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path: root/arch/um/drivers/ubd_kern.c
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Diffstat (limited to 'arch/um/drivers/ubd_kern.c')
-rw-r--r--arch/um/drivers/ubd_kern.c28
1 files changed, 15 insertions, 13 deletions
diff --git a/arch/um/drivers/ubd_kern.c b/arch/um/drivers/ubd_kern.c
index 7696f8d2d89..c171d0aa5e9 100644
--- a/arch/um/drivers/ubd_kern.c
+++ b/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 {