On Wed, Oct 11 2023 at  4:20P -0400,
Jens Axboe [off-list ref] wrote:

On 10/11/23 2:12 PM, Sarthak Kukreti wrote:

quoted

Only call truncate_bdev_range() if the fallocate mode is
supported. This fixes a bug where data in the pagecache
could be invalidated if the fallocate() was called on the
block device with an invalid mode.

Fix looks fine, but would be nicer if we didn't have to duplicate the
truncate_bdev_range() in each switch clause. Can we check this upfront
instead?

No, if you look at the function (rather than just the patch in
isolation) we need to make the call for each case rather than collapse
to a single call at the front (that's the reason for this fix, because
otherwise the default: error case will invalidate the page cache too).

Just so you're aware, I also had this feedback that shaped the patch a
bit back in April:
https://listman.redhat.com/archives/dm-devel/2023-April/053986.html

Also, please wrap commit messages at 72-74 chars.

Not seeing where the header should be wrapped.  You referring to the
Fixes: line?  I've never seen those wrapped.

Mike