direct-io: Handle O_(D)SYNC AIO
Call generic_write_sync() from the deferred I/O completion handler if
O_DSYNC is set for a write request. Also make sure various callers
don't call generic_write_sync if the direct I/O code returns
-EIOCBQUEUED.
Based on an earlier patch from Jan Kara <jack@suse.cz> with updates from
Jeff Moyer <jmoyer@redhat.com> and Darrick J. Wong <darrick.wong@oracle.com>.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/direct-io.c b/fs/direct-io.c
index 8b31b9f..1782023 100644
--- a/fs/direct-io.c
+++ b/fs/direct-io.c
@@ -266,8 +266,18 @@
dio->end_io(dio->iocb, offset, transferred, dio->private);
inode_dio_done(dio->inode);
- if (is_async)
+ if (is_async) {
+ if (dio->rw & WRITE) {
+ int err;
+
+ err = generic_write_sync(dio->iocb->ki_filp, offset,
+ transferred);
+ if (err < 0 && ret > 0)
+ ret = err;
+ }
+
aio_complete(dio->iocb, ret, 0);
+ }
kmem_cache_free(dio_cache, dio);
return ret;
@@ -1183,11 +1193,6 @@
}
/*
- * Will be decremented at I/O completion time.
- */
- atomic_inc(&inode->i_dio_count);
-
- /*
* For file extending writes updating i_size before data
* writeouts complete can expose uninitialized blocks. So
* even for AIO, we need to wait for i/o to complete before
@@ -1195,11 +1200,33 @@
*/
dio->is_async = !is_sync_kiocb(iocb) && !((rw & WRITE) &&
(end > i_size_read(inode)));
-
- retval = 0;
-
dio->inode = inode;
dio->rw = rw;
+
+ /*
+ * For AIO O_(D)SYNC writes we need to defer completions to a workqueue
+ * so that we can call ->fsync.
+ */
+ if (dio->is_async && (rw & WRITE) &&
+ ((iocb->ki_filp->f_flags & O_DSYNC) ||
+ IS_SYNC(iocb->ki_filp->f_mapping->host))) {
+ retval = dio_set_defer_completion(dio);
+ if (retval) {
+ /*
+ * We grab i_mutex only for reads so we don't have
+ * to release it here
+ */
+ kmem_cache_free(dio_cache, dio);
+ goto out;
+ }
+ }
+
+ /*
+ * Will be decremented at I/O completion time.
+ */
+ atomic_inc(&inode->i_dio_count);
+
+ retval = 0;
sdio.blkbits = blkbits;
sdio.blkfactor = i_blkbits - blkbits;
sdio.block_in_file = offset >> blkbits;
