Merge branch 'sched/core' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip into trace/tip/tracing/core-4

1 files changed, 12 insertions, 5 deletions

diff --git a/fs/block_dev.c b/fs/block_dev.c
index 2a6d0193f139..6dcee88c2e5d 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -406,16 +406,23 @@ static loff_t block_llseek(struct file *file, loff_t offset, int origin)
  
 int blkdev_fsync(struct file *filp, struct dentry *dentry, int datasync)
 {
-        struct block_device *bdev = I_BDEV(filp->f_mapping->host);
+        struct inode *bd_inode = filp->f_mapping->host;
+        struct block_device *bdev = I_BDEV(bd_inode);
         int error;
 
-        error = sync_blockdev(bdev);
-        if (error)
-                return error;
-        
+        /*
+         * There is no need to serialise calls to blkdev_issue_flush with
+         * i_mutex and doing so causes performance issues with concurrent
+         * O_SYNC writers to a block device.
+         */
+        mutex_unlock(&bd_inode->i_mutex);
+
         error = blkdev_issue_flush(bdev, NULL);
         if (error == -EOPNOTSUPP)
                 error = 0;
+
+        mutex_lock(&bd_inode->i_mutex);
+
         return error;
 }
 EXPORT_SYMBOL(blkdev_fsync);