Hi. Max. I have a question. Your mmc host driver set to host->max_discard_to by some value instead of not zero ?
Thanks. 2013/4/5, Max Filippov <jcmvb...@gmail.com>: > On Fri, Apr 5, 2013 at 5:53 AM, Shaohua Li <s...@kernel.org> wrote: >> On Thu, Apr 04, 2013 at 06:00:18AM +0400, Max Filippov wrote: > > [...] > >>> the commit 0cfbcafcae8b7364b5fa96c2b26ccde7a3a296a9 'block: add plug >>> for blkdev_issue_discard' >>> have added merge opportunity for DISCARD requests. When I do >>> mkfs.f2fs on a 5G partition (0xad8000 sectors) it submits two bios, >>> one for 0x7fe000 sectors (0xffc00000 bytes) and another for >>> 0x2da000 sectors (0x5b400000 bytes). Prior to that commit these >>> bios weren't merged into one request. Now the second bio gets >>> merged with the first, but the request's __data_len field is unsigned >>> int >>> and it gets wrapped to 0x5b000000 bytes instead of 0x15b000000 >>> in the bio_attempt_back_merge. Later this reduced size is passed to >>> the blk_update_request causing KERN_ERR and not completed >>> request. Reverting this commit fixes mkfs.f2fs for me. >> >> A workaround is setting limits.max_discard_sectors to a smaller value. > > I'm not sure: > 1) in my case max_discard_sectors is 0x7fe000 (0xffc00000 bytes, > which still fits into 32 bits) and > 2) this parameter will only change size of individual discard requests for > the discarded range, but as long as these requests are done inside > the plug they will be merged anyway with an overflow if we try > to discard more than 4G at once. > >> So the question is why __data_len isn't sector based? Since disk is >> sector >> based, is there any disk finishing IO in byte granularity? Maybe Jens can >> answer. > > -- > Thanks. > -- Max > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majord...@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/