[PATCH 12/n] kill spurious reference to vmtruncate

[Christoph Hellwig <hch@infradead.org>]

Lots of filesystems calls vmtruncate despite not implementing the old
->truncate method.  Switch them to use simple_setsize and add some
comments about the truncate code where it seems fitting.


Signed-off-by: Christoph Hellwig <hch@lst.de>

Index: vfs-2.6.git/fs/ufs/truncate.c
===================================================================
--- vfs-2.6.git.orig/fs/ufs/truncate.c	2009-09-22 13:08:36.842264538 -0300
+++ vfs-2.6.git/fs/ufs/truncate.c	2009-09-22 13:12:13.926305949 -0300
@@ -500,12 +500,10 @@ out:
 	return err;
 }
 
-
 /*
- * We don't define our `inode->i_op->truncate', and call it here,
- * because of:
- * - there is no way to know old size
- * - there is no way inform user about error, if it happens in `truncate'
+ * TODO:
+ *	- truncate case should use proper ordering instead of using
+ *	  simple_setsize
  */
 static int ufs_setattr(struct dentry *dentry, struct iattr *attr)
 {
@@ -520,7 +518,7 @@ static int ufs_setattr(struct dentry *de
 	if (ia_valid & ATTR_SIZE &&
 	    attr->ia_size != i_size_read(inode)) {
 		loff_t old_i_size = inode->i_size;
-		error = vmtruncate(inode, attr->ia_size);
+		error = simple_setsize(inode, attr->ia_size);
 		if (error)
 			return error;
 		error = ufs_truncate(inode, old_i_size);
Index: vfs-2.6.git/fs/adfs/inode.c
===================================================================
--- vfs-2.6.git.orig/fs/adfs/inode.c	2009-09-22 13:18:00.242265034 -0300
+++ vfs-2.6.git/fs/adfs/inode.c	2009-09-22 13:18:33.437781151 -0300
@@ -328,8 +328,9 @@ adfs_notify_change(struct dentry *dentry
 	if (error)
 		goto out;
 
+	/* XXX: this is missing some actual on-disk truncation.. */
 	if (ia_valid & ATTR_SIZE)
-		error = vmtruncate(inode, attr->ia_size);
+		error = simple_setsize(inode, attr->ia_size);
 
 	if (error)
 		goto out;
Index: vfs-2.6.git/fs/ecryptfs/inode.c
===================================================================
--- vfs-2.6.git.orig/fs/ecryptfs/inode.c	2009-09-22 13:20:16.726261535 -0300
+++ vfs-2.6.git/fs/ecryptfs/inode.c	2009-09-22 13:21:30.893762356 -0300
@@ -831,9 +831,15 @@ int ecryptfs_truncate(struct dentry *den
 				    - (new_length & ~PAGE_CACHE_MASK));
 
 		if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
-			rc = vmtruncate(inode, new_length);
+			rc = simple_setsize(inode, new_length);
 			if (rc)
 				goto out_free;
+
+			/*
+			 * XXX: this is horribly buggy as we can't and never
+			 * could rely on the lower inode having a ->truncate
+			 * method to actually release blocks.
+			 */
 			rc = vmtruncate(lower_dentry->d_inode, new_length);
 			goto out_free;
 		}
@@ -855,7 +861,7 @@ int ecryptfs_truncate(struct dentry *den
 				goto out_free;
 			}
 		}
-		vmtruncate(inode, new_length);
+		simple_setsize(inode, new_length);
 		rc = ecryptfs_write_inode_size_to_metadata(inode);
 		if (rc) {
 			printk(KERN_ERR	"Problem with "
@@ -870,6 +876,11 @@ int ecryptfs_truncate(struct dentry *den
 		lower_size_after_truncate =
 		    upper_size_to_lower_size(crypt_stat, new_length);
 		if (lower_size_after_truncate < lower_size_before_truncate)
+			/*
+			 * XXX: this is horribly buggy as we can't and never
+			 * could rely on the lower inode having a ->truncate
+			 * method to actually release blocks.
+			 */
 			vmtruncate(lower_dentry->d_inode,
 				   lower_size_after_truncate);
 	}
Index: vfs-2.6.git/fs/gfs2/aops.c
===================================================================
--- vfs-2.6.git.orig/fs/gfs2/aops.c	2009-09-22 13:15:40.718262195 -0300
+++ vfs-2.6.git/fs/gfs2/aops.c	2009-09-22 13:16:45.265763898 -0300
@@ -710,8 +710,14 @@ out:
 		return 0;
 
