Messages in this thread | | | Date | Mon, 16 Mar 2015 22:33:45 +0000 | From | Al Viro <> | Subject | Re: [PATCH 06/13] VFS/namei: new flag to support RCU symlinks: LOOKUP_LINK_RCU. |
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On Mon, Mar 16, 2015 at 03:43:20PM +1100, NeilBrown wrote: > When we support ->follow_link in RCU-walk we will not want to > take a reference to the 'struct path *link' passed to follow_link, > and correspondingly will not want to drop that reference. > > As link_path_walk will complete_walk() in the case of an error, > and as complete_walk() will clear LOOKUP_RCU, we cannot test > LOOKUP_RCU to determine if the path should be 'put'. > > So introduce a new flag: LOOKUP_LINK_RCU. This is set on > entry to follow_link() if appropriate and put_link() will > only call path_put() if it is clear.
Umm... How is it different from nd->depth > 0 && nd->flags & LOOKUP_RCU? IOW, could we bump nd->depth before that (conditional) mntget()?
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