On Fri, Sep 26 2003, Steven Dake wrote: > Folks, > Thanks Matt and Jens for the debug help on the multipath problem. I now > have a patch (attached) which solves the problem and makes multipath > work properly. There are two types of "flags" that are used in a block > io request, bi_flags, and bi_rw. bi_flags is used for flags to the > block level code, and bi_rw is used for flags to the low level device > drivers. The code in the multipath driver used the wrong flag in the > wrong field. In this case, the flag FASTFAIL (value 3) was being set to > the bi_flags field. FASTFAIL is a hint to the low level driver that it > should try to fail out quickly. Unfortunately, the value 3 is also > BIO_SEG_VALID, which is a flag to the block subsystem that the segments > shouldn't be recalculated. The result was that the wrong field was set, > telling the block layer not to recalculate the segments resulting in > phys and hw segments of 0. Not good. > > Neil can you send upstream ? Auch good catch! I'm sorry to say this is actually my fault... -- Jens Axboe - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
