check ATTR_SIZE contraints in inode_change_ok

Make sure we check the truncate constraints early on in ->setattr by adding
those checks to inode_change_ok.  Also clean up and document inode_change_ok
to make this obvious.

As a fallout we don't have to call inode_newsize_ok from simple_setsize and
simplify it down to a truncate_setsize which doesn't return an error.  This
simplifies a lot of setattr implementations and means we use truncate_setsize
almost everywhere.  Get rid of fat_setsize now that it's trivial and mark
ext2_setsize static to make the calling convention obvious.

Keep the inode_newsize_ok in vmtruncate for now as all callers need an
audit for its removal anyway.

Note: setattr code in ecryptfs doesn't call inode_change_ok at all and
needs a deeper audit, but that is left for later.

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

2 files changed, 4 insertions, 6 deletions

diff --git a/fs/gfs2/aops.c b/fs/gfs2/aops.c
index 703000d..54fe087 100644
--- a/fs/gfs2/aops.c
+++ b/fs/gfs2/aops.c
@@ -702,12 +702,12 @@ out:
 	page_cache_release(page);
 
 	/*
-	 * XXX(hch): the call below should probably be replaced with
+	 * XXX(truncate): 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)
-		simple_setsize(&ip->i_inode, ip->i_inode.i_size);
+		truncate_setsize(&ip->i_inode, ip->i_inode.i_size);
 out_endtrans:
 	gfs2_trans_end(sdp);
 out_trans_fail:
diff --git a/fs/gfs2/ops_inode.c b/fs/gfs2/ops_inode.c
index d7d410a..1009be2 100644
--- a/fs/gfs2/ops_inode.c
+++ b/fs/gfs2/ops_inode.c
@@ -1072,7 +1072,7 @@ int gfs2_permission(struct inode *inode, int mask)
 }
 
 /*
- * XXX: should be changed to have proper ordering by opencoding simple_setsize
+ * XXX(truncate): the truncate_setsize calls should be moved to the end.
  */
 static int setattr_size(struct inode *inode, struct iattr *attr)
 {
@@ -1084,10 +1084,8 @@ static int setattr_size(struct inode *inode, struct iattr *attr)
 		error = gfs2_trans_begin(sdp, 0, sdp->sd_jdesc->jd_blocks);
 		if (error)
 			return error;
-		error = simple_setsize(inode, attr->ia_size);
+		truncate_setsize(inode, attr->ia_size);
 		gfs2_trans_end(sdp);
-		if (error) 
-			return error;
 	}
 
 	error = gfs2_truncatei(ip, attr->ia_size);