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>

1 files changed, 2 insertions, 10 deletions

diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c
index 7dee7b3..069620b 100644
--- a/fs/ext2/inode.c
+++ b/fs/ext2/inode.c
@@ -1156,15 +1156,10 @@ static void ext2_truncate_blocks(struct inode *inode, loff_t offset)
 	__ext2_truncate_blocks(inode, offset);
 }
 
-int ext2_setsize(struct inode *inode, loff_t newsize)
+static int ext2_setsize(struct inode *inode, loff_t newsize)
 {
-	loff_t oldsize;
 	int error;
 
-	error = inode_newsize_ok(inode, newsize);
-	if (error)
-		return error;
-
 	if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
 	    S_ISLNK(inode->i_mode)))
 		return -EINVAL;
@@ -1184,10 +1179,7 @@ int ext2_setsize(struct inode *inode, loff_t newsize)
 	if (error)
 		return error;
 
-	oldsize = inode->i_size;
-	i_size_write(inode, newsize);
-	truncate_pagecache(inode, oldsize, newsize);
-
+	truncate_setsize(inode, newsize);
 	__ext2_truncate_blocks(inode, newsize);
 
 	inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC;