6.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
commit be2fd1560eb57b7298aa3c258ddcca0d53ecdea3 upstream.
Be more careful when tearing down the subrequests of an O_DIRECT write
as part of a retransmission.
Reported-by: Chris Mason <clm@xxxxxx>
Fixes: ed5d588fe47f ("NFS: Try to join page groups before an O_DIRECT retransmission")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/nfs/direct.c | 26 ++++++++++++++++----------
1 file changed, 16 insertions(+), 10 deletions(-)
--- a/fs/nfs/direct.c
+++ b/fs/nfs/direct.c
@@ -472,20 +472,26 @@ out:
return result;
}
-static void
-nfs_direct_join_group(struct list_head *list, struct inode *inode)
+static void nfs_direct_join_group(struct list_head *list, struct inode *inode)
{
- struct nfs_page *req, *next;
+ struct nfs_page *req, *subreq;
list_for_each_entry(req, list, wb_list) {
- if (req->wb_head != req || req->wb_this_page == req)
+ if (req->wb_head != req)
continue;
- for (next = req->wb_this_page;
- next != req->wb_head;
- next = next->wb_this_page) {
- nfs_list_remove_request(next);
- nfs_release_request(next);
- }
+ subreq = req->wb_this_page;
+ if (subreq == req)
+ continue;
+ do {
+ /*
+ * Remove subrequests from this list before freeing
+ * them in the call to nfs_join_page_group().
+ */
+ if (!list_empty(&subreq->wb_list)) {
+ nfs_list_remove_request(subreq);
+ nfs_release_request(subreq);
+ }
+ } while ((subreq = subreq->wb_this_page) != req);
nfs_join_page_group(req, inode);
}
}
