On Tue, Jul 24, 2012 at 6:39 PM, Marios Titas <redneb8...@gmail.com> wrote:
> When I create a btrfs volume of size strictly less than 256 MiB then if I do
>     mount /dev/sdb1 /mnt/test
> the kernel tries unsuccessfully to do the mount with many other file systems
> before successfully trying with btrfs. For volumes of size larger than
> or equal to
> 256 MiB it just mounts the volume without doing that. Why is this discrepancy?

If I understand correctly, the kernel does not implement any fs
detection; this is performed by the mount utility, which indeed may
try a bunch of different filesystems until it finds one that works.

>From man mount:
              If no -t option is given, or if  the  auto  type  is  specified,
              mount  will try to guess the desired type.  Mount uses the blkid
              or volume_id library for guessing the filesystem type;  if  that
              does not turn up anything that looks familiar, mount will try to
              read the file /etc/filesystems, or,  if  that  does  not  exist,
              /proc/filesystems.   All  of  the  filesystem types listed there
              will be tried, except for those that are labeled "nodev"  (e.g.,
              devpts,  proc and nfs).  If /etc/filesystems ends in a line with
              a single * only, mount will read /proc/filesystems afterwards.
--
To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Reply via email to