Hi, While looking at a bug related to direct IO returns to EIO, after looking at the code, I found there is a window that try_to_free_buffers() from direct IO could race with JBD, which holds the reference to the data buffers before journal_commit_transaction() ensures the data buffers has reached to the disk. A little more detail: to prepare for direct IO, generic_file_direct_IO() calls invalidate_inode_pages2_range() to invalidate the pages in the cache before performaning direct IO. invalidate_inode_pages2_range() tries to free the buffers via try_to free_buffers(), but sometimes it can't, due to the buffers is possible still on some transaction's t_sync_datalist or t_locked_list waiting for journal_commit_transaction() to process it. Currently Direct IO simply returns EIO if try_to_free_buffers() finds the buffer is busy, as it has no clue that JBD is referencing it. Is this a known issue and expected behavior? Any thoughts? Mingming -- 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
