On Tue, Jun 26, 2012 at 10:55 AM, Jeff Moyer <[email protected]> wrote: > Hi, > > This commit: > > commit 080399aaaf3531f5b8761ec0ac30ff98891e8686 > Author: Jeff Moyer <[email protected]> > Date: Fri May 11 16:34:10 2012 +0200 > > block: don't mark buffers beyond end of disk as mapped > > exposed a bug in __getblk_slow that causes mount to hang as it loops > infinitely waiting for a buffer that lies beyond the end of the disk to > become uptodate. The problem was initially reported by Torsten Hilbrich > here: https://lkml.org/lkml/2012/6/18/54, and also reported > independently here: > http://www.sysresccd.org/forums/viewtopic.php?f=13&t=4511, and then > Richard W.M. Jones and Marcos Mello noted a few separate bugzillas also > associated with the same issue. > > The main problem is here, in __getblk_slow: > > for (;;) { > struct buffer_head * bh; > int ret; > > bh = __find_get_block(bdev, block, size); > if (bh) > return bh; > > ret = grow_buffers(bdev, block, size); > if (ret < 0) > return NULL; > if (ret == 0) > free_more_memory(); > } > > __find_get_block does not find the block, since it will not be marked as > mapped, and so grow_buffers is called to fill in the buffers for the > associated page. I believe the for (;;) loop is there primarily to > retry in the case of memory pressure keeping grow_buffers from > succeeding. However, we also continue to loop for other cases, like the > block lying beond the end of the disk. So, the fix I came up with is to > only loop when grow_buffers fails due to memory allocation issues > (return value of 0). > > The attached patch was tested by myself, Torsten, and Rich, and was > found to resolve the problem in call cases. > > Comments, as always, are appreciated.
Is this needed in addition to your earlier patch here: http://article.gmane.org/gmane.linux.kernel/1316228 or is it a replacement for that? josh -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
