Btrfs: fix deadlock between alloc_mutex/chunk_mutex

[net-next-2.6.git] / fs / btrfs / extent-tree.c

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 677d5e774fad74c203e0b0a6d1c857948756f45d..db37b867e4f168089ba59d1e801a3637dd579e0b 100644 (file)
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -1505,7 +1505,7 @@ static int do_chunk_alloc(struct btrfs_trans_handle *trans,
        u64 thresh;
        u64 start;
        u64 num_bytes;
-       int ret = 0;
+       int ret = 0, waited = 0;
 
        flags = reduce_alloc_profile(extent_root, flags);
 
@@ -1530,7 +1530,18 @@ static int do_chunk_alloc(struct btrfs_trans_handle *trans,
            space_info->bytes_reserved + alloc_bytes) < thresh)
                goto out;
 
-       mutex_lock(&extent_root->fs_info->chunk_mutex);
+       while (!mutex_trylock(&extent_root->fs_info->chunk_mutex)) {
+               if (!force)
+                       goto out;
+               mutex_unlock(&extent_root->fs_info->alloc_mutex);
+               cond_resched();
+               mutex_lock(&extent_root->fs_info->alloc_mutex);
+               waited = 1;
+       }
+
+       if (waited && space_info->full)
+               goto out_unlock;
+
        ret = btrfs_alloc_chunk(trans, extent_root, &start, &num_bytes, flags);
        if (ret == -ENOSPC) {
 printk("space info full %Lu\n", flags);