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Subject[PATCH] [UML] fix mknod
Hi,

I was playing with user-mode Linux and found that mknod creates
devices node in hostfs with wrong major/minor numbers.
The patch below fixes it for me.

Johannes


---
mknod() is broken on UML because userspace has differernt
dev_t size and encoding than kernel.

Signed-off-by: Johannes Stezenbach <js@linuxtv.org>


diff -rup linux-2.6.19.orig/fs/hostfs/hostfs.h linux-2.6.19/fs/hostfs/hostfs.h
--- linux-2.6.19.orig/fs/hostfs/hostfs.h 2006-11-29 22:57:37.000000000 +0100
+++ linux-2.6.19/fs/hostfs/hostfs.h 2007-01-22 20:53:23.000000000 +0100
@@ -76,7 +76,17 @@ extern int make_symlink(const char *from
extern int unlink_file(const char *file);
extern int do_mkdir(const char *file, int mode);
extern int do_rmdir(const char *file);
-extern int do_mknod(const char *file, int mode, int dev);
+
+/* gnu_dev_makedev from glibc's sys/sysmacros.h */
+static inline unsigned long long makedev(unsigned int major, unsigned int minor)
+{
+ return ((minor & 0xff) | ((major & 0xfff) << 8)
+ | (((unsigned long long int) (minor & ~0xff)) << 12)
+ | (((unsigned long long int) (major & ~0xfff)) << 32));
+
+}
+
+extern int do_mknod(const char *file, int mode, unsigned long long dev);
extern int link_file(const char *from, const char *to);
extern int do_readlink(char *file, char *buf, int size);
extern int rename_file(char *from, char *to);
diff -rup linux-2.6.19.orig/fs/hostfs/hostfs_kern.c linux-2.6.19/fs/hostfs/hostfs_kern.c
--- linux-2.6.19.orig/fs/hostfs/hostfs_kern.c 2006-11-29 22:57:37.000000000 +0100
+++ linux-2.6.19/fs/hostfs/hostfs_kern.c 2007-01-22 20:57:58.000000000 +0100
@@ -740,6 +740,7 @@ int hostfs_mknod(struct inode *dir, stru
struct inode *inode;
char *name;
int err = -ENOMEM;
+ unsigned long long udev;

inode = iget(dir->i_sb, 0);
if(inode == NULL)
@@ -755,7 +756,9 @@ int hostfs_mknod(struct inode *dir, stru
goto out_put;

init_special_inode(inode, mode, dev);
- err = do_mknod(name, mode, dev);
+ /* userspace has different dev_t encoding than kernel... */
+ udev = makedev(MAJOR(dev), MINOR(dev));
+ err = do_mknod(name, mode, udev);
if(err)
goto out_free;

diff -rup linux-2.6.19.orig/fs/hostfs/hostfs_user.c linux-2.6.19/fs/hostfs/hostfs_user.c
--- linux-2.6.19.orig/fs/hostfs/hostfs_user.c 2006-11-29 22:57:37.000000000 +0100
+++ linux-2.6.19/fs/hostfs/hostfs_user.c 2007-01-22 20:54:37.000000000 +0100
@@ -295,7 +295,7 @@ int do_rmdir(const char *file)
return(0);
}

-int do_mknod(const char *file, int mode, int dev)
+int do_mknod(const char *file, int mode, unsigned long long dev)
{
int err;

-
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