fix mknod

PATCH In review Johannes Stezenbach 3 participants 6 messages Jan 22, 2007 – Jan 26, 2007 User-mode Linux (UML)

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Johannes Stezenbach

author

2007-01-22 20:13 UTC #0 lore raw

PATCH 1/1 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 <[email protected]>

fs/hostfs/hostfs.h +11 -1

diff -rup linux-2.6.19.orig/fs/hostfs/hostfs.h linux-2.6.19/fs/hostfs/hostfs.h
@@ -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);

fs/hostfs/hostfs_kern.c +4 -1

diff -rup linux-2.6.19.orig/fs/hostfs/hostfs_kern.c linux-2.6.19/fs/hostfs/hostfs_kern.c
@@ -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;

fs/hostfs/hostfs_user.c +1 -1

diff -rup linux-2.6.19.orig/fs/hostfs/hostfs_user.c linux-2.6.19/fs/hostfs/hostfs_user.c
@@ -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;

Blaisorblade

2007-01-23 08:02 UTC #1 lore raw

Quoted 7 lines · Johannes Stezenbach

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

Hmpf. Still having this bug on hostfs is quite bad. Thanks for reporting.

It should be hostfs_user.c to take major and minor and to combine them correctly - it can use libc's macros.

Quoted 73 lines

Signed-off-by Johannes Stezenbach <[email protected]>
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);
fs/hostfs/hostfs.h +3 -1
-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) +{
fs/hostfs/hostfs.h +7 -0
+	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
fs/hostfs/hostfs_kern.c +4 -1
 	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)
fs/hostfs/hostfs_user.c +1 -2
 	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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Signature · 5 lines

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Paolo Giarrusso, aka Blaisorblade
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Johannes Stezenbach

author

2007-01-23 13:17 UTC #2 lore raw

Quoted 10 lines · Blaisorblade

Quoted 4 lines · Johannes Stezenbach
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.
Hmpf. Still having this bug on hostfs is quite bad. Thanks for reporting.
It should be hostfs_user.c to take major and minor and to combine them correctly - it can use libc's macros.

Right, below is a better patch.

Thanks,
Johannes

---
Fix UML hostfs mknod(): userspace has differernt dev_t size and encoding than kernel, so extract major/minor and reencode using glibc makedev() macro.

Signed-off-by Johannes Stezenbach <[email protected]>

fs/hostfs/hostfs.h +1 -1

diff -rup linux-2.6.19.orig/fs/hostfs/hostfs.h linux-2.6.19/fs/hostfs/hostfs.h
@@ -76,7 +76,7 @@ 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);
+extern int do_mknod(const char *file, int mode, unsigned int major, unsigned int minor);
 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);

fs/hostfs/hostfs_kern.c +1 -1

diff -rup linux-2.6.19.orig/fs/hostfs/hostfs_kern.c linux-2.6.19/fs/hostfs/hostfs_kern.c
@@ -755,7 +755,7 @@ int hostfs_mknod(struct inode *dir, stru
 		goto out_put;
 
 	init_special_inode(inode, mode, dev);
-	err = do_mknod(name, mode, dev);
+	err = do_mknod(name, mode, MAJOR(dev), MINOR(dev));
 	if(err)
 		goto out_free;

fs/hostfs/hostfs_user.c +2 -2

diff -rup linux-2.6.19.orig/fs/hostfs/hostfs_user.c linux-2.6.19/fs/hostfs/hostfs_user.c
@@ -295,11 +295,11 @@ 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 int major, unsigned int minor)
 {
 	int err;
 
-	err = mknod(file, mode, dev);
+	err = mknod(file, mode, makedev(major, minor));
 	if(err) return(-errno);
 	return(0);
 }

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Blaisorblade

Acked-by

2007-01-23 22:33 UTC #3 lore raw

Quoted 7 lines · Johannes Stezenbach

Quoted 6 lines · Blaisorblade
Quoted 3 lines · Johannes Stezenbach
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.
Hmpf. Still having this bug on hostfs is quite bad. Thanks for reporting.

I've now seen - we never fixed this one, we fixed the analogous problem on 'ls' output and friends (in init_inode, which is used in many places).

Quoted 4 lines

Quoted 2 lines
It should be hostfs_user.c to take major and minor and to combine them correctly - it can use libc's macros.
Right, below is a better patch.

Exactly what I meant, thanks!
I'd say:

Acked-by Paolo 'Blaisorblade' Giarrusso <[email protected]>

This can go to 2.6.20, and possibly even to -stable (after either me or Jeff tests it once).

