Jeff Layton wrote: > On Fri, 14 May 2010 13:17:51 -0400 > Trond Myklebust <trond.myklebust@xxxxxxxxxx> wrote: > > > On Fri, 2010-05-14 at 05:58 -0400, Jeff Layton wrote: > > > On Fri, 14 May 2010 17:35:27 +0800 > > > Mi Jinlong <mijinlong@xxxxxxxxxxxxxx> wrote: > > > > > > > After client get one file's READ delegation through NFSv4, > > > > server delete this file but don't reclaim the delegation. > > > > > > > > This patch add break_lease at may_delete, which can reclaim delegations. > > > > > > > > --- > > > > fs/namei.c | 2 +- > > > > 1 files changed, 1 insertions(+), 1 deletions(-) > > > > > > > > diff --git a/fs/namei.c b/fs/namei.c > > > > index 16df727..17bafc1 100644 > > > > --- a/fs/namei.c > > > > +++ b/fs/namei.c > > > > @@ -1338,7 +1338,7 @@ static int may_delete(struct inode *dir,struct dentry *victim,int isdir) > > > > return -ENOENT; > > > > if (victim->d_flags & DCACHE_NFSFS_RENAMED) > > > > return -EBUSY; > > > > - return 0; > > > > + return break_lease(victim->d_inode, FMODE_WRITE); > > > > } > > > > > > > > /* Check whether we can create an object with dentry child in directory > > > > > > This doesn't look right to me. > > > > > > The fcntl(2) manpage basically says that leases should be broken if the > > > file is opened for read or write, or is truncated. unlinks don't seem > > > to fall into either category... > > > > > > > Breaking the lease in this case is certainly a requirement for NFSv4 > > delegations. I've no idea what the CIFS oplock requirements are... > > > > Heh, probably "undefined". Windows generally doesn't allow you to > delete open files at all. I think you can delete open files on Windows nowadays, if they are opened with a particular flag. > I don't think samba will really care too much either way. I suppose > it could hurt performance in situations where you had a file that > was hardlinked and deleted a hardlink that was "unrelated" to the > dentry being held open...but that's pretty clearly a corner case at > best. Leases are handy for some userspace caching tricks too. (inotify is too late for some coherent things: the file is modified first, then you find out.) I wouldn't like deleting a hard-link to have that effect if it can be avoided. Or renaming (see below). > At the risk of being lazy and not checking for myself...what in the > NFSv4 spec mandates this? On the same note, if deleting any link of a hard-link file requires this, surely renaming a file requires it too, because that's roughly equivalent to making a new link and deleting the old one. -- Jamie -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
