From 09be207d1ba224531a61de9afdc07a125e45318c Mon Sep 17 00:00:00 2001 From: Chris Mason Date: Wed, 7 Nov 2007 21:08:16 -0500 Subject: [PATCH] Btrfs: Fix failure cleanups when allocating extent buffers fail Signed-off-by: Chris Mason --- fs/btrfs/extent_map.c | 56 +++++++++++++++++++++++-------------------- 1 file changed, 30 insertions(+), 26 deletions(-) diff --git a/fs/btrfs/extent_map.c b/fs/btrfs/extent_map.c index b0677c84bb75..c976615dcda3 100644 --- a/fs/btrfs/extent_map.c +++ b/fs/btrfs/extent_map.c @@ -2106,25 +2106,17 @@ static struct extent_buffer *__alloc_extent_buffer(struct extent_map_tree *tree, spin_lock(&tree->lru_lock); eb = find_lru(tree, start, len); - if (eb) { - goto lru_add; - } spin_unlock(&tree->lru_lock); - if (eb) { - memset(eb, 0, sizeof(*eb)); - } else { - eb = kmem_cache_zalloc(extent_buffer_cache, mask); + return eb; } + + eb = kmem_cache_zalloc(extent_buffer_cache, mask); INIT_LIST_HEAD(&eb->lru); eb->start = start; eb->len = len; atomic_set(&eb->refs, 1); - spin_lock(&tree->lru_lock); -lru_add: - add_lru(tree, eb); - spin_unlock(&tree->lru_lock); return eb; } @@ -2151,7 +2143,7 @@ struct extent_buffer *alloc_extent_buffer(struct extent_map_tree *tree, return NULL; if (eb->flags & EXTENT_BUFFER_FILLED) - return eb; + goto lru_add; if (page0) { eb->first_page = page0; @@ -2169,11 +2161,6 @@ struct extent_buffer *alloc_extent_buffer(struct extent_map_tree *tree, p = find_or_create_page(mapping, index, mask | __GFP_HIGHMEM); if (!p) { WARN_ON(1); - /* make sure the free only frees the pages we've - * grabbed a reference on - */ - eb->len = i << PAGE_CACHE_SHIFT; - eb->start &= ~((u64)PAGE_CACHE_SIZE - 1); goto fail; } set_page_extent_mapped(p); @@ -2192,9 +2179,20 @@ struct extent_buffer *alloc_extent_buffer(struct extent_map_tree *tree, if (uptodate) eb->flags |= EXTENT_UPTODATE; eb->flags |= EXTENT_BUFFER_FILLED; + +lru_add: + spin_lock(&tree->lru_lock); + add_lru(tree, eb); + spin_unlock(&tree->lru_lock); return eb; + fail: - free_extent_buffer(eb); + if (!atomic_dec_and_test(&eb->refs)) + return NULL; + for (index = 0; index < i; index++) { + page_cache_release(extent_buffer_page(eb, index)); + } + __free_extent_buffer(eb); return NULL; } EXPORT_SYMBOL(alloc_extent_buffer); @@ -2204,7 +2202,8 @@ struct extent_buffer *find_extent_buffer(struct extent_map_tree *tree, gfp_t mask) { unsigned long num_pages = num_extent_pages(start, len); - unsigned long i; unsigned long index = start >> PAGE_CACHE_SHIFT; + unsigned long i; + unsigned long index = start >> PAGE_CACHE_SHIFT; struct extent_buffer *eb; struct page *p; struct address_space *mapping = tree->mapping; @@ -2215,16 +2214,11 @@ struct extent_buffer *find_extent_buffer(struct extent_map_tree *tree, return NULL; if (eb->flags & EXTENT_BUFFER_FILLED) - return eb; + goto lru_add; for (i = 0; i < num_pages; i++, index++) { p = find_lock_page(mapping, index); if (!p) { - /* make sure the free only frees the pages we've - * grabbed a reference on - */ - eb->len = i << PAGE_CACHE_SHIFT; - eb->start &= ~((u64)PAGE_CACHE_SIZE - 1); goto fail; } set_page_extent_mapped(p); @@ -2245,9 +2239,19 @@ struct extent_buffer *find_extent_buffer(struct extent_map_tree *tree, if (uptodate) eb->flags |= EXTENT_UPTODATE; eb->flags |= EXTENT_BUFFER_FILLED; + +lru_add: + spin_lock(&tree->lru_lock); + add_lru(tree, eb); + spin_unlock(&tree->lru_lock); return eb; fail: - free_extent_buffer(eb); + if (!atomic_dec_and_test(&eb->refs)) + return NULL; + for (index = 0; index < i; index++) { + page_cache_release(extent_buffer_page(eb, index)); + } + __free_extent_buffer(eb); return NULL; } EXPORT_SYMBOL(find_extent_buffer); -- 2.20.1