Re: RFC: Modularize /proc/partitons (was Re: /proc/partitions for LVM)

From: Heinz J. Mauelshagen (Heinz.Mauelshagen@t-online.de)
Date: Fri Nov 24 2000 - 06:48:23 EST


Looks good to me.

Regards,
Heinz -- The LVM guy --

On Thu, Nov 23, 2000 at 02:52:39PM -0500, Brian Kress wrote:
> "Heinz J. Mauelshagen" wrote:
> >
> > On Wed, Nov 22, 2000 at 04:27:51PM -0500, Brian Kress wrote:
> > > "Heinz J. Mauelshagen" wrote:
> > > >
> > > > On Wed, Nov 22, 2000 at 04:05:39PM -0500, Brian Kress wrote:
> > > > > Question about /proc/partitions and LVM. LVM devices in
> > > > > /proc/partitions currently show up as lvma, lvmb, etc, depending on
> > > > > their device number. This breaks things like mount by filesystem
> > > > > name. Back when LVM existed as a patch, I believe there was some
> > > > > support in fs/partitions/check.c for showing the proper name for
> > > > > the device (something like <vgname>/<lvname>).
> > > >
> > > > Yes.
> > > > It actually was <vgname>/<lvname>.
> > > >
> > > > Linus didn't accept it though.
> > > >
> > > > The code is still available in case he changes his mind.
> > >
> > > Yes, I can see that now looking through lvm.c. (LVM_HD_NAME)
> > > I'm guessing why he didn't take it is the minor hack of adding a
> > > function pointer to genhd.c as a special case just for LVM.
> > > A general solution to this problem would be nice. The
> > > big switch statement in disk_name in fs/paritions/check.c is kind
> > > of ugly as it has generic code have to know things about specific
> > > drivers.
> >
> > Yep.
> >
> > > How's this for an idea to generalize this. Put a function
> > > pointer in the gendisk structure for a specific function to call
> > > for disk_name for disks for that gendisk.
> >
> > Sounds resonable to me.
> >
> > > That way, LVM gets its
> > > <vgname>/<lvname>, IDE gets its two disks per major (special cased
> > > right now), all the other special cases get what they need and future
> > > drivers can call their devices whatever they like without touching
> > > this file. Makes the whole thing more modular. Make a NULL for
> > > this function default to the old <name>a, <name>b, etc.
> > > What to people think about this? If this sounds reasonable
> > > I can come up with a patch.
> >
> > Very good. I'ld appreciate it.
> >
>
>
> OK, here's the patch. It has three sets of changes:
>
> 1) Add a function pointer to struct gendisk called hd_name.
>
> 2) Make disk_name in fs/partitions/check.c use that function
> pointer if its non-null.
>
> 3) Change the following drivers to use this method. (adding the
> driver specific method and removing the old code in check.c)
>
> drivers/md/lvm.c
> drivers/md/md.c
> drivers/ide/ide-probe.c
> drivers/scsi/sd.c
> drivers/block/cpqarray.c
> drivers/block/cciss.c
> drivers/block/DAC960.c
>
>
> Let me know what you think. Think there's any chance we
> can get this in the main kernel tree?

Linus can answer that one ;-)

>
>
> Brian Kress
> kressb@fsc-usa.com
> diff -u --recursive linux-2.4.0-test11/drivers/block/DAC960.c linux-2.4.0-test11-ppfix/drivers/block/DAC960.c
> --- linux-2.4.0-test11/drivers/block/DAC960.c Mon Nov 20 15:17:25 2000
> +++ linux-2.4.0-test11-ppfix/drivers/block/DAC960.c Thu Nov 23 14:29:37 2000
> @@ -1885,6 +1885,21 @@
> }
>
>
> +char *DAC960_disk_name(struct gendisk *hd, int minor, char *buf)
> +
> +{
> + int ctlr = hd->major - DAC960_MAJOR;
> + int disk = minor >> hd->minor_shift;
> + int part = minor & ((1 << hd->minor_shift) - 1);
> +
> + if (part)
> + sprintf(buf, "%s/c%dd%dp%d", hd->major_name, ctlr, disk, part);
> + else
> + sprintf(buf, "%s/c%dd%d", hd->major_name, ctlr, disk);
> + return buf;
> +}
> +
> +
> /*
> DAC960_RegisterBlockDevice registers the Block Device structures
> associated with Controller.
