[03/37] JFFS2: Fix free space leak with in-band cleanmarkers

Greg KH
2008-04-29T17:21:18Z

[-- Attachment #1: jffs2-fix-free-space-leak-with-in-band-cleanmarkers.patch --]
[-- Type: text/plain, Size: 2444 bytes --]

2.6.25-stable review patch. If anyone has any objections, please let us
know.

------------------
From: David Woodhouse <dwmw2@infradead.org>

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.

[Backport of commit 014b164e1392a166fe96e003d2f0e7ad2e2a0bb7]

Signed-off-by: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
fs/jffs2/erase.c | 18 ++++++++----------
1 file changed, 8 insertions(+), 10 deletions(-)

--- a/fs/jffs2/erase.c
+++ b/fs/jffs2/erase.c
@@ -419,9 +419,6 @@ static void jffs2_mark_erased_block(stru
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(stru

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;

down(&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);

--