Messages in this thread |  | | From | Andreas Dilger <> | Subject | Re: [PATCH] Re: [bug] infinite loop in generic_make_request() | Date | Thu, 30 Nov 2000 13:05:53 -0700 (MST) |
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Neil Brown write: > On Thursday November 30, ganesh@veritas.com wrote: > > in generic_make_request(), the following code handles stacking: > > > > do { > > q = blk_get_queue(bh->b_rdev); > > if (!q) { > > printk(...) > > buffer_IO_error(bh); > > break; > > } > > } while (q->make_request_fn(q, rw, bh)); > > > > however, make_request_fn may return -1 in case of errors. one such fn is > > raid0_make_request(). this causes generic_make_request() to loop endlessly. > > lvm returns 1 unconditionally, so it would also loop if an error occured in > > lvm_map(). other bdevs might have the same problem. > > I think a better mechanism would be to mandate that make_request_fn ought > > to call bh->b_end_io() in case of errors and return 0. > > Good catch, thanks. Below is a patch to fix md drivers (md.c, > linear.c and raid0.c). > > NeilBrown
You need to also patch the lvm.c driver at the same time... However, this change now makes it very counter-intuitive compared to other kernel functions. Normally, we return 0 on success, and -ve on error. Maybe the RAID and LVM make_request functions should be changed to do that instead (i.e. 0 on success, -ve on error, and maybe "1" if they do their own recursion to break the loop)?
Cheers, Andreas
PS - I fixed the LVM mailing list address... -- Andreas Dilger \ "If a man ate a pound of pasta and a pound of antipasto, \ would they cancel out, leaving him still hungry?" http://www-mddsp.enel.ucalgary.ca/People/adilger/ -- Dogbert - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org Please read the FAQ at http://www.tux.org/lkml/
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