remove inode_setattr

Replace inode_setattr with opencoded variants of it in all callers.  This
moves the remaining call to vmtruncate into the filesystem methods where it
can be replaced with the proper truncate sequence.

In a few cases it was obvious that we would never end up calling vmtruncate
so it was left out in the opencoded variant:

 spufs: explicitly checks for ATTR_SIZE earlier
 btrfs,hugetlbfs,logfs,dlmfs: explicitly clears ATTR_SIZE earlier
 ufs: contains an opencoded simple_seattr + truncate that sets the filesize just above

In addition to that ncpfs called inode_setattr with handcrafted iattrs,
which allowed to trim down the opencoded variant.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/ext4/inode.c

@@ -5539,11 +5539,19 @@ int ext4_setattr(struct dentry *dentry, struct iattr *attr)
 			ext4_truncate(inode);
 	}
 
-	rc = inode_setattr(inode, attr);
+	if ((attr->ia_valid & ATTR_SIZE) &&
+	    attr->ia_size != i_size_read(inode))
+		rc = vmtruncate(inode, attr->ia_size);
 
-	/* If inode_setattr's call to ext4_truncate failed to get a
-	 * transaction handle at all, we need to clean up the in-core
-	 * orphan list manually. */
+	if (!rc) {
+		setattr_copy(inode, attr);
+		mark_inode_dirty(inode);
+	}
+
+	/*
+	 * If the call to ext4_truncate failed to get a transaction handle at
+	 * all, we need to clean up the in-core orphan list manually.
+	 */
 	if (inode->i_nlink)
 		ext4_orphan_del(NULL, inode);