Messages in this thread | | | Date | Fri, 8 Jan 2010 18:22:01 -0800 (PST) | From | Linus Torvalds <> | Subject | Re: [RFC PATCH 0/2] Fix up the NFS mmap code |
| |
On Sat, 9 Jan 2010, Al Viro wrote: > > Well, sure - it steps on i_mutex-before-mmmap_sem first from ls somewhere and > records the ordering for posterity. Then NFS steps into mmap() (on a > different inode) and gets conflicting ordering.
Look closer: the inodes for directories and for non-directories have i_mutex in different lockdep classes.
So that "on a different inode" thing should have made it a non-issue, since there is no actual chain back. There is "mmap_sem -> i_mutex_regular_file" (for mmap) and there is "i_mutex_directory -> mmap_sem" (for filldir), but that isn't an ABBA.
The problem _seems_ to be (if I read Andi's chain correctly) that a directory hasn't gone through the i_mutex_dir_key change, so filldir ends up being counted against the default i_mutex_key.
Linus
| |