5 files changed, 34 insertions, 22 deletions

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index c4c94b30c729..162a66bfbffd 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -3106,6 +3106,11 @@ again:
         WARN_ON(ret);
 
         if (i_size_read(inode) > 0) {
+                ret = btrfs_check_trunc_cache_free_space(root,
+                                        &root->fs_info->global_block_rsv);
+                if (ret)
+                        goto out_put;
+
                 ret = btrfs_truncate_free_space_cache(root, trans, path,
                                                       inode);
                 if (ret)
diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c
index 6a8bb9c79674..e53009657f0e 100644
--- a/fs/btrfs/free-space-cache.c
+++ b/fs/btrfs/free-space-cache.c
@@ -197,30 +197,32 @@ int create_free_space_inode(struct btrfs_root *root,
                                          block_group->key.objectid);
 }
 
-int btrfs_truncate_free_space_cache(struct btrfs_root *root,
-                                    struct btrfs_trans_handle *trans,
-                                    struct btrfs_path *path,
-                                    struct inode *inode)
+int btrfs_check_trunc_cache_free_space(struct btrfs_root *root,
+                                       struct btrfs_block_rsv *rsv)
 {
-        struct btrfs_block_rsv *rsv;
         u64 needed_bytes;
-        loff_t oldsize;
-        int ret = 0;
-
-        rsv = trans->block_rsv;
-        trans->block_rsv = &root->fs_info->global_block_rsv;
+        int ret;
 
         /* 1 for slack space, 1 for updating the inode */
         needed_bytes = btrfs_calc_trunc_metadata_size(root, 1) +
                 btrfs_calc_trans_metadata_size(root, 1);
 
-        spin_lock(&trans->block_rsv->lock);
-        if (trans->block_rsv->reserved < needed_bytes) {
-                spin_unlock(&trans->block_rsv->lock);
-                trans->block_rsv = rsv;
-                return -ENOSPC;
-        }
-        spin_unlock(&trans->block_rsv->lock);
+        spin_lock(&rsv->lock);
+        if (rsv->reserved < needed_bytes)
+                ret = -ENOSPC;
+        else
+                ret = 0;
+        spin_unlock(&rsv->lock);
+        return 0;
+}
+
+int btrfs_truncate_free_space_cache(struct btrfs_root *root,
+                                    struct btrfs_trans_handle *trans,
+                                    struct btrfs_path *path,
+                                    struct inode *inode)
+{
+        loff_t oldsize;
+        int ret = 0;
 
         oldsize = i_size_read(inode);
         btrfs_i_size_write(inode, 0);
@@ -232,9 +234,7 @@ int btrfs_truncate_free_space_cache(struct btrfs_root *root,
          */
         ret = btrfs_truncate_inode_items(trans, root, inode,
                                          0, BTRFS_EXTENT_DATA_KEY);
-
         if (ret) {
-                trans->block_rsv = rsv;
                 btrfs_abort_transaction(trans, root, ret);
                 return ret;
         }
@@ -242,7 +242,6 @@ int btrfs_truncate_free_space_cache(struct btrfs_root *root,
         ret = btrfs_update_inode(trans, root, inode);
         if (ret)
                 btrfs_abort_transaction(trans, root, ret);
-        trans->block_rsv = rsv;
 
         return ret;
 }
diff --git a/fs/btrfs/free-space-cache.h b/fs/btrfs/free-space-cache.h
index 4dc17d8809c7..8b7f19f44961 100644
--- a/fs/btrfs/free-space-cache.h
+++ b/fs/btrfs/free-space-cache.h
@@ -54,6 +54,8 @@ int create_free_space_inode(struct btrfs_root *root,
                             struct btrfs_block_group_cache *block_group,
                             struct btrfs_path *path);
 
+int btrfs_check_trunc_cache_free_space(struct btrfs_root *root,
+                                       struct btrfs_block_rsv *rsv);
 int btrfs_truncate_free_space_cache(struct btrfs_root *root,
                                     struct btrfs_trans_handle *trans,
                                     struct btrfs_path *path,
diff --git a/fs/btrfs/inode-map.c b/fs/btrfs/inode-map.c
index 9818d4a3f829..2c66ddbbe670 100644
--- a/fs/btrfs/inode-map.c
+++ b/fs/btrfs/inode-map.c
@@ -429,11 +429,12 @@ int btrfs_save_ino_cache(struct btrfs_root *root,
         num_bytes = trans->bytes_reserved;
         /*
          * 1 item for inode item insertion if need
-         * 3 items for inode item update (in the worst case)
+         * 4 items for inode item update (in the worst case)
+         * 1 items for slack space if we need do truncation
          * 1 item for free space object
          * 3 items for pre-allocation
          */
-        trans->bytes_reserved = btrfs_calc_trans_metadata_size(root, 8);
+        trans->bytes_reserved = btrfs_calc_trans_metadata_size(root, 10);
         ret = btrfs_block_rsv_add(root, trans->block_rsv,
                                   trans->bytes_reserved,
                                   BTRFS_RESERVE_NO_FLUSH);
diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index 5c5b8bb44ee5..395b82031a42 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -3350,6 +3350,11 @@ static int delete_block_group_cache(struct btrfs_fs_info *fs_info,
         }
 
 truncate:
+        ret = btrfs_check_trunc_cache_free_space(root,
+                                                 &fs_info->global_block_rsv);
+        if (ret)
+                goto out;
+
         path = btrfs_alloc_path();
         if (!path) {
                 ret = -ENOMEM;