> @@ -1945,6 +1960,7 @@
> Controller->GenericDiskInfo.nr_real = Controller->LogicalDriveCount;
> Controller->GenericDiskInfo.next = NULL;
> Controller->GenericDiskInfo.fops = &DAC960_BlockDeviceOperations;
> + Controller->GenericDiskInfo.hd_name = DAC960_disk_name;
> /*
> Install the Generic Disk Information structure at the end of the list.
> */
> diff -u --recursive linux-2.4.0-test11/drivers/block/cciss.c linux-2.4.0-test11-ppfix/drivers/block/cciss.c
> --- linux-2.4.0-test11/drivers/block/cciss.c Mon Nov 20 15:17:25 2000
> +++ linux-2.4.0-test11-ppfix/drivers/block/cciss.c Thu Nov 23 14:22:55 2000
> @@ -1749,6 +1749,20 @@
> kfree(size_buff);
> }
>
> +char *cciss_disk_name(struct gendisk *hd, int minor, char *buf)
> +
> +{
> + int ctlr = hd->major - COMPAQ_CISS_MAJOR;
> + int disk = minor >> hd->minor_shift;
> + int part = minor & ((1 << hd->minor_shift) - 1);
> +
> + if (part)
> + sprintf(buf, "%s/c%dd%dp%d", hd->major_name, ctlr, disk, part);
> + else
> + sprintf(buf, "%s/c%dd%d", hd->major_name, ctlr, disk);
> + return buf;
> +}
> +
> /*
> * This is it. Find all the controllers and register them. I really hate
> * stealing all these major device numbers.
> @@ -1851,6 +1865,7 @@
> hba[i]->gendisk.part = hba[i]->hd;
> hba[i]->gendisk.sizes = hba[i]->sizes;
> hba[i]->gendisk.nr_real = hba[i]->num_luns;
> + hba[i]->gendisk.hd_name = cciss_disk_name;
>
> /* Get on the disk list */
> hba[i]->gendisk.next = gendisk_head;
> diff -u --recursive linux-2.4.0-test11/drivers/block/cpqarray.c linux-2.4.0-test11-ppfix/drivers/block/cpqarray.c
> --- linux-2.4.0-test11/drivers/block/cpqarray.c Mon Nov 20 15:20:29 2000
> +++ linux-2.4.0-test11-ppfix/drivers/block/cpqarray.c Thu Nov 23 14:14:03 2000
> @@ -362,6 +362,20 @@
> }
> #endif /* MODULE */
>
> +char *ida_disk_name(struct gendisk *hd, int minor, char *buf)
> +
> +{
> + int ctlr = hd->major - COMPAQ_SMART2_MAJOR;
> + int disk = minor >> hd->minor_shift;
> + int part = minor & ((1 << hd->minor_shift) - 1);
> +
> + if (part)
> + sprintf(buf, "%s/c%dd%dp%d", hd->major_name, ctlr, disk, part);
> + else
> + sprintf(buf, "%s/c%dd%d", hd->major_name, ctlr, disk);
> + return buf;
> +}
> +
> /*
> * This is it. Find all the controllers and register them. I really hate
> * stealing all these major device numbers.
