On Tue, 9 Jul 2013 16:51:01 -0400
"J. Bruce Fields" <bfields@xxxxxxxxxx> wrote:
> On Tue, Jul 09, 2013 at 09:30:47AM -0400, Jeff Layton wrote:
> > On Wed, 3 Jul 2013 16:12:36 -0400
> > "J. Bruce Fields" <bfields@xxxxxxxxxx> wrote:
> >
> > > From: "J. Bruce Fields" <bfields@xxxxxxxxxx>
> > >
> > > NFSv4 uses leases to guarantee that clients can cache metadata as well
> > > as data.
> > >
> > > Cc: Mikulas Patocka <mikulas@xxxxxxxxxxxxxxxxxxxxxxxx>
> > > Cc: David Howells <dhowells@xxxxxxxxxx>
> > > Cc: Tyler Hicks <tyhicks@xxxxxxxxxxxxx>
> > > Cc: Dustin Kirkland <dustin.kirkland@xxxxxxxxxxx>
> > > Signed-off-by: J. Bruce Fields <bfields@xxxxxxxxxx>
> > > ---
> > > drivers/base/devtmpfs.c | 4 ++--
> > > fs/attr.c | 5 ++++-
> > > fs/cachefiles/interface.c | 4 ++--
> > > fs/ecryptfs/inode.c | 2 +-
> > > fs/hpfs/namei.c | 2 +-
> > > fs/inode.c | 6 +++++-
> > > fs/nfsd/vfs.c | 8 ++++++--
> > > fs/open.c | 21 +++++++++++++++++----
> > > fs/utimes.c | 9 ++++++++-
> > > include/linux/fs.h | 2 +-
> > > 10 files changed, 47 insertions(+), 16 deletions(-)
> > >
> > > diff --git a/drivers/base/devtmpfs.c b/drivers/base/devtmpfs.c
> > > index 1b8490e..0f38201 100644
> > > --- a/drivers/base/devtmpfs.c
> > > +++ b/drivers/base/devtmpfs.c
> > > @@ -216,7 +216,7 @@ static int handle_create(const char *nodename, umode_t mode, kuid_t uid,
> > > newattrs.ia_gid = gid;
> > > newattrs.ia_valid = ATTR_MODE|ATTR_UID|ATTR_GID;
> > > mutex_lock(&dentry->d_inode->i_mutex);
> > > - notify_change(dentry, &newattrs);
> > > + notify_change(dentry, &newattrs, NULL);
> > > mutex_unlock(&dentry->d_inode->i_mutex);
> > >
> > > /* mark as kernel-created inode */
> > > @@ -322,7 +322,7 @@ static int handle_remove(const char *nodename, struct device *dev)
> > > newattrs.ia_valid =
> > > ATTR_UID|ATTR_GID|ATTR_MODE;
> > > mutex_lock(&dentry->d_inode->i_mutex);
> > > - notify_change(dentry, &newattrs);
> > > + notify_change(dentry, &newattrs, NULL);
> > > mutex_unlock(&dentry->d_inode->i_mutex);
> > > err = vfs_unlink(parent.dentry->d_inode, dentry, NULL);
> > > if (!err || err == -ENOENT)
> > > diff --git a/fs/attr.c b/fs/attr.c
> > > index 1449adb..261f5c9 100644
> > > --- a/fs/attr.c
> > > +++ b/fs/attr.c
> > > @@ -167,7 +167,7 @@ void setattr_copy(struct inode *inode, const struct iattr *attr)
> > > }
> > > EXPORT_SYMBOL(setattr_copy);
> > >
> > > -int notify_change(struct dentry * dentry, struct iattr * attr)
> > > +int notify_change(struct dentry * dentry, struct iattr * attr, struct inode **delegated_inode)
> > > {
> > > struct inode *inode = dentry->d_inode;
> > > umode_t mode = inode->i_mode;
> > > @@ -243,6 +243,9 @@ int notify_change(struct dentry * dentry, struct iattr * attr)
> > > error = security_inode_setattr(dentry, attr);
> > > if (error)
> > > return error;
> > > + error = try_break_deleg(inode, delegated_inode);
> > > + if (error)
> > > + return error;
> > >
> > > if (inode->i_op->setattr)
> > > error = inode->i_op->setattr(dentry, attr);
> > > diff --git a/fs/cachefiles/interface.c b/fs/cachefiles/interface.c
> > > index 746ce53..40f5917 100644
> > > --- a/fs/cachefiles/interface.c
> > > +++ b/fs/cachefiles/interface.c
> > > @@ -417,14 +417,14 @@ static int cachefiles_attr_changed(struct fscache_object *_object)
> > > _debug("discard tail %llx", oi_size);
> > > newattrs.ia_valid = ATTR_SIZE;
> > > newattrs.ia_size = oi_size & PAGE_MASK;
> > > - ret = notify_change(object->backer, &newattrs);
> > > + ret = notify_change(object->backer, &newattrs, NULL);
> > > if (ret < 0)
> > > goto truncate_failed;
> > > }
> > >
> > > newattrs.ia_valid = ATTR_SIZE;
> > > newattrs.ia_size = ni_size;
> > > - ret = notify_change(object->backer, &newattrs);
> > > + ret = notify_change(object->backer, &newattrs, NULL);
> > >
> > > truncate_failed:
> > > mutex_unlock(&object->backer->d_inode->i_mutex);
> > > diff --git a/fs/ecryptfs/inode.c b/fs/ecryptfs/inode.c
