keep devfs partition nodes in sync with block device drivers

(I'm resending this again... Richard Gooch raised some points last time, but I think I adequately answered those. There does not appear to be a "cleaner" solution to implement during 2.4, unless I've missed something obvious)

The attached patch (which touches nearly every block device driver that supports partitioned media) fixes a couple of problems when devfs is in use:

- when a block device's media is "revalidated", the partition table is re-read and /dev nodes are created for those partitions, but the previously existing entries are not removed first. this can easily lead to "left over" entries when the partition table is changed (either by partition table editing or replacement of removable media)

- if media is ejected from a removable media device (normally done using an ioctl), the /dev entries for that media do not get removed

- if a block device driver has sub-drivers (specifically the IDE layer) loaded as modules, and one of those sub-drivers is unloaded, the /dev nodes it was responsible for do not get removed. this problem will not occur if the main block driver (at the major number level) is unloaded, only for sub-drivers

The patch is against 2.4.8-pre1, but should apply to nearly any recent kernel version. I have tested that all the drivers compile (except for acsi and acorn/mfmhd since I don't have those platforms), and have tested the desired effects on the ide-floppy driver. In addition, there are very likely other block device drivers in other architecture trees that I did not touch as the code was not clearly understandable (to me at least). Comments welcome :-)

--- cut here ---
diff -rbwU3 --exclude-from=dontdiff linux-old/drivers/acorn/block/mfmhd.c linux-2.4/drivers/acorn/block/mfmhd.c

@@ -1492,6 +1492,7 @@
 
  /* Divide by 2, since sectors are 2 times smaller than usual ;-) */
 
+ ungrok_partitions(&mfm_gendisk, target);
  grok_partitions(&mfm_gendisk, target, 1<<6, mfm_info[target].heads *
       mfm_info[target].cylinders * mfm_info[target].sectors / 2);
 

diff -rbwU3 --exclude-from=dontdiff linux-old/drivers/block/DAC960.c linux-2.4/drivers/block/DAC960.c

@@ -5153,6 +5153,8 @@
    */
    set_blocksize(Device, BLOCK_SIZE);
  }
+      ungrok_partitions(&Controller->GenericDiskInfo,
+   LogicalDriveNumber);
       if (Controller->FirmwareType == DAC960_V1_Controller)
  grok_partitions(&Controller->GenericDiskInfo,
    LogicalDriveNumber,

diff -rbwU3 --exclude-from=dontdiff linux-old/drivers/block/acsi.c linux-2.4/drivers/block/acsi.c

@@ -1906,6 +1906,7 @@
  ENABLE_IRQ();
  stdma_release();
 
+ ungrok_partitions(gdev, device);
  grok_partitions(gdev, device, (aip->type==HARDDISK)?1<<4:1, aip->size);
 
  DEVICE_BUSY = 0;

diff -rbwU3 --exclude-from=dontdiff linux-old/drivers/block/cciss.c linux-2.4/drivers/block/cciss.c

@@ -736,6 +736,7 @@
                 blksize_size[MAJOR_NR+ctlr][minor] = 1024;
         }
  /* setup partitions per disk */
+        ungrok_partitions(gdev, target);
  grok_partitions(gdev, target, MAX_PART,
    hba[ctlr]->drv[target].nr_blocks);
         hba[ctlr]->drv[target].usage_count--;

diff -rbwU3 --exclude-from=dontdiff linux-old/drivers/block/cpqarray.c linux-2.4/drivers/block/cpqarray.c

@@ -1665,6 +1665,7 @@
   blksize_size[MAJOR_NR+ctlr][minor] = 1024;
  }
 
+ ungrok_partitions(gdev, target);
  /* 16 minors per disk... */
  grok_partitions(gdev, target, 16, hba[ctlr]->drv[target].nr_blks);
  hba[ctlr]->drv[target].usage_count--;

diff -rbwU3 --exclude-from=dontdiff linux-old/drivers/block/paride/pd.c linux-2.4/drivers/block/paride/pd.c

@@ -510,7 +510,10 @@
 
         switch (cmd) {
      case CDROMEJECT:
-  if (PD.access == 1) pd_eject(unit);
+  if (PD.access == 1) {
+                    ungrok_partitions(&pd_gendisk,unit);
+                    pd_eject(unit);
+  }
   return 0;
             case HDIO_GETGEO:
                 if (!geo) return -EINVAL;

