Make sure extent conversion after DIO happens while i_dio_count is still
elevated so that inode_dio_wait() waits until extent conversion is done.
This removes the need for explicit waiting for extent conversion in some
cases.
Reviewed-by: Zheng Liu <wenqing.lz@xxxxxxxxxx>
Signed-off-by: Jan Kara <jack@xxxxxxx>
---
fs/ext4/inode.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 1f9a8f9..4273b4d 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -3028,11 +3028,18 @@ static ssize_t ext4_ext_direct_IO(int rw, struct kiocb *iocb,
BUG_ON(iocb->private == NULL);
+ /*
+ * Make all waiters for direct IO properly wait also for extent
+ * conversion. This also disallows race between truncate() and
+ * overwrite DIO as i_dio_count needs to be incremented under i_mutex.
+ */
+ if (rw == WRITE)
+ atomic_inc(&inode->i_dio_count);
+
/* If we do a overwrite dio, i_mutex locking can be released */
overwrite = *((int *)iocb->private);
if (overwrite) {
- atomic_inc(&inode->i_dio_count);
down_read(&EXT4_I(inode)->i_data_sem);
mutex_unlock(&inode->i_mutex);
}
@@ -3135,9 +3142,10 @@ static ssize_t ext4_ext_direct_IO(int rw, struct kiocb *iocb,
}
retake_lock:
+ if (rw == WRITE)
+ inode_dio_done(inode);
/* take i_mutex locking again if we do a ovewrite dio */
if (overwrite) {
- inode_dio_done(inode);
up_read(&EXT4_I(inode)->i_data_sem);
mutex_lock(&inode->i_mutex);
}
--
1.8.1.4
--
To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
