Function generic_file_direct_write() tries to invalidate pagecache after
O_DIRECT write. Unlike to similar code in dio_complete() this silently
ignores error returned from invalidate_inode_pages2_range().
According to comment this code here because not all filesystems call
dio_complete() or do proper invalidation after O_DIRECT write.
Noticeable case is a blkdev_direct_IO().
This patch calls dio_warn_stale_pagecache() if invalidation fails.
Also this skips invalidation for async writes (written == -EIOCBQUEUED).
Async write should call dio_complete() later, when write completes.
Signed-off-by: Konstantin Khlebnikov <khlebnikov@xxxxxxxxxxxxxx>
---
mm/filemap.c | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)
diff --git a/mm/filemap.c b/mm/filemap.c
index 92abf5f348a9..1fa8d587ef78 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -3222,11 +3222,15 @@ generic_file_direct_write(struct kiocb *iocb, struct iov_iter *from)
* Most of the time we do not need this since dio_complete() will do
* the invalidation for us. However there are some file systems that
* do not end up with dio_complete() being called, so let's not break
- * them by removing it completely
+ * them by removing it completely.
+ *
+ * Noticeable case is a blkdev_direct_IO().
+ *
+ * Skip invalidation for async writes or if mapping has no pages.
*/
- if (mapping->nrpages)
- invalidate_inode_pages2_range(mapping,
- pos >> PAGE_SHIFT, end);
+ if (written > 0 && mapping->nrpages &&
+ invalidate_inode_pages2_range(mapping, pos >> PAGE_SHIFT, end))
+ dio_warn_stale_pagecache(file);
if (written > 0) {
pos += written;
