This is a note to let you know that I've just added the patch titled
pnfs-obj: Fix __r4w_get_page when offset is beyond i_size
to the 3.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
pnfs-obj-fix-__r4w_get_page-when-offset-is-beyond-i_size.patch
and it can be found in the queue-3.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
From: Boaz Harrosh <[email protected]>
Date: Fri, 8 Jun 2012 02:02:30 +0300
Subject: pnfs-obj: Fix __r4w_get_page when offset is beyond i_size
From: Boaz Harrosh <[email protected]>
commit c999ff68029ebd0f56ccae75444f640f6d5a27d2 upstream.
It is very common for the end of the file to be unaligned on
stripe size. But since we know it's beyond file's end then
the XOR should be preformed with all zeros.
Old code used to just read zeros out of the OSD devices, which is a great
waist. But what scares me more about this situation is that, we now have
pages attached to the file's mapping that are beyond i_size. I don't
like the kind of bugs this calls for.
Fix both birds, by returning a global zero_page, if offset is beyond
i_size.
TODO:
Change the API to ->__r4w_get_page() so a NULL can be
returned without being considered as error, since XOR API
treats NULL entries as zero_pages.
[Bug since 3.2. Should apply the same way to all Kernels since]
Signed-off-by: Boaz Harrosh <[email protected]>
[bwh: Backported to 3.2: adjust for lack of wdata->header]
Signed-off-by: Ben Hutchings <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
fs/nfs/objlayout/objio_osd.c | 16 +++++++++++++---
1 file changed, 13 insertions(+), 3 deletions(-)
--- a/fs/nfs/objlayout/objio_osd.c
+++ b/fs/nfs/objlayout/objio_osd.c
@@ -487,8 +487,16 @@ static struct page *__r4w_get_page(void
struct objio_state *objios = priv;
struct nfs_write_data *wdata = objios->oir.rpcdata;
pgoff_t index = offset / PAGE_SIZE;
- struct page *page = find_get_page(wdata->inode->i_mapping, index);
+ struct page *page;
+ loff_t i_size = i_size_read(wdata->inode);
+ if (offset >= i_size) {
+ *uptodate = true;
+ dprintk("%s: g_zero_page index=0x%lx\n", __func__, index);
+ return ZERO_PAGE(0);
+ }
+
+ page = find_get_page(wdata->inode->i_mapping, index);
if (!page) {
page = find_or_create_page(wdata->inode->i_mapping,
index, GFP_NOFS);
@@ -509,8 +517,10 @@ static struct page *__r4w_get_page(void
static void __r4w_put_page(void *priv, struct page *page)
{
- dprintk("%s: index=0x%lx\n", __func__, page->index);
- page_cache_release(page);
+ dprintk("%s: index=0x%lx\n", __func__,
+ (page == ZERO_PAGE(0)) ? -1UL : page->index);
+ if (ZERO_PAGE(0) != page)
+ page_cache_release(page);
return;
}
Patches currently in stable-queue which might be from [email protected] are
queue-3.4/pnfs-obj-fix-__r4w_get_page-when-offset-is-beyond-i_size.patch
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