Quoted 55 lines

---
Fix UML hostfs mknod(): userspace has differernt dev_t size and encoding than kernel, so extract major/minor and reencode using glibc makedev() macro.
Signed-off-by Johannes Stezenbach <[email protected]>
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 2007-01-23 14:11:03.000000000 +0100 @@
-76,7 +76,7 @@ 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);
(quoted diff) +1 -1
-extern int do_mknod(const char *file, int mode, int dev);
+extern int do_mknod(const char *file, int mode, unsigned int major,
unsigned int minor);
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 2007-01-23
14:11:20.000000000 +0100 @@ -755,7 +755,7 @@ int hostfs_mknod(struct inode *dir, stru
fs/hostfs/hostfs_kern.c +1 -1
 		goto out_put;
 
 	init_special_inode(inode, mode, dev);
-	err = do_mknod(name, mode, dev);
+	err = do_mknod(name, mode, MAJOR(dev), MINOR(dev));
 	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 2007-01-23
14:11:39.000000000 +0100 @@ -295,11 +295,11 @@ int do_rmdir(const char *file)
fs/hostfs/hostfs_user.c +1 -1
 	return(0);
 }
 
-int do_mknod(const char *file, int mode, int dev)
+int do_mknod(const char *file, int mode, unsigned int major, unsigned int
minor) {
fs/hostfs/hostfs_user.c +1 -1
 	int err;
 
-	err = mknod(file, mode, dev);
+	err = mknod(file, mode, makedev(major, minor));
 	if(err) return(-errno);
 	return(0);
 }

Signature · 5 lines

Inform me of my mistakes, so I can add them to my list!
Paolo Giarrusso, aka Blaisorblade
http://www.user-mode-linux.org/~blaisorblade
Chiacchiera con i tuoi amici in tempo reale! 
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Andrew Morton

2007-01-25 04:32 UTC #4 lore raw

Quoted 15 lines · On Tue, 23 Jan 2007 23:33:29 +0100 Blaisorblade <[email protected]> wrote:

Quoted 7 lines · Johannes Stezenbach
Quoted 6 lines · Blaisorblade
Quoted 3 lines · Johannes Stezenbach
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.
Hmpf. Still having this bug on hostfs is quite bad. Thanks for reporting.
I've now seen - we never fixed this one, we fixed the analogous problem on 'ls' output and friends (in init_inode, which is used in many places).
Quoted 3 lines
Quoted 2 lines
It should be hostfs_user.c to take major and minor and to combine them correctly - it can use libc's macros.

Quoted 7 lines

Quoted 1 line
Right, below is a better patch.
Exactly what I meant, thanks!
I'd say:
Acked-by Paolo 'Blaisorblade' Giarrusso <[email protected]>
This can go to 2.6.20, and possibly even to -stable (after either me or Jeff tests it once).

So.. did you test it?

Blaisorblade

2007-01-26 18:50 UTC #5 lore raw

Quoted 21 lines · Andrew Morton

On Tue, 23 Jan 2007 23:33:29 +0100
Quoted 18 lines · Blaisorblade
Quoted 8 lines · Johannes Stezenbach
Quoted 7 lines · Blaisorblade
Quoted 3 lines · Johannes Stezenbach
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.
Hmpf. Still having this bug on hostfs is quite bad. Thanks for reporting.
I've now seen - we never fixed this one, we fixed the analogous problem on 'ls' output and friends (in init_inode, which is used in many places).
Quoted 4 lines
Quoted 2 lines
It should be hostfs_user.c to take major and minor and to combine them correctly - it can use libc's macros.
Right, below is a better patch.

Quoted 7 lines

Quoted 5 lines
Exactly what I meant, thanks!
I'd say:
Acked-by Paolo 'Blaisorblade' Giarrusso <[email protected]>
This can go to 2.6.20, and possibly even to -stable (after either me or Jeff tests it once).
So.. did you test it?

Just tested, I could reproduce the bug and verify the fix works, on 2.6.18; and for me it's enough to merge it, considering that little changes happened on hostfs, and because it's well understood with static review that this fix is needed.

It should also be merged in 2.6.16-stable.

Signature · 5 lines

Inform me of my mistakes, so I can add them to my list!
Paolo Giarrusso, aka Blaisorblade
http://www.user-mode-linux.org/~blaisorblade
Chiacchiera con i tuoi amici in tempo reale! 
 http://it.yahoo.com/mail_it/foot/*http://it.messenger.yahoo.com