ext4: Fix data exposure after failed AIO DIO

When AIO DIO fails e.g. due to IO error, we must not convert unwritten
extents as that will expose uninitialized data. Handle this case
by clearing unwritten flag from io_end in case of error and thus
preventing extent conversion.

Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <david@fromorbit.com>

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 0662b285dc8a71982a54e5895d58d797c7bcf6a4..56c12df107ab5f7c785c845a0a8bec42a50bcd75 100644 (file)
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -1504,15 +1504,6 @@ static inline int ext4_valid_inum(struct super_block *sb, unsigned long ino)
                 ino <= le32_to_cpu(EXT4_SB(sb)->s_es->s_inodes_count));
 }
 
-static inline void ext4_set_io_unwritten_flag(struct inode *inode,
-                                             struct ext4_io_end *io_end)
-{
-       if (!(io_end->flag & EXT4_IO_END_UNWRITTEN)) {
-               io_end->flag |= EXT4_IO_END_UNWRITTEN;
-               atomic_inc(&EXT4_I(inode)->i_unwritten);
-       }
-}
-
 static inline ext4_io_end_t *ext4_inode_aio(struct inode *inode)
 {
        return inode->i_private;
@@ -3293,6 +3284,27 @@ extern struct mutex ext4__aio_mutex[EXT4_WQ_HASH_SZ];
 extern int ext4_resize_begin(struct super_block *sb);
 extern void ext4_resize_end(struct super_block *sb);
 
+static inline void ext4_set_io_unwritten_flag(struct inode *inode,
+                                             struct ext4_io_end *io_end)
+{
+       if (!(io_end->flag & EXT4_IO_END_UNWRITTEN)) {
+               io_end->flag |= EXT4_IO_END_UNWRITTEN;
+               atomic_inc(&EXT4_I(inode)->i_unwritten);
+       }
+}
+
+static inline void ext4_clear_io_unwritten_flag(ext4_io_end_t *io_end)
+{
+       struct inode *inode = io_end->inode;
+
+       if (io_end->flag & EXT4_IO_END_UNWRITTEN) {
+               io_end->flag &= ~EXT4_IO_END_UNWRITTEN;
+               /* Wake up anyone waiting on unwritten extent conversion */
+               if (atomic_dec_and_test(&EXT4_I(inode)->i_unwritten))
+                       wake_up_all(ext4_ioend_wq(inode));
+       }
+}
+
 #endif /* __KERNEL__ */
 
 #define EFSBADCRC      EBADMSG         /* Bad CRC detected */

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 9db04dd9b88a6e45782485ccf28844804294b103..2b98171a943296382d40ba4d6e6e1f6a996e129a 100644 (file)
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -3166,9 +3166,6 @@ static int ext4_end_io_dio(struct kiocb *iocb, loff_t offset,
 {
         ext4_io_end_t *io_end = iocb->private;
 
-       if (size <= 0)
-               return 0;
-
        /* if not async direct IO just return */
        if (!io_end)
                return 0;
@@ -3179,6 +3176,14 @@ static int ext4_end_io_dio(struct kiocb *iocb, loff_t offset,
                  size);
 
        iocb->private = NULL;
+       /*
+        * Error during AIO DIO. We cannot convert unwritten extents as the
+        * data was not written. Just clear the unwritten flag and drop io_end.
+        */
+       if (size <= 0) {
+               ext4_clear_io_unwritten_flag(io_end);
+               size = 0;
+       }
        io_end->offset = offset;
        io_end->size = size;
        ext4_put_io_end(io_end);
@@ -3306,16 +3311,6 @@ static ssize_t ext4_ext_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
        if (io_end) {
                ext4_inode_aio_set(inode, NULL);
                ext4_put_io_end(io_end);
-               /*
-                * When no IO was submitted ext4_end_io_dio() was not
-                * called so we have to put iocb's reference.
-                */
-               if (ret <= 0 && ret != -EIOCBQUEUED && iocb->private) {
-                       WARN_ON(iocb->private != io_end);
-                       WARN_ON(io_end->flag & EXT4_IO_END_UNWRITTEN);
-                       ext4_put_io_end(io_end);
-                       iocb->private = NULL;
-               }
        }
        if (ret > 0 && !overwrite && ext4_test_inode_state(inode,
                                                EXT4_STATE_DIO_UNWRITTEN)) {

diff --git a/fs/ext4/page-io.c b/fs/ext4/page-io.c
index 090b3498638e7a7282e2c9f1ff7426bc01153e21..f49a87c4fb63e856710070f1378b66498d9df6c6 100644 (file)
--- a/fs/ext4/page-io.c
+++ b/fs/ext4/page-io.c
@@ -139,16 +139,6 @@ static void ext4_release_io_end(ext4_io_end_t *io_end)
        kmem_cache_free(io_end_cachep, io_end);
 }
 
-static void ext4_clear_io_unwritten_flag(ext4_io_end_t *io_end)
-{
-       struct inode *inode = io_end->inode;
-
-       io_end->flag &= ~EXT4_IO_END_UNWRITTEN;
-       /* Wake up anyone waiting on unwritten extent conversion */
-       if (atomic_dec_and_test(&EXT4_I(inode)->i_unwritten))
-               wake_up_all(ext4_ioend_wq(inode));
-}
-
 /*
  * Check a range of space and convert unwritten extents to written. Note that
  * we are protected from truncate touching same part of extent tree by the