/*
* Partition table and disk geometry handling
*
* This obsoletes the partition-handling code in genhd.c:
* Userspace can look at a disk in arbitrary format and tell
* the kernel what partitions there are on the disk, and how
* these should be numbered.
* It also allows one to repartition a disk that is being used.
*
* A single ioctl with lots of subfunctions:
*
* Device number stuff:
* get_whole_disk() (given the device number of a partition, find
* the device number of the encompassing disk)
* get_all_partitions() (given the device number of a disk, return the
* device numbers of all its known partitions)
*
* Partition stuff:
* add_partition()
* delete_partition()
* test_partition_in_use() (also for test_disk_in_use)
*
* Geometry stuff:
* get_geometry()
* set_geometry()
* get_bios_drivedata()
*
* For today, only the partition stuff - aeb, 990515
*/
#include <linux/errno.h>
#include <linux/fs.h> /* for BLKRASET, ... */
#include <linux/sched.h> /* for capable() */
#include <linux/blk.h> /* for set_device_ro() */
#include <linux/blkpg.h>
#include <linux/genhd.h>
#include <linux/swap.h> /* for is_swap_partition() */
#include <linux/module.h> /* for EXPORT_SYMBOL */
#include <asm/uaccess.h>
/*
* What is the data describing a partition?
*
* 1. a device number (kdev_t)
* 2. a starting sector and number of sectors (hd_struct)
* given in the part[] array of the gendisk structure for the drive.
*
* The number of sectors is replicated in the sizes[] array of
* the gendisk structure for the major, which again is copied to
* the blk_size[][] array.
* (However, hd_struct has the number of 512-byte sectors,
* g->sizes[] and blk_size[][] have the number of 1024-byte blocks.)
* Note that several drives may have the same major.
*/
/* a linear search, superfluous when dev is a pointer */
58 static struct gendisk *get_gendisk(kdev_t dev) {
struct gendisk *g;
int m = MAJOR(dev);
62 for (g = gendisk_head; g; g = g->next)
63 if (g->major == m)
64 break;
65 return g;
}
/*
* Add a partition.
*
* returns: EINVAL: bad parameters
* ENXIO: cannot find drive
* EBUSY: proposed partition overlaps an existing one
* or has the same number as an existing one
* 0: all OK.
*/
77 int add_partition(kdev_t dev, struct blkpg_partition *p) {
struct gendisk *g;
long long ppstart, pplength;
long pstart, plength;
int i, drive, first_minor, end_minor, minor;
/* convert bytes to sectors, check for fit in a hd_struct */
ppstart = (p->start >> 9);
pplength = (p->length >> 9);
pstart = ppstart;
plength = pplength;
if (pstart != ppstart || plength != pplength
89 || pstart < 0 || plength < 0)
90 return -EINVAL;
/* find the drive major */
g = get_gendisk(dev);
94 if (!g)
95 return -ENXIO;
/* existing drive? */
drive = (MINOR(dev) >> g->minor_shift);
first_minor = (drive << g->minor_shift);
end_minor = first_minor + g->max_p;
101 if (drive >= g->nr_real)
102 return -ENXIO;
/* drive and partition number OK? */
105 if (first_minor != MINOR(dev) || p->pno <= 0 || p->pno >= g->max_p)
106 return -EINVAL;
/* partition number in use? */
minor = first_minor + p->pno;
110 if (g->part[minor].nr_sects != 0)
111 return -EBUSY;
/* overlap? */
114 for (i=first_minor+1; i<end_minor; i++)
if (!(pstart+plength <= g->part[i].start_sect ||
116 pstart >= g->part[i].start_sect + g->part[i].nr_sects))
117 return -EBUSY;
/* all seems OK */
g->part[minor].start_sect = pstart;
g->part[minor].nr_sects = plength;
122 if (g->sizes)
g->sizes[minor] = (plength >> (BLOCK_SIZE_BITS - 9));
124 return 0;
}
/*
* Delete a partition given by partition number
*
* returns: EINVAL: bad parameters
* ENXIO: cannot find partition
* EBUSY: partition is busy
* 0: all OK.
*
* Note that the dev argument refers to the entire disk, not the partition.
