[PATCH 1/2] Put back BLKPG ioctls
Phillip Susi
psusi at cfl.rr.com
Tue Mar 30 19:04:43 UTC 2010
This patch effectively reverses commit 1d8f9bec which removed the code
using the new BLKPG ioctls instead of the old BLKRRPART ioctl to update
the in-kernel partition table. The reason for this is because BLKRRPART
fails if any partition on the disk is in use, but the BLKPG ioctls allow
you to manipulate the other partitions on the disk without requiring a
reboot. Also BLKRRPART requires that the kernel understand the
partition table on the disk, which may not always be the case.
---
libparted/arch/linux.c | 208 +++++++++++++++++++++++++++++++++++++++++++++++-
1 files changed, 205 insertions(+), 3 deletions(-)
diff --git a/libparted/arch/linux.c b/libparted/arch/linux.c
index c75cf9e..0344a99 100644
--- a/libparted/arch/linux.c
+++ b/libparted/arch/linux.c
@@ -19,7 +19,7 @@
#include <config.h>
#include <arch/linux.h>
-
+#include <linux/blkpg.h>
#include <parted/parted.h>
#include <parted/debug.h>
#if defined __s390__ || defined __s390x__
@@ -2297,6 +2297,182 @@ linux_partition_is_busy (const PedPartition* part)
return 0;
}
+static int
+_blkpg_part_command (PedDevice* dev, struct blkpg_partition* part, int op)
+{
+ LinuxSpecific* arch_specific = LINUX_SPECIFIC (dev);
+ struct blkpg_ioctl_arg ioctl_arg;
+
+ ioctl_arg.op = op;
+ ioctl_arg.flags = 0;
+ ioctl_arg.datalen = sizeof (struct blkpg_partition);
+ ioctl_arg.data = (void*) part;
+
+ return ioctl (arch_specific->fd, BLKPG, &ioctl_arg) == 0;
+}
+
+static int
+_blkpg_add_partition (PedDisk* disk, const PedPartition *part)
+{
+ struct blkpg_partition linux_part;
+ const char* vol_name;
+ char* dev_name;
+
+ PED_ASSERT(disk != NULL, return 0);
+ PED_ASSERT(disk->dev->sector_size % PED_SECTOR_SIZE_DEFAULT == 0,
+ return 0);
+
+ if (!_has_partitions (disk))
+ return 0;
+
+ if (ped_disk_type_check_feature (disk->type,
+ PED_DISK_TYPE_PARTITION_NAME))
+ vol_name = ped_partition_get_name (part);
+ else
+ vol_name = NULL;
+
+ dev_name = _device_get_part_path (disk->dev, part->num);
+ if (!dev_name)
+ return 0;
+
+ memset (&linux_part, 0, sizeof (linux_part));
+ linux_part.start = part->geom.start * disk->dev->sector_size;
+ /* see fs/partitions/msdos.c:msdos_partition(): "leave room for LILO" */
+ if (part->type & PED_PARTITION_EXTENDED)
+ linux_part.length = part->geom.length == 1 ? 512 : 1024;
+ else
+ linux_part.length = part->geom.length * disk->dev->sector_size;
+ linux_part.pno = part->num;
+ strncpy (linux_part.devname, dev_name, BLKPG_DEVNAMELTH);
+ if (vol_name)
+ strncpy (linux_part.volname, vol_name, BLKPG_VOLNAMELTH);
+
+ free (dev_name);
+
+ if (!_blkpg_part_command (disk->dev, &linux_part,
+ BLKPG_ADD_PARTITION)) {
+ return ped_exception_throw (
+ PED_EXCEPTION_ERROR,
+ PED_EXCEPTION_IGNORE_CANCEL,
+ _("Error informing the kernel about modifications to "
+ "partition %s -- %s. This means Linux won't know "
+ "about any changes you made to %s until you reboot "
+ "-- so you shouldn't mount it or use it in any way "
+ "before rebooting."),
+ linux_part.devname,
+ strerror (errno),
+ linux_part.devname)
+ == PED_EXCEPTION_IGNORE;
+ }
+
+ return 1;
+}
+
+static int
+_blkpg_remove_partition (PedDisk* disk, int n)
+{
+ struct blkpg_partition linux_part;
+
+ if (!_has_partitions (disk))
+ return 0;
+
+ memset (&linux_part, 0, sizeof (linux_part));
+ linux_part.pno = n;
+ return _blkpg_part_command (disk->dev, &linux_part,
+ BLKPG_DEL_PARTITION);
+}
+
+/*
+ * The number of partitions that a device can have depends on the kernel.
