15.07.2016 00:20, Chris Mason пишет: > > > On 07/12/2016 05:50 PM, Goffredo Baroncelli wrote: >> Hi All, >> >> I developed a new btrfs command "btrfs insp phy"[1] to further >> investigate this bug [2]. Using "btrfs insp phy" I developed a script >> to trigger the bug. The bug is not always triggered, but most of time >> yes. >> >> Basically the script create a raid5 filesystem (using three >> loop-device on three file called disk[123].img); on this filesystem
Are those devices themselves on btrfs? Just to avoid any sort of possible side effects? >> it is create a file. Then using "btrfs insp phy", the physical >> placement of the data on the device are computed. >> >> First the script checks that the data are the right one (for data1, >> data2 and parity), then it corrupt the data: >> >> test1: the parity is corrupted, then scrub is ran. Then the (data1, >> data2, parity) data on the disk are checked. This test goes fine all >> the times >> >> test2: data2 is corrupted, then scrub is ran. Then the (data1, data2, >> parity) data on the disk are checked. This test fail most of the time: >> the data on the disk is not correct; the parity is wrong. Scrub >> sometime reports "WARNING: errors detected during scrubbing, >> corrected" and sometime reports "ERROR: there are uncorrectable >> errors". But this seems unrelated to the fact that the data is >> corrupetd or not >> test3: like test2, but data1 is corrupted. The result are the same as >> above. >> >> >> test4: data2 is corrupted, the the file is read. The system doesn't >> return error (the data seems to be fine); but the data2 on the disk is >> still corrupted. >> >> >> Note: data1, data2, parity are the disk-element of the raid5 stripe- >> >> Conclusion: >> >> most of the time, it seems that btrfs-raid5 is not capable to rebuild >> parity and data. Worse the message returned by scrub is incoherent by >> the status on the disk. The tests didn't fail every time; this >> complicate the diagnosis. However my script fails most of the time. > > Interesting, thanks for taking the time to write this up. Is the > failure specific to scrub? Or is parity rebuild in general also failing > in this case? > How do you rebuild parity without scrub as long as all devices appear to be present? -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
