Merge tag 'for-linus-4.14c-rc7-tag' of git://git.kernel.org/pub/scm/linux/kernel...

[sfrench/cifs-2.6.git] / fs / direct-io.c

diff --git a/fs/direct-io.c b/fs/direct-io.c
index 96415c65bbdc102f6a5dff696231e944d4fdccdb..b53e66d9abd7030f6b05a6dac4847928c24bf1a0 100644 (file)
--- a/fs/direct-io.c
+++ b/fs/direct-io.c
@@ -44,6 +44,12 @@
  */
 #define DIO_PAGES      64
 
+/*
+ * Flags for dio_complete()
+ */
+#define DIO_COMPLETE_ASYNC             0x01    /* This is async IO */
+#define DIO_COMPLETE_INVALIDATE                0x02    /* Can invalidate pages */
+
 /*
  * This code generally works in units of "dio_blocks".  A dio_block is
  * somewhere between the hard sector size and the filesystem block size.  it
@@ -225,7 +231,7 @@ static inline struct page *dio_get_page(struct dio *dio,
  * filesystems can use it to hold additional state between get_block calls and
  * dio_complete.
  */
-static ssize_t dio_complete(struct dio *dio, ssize_t ret, bool is_async)
+static ssize_t dio_complete(struct dio *dio, ssize_t ret, unsigned int flags)
 {
        loff_t offset = dio->iocb->ki_pos;
        ssize_t transferred = 0;
@@ -259,14 +265,27 @@ static ssize_t dio_complete(struct dio *dio, ssize_t ret, bool is_async)
        if (ret == 0)
                ret = transferred;
 
+       if (dio->end_io) {
+               // XXX: ki_pos??
+               err = dio->end_io(dio->iocb, offset, ret, dio->private);
+               if (err)
+                       ret = err;
+       }
+
        /*
         * Try again to invalidate clean pages which might have been cached by
         * non-direct readahead, or faulted in by get_user_pages() if the source
         * of the write was an mmap'ed region of the file we're writing.  Either
         * one is a pretty crazy thing to do, so we don't support it 100%.  If
         * this invalidation fails, tough, the write still worked...
+        *
+        * And this page cache invalidation has to be after dio->end_io(), as
+        * some filesystems convert unwritten extents to real allocations in
+        * end_io() when necessary, otherwise a racing buffer read would cache
+        * zeros from unwritten extents.
         */
-       if (ret > 0 && dio->op == REQ_OP_WRITE &&
+       if (flags & DIO_COMPLETE_INVALIDATE &&
+           ret > 0 && dio->op == REQ_OP_WRITE &&
            dio->inode->i_mapping->nrpages) {
                err = invalidate_inode_pages2_range(dio->inode->i_mapping,
                                        offset >> PAGE_SHIFT,
@@ -274,18 +293,10 @@ static ssize_t dio_complete(struct dio *dio, ssize_t ret, bool is_async)
                WARN_ON_ONCE(err);
        }
 
-       if (dio->end_io) {
-
-               // XXX: ki_pos??
-               err = dio->end_io(dio->iocb, offset, ret, dio->private);
-               if (err)
-                       ret = err;
-       }
-
        if (!(dio->flags & DIO_SKIP_DIO_COUNT))
                inode_dio_end(dio->inode);
 
-       if (is_async) {
+       if (flags & DIO_COMPLETE_ASYNC) {
                /*
                 * generic_write_sync expects ki_pos to have been updated
                 * already, but the submission path only does this for
@@ -306,7 +317,7 @@ static void dio_aio_complete_work(struct work_struct *work)
 {
        struct dio *dio = container_of(work, struct dio, complete_work);
 
-       dio_complete(dio, 0, true);
+       dio_complete(dio, 0, DIO_COMPLETE_ASYNC | DIO_COMPLETE_INVALIDATE);
 }
 
 static blk_status_t dio_bio_complete(struct dio *dio, struct bio *bio);
@@ -348,7 +359,7 @@ static void dio_bio_end_aio(struct bio *bio)
                        queue_work(dio->inode->i_sb->s_dio_done_wq,
                                   &dio->complete_work);
                } else {
-                       dio_complete(dio, 0, true);
+                       dio_complete(dio, 0, DIO_COMPLETE_ASYNC);
                }
        }
 }
@@ -1360,7 +1371,7 @@ do_blockdev_direct_IO(struct kiocb *iocb, struct inode *inode,
                dio_await_completion(dio);
 
        if (drop_refcount(dio) == 0) {
-               retval = dio_complete(dio, retval, false);
+               retval = dio_complete(dio, retval, DIO_COMPLETE_INVALIDATE);
        } else
                BUG_ON(retval != -EIOCBQUEUED);