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>

1 files changed, 23 insertions, 25 deletions

diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
index c1647f8c1cd0..186ea82b75f7 100644
--- 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;
 }