After some thoughts I decided to fix this bug.
It appears that you need to use O_LARGEFILE flag to filp_open() if the caller can handle 64 bit addressing in the file. And since cloop uses 64bit loff_t addresses it should be able to do it.
Attached is a patch addressing this problem. I also made it gracefully handle inability to open a file - unregister major number and all disks.
As a bonus, I've added some handling of LOOP_GET/SET_STATUS ioctl calls too. This way losetup will be able to show which file keeps a cloop device and as a result the cloop module itself.
Hope you like it, Igor
--- modules/cloop/compressed_loop.c.orig 2005-03-04 21:17:23.000000000 -0500
+++ modules/cloop/compressed_loop.c 2005-03-04 21:04:46.000000000 -0500
@@ -120,6 +120,7 @@
struct file *backing_file; /* associated file */
struct inode *backing_inode; /* for bmap */
+ char backing_file_name[LO_NAME_SIZE];
unsigned int underlying_blksize;
int refcnt;
@@ -448,6 +449,8 @@
}
clo->backing_file = file;
+ memcpy(clo->backing_file_name, filename, LO_NAME_SIZE);
+ clo->backing_file_name[LO_NAME_SIZE-1] = 0;
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,5,0)
clo->dev = dev;
#endif
@@ -625,6 +628,7 @@
error_release:
if(bbuf) vfree(bbuf);
clo->backing_file=NULL;
+ memset(clo->backing_file_name, 0, LO_NAME_SIZE);
return error;
}
@@ -663,6 +667,7 @@
else { filp_close(initial_file,0); initial_file=NULL; }
clo->backing_file = NULL;
clo->backing_inode = NULL;
+ memset(clo->backing_file_name, 0, LO_NAME_SIZE);
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,5,0)
cloop_sizes[cloop_num] = 0;
cloop_blksizes[cloop_num] = 0;
@@ -678,6 +683,7 @@
{
struct cloop_device *clo;
int cloop_num, err=0;
+ struct loop_info info;
if (!inode) return -EINVAL;
if (MAJOR(inode->i_rdev) != MAJOR_NR) {
@@ -700,8 +706,26 @@
err = clo_clr_fd(cloop_num, inode->i_bdev);
break;
case LOOP_SET_STATUS:
+ if(copy_from_user(&info,(struct loop_info __user *)arg,sizeof(info)))
+ err = -EFAULT;
+ else if (clo->backing_file) {
+ memcpy(clo->backing_file_name, info.lo_name, LO_NAME_SIZE);
+ clo->backing_file_name[LO_NAME_SIZE-1] = 0;
+ } else
+ err = -ENXIO;
+ break;
case LOOP_GET_STATUS:
- err=0; break;
+ memset(&info, 0, sizeof(info));
+ if (clo->backing_file) {
+ memcpy(info.lo_name, clo->backing_file_name, LO_NAME_SIZE);
+ info.lo_number = cloop_num;
+ info.lo_inode = clo->backing_inode->i_ino;
+ info.lo_device = new_encode_dev(clo->backing_inode->i_rdev);
+ if(copy_to_user((struct loop_info __user *)arg,&info,sizeof(info)))
+ err = -EFAULT;
+ } else
+ err = -ENXIO;
+ break;
default:
err = -EINVAL;
}
@@ -832,13 +856,16 @@
if(file) /* global file name for first cloop-Device is a module option string. */
{
- initial_file=filp_open(file,0x00,0x00);
- if(initial_file==NULL||IS_ERR(initial_file))
+ initial_file=filp_open(file, O_RDONLY | O_LARGEFILE, 0);
+ if(initial_file==NULL||IS_ERR(initial_file))
{
printk(KERN_ERR
- "%s: Unable to get file %s for cloop device\n",
- cloop_name, file);
- return -EINVAL;
+ "%s: Unable to get file %s for cloop device (%ld)\n",
+ cloop_name, file, PTR_ERR(initial_file));
+ error = -EINVAL;
+ initial_file = NULL;
+ i=max_cloop;
+ goto out_mem;
}
error=clo_set_file(0,initial_file,file);
if(error) { i=max_cloop; goto out_mem; }
@@ -857,6 +884,7 @@
/* error_filp_close: */
if(initial_file) filp_close(initial_file,0); initial_file=NULL;
cloop_dev[0].backing_file=NULL;
+ memset(cloop_dev[0].backing_file_name, 0, LO_NAME_SIZE);
return error;
}
