Hi Ted, On Thu, 3 Jul 2014 09:43:38 -0400 "Theodore Ts'o" <tytso@xxxxxxx> wrote: > On Tue, Jul 01, 2014 at 10:55:11AM +0200, Matteo Croce wrote: > > 2014-07-01 10:42 GMT+02:00 Darrick J. Wong <darrick.wong@xxxxxxxxxx>: > > > > I have a Samsung SSD 840 PRO > > Matteo, > > For you, you said you were seeing these problems on 3.15. Was it > *not* happening for you when you used an older kernel? If so, that > would help us try to provide the basis of trying to do a bisection > search. I also tested with 3.15, and there too I see the same problem. > Using the kvm-xfstests infrastructure, I've been trying to reproduce > the problem as follows: > > ./kvm-xfstests --no-log -c 4k generic/075 ; e2fsck -p /dev/heap/test-4k ; e2fsck -f /dev/heap/test-4k > > xfstests geneeric/075 runs fsx which does a fair amount of block > allocation deallocations, and then after the test finishes, it first > replays the journal (e2fsck -p) and then forces a fsck run on the > test disk that I use for the run. > > After I launch this, in a separate window, I do this: > > sleep 60 ; killall qemu-system-x86_64 > > This kills the qemu process midway through the fsx test, and then I > see if I can find a problem. I haven't had a chance to automate this > yet, and it is my intention to try to set this up where I can run this > on a ramdisk or a SSD, so I can more closely approximate what people > are reporting on flash-based media. > > So far, I haven't been able to reproduce the problem. If after doing > a large number of times, it can't be reproduced (especially if it > can't be reproduced on an SSD), then it would lead us to believe that > one of two things is the cause. (a) The CACHE FLUSH command isn't > properly getting sent to the device in some cases, or (b) there really > is a hardware problem with the flash device in question. Could (a) be caused by a bug in the mmc subsystem or in the MMC peripheral driver? Can you explain why I don't see any problems with EXT3? I can't discard the possibility of (b) because I cannot prove it, but I will try to see if I can do the same test on a SSD which I happen to have on that platform. That should be able to rule out problems with the eMMC chip and -driver, right? Do you know a way to investigate (a) (CACHE FLUSH not being sent correctly)? I left the system running (it started from a dirty EXT4 partition), and I am seen the following error pop up after a few minutes. The system is not doing much (some syslog activity maybe, but not much more): [ 303.072983] EXT4-fs (mmcblk1p2): error count: 4 [ 303.077558] EXT4-fs (mmcblk1p2): initial error at 1404216838: ext4_mb_generate_buddy:756 [ 303.085690] EXT4-fs (mmcblk1p2): last error at 1404388969: ext4_mb_generate_buddy:757 What does that mean? Best regards, -- David Jander Protonic Holland. -- 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
