[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>

diff --git a/fs/jffs2/erase.c b/fs/jffs2/erase.c
index 96d9ad5..bdc6a7b 100644 (file)
--- 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);