[PATCH] qnx4fs - kernel 2.4.18pre7

[Anders Larsen]

Thu, Jan 31, 2002 at 22:16:07 +0100
X-Mailer: Balsa 1.2.4

Hi Marcelo,

in the latest release QNX 6.1.0 the boot-sector signature we used to
check for a valid QNX4 partition was removed; it seems they have
extended their partition boot loader and needed the few extra bytes
occupied by the signature.
Other than that, the file-system is unchanged.

The patch below replaces the check for the boot-sector signature by
a check for another signature in the superblock - that one is sure
to stay (until they really change the structure).

The TODO and BUGS files are rather obsolete and can be removed.

I've also updated Configure.help to reflect the fact that QNX6 uses
the same file-system as QNX4 and have removed the EXPERIMENTAL tag
from the read-only part (apart from a complete system hang in 2.4.8/9
there have been no severe bugs reported since 2.4.0, so I think that
move is appropriate now).

Cheers
  Anders (maintainer)

diff -u --recursive linux-2.4.18-pre7/Documentation/Configure.help linux/Documentation/Configure.help
--- linux-2.4.18-pre7/Documentation/Configure.help	Wed Jan 30 21:10:47 2002
+++ linux/Documentation/Configure.help	Wed Jan 30 21:23:58 2002
@@ -14652,10 +14652,12 @@
 
 QNX4 file system support (read only)
 CONFIG_QNX4FS_FS
-  This is the file system used by the operating system QNX 4. Say Y if
-  you intend to mount QNX hard disks or floppies. Unless you say Y to
-  "QNX4FS read-write support" below, you will only be able to read
-  these file systems.
+  This is the file system used by the real-time operating systems
+  QNX 4 and QNX 6 (the latter is also called QNX RTP).
+  Further information is available at <http://www.qnx.com/>.
+  Say Y if you intend to mount QNX hard disks or floppies.
+  Unless you say Y to "QNX4FS read-write support" below, you will
+  only be able to read these file systems.
 
   This file system support is also available as a module ( = code
   which can be inserted in and removed from the running kernel
@@ -14669,6 +14671,9 @@
 QNX4FS write support (DANGEROUS)
 CONFIG_QNX4FS_RW
   Say Y if you want to test write support for QNX4 file systems.
+
+  It's currently broken, so for now:
+  answer N.
 
 Kernel automounter support
 CONFIG_AUTOFS_FS
diff -u --recursive linux-2.4.18-pre7/fs/Config.in linux/fs/Config.in
--- linux-2.4.18-pre7/fs/Config.in	Wed Jan 30 21:10:50 2002
+++ linux/fs/Config.in	Wed Jan 30 21:03:50 2002
@@ -71,7 +71,7 @@
 # breaks.
 dep_bool '/dev/pts file system for Unix98 PTYs' CONFIG_DEVPTS_FS $CONFIG_UNIX98_PTYS
 
-dep_tristate 'QNX4 file system support (read only) (EXPERIMENTAL)' CONFIG_QNX4FS_FS $CONFIG_EXPERIMENTAL
+tristate 'QNX4 file system support (read only)' CONFIG_QNX4FS_FS
 dep_mbool '  QNX4FS write support (DANGEROUS)' CONFIG_QNX4FS_RW $CONFIG_QNX4FS_FS $CONFIG_EXPERIMENTAL
 
