Re: [PATCH 7/6] Lost bits - fix PG_writeback vs PG_private race in NFS

Peter Zijlstra
2006-08-25T16:36:53Z

Make sure we clear PG_writeback after we clear PG_private, otherwise
weird and wonderfull stuff will happen.

Also, teach try_to_release_page() about PG_swapcache pages.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
---
fs/buffer.c | 2 +-
fs/nfs/write.c | 5 ++---
2 files changed, 3 insertions(+), 4 deletions(-)

Index: linux-2.6/fs/buffer.c
===================================================================
--- linux-2.6.orig/fs/buffer.c
+++ linux-2.6/fs/buffer.c
@@ -1567,7 +1567,7 @@ static void discard_buffer(struct buffer
*/
int try_to_release_page(struct page *page, gfp_t gfp_mask)
{
- struct address_space * const mapping = page->mapping;
+ struct address_space * const mapping = page_mapping(page);

BUG_ON(!PageLocked(page));
if (PageWriteback(page))
Index: linux-2.6/fs/nfs/write.c
===================================================================
--- linux-2.6.orig/fs/nfs/write.c
+++ linux-2.6/fs/nfs/write.c
@@ -902,7 +902,6 @@ done:

static void nfs_writepage_release(struct nfs_page *req)
{
- end_page_writeback(req->wb_page);

#if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
if (!PageError(req->wb_page)) {
@@ -922,6 +921,7 @@ out:
#else
nfs_inode_remove_request(req);
#endif
+ end_page_writeback(req->wb_page);
nfs_clear_page_writeback(req);
}

@@ -1222,12 +1222,10 @@ static void nfs_writeback_done_full(stru
ClearPageUptodate(page);
SetPageError(page);
req->wb_context->error = task->tk_status;
- end_page_writeback(page);
nfs_inode_remove_request(req);
dprintk(", error = %d\n", task->tk_status);
goto next;
}
- end_page_writeback(page);

#if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
if (data->args.stable != NFS_UNSTABLE || data->verf.committed == NFS_FILE_SYNC) {
@@ -1242,6 +1240,7 @@ static void nfs_writeback_done_full(stru
nfs_inode_remove_request(req);
#endif
next:
+ end_page_writeback(page);
nfs_clear_page_writeback(req);
}
}