On 2022/9/5 22:53, David Sterba wrote:
On Tue, Aug 09, 2022 at 01:02:16PM +0800, Qu Wenruo wrote:
Currently there are two corner cases not handling compat RO flags
correctly:
- Remount
We can still mount the fs RO with compat RO flags, then remount it RW.
We should not allow any write into a fs with unsupported RO flags.
- Still try to search block group items
In fact, behavior/on-disk format change to extent tree should not
need a full incompat flag.
And since we can ensure fs with unsupported RO flags never got any
writes (with above case fixed), then we can even skip block group
items search at mount time.
This patch will enhance the unsupported RO compat flags by:
- Reject RW remount if there is unsupported RO compat flags
- Go dummy block group items directly for unsupported RO compat flags
In fact, only changes to chunk/subvolume/root/csum trees should go
incompat flags.
The latter part should allow future change to extent tree to be compat
RO flags.
Thus this patch also needs to be backported to all stable trees.
Cc: stable@xxxxxxxxxxxxxxx
This applies cleanly only to 5.19, anything else would need a separate
backport. I'm planning to send this patch among 6.0 fixes so this
should give us time to get it to older stable kernels before the block
group tree is released.
No problem, in fact I (normally) only start backports when I got the
failed to apply message from Greg.
So I'd go the regular backport cycle for it.
Thanks,
Qu
