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path: root/fs/btrfs/extent_io.c
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Diffstat (limited to 'fs/btrfs/extent_io.c')
-rw-r--r--fs/btrfs/extent_io.c10
1 files changed, 8 insertions, 2 deletions
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 0381b6007ae4..0f74262911be 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -3750,7 +3750,7 @@ struct extent_buffer *alloc_extent_buffer(struct extent_io_tree *tree,
}
if (uptodate)
set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
-
+again:
ret = radix_tree_preload(GFP_NOFS & ~__GFP_HIGHMEM);
if (ret)
goto free_eb;
@@ -3760,7 +3760,13 @@ struct extent_buffer *alloc_extent_buffer(struct extent_io_tree *tree,
if (ret == -EEXIST) {
exists = radix_tree_lookup(&tree->buffer,
start >> PAGE_CACHE_SHIFT);
- atomic_inc(&exists->refs);
+ if (!atomic_inc_not_zero(&exists->refs)) {
+ spin_unlock(&tree->buffer_lock);
+ radix_tree_preload_end();
+ synchronize_rcu();
+ exists = NULL;
+ goto again;
+ }
spin_unlock(&tree->buffer_lock);
radix_tree_preload_end();
goto free_eb;