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, 14 insertions, 4 deletions

diff --git a/fs/ecryptfs/inode.c b/fs/ecryptfs/inode.c
index 31ef5252f0fe..82900b063b1e 100644
--- a/fs/ecryptfs/inode.c
+++ b/fs/ecryptfs/inode.c
@@ -804,10 +804,20 @@ static int truncate_upper(struct dentry *dentry, struct iattr *ia,
                 size_t num_zeros = (PAGE_CACHE_SIZE
                                     - (ia->ia_size & ~PAGE_CACHE_MASK));
 
+
+                /*
+                 * XXX(truncate) this should really happen at the begginning
+                 * of ->setattr.  But the code is too messy to that as part
+                 * of a larger patch.  ecryptfs is also totally missing out
+                 * on the inode_change_ok check at the beginning of
+                 * ->setattr while would include this.
+                 */
+                rc = inode_newsize_ok(inode, ia->ia_size);
+                if (rc)
+                        goto out;
+
                 if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
-                        rc = simple_setsize(inode, ia->ia_size);
-                        if (rc)
-                                goto out;
+                        truncate_setsize(inode, ia->ia_size);
                         lower_ia->ia_size = ia->ia_size;
                         lower_ia->ia_valid |= ATTR_SIZE;
                         goto out;
@@ -830,7 +840,7 @@ static int truncate_upper(struct dentry *dentry, struct iattr *ia,
                                 goto out;
                         }
                 }
-                simple_setsize(inode, ia->ia_size);
+                truncate_setsize(inode, ia->ia_size);
                 rc = ecryptfs_write_inode_size_to_metadata(inode);
                 if (rc) {
                         printk(KERN_ERR "Problem with "