From 9dced186f934648bb7796ad3301cfc2563e2ad6e Mon Sep 17 00:00:00 2001 From: Miao Xie Date: Fri, 25 Oct 2013 17:33:36 +0800 Subject: [PATCH] Btrfs: fix the free space write out failure when there is no data space After running space balance on a new fs, the fs check program outputed the following warning message: free space inode generation (0) did not match free space cache generation (20) Steps to reproduce: # mkfs.btrfs -f # mount # btrfs balance start # umount # btrfs check It was because there was no data space after the space balance, and the free space write out task didn't try to allocate a new data chunk for the free space inode when doing the reservation. So the data space reservation failed, and in order to tell the free space loader that this free space inode could not be trusted, the generation of the free space inode wasn't updated. Then the check program found this problem and outputed the above message. But in fact, it is safe that we try to allocate a new data chunk when we find the data space is not enough. The patch fixes the above problem by this way. Signed-off-by: Miao Xie Signed-off-by: Josef Bacik Signed-off-by: Chris Mason --- fs/btrfs/extent-tree.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index 4595a65..3aa5270 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -3621,10 +3621,9 @@ int btrfs_check_data_free_space(struct inode *inode, u64 bytes) /* make sure bytes are sectorsize aligned */ bytes = ALIGN(bytes, root->sectorsize); - if (root == root->fs_info->tree_root || - BTRFS_I(inode)->location.objectid == BTRFS_FREE_INO_OBJECTID) { - alloc_chunk = 0; + if (btrfs_is_free_space_inode(inode)) { committed = 1; + ASSERT(current->journal_info); } data_sinfo = fs_info->data_sinfo; @@ -3652,6 +3651,16 @@ again: spin_unlock(&data_sinfo->lock); alloc: alloc_target = btrfs_get_alloc_profile(root, 1); + /* + * It is ugly that we don't call nolock join + * transaction for the free space inode case here. + * But it is safe because we only do the data space + * reservation for the free space cache in the + * transaction context, the common join transaction + * just increase the counter of the current transaction + * handler, doesn't try to acquire the trans_lock of + * the fs. + */ trans = btrfs_join_transaction(root); if (IS_ERR(trans)) return PTR_ERR(trans); -- 2.7.4