[JFFS2] Fix free space leak with in-band cleanmarkers

We were accounting for the cleanmarker by calling jffs2_link_node_ref()
(without locking!), which adjusted both superblock and per-eraseblock
accounting, subtracting the size of the cleanmarker from {jeb,c}->free_size
and adding it to {jeb,c}->used_size.

But only _then_ were we adding the size of the newly-erased block back
to the superblock counts, and we were adding each of jeb->{free,used}_size
to the corresponding superblock counts. Thus, the size of the cleanmarker
was effectively subtracted from the superblock's free_size _twice_.

Fix this, by always adding a full eraseblock size to c->free_size when
we've erased a block. And call jffs2_link_node_ref() under the proper
lock, while we're at it.

Thanks to Alexander Yurchenko and/or Damir Shayhutdinov for (almost)
pinpointing the problem.

Signed-off-by: David Woodhouse <dwmw2@infradead.org>

1 files changed, 8 insertions, 10 deletions

diff --git a/fs/jffs2/erase.c b/fs/jffs2/erase.c
index 96d9ad56e573..bdc6a7bec802 100644
--- a/fs/jffs2/erase.c
+++ b/fs/jffs2/erase.c
@@ -419,9 +419,6 @@ static void jffs2_mark_erased_block(struct jffs2_sb_info *c, struct jffs2_eraseb
                         if (jffs2_write_nand_cleanmarker(c, jeb))
                                 goto filebad;
                 }
-
-                /* Everything else got zeroed before the erase */
-                jeb->free_size = c->sector_size;
         } else {
 
                 struct kvec vecs[1];
@@ -449,18 +446,19 @@ static void jffs2_mark_erased_block(struct jffs2_sb_info *c, struct jffs2_eraseb
 
                         goto filebad;
                 }
-
-                /* Everything else got zeroed before the erase */
-                jeb->free_size = c->sector_size;
-                /* FIXME Special case for cleanmarker in empty block */
-                jffs2_link_node_ref(c, jeb, jeb->offset | REF_NORMAL, c->cleanmarker_size, NULL);
         }
+        /* Everything else got zeroed before the erase */
+        jeb->free_size = c->sector_size;
 
         mutex_lock(&c->erase_free_sem);
         spin_lock(&c->erase_completion_lock);
+
         c->erasing_size -= c->sector_size;
-        c->free_size += jeb->free_size;
-        c->used_size += jeb->used_size;
+        c->free_size += c->sector_size;
+
+        /* Account for cleanmarker now, if it's in-band */
+        if (c->cleanmarker_size && !jffs2_cleanmarker_oob(c))
+                jffs2_link_node_ref(c, jeb, jeb->offset | REF_NORMAL, c->cleanmarker_size, NULL);
 
         jffs2_dbg_acct_sanity_check_nolock(c,jeb);
         jffs2_dbg_acct_paranoia_check_nolock(c, jeb);