> @@ -512,6 +526,7 @@
> ida_gendisk[i].part = ida + (i*256);
> ida_gendisk[i].sizes = ida_sizes + (i*256);
> ida_gendisk[i].nr_real = 0;
> + ida_gendisk[i].hd_name = ida_disk_name;
>
> /* Get on the disk list */
> ida_gendisk[i].next = gendisk_head;
> diff -u --recursive linux-2.4.0-test11/drivers/ide/ide-probe.c linux-2.4.0-test11-ppfix/drivers/ide/ide-probe.c
> --- linux-2.4.0-test11/drivers/ide/ide-probe.c Thu Aug 3 19:29:49 2000
> +++ linux-2.4.0-test11-ppfix/drivers/ide/ide-probe.c Thu Nov 23 12:32:16 2000
> @@ -726,6 +726,40 @@
> return 0;
> }
>
> +char* ide_disk_name(struct gendisk *hd, int minor, char *buf)
> +
> +{
> + int unit = (minor >> hd->minor_shift) + 'a';
> + unsigned int part = minor & ((1 << hd->minor_shift) - 1);
> +
> + switch (hd->major) {
> + case IDE9_MAJOR:
> + unit += 2;
> + case IDE8_MAJOR:
> + unit += 2;
> + case IDE7_MAJOR:
> + unit += 2;
> + case IDE6_MAJOR:
> + unit += 2;
> + case IDE5_MAJOR:
> + unit += 2;
> + case IDE4_MAJOR:
> + unit += 2;
> + case IDE3_MAJOR:
> + unit += 2;
> + case IDE2_MAJOR:
> + unit += 2;
> + case IDE1_MAJOR:
> + unit += 2;
> + case IDE0_MAJOR:
> + }
> + if (part)
> + sprintf(buf, "hd%c%d", unit, part);
> + else
> + sprintf(buf, "hd%c", unit);
> + return buf;
> +}
> +
> /*
> * init_gendisk() (as opposed to ide_geninit) is called for each major device,
> * after probing for drives, to allocate partition tables and other data
> @@ -781,6 +815,7 @@
> gd->fops = ide_fops; /* file operations */
> gd->de_arr = kmalloc (sizeof *gd->de_arr * units, GFP_KERNEL);
> gd->flags = kmalloc (sizeof *gd->flags * units, GFP_KERNEL);
> + gd->hd_name = ide_disk_name;
> if (gd->de_arr)
> memset (gd->de_arr, 0, sizeof *gd->de_arr * units);
> if (gd->flags)
> diff -u --recursive linux-2.4.0-test11/drivers/md/lvm.c linux-2.4.0-test11-ppfix/drivers/md/lvm.c
> --- linux-2.4.0-test11/drivers/md/lvm.c Mon Nov 20 15:20:30 2000
> +++ linux-2.4.0-test11-ppfix/drivers/md/lvm.c Thu Nov 23 07:47:20 2000
> @@ -213,9 +213,7 @@
> &lvm_proc_get_info;
> #endif
>
> -#ifdef LVM_HD_NAME
> -void lvm_hd_name(char *, int);
> -#endif
> +char *lvm_hd_name(struct gendisk *, int, char *);
> /* End external function prototypes */
>
>
> @@ -230,9 +228,6 @@
> int lvm_snapshot_alloc(lv_t *);
> void lvm_snapshot_release(lv_t *);
>
> -#ifdef LVM_HD_NAME
> -extern void (*lvm_hd_name_ptr) (char *, int);
> -#endif
> static int lvm_map(struct buffer_head *, int);
> static int lvm_do_lock_lvm(void);
> static int lvm_do_le_remap(vg_t *, void *);
> @@ -397,11 +392,6 @@
> lvm_gendisk.next = NULL;
> }
>
> -#ifdef LVM_HD_NAME
> - /* reference from drivers/block/genhd.c */
> - lvm_hd_name_ptr = lvm_hd_name;
> -#endif
> -
> blk_init_queue(BLK_DEFAULT_QUEUE(MAJOR_NR), DEVICE_REQUEST);
> blk_queue_make_request(BLK_DEFAULT_QUEUE(MAJOR_NR), lvm_make_request_fn);
> blk_queue_pluggable(BLK_DEFAULT_QUEUE(MAJOR_NR), lvm_plug_device_noop);
> @@ -460,11 +450,6 @@
> remove_proc_entry(LVM_NAME, &proc_root);
> #endif
>
> -#ifdef LVM_HD_NAME
> - /* reference from linux/drivers/block/genhd.c */
> - lvm_hd_name_ptr = NULL;
> -#endif
> -
> printk(KERN_INFO "%s -- Module successfully deactivated\n", lvm_name);
>
> return;
> @@ -1448,24 +1433,22 @@
> * internal support functions
> */
>
> -#ifdef LVM_HD_NAME
> /*
> * generate "hard disk" name
> */
> -void lvm_hd_name(char *buf, int minor)
> +char *lvm_hd_name(struct gendisk *hd, int minor, char *buf)
> {
> int len = 0;
> lv_t *lv_ptr;
>