 tristate 'ROM file system support' CONFIG_ROMFS_FS
diff -u --recursive linux-2.4.18-pre7/fs/qnx4/BUGS linux/fs/qnx4/BUGS
--- linux-2.4.18-pre7/fs/qnx4/BUGS	Thu Dec 23 02:38:27 1999
+++ linux/fs/qnx4/BUGS	Wed Jan 30 20:55:57 2002
@@ -1,30 +0,0 @@
-Last update: 1999-12-23
-
-- Fragmented files and directories were incorrectly handled.
-  Fixed 1999-12-23, Anders.
-
-- readdir sometimes returned the same dir entry more than once.
-  Fixed 1999-12-13, Anders.
-
-- File names with a length of exactly 16 chars were handled incorrectly.
-  Fixed 1999-12-11, Anders.
-
-- Files in a subdir can't be accessed, I think that the inode information
-  is not correctly copied at some point. Solved 06-06-1998, Richard.
-  
-- At some point the mounted device can't be unmounted. I think that somewhere
-  in the code a buffer is not given free.
-
-- Make the '..' entry work, I give it a great chance that the above bug
-  (not given free) has something to do with this one, after a 'ls -l'
-  the mounted device can't be unmounted and that's where the '..' entry
-  is accessed.
-  Seems to be solved 21-06-1998, Frank.
-
-- File read function not correct, after the first block it goes beserk.
-  Solved 21-06-1998, Frank.
-
-- This fs will not work if not built as a module.
-  Solved 25-06-1998, Frank.
-
-- Write/truncate/delete functions don't update the bitmap.
diff -u --recursive linux-2.4.18-pre7/fs/qnx4/TODO linux/fs/qnx4/TODO
--- linux-2.4.18-pre7/fs/qnx4/TODO	Thu Dec 23 02:38:27 1999
+++ linux/fs/qnx4/TODO	Wed Jan 30 20:57:49 2002
@@ -1,30 +0,0 @@
-Name       : QNX4 TODO list
-Last update: 1999-12-23
-
-    - Writing is still unsupported (it may compile, but it certainly won't
-      bring you any joy).
-
-    - qnx4_checkroot (inode.c), currently there's a look for the '/' in
-      the root direntry, if so then the current mounted device is a qnx4
-      partition. This has to be rewritten with a look for 'QNX4' in the
-      bootblock, it seems to me the savest way to ensure that the mounted
-      device is in fact a QNX4 partition.
-      Done 20-06-1998, Frank. But some disks (like QNX install floppies)
-      don't have 'QNX4' in their bootblock.
-      
-    - Bitmap functions. To find out the free space, largest free block, etc.
-      Partly done (RO), Richard, 05/06/1998. Optimized 20-06-1998, Frank.
-    
-    - Complete write, unlink and truncate functions : the bitmap should be
-updated.
-
-    - Porting to linux 2.1.99+ with dcache support. 20-06-1998, Frank.
-    
-    - Don't rewrite the file_read function : use the generic_file_read hook,
-      and write readpage instead. Done on 21-06-1998, Frank.
-
-    - Write dinit and dcheck.
-
-    - Solving the bugs.
-    
-    - Use le32_to_cpu and vice-versa for portability.
diff -u --recursive linux-2.4.18-pre7/fs/qnx4/inode.c linux/fs/qnx4/inode.c
--- linux-2.4.18-pre7/fs/qnx4/inode.c	Wed Jan 30 21:10:50 2002
+++ linux/fs/qnx4/inode.c	Wed Jan 30 21:01:18 2002
@@ -351,25 +351,18 @@
 	s->s_blocksize = QNX4_BLOCK_SIZE;
 	s->s_blocksize_bits = QNX4_BLOCK_SIZE_BITS;
 
-	/* Check the boot signature. Since the qnx4 code is
+	/* Check the superblock signature. Since the qnx4 code is
 	   dangerous, we should leave as quickly as possible
 	   if we don't belong here... */
-	bh = sb_bread(s, 0);
+	bh = sb_bread(s, 1);
 	if (!bh) {
-		printk("qnx4: unable to read the boot sector\n");
+		printk("qnx4: unable to read the superblock\n");
 		goto outnobh;
 	}
-	if ( memcmp( (char*)bh->b_data + 4, "QNX4FS", 6 ) ) {
+	if ( le32_to_cpu( *(__u32*)bh->b_data ) != QNX4_SUPER_MAGIC ) {
 		if (!silent)
-			printk("qnx4: wrong fsid in boot sector.\n");
+			printk("qnx4: wrong fsid in superblock sector.\n");
 		goto out;
-	}
-	brelse(bh);
-
-	bh = sb_bread(s, 1);
-	if (!bh) {
-		printk("qnx4: unable to read the superblock\n");
-		goto outnobh;
 	}
 	s->s_op = &qnx4_sops;
 	s->s_magic = QNX4_SUPER_MAGIC;