Messages in this thread |  | | Date | Tue, 5 Nov 2013 12:30:05 -0500 | Subject | Re: [PATCH] ceph: Update the pages in fscache in writepages() path | From | Milosz Tanski <> |
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Li,
First, sorry for the late reply on this.
Currently fscache is only supported for files that are open in read only mode. I originally was going to let fscache cache in the write path as well as long as the file was open in with O_LAZY. I abandoned that idea. When a user opens the file in O_LAZY we can cache things locally with the assumption that the user will care of the synchronization in some other manner. There is no way of invalidating a subset of the pages in object cached by fscache, there is no way we can make O_LAZY work well.
The ceph_readpage_to_fscache() in writepage has no effect and it should be removed. ceph_readpage_to_fscache() calls cache_valid() to see if it should perform the page save, and since the file can't have a CACHE cap at the point in time it doesn't do it.
Thanks, - Milosz
On Thu, Oct 31, 2013 at 11:56 PM, Li Wang <liwang@ubuntukylin.com> wrote: > Currently, the pages in fscache only are updated in writepage() path, > add the process in writepages(). > > Signed-off-by: Min Chen <minchen@ubuntukylin.com> > Signed-off-by: Li Wang <liwang@ubuntukylin.com> > Signed-off-by: Yunchuan Wen <yunchuanwen@ubuntukylin.com> > --- > fs/ceph/addr.c | 8 +++++--- > 1 file changed, 5 insertions(+), 3 deletions(-) > > diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c > index 6df8bd4..cc57911 100644 > --- a/fs/ceph/addr.c > +++ b/fs/ceph/addr.c > @@ -746,7 +746,7 @@ retry: > > while (!done && index <= end) { > int num_ops = do_sync ? 2 : 1; > - unsigned i; > + unsigned i, j; > int first; > pgoff_t next; > int pvec_pages, locked_pages; > @@ -894,7 +894,6 @@ get_more_pages: > if (!locked_pages) > goto release_pvec_pages; > if (i) { > - int j; > BUG_ON(!locked_pages || first < 0); > > if (pvec_pages && i == pvec_pages && > @@ -924,7 +923,10 @@ get_more_pages: > > osd_req_op_extent_osd_data_pages(req, 0, pages, len, 0, > !!pool, false); > - > + for(j = 0; j < locked_pages; j++) { > + struct page *page = pages[j]; > + ceph_readpage_to_fscache(inode, page); > + } > pages = NULL; /* request message now owns the pages array */ > pool = NULL; > > -- > 1.7.9.5 > > -- > To unsubscribe from this list: send the line "unsubscribe ceph-devel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html
-- Milosz Tanski CTO 10 East 53rd Street, 37th floor New York, NY 10022
p: 646-253-9055 e: milosz@adfin.com
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