*/
137 int del_partition(kdev_t dev, struct blkpg_partition *p) {
struct gendisk *g;
kdev_t devp;
int drive, first_minor, minor;
/* find the drive major */
g = get_gendisk(dev);
144 if (!g)
145 return -ENXIO;
/* drive and partition number OK? */
drive = (MINOR(dev) >> g->minor_shift);
first_minor = (drive << g->minor_shift);
150 if (first_minor != MINOR(dev) || p->pno <= 0 || p->pno >= g->max_p)
151 return -EINVAL;
/* existing drive and partition? */
minor = first_minor + p->pno;
155 if (drive >= g->nr_real || g->part[minor].nr_sects == 0)
156 return -ENXIO;
/* partition in use? Incomplete check for now. */
devp = MKDEV(MAJOR(dev), minor);
if (get_super(devp) || /* mounted? */
161 is_swap_partition(devp))
162 return -EBUSY;
/* all seems OK */
fsync_dev(devp);
invalidate_buffers(devp);
g->part[minor].start_sect = 0;
g->part[minor].nr_sects = 0;
170 if (g->sizes)
g->sizes[minor] = 0;
173 return 0;
}
176 int blkpg_ioctl(kdev_t dev, struct blkpg_ioctl_arg *arg)
{
struct blkpg_ioctl_arg a;
struct blkpg_partition p;
int len;
182 if (copy_from_user(&a, arg, sizeof(struct blkpg_ioctl_arg)))
183 return -EFAULT;
185 switch (a.op) {
186 case BLKPG_ADD_PARTITION:
187 case BLKPG_DEL_PARTITION:
len = a.datalen;
189 if (len < sizeof(struct blkpg_partition))
190 return -EINVAL;
191 if (copy_from_user(&p, a.data, sizeof(struct blkpg_partition)))
192 return -EFAULT;
193 if (!capable(CAP_SYS_ADMIN))
194 return -EACCES;
195 if (a.op == BLKPG_ADD_PARTITION)
196 return add_partition(dev, &p);
197 else
198 return del_partition(dev, &p);
199 default:
200 return -EINVAL;
}
}
/*
* Common ioctl's for block devices
*/
208 int blk_ioctl(kdev_t dev, unsigned int cmd, unsigned long arg)
{
int intval;
212 switch (cmd) {
213 case BLKROSET:
214 if (!capable(CAP_SYS_ADMIN))
215 return -EACCES;
216 if (get_user(intval, (int *)(arg)))
217 return -EFAULT;
set_device_ro(dev, intval);
219 return 0;
220 case BLKROGET:
intval = (is_read_only(dev) != 0);
222 return put_user(intval, (int *)(arg));
224 case BLKRASET:
225 if(!capable(CAP_SYS_ADMIN))
226 return -EACCES;
227 if(!dev || arg > 0xff)
228 return -EINVAL;
read_ahead[MAJOR(dev)] = arg;
230 return 0;
231 case BLKRAGET:
232 if (!arg)
233 return -EINVAL;
234 return put_user(read_ahead[MAJOR(dev)], (long *) arg);
236 case BLKFLSBUF:
237 if(!capable(CAP_SYS_ADMIN))
238 return -EACCES;
239 if (!dev)
240 return -EINVAL;
fsync_dev(dev);
invalidate_buffers(dev);
243 return 0;
245 case BLKSSZGET:
/* get block device sector size as needed e.g. by fdisk */
intval = get_hardsect_size(dev);
248 return put_user(intval, (int *) arg);
#if 0
case BLKGETSIZE:
/* Today get_gendisk() requires a linear scan;
add this when dev has pointer type. */
g = get_gendisk(dev);
if (!g)
longval = 0;
else
longval = g->part[MINOR(dev)].nr_sects;
return put_user(longval, (long *) arg);
#endif
#if 0
case BLKRRPART: /* Re-read partition tables */
if (!capable(CAP_SYS_ADMIN))
return -EACCES;
return reread_partitions(dev, 1);
#endif
268 case BLKPG:
269 return blkpg_ioctl(dev, (struct blkpg_ioctl_arg *) arg);
271 case BLKELVGET:
return blkelvget_ioctl(&blk_get_queue(dev)->elevator,
273 (blkelv_ioctl_arg_t *) arg);
274 case BLKELVSET:
return blkelvset_ioctl(&blk_get_queue(dev)->elevator,
276 (blkelv_ioctl_arg_t *) arg);
278 default:
279 return -EINVAL;
}
}
EXPORT_SYMBOL(blk_ioctl);