> On 2016/07/06 18:52, Lukas Herbolt wrote: >> Hi, >> Yes this part is wrong and reads are not dropped. >> I have a patch ready, just have to send it out. btw, is this fix going to be included in the next release? On 2016/07/06 21:54, Akira Hayakawa wrote: > Thanks, > > I want the patch in the main-tree quickly. > Because without it, my tests will not be green. > This is really annoying. > > I made a quick reproducer of this problem. > If you are looking for one, this will help. > (You need to install sbt first) > > https://github.com/akiradeveloper/writeboost-test-suite > > test("flakey (read)") { > Memory(Sector.M(16)) { a => > Flakey.Table(a, 0, 1).create { b => > intercept[Exception] { > Shell(s"dd status=none if=${b.bdev.path} iflag=direct of=/dev/null") > } > } > } > } > > $ sudo sbt "testOnly dmtest.FlakeyTest" > 12:44:00.643 [pool-2-thread-3-ScalaTest-running-FlakeyTest] INFO dmtest - [TEST] flakey (read) > 12:44:00.752 [pool-2-thread-3-ScalaTest-running-FlakeyTest] DEBUG dmtest - reload: table=0 32768 flakey /dev/loop0 0 0 1 > [info] FlakeyTest: > [info] - flakey (read) *** FAILED *** > [info] Expected exception java.lang.Exception to be thrown, but no exception was thrown. (FlakeyTest.scala:9) > [info] Run completed in 2 seconds, 781 milliseconds. > [info] Total number of tests run: 1 > [info] Suites: completed 1, aborted 0 > [info] Tests: succeeded 0, failed 1, canceled 0, ignored 0, pending 0 > > - Akira > > On 2016/07/06 18:52, Lukas Herbolt wrote: >> Hi, >> Yes this part is wrong and reads are not dropped. >> I have a patch ready, just have to send it out. >> >> Lukas >> >> On Wed, Jul 6, 2016 at 8:33 AM, Akira Hayakawa <ruby.wktk@xxxxxxxxx> wrote: >> >>> Hi, >>> >>> I am using dm-flakey to emulate a broken device that should return -EIO on >>> both read and write. >>> I use the parameter up_interval=0 and down_interval=1. >>> >>> But when I am dd-ing the flakey device, while write fails, read succeeds. >>> This isn't the behavior I expect. >>> >>> Then I looked into the code. >>> >>> 326 static int flakey_end_io(struct dm_target *ti, struct bio *bio, int >>> error) >>> 327 { >>> 328 struct flakey_c *fc = ti->private; >>> 329 struct per_bio_data *pb = dm_per_bio_data(bio, sizeof(struct >>> per_bio_data)); >>> 330 >>> 331 /* >>> 332 * Corrupt successful READs while in down state. >>> 333 * If flags were specified, only corrupt those that match. >>> 334 */ >>> 335 if (fc->corrupt_bio_byte && !error && pb->bio_submitted && >>> 336 (bio_data_dir(bio) == READ) && (fc->corrupt_bio_rw == >>> READ) && >>> 337 all_corrupt_bio_flags_match(bio, fc)) >>> 338 corrupt_bio_data(bio, fc); >>> 339 >>> 340 return error; >>> 341 } >>> >>> When the bio direction is READ and currupt_bio_bytes isn't specified >>> the READ bio is handled normally right? >>> >>> I think READ requests should return -EIO if >>> >>> 1. corrupt_bio_bytes isn't specified >>> 2. but the requested is handled during down interval. >>> >>> as well as WRITE requests: >>> >>> 305 /* >>> 306 * Corrupt matching writes. >>> 307 */ >>> 308 if (fc->corrupt_bio_byte && (fc->corrupt_bio_rw == >>> WRITE)) { >>> 309 if (all_corrupt_bio_flags_match(bio, fc)) >>> 310 corrupt_bio_data(bio, fc); >>> 311 goto map_bio; >>> 312 } >>> 313 >>> 314 /* >>> 315 * By default, error all I/O. >>> 316 */ >>> 317 return -EIO; >>> 318 } >>> >>> This code is similar to what we see in the end_io. >>> >>> If my understanding is correct, I would like to modify dm-flakey to return >>> -EIO in the end_io. >>> >>> I would like to request for comments. >>> >>> Thanks, >>> >>> - Akira >>> >>> -- >>> dm-devel mailing list >>> dm-devel@xxxxxxxxxx >>> https://www.redhat.com/mailman/listinfo/dm-devel >>> >> >> >> -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
