[lustre-devel] [PATCH 39/49] lustre: lov: fault page update cp_lov_index

[James Simmons <jsimmons@infradead.org>]

From: Bobi Jam <bobijam@whamcloud.com>

In fault IO, vvp_io_fault_start() could find an existing cl_page
associated with the vmpage covering the fault index, and the page
may still refer to another mirror of an old IO.

This patch update the fault page's cp_lov_index in lov_io_fault_start

WC-bug-id: https://jira.whamcloud.com/browse/LU-14502
Lustre-commit: e9bac5fa455eab5 ("LU-14502 lov: fault page update cp_lov_index")
Signed-off-by: Bobi Jam <bobijam@whamcloud.com>
Reviewed-on: https://review.whamcloud.com/41954
Reviewed-by: Wang Shilong <wshilong@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>
Signed-off-by: James Simmons <jsimmons@infradead.org>
---
 fs/lustre/lov/lov_io.c | 37 +++++++++++++++++++++++++++++++++++++
 1 file changed, 37 insertions(+)

diff --git a/fs/lustre/lov/lov_io.c b/fs/lustre/lov/lov_io.c
index a8bba1c..9f67d16 100644
--- a/fs/lustre/lov/lov_io.c
+++ b/fs/lustre/lov/lov_io.c
@@ -1341,9 +1341,46 @@ static int lov_io_fault_start(const struct lu_env *env,
 	struct cl_fault_io *fio;
 	struct lov_io *lio;
 	struct lov_io_sub *sub;
+	loff_t offset;
+	int entry;
+	int stripe;
 
 	fio = &ios->cis_io->u.ci_fault;
 	lio = cl2lov_io(env, ios);
+
+	/**
+	 * LU-14502: ft_page could be an existing cl_page associated with
+	 * the vmpage covering the fault index, and the page may still
+	 * refer to another mirror of an old IO.
+	 */
+	if (lov_is_flr(lio->lis_object)) {
+		offset = cl_offset(ios->cis_obj, fio->ft_index);
+		entry = lov_io_layout_at(lio, offset);
+		if (entry < 0) {
+			CERROR(DFID": page fault index %lu invalid component: %d, mirror: %d\n",
+			       PFID(lu_object_fid(&ios->cis_obj->co_lu)),
+			       fio->ft_index, entry,
+			       lio->lis_mirror_index);
+			return -EIO;
+		}
+		stripe = lov_stripe_number(lio->lis_object->lo_lsm,
+					   entry, offset);
+
+		if (fio->ft_page->cp_lov_index !=
+		    lov_comp_index(entry, stripe)) {
+			CDEBUG(D_INFO,
+			       DFID": page fault at index %lu, at mirror %u comp entry %u stripe %u, been used with comp entry %u stripe %u\n",
+			       PFID(lu_object_fid(&ios->cis_obj->co_lu)),
+			       fio->ft_index, lio->lis_mirror_index,
+			       entry, stripe,
+			       lov_comp_entry(fio->ft_page->cp_lov_index),
+			       lov_comp_stripe(fio->ft_page->cp_lov_index));
+
+			fio->ft_page->cp_lov_index =
+					lov_comp_index(entry, stripe);
+		}
+	}
+
 	sub = lov_sub_get(env, lio, fio->ft_page->cp_lov_index);
 	if (IS_ERR(sub))
 		return PTR_ERR(sub);
-- 
1.8.3.1

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