From 297e908f08cb40c4bbe11b06c30ff1de1a3740c0 Mon Sep 17 00:00:00 2001 From: Jinshan Xiong Date: Tue, 16 Aug 2016 16:18:58 -0400 Subject: [PATCH] staging: lustre: llite: Fix the deadlock in balance_dirty_pages() If the page is already dirtied in ll_write_end() and kernel tries to call balance_dirty_pages() to write back dirty pages in the same thread, this is deadlock case if the page is already held by clio. This can also fix the issue of LU-4873. Signed-off-by: Jinshan Xiong Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-4977 Reviewed-on: http://review.whamcloud.com/10149 Reviewed-by: Bobi Jam Reviewed-by: Lai Siyao Reviewed-by: Oleg Drokin Signed-off-by: James Simmons Signed-off-by: Greg Kroah-Hartman --- drivers/staging/lustre/lustre/llite/rw26.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/drivers/staging/lustre/lustre/llite/rw26.c b/drivers/staging/lustre/lustre/llite/rw26.c index c14a1b680505..8c8c10044826 100644 --- a/drivers/staging/lustre/lustre/llite/rw26.c +++ b/drivers/staging/lustre/lustre/llite/rw26.c @@ -506,9 +506,8 @@ static int ll_write_begin(struct file *file, struct address_space *mapping, env = lcc->lcc_env; io = lcc->lcc_io; - if (likely(to == PAGE_SIZE)) /* LU-4873 */ - /* To avoid deadlock, try to lock page first. */ - vmpage = grab_cache_page_nowait(mapping, index); + /* To avoid deadlock, try to lock page first. */ + vmpage = grab_cache_page_nowait(mapping, index); if (unlikely(!vmpage || PageDirty(vmpage) || PageWriteback(vmpage))) { struct vvp_io *vio = vvp_env_io(env); struct cl_page_list *plist = &vio->u.write.vui_queue; @@ -617,6 +616,13 @@ static int ll_write_end(struct file *file, struct address_space *mapping, LASSERT(from == 0); vio->u.write.vui_to = from + copied; + /* + * To address the deadlock in balance_dirty_pages() where + * this dirty page may be written back in the same thread. + */ + if (PageDirty(vmpage)) + unplug = true; + /* We may have one full RPC, commit it soon */ if (plist->pl_nr >= PTLRPC_MAX_BRW_PAGES) unplug = true; -- 2.20.1