Messages in this thread | | | From | Nikita Danilov <> | Date | Thu, 31 Oct 2002 20:04:40 +0300 | Subject | Re: [PATCH]: reiser4 [5/8] export remove_from_page_cache() |
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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. >
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