On 12/2/2011 3:50 AM, Petr Uzel wrote:
Hm, this code was hardly readable before and now with the ifdefs and
ifndefs, it is even harder not to get lost in it. Perhaps this could
be factored out somehow to separate function? Eventually also using
/sys/block/DEV/PART/start as a fallback if the new ioctl() is not
available?
http://lists.alioth.debian.org/pipermail/parted-devel/2011-November/003975.html
I merged your patch with mine. How does this look?
>From d45ed0d6cb2519464807f4185a5ad1644e802507 Mon Sep 17 00:00:00 2001
From: Phillip Susi <[email protected]>
Date: Wed, 30 Nov 2011 21:24:45 -0500
Subject: [PATCH] Avoid the HDIO_GETGEO when possible
We were using the long depreciated HDIO_GETGEO ioctl on the
partition to get its start sector. Use the new BLKPG_GET_PARTITION
ioctl instead. This allows for disks > 2TB and partitioned loop
devices, which don't support HDIO_GETGEO. As a fallback when
BLKPG_GET_PARTITION fails or is not availible, try getting the
values from sysfs, and finally use BLKGETSIZE64 and HDIO_GETGEO
as a last resort.
This modifies and superceeds Petr Uzel's patch:
libparted: fix reading partition start sector from kernel
---
libparted/arch/linux.c | 124 ++++++++++++++++++++++++++++++++++++++++-------
1 files changed, 105 insertions(+), 19 deletions(-)
diff --git a/libparted/arch/linux.c b/libparted/arch/linux.c
index 3799b9d..2d10b80 100644
--- a/libparted/arch/linux.c
+++ b/libparted/arch/linux.c
@@ -2410,6 +2410,25 @@ _blkpg_remove_partition (PedDisk* disk, int n)
BLKPG_DEL_PARTITION);
}
+#ifdef BLKPG_GET_PARTITION
+static int
+_blkpg_get_partition (PedPartition *part, long long *start, long long *length)
+{
+ struct blkpg_partition linux_part;
+ int ret;
+
+ memset (&linux_part, 0, sizeof (linux_part));
+ linux_part.pno = part->num;
+ if (_blkpg_part_command (part->disk->dev, &linux_part,
+ BLKPG_GET_PARTITION))
+ {
+ *start = linux_part.start;
+ *length = linux_part.length;
+ return 1;
+ } else return 0;
+}
+#endif
+
/* Read the integer from /sys/block/DEV_BASE/ENTRY and set *VAL
to that value, where DEV_BASE is the last component of DEV->path.
Upon success, return true. Otherwise, return false. */
@@ -2432,6 +2451,85 @@ _sysfs_int_entry_from_dev(PedDevice const* dev, const
char *entry, int *val)
return ok;
}
+/* Read the unsigned long long from /sys/block/DEV_BASE/PART_BASE/ENTRY
+ and set *VAL to that value, where DEV_BASE is the last component of path to
+ block device corresponding to PART and PART_BASE is the sysfs name of PART.
+ Upon success, return true. Otherwise, return false. */
+static bool
+_sysfs_ull_entry_from_part(PedPartition const* part, const char *entry,
unsigned long long *val)
+{
+ char path[128];
+ char *part_name = linux_partition_get_path(part);
+ if (