> if (vg[VG_BLK(minor)] == NULL ||
> (lv_ptr = vg[VG_BLK(minor)]->lv[LV_BLK(minor)]) == NULL)
> - return;
> + return buf;
> len = strlen(lv_ptr->lv_name) - 5;
> memcpy(buf, &lv_ptr->lv_name[5], len);
> buf[len] = 0;
> - return;
> + return buf;
> }
> -#endif
>
>
> /*
> @@ -2515,6 +2498,8 @@
>
> blksize_size[MAJOR_NR] = lvm_blocksizes;
> blk_size[MAJOR_NR] = lvm_size;
> +
> + lvm_gendisk.hd_name=lvm_hd_name;
>
> return;
> } /* lvm_gen_init() */
> diff -u --recursive linux-2.4.0-test11/drivers/md/md.c linux-2.4.0-test11-ppfix/drivers/md/md.c
> --- linux-2.4.0-test11/drivers/md/md.c Mon Nov 20 15:20:30 2000
> +++ linux-2.4.0-test11-ppfix/drivers/md/md.c Thu Nov 23 07:56:06 2000
> @@ -113,6 +113,8 @@
> extern struct block_device_operations md_fops;
> static devfs_handle_t devfs_handle;
>
> +char *md_disk_name(struct gendisk*, int, char *);
> +
> static struct gendisk md_gendisk=
> {
> major: MD_MAJOR,
> @@ -125,6 +127,7 @@
> real_devices: NULL,
> next: NULL,
> fops: &md_fops,
> + hd_name: md_disk_name,
> };
>
> /*
> @@ -215,6 +218,14 @@
> MOD_INC_USE_COUNT;
>
> return mddev;
> +}
> +
> +char * md_disk_name(struct gendisk *hd, int minor, char* buf)
> +
> +{
> + int unit = (minor >> hd->minor_shift) + '0';
> + sprintf(buf, "%s%c", hd->major_name, unit);
> + return buf;
> }
>
> struct gendisk * find_gendisk (kdev_t dev)
> diff -u --recursive linux-2.4.0-test11/drivers/scsi/sd.c linux-2.4.0-test11-ppfix/drivers/scsi/sd.c
> --- linux-2.4.0-test11/drivers/scsi/sd.c Mon Nov 20 15:17:18 2000
> +++ linux-2.4.0-test11-ppfix/drivers/scsi/sd.c Thu Nov 23 09:53:01 2000
> @@ -1013,6 +1013,30 @@
> return i;
> }
>
> +char *scsi_disk_name(struct gendisk *hd, int minor, char *buf)
> +
> +{
> + int unit = (minor >> hd->minor_shift) + 'a';
> + unsigned int part = minor & ((1 << hd->minor_shift) - 1);
> +
> + if (hd->major >= SCSI_DISK1_MAJOR && hd->major <= SCSI_DISK7_MAJOR) {
> + unit = unit + (hd->major - SCSI_DISK1_MAJOR + 1) * 16;
> + if (unit > 'z') {
> + unit -= 'z' + 1;
> + sprintf(buf, "sd%c%c", 'a' + unit / 26, 'a' + unit % 26);
> + if (part)
> + sprintf(buf + 4, "%d", part);
> + return buf;
> + }
> + }
> +
> + if (part)
> + sprintf(buf, "sd%c%d", unit, part);
> + else
> + sprintf(buf, "sd%c", unit);
> + return buf;
> +}
> +
> /*
> * The sd_init() function looks at all SCSI drives present, determines
> * their size, and reads partition table entries for them.
> @@ -1109,6 +1133,7 @@
> sd_gendisks[i].next = sd_gendisks + i + 1;
> sd_gendisks[i].real_devices =
> (void *) (rscsi_disks + i * SCSI_DISKS_PER_MAJOR);
> + sd_gendisks[i].hd_name=scsi_disk_name;
> }
>
> LAST_SD_GENDISK.next = NULL;
> diff -u --recursive linux-2.4.0-test11/fs/partitions/check.c linux-2.4.0-test11-ppfix/fs/partitions/check.c
> --- linux-2.4.0-test11/fs/partitions/check.c Mon Nov 20 15:17:27 2000
> +++ linux-2.4.0-test11-ppfix/fs/partitions/check.c Thu Nov 23 14:30:45 2000
> @@ -83,11 +83,10 @@
> */
> char *disk_name (struct gendisk *hd, int minor, char *buf)
> {
> - unsigned int part;
> const char *maj = hd->major_name;
> int unit = (minor >> hd->minor_shift) + 'a';
> + unsigned int part = minor & ((1 << hd->minor_shift) - 1);
>
> - part = minor & ((1 << hd->minor_shift) - 1);
> if (hd->part[minor].de) {
> int pos;
>
> @@ -95,77 +94,8 @@
> if (pos >= 0)
> return buf + pos;
> }
> - /*
> - * IDE devices use multiple major numbers, but the drives
> - * are named as: {hda,hdb}, {hdc,hdd}, {hde,hdf}, {hdg,hdh}..
