Hmmm ok,
Well the reason I flagged it as a bug, is because the btrfsmaintenance
package uses a script to test to see if a filesystem is btrfs and
incorrectly uses stat -f to do it. This must have worked in the past
else they would not use it.
The code snippet is:
# function: is_btrfs
# parameter: path to a mounted filesystem
#
# check if filesystem is a btrfs
is_btrfs() {
local FS=$(stat -f --format=%T "$1")
[ "$FS" = "btrfs" ] && return 0
return 1
}
Obviously that is targeted at mounted filesystems, but the documentation
and usage always shows "<path>|<device>" as a parameter.
I guess I should file a bug against that package but I am curious as to
when the default behaviour changed.
Thanks for your response.
On 13/07/2023 10:59, Pádraig Brady wrote:
tag 64588 notabug
close 64588
stop
On 12/07/2023 23:46, support wrote:
coreutils version 9.1-1 on Debian testing, but also exists in previous
versions.
Example:
stat -f /dev/sdb
File: "/dev/sdb"
ID: eb91af7d7bda02dd Namelen: 255 Type: tmpfs
Block size: 4096 Fundamental block size: 4096
Blocks: Total: 2012292 Free: 2012292 Available: 2012292
Inodes: Total: 2012292 Free: 2011839
stat -f /dev/disk/by-uuid/6abaa68a-2670-4d8b-8d2a-fd7321df9242
File: "/dev/disk/by-uuid/6abaa68a-2670-4d8b-8d2a-fd7321df9242"
ID: eb91af7d7bda02dd Namelen: 255 Type: tmpfs
Block size: 4096 Fundamental block size: 4096
Blocks: Total: 2012292 Free: 2012292 Available: 2012292
Inodes: Total: 2012292 Free: 2011839
blkid /dev/sdb
/dev/sdb: UUID="6abaa68a-2670-4d8b-8d2a-fd7321df9242"
UUID_SUB="d15f1846-8f18-4ba0-9e2a-a6aaa7bbf83b" BLOCK_SIZE="4096"
TYPE="btrfs"
Not sure why the reported fstype is wrong but obviously it is a bug.
This is expected. From the info docs:
"stat does not search for specified device nodes in the file system list,
instead operating on them directly"
I.e. /dev/sdb is a device node in the /dev file system, which is tmpfs.
You can confirm this with:
strace -e statfs stat -f -c %T /dev/sdb
strace -e statfs df --output=fstype /dev/sdb
If you wanted to operate on a file system mounted on the device node
you could:
stat -f $(df --output=target /dev/sdb | tail -n1)
cheers,
Pádraig
