NFS: Ensure that nfs_wb_page() waits for Pg_writeback to clear
Neil Brown reports that he is seeing the BUG_ON(ret == 0) trigger in
nfs_page_async_flush. According to the trace in
https://bugzilla.novell.com/show_bug.cgi?id=599628
the problem appears to be due to nfs_wb_page() not waiting for the
PG_writeback flag to clear.
There is a ditto problem in nfs_wb_page_cancel()
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index ccde2ae..3aea3ca 100644
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -1472,6 +1472,7 @@
BUG_ON(!PageLocked(page));
for (;;) {
+ wait_on_page_writeback(page);
req = nfs_page_find_request(page);
if (req == NULL)
break;
@@ -1506,30 +1507,18 @@
.range_start = range_start,
.range_end = range_end,
};
- struct nfs_page *req;
- int need_commit;
int ret;
while(PagePrivate(page)) {
+ wait_on_page_writeback(page);
if (clear_page_dirty_for_io(page)) {
ret = nfs_writepage_locked(page, &wbc);
if (ret < 0)
goto out_error;
}
- req = nfs_find_and_lock_request(page);
- if (!req)
- break;
- if (IS_ERR(req)) {
- ret = PTR_ERR(req);
+ ret = sync_inode(inode, &wbc);
+ if (ret < 0)
goto out_error;
- }
- need_commit = test_bit(PG_CLEAN, &req->wb_flags);
- nfs_clear_page_tag_locked(req);
- if (need_commit) {
- ret = nfs_commit_inode(inode, FLUSH_SYNC);
- if (ret < 0)
- goto out_error;
- }
}
return 0;
out_error: