[PATCH] fsync: extract internal code

Pull the guts out of do_fsync() - we can use it elsewhere.

Cc: Hugh Dickins <hugh@veritas.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

fs/buffer.c

@@ -327,31 +327,24 @@ int file_fsync(struct file *filp, struct dentry *dentry, int datasync)
 	return ret;
 }
 
-static long do_fsync(unsigned int fd, int datasync)
+long do_fsync(struct file *file, int datasync)
 {
-	struct file * file;
-	struct address_space *mapping;
-	int ret, err;
-
-	ret = -EBADF;
-	file = fget(fd);
-	if (!file)
-		goto out;
+	int ret;
+	int err;
+	struct address_space *mapping = file->f_mapping;
 
-	ret = -EINVAL;
 	if (!file->f_op || !file->f_op->fsync) {
 		/* Why?  We can still call filemap_fdatawrite */
-		goto out_putf;
+		ret = -EINVAL;
+		goto out;
 	}
 
-	mapping = file->f_mapping;
-
 	current->flags |= PF_SYNCWRITE;
 	ret = filemap_fdatawrite(mapping);
 
 	/*
-	 * We need to protect against concurrent writers,
-	 * which could cause livelocks in fsync_buffers_list
+	 * We need to protect against concurrent writers, which could cause
+	 * livelocks in fsync_buffers_list().
 	 */
 	mutex_lock(&mapping->host->i_mutex);
 	err = file->f_op->fsync(file, file->f_dentry, datasync);
@@ -362,21 +355,31 @@ static long do_fsync(unsigned int fd, int datasync)
 	if (!ret)
 		ret = err;
 	current->flags &= ~PF_SYNCWRITE;
-
-out_putf:
-	fput(file);
 out:
 	return ret;
 }
 
+static long __do_fsync(unsigned int fd, int datasync)
+{
+	struct file *file;
+	int ret = -EBADF;
+
+	file = fget(fd);
+	if (file) {
+		ret = do_fsync(file, datasync);
+		fput(file);
+	}
+	return ret;
+}
+
 asmlinkage long sys_fsync(unsigned int fd)
 {
-	return do_fsync(fd, 0);
+	return __do_fsync(fd, 0);
 }
 
 asmlinkage long sys_fdatasync(unsigned int fd)
 {
-	return do_fsync(fd, 1);
+	return __do_fsync(fd, 1);
 }
 
 /*

include/linux/fs.h

@@ -1478,6 +1478,7 @@ extern int wait_on_page_writeback_range(struct address_space *mapping,
 extern int __filemap_fdatawrite_range(struct address_space *mapping,
 				loff_t start, loff_t end, int sync_mode);
 
+extern long do_fsync(struct file *file, int datasync);
 extern void sync_supers(void);
 extern void sync_filesystems(int wait);
 extern void emergency_sync(void);