Btrfs: cleanup the code of copy_nocow_pages_for_inode()

- It make no sense that we continue to do something after the error
  happened, just go back with this patch.
- remove some check of copy_nocow_pages_for_inode(), such as page check
  after write, inode check in the end of the function, because we are
  sure they exist.
- remove the unnecessary goto in the return value check of the write

Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>

diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
index c1647f8..186ea82 100644 (file)
--- a/fs/btrfs/scrub.c
+++ b/fs/btrfs/scrub.c
@@ -3199,16 +3199,18 @@ out:
 
 static int copy_nocow_pages_for_inode(u64 inum, u64 offset, u64 root, void *ctx)
 {
-       unsigned long index;
        struct scrub_copy_nocow_ctx *nocow_ctx = ctx;
-       int ret = 0;
+       struct btrfs_fs_info *fs_info = nocow_ctx->sctx->dev_root->fs_info;
        struct btrfs_key key;
-       struct inode *inode = NULL;
+       struct inode *inode;
+       struct page *page;
        struct btrfs_root *local_root;
        u64 physical_for_dev_replace;
        u64 len;
-       struct btrfs_fs_info *fs_info = nocow_ctx->sctx->dev_root->fs_info;
+       unsigned long index;
        int srcu_index;
+       int ret;
+       int err;
 
        key.objectid = root;
        key.type = BTRFS_ROOT_ITEM_KEY;
@@ -3230,19 +3232,17 @@ static int copy_nocow_pages_for_inode(u64 inum, u64 offset, u64 root, void *ctx)
        if (IS_ERR(inode))
                return PTR_ERR(inode);
 
+       ret = 0;
        physical_for_dev_replace = nocow_ctx->physical_for_dev_replace;
        len = nocow_ctx->len;
        while (len >= PAGE_CACHE_SIZE) {
-               struct page *page = NULL;
-               int ret_sub;
-
                index = offset >> PAGE_CACHE_SHIFT;
 
                page = find_or_create_page(inode->i_mapping, index, GFP_NOFS);
                if (!page) {
                        pr_err("find_or_create_page() failed\n");
                        ret = -ENOMEM;
-                       goto next_page;
+                       goto out;
                }
 
                if (PageUptodate(page)) {
@@ -3250,12 +3250,12 @@ static int copy_nocow_pages_for_inode(u64 inum, u64 offset, u64 root, void *ctx)
                                goto next_page;
                } else {
                        ClearPageError(page);
-                       ret_sub = extent_read_full_page(&BTRFS_I(inode)->
+                       err = extent_read_full_page(&BTRFS_I(inode)->
                                                         io_tree,
                                                        page, btrfs_get_extent,
                                                        nocow_ctx->mirror_num);
-                       if (ret_sub) {
-                               ret = ret_sub;
+                       if (err) {
+                               ret = err;
                                goto next_page;
                        }
                        lock_page(page);
@@ -3264,25 +3264,23 @@ static int copy_nocow_pages_for_inode(u64 inum, u64 offset, u64 root, void *ctx)
                                goto next_page;
                        }
                }
-               ret_sub = write_page_nocow(nocow_ctx->sctx,
-                                          physical_for_dev_replace, page);
-               if (ret_sub) {
-                       ret = ret_sub;
-                       goto next_page;
-               }
-
+               err = write_page_nocow(nocow_ctx->sctx,
+                                      physical_for_dev_replace, page);
+               if (err)
+                       ret = err;
 next_page:
-               if (page) {
-                       unlock_page(page);
-                       put_page(page);
-               }
+               unlock_page(page);
+               page_cache_release(page);
+
+               if (ret)
+                       break;
+
                offset += PAGE_CACHE_SIZE;
                physical_for_dev_replace += PAGE_CACHE_SIZE;
                len -= PAGE_CACHE_SIZE;
        }
-
-       if (inode)
-               iput(inode);
+out:
+       iput(inode);
        return ret;
 }