Re: Why a lot of fses are using bdev's page cache to do super block read/write?

Matthew Wilcox
2025-07-09T12:01:27Z

On Wed, Jul 09, 2025 at 06:35:00PM +0930, Qu Wenruo wrote:
> This leads more digging, and to my surprise using bdev's page cache to do
> superblock IOs is not an exception, in fact f2fs is doing exactly the same
> thing.

Almost all filesystems use the page cache (sometimes the buffer cache
which amounts to the exact same thing). This is a good thing as many
filesystems put their superblock in the same place, so scanning block
devices to determine what filesystem they have results in less I/O.