On Tue, 9 Jul 2013 15:38:36 -0400 "J. Bruce Fields" <bfields@xxxxxxxxxx> wrote: > On Tue, Jul 09, 2013 at 09:23:10AM -0400, Jeff Layton wrote: > > On Wed, 3 Jul 2013 16:12:33 -0400 > > "J. Bruce Fields" <bfields@xxxxxxxxxx> wrote: > > > > > From: "J. Bruce Fields" <bfields@xxxxxxxxxx> > > > > > > We'll need the same logic for rename and link. > > > > > > Signed-off-by: J. Bruce Fields <bfields@xxxxxxxxxx> > > > --- > > > fs/namei.c | 13 +++---------- > > > include/linux/fs.h | 33 +++++++++++++++++++++++++++++++-- > > > 2 files changed, 34 insertions(+), 12 deletions(-) > > > > > > diff --git a/fs/namei.c b/fs/namei.c > > > index cba3db1..a9d4031 100644 > > > --- a/fs/namei.c > > > +++ b/fs/namei.c > > > @@ -3401,14 +3401,9 @@ int vfs_unlink(struct inode *dir, struct dentry *dentry, struct inode **delegate > > > else { > > > error = security_inode_unlink(dir, dentry); > > > if (!error) { > > > - error = break_deleg(target, O_WRONLY|O_NONBLOCK); > > > - if (error) { > > > - if (error == -EWOULDBLOCK && delegated_inode) { > > > - *delegated_inode = target; > > > - ihold(target); > > > - } > > > + error = try_break_deleg(target, delegated_inode); > > > + if (error) > > > goto out; > > > - } > > > error = dir->i_op->unlink(dir, dentry); > > > if (!error) > > > dont_mount(dentry); > > > @@ -3478,9 +3473,7 @@ exit2: > > > iput(inode); /* truncate the inode here */ > > > inode = NULL; > > > if (delegated_inode) { > > > - error = break_deleg(delegated_inode, O_WRONLY); > > > - iput(delegated_inode); > > > - delegated_inode = NULL; > > > + error = break_deleg_wait(&delegated_inode); > > > if (!error) > > > goto retry_deleg; > > > } > > > diff --git a/include/linux/fs.h b/include/linux/fs.h > > > index f951588..c37e463 100644 > > > --- a/include/linux/fs.h > > > +++ b/include/linux/fs.h > > > @@ -1894,6 +1894,9 @@ extern bool our_mnt(struct vfsmount *mnt); > > > > > > extern int current_umask(void); > > > > > > +extern void ihold(struct inode * inode); > > > +extern void iput(struct inode *); > > > + > > > /* /sys/fs */ > > > extern struct kobject *fs_kobj; > > > > > > @@ -1962,6 +1965,28 @@ static inline int break_deleg(struct inode *inode, unsigned int mode) > > > return 0; > > > } > > > > > > +static inline int try_break_deleg(struct inode *inode, struct inode **delegated_inode) > > > +{ > > > + int ret; > > > + > > > + ret = break_deleg(inode, O_WRONLY|O_NONBLOCK); > > > + if (ret == -EWOULDBLOCK && delegated_inode) { > > > + *delegated_inode = inode; > > > + ihold(inode); > > > + } > > > + return ret; > > > +} > > > + > > > > Actually, now that I look... > > > > Suppose a vfs_unlink caller passes in a NULL delegated_inode pointer. > > He'll get back a -EWOULDBLOCK here if there's a delegation on it. > > Presumably he'll just treat that as a hard error and the delegation > > would never get broken. Is that expected? > > Yes. > > The callers that pass in NULL are callers who should really never > encounter a write delegation. E.g. it might happen if you exported a > filesystem that you're also stacking ecryptfs on top of (assuming that's > possible). Maybe I'm missing something, but that looks pointless. > Erroring out seems a safe way to handle it. > > It wouldn't be a problem to convert more of those callers to do the same > retry loop, it just seems better to avoid the extra spaghetti to support > what looks like a nutty use case. > > --b. Ok, thanks for clarifying that. I agree that those others are nutty use-cases, at least for now. If someone were to ever allow setting of FL_DELEGs from userland though they'll probably need to contend with them. -- Jeff Layton <jlayton@xxxxxxxxxx> -- 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