From 3e04e7f10b68999e0d8321516ea19d9d5b044dee Mon Sep 17 00:00:00 2001 From: Josef Bacik Date: Wed, 6 Feb 2013 16:49:15 -0500 Subject: [PATCH] Btrfs: handle errors in compression submission path I noticed we would deadlock if we aborted a transaction while doing compressed io. This is because we don't unlock our pages if something goes horribly wrong. To fix this we need to make sure that we call extent_clear_unlock_delalloc in order to unlock all the pages. If we have to cow in the async submission thread we need to make sure to unlock our locked_page as the cow error path will not unlock the locked page as it depends on the caller to unlock that page. With this patch we no longer deadlock on the page lock when we have an aborted transaction. Thanks, Signed-off-by: Josef Bacik --- fs/btrfs/inode.c | 38 ++++++++++++++++++++++++++++---------- 1 file changed, 28 insertions(+), 10 deletions(-) diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 2dc59734e071..348b7bb920ef 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -608,7 +608,7 @@ static noinline int submit_compressed_extents(struct inode *inode, if (list_empty(&async_cow->extents)) return 0; - +again: while (!list_empty(&async_cow->extents)) { async_extent = list_entry(async_cow->extents.next, struct async_extent, list); @@ -648,6 +648,8 @@ retry: async_extent->ram_size - 1, btrfs_get_extent, WB_SYNC_ALL); + else if (ret) + unlock_page(async_cow->locked_page); kfree(async_extent); cond_resched(); continue; @@ -672,6 +674,7 @@ retry: if (ret) { int i; + for (i = 0; i < async_extent->nr_pages; i++) { WARN_ON(async_extent->pages[i]->mapping); page_cache_release(async_extent->pages[i]); @@ -679,12 +682,10 @@ retry: kfree(async_extent->pages); async_extent->nr_pages = 0; async_extent->pages = NULL; - unlock_extent(io_tree, async_extent->start, - async_extent->start + - async_extent->ram_size - 1); + if (ret == -ENOSPC) goto retry; - goto out_free; /* JDM: Requeue? */ + goto out_free; } /* @@ -696,7 +697,8 @@ retry: async_extent->ram_size - 1, 0); em = alloc_extent_map(); - BUG_ON(!em); /* -ENOMEM */ + if (!em) + goto out_free_reserve; em->start = async_extent->start; em->len = async_extent->ram_size; em->orig_start = em->start; @@ -728,6 +730,9 @@ retry: async_extent->ram_size - 1, 0); } + if (ret) + goto out_free_reserve; + ret = btrfs_add_ordered_extent_compress(inode, async_extent->start, ins.objectid, @@ -735,7 +740,8 @@ retry: ins.offset, BTRFS_ORDERED_COMPRESSED, async_extent->compress_type); - BUG_ON(ret); /* -ENOMEM */ + if (ret) + goto out_free_reserve; /* * clear dirty, set writeback and unlock the pages. @@ -756,18 +762,30 @@ retry: ins.objectid, ins.offset, async_extent->pages, async_extent->nr_pages); - - BUG_ON(ret); /* -ENOMEM */ alloc_hint = ins.objectid + ins.offset; kfree(async_extent); + if (ret) + goto out; cond_resched(); } ret = 0; out: return ret; +out_free_reserve: + btrfs_free_reserved_extent(root, ins.objectid, ins.offset); out_free: + extent_clear_unlock_delalloc(inode, &BTRFS_I(inode)->io_tree, + async_extent->start, + async_extent->start + + async_extent->ram_size - 1, + NULL, EXTENT_CLEAR_UNLOCK_PAGE | + EXTENT_CLEAR_UNLOCK | + EXTENT_CLEAR_DELALLOC | + EXTENT_CLEAR_DIRTY | + EXTENT_SET_WRITEBACK | + EXTENT_END_WRITEBACK); kfree(async_extent); - goto out; + goto again; } static u64 get_extent_allocation_hint(struct inode *inode, u64 start,