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-rw-r--r--fs/direct-io.c44
1 files changed, 28 insertions, 16 deletions
diff --git a/fs/direct-io.c b/fs/direct-io.c
index d2bc339cb1e9..3aafb3343a65 100644
--- a/fs/direct-io.c
+++ b/fs/direct-io.c
@@ -45,6 +45,12 @@
#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
* is determined on a per-invocation basis. When talking to the filesystem
@@ -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);
}
}
}
@@ -866,7 +877,8 @@ out:
*/
if (sdio->boundary) {
ret = dio_send_cur_page(dio, sdio, map_bh);
- dio_bio_submit(dio, sdio);
+ if (sdio->bio)
+ dio_bio_submit(dio, sdio);
put_page(sdio->cur_page);
sdio->cur_page = NULL;
}
@@ -1140,7 +1152,7 @@ do_blockdev_direct_IO(struct kiocb *iocb, struct inode *inode,
get_block_t get_block, dio_iodone_t end_io,
dio_submit_t submit_io, int flags)
{
- unsigned i_blkbits = ACCESS_ONCE(inode->i_blkbits);
+ unsigned i_blkbits = READ_ONCE(inode->i_blkbits);
unsigned blkbits = i_blkbits;
unsigned blocksize_mask = (1 << blkbits) - 1;
ssize_t retval = -EINVAL;
@@ -1359,7 +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);