Date: Sun, 01 Dec 2019 17:17:03 +0000 From: bugzilla-noreply@freebsd.org To: bugs@FreeBSD.org Subject: [Bug 242341] GEOM / GEOM_PART: silent discard MBR modification Message-ID: <bug-242341-227@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D242341 Bug ID: 242341 Summary: GEOM / GEOM_PART: silent discard MBR modification Product: Base System Version: 12.1-RELEASE Hardware: Any OS: Any Status: New Severity: Affects Only Me Priority: --- Component: kern Assignee: bugs@FreeBSD.org Reporter: tomek@cedro.info Hello world, I am unable to clone a pendrive with `dd if=3D/dev/da0 of=3D/dev/da1` becau= se GEOM_PART considers disk broken and silently prevents writing _all_ data (it discards MBR), thus: 1. OS / GEOM is hiding things from operator. It does not write bytes as instructed to fix the disk, instead, it considers disk invalid and silently discards _only_some_of_the_data_ with no clear error/warning indication. Unacceptable!!! 2. OS / GEOM lies to operator. It does return a SUCCESS code while _some_ data goes to /dev/null. Unacceptale!!! 3. If disk is _considered_ broken then access should be _fully_ blocked. But how am I supposed to fix it when OS silently blocks essential part of the fix? Who allows writing over a corrupted disk anyway? This looks typical Linux way, and we don't really like Linux for th= at, right? 4. OS / GEOM is broken and incoherent in this area and proves system unreliable / not trustworthy. This needs to be fixed please. Solution proposal: 1. Do not hide actions / never lie to the user. Do what superuser wants. 2. When disk is _considered_ broken then access should be blocked returning= I/O Error with DMESG message and instructions how to use sysctl that will allow writing to a _whole_ disk in order to fix it. 3. Use clear _warnings_ but perform actions, or use _errors_ and prevent actions. Thank you :-) Tomek ugen0.8: <Kingston DataTraveler 3.0> at usbus0 umass1 on uhub0 umass1: <Kingston DataTraveler 3.0, class 0/0, rev 3.20/1.10, addr 7> on us= bus0 umass1: SCSI over Bulk-Only; quirks =3D 0x8100 umass1:3:1: Attached to scbus3 da1 at umass-sim1 bus 1 scbus3 target 0 lun 0 da1: <Kingston DataTraveler 3.0 PMAP> Removable Direct Access SPC-4 SCSI de= vice da1: Serial Number BLAHBLAH da1: 400.000MB/s transfers da1: 118272MB (242221056 512 byte sectors) da1: quirks=3D0x2<NO_6_BYTE> GEOM_PART: integrity check failed (da1, MBR) <--- here is the only problem indication --=20 You are receiving this mail because: You are the assignee for the bug.=
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