NFS: Fix a write request leak in nfs_invalidate_page()
Ryusuke Konishi says:
The recent truncate_complete_page() clears the dirty flag from a page
before calling a_ops->invalidatepage(),
^^^^^^
static void
truncate_complete_page(struct address_space *mapping, struct page *page)
{
...
cancel_dirty_page(page, PAGE_CACHE_SIZE); <--- Inserted here at
kernel 2.6.20
if (PagePrivate(page))
do_invalidatepage(page, 0); ---> will call
a_ops->invalidatepage()
...
}
and this is disturbing nfs_wb_page_priority() from calling
nfs_writepage_locked() that is expected to handle the pending
request (=nfs_page) associated with the page.
int nfs_wb_page_priority(struct inode *inode, struct page *page, int how)
{
...
if (clear_page_dirty_for_io(page)) {
ret = nfs_writepage_locked(page, &wbc);
if (ret < 0)
goto out;
}
...
}
Since truncate_complete_page() will get rid of the page after
a_ops->invalidatepage() returns, the request (=nfs_page) associated
with the page becomes a garbage in nfs_inode->nfs_page_tree.
------------------------
Fix this by ensuring that nfs_wb_page_priority() recognises that it may
also need to clear out non-dirty pages that have an nfs_page associated
with them.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index ef97e0c..0d7a77c 100644
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -1396,6 +1396,50 @@
return ret;
}
+int nfs_wb_page_cancel(struct inode *inode, struct page *page)
+{
+ struct nfs_page *req;
+ loff_t range_start = page_offset(page);
+ loff_t range_end = range_start + (loff_t)(PAGE_CACHE_SIZE - 1);
+ struct writeback_control wbc = {
+ .bdi = page->mapping->backing_dev_info,
+ .sync_mode = WB_SYNC_ALL,
+ .nr_to_write = LONG_MAX,
+ .range_start = range_start,
+ .range_end = range_end,
+ };
+ int ret = 0;
+
+ BUG_ON(!PageLocked(page));
+ for (;;) {
+ req = nfs_page_find_request(page);
+ if (req == NULL)
+ goto out;
+ if (test_bit(PG_NEED_COMMIT, &req->wb_flags)) {
+ nfs_release_request(req);
+ break;
+ }
+ if (nfs_lock_request_dontget(req)) {
+ nfs_inode_remove_request(req);
+ /*
+ * In case nfs_inode_remove_request has marked the
+ * page as being dirty
+ */
+ cancel_dirty_page(page, PAGE_CACHE_SIZE);
+ nfs_unlock_request(req);
+ break;
+ }
+ ret = nfs_wait_on_request(req);
+ if (ret < 0)
+ goto out;
+ }
+ if (!PagePrivate(page))
+ return 0;
+ ret = nfs_sync_mapping_wait(page->mapping, &wbc, FLUSH_INVALIDATE);
+out:
+ return ret;
+}
+
int nfs_wb_page_priority(struct inode *inode, struct page *page, int how)
{
loff_t range_start = page_offset(page);
