NFS: Add a cond_resched() to nfs_commit_release_pages()

commit 7f1bda447c9bd48b415acedba6b830f61591601f upstream.

The commit list can get very large, and so we need a cond_resched()
in nfs_commit_release_pages() in order to ensure we don't hog the CPU
for excessive periods of time.

Reported-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index de32580..76da415 100644 (file)
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -1836,6 +1836,8 @@ static void nfs_commit_release_pages(struct nfs_commit_data *data)
                set_bit(NFS_CONTEXT_RESEND_WRITES, &req->wb_context->flags);
        next:
                nfs_unlock_and_release_request(req);
+               /* Latency breaker */
+               cond_resched();
        }
        nfss = NFS_SERVER(data->inode);
        if (atomic_long_read(&nfss->writeback) < NFS_CONGESTION_OFF_THRESH)