fsnotify: fix list walk order

Marks were stored on the inode and vfsmonut mark list in order from
highest memory address to lowest memory address.  The code to walk those
lists thought they were in order from lowest to highest with
unpredictable results when trying to match up marks from each.  It was
possible that extra events would be sent to userspace when inode
marks ignoring events wouldn't get matched with the vfsmount marks.

This problem only affected fanotify when using both vfsmount and inode
marks simultaneously.

Signed-off-by: Eric Paris <eparis@redhat.com>
This commit is contained in:
Eric Paris 2010-08-27 21:24:24 -04:00
parent a2f13ad0ba
commit f72adfd540

View File

@ -261,27 +261,26 @@ int fsnotify(struct inode *to_tell, __u32 mask, void *data, int data_is,
while (inode_node || vfsmount_node) {
used_inode = used_vfsmount = false;
inode_group = vfsmount_group = NULL;
if (inode_node) {
inode_mark = hlist_entry(srcu_dereference(inode_node, &fsnotify_mark_srcu),
struct fsnotify_mark, i.i_list);
inode_group = inode_mark->group;
} else
inode_group = (void *)-1;
}
if (vfsmount_node) {
vfsmount_mark = hlist_entry(srcu_dereference(vfsmount_node, &fsnotify_mark_srcu),
struct fsnotify_mark, m.m_list);
vfsmount_group = vfsmount_mark->group;
} else
vfsmount_group = (void *)-1;
}
if (inode_group < vfsmount_group) {
if (inode_group > vfsmount_group) {
/* handle inode */
send_to_group(to_tell, NULL, inode_mark, NULL, mask, data,
data_is, cookie, file_name, &event);
used_inode = true;
} else if (vfsmount_group < inode_group) {
} else if (vfsmount_group > inode_group) {
send_to_group(to_tell, mnt, NULL, vfsmount_mark, mask, data,
data_is, cookie, file_name, &event);
used_vfsmount = true;