Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable

* 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable:
  Btrfs: make sure the chunk allocator doesn't create zero length chunks
  Btrfs: fix data enospc check overflow

fs/btrfs/extent-tree.c

@@ -3235,7 +3235,8 @@ int btrfs_check_data_free_space(struct btrfs_root *root, struct inode *inode,
 				u64 bytes)
 {
 	struct btrfs_space_info *data_sinfo;
-	int ret = 0, committed = 0;
+	u64 used;
+	int ret = 0, committed = 0, flushed = 0;
 
 	/* make sure bytes are sectorsize aligned */
 	bytes = (bytes + root->sectorsize - 1) & ~((u64)root->sectorsize - 1);
@@ -3247,12 +3248,21 @@ int btrfs_check_data_free_space(struct btrfs_root *root, struct inode *inode,
 again:
 	/* make sure we have enough space to handle the data first */
 	spin_lock(&data_sinfo->lock);
-	if (data_sinfo->total_bytes - data_sinfo->bytes_used -
-	    data_sinfo->bytes_delalloc - data_sinfo->bytes_reserved -
-	    data_sinfo->bytes_pinned - data_sinfo->bytes_readonly -
-	    data_sinfo->bytes_may_use - data_sinfo->bytes_super < bytes) {
+	used = data_sinfo->bytes_used + data_sinfo->bytes_delalloc +
+		data_sinfo->bytes_reserved + data_sinfo->bytes_pinned +
+		data_sinfo->bytes_readonly + data_sinfo->bytes_may_use +
+		data_sinfo->bytes_super;
+
+	if (used + bytes > data_sinfo->total_bytes) {
 		struct btrfs_trans_handle *trans;
 
+		if (!flushed) {
+			spin_unlock(&data_sinfo->lock);
+			flush_delalloc(root, data_sinfo);
+			flushed = 1;
+			goto again;
+		}
+
 		/*
 		 * if we don't have enough free bytes in this space then we need
 		 * to alloc a new chunk.

fs/btrfs/volumes.c

@@ -2250,6 +2250,12 @@ static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
 	if (!looped)
 		calc_size = max_t(u64, min_stripe_size, calc_size);
 
+	/*
+	 * we're about to do_div by the stripe_len so lets make sure
+	 * we end up with something bigger than a stripe
+	 */
+	calc_size = max_t(u64, calc_size, stripe_len * 4);
+
 	do_div(calc_size, stripe_len);
 	calc_size *= stripe_len;