From: Dave Kleikamp <dave.kleikamp@oracle.com>
Date: Wed, 11 Jan 2012 21:25:26 +0000 (-0600)
Subject: dio: add dio_lock_and_flush() helper
X-Git-Tag: v2.6.39-400.9.0~594^2~12
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=17a7d5edf5c6efe5dfe4c93c3ed070ffe981722b;p=users%2Fjedix%2Flinux-maple.git

dio: add dio_lock_and_flush() helper

This creates a helper function which performs locking based on DIO_LOCKING
and flushes dirty pages.  This will be called by another entry point
like __blockdev_direct_IO() in an upcoming patch.

Signed-off-by: Zach Brown <zach.brown@oracle.com>
Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com>
---

diff --git a/fs/direct-io.c b/fs/direct-io.c
index 9462ed92371e..ba4063e88fe9 100644
--- a/fs/direct-io.c
+++ b/fs/direct-io.c
@@ -1118,6 +1118,35 @@ static void sdio_init(struct dio_submit *sdio, struct inode *inode,
 		sdio->pages_in_io = 2;
 }
 
+static int dio_lock_and_flush(struct dio *dio, loff_t offset, loff_t end)
+{
+	struct inode *inode = dio->inode;
+	int ret;
+
+	if (dio->flags & DIO_LOCKING) {
+		/* watch out for a 0 len io from a tricksy fs */
+		if (dio->rw == READ && end > offset) {
+
+			/* will be released by do_blockdev_direct_IO */
+			mutex_lock(&inode->i_mutex);
+
+			ret = filemap_write_and_wait_range(inode->i_mapping,
+							      offset, end - 1);
+			if (ret) {
+				mutex_unlock(&inode->i_mutex);
+				return ret;
+			}
+		}
+
+		/*
+		 * Will be released at I/O completion, possibly in a
+		 * different thread.
+		 */
+		down_read_non_owner(&inode->i_alloc_sem);
+	}
+	return 0;
+}
+
 /*
  * This is a library function for use by filesystem drivers.
  *
@@ -1180,33 +1209,12 @@ do_blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode,
 	if (!dio)
 		goto out;
 
-	if (dio->flags & DIO_LOCKING) {
-		/* watch out for a 0 len io from a tricksy fs */
-		if (rw == READ && end > offset) {
-			struct address_space *mapping =
-					iocb->ki_filp->f_mapping;
-
-			/* will be released by direct_io_worker */
-			mutex_lock(&inode->i_mutex);
-
-			retval = filemap_write_and_wait_range(mapping, offset,
-							      end - 1);
-			if (retval) {
-				mutex_unlock(&inode->i_mutex);
-				kmem_cache_free(dio_cache, dio);
-				goto out;
-			}
-		}
-
-		/*
-		 * Will be released at I/O completion, possibly in a
-		 * different thread.
-		 */
-		down_read_non_owner(&inode->i_alloc_sem);
+	retval = dio_lock_and_flush(dio, offset, end);
+	if (retval) {	
+		kmem_cache_free(dio_cache, dio);
+		goto out;
 	}
 
-	retval = 0;
-
 	sdio_init(&sdio, inode, offset, blkbits, get_block, submit_io);
 
 	for (seg = 0; seg < nr_segs; seg++) {