From 23488aedfcf7608c33e53c4721fd515d55eaaecd Mon Sep 17 00:00:00 2001
From: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Date: Wed, 18 Jan 2006 17:43:00 -0800
Subject: [PATCH] --- yaml --- r: 18932 b: refs/heads/master c:
 4833aff757b747b51b878a13f3a6e2b1a2abb619 h: refs/heads/master v: v3

---
 [refs]                           |  2 +-
 trunk/arch/um/drivers/ubd_kern.c | 28 +++++++++++++++-------------
 2 files changed, 16 insertions(+), 14 deletions(-)

diff --git a/[refs] b/[refs]
index a1ec4556003d..b5d7be776e7a 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: ce2d2aedcc3ca582fed90f44970e8b3e4f006a7d
+refs/heads/master: 4833aff757b747b51b878a13f3a6e2b1a2abb619
diff --git a/trunk/arch/um/drivers/ubd_kern.c b/trunk/arch/um/drivers/ubd_kern.c
index 7696f8d2d89c..c171d0aa5e9d 100644
--- a/trunk/arch/um/drivers/ubd_kern.c
+++ b/trunk/arch/um/drivers/ubd_kern.c
@@ -1103,31 +1103,33 @@ static int ubd_ioctl(struct inode * inode, struct file * file,
 	return(-EINVAL);
 }
 
-static int same_backing_files(char *from_cmdline, char *from_cow, char *cow)
+static int path_requires_switch(char *from_cmdline, char *from_cow, char *cow)
 {
 	struct uml_stat buf1, buf2;
 	int err;
 
-	if(from_cmdline == NULL) return(1);
-	if(!strcmp(from_cmdline, from_cow)) return(1);
+	if(from_cmdline == NULL)
+		return 0;
+	if(!strcmp(from_cmdline, from_cow))
+		return 0;
 
 	err = os_stat_file(from_cmdline, &buf1);
 	if(err < 0){
 		printk("Couldn't stat '%s', err = %d\n", from_cmdline, -err);
-		return(1);
+		return 0;
 	}
 	err = os_stat_file(from_cow, &buf2);
 	if(err < 0){
 		printk("Couldn't stat '%s', err = %d\n", from_cow, -err);
-		return(1);
+		return 1;
 	}
 	if((buf1.ust_dev == buf2.ust_dev) && (buf1.ust_ino == buf2.ust_ino))
-		return(1);
+		return 0;
 
 	printk("Backing file mismatch - \"%s\" requested,\n"
 	       "\"%s\" specified in COW header of \"%s\"\n",
 	       from_cmdline, from_cow, cow);
-	return(0);
+	return 1;
 }
 
 static int backing_file_mismatch(char *file, __u64 size, time_t mtime)
@@ -1189,7 +1191,7 @@ int open_ubd_file(char *file, struct openflags *openflags,
 	unsigned long long size;
 	__u32 version, align;
 	char *backing_file;
-	int fd, err, sectorsize, same, mode = 0644;
+	int fd, err, sectorsize, asked_switch, mode = 0644;
 
 	fd = os_open_file(file, *openflags, mode);
 	if(fd < 0){
@@ -1209,6 +1211,7 @@ int open_ubd_file(char *file, struct openflags *openflags,
 		goto out_close;
 	}
 
+	/* Succesful return case! */
 	if(backing_file_out == NULL) return(fd);
 
 	err = read_cow_header(file_reader, &fd, &version, &backing_file, &mtime,
@@ -1220,17 +1223,16 @@ int open_ubd_file(char *file, struct openflags *openflags,
 	}
 	if(err) return(fd);
 
-	if(backing_file_out == NULL) return(fd);
-
-	same = same_backing_files(*backing_file_out, backing_file, file);
+	asked_switch = path_requires_switch(*backing_file_out, backing_file, file);
 
-	if(!same && !backing_file_mismatch(*backing_file_out, size, mtime)){
+	/* Allow switching only if no mismatch. */
+	if (asked_switch && !backing_file_mismatch(*backing_file_out, size, mtime)) {
 		printk("Switching backing file to '%s'\n", *backing_file_out);
 		err = write_cow_header(file, fd, *backing_file_out,
 				       sectorsize, align, &size);
 		if(err){
 			printk("Switch failed, errno = %d\n", -err);
-			return(err);
+			goto out_close;
 		}
 	}
 	else {