[JFFS2] Check whether garbage-collection actually obsoleted its victim.
In OLPC trac #4184 we found a case where a corrupted node didn't
actually get obsoleted when we tried to garbage-collect it. So we wrote
out many million copies of it, in repeated attempts to obsolete it,
until the flash became full. Don't Do That.
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
diff --git a/fs/jffs2/gc.c b/fs/jffs2/gc.c
index eded819..95be264 100644
--- a/fs/jffs2/gc.c
+++ b/fs/jffs2/gc.c
@@ -122,6 +122,7 @@
struct jffs2_inode_cache *ic;
struct jffs2_eraseblock *jeb;
struct jffs2_raw_node_ref *raw;
+ uint32_t gcblock_dirty;
int ret = 0, inum, nlink;
int xattr = 0;
@@ -236,6 +237,7 @@
}
raw = jeb->gc_node;
+ gcblock_dirty = jeb->dirty_size;
while(ref_obsolete(raw)) {
D1(printk(KERN_DEBUG "Node at 0x%08x is obsolete... skipping\n", ref_offset(raw)));
@@ -282,7 +284,7 @@
} else {
ret = jffs2_garbage_collect_xattr_ref(c, (struct jffs2_xattr_ref *)ic, raw);
}
- goto release_sem;
+ goto test_gcnode;
}
#endif
@@ -376,7 +378,7 @@
if (ret != -EBADFD) {
spin_unlock(&c->inocache_lock);
- goto release_sem;
+ goto test_gcnode;
}
/* Fall through if it wanted us to, with inocache_lock held */
@@ -407,6 +409,14 @@
jffs2_gc_release_inode(c, f);
+ test_gcnode:
+ if (jeb->dirty_size == gcblock_dirty && !ref_obsolete(jeb->gc_node)) {
+ /* Eep. This really should never happen. GC is broken */
+ printk(KERN_ERR "Error garbage collecting node at %08x!\n", ref_offset(jeb->gc_node));
+ ret = -ENOSPC;
+ } else if (ref_offset(jeb->gc_node) == 0x1c616bdc)
+ printk(KERN_ERR "Wheee. Correctly GC'd node at %08x\n", ref_offset(jeb->gc_node));
+
release_sem:
up(&c->alloc_sem);