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Commit 2665ea84 authored by David Woodhouse's avatar David Woodhouse
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[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: default avatarDavid Woodhouse <dwmw2@infradead.org>
parent 85becc53

fs/jffs2/gc.c

+12 −2
Original line number Diff line number Diff line
@@ -122,6 +122,7 @@ int jffs2_garbage_collect_pass(struct jffs2_sb_info *c) 
	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 @@ int jffs2_garbage_collect_pass(struct jffs2_sb_info *c) 
	}



	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		D1(printk(KERN_DEBUG "Node at 0x%08x is obsolete...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 @@ int jffs2_garbage_collect_pass(struct jffs2_sb_info *c) 
		} 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 @@ int jffs2_garbage_collect_pass(struct jffs2_sb_info *c) 


		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 @@ int jffs2_garbage_collect_pass(struct jffs2_sb_info *c) 


	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);