When simple quotas is enabled, every new data extent gets a special
inline OWNER_REF item that identifies the owning subvolume. This makes
simple quotas backwards incompatible with kernels older than v6.7. Even
if you disable quotas on the filesystem, the OWNER_REF items are
sprinkled throughout the extent tree and older kernels are unable to
parse them.
However, it is relatively easy to simply walk the extent tree and remove
these inline ref items. This gives squota adopters the option to *fully*
disable squotas on their system and un-set the incompat bit. Add this
capability to btrfstune, which requires only a little tricky btrfs item
data shifting.
This functionality was tested with a new unit test, as well as a similar
but more thorough integration test in fstests
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Boris Burkov <boris@bur.io>
This simply zero's out the path, and this is used everywhere we use a
stack path. Drop this usage and simply init the path's to empty instead
of using a function to do the memset.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Add the ability to enable simple quotas on an existing file system at
rest with btrfstune.
This is similar to the functionality in mkfs, except it must also find
all the roots for which it must create qgroups. Note that this *does
not* retroactively compute usage for existing extents as that is
impossible for data. This is consistent with the behavior of the live
enable ioctl.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Boris Burkov <boris@bur.io>
Signed-off-by: David Sterba <dsterba@suse.com>
