PATCH [6/10] lease interfaces for version 4 NFSD

PATCH [6/10] lease interfaces for version 4 NFSD

[William A.(Andy) Adamson]

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VFS: nfsd will not have a file descriptor, nor an owner on the filp. nfsd also 
will not use signals. Seperate the lease processing code from fcntl_setlease() 
into a  __setlease() call.


Signed-off-by: Andy Adamson <andros@umich.edu>


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diff --recursive -puN old/fs/locks.c new/fs/locks.c
--- old/fs/locks.c	2004-09-20 13:36:41.571386000 -0400
+++ new/fs/locks.c	2004-09-20 13:56:25.385316000 -0400
@@ -1252,37 +1252,29 @@ int fcntl_getlease(struct file *filp)
 }
 
 /**
- *	fcntl_setlease	-	sets a lease on an open file
- *	@fd: open file descriptor
+ *	__setlease	-	sets a lease on an open file
  *	@filp: file pointer
  *	@arg: type of lease to obtain
+ *	@flp: input - file_lock to use, output - file_lock inserted 
  *
- *	Call this fcntl to establish a lease on the file.
- *	Note that you also need to call %F_SETSIG to
- *	receive a signal when the lease is broken.
+ *	The (input) flp->fl_lmops->fl_break function is required
+ *	by break_lease
+ *
+ *	Called with kernel lock held.
  */
-int fcntl_setlease(unsigned int fd, struct file *filp, long arg)
+int __setlease(struct file *filp, long arg, struct file_lock **flp)
 {
 	struct file_lock *fl, **before, **my_before = NULL;
-	struct dentry *dentry;
-	struct inode *inode;
+	struct dentry *dentry = filp->f_dentry;
+	struct inode *inode = dentry->d_inode;
 	int error, rdlease_count = 0, wrlease_count = 0;
 
-	dentry = filp->f_dentry;
-	inode = dentry->d_inode;
-
-	if ((current->fsuid != inode->i_uid) && !capable(CAP_LEASE))
-		return -EACCES;
-	if (!S_ISREG(inode->i_mode))
-		return -EINVAL;
-	error = security_file_lock(filp, arg);
-	if (error)
-		return error;
-
-	lock_kernel();
-
 	time_out_leases(inode);
 
+	error = -EINVAL;
+	if (!flp || !(*flp) || !(*flp)->fl_lmops || !(*flp)->fl_lmops->fl_break)
+		goto out;
+
 	/*
 	 * FIXME: What about F_RDLCK and files open for writing?
 	 */
@@ -1290,7 +1282,7 @@ int fcntl_setlease(unsigned int fd, stru
 	if ((arg == F_WRLCK)
 	    && ((atomic_read(&dentry->d_count) > 1)
 		|| (atomic_read(&inode->i_count) > 1)))
-		goto out_unlock;
+		goto out;
 
 	/*
 	 * At this point, we know that if there is an exclusive
@@ -1318,39 +1310,83 @@ int fcntl_setlease(unsigned int fd, stru
 
 	if ((arg == F_RDLCK && (wrlease_count > 0)) ||
 	    (arg == F_WRLCK && ((rdlease_count + wrlease_count) > 0)))
-		goto out_unlock;
+		goto out;
 
 	if (my_before != NULL) {
 		error = lease_modify(my_before, arg);
-		goto out_unlock;
+		goto out;
 	}
 
 	error = 0;
 	if (arg == F_UNLCK)
-		goto out_unlock;
+		goto out;
 
 	error = -EINVAL;
 	if (!leases_enable)
-		goto out_unlock;
+		goto out;
 
 	error = lease_alloc(filp, arg, &fl);
 	if (error)
-		goto out_unlock;
+		goto out;
 
-	error = fasync_helper(fd, filp, 1, &fl->fl_fasync);
-	if (error < 0) {
-		locks_free_lock(fl);
-		goto out_unlock;
-	}
+	locks_copy_lock(fl, lease);
 
 	locks_insert_lock(before, fl);
 
