ext4: Fix NULL dereference in ext4_ext_migrate()'s error handling

This was found through a code checker (http://repo.or.cz/w/smatch.git/).
It looks like you might be able to trigger the error by trying to migrate
a readonly file system.

Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

diff --git a/fs/ext4/migrate.c b/fs/ext4/migrate.c
index 734abca25e359bc4b21f3e8b67674cc9c320698a..fe64d9f79852f1dc22764cfa00f261c84858107b 100644 (file)
--- a/fs/ext4/migrate.c
+++ b/fs/ext4/migrate.c
@@ -481,7 +481,7 @@ int ext4_ext_migrate(struct inode *inode)
                                        + 1);
        if (IS_ERR(handle)) {
                retval = PTR_ERR(handle);
-               goto err_out;
+               return retval;
        }
        tmp_inode = ext4_new_inode(handle,
                                inode->i_sb->s_root->d_inode,
@@ -489,8 +489,7 @@ int ext4_ext_migrate(struct inode *inode)
        if (IS_ERR(tmp_inode)) {
                retval = -ENOMEM;
                ext4_journal_stop(handle);
-               tmp_inode = NULL;
-               goto err_out;
+               return retval;
        }
        i_size_write(tmp_inode, i_size_read(inode));
        /*
@@ -618,8 +617,7 @@ err_out:
 
        ext4_journal_stop(handle);
 
-       if (tmp_inode)
-               iput(tmp_inode);
+       iput(tmp_inode);
 
        return retval;
 }