 	page_cache_release(page);
+
+	/*
+	 * XXX(hch): the call below should probably be replaced with
+	 * a call to the gfs2-specific truncate blocks helper to actually
+	 * release disk blocks..
+	 */
 	if (pos + len > ip->i_inode.i_size)
-		vmtruncate(&ip->i_inode, ip->i_inode.i_size);
+		simple_setsize(&ip->i_inode, ip->i_inode.i_size);
 out_endtrans:
 	gfs2_trans_end(sdp);
 out_trans_fail:
Index: vfs-2.6.git/fs/gfs2/ops_inode.c
===================================================================
--- vfs-2.6.git.orig/fs/gfs2/ops_inode.c	2009-09-22 13:16:48.901764352 -0300
+++ vfs-2.6.git/fs/gfs2/ops_inode.c	2009-09-22 13:17:30.256367942 -0300
@@ -1129,6 +1129,9 @@ int gfs2_permission(struct inode *inode,
 	return error;
 }
 
+/*
+ * XXX: should be changed to have proper ordering by opencoding simple_setsize
+ */
 static int setattr_size(struct inode *inode, struct iattr *attr)
 {
 	struct gfs2_inode *ip = GFS2_I(inode);
@@ -1139,7 +1142,7 @@ static int setattr_size(struct inode *in
 		error = gfs2_trans_begin(sdp, 0, sdp->sd_jdesc->jd_blocks);
 		if (error)
 			return error;
-		error = vmtruncate(inode, attr->ia_size);
+		error = simple_setsize(inode, attr->ia_size);
 		gfs2_trans_end(sdp);
 		if (error) 
 			return error;
Index: vfs-2.6.git/fs/jffs2/fs.c
===================================================================
--- vfs-2.6.git.orig/fs/jffs2/fs.c	2009-09-22 13:18:47.962264848 -0300
+++ vfs-2.6.git/fs/jffs2/fs.c	2009-09-22 13:21:42.981761532 -0300
@@ -169,13 +169,13 @@ int jffs2_do_setattr (struct inode *inod
 	mutex_unlock(&f->sem);
 	jffs2_complete_reservation(c);
 
-	/* We have to do the vmtruncate() without f->sem held, since
+	/* We have to do the simple_setsize() without f->sem held, since
 	   some pages may be locked and waiting for it in readpage().
 	   We are protected from a simultaneous write() extending i_size
 	   back past iattr->ia_size, because do_truncate() holds the
 	   generic inode semaphore. */
 	if (ivalid & ATTR_SIZE && inode->i_size > iattr->ia_size) {
-		vmtruncate(inode, iattr->ia_size);	
+		simple_setsize(inode, iattr->ia_size);
 		inode->i_blocks = (inode->i_size + 511) >> 9;
 	}	
 
Index: vfs-2.6.git/fs/ocfs2/file.c
===================================================================
--- vfs-2.6.git.orig/fs/ocfs2/file.c	2009-09-22 13:14:22.849791263 -0300
+++ vfs-2.6.git/fs/ocfs2/file.c	2009-09-22 13:15:26.746262469 -0300
@@ -1021,7 +1021,7 @@ int ocfs2_setattr(struct dentry *dentry,
 	}
 
