Anand Jain wrote on 2015/11/25 20:08 +0800:
Sometimes users may want to have a btrfs to be supported on multiple
kernel version. A simple example, USB drive can be used with multiple
system running different kernel versions. Or in a data center a SAN
LUN could be mounted on any system with different kernel version.
Thanks for providing comments and feedback.
Further to it, here below is a set of patch which will introduce, to
specify a kernel version so that default features can be set based on
what features were supported at that kernel version.
With the new -O comp= option, the concern on user who want to make a
btrfs for newer kernel is hugely reduced.
But I still prefer such feature align to be done only when specified by
user, instead of automatically. (yeah, already told for several times
though)
Warning should be enough for user, sometimes too automatic is not good,
especially for tests.
A lot of btrfs-progs change, like recent disabling mixed-bg for small
volume has already cause regression in generic/077 testcase.
And Dave is already fed up with such problem from btrfs...
Especially such auto-detection will make default behavior more unstable,
at least not a good idea for me.
Beside this, I'm curious how other filesystm user tools handle such
kernel mismatch, or do they?
Thanks,
Qu
First of all to let user know what features was supported at what kernel
version. Patch 1/7 updates -O list-all which will list the feature with
version.
As we didn't maintain the sysfs and progs feature names consistent, so
to avoid confusion Patch 2/7 displays sysfs feature name as well again
in the list-all output.
Next, Patch 3,4,5/7 are helper functions.
Patch 6,7/7 provides the -O comp=<version> for mkfs.btrfs and
btrfs-convert respectively
Thanks, Anand
Anand Jain (7):
btrfs-progs: show the version for -O list-all
btrfs-progs: add kernel alias for each of the features in the list
btrfs-progs: make is_numerical non static
btrfs-progs: check for numerical in version_to_code()
btrfs-progs: introduce framework version to features
btrfs-progs: add -O comp= option for mkfs.btrfs
btrfs-progs: add -O comp= option for btrfs-convert
btrfs-convert.c | 21 +++++++++++++++++++++
cmds-replace.c | 11 -----------
mkfs.c | 24 ++++++++++++++++++++++--
utils.c | 58 ++++++++++++++++++++++++++++++++++++++++++++++++++++-----
utils.h | 2 ++
5 files changed, 98 insertions(+), 18 deletions(-)
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