> - * This requires special handling here.
> - */
> - switch (hd->major) {
> - case IDE9_MAJOR:
> - unit += 2;
> - case IDE8_MAJOR:
> - unit += 2;
> - case IDE7_MAJOR:
> - unit += 2;
> - case IDE6_MAJOR:
> - unit += 2;
> - case IDE5_MAJOR:
> - unit += 2;
> - case IDE4_MAJOR:
> - unit += 2;
> - case IDE3_MAJOR:
> - unit += 2;
> - case IDE2_MAJOR:
> - unit += 2;
> - case IDE1_MAJOR:
> - unit += 2;
> - case IDE0_MAJOR:
> - maj = "hd";
> - break;
> - case MD_MAJOR:
> - unit -= 'a'-'0';
> - break;
> - }
> - if (hd->major >= SCSI_DISK1_MAJOR && hd->major <= SCSI_DISK7_MAJOR) {
> - unit = unit + (hd->major - SCSI_DISK1_MAJOR + 1) * 16;
> - if (unit > 'z') {
> - unit -= 'z' + 1;
> - sprintf(buf, "sd%c%c", 'a' + unit / 26, 'a' + unit % 26);
> - if (part)
> - sprintf(buf + 4, "%d", part);
> - return buf;
> - }
> - }
> - if (hd->major >= COMPAQ_SMART2_MAJOR && hd->major <= COMPAQ_SMART2_MAJOR+7) {
> - int ctlr = hd->major - COMPAQ_SMART2_MAJOR;
> - int disk = minor >> hd->minor_shift;
> - int part = minor & (( 1 << hd->minor_shift) - 1);
> - if (part == 0)
> - sprintf(buf, "%s/c%dd%d", maj, ctlr, disk);
> - else
> - sprintf(buf, "%s/c%dd%dp%d", maj, ctlr, disk, part);
> - return buf;
> - }
> - if (hd->major >= COMPAQ_CISS_MAJOR && hd->major <= COMPAQ_CISS_MAJOR+7) {
> - int ctlr = hd->major - COMPAQ_CISS_MAJOR;
> - int disk = minor >> hd->minor_shift;
> - int part = minor & (( 1 << hd->minor_shift) - 1);
> - if (part == 0)
> - sprintf(buf, "%s/c%dd%d", maj, ctlr, disk);
> - else
> - sprintf(buf, "%s/c%dd%dp%d", maj, ctlr, disk, part);
> - return buf;
> - }
> - if (hd->major >= DAC960_MAJOR && hd->major <= DAC960_MAJOR+7) {
> - int ctlr = hd->major - DAC960_MAJOR;
> - int disk = minor >> hd->minor_shift;
> - int part = minor & (( 1 << hd->minor_shift) - 1);
> - if (part == 0)
> - sprintf(buf, "%s/c%dd%d", maj, ctlr, disk);
> - else
> - sprintf(buf, "%s/c%dd%dp%d", maj, ctlr, disk, part);
> - return buf;
> - }
> + if (hd->hd_name) return hd->hd_name(hd, minor, buf);
> +
> if (part)
> sprintf(buf, "%s%c%d", maj, unit, part);
> else
> diff -u --recursive linux-2.4.0-test11/include/linux/genhd.h linux-2.4.0-test11-ppfix/include/linux/genhd.h
> --- linux-2.4.0-test11/include/linux/genhd.h Mon Nov 20 15:31:01 2000
> +++ linux-2.4.0-test11-ppfix/include/linux/genhd.h Thu Nov 23 07:44:35 2000
> @@ -72,6 +72,8 @@
>
> devfs_handle_t *de_arr; /* one per physical disc */
> char *flags; /* one per physical disc */
> +
> + char *(*hd_name) (struct gendisk *, int, char *);
> };
> #endif /* __KERNEL__ */
>

=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-

Heinz Mauelshagen Sistina Software Inc.
Senior Consultant/Developer Bartningstr. 12
                                                  64289 Darmstadt
                                                  Germany
Mauelshagen@Sistina.com +49 6151 7103 86
                                                       FAX 7103 96
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This archive was generated by hypermail 2b29 : Thu Nov 30 2000 - 21:00:11 EST