From 01c6d7d976aa3582d457948c8c6edef08d6ad986 Mon Sep 17 00:00:00 2001
From: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Date: Mon, 28 Jan 2008 23:58:26 -0500
Subject: [PATCH] --- yaml --- r: 77892 b: refs/heads/master c:
 389d1b083c767a360ec84b27a95da06244becec8 h: refs/heads/master v: v3

---
 [refs]                            |  2 +-
 trunk/fs/buffer.c                 | 44 +++++++++++++++++++++++++++++++
 trunk/include/linux/buffer_head.h |  2 ++
 3 files changed, 47 insertions(+), 1 deletion(-)

diff --git a/[refs] b/[refs]
index 26d6109c0a67..fd3e2b769437 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: bb4f397a1a7f2330cb173233599aa159f5780f58
+refs/heads/master: 389d1b083c767a360ec84b27a95da06244becec8
diff --git a/trunk/fs/buffer.c b/trunk/fs/buffer.c
index 7249e014819e..456c9ab7705b 100644
--- a/trunk/fs/buffer.c
+++ b/trunk/fs/buffer.c
@@ -3213,6 +3213,50 @@ static int buffer_cpu_notify(struct notifier_block *self,
 	return NOTIFY_OK;
 }
 
+/**
+ * bh_uptodate_or_lock: Test whether the buffer is uptodate
+ * @bh: struct buffer_head
+ *
+ * Return true if the buffer is up-to-date and false,
+ * with the buffer locked, if not.
+ */
+int bh_uptodate_or_lock(struct buffer_head *bh)
+{
+	if (!buffer_uptodate(bh)) {
+		lock_buffer(bh);
+		if (!buffer_uptodate(bh))
+			return 0;
+		unlock_buffer(bh);
+	}
+	return 1;
+}
+EXPORT_SYMBOL(bh_uptodate_or_lock);
+
+/**
+ * bh_submit_read: Submit a locked buffer for reading
+ * @bh: struct buffer_head
+ *
+ * Returns zero on success and -EIO on error.
+ */
+int bh_submit_read(struct buffer_head *bh)
+{
+	BUG_ON(!buffer_locked(bh));
+
+	if (buffer_uptodate(bh)) {
+		unlock_buffer(bh);
+		return 0;
+	}
+
+	get_bh(bh);
+	bh->b_end_io = end_buffer_read_sync;
+	submit_bh(READ, bh);
+	wait_on_buffer(bh);
+	if (buffer_uptodate(bh))
+		return 0;
+	return -EIO;
+}
+EXPORT_SYMBOL(bh_submit_read);
+
 void __init buffer_init(void)
 {
 	int nrpages;
diff --git a/trunk/include/linux/buffer_head.h b/trunk/include/linux/buffer_head.h
index da0d83fbadc0..e98801f06dcc 100644
--- a/trunk/include/linux/buffer_head.h
+++ b/trunk/include/linux/buffer_head.h
@@ -192,6 +192,8 @@ int sync_dirty_buffer(struct buffer_head *bh);
 int submit_bh(int, struct buffer_head *);
 void write_boundary_block(struct block_device *bdev,
 			sector_t bblock, unsigned blocksize);
+int bh_uptodate_or_lock(struct buffer_head *bh);
+int bh_submit_read(struct buffer_head *bh);
 
 extern int buffer_heads_over_limit;