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, 1 insertions, 5 deletions

diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index 43a9b3730a98..3978a42d4f04 100644
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -1280,12 +1280,8 @@ static int fuse_do_setattr(struct dentry *entry, struct iattr *attr,
         if ((attr->ia_valid & ATTR_OPEN) && fc->atomic_o_trunc)
                 return 0;
 
-        if (attr->ia_valid & ATTR_SIZE) {
-                err = inode_newsize_ok(inode, attr->ia_size);
-                if (err)
-                        return err;
+        if (attr->ia_valid & ATTR_SIZE)
                 is_truncate = true;
-        }
 
         req = fuse_get_req(fc);
         if (IS_ERR(req))