1 files changed, 33 insertions, 24 deletions

diff --git a/fs/ubifs/recovery.c b/fs/ubifs/recovery.c
index 805605250f12..e5f6cf8a1155 100644
--- a/fs/ubifs/recovery.c
+++ b/fs/ubifs/recovery.c
@@ -53,6 +53,25 @@ static int is_empty(void *buf, int len)
 }
 
 /**
+ * first_non_ff - find offset of the first non-0xff byte.
+ * @buf: buffer to search in
+ * @len: length of buffer
+ *
+ * This function returns offset of the first non-0xff byte in @buf or %-1 if
+ * the buffer contains only 0xff bytes.
+ */
+static int first_non_ff(void *buf, int len)
+{
+        uint8_t *p = buf;
+        int i;
+
+        for (i = 0; i < len; i++)
+                if (*p++ != 0xff)
+                        return i;
+        return -1;
+}
+
+/**
  * get_master_node - get the last valid master node allowing for corruption.
  * @c: UBIFS file-system description object
  * @lnum: LEB number
@@ -357,11 +376,7 @@ static int is_last_write(const struct ubifs_info *c, void *buf, int offs)
         empty_offs = ALIGN(offs + 1, c->min_io_size);
         check_len = c->leb_size - empty_offs;
         p = buf + empty_offs - offs;
-
-        for (; check_len > 0; check_len--)
-                if (*p++ != 0xff)
-                        return 0;
-        return 1;
+        return is_empty(p, check_len);
 }
 
 /**
@@ -543,8 +558,8 @@ static int drop_incomplete_group(struct ubifs_scan_leb *sleb, int *offs)
  *
  * This function does a scan of a LEB, but caters for errors that might have
  * been caused by the unclean unmount from which we are attempting to recover.
- *
- * This function returns %0 on success and a negative error code on failure.
+ * Returns %0 in case of success, %-EUCLEAN if an unrecoverable corruption is
+ * found, and a negative error code in case of failure.
  */
 struct ubifs_scan_leb *ubifs_recover_leb(struct ubifs_info *c, int lnum,
                                          int offs, void *sbuf, int grouped)
@@ -643,7 +658,8 @@ struct ubifs_scan_leb *ubifs_recover_leb(struct ubifs_info *c, int lnum,
                         goto corrupted;
                 default:
                         dbg_err("unknown");
-                        goto corrupted;
+                        err = -EINVAL;
+                        goto error;
                 }
         }
 
@@ -652,8 +668,13 @@ struct ubifs_scan_leb *ubifs_recover_leb(struct ubifs_info *c, int lnum,
                         clean_buf(c, &buf, lnum, &offs, &len);
                         need_clean = 1;
                 } else {
-                        ubifs_err("corrupt empty space at LEB %d:%d",
-                                  lnum, offs);
+                        int corruption = first_non_ff(buf, len);
+
+                        ubifs_err("corrupt empty space LEB %d:%d, corruption "
+                                  "starts at %d", lnum, offs, corruption);
+                        /* Make sure we dump interesting non-0xFF data */
+                        offs = corruption;
+                        buf += corruption;
                         goto corrupted;
                 }
         }
@@ -813,7 +834,7 @@ struct ubifs_scan_leb *ubifs_recover_log_leb(struct ubifs_info *c, int lnum,
 static int recover_head(const struct ubifs_info *c, int lnum, int offs,
                         void *sbuf)
 {
-        int len, err, need_clean = 0;
+        int len, err;
 
         if (c->min_io_size > 1)
                 len = c->min_io_size;
@@ -827,19 +848,7 @@ static int recover_head(const struct ubifs_info *c, int lnum, int offs,
 
         /* Read at the head location and check it is empty flash */
         err = ubi_read(c->ubi, lnum, sbuf, offs, len);
-        if (err)
-                need_clean = 1;
-        else {
-                uint8_t *p = sbuf;
-
-                while (len--)
-                        if (*p++ != 0xff) {
-                                need_clean = 1;
-                                break;
-                        }
-        }
-
-        if (need_clean) {
+        if (err || !is_empty(sbuf, len)) {
                 dbg_rcvry("cleaning head at %d:%d", lnum, offs);
                 if (offs == 0)
                         return ubifs_leb_unmap(c, lnum);