_open(struct dentry *dentry, struct vfsmount *mnt,
-				struct file *f,
-				int (*open)(struct inode *, struct file *),
-				const struct cred *cred)
-{
-	struct file *res = do_dentry_open(dentry, mnt, f, open, cred);
-	if (!IS_ERR(res)) {
-		int error = open_check_o_direct(f);
-		if (error) {
-			fput(res);
-			res = ERR_PTR(error);
-		}
-	} else {
-		put_filp(f);
-	}
-	return res;
+	path_put(&f->f_path);
+	f->f_path.mnt = NULL;
+	f->f_path.dentry = NULL;
+	return error;
 }
 
 /**
- * lookup_instantiate_filp - instantiates the open intent filp
- * @nd: pointer to nameidata
+ * finish_open - finish opening a file
+ * @od: opaque open data
  * @dentry: pointer to dentry
  * @open: open callback
  *
- * Helper for filesystems that want to use lookup open intents and pass back
- * a fully instantiated struct file to the caller.
- * This function is meant to be called from within a filesystem's
- * lookup method.
- * Beware of calling it for non-regular files! Those ->open methods might block
- * (e.g. in fifo_open), leaving you with parent locked (and in case of fifo,
- * leading to a deadlock, as nobody can open that fifo anymore, because
- * another process to open fifo will block on locked parent when doing lookup).
- * Note that in case of error, nd->intent.open.file is destroyed, but the
- * path information remains valid.
+ * This can be used to finish opening a file passed to i_op->atomic_open().
+ *
  * If the open callback is set to NULL, then the standard f_op->open()
  * filesystem callback is substituted.
  */
-struct file *lookup_instantiate_filp(struct nameidata *nd, struct dentry *dentry,
-		int (*open)(struct inode *, struct file *))
+int finish_open(struct file *file, struct dentry *dentry,
+		int (*open)(struct inode *, struct file *),
+		int *opened)
 {
-	const struct cred *cred = current_cred();
+	int error;
+	BUG_ON(*opened & FILE_OPENED); /* once it's opened, it's opened */
 
-	if (IS_ERR(nd->intent.open.file))
-		goto out;
-	if (IS_ERR(dentry))
-		goto out_err;
-	nd->intent.open.file = __dentry_open(dget(dentry), mntget(nd->path.mnt),
-					     nd->intent.open.file,
-					     open, cred);
-out:
-	return nd->intent.open.file;
-out_err:
-	release_open_intent(nd);
-	nd->intent.open.file = ERR_CAST(dentry);
-	goto out;
+	mntget(file->f_path.mnt);
+	file->f_path.dentry = dget(dentry);
+
+	error = do_dentry_open(file, open, current_cred());
+	if (!error)
+		*opened |= FILE_OPENED;
+
+	return error;
 }
-EXPORT_SYMBOL_GPL(lookup_instantiate_filp);
+EXPORT_SYMBOL(finish_open);
 
 /**
- * nameidata_to_filp - convert a nameidata to an open filp.
- * @nd: pointer to nameidata
- * @flags: open flags
+ * finish_no_open - finish ->atomic_open() without opening the file
+ *
+ * @od: opaque open data
+ * @dentry: dentry or NULL (as returned from ->lookup())
  *
- * Note that this function destroys the original nameidata
+ * This can be used to set the result of a successful lookup in ->atomic_open().
+ * The filesystem's atomic_open() method shall return NULL after calling this.
  */
-struct file *nameidata_to_filp(struct nameidata *nd)
+int finish_no_open(struct file *file, struct dentry *dentry)
 {
-	const struct cred *cred = current_cred();
-	struct file *filp;
-
-	/* Pick up the filp from the open intent */
-	filp = nd->intent.open.file;
-
-	/* Has the filesystem initialised the file for us? */
-	if (filp->f_path.dentry != NULL) {
-		nd->intent.open.file = NULL;
-	} else {
-		struct file *res;
-
-		path_get(&nd->path);
-		res = do_dentry_open(nd->path.dentry, nd->path.mnt,
-				     filp, NULL, cred);
-		if (!IS_ERR(res)) {
-			int error;
-
-			nd->intent.open.file = NULL;
-			BUG_ON(res != filp);
-
-			error = open_check_o_direct(filp);
-			if (error) {
-				fput(filp);
-				filp = ERR_PTR(error);
-			}
-		} else {
-			/* Allow nd->intent.open.file to be recycled */
-			filp = res;
-		}
-	}
-	return filp;
+	file->f_path.dentry = dentry;
+	return 1;
 }
+EXPORT_SYMBOL(finish_no_open);
 
-/*
- * dentry_open() will have done dput(dentry) and mntput(mnt) if it returns an
- * error.
- */
-struct file *dentry_open(struct dentry *dentry, struct vfsmount *mnt, int flags,
+struct file *dentry_open(const struct path *path, int flags,
 			 const struct cred *cred)
 {
 	int error;
@@ -866,18 +775,28 @@ struct file *dentry_open(struct dentry *dentry, struct vfsmount *mnt, int flags,
 	validate_creds(cred);
 
 	/* We must always pass in a valid mount pointer. */
-	BUG_ON(!mnt);
+	BUG_ON(!path->mnt);
 
 	error = -ENFILE;
 	f = get_empty_filp();
-	if (f == NULL) {
-		dput(dentry);
-		mntput(mnt);
+	if (f == NULL)
 		return ERR_PTR(error);
-	}
 
 	f->f_flags = flags;
-	return __dentry_open(dentry, mnt, f, NULL, cred);
+	f->f_path = *path;
+	path_get(&f->f_path);
+	error = do_dentry_open(f, NULL, cred);
+	if (!error) {
+		error = open_check_o_direct(f);
+		if (error) {
+			fput(f);
+			f = ERR_PTR(error);
+		}
+	} else { 
+		put_filp(f);
+		f = ERR_PTR(error);
+	}
+	return f;
 }
 EXPORT_SYMBOL(dentry_open);