f2fs: handle errors correctly during f2fs_reserve_block

The get_dnode_of_data nullifies inode and node page when error is occurred.

There are two cases that passes inode page into get_dnode_of_data().

1. make_empty_dir()
    -> get_new_data_page()
      -> f2fs_reserve_block(ipage)
	-> get_dnode_of_data()

2. f2fs_convert_inline_data()
    -> __f2fs_convert_inline_data()
      -> f2fs_reserve_block(ipage)
	-> get_dnode_of_data()

This patch adds correct error handling codes when get_dnode_of_data() returns
an error.

At first, f2fs_reserve_block() calls f2fs_put_dnode() whenever reserve_new_block
returns an error.
So, the rule of f2fs_reserve_block() is to nullify inode page when there is any
error internally.

Finally, two callers of f2fs_reserve_block() should call f2fs_put_dnode()
appropriately if they got an error since successful f2fs_reserve_block().

Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

3 files changed, 26 insertions, 16 deletions

diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index fc7a28c5ad23..63d190264a36 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -258,13 +258,16 @@ int f2fs_reserve_block(struct dnode_of_data *dn, pgoff_t index)
         bool need_put = dn->inode_page ? false : true;
         int err;
 
+        /* if inode_page exists, index should be zero */
+        f2fs_bug_on(!need_put && index);
+
         err = get_dnode_of_data(dn, index, ALLOC_NODE);
         if (err)
                 return err;
+
         if (dn->data_blkaddr == NULL_ADDR)
                 err = reserve_new_block(dn);
-
-        if (need_put)
+        if (err || need_put)
                 f2fs_put_dnode(dn);
         return err;
 }
@@ -510,10 +513,10 @@ repeat:
  *
  * Also, caller should grab and release a rwsem by calling f2fs_lock_op() and
  * f2fs_unlock_op().
- * Note that, npage is set only by make_empty_dir.
+ * Note that, ipage is set only by make_empty_dir.
  */
 struct page *get_new_data_page(struct inode *inode,
-                struct page *npage, pgoff_t index, bool new_i_size)
+                struct page *ipage, pgoff_t index, bool new_i_size)
 {
         struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
         struct address_space *mapping = inode->i_mapping;
@@ -521,14 +524,16 @@ struct page *get_new_data_page(struct inode *inode,
         struct dnode_of_data dn;
         int err;
 
-        set_new_dnode(&dn, inode, npage, npage, 0);
+        set_new_dnode(&dn, inode, ipage, NULL, 0);
         err = f2fs_reserve_block(&dn, index);
         if (err)
                 return ERR_PTR(err);
 repeat:
         page = grab_cache_page(mapping, index);
-        if (!page)
-                return ERR_PTR(-ENOMEM);
+        if (!page) {
+                err = -ENOMEM;
+                goto put_err;
+        }
 
         if (PageUptodate(page))
                 return page;
@@ -540,11 +545,13 @@ repeat:
                 err = f2fs_submit_page_bio(sbi, page, dn.data_blkaddr,
                                                                 READ_SYNC);
                 if (err)
-                        return ERR_PTR(err);
+                        goto put_err;
+
                 lock_page(page);
                 if (unlikely(!PageUptodate(page))) {
                         f2fs_put_page(page, 1);
-                        return ERR_PTR(-EIO);
+                        err = -EIO;
+                        goto put_err;
                 }
                 if (unlikely(page->mapping != mapping)) {
                         f2fs_put_page(page, 1);
@@ -560,6 +567,10 @@ repeat:
                 mark_inode_dirty_sync(inode);
         }
         return page;
+
+put_err:
+        f2fs_put_dnode(&dn);
+        return ERR_PTR(err);
 }
 
 static int __allocate_data_block(struct dnode_of_data *dn)
diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c
index 6da77e5c753b..f815ca0c5819 100644
--- a/fs/f2fs/dir.c
+++ b/fs/f2fs/dir.c
@@ -342,11 +342,11 @@ static struct page *init_inode_metadata(struct inode *inode,
 
                 err = f2fs_init_acl(inode, dir, page);
                 if (err)
-                        goto error;
+                        goto put_error;
 
                 err = f2fs_init_security(inode, dir, name, page);
                 if (err)
-                        goto error;
+                        goto put_error;
 
                 wait_on_page_writeback(page);
         } else {
@@ -370,8 +370,9 @@ static struct page *init_inode_metadata(struct inode *inode,
         }
         return page;
 
-error:
+put_error:
         f2fs_put_page(page, 1);
+error:
         remove_inode_page(inode);
         return ERR_PTR(err);
 }
diff --git a/fs/f2fs/inline.c b/fs/f2fs/inline.c
index 2a756e57aed9..688305afbc74 100644
--- a/fs/f2fs/inline.c
+++ b/fs/f2fs/inline.c
@@ -81,10 +81,9 @@ static int __f2fs_convert_inline_data(struct inode *inode, struct page *page)
          * i_addr[0] is not used for inline data,
          * so reserving new block will not destroy inline data
          */
-        set_new_dnode(&dn, inode, ipage, ipage, 0);
+        set_new_dnode(&dn, inode, ipage, NULL, 0);
         err = f2fs_reserve_block(&dn, 0);
         if (err) {
-                f2fs_put_page(ipage, 1);
                 f2fs_unlock_op(sbi);
                 return err;
         }
@@ -111,9 +110,8 @@ static int __f2fs_convert_inline_data(struct inode *inode, struct page *page)
         stat_dec_inline_inode(inode);
 
         sync_inode_page(&dn);
-        f2fs_put_page(ipage, 1);
+        f2fs_put_dnode(&dn);
         f2fs_unlock_op(sbi);
-
         return err;
 }