From: Tim Chase <tim@chase2k.com>
Date: Thu, 3 Sep 2015 12:13:15 +0000 (-0500)
Subject: Prevent reclaim in the traverse prefetch thread
X-Git-Tag: zfs-0.6.5~9
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=dca8c34da4212ed85a92111f26bd3a3cd782f270;p=zfs

Prevent reclaim in the traverse prefetch thread

Reclaim in the traverse prefetch thread, which is run on the system
taskq, can overrun the stack.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tim Chase <tim@chase2k.com>
Closes #3733
---

diff --git a/module/zfs/dmu_traverse.c b/module/zfs/dmu_traverse.c
index 44b23280d..12d099bfd 100644
--- a/module/zfs/dmu_traverse.c
+++ b/module/zfs/dmu_traverse.c
@@ -476,6 +476,7 @@ traverse_prefetch_thread(void *arg)
 	traverse_data_t *td_main = arg;
 	traverse_data_t td = *td_main;
 	zbookmark_phys_t czb;
+	fstrans_cookie_t cookie = spl_fstrans_mark();
 
 	td.td_func = traverse_prefetcher;
 	td.td_arg = td_main->td_pfd;
@@ -489,6 +490,7 @@ traverse_prefetch_thread(void *arg)
 	td_main->td_pfd->pd_exited = B_TRUE;
 	cv_broadcast(&td_main->td_pfd->pd_cv);
 	mutex_exit(&td_main->td_pfd->pd_mtx);
+	spl_fstrans_unmark(cookie);
 }
 
 /*