resize: File too large

Hello,

I met a problem when resize btrfs as follows. The btrfs related sysinfo is attached at the end of this mail[1].

$ dd if=/dev/zero of=btrfs_5gb.img bs=1024 count=5000000 

$ mkfs.btrfs btrfs_5gb.img  

$ sudo mkdir -p /mnt/btrfs_5gb 

$ mount -t btrfs btrfs_5gb.img /mnt/btrfs_5gb 

$ btrfs filesystem resize +10g /mnt/btrfs_5gb  
Resize '/mnt/btrfs_5gb' of '+10g' 
ERROR: unable to resize '/mnt/btrfs_5gb' - File too large 

Is it a misuse case of resize?

And I expected not the message "File too large" but different error message.

Thanks.

Sincerely yours,
Taeha Kim,
Senior Engineer, Samsung Electronics

[1] The btrfs related sysinfo

$ btrfs --version
btrfs-progs v4.1.2

$ uname -r
4.0.8-300.fc22.x86_64

$ btrfs fi show /mnt/btrfs_5g
btrfs-progs v4.1

$ btrfs fi df /mnt/btrfs_5g
Data, single: total=8.00MiB, used=64.00KiB
System, DUP: total=8.00MiB, used=16.00KiB
System, single: total=4.00MiB, used=0.00B
Metadata, DUP: total=244.12MiB, used=112.00KiB
Metadata, single: total=8.00MiB, used=0.00B
GlobalReserve, single: total=16.00MiB, used=0.00B

$ dmesg | grep BTRFS
BTRFS info (device loop0): disk space caching is enabled
BTRFS: has skinny extents
BTRFS: flagging fs with big metadata feature
BTRFS: creating UUID tree
BTRFS info (device loop0): disk space caching is enabled
BTRFS: has skinny extents.

Hi, Taeha Kim

Thanks for reporting above problem.

Kernel return -EFBIG in this case(dev not big enouth),
and btrfs-progs output corresponding standard error message for this return value:
"File too large"

This message is almost right for most case, but not for resize.

Good suggestion, I will change it to some accurate description.

Thanks
Zhaolei