Christoph Hellwig writes:
> On Thu, Oct 31, 2002 at 07:45:39PM +0300, Nikita Danilov wrote:
> > Interesting. Then, XFS and JFS meta data in the page cache probably
> > are linearly ordered, and there it is never necessary to remove meta
> > data page from the middle of the mapping, right?
>
> The issue is rather different for XFS and JFS. in JFS most metadata
> (actually all metadata but the small superblock) is stored in inodes,
> and it's accessed through the pagecache mapping for those inodes.
>
> All access to those pages doesn't go directly through the pagecache
> interface but a small metapage wrapper. When the page is removed it's synced
> to disk and removed from the metapage hash, so that you can't acess it
> anymore. It might still be on the VM lists for a while.
Interesting. But things like ->vm_writeback() and friends will go
directly to the page bypassing metapage wrapper, right? JFS checks that
page is still "live" on each low-level VM call?
>
> XFS on the other hand only uses the blockdevice mapping to acess it's
> metadata so it doesn't have to remove the page explicitly from the
> cache ever.
>
Nikita.
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This archive was generated by hypermail 2b29 : Thu Oct 31 2002 - 22:00:54 EST