ext4: serialize dio nonlocked reads with defrag workers

Inode's block defrag and ext4_change_inode_journal_flag() may
affect nonlocked DIO reads result, so proper synchronization
required.

- Add missed inode_dio_wait() calls where appropriate
- Check inode state under extra i_dio_count reference.

Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

1 files changed, 5 insertions, 0 deletions

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 09d0488e9a15..bdd399bc2abf 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -4720,6 +4720,10 @@ int ext4_change_inode_journal_flag(struct inode *inode, int val)
                         return err;
         }
 
+        /* Wait for all existing dio workers */
+        ext4_inode_block_unlocked_dio(inode);
+        inode_dio_wait(inode);
+
         jbd2_journal_lock_updates(journal);
 
         /*
@@ -4739,6 +4743,7 @@ int ext4_change_inode_journal_flag(struct inode *inode, int val)
         ext4_set_aops(inode);
 
         jbd2_journal_unlock_updates(journal);
+        ext4_inode_resume_unlocked_dio(inode);
 
         /* Finally we can mark the inode as dirty. */