On Fri, Mar 07, 2014 at 01:55:52PM -0500, J. Bruce Fields wrote: > On Thu, Mar 06, 2014 at 09:35:01AM -0500, Trond Myklebust wrote: > > > > On Mar 6, 2014, at 9:16, Yan, Zheng <zheng.z.yan@xxxxxxxxx> wrote: > > > > > From: David Howells <dhowells@xxxxxxxxxx> > > > > > > Make __d_materialise_dentry() set the materialised dentry name correctly by > > > flipping the arguments to switch_names(). > > > > > > switch_names() is lazy: if both names are internal to their dentries, it'll > > > overwrite that of the first dentry with that of the second, and won't update > > > that of the second. > > > > > > In the case of __d_materialise_dentry(), the second is an already extant > > > anonymous dentry that we want to insert into the tree in place of the dentry we > > > just looked up[*]. However, the dentry we just looked up carries the name we > > > actually want to use. > > > > > > [*] This is used by NFS to join a mount of a subtree into a mount of a tree > > > nearer the root when the two meet, where both mounts share a superblock and > > > thus a set of dentries. > > > > > > Signed-off-by: David Howells <dhowells@xxxxxxxxxx> > > > --- > > > fs/dcache.c | 2 +- > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > > > diff --git a/fs/dcache.c b/fs/dcache.c > > > index 265e0ce..ff779d4 100644 > > > --- a/fs/dcache.c > > > +++ b/fs/dcache.c > > > @@ -2698,7 +2698,7 @@ static void __d_materialise_dentry(struct dentry *dentry, struct dentry *anon) > > > > > > dparent = dentry->d_parent; > > > > > > - switch_names(dentry, anon); > > > + switch_names(anon, dentry); > > > swap(dentry->d_name.hash, anon->d_name.hash); > > > > > > dentry->d_parent = dentry; > > > > Well spotted... > > > > We ought to better document the fact that ’switch_names’ is asymmetrical. Perhaps change it to ‘update_target_name’, and then switch the argument names so that the ’target’ really is the thing that gets updated? > > Probably not worth it if Miklos's RENAME_EXCHANGE operation is making it > symmetrical soon anyway?: > > http://mid.gmane.org/<1380643239-16060-4-git-send-email-miklos@xxxxxxxxxx> To clarify: I mean, the suggested cleanup may not be worth it. The __d_materialise_dentry bugfix of course is. (What I wonder about is the duplication between this and __d_move. Is there any way to make d_materialise_unique a special case of d_move?) --b. -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
