Andreas Dilger wrote: > On 2010-03-27, at 13:32, Eric Sandeen wrote: >> #13549, Kernel oops while online resizing of an ext4 filesystem >> >> if groups_per_flex < 2, sbi->s_flex_groups[] doesn't get filled out, >> and every other access to this first tests s_log_groups_per_flex; >> same thing needs to happen in resize or we'll wander off into >> a null pointer. > > Does it even make sense to set INCOMPAT_FLEX_BG if we only have a single > group per flexbg? That is just a normal filesystem then. That would be > a separate bug in mke2fs. yes, I really wondered about that, but we have this check throughout the ext4 kernel code right now, so as a quick fix ... (note in this case it was an ext3 fs converted to ext4, with tune2fs:) # tune2fs -O extents,uninit_bg,dir_index,flex_bg,huge_file,dir_nlink,extra_isize fsfile I haven't honestly looked at what it means to "turn on" flex_bg for a filesystem not originally mkfs'd with it. I'm not sure it does anything other than setting the flag, leaving flex group size == group size. Thanks, -Eric -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html