 	/*
-	 * This will intentionally not wind up calling vmtruncate(),
+	 * This will intentionally not wind up calling simple_setsize(),
 	 * since all the work for a size change has been done above.
 	 * Otherwise, we could get into problems with truncate as
 	 * ip_alloc_sem is used there to protect against i_size
@@ -1864,9 +1864,13 @@ relock:
 			 * direct write may have instantiated a few
 			 * blocks outside i_size. Trim these off again.
 			 * Don't need i_size_read because we hold i_mutex.
+			 *
+			 * XXX(hch): this looks buggy because ocfs2 did not
+			 * actually implement ->truncate.  Take a look at
+			 * the new truncate sequence and update this accordingly
 			 */
 			if (*ppos + count > inode->i_size)
-				vmtruncate(inode, inode->i_size);
+				simple_setsize(inode, inode->i_size);
 			ret = written;
 			goto out_dio;
 		}
Index: vfs-2.6.git/fs/smbfs/inode.c
===================================================================
--- vfs-2.6.git.orig/fs/smbfs/inode.c	2009-09-22 13:12:18.913764201 -0300
+++ vfs-2.6.git/fs/smbfs/inode.c	2009-09-22 13:12:48.649797002 -0300
@@ -712,7 +712,7 @@ smb_notify_change(struct dentry *dentry,
 		error = server->ops->truncate(inode, attr->ia_size);
 		if (error)
 			goto out;
-		error = vmtruncate(inode, attr->ia_size);
+		error = simple_setsize(inode, attr->ia_size);
 		if (error)
 			goto out;
 		refresh = 1;
Index: vfs-2.6.git/fs/ubifs/file.c
===================================================================
--- vfs-2.6.git.orig/fs/ubifs/file.c	2009-09-22 13:12:56.969768178 -0300
+++ vfs-2.6.git/fs/ubifs/file.c	2009-09-22 13:13:59.161870394 -0300
@@ -966,12 +966,15 @@ static int do_writepage(struct page *pag
  * the page locked, and it locks @ui_mutex. However, write-back does take inode
  * @i_mutex, which means other VFS operations may be run on this inode at the
  * same time. And the problematic one is truncation to smaller size, from where
- * we have to call 'vmtruncate()', which first changes @inode->i_size, then
+ * we have to call 'simple_setsize()', which first changes @inode->i_size, then
  * drops the truncated pages. And while dropping the pages, it takes the page
- * lock. This means that 'do_truncation()' cannot call 'vmtruncate()' with
+ * lock. This means that 'do_truncation()' cannot call 'simple_setsize()' with
  * @ui_mutex locked, because it would deadlock with 'ubifs_writepage()'. This
  * means that @inode->i_size is changed while @ui_mutex is unlocked.
  *
+ * XXX: with the new truncate the above is not true anymore, the simple_setsize
+ * calls can be replaced with the individual components.
+ *
  * But in 'ubifs_writepage()' we have to guarantee that we do not write beyond
  * inode size. How do we do this if @inode->i_size may became smaller while we
  * are in the middle of 'ubifs_writepage()'? The UBIFS solution is the
@@ -1124,7 +1127,7 @@ static int do_truncation(struct ubifs_in
 		budgeted = 0;
 	}
 
-	err = vmtruncate(inode, new_size);
+	err = simple_setsize(inode, new_size);
 	if (err)
 		goto out_budg;
 
@@ -1213,7 +1216,7 @@ static int do_setattr(struct ubifs_info 
 
 	if (attr->ia_valid & ATTR_SIZE) {
 		dbg_gen("size %lld -> %lld", inode->i_size, new_size);
-		err = vmtruncate(inode, new_size);
+		err = simple_setsize(inode, new_size);
 		if (err)
 			goto out;
 	}
@@ -1222,7 +1225,7 @@ static int do_setattr(struct ubifs_info 
 	if (attr->ia_valid & ATTR_SIZE) {
 		/* Truncation changes inode [mc]time */
 		inode->i_mtime = inode->i_ctime = ubifs_current_time(inode);
-		/* 'vmtruncate()' changed @i_size, update @ui_size */
+		/* 'simple_setsize()' changed @i_size, update @ui_size */
 		ui->ui_size = inode->i_size;
 	}
 
Index: vfs-2.6.git/fs/ubifs/ubifs.h
===================================================================
--- vfs-2.6.git.orig/fs/ubifs/ubifs.h	2009-09-22 13:14:03.945800885 -0300
+++ vfs-2.6.git/fs/ubifs/ubifs.h	2009-09-22 13:14:13.014300584 -0300
@@ -378,7 +378,7 @@ struct ubifs_gced_idx_leb {
  * The @ui_size is a "shadow" variable for @inode->i_size and UBIFS uses
  * @ui_size instead of @inode->i_size. The reason for this is that UBIFS cannot
  * make sure @inode->i_size is always changed under @ui_mutex, because it
- * cannot call 'vmtruncate()' with @ui_mutex locked, because it would deadlock
+ * cannot call 'simple_setsize()' with @ui_mutex locked, because it would deadlock
  * with 'ubifs_writepage()' (see file.c). All the other inode fields are
  * changed under @ui_mutex, so they do not need "shadow" fields. Note, one
  * could consider to rework locking and base it on "shadow" fields.