ext3: add writepage sanity checks

- There is theoretical possibility to perform writepage on
   RO superblock. Add explicit check for what case.
- Page must being locked before writepage.

Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: Jan Kara <jack@suse.cz>

1 files changed, 7 insertions, 0 deletions

diff --git a/fs/ext3/inode.c b/fs/ext3/inode.c
index c0ff9d6ffde6..eda9121d7d57 100644
--- a/fs/ext3/inode.c
+++ b/fs/ext3/inode.c
@@ -1528,6 +1528,7 @@ static int ext3_ordered_writepage(struct page *page,
         int err;
 
         J_ASSERT(PageLocked(page));
+        WARN_ON_ONCE(IS_RDONLY(inode));
 
         /*
          * We give up here if we're reentered, because it might be for a
@@ -1600,6 +1601,9 @@ static int ext3_writeback_writepage(struct page *page,
         int ret = 0;
         int err;
 
+        J_ASSERT(PageLocked(page));
+        WARN_ON_ONCE(IS_RDONLY(inode));
+
         if (ext3_journal_current_handle())
                 goto out_fail;
 
@@ -1642,6 +1646,9 @@ static int ext3_journalled_writepage(struct page *page,
         int ret = 0;
         int err;
 
+        J_ASSERT(PageLocked(page));
+        WARN_ON_ONCE(IS_RDONLY(inode));
+
         if (ext3_journal_current_handle())
                 goto no_write;