diff options
| -rw-r--r-- | arch/um/drivers/ubd_kern.c | 28 |
1 files changed, 15 insertions, 13 deletions
diff --git a/arch/um/drivers/ubd_kern.c b/arch/um/drivers/ubd_kern.c index 7696f8d..c171d0a 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 { |
