1 files changed, 19 insertions, 10 deletions

diff --git a/fs/direct-io.c b/fs/direct-io.c
index 848044af7e16..235ed8d1f11e 100644
--- a/fs/direct-io.c
+++ b/fs/direct-io.c
@@ -129,6 +129,7 @@ struct dio {
 	/* AIO related stuff */
 	struct kiocb *iocb;		/* kiocb */
 	int is_async;			/* is IO async ? */
+	int io_error;			/* IO error in completion path */
 	ssize_t result;                 /* IO result */
 };
 
@@ -250,6 +251,10 @@ static void finished_one_bio(struct dio *dio)
 			    ((offset + transferred) > dio->i_size))
 				transferred = dio->i_size - offset;
 
+			/* check for error in completion path */
+			if (dio->io_error)
+				transferred = dio->io_error;
+
 			dio_complete(dio, offset, transferred);
 
 			/* Complete AIO later if falling back to buffered i/o */
@@ -406,7 +411,7 @@ static int dio_bio_complete(struct dio *dio, struct bio *bio)
 	int page_no;
 
 	if (!uptodate)
-		dio->result = -EIO;
+		dio->io_error = -EIO;
 
 	if (dio->is_async && dio->rw == READ) {
 		bio_check_pages_dirty(bio);	/* transfers ownership */
@@ -971,6 +976,7 @@ direct_io_worker(int rw, struct kiocb *iocb, struct inode *inode,
 	dio->next_block_for_io = -1;
 
 	dio->page_errors = 0;
+	dio->io_error = 0;
 	dio->result = 0;
 	dio->iocb = iocb;
 	dio->i_size = i_size_read(inode);
@@ -1155,15 +1161,16 @@ direct_io_worker(int rw, struct kiocb *iocb, struct inode *inode,
  * For writes, i_mutex is not held on entry; it is never taken.
  *
  * DIO_LOCKING (simple locking for regular files)
- * For writes we are called under i_mutex and return with i_mutex held, even though
- * it is internally dropped.
+ * For writes we are called under i_mutex and return with i_mutex held, even
+ * though it is internally dropped.
  * For reads, i_mutex is not held on entry, but it is taken and dropped before
  * returning.
  *
  * DIO_OWN_LOCKING (filesystem provides synchronisation and handling of
  *	uninitialised data, allowing parallel direct readers and writers)
  * For writes we are called without i_mutex, return without it, never touch it.
- * For reads, i_mutex is held on entry and will be released before returning.
+ * For reads we are called under i_mutex and return with i_mutex held, even
+ * though it may be internally dropped.
  *
  * Additional i_alloc_sem locking requirements described inline below.
  */
@@ -1182,7 +1189,8 @@ __blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode,
 	ssize_t retval = -EINVAL;
 	loff_t end = offset;
 	struct dio *dio;
-	int reader_with_isem = (rw == READ && dio_lock_type == DIO_OWN_LOCKING);
+	int release_i_mutex = 0;
+	int acquire_i_mutex = 0;
 
 	if (rw & WRITE)
 		current->flags |= PF_SYNCWRITE;
@@ -1225,7 +1233,6 @@ __blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode,
 	 *	writers need to grab i_alloc_sem only (i_mutex is already held)
 	 * For regular files using DIO_OWN_LOCKING,
 	 *	neither readers nor writers take any locks here
-	 *	(i_mutex is already held and release for writers here)
 	 */
 	dio->lock_type = dio_lock_type;
 	if (dio_lock_type != DIO_NO_LOCKING) {
@@ -1236,7 +1243,7 @@ __blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode,
 			mapping = iocb->ki_filp->f_mapping;
 			if (dio_lock_type != DIO_OWN_LOCKING) {
 				mutex_lock(&inode->i_mutex);
-				reader_with_isem = 1;
+				release_i_mutex = 1;
 			}
 
 			retval = filemap_write_and_wait_range(mapping, offset,
@@ -1248,7 +1255,7 @@ __blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode,
 
 			if (dio_lock_type == DIO_OWN_LOCKING) {
 				mutex_unlock(&inode->i_mutex);
-				reader_with_isem = 0;
+				acquire_i_mutex = 1;
 			}
 		}
 
@@ -1269,11 +1276,13 @@ __blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode,
 				nr_segs, blkbits, get_blocks, end_io, dio);
 
 	if (rw == READ && dio_lock_type == DIO_LOCKING)
-		reader_with_isem = 0;
+		release_i_mutex = 0;
 
 out:
-	if (reader_with_isem)
+	if (release_i_mutex)
 		mutex_unlock(&inode->i_mutex);
+	else if (acquire_i_mutex)
+		mutex_lock(&inode->i_mutex);
 	if (rw & WRITE)
 		current->flags &= ~PF_SYNCWRITE;
 	return retval;