Comment 0 for bug 474597

I have already reported this upstream. on ext4, fiemap will not report extents if the requested logical region of a file overlaps the extent less than blocksize. So, if you request star=0, len=100, you will get nothing.

I can provide example code, if you need.

ProblemType: Bug
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: leonard 2213 F.... pulseaudio
CRDA: Error: [Errno 2] No such file or directory
Card0.Amixer.info:
 Card hw:0 'Intel'/'HDA Intel at 0xf8400000 irq 20'
   Mixer name : 'Realtek ALC268'
   Components : 'HDA:10ec0268,14c00025,00100003 HDA:10573055,10573055,00100700'
   Controls : 16
   Simple ctrls : 13
Date: Wed Nov 4 20:10:06 2009
DistroRelease: Ubuntu 9.10
HibernationDevice: RESUME=UUID=ba65435a-214b-4e4e-9f46-7ced4d729ad0
MachineType: - N/A
NonfreeKernelModules: nvidia
Package: linux-image-2.6.31-14-generic 2.6.31-14.48
ProcCmdLine: root=UUID=423f8f68-484f-4773-94bf-da17f38c0dac ro rootfstype=ext4 quiet splash crashkernel=384M-2G:64M,2G-:128M
ProcEnviron:
 LANGUAGE=de_AT.UTF-8
 PATH=(custom, user)
 LANG=de_AT.UTF-8
 SHELL=/bin/bash
 LC_NUMERIC=en_US.UTF-8
ProcVersionSignature: Ubuntu 2.6.31-14.48-generic
RelatedPackageVersions:
 linux-backports-modules-2.6.31-14-generic 2.6.31-14.16
 linux-firmware 1.24
SourcePackage: linux
Uname: Linux 2.6.31-14-generic x86_64
WpaSupplicantLog:

dmi.bios.date: 12/31/2007
dmi.bios.vendor: COMPAL
dmi.bios.version: 1.16
dmi.board.name: IFL90
dmi.board.vendor: -
dmi.board.version: IFT00
dmi.chassis.asset.tag: -
dmi.chassis.type: 10
dmi.chassis.vendor: No Enclosure
dmi.chassis.version: N/A
dmi.modalias: dmi:bvnCOMPAL:bvr1.16:bd12/31/2007:svn-:pnN/A:pvrN/A:rvn-:rnIFL90:rvrIFT00:cvnNoEnclosure:ct10:cvrN/A:
dmi.product.name: N/A
dmi.product.version: N/A
dmi.sys.vendor: -