+out:
+	return error;
+}
+
+/**
+ *	fcntl_setlease  -       sets a lease on an open file
+ *	@fd: open file descriptor
+ *	@filp: file pointer
+ *	@arg: type of lease to obtain
+ *
+ *	Call this fcntl to establish a lease on the file.
+ *	Uses default fl_break function.
+ *	Note that you also need to call %F_SETSIG to
+ *	receive a signal when the lease is broken.
+ */
+int fcntl_setlease(unsigned int fd, struct file *filp, long arg)
+{
+	struct file_lock fl, *flp = &fl;
+	struct dentry *dentry = filp->f_dentry;
+	struct inode *inode = dentry->d_inode;
+	int error;
+
+	if ((current->fsuid != inode->i_uid) && !capable(CAP_LEASE))
+		return -EACCES;
+	if (!S_ISREG(inode->i_mode))
+		return -EINVAL;
+	error = security_file_lock(filp, arg);
+	if (error)
+		return error;
+
+	locks_init_lock(&fl);
+        if ((error = lease_init(filp, arg, &fl)))
+                return error;
+
+	lock_kernel();
+	if((error = __setlease(filp, arg, &flp)))
+		goto out;
+
+	error = fasync_helper(fd, filp, 1, &flp->fl_fasync);
+	if (error < 0) {
+		/* remove lease just inserted by __setlease */
+		flp->fl_type = F_UNLCK | F_INPROGRESS;
+		flp->fl_break_time = jiffies - 10;
+		time_out_leases(inode);
+		goto out;
+	}
+
 	error = f_setown(filp, current->pid, 0);
-out_unlock:
+out:
 	unlock_kernel();
 	return error;
 }
 
+
 /**
  * flock_lock_file_wait - Apply a FLOCK-style lock to a file
  * @filp: The file to apply the lock to

Re: PATCH [6/10] lease interfaces for version 4 NFSD

[Matthew Wilcox]

On Mon, Sep 20, 2004 at 04:23:00PM -0400, William A.(Andy) Adamson wrote:
> +	locks_init_lock(&fl);
> +        if ((error = lease_init(filp, arg, &fl)))
> +                return error;
> +	lock_kernel();
> +	if((error = __setlease(filp, arg, &flp)))
> +		goto out;
> +

Please follow kernel coding style.  That means:
 - Tabs, not spaces for indentation.
 - No assignment within if ()
 - Space between if and (
ie write this bit as:

	locks_init_lock(&fl);
	error = lease_init(filp, arg, &fl);
	if (error)
		return error;
	lock_kernel();
	error = __setlease(filp, arg, &flp);
	if (error)
		goto out;

>  	return error;
>  }
>  
> +
>  /**
>   * flock_lock_file_wait - Apply a FLOCK-style lock to a file
>   * @filp: The file to apply the lock to

Don't put this additional line in.  I don't like it.

-- 
"Next the statesmen will invent cheap lies, putting the blame upon 
the nation that is attacked, and every man will be glad of those
conscience-soothing falsities, and will diligently study them, and refuse
to examine any refutations of them; and thus he will by and by convince 
himself that the war is just, and will thank God for the better sleep 
he enjoys after this process of grotesque self-deception." -- Mark Twain

Re: PATCH [6/10] lease interfaces for version 4 NFSD

[William A.(Andy) Adamson]

> On Mon, Sep 20, 2004 at 04:23:00PM -0400, William A.(Andy) Adamson wrote:
> > +	locks_init_lock(&fl);
> > +        if ((error = lease_init(filp, arg, &fl)))
> > +                return error;
> > +	lock_kernel();
> > +	if((error = __setlease(filp, arg, &flp)))
> > +		goto out;
> > +
> 
> Please follow kernel coding style.  That means:

ok. 

BTW: i just noted that there are two emails with PATCH [9/10] in the title. 
they are different patches...

-->Andy


>  - Tabs, not spaces for indentation.
>  - No assignment within if ()
>  - Space between if and (
> ie write this bit as:
> 
> 	locks_init_lock(&fl);
> 	error = lease_init(filp, arg, &fl);
> 	if (error)
> 		return error;
> 	lock_kernel();
> 	error = __setlease(filp, arg, &flp);
> 	if (error)
> 		goto out;
> 
> >  	return error;
> >  }
> >  
> > +
> >  /**
> >   * flock_lock_file_wait - Apply a FLOCK-style lock to a file
> >   * @filp: The file to apply the lock to
> 
> Don't put this additional line in.  I don't like it.
> 
> -- 
> "Next the statesmen will invent cheap lies, putting the blame upon 
> the nation that is attacked, and every man will be glad of those
> conscience-soothing falsities, and will diligently study them, and refuse
> to examine any refutations of them; and thus he will by and by convince 
> himself that the war is just, and will thank God for the better sleep 
> he enjoys after this process of grotesque self-deception." -- Mark Twain
>