On 08/15/2011 05:03 PM, Michael Tokarev wrote: > 15.08.2011 12:56, Michael Tokarev пишет: >> 15.08.2011 12:00, Michael Tokarev wrote: >> [....] >> >> So, it looks like this (starting with cold cache): >> >> 1. rename the redologs and copy them over - this will >> make a hot copy of redologs >> 2. startup oracle - it will complain that the redologs aren't >> redologs, the header is corrupt >> 3. shut down oracle, start it up again - it will succeed. >> >> If between 1 and 2 you'll issue sync(1) everything will work. >> When shutting down, oracle calls fsync(), so that's like >> sync(1) again. >> >> If there will be some time between 1. and 2., everything >> will work too. >> >> Without dioread_nolock I can't trigger the problem no matter >> how I tried. >> >> >> A smaller test case. I used redo1.odf file (one of the >> redologs) as a test file, any will work. >> >> $ cp -p redo1.odf temp >> $ dd if=temp of=foo iflag=direct count=20 >> >> Now, first 512bytes of "foo" will contain all zeros, while >> the beginning of redo1.odf is _not_ zeros. >> >> Again, without aioread_nolock it works as expected. >> >> >> And the most important note: without the patch there's no >> data corruption like that. But instead, there is the >> lockup... ;) > > Actually I can reproduce this data corruption without the > patch too, just not that easily. Oracle testcase (with > copying redologs over) does that nicely. So that's a > separate bug which was here before. cool, thanks for the test. btw, I can reproduce the bug with $ cp -p redo1.odf temp $ dd if=temp of=foo iflag=direct count=20 Not that easy, but I did encounter one during my more than 20 tries, hope I can get something out soon. Thanks Tao -- 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
