du -h reports wrong file size on DrvFs

[marcogroppo]

• A brief description

du -h (du --block-size=human-readable) does not work correctly on DrvFs volumes (i.e., /mnt/c).

• Expected results

If the file size is ~10M du -h should output 10M.

• Actual results (with terminal output if applicable)

Totally wrong file size (for example 5 GB for a 10 MB file!)

• Your Windows build number

Windows 10 Creators Update
Windows 10 Pro Version 1703 Build 15063.138

• Steps / All commands required to reproduce the error from a brand new installation

$ dd if=/dev/zero of=test.bin bs=1M count=10
10+0 records in
10+0 records out
10485760 bytes (10 MB, 10 MiB) copied, 0.049809 s, 211 MB/s
$ ls -l test.bin
-rwxrwxrwx 1 root root 10485760 Apr 12 18:06 test.bin
$ du -h test.bin
5.1G    test.bin

The command works fine on VolFs:

$ mv test.bin ~/
$ cd
$ du -h test.bin
10M     test.bin

• Strace of the failing command

execve("/usr/bin/du", ["du", "-h", "test.bin"], [/* 16 vars */]) = 0
brk(NULL)                               = 0x7f0000
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f2c3f740000
access("/etc/ld.so.preload", R_OK)      = -1 ENOENT (No such file or directory)
open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=20599, ...}) = 0
mmap(NULL, 20599, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f2c3f745000
close(3)                                = 0
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
open("/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0P\t\2\0\0\0\0\0"..., 832) = 832
fstat(3, {st_mode=S_IFREG|0755, st_size=1864888, ...}) = 0
mmap(NULL, 3967392, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f2c3f030000
mprotect(0x7f2c3f1ef000, 2097152, PROT_NONE) = 0
mmap(0x7f2c3f3ef000, 24576, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x1bf000) = 0x7f2c3f3ef000
mmap(0x7f2c3f3f5000, 14752, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x7f2c3f3f5000
close(3)                                = 0
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f2c3f730000
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f2c3f720000
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f2c3f710000
arch_prctl(ARCH_SET_FS, 0x7f2c3f720700) = 0
mprotect(0x7f2c3f3ef000, 16384, PROT_READ) = 0
mprotect(0x61c000, 4096, PROT_READ)     = 0
mprotect(0x7f2c3f625000, 4096, PROT_READ) = 0
munmap(0x7f2c3f745000, 20599)           = 0
brk(NULL)                               = 0x7f0000
brk(0x811000)                           = 0x811000
open("/usr/lib/locale/locale-archive", O_RDONLY|O_CLOEXEC) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=1668976, ...}) = 0
mmap(NULL, 1668976, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f2c3f48d000
close(3)                                = 0
newfstatat(AT_FDCWD, "test.bin", {st_mode=S_IFREG|0777, st_size=10485760, ...}, AT_SYMLINK_NOFOLLOW) = 0
fstat(1, {st_mode=S_IFCHR|0620, st_rdev=makedev(4, 3), ...}) = 0
ioctl(1, TCGETS, {B38400 opost isig icanon echo ...}) = 0
write(1, "5.1G\ttest.bin\n", 145.1G     test.bin
)        = 14
close(1)                                = 0
close(2)                                = 0
exit_group(0)                           = ?
+++ exited with 0 +++

[marcogroppo]

On DrvFs the stat system call returns a bogus number of blocks (maybe file size + 1?):

$ stat ~/test.bin
  File: '/home/marco/test.bin'
  Size: 10485760        Blocks: 20480      IO Block: 4096   regular file
Device: 10h/16d Inode: 17451448556193666  Links: 1
Access: (0644/-rw-r--r--)  Uid: ( 1000/   marco)   Gid: ( 1000/   marco)
...

$ stat /mnt/c/Users/Marco/test.bin
  File: '/mnt/c/Users/Marco/test.bin'
  Size: 10485760        Blocks: 10485761   IO Block: 4096   regular file
Device: eh/14d  Inode: 7318349394488527  Links: 1
Access: (0777/-rwxrwxrwx)  Uid: (    0/    root)   Gid: (    0/    root)

[jonmclean]

I have the same issue. Copied this to User Voice at https://wpdev.uservoice.com/forums/266908-command-prompt-console-bash-on-ubuntu-on-windo/suggestions/19809499-du-h-reports-wrong-file-size-on-drvfs. Please vote for it there.

[marcogroppo]

The bug fix should be on its way: #2211 (comment)

[benhillis]

Fixed in 16237.