https://github.com/torvalds/linux
Revision cd02dca56442e1504fd6bc5b96f7f1870162b266 authored by Chris Mason on 13 December 2010, 19:56:23 UTC, committed by Chris Mason on 14 December 2010, 01:06:52 UTC
When we mount in RAID degraded mode without adding a new device to
replace the failed one, we can end up using the wrong RAID flags for
allocations.

This results in strange combinations of block groups (raid1 in a raid10
filesystem) and corruptions when we try to allocate blocks from single
spindle chunks on drives that are actually missing.

The first device has two small 4MB chunks in it that mkfs creates and
these are usually unused in a raid1 or raid10 setup.  But, in -o degraded,
the allocator will fall back to these because the mask of desired raid groups
isn't correct.

The fix here is to count the missing devices as we build up the list
of devices in the system.  This count is used when picking the
raid level to make sure we continue using the same levels that were
in place before we lost a drive.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
1 parent 68433b7
Raw File
Tip revision: cd02dca56442e1504fd6bc5b96f7f1870162b266 authored by Chris Mason on 13 December 2010, 19:56:23 UTC
Btrfs: account for missing devices in RAID allocation profiles
Tip revision: cd02dca
REPORTING-BUGS
[Some of this is taken from Frohwalt Egerer's original linux-kernel FAQ]

     What follows is a suggested procedure for reporting Linux bugs. You
aren't obliged to use the bug reporting format, it is provided as a guide
to the kind of information that can be useful to developers - no more.

     If the failure includes an "OOPS:" type message in your log or on
screen please read "Documentation/oops-tracing.txt" before posting your
bug report. This explains what you should do with the "Oops" information
to make it useful to the recipient.

      Send the output to the maintainer of the kernel area that seems to
be involved with the problem, and cc the relevant mailing list. Don't
worry too much about getting the wrong person. If you are unsure send it
to the person responsible for the code relevant to what you were doing.
If it occurs repeatably try and describe how to recreate it. That is
worth even more than the oops itself.  The list of maintainers and
mailing lists is in the MAINTAINERS file in this directory.  If you
know the file name that causes the problem you can use the following
command in this directory to find some of the maintainers of that file:
     perl scripts/get_maintainer.pl -f <filename>

      If it is a security bug, please copy the Security Contact listed
in the MAINTAINERS file.  They can help coordinate bugfix and disclosure.
See Documentation/SecurityBugs for more information.

      If you are totally stumped as to whom to send the report, send it to
linux-kernel@vger.kernel.org. (For more information on the linux-kernel
mailing list see http://www.tux.org/lkml/).

This is a suggested format for a bug report sent to the Linux kernel mailing
list. Having a standardized bug report form makes it easier for you not to
overlook things, and easier for the developers to find the pieces of
information they're really interested in. Don't feel you have to follow it.

      First run the ver_linux script included as scripts/ver_linux, which
reports the version of some important subsystems.  Run this script with
the command "sh scripts/ver_linux".

Use that information to fill in all fields of the bug report form, and
post it to the mailing list with a subject of "PROBLEM: <one line
summary from [1.]>" for easy identification by the developers.

[1.] One line summary of the problem:
[2.] Full description of the problem/report:
[3.] Keywords (i.e., modules, networking, kernel):
[4.] Kernel information
[4.1.] Kernel version (from /proc/version):
[4.2.] Kernel .config file:
[5.] Most recent kernel version which did not have the bug:
[6.] Output of Oops.. message (if applicable) with symbolic information
     resolved (see Documentation/oops-tracing.txt)
[7.] A small shell script or example program which triggers the
     problem (if possible)
[8.] Environment
[8.1.] Software (add the output of the ver_linux script here)
[8.2.] Processor information (from /proc/cpuinfo):
[8.3.] Module information (from /proc/modules):
[8.4.] Loaded driver and hardware information (/proc/ioports, /proc/iomem)
[8.5.] PCI information ('lspci -vvv' as root)
[8.6.] SCSI information (from /proc/scsi/scsi)
[8.7.] Other information that might be relevant to the problem
       (please look in /proc and include all information that you
       think to be relevant):
[X.] Other notes, patches, fixes, workarounds:


Thank you
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