2 files changed, 38 insertions, 9 deletions

diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index a902faab7161..b06d289f998f 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -293,15 +293,24 @@ static int __btrfs_run_defrag_inode(struct btrfs_fs_info *fs_info,
         struct btrfs_key key;
         struct btrfs_ioctl_defrag_range_args range;
         int num_defrag;
+        int index;
+        int ret;
 
         /* get the inode */
         key.objectid = defrag->root;
         btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
         key.offset = (u64)-1;
+
+        index = srcu_read_lock(&fs_info->subvol_srcu);
+
         inode_root = btrfs_read_fs_root_no_name(fs_info, &key);
         if (IS_ERR(inode_root)) {
-                kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
-                return PTR_ERR(inode_root);
+                ret = PTR_ERR(inode_root);
+                goto cleanup;
+        }
+        if (btrfs_root_refs(&inode_root->root_item) == 0) {
+                ret = -ENOENT;
+                goto cleanup;
         }
 
         key.objectid = defrag->ino;
@@ -309,9 +318,10 @@ static int __btrfs_run_defrag_inode(struct btrfs_fs_info *fs_info,
         key.offset = 0;
         inode = btrfs_iget(fs_info->sb, &key, inode_root, NULL);
         if (IS_ERR(inode)) {
-                kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
-                return PTR_ERR(inode);
+                ret = PTR_ERR(inode);
+                goto cleanup;
         }
+        srcu_read_unlock(&fs_info->subvol_srcu, index);
 
         /* do a chunk of defrag */
         clear_bit(BTRFS_INODE_IN_DEFRAG, &BTRFS_I(inode)->runtime_flags);
@@ -346,6 +356,10 @@ static int __btrfs_run_defrag_inode(struct btrfs_fs_info *fs_info,
 
         iput(inode);
         return 0;
+cleanup:
+        srcu_read_unlock(&fs_info->subvol_srcu, index);
+        kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
+        return ret;
 }
 
 /*
diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
index bdbb94f245c9..67783e03d121 100644
--- a/fs/btrfs/scrub.c
+++ b/fs/btrfs/scrub.c
@@ -580,20 +580,29 @@ static int scrub_fixup_readpage(u64 inum, u64 offset, u64 root, void *fixup_ctx)
         int corrected = 0;
         struct btrfs_key key;
         struct inode *inode = NULL;
+        struct btrfs_fs_info *fs_info;
         u64 end = offset + PAGE_SIZE - 1;
         struct btrfs_root *local_root;
+        int srcu_index;
 
         key.objectid = root;
         key.type = BTRFS_ROOT_ITEM_KEY;
         key.offset = (u64)-1;
-        local_root = btrfs_read_fs_root_no_name(fixup->root->fs_info, &key);
-        if (IS_ERR(local_root))
+
+        fs_info = fixup->root->fs_info;
+        srcu_index = srcu_read_lock(&fs_info->subvol_srcu);
+
+        local_root = btrfs_read_fs_root_no_name(fs_info, &key);
+        if (IS_ERR(local_root)) {
+                srcu_read_unlock(&fs_info->subvol_srcu, srcu_index);
                 return PTR_ERR(local_root);
+        }
 
         key.type = BTRFS_INODE_ITEM_KEY;
         key.objectid = inum;
         key.offset = 0;
-        inode = btrfs_iget(fixup->root->fs_info->sb, &key, local_root, NULL);
+        inode = btrfs_iget(fs_info->sb, &key, local_root, NULL);
+        srcu_read_unlock(&fs_info->subvol_srcu, srcu_index);
         if (IS_ERR(inode))
                 return PTR_ERR(inode);
 
@@ -606,7 +615,6 @@ static int scrub_fixup_readpage(u64 inum, u64 offset, u64 root, void *fixup_ctx)
         }
 
         if (PageUptodate(page)) {
-                struct btrfs_fs_info *fs_info;
                 if (PageDirty(page)) {
                         /*
                          * we need to write the data to the defect sector. the
@@ -3180,18 +3188,25 @@ static int copy_nocow_pages_for_inode(u64 inum, u64 offset, u64 root, void *ctx)
         u64 physical_for_dev_replace;
         u64 len;
         struct btrfs_fs_info *fs_info = nocow_ctx->sctx->dev_root->fs_info;
+        int srcu_index;
 
         key.objectid = root;
         key.type = BTRFS_ROOT_ITEM_KEY;
         key.offset = (u64)-1;
+
+        srcu_index = srcu_read_lock(&fs_info->subvol_srcu);
+
         local_root = btrfs_read_fs_root_no_name(fs_info, &key);
-        if (IS_ERR(local_root))
+        if (IS_ERR(local_root)) {
+                srcu_read_unlock(&fs_info->subvol_srcu, srcu_index);
                 return PTR_ERR(local_root);
+        }
 
         key.type = BTRFS_INODE_ITEM_KEY;
         key.objectid = inum;
         key.offset = 0;
         inode = btrfs_iget(fs_info->sb, &key, local_root, NULL);
+        srcu_read_unlock(&fs_info->subvol_srcu, srcu_index);
         if (IS_ERR(inode))
                 return PTR_ERR(inode);