ocfs2: handle a symlink read error correctly

In the Linux kernel, the following vulnerability has been resolved: ocfs2: handle a symlink read error correctly Patch series "Convert ocfs2 to use folios". Mark did a conversion of ocfs2 to use folios and sent it to me as a giant patch for review ;-) So I've redone it as individual patches, and credited Mark for the patches where his code is substantially the same. It's not a bad way to do it; his patch had some bugs and my patches had some bugs. Hopefully all our bugs were different from each other. And hopefully Mark likes all the changes I made to his code! This patch (of 23): If we can't read the buffer, be sure to unlock the page before returning.