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, 24 insertions, 13 deletions

diff --git a/drivers/mtd/ubi/eba.c b/drivers/mtd/ubi/eba.c
index 2e4d6bf94582..048a606cebde 100644
--- a/drivers/mtd/ubi/eba.c
+++ b/drivers/mtd/ubi/eba.c
@@ -949,10 +949,14 @@ write_error:
  * This function copies logical eraseblock from physical eraseblock @from to
  * physical eraseblock @to. The @vid_hdr buffer may be changed by this
  * function. Returns:
- *   o %0  in case of success;
- *   o %1 if the operation was canceled and should be tried later (e.g.,
- *     because a bit-flip was detected at the target PEB);
- *   o %2 if the volume is being deleted and this LEB should not be moved.
+ *   o %0 in case of success;
+ *   o %1 if the operation was canceled because the volume is being deleted
+ *        or because the PEB was put meanwhile;
+ *   o %2 if the operation was canceled because there was a write error to the
+ *        target PEB;
+ *   o %-EAGAIN if the operation was canceled because a bit-flip was detected
+ *     in the target PEB;
+ *   o a negative error code in case of failure.
  */
 int ubi_eba_copy_leb(struct ubi_device *ubi, int from, int to,
                      struct ubi_vid_hdr *vid_hdr)
@@ -978,7 +982,7 @@ int ubi_eba_copy_leb(struct ubi_device *ubi, int from, int to,
         /*
          * Note, we may race with volume deletion, which means that the volume
          * this logical eraseblock belongs to might be being deleted. Since the
-         * volume deletion unmaps all the volume's logical eraseblocks, it will
+         * volume deletion un-maps all the volume's logical eraseblocks, it will
          * be locked in 'ubi_wl_put_peb()' and wait for the WL worker to finish.
          */
         vol = ubi->volumes[idx];
@@ -986,7 +990,7 @@ int ubi_eba_copy_leb(struct ubi_device *ubi, int from, int to,
                 /* No need to do further work, cancel */
                 dbg_eba("volume %d is being removed, cancel", vol_id);
                 spin_unlock(&ubi->volumes_lock);
-                return 2;
+                return 1;
         }
         spin_unlock(&ubi->volumes_lock);
 
@@ -1023,7 +1027,7 @@ int ubi_eba_copy_leb(struct ubi_device *ubi, int from, int to,
 
         /*
          * OK, now the LEB is locked and we can safely start moving it. Since
-         * this function utilizes thie @ubi->peb1_buf buffer which is shared
+         * this function utilizes the @ubi->peb1_buf buffer which is shared
          * with some other functions, so lock the buffer by taking the
          * @ubi->buf_mutex.
          */
@@ -1068,8 +1072,11 @@ int ubi_eba_copy_leb(struct ubi_device *ubi, int from, int to,
         vid_hdr->sqnum = cpu_to_be64(next_sqnum(ubi));
 
         err = ubi_io_write_vid_hdr(ubi, to, vid_hdr);
-        if (err)
+        if (err) {
+                if (err == -EIO)
+                        err = 2;
                 goto out_unlock_buf;
+        }
 
         cond_resched();
 
@@ -1079,14 +1086,17 @@ int ubi_eba_copy_leb(struct ubi_device *ubi, int from, int to,
                 if (err != UBI_IO_BITFLIPS)
                         ubi_warn("cannot read VID header back from PEB %d", to);
                 else
-                        err = 1;
+                        err = -EAGAIN;
                 goto out_unlock_buf;
         }
 
         if (data_size > 0) {
                 err = ubi_io_write_data(ubi, ubi->peb_buf1, to, 0, aldata_size);
-                if (err)
+                if (err) {
+                        if (err == -EIO)
+                                err = 2;
                         goto out_unlock_buf;
+                }
 
                 cond_resched();
 
@@ -1101,15 +1111,16 @@ int ubi_eba_copy_leb(struct ubi_device *ubi, int from, int to,
                                 ubi_warn("cannot read data back from PEB %d",
                                          to);
                         else
-                                err = 1;
+                                err = -EAGAIN;
                         goto out_unlock_buf;
                 }
 
                 cond_resched();
 
                 if (memcmp(ubi->peb_buf1, ubi->peb_buf2, aldata_size)) {
-                        ubi_warn("read data back from PEB %d - it is different",
-                                 to);
+                        ubi_warn("read data back from PEB %d and it is "
+                                 "different", to);
+                        err = -EINVAL;
                         goto out_unlock_buf;
                 }
         }