Messages in this thread |  | | Date | Mon, 14 May 2001 20:09:45 +0200 (MET DST) | From | Andries.Brouwer@cwi ... | Subject | Re: Minor numbers |
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>> The exercise is essentially the patch that I sent last month or so.
> mknod takes a 32bit input > the stat64 padding only has room for 32bits
Hmm. You make me search for this old patch. Since Linus' reaction was not exactly positive I left the topic again, but there must be a copy somewhere..
Aha, found it. Mail from March 24.
================================================================== ... - For stat all is fine already since we got stat64. - For mknod a little work is required. - The state of affairs with loopinfo is sad today (the fact that kernel and glibc use dev_t of different size causes problems) but all will be well with 64-bit dev_t. ... (iii) mknod: Then there is the prototype of mknod. I changed it for all filesystems to
diff -r linux-2.4.2/linux/fs/ext2/namei.c linux-2.4.2kdevt/linux/fs/ext2/namei.c 387c387,388 < static int ext2_mknod (struct inode * dir, struct dentry *dentry, int mode, int rdev) --- > static int ext2_mknod (struct inode * dir, struct dentry *dentry, int mode, > dev_t rdev)
The system call itself cannot easily be changed to take a larger dev_t, mostly because under old glibc the high order part would be random. So, mknod64, with
diff linux-2.4.2/linux/fs/namei.c linux-2.4.2kdevt/linux/fs/namei.c 1205c1208 < asmlinkage long sys_mknod(const char * filename, int mode, dev_t dev) --- > static long mknod_common(const char * filename, int mode, dev_t dev) 1245a1249,1259 > } > > asmlinkage long sys_mknod64(const char * filename, int mode, > unsigned int ma, unsigned int mi) > { > return mknod_common(filename, mode, ((dev_t) ma << 32) | mi); > } ... ==================================================================
Yes, so mknod is solved by having mknod64. I saw no problems with stat64, but you do. Hmm. I was running a system with 64-bit dev_t when I wrote that letter, so at least for i386 there cannot be any serious problems. Let me see.
=================== include/asm-i386/stat.h ====================== /* This matches struct stat64 in glibc2.1, hence the absolutely * insane amounts of padding around dev_t's. */ struct stat64 { unsigned short st_dev; unsigned char __pad0[10]; ... unsigned short st_rdev; unsigned char __pad3[10]; ... ==================================================================
So, it seems that you are too pessimistic. The present stat64 structure even allows 96-bit dev_t.
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