UBI: handle write errors in WL worker

When a PEB is moved and a write error happens, UBI switches
to R/O mode, which is wrong, because we just copy the data
and may select a different PEB and re-try this. This patch
fixes WL worker's behavior.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

1 files changed, 20 insertions, 12 deletions

diff --git a/drivers/mtd/ubi/wl.c b/drivers/mtd/ubi/wl.c
index 442099d76ec9..abf65ea414e7 100644
--- a/drivers/mtd/ubi/wl.c
+++ b/drivers/mtd/ubi/wl.c
@@ -738,7 +738,7 @@ static int schedule_erase(struct ubi_device *ubi, struct ubi_wl_entry *e,
 static int wear_leveling_worker(struct ubi_device *ubi, struct ubi_work *wrk,
                                 int cancel)
 {
-        int err, scrubbing = 0;
+        int err, scrubbing = 0, torture = 0;
         struct ubi_wl_prot_entry *uninitialized_var(pe);
         struct ubi_wl_entry *e1, *e2;
         struct ubi_vid_hdr *vid_hdr;
@@ -842,20 +842,26 @@ static int wear_leveling_worker(struct ubi_device *ubi, struct ubi_work *wrk,
 
         err = ubi_eba_copy_leb(ubi, e1->pnum, e2->pnum, vid_hdr);
         if (err) {
-
+                if (err == -EAGAIN)
+                        goto out_not_moved;
                 if (err < 0)
                         goto out_error;
-                if (err == 1)
+                if (err == 2) {
+                        /* Target PEB write error, torture it */
+                        torture = 1;
                         goto out_not_moved;
+                }
 
                 /*
-                 * For some reason the LEB was not moved - it might be because
-                 * the volume is being deleted. We should prevent this PEB from
-                 * being selected for wear-levelling movement for some "time",
-                 * so put it to the protection tree.
+                 * The LEB has not been moved because the volume is being
+                 * deleted or the PEB has been put meanwhile. We should prevent
+                 * this PEB from being selected for wear-leveling movement
+                 * again, so put it to the protection tree.
                  */
 
-                dbg_wl("cancelled moving PEB %d", e1->pnum);
+                dbg_wl("canceled moving PEB %d", e1->pnum);
+                ubi_assert(err == 1);
+
                 pe = kmalloc(sizeof(struct ubi_wl_prot_entry), GFP_NOFS);
                 if (!pe) {
                         err = -ENOMEM;
@@ -920,9 +926,10 @@ static int wear_leveling_worker(struct ubi_device *ubi, struct ubi_work *wrk,
         /*
          * For some reasons the LEB was not moved, might be an error, might be
          * something else. @e1 was not changed, so return it back. @e2 might
-         * be changed, schedule it for erasure.
+         * have been changed, schedule it for erasure.
          */
 out_not_moved:
+        dbg_wl("canceled moving PEB %d", e1->pnum);
         ubi_free_vid_hdr(ubi, vid_hdr);
         vid_hdr = NULL;
         spin_lock(&ubi->wl_lock);
@@ -930,12 +937,13 @@ out_not_moved:
                 wl_tree_add(e1, &ubi->scrub);
         else
                 wl_tree_add(e1, &ubi->used);
+        ubi_assert(!ubi->move_to_put);
         ubi->move_from = ubi->move_to = NULL;
-        ubi->move_to_put = ubi->wl_scheduled = 0;
+        ubi->wl_scheduled = 0;
         spin_unlock(&ubi->wl_lock);
 
         e1 = NULL;
-        err = schedule_erase(ubi, e2, 0);
+        err = schedule_erase(ubi, e2, torture);
         if (err)
                 goto out_error;
 
@@ -1324,7 +1332,7 @@ int ubi_wl_flush(struct ubi_device *ubi)
         up_write(&ubi->work_sem);
 
         /*
-         * And in case last was the WL worker and it cancelled the LEB
+         * And in case last was the WL worker and it canceled the LEB
          * movement, flush again.
          */
         while (ubi->works_count) {