Commit cd52ed35 authored by Trond Myklebust's avatar Trond Myklebust
Browse files

NFS: Avoid races between writebacks and truncation

Currently, there is no serialisation between NFS asynchronous writebacks
and truncation at the page level due to the fact that nfs_sync_inode()
cannot lock the pages that it is about to write out.

This means that it is possible to be flushing out data (and calling something
like set_page_writeback()) while the page cache is busy evicting the page.

Use the hooks provided in try_to_release_page() to ensure that dirty pages
are always written back to storage before we evict them.
Signed-off-by: default avatarTrond Myklebust <>
parent b92dccf6
......@@ -316,6 +316,17 @@ static int nfs_commit_write(struct file *file, struct page *page, unsigned offse
return status;
static int nfs_invalidate_page(struct page *page, unsigned long offset)
/* FIXME: we really should cancel any unstarted writes on this page */
return 1;
static int nfs_release_page(struct page *page, gfp_t gfp)
return !nfs_wb_page(page->mapping->host, page);
struct address_space_operations nfs_file_aops = {
.readpage = nfs_readpage,
.readpages = nfs_readpages,
......@@ -324,6 +335,8 @@ struct address_space_operations nfs_file_aops = {
.writepages = nfs_writepages,
.prepare_write = nfs_prepare_write,
.commit_write = nfs_commit_write,
.invalidatepage = nfs_invalidate_page,
.releasepage = nfs_release_page,
.direct_IO = nfs_direct_IO,
......@@ -85,6 +85,10 @@ nfs_create_request(struct nfs_open_context *ctx, struct inode *inode,
atomic_set(&req->wb_complete, 0);
req->wb_index = page->index;
BUG_ON(page->mapping->host != inode);
req->wb_offset = offset;
req->wb_pgbase = offset;
req->wb_bytes = count;
......@@ -147,8 +151,10 @@ void nfs_clear_page_writeback(struct nfs_page *req)
void nfs_clear_request(struct nfs_page *req)
if (req->wb_page) {
struct page *page = req->wb_page;
if (page != NULL) {
req->wb_page = NULL;
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