+ * If we don't find this value in /sys/block/DEV/range, we will use our own
+ * value.
+ */
+static unsigned int
+_device_get_partition_range(PedDevice* dev)
+{
+ int range, r;
+ char path[128];
+ FILE* fp;
+ bool ok;
+
+ r = snprintf(path, sizeof(path), "/sys/block/%s/range",
+ last_component(dev->path));
+ if(r < 0 || r >= sizeof(path))
+ return MAX_NUM_PARTS;
+
+ fp = fopen(path, "r");
+ if(!fp)
+ return MAX_NUM_PARTS;
+
+ ok = fscanf(fp, "%d", &range) == 1;
+ fclose(fp);
+
+ /* (range <= 0) is none sense.*/
+ return ok && range > 0 ? range : MAX_NUM_PARTS;
+}
+
+/*
+ * Sync the partition table in two step process:
+ * 1. Remove all of the partitions from the kernel's tables, but do not attempt
+ * removal of any partition for which the corresponding ioctl call fails.
+ * 2. Add all the partitions that we hold in disk.
+ *
+ * To achieve this two step process we must calculate the minimum number of
+ * maximum possible partitions between what linux supports and what the label
+ * type supports. EX:
+ *
+ * number=MIN(max_parts_supported_in_linux,max_parts_supported_in_msdos_tables)
+ */
+static int
+_disk_sync_part_table (PedDisk* disk)
+{
+ PED_ASSERT(disk != NULL, return 0);
+ PED_ASSERT(disk->dev != NULL, return 0);
+ int lpn;
+
+ /* lpn = largest partition number. */
+ if(ped_disk_get_max_supported_partition_count(disk, &lpn))
+ lpn = PED_MIN(lpn, _device_get_partition_range(disk->dev));
+ else
+ lpn = _device_get_partition_range(disk->dev);
+
+ /* Its not possible to support largest_partnum < 0.
+ * largest_partnum == 0 would mean does not support partitions.
+ * */
+ if(lpn < 0)
+ return 0;
+
+ int *rets = ped_malloc(sizeof(int) * lpn);
+ int *errnums = ped_malloc(sizeof(int) * lpn);
+ int ret = 1;
+ int i;
+
+ for (i = 1; i <= lpn; i++) {
+ rets[i - 1] = _blkpg_remove_partition (disk, i);
+ errnums[i - 1] = errno;
+ }
+
+ for (i = 1; i <= lpn; i++) {
+ const PedPartition *part = ped_disk_get_partition (disk, i);
+ if (part) {
+ /* busy... so we won't (can't!) disturb ;) Prolly
+ * doesn't matter anyway, because users shouldn't be
+ * changing mounted partitions anyway...
+ */
+ if (!rets[i - 1] && errnums[i - 1] == EBUSY)
+ continue;
+
+ /* add the (possibly modified or new) partition */
+ if (!_blkpg_add_partition (disk, part))
+ ret = 0;
+ }
+ }
+
+ free (rets);
+ free (errnums);
+ return ret;
+}
+
#ifdef ENABLE_DEVICE_MAPPER
static int
_dm_remove_map_name(char *name)
@@ -2544,16 +2720,42 @@ _kernel_reread_part_table (PedDevice* dev)
}
static int
+_have_blkpg ()
+{
+ static int have_blkpg = -1;
+ int kver;
+
+ if (have_blkpg != -1)
+ return have_blkpg;
+
+ kver = _get_linux_version();
+ return have_blkpg = kver >= KERNEL_VERSION (2,4,0) ? 1 : 0;
+}
+
+static int
linux_disk_commit (PedDisk* disk)
{
- if (!_has_partitions (disk))
- return 1;
+ if (!_has_partitions (disk))
+ return 1;
#ifdef ENABLE_DEVICE_MAPPER
if (disk->dev->type == PED_DEVICE_DM)
return _dm_reread_part_table (disk);
#endif
if (disk->dev->type != PED_DEVICE_FILE) {
+ /* The ioctl() command BLKPG_ADD_PARTITION does not notify
+ * the devfs system; consequently, /proc/partitions will not
+ * be up to date, and the proper links in /dev are not
+ * created. Therefore, if using DevFS, we must get the kernel
+ * to re-read and grok the partition table.
+ */
+ /* Work around kernel dasd problem so we really do BLKRRPART */
+ if (disk->dev->type != PED_DEVICE_DASD &&
+ _have_blkpg () ) {
+ if (_disk_sync_part_table (disk))
+ return 1;
+ }
+
return _kernel_reread_part_table (disk->dev);
}
--
1.6.3.3
--------------070105040404010604020208--
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