> > > index 19e4435..bd54575 100644
> > > --- a/fs/ecryptfs/inode.c
> > > +++ b/fs/ecryptfs/inode.c
> > > @@ -992,7 +992,7 @@ static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
> > > lower_ia.ia_valid &= ~ATTR_MODE;
> > >
> > > mutex_lock(&lower_dentry->d_inode->i_mutex);
> > > - rc = notify_change(lower_dentry, &lower_ia);
> > > + rc = notify_change(lower_dentry, &lower_ia, NULL);
> > > mutex_unlock(&lower_dentry->d_inode->i_mutex);
> > > out:
> > > fsstack_copy_attr_all(inode, lower_inode);
> > > diff --git a/fs/hpfs/namei.c b/fs/hpfs/namei.c
> > > index 345713d..1b39afd 100644
> > > --- a/fs/hpfs/namei.c
> > > +++ b/fs/hpfs/namei.c
> > > @@ -407,7 +407,7 @@ again:
> > > /*printk("HPFS: truncating file before delete.\n");*/
> > > newattrs.ia_size = 0;
> > > newattrs.ia_valid = ATTR_SIZE | ATTR_CTIME;
> > > - err = notify_change(dentry, &newattrs);
> > > + err = notify_change(dentry, &newattrs, NULL);
> > > put_write_access(inode);
> > > if (!err)
> > > goto again;
> > > diff --git a/fs/inode.c b/fs/inode.c
> > > index 304db4c..664d631 100644
> > > --- a/fs/inode.c
> > > +++ b/fs/inode.c
> > > @@ -1633,7 +1633,11 @@ static int __remove_suid(struct dentry *dentry, int kill)
> > > struct iattr newattrs;
> > >
> > > newattrs.ia_valid = ATTR_FORCE | kill;
> > > - return notify_change(dentry, &newattrs);
> > > + /*
> > > + * Note we call this on write, so notify_change will not
> > > + * encounter any conflicting delegations:
> > > + */
> > > + return notify_change(dentry, &newattrs, NULL);
> > > }
> > >
> > > int file_remove_suid(struct file *file)
> > > diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
> > > index b9740cb..e781901 100644
> > > --- a/fs/nfsd/vfs.c
> > > +++ b/fs/nfsd/vfs.c
> > > @@ -426,7 +426,7 @@ nfsd_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp, struct iattr *iap,
> > > goto out_nfserr;
> > > fh_lock(fhp);
> > >
> > > - host_err = notify_change(dentry, iap);
> > > + host_err = notify_change(dentry, iap, NULL);
> > > err = nfserrno(host_err);
> > > fh_unlock(fhp);
> > > }
> > > @@ -959,7 +959,11 @@ static void kill_suid(struct dentry *dentry)
> > > ia.ia_valid = ATTR_KILL_SUID | ATTR_KILL_SGID | ATTR_KILL_PRIV;
> > >
> > > mutex_lock(&dentry->d_inode->i_mutex);
> > > - notify_change(dentry, &ia);
> > > + /*
> > > + * Note we call this on write, so notify_change will not
> > > + * encounter any conflicting delegations:
> > > + */
> > > + notify_change(dentry, &ia, NULL);
> > > mutex_unlock(&dentry->d_inode->i_mutex);
> > > }
> > >
> > > diff --git a/fs/open.c b/fs/open.c
> > > index 8c74100..1a39d29 100644
> > > --- a/fs/open.c
> > > +++ b/fs/open.c
> > > @@ -57,7 +57,7 @@ int do_truncate(struct dentry *dentry, loff_t length, unsigned int time_attrs,
> > > newattrs.ia_valid |= ret | ATTR_FORCE;
> > >
> > > mutex_lock(&dentry->d_inode->i_mutex);
> > > - ret = notify_change(dentry, &newattrs);
> > > + ret = notify_change(dentry, &newattrs, NULL);
> > > mutex_unlock(&dentry->d_inode->i_mutex);
> > > return ret;
> > > }
> >
> > Isn't it possible we'll need to break a delegation on truncate()?
>
> In the truncate case, the caller called break_lease, and in the
> ftruncate case it's called with a write open, and the open already broke
> any leases or delegations.
>
> Might need a comment--could I get away with just this?:
>
> mutex_lock(&dentry->d_inode->i_mutex);
> + /* NULL is safe: any delegations have already been broken: */
> ret = notify_change(dentry, &newattrs, NULL);
> mutex_unlock(&dentry->d_inode->i_mutex);
> return ret;
>
> I also added something to the notify_change kerneldoc: "passing NULL is
> fine for callers holding the file open for write, as there can be no
> conflicting delegation in that case."
>
Ahh ok, makes sense. Both comments sound like good additions.
Thanks,
--
Jeff Layton <jlayton@xxxxxxxxxx>
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