f2fs: check truncation of mapping after lock_page

We call lock_page when we need to update a page after readpage.
Between grab and lock page, the page can be truncated by other thread.
So, we should check the page after lock_page whether it was truncated or not.

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

1 files changed, 15 insertions, 3 deletions

diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index eba7e84d1ffd..2db9380f5dda 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -240,7 +240,7 @@ struct page *get_lock_data_page(struct inode *inode, pgoff_t index)
 
         if (dn.data_blkaddr == NULL_ADDR)
                 return ERR_PTR(-ENOENT);
-
+repeat:
         page = grab_cache_page(mapping, index);
         if (!page)
                 return ERR_PTR(-ENOMEM);
@@ -260,6 +260,10 @@ struct page *get_lock_data_page(struct inode *inode, pgoff_t index)
                 f2fs_put_page(page, 1);
                 return ERR_PTR(-EIO);
         }
+        if (page->mapping != mapping) {
+                f2fs_put_page(page, 1);
+                goto repeat;
+        }
         return page;
 }
 
@@ -291,7 +295,7 @@ struct page *get_new_data_page(struct inode *inode, pgoff_t index,
                 }
         }
         f2fs_put_dnode(&dn);
-
+repeat:
         page = grab_cache_page(mapping, index);
         if (!page)
                 return ERR_PTR(-ENOMEM);
@@ -311,6 +315,10 @@ struct page *get_new_data_page(struct inode *inode, pgoff_t index,
                         f2fs_put_page(page, 1);
                         return ERR_PTR(-EIO);
                 }
+                if (page->mapping != mapping) {
+                        f2fs_put_page(page, 1);
+                        goto repeat;
+                }
         }
 
         if (new_i_size &&
@@ -611,7 +619,7 @@ static int f2fs_write_begin(struct file *file, struct address_space *mapping,
         *fsdata = NULL;
 
         f2fs_balance_fs(sbi);
-
+repeat:
         page = grab_cache_page_write_begin(mapping, index, flags);
         if (!page)
                 return -ENOMEM;
@@ -656,6 +664,10 @@ static int f2fs_write_begin(struct file *file, struct address_space *mapping,
                         f2fs_put_page(page, 1);
                         return -EIO;
                 }
+                if (page->mapping != mapping) {
+                        f2fs_put_page(page, 1);
+                        goto repeat;
+                }
         }
 out:
         SetPageUptodate(page);