NeilBrown <neilb@xxxxxxx> wrote: > > If md is asked to store a bitmap in a file, it tries to hold onto the > page cache pages for that file, manipulate them directly, and call a > cocktail of operations to write the file out. I don't believe this is > a supportable approach. erk. I think it's better than... > This patch changes the approach to use the same approach as swap files. > i.e. bmap is used to enumerate all the block address of parts of the file > and we write directly to those blocks of the device. That's going in at a much lower level. Even swapfiles don't assume buffer_heads. When playing with bmap() one needs to be careful that nobody has truncated the file on you, else you end up writing to disk blocks which aren't part of the file any more. All this (and a set_fs(KERNEL_DS), ug) looks like a step backwards to me. Operating at the pagecache a_ops level looked better, and more filesystem-independent. I haven't looked at this patch at all closely yet. Do I really need to? - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
