On Thu, Jan 03, 2014 at 19:49, Eric Sandeen wrote > > On 1/3/14, 12:45 PM, Juergens Dirk (CM-AI/ECO2) wrote: > > > > On Thu, Jan 03, 2014 at 19:24, Eric Sandeen wrote > >> > >> On 1/3/14, 10:29 AM, Juergens Dirk (CM-AI/ECO2) wrote: > >>> So, I think there _might_ be a kernel bug, but it could be also a > >> problem > >>> related to the particular type of eMMC. We did not observe the same > >> issue > >>> in previous tests with another type of eMMC from another supplier, > >> but this > >>> was with an older kernel patch level and with another HW design. > >>> > >>> Regarding a possible kernel bug: Is there any chance that the > invalid > >>> ee_len or ee_start are returned by, e.g., the block allocator ? > >>> If so, can we try to instrument the code to get suitable traces ? > >>> Just to see or to exclude that the corrupted inode is really > written > >>> to the eMMC ? > >> > >> From your description it does sound possible that it's a kernel bug. > >> Adding testcases to the code to catch it before it hits the journal > >> might be helpful - but then maybe this is something getting > overwritten > >> after the fact - hard to say. > >> > >> Can you share more details of the test you are running? Or maybe > even > >> the test itself? > > > > Yes, for sure, we can. Weller, please provide additional details > > or corrections. > > > > In short: > > Basically we use an automated cyclic test writing many small > > (some kBytes) files with CRC checksums for easy consistency check > > into a separate test partition. Files also contain meta information > > like filename, sequence number and a random number to allow to > identify > > from block device image dumps, if we just see a fragment of an old > > deleted file or a still valid one. > > > > Each test loop looks like this: > > 0) mkfs the filesystem - with what options? How big? Here we do need the details from Weller, cause he has done all this. > > > 1) Boot the device after power on or reset > > 2) Do fsck -n BEFORE mounting > > 2 a) (optional) binary dump of the journal > > 3) Mount test partition > > Again with what options, if any? Details again have to be given by Weller, sorry. > > > 4) File content check for all files from prev. loop > > 5) erase all files from previous loop > > 6) start writing hundreds/thousands of test files > > in multiple directories with several threads > > I guess this is where we might need more details in order, > to try to recreate the failure, but perhaps > this is not a case where you can simply share the IO > generation utility...? I think we can share the code, please let me check on Monday. > > Thanks, > -Eric > > > 7) after random time cut the power or do soft reset > > > > If 2), 3), 4) or 5) fails, stop test. > > > > We are running the test usually with kind of transaction > > safe handling, i.e. use fsync/rename, to avoid zero length files > > or file fragments. > > > >> > >> I've used a test framework in the past to simulate resets w/o > needing > >> to reset the box, and do many journal replays very quickly. It'd be > >> interesting to run it using your testcase. > >> > >> Thanks, > >> -Eric > > > > Mit freundlichen Grüßen / Best regards > > > > Dirk Juergens > > > > Robert Bosch Car Multimedia GmbH > > Mit freundlichen Grüßen / Best regards Dirk Juergens Robert Bosch Car Multimedia GmbH -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
