fix do_emergency_remount()/umount() races

need list_for_each_entry_safe() here.  Original didn't even
have restart logics, so if you race with umount() it blew up.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2010-03-22 20:11:53 -04:00
parent 6754af6464
commit e7fe0585ca

View file

@ -602,10 +602,10 @@ int do_remount_sb(struct super_block *sb, int flags, void *data, int force)
static void do_emergency_remount(struct work_struct *work)
{
struct super_block *sb;
struct super_block *sb, *n;
spin_lock(&sb_lock);
list_for_each_entry(sb, &super_blocks, s_list) {
list_for_each_entry_safe(sb, n, &super_blocks, s_list) {
if (list_empty(&sb->s_instances))
continue;
sb->s_count++;
@ -618,8 +618,8 @@ static void do_emergency_remount(struct work_struct *work)
do_remount_sb(sb, MS_RDONLY, NULL, 1);
}
up_write(&sb->s_umount);
put_super(sb);
spin_lock(&sb_lock);
__put_super(sb);
}
spin_unlock(&sb_lock);
kfree(work);