3 files changed, 22 insertions, 19 deletions

diff --git a/fs/ubifs/gc.c b/fs/ubifs/gc.c
index d70937b3f8e9..ded29f6224c2 100644
--- a/fs/ubifs/gc.c
+++ b/fs/ubifs/gc.c
@@ -100,6 +100,10 @@ static int switch_gc_head(struct ubifs_info *c)
         if (err)
                 return err;
 
+        err = ubifs_wbuf_sync_nolock(wbuf);
+        if (err)
+                return err;
+
         err = ubifs_add_bud_to_log(c, GCHD, gc_lnum, 0);
         if (err)
                 return err;
diff --git a/fs/ubifs/io.c b/fs/ubifs/io.c
index 67bbde3550cf..166951e0dcd3 100644
--- a/fs/ubifs/io.c
+++ b/fs/ubifs/io.c
@@ -452,8 +452,8 @@ int ubifs_wbuf_sync_nolock(struct ubifs_wbuf *wbuf)
  * @dtype: data type
  *
  * This function targets the write-buffer to logical eraseblock @lnum:@offs.
- * The write-buffer is synchronized if it is not empty. Returns zero in case of
- * success and a negative error code in case of failure.
+ * The write-buffer has to be empty. Returns zero in case of success and a
+ * negative error code in case of failure.
  */
 int ubifs_wbuf_seek_nolock(struct ubifs_wbuf *wbuf, int lnum, int offs,
                            int dtype)
@@ -465,13 +465,7 @@ int ubifs_wbuf_seek_nolock(struct ubifs_wbuf *wbuf, int lnum, int offs,
         ubifs_assert(offs >= 0 && offs <= c->leb_size);
         ubifs_assert(offs % c->min_io_size == 0 && !(offs & 7));
         ubifs_assert(lnum != wbuf->lnum);
-
-        if (wbuf->used > 0) {
-                int err = ubifs_wbuf_sync_nolock(wbuf);
-
-                if (err)
-                        return err;
-        }
+        ubifs_assert(wbuf->used == 0);
 
         spin_lock(&wbuf->lock);
         wbuf->lnum = lnum;
diff --git a/fs/ubifs/journal.c b/fs/ubifs/journal.c
index ce55a4807cdc..34b1679e6e3a 100644
--- a/fs/ubifs/journal.c
+++ b/fs/ubifs/journal.c
@@ -141,14 +141,8 @@ again:
          * LEB with some empty space.
          */
         lnum = ubifs_find_free_space(c, len, &offs, squeeze);
-        if (lnum >= 0) {
-                /* Found an LEB, add it to the journal head */
-                err = ubifs_add_bud_to_log(c, jhead, lnum, offs);
-                if (err)
-                        goto out_return;
-                /* A new bud was successfully allocated and added to the log */
+        if (lnum >= 0)
                 goto out;
-        }
 
         err = lnum;
         if (err != -ENOSPC)
@@ -203,12 +197,23 @@ again:
                 return 0;
         }
 
-        err = ubifs_add_bud_to_log(c, jhead, lnum, 0);
-        if (err)
-                goto out_return;
         offs = 0;
 
 out:
+        /*
+         * Make sure we synchronize the write-buffer before we add the new bud
+         * to the log. Otherwise we may have a power cut after the log
+         * reference node for the last bud (@lnum) is written but before the
+         * write-buffer data are written to the next-to-last bud
+         * (@wbuf->lnum). And the effect would be that the recovery would see
+         * that there is corruption in the next-to-last bud.
+         */
+        err = ubifs_wbuf_sync_nolock(wbuf);
+        if (err)
+                goto out_return;
+        err = ubifs_add_bud_to_log(c, jhead, lnum, offs);
+        if (err)
+                goto out_return;
         err = ubifs_wbuf_seek_nolock(wbuf, lnum, offs, wbuf->dtype);
         if (err)
                 goto out_unlock;