@@ -609,8 +612,10 @@
                 pd_hd[minor].nr_sects = 0;
         }
 
- if (pd_identify(unit))
+ if (pd_identify(unit)) {
+                ungrok_partitions(&pd_gendisk,unit);
   grok_partitions(&pd_gendisk,unit,1<<PD_BITS,PD.capacity);
+ }
 
         pd_valid = 1;
         wake_up(&pd_wait_open);

diff -rbwU3 --exclude-from=dontdiff linux-old/drivers/block/ps2esdi.c linux-2.4/drivers/block/ps2esdi.c

@@ -1155,6 +1155,7 @@
   ps2esdi_gendisk.part[minor].nr_sects = 0;
  }
 
+ ungrok_partitions(&ps2esdi_gendisk, target);
  grok_partitions(&ps2esdi_gendisk, target, 1<<6,
   ps2esdi_info[target].head * ps2esdi_info[target].cyl *

ps2esdi_info[target].sect);

diff -rbwU3 --exclude-from=dontdiff linux-old/drivers/block/xd.c linux-2.4/drivers/block/xd.c

@@ -406,6 +406,7 @@
   xd_gendisk.part[minor].nr_sects = 0;
  };
 
+ ungrok_partitions(&xd_gendisk, target);
  grok_partitions(&xd_gendisk, target, 1<<6,
    xd_info[target].heads * xd_info[target].cylinders *

xd_info[target].sectors);

diff -rbwU3 --exclude-from=dontdiff linux-old/drivers/i2o/i2o_block.c linux-2.4/drivers/i2o/i2o_block.c

@@ -1441,6 +1441,7 @@
   */
  dev->req_queue = &i2ob_queues[c->unit]->req_queue;
 
+ ungrok_partitions(&i2ob_gendisk, unit>>4);
  grok_partitions(&i2ob_gendisk, unit>>4, 1<<4, (long)(size>>9));
 
  /*

diff -rbwU3 --exclude-from=dontdiff linux-old/drivers/ide/hd.c linux-2.4/drivers/ide/hd.c

@@ -901,6 +901,7 @@
  MAYBE_REINIT;
 #endif
 
+ ungrok_partitions(gdev, target);
  grok_partitions(gdev, target, 1<<6, CAPACITY);
 
  DEVICE_BUSY = 0;

diff -rbwU3 --exclude-from=dontdiff linux-old/drivers/ide/ide-disk.c linux-2.4/drivers/ide/ide-disk.c

@@ -494,6 +494,7 @@
 
 static void idedisk_revalidate (ide_drive_t *drive)
 {
+ ungrok_partitions(HWIF(drive)->gd, drive->select.b.unit);
  grok_partitions(HWIF(drive)->gd, drive->select.b.unit,
    1<<PARTN_BITS,
    current_capacity(drive));

@@ -728,6 +729,7 @@
 
 static int idedisk_cleanup (ide_drive_t *drive)
 {
+ ungrok_partitions(HWIF(drive)->gd, drive->select.b.unit);
  return ide_unregister_subdriver(drive);
 }
 

diff -rbwU3 --exclude-from=dontdiff linux-old/drivers/ide/ide-floppy.c linux-2.4/drivers/ide/ide-floppy.c

@@ -1293,7 +1293,7 @@
 /*
  * Our special ide-floppy ioctl's.
  *
- * Currently there aren't any ioctl's.
+ * Currently the only ioctl supported is to eject the cartridge, using the

CDROMEJECT ioctl.
*/
static int idefloppy_ioctl (ide_drive_t *drive, struct inode *inode, struct
file *file,
unsigned int cmd, unsigned long arg)
@@ -1307,6 +1307,7 @@
(void) idefloppy_queue_pc_tail (drive, &pc); idefloppy_create_start_stop_cmd (&pc, 2);
(void) idefloppy_queue_pc_tail (drive, &pc);
+ ungrok_partitions(HWIF(drive)->gd, drive->select.b.unit);
return 0;
}
return -EIO;
@@ -1380,6 +1381,7 @@
*/
static void idefloppy_revalidate (ide_drive_t *drive)
{
+ ungrok_partitions(HWIF(drive)->gd, drive->select.b.unit); grok_partitions(HWIF(drive)->gd, drive->select.b.unit,

    1<<PARTN_BITS,
    current_capacity(drive));

@@ -1577,6 +1579,7 @@
{
idefloppy_floppy_t *floppy = drive->driver_data;

