Hi, I can not find the patch - attempt to fix race in bigalloc code path - in the mailing list. I don't think this patch can work. set_buffers_da_mapped() is called under i_data_sem, so it can not lock page. If the page is not locked, calling page_has_buffers() is not secure as Jan pointed out previously. If a page is partially mapped(block size < page size), setting BH_Da_Mapped without locking page is not safe too. BTW: find_delalloc_range() does not lock page as ext4_fiemap_cb(). As Jan said, it can crash system. BUT we can not lock page in both scenarios, because i_data_sem is hold. So delayed extent list is necessary. I have finished the code implementing delayed extent list, which needs some further testing. What are your opinions? -- Best Wishes Yongqiang Yang -- 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
