Commit 25e293c2 authored Dec 26, 2013 by Wang Shilong Committed by Chris Mason Jan 28, 2014

Btrfs: fix an oops when we fail to merge reloc roots



Previously, we will free reloc root memory and then force filesystem
to be readonly. The problem is that there may be another thread commiting
transaction which will try to access freed reloc root during merging reloc
roots process.

To keep consistency snapshots shared space, we should allow snapshot
finished if possible, so here we don't free reloc root memory.

signed-off-by: Wang Shilong <wangsl.fnst@cn.fujitsu.com>

Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>

parent dc4103f9

fs/btrfs/relocation.c

+3 −7

Original line number	Diff line number	Diff line
		@@ -2311,9 +2311,6 @@ void free_reloc_roots(struct list_head *list)
		reloc_root = list_entry(list->next, struct btrfs_root,
		root_list);
		__del_reloc_root(reloc_root);
		free_extent_buffer(reloc_root->node);
		free_extent_buffer(reloc_root->commit_root);
		kfree(reloc_root);
		}
		}

		@@ -2355,10 +2352,9 @@ again:

		ret = merge_reloc_root(rc, root);
		if (ret) {
		__del_reloc_root(reloc_root);
		free_extent_buffer(reloc_root->node);
		free_extent_buffer(reloc_root->commit_root);
		kfree(reloc_root);
		if (list_empty(&reloc_root->root_list))
		list_add_tail(&reloc_root->root_list,
		&reloc_roots);
		goto out;
		}
		} else {

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