+ ungrok_partitions(HWIF(drive)->gd, drive->select.b.unit); if (ide_unregister_subdriver (drive))
return 1;
drive->driver_data = NULL;
diff -rbwU3 --exclude-from=dontdiff linux-old/drivers/mtd/nftlcore.c linux-2.4/drivers/mtd/nftlcore.c

@@ -166,6 +166,7 @@
 #if LINUX_VERSION_CODE < 0x20328
  resetup_one_dev(&nftl_gendisk, firstfree);
 #else
+  ungrok_partitions(&nftl_gendisk, firstfree);
  grok_partitions(&nftl_gendisk, firstfree, 1<<NFTL_PARTN_BITS,

nftl->nr_sects);
#endif
}
@@ -824,6 +825,7 @@
#if LINUX_VERSION_CODE < 0x20328
resetup_one_dev(&nftl_gendisk, MINOR(inode->i_rdev) >> NFTL_PARTN_BITS);
#else
+ ungrok_partitions(&nftl_gendisk, MINOR(inode->i_rdev) >>
NFTL_PARTN_BITS);
grok_partitions(&nftl_gendisk, MINOR(inode->i_rdev) >> NFTL_PARTN_BITS,

     1<<NFTL_PARTN_BITS, nftl->nr_sects);

#endif
diff -rbwU3 --exclude-from=dontdiff linux-old/drivers/scsi/sd.c linux-2.4/drivers/scsi/sd.c

@@ -1310,6 +1310,7 @@
  MAYBE_REINIT;
 #endif
 
+ ungrok_partitions(&SD_GENDISK(target), target % SCSI_DISKS_PER_MAJOR);
  grok_partitions(&SD_GENDISK(target), target % SCSI_DISKS_PER_MAJOR,
    1<<4, CAPACITY);
 

diff -rbwU3 --exclude-from=dontdiff linux-old/fs/partitions/check.c linux-2.4/fs/partitions/check.c

@@ -308,7 +308,7 @@
  printk(" unknown partition table\n");
 setup_devfs:
  i = first_part_minor - 1;
- devfs_register_partitions (hd, i, hd->sizes ? 0 : 1);
+ devfs_register_partitions (hd, i, 0);
 }
 
 #ifdef CONFIG_DEVFS_FS

@@ -441,4 +441,11 @@
    dev->sizes[i] = dev->part[i].nr_sects >> (BLOCK_SIZE_BITS - 9);
   blk_size[dev->major] = dev->sizes;
  }
+}
+
+void ungrok_partitions(struct gendisk *dev, int drive)
+{
+ int first_minor = drive << dev->minor_shift;
+
+        devfs_register_partitions(dev, first_minor, 1);
 }

diff -rbwU3 --exclude-from=dontdiff linux-old/include/linux/blkdev.h linux-2.4/include/linux/blkdev.h

@@ -149,6 +149,7 @@
 extern struct sec_size * blk_sec[MAX_BLKDEV];
 extern struct blk_dev_struct blk_dev[MAX_BLKDEV];
 extern void grok_partitions(struct gendisk *dev, int drive, unsigned

minors, long size);
+extern void ungrok_partitions(struct gendisk *dev, int drive);
extern void register_disk(struct gendisk *dev, kdev_t first, unsigned
minors, struct block_device_operations *ops, long size);
extern void generic_make_request(int rw, struct buffer_head * bh); extern request_queue_t *blk_get_queue(kdev_t dev);
diff -rbwU3 --exclude-from=dontdiff linux-old/kernel/ksyms.c linux-2.4/kernel/ksyms.c

@@ -296,6 +296,7 @@
 EXPORT_SYMBOL(ioctl_by_bdev);
 EXPORT_SYMBOL(gendisk_head);
 EXPORT_SYMBOL(grok_partitions);
+EXPORT_SYMBOL(ungrok_partitions);
 EXPORT_SYMBOL(register_disk);
 EXPORT_SYMBOL(tq_disk);
 EXPORT_SYMBOL(init_buffer);

Just because I haven't responded yet doesn't mean I agree. I am still not happy with this approach. Some other approach is needed. I have some ideas, but haven't had the chance to sit and think about it.

Please don't keep trying to force this patch in. I will get to it in the fullness of time, but I'm travelling at the moment.

				Regards,

					Richard....
Permanent: [email protected]
Current:   [email protected]