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."
--b.
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