On Wed, May 11, 2011 at 12:24:58AM +0900, OGAWA Hirofumi wrote: > > under writeback and when it's freed no writeback is started. > > Sure for data -> data reallocated case. metadata -> data/metadata is > still there. That's usually handled differently. For XFS take a look at the xfs_alloc_busy_* function. For 2.6.40 they've been mostly rewritten to rarely wait for the reuse but instead avoid busy blocks. But that's a real data integrity issue even without stable pages for I/O. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>