On Mon, 2018-05-28 at 11:59 +0200, Greg Kroah-Hartman wrote: > 4.4-stable review patch. If anyone has any objections, please let me know. > > ------------------ > > From: Al Viro <viro@xxxxxxxxxxxxxxxxxx> > > commit 1e2e547a93a00ebc21582c06ca3c6cfea2a309ee upstream. > > For anything NFS-exported we do _not_ want to unlock new inode > before it has grown an alias; original set of fixes got the > ordering right, but missed the nasty complication in case of > lockdep being enabled - unlock_new_inode() does > lockdep_annotate_inode_mutex_key(inode) > which can only be done before anyone gets a chance to touch > ->i_mutex. Unfortunately, flipping the order and doing > unlock_new_inode() before d_instantiate() opens a window when > mkdir can race with open-by-fhandle on a guessed fhandle, leading > to multiple aliases for a directory inode and all the breakage > that follows from that. > > Correct solution: a new primitive (d_instantiate_new()) > combining these two in the right order - lockdep annotate, then > d_instantiate(), then the rest of unlock_new_inode(). All > combinations of d_instantiate() with unlock_new_inode() should > be converted to that. [...] I think you missed xfs, which has a wrapper around unlock_new_inode() called xfs_finish_inode_setup(). It looks like xfs_generic_create() and xfs_vn_symlink() still need this conversion. Ben. -- Ben Hutchings, Software Developer Codethink Ltd https://www.codethink.co.uk/ Dale House, 35 Dale Street Manchester, M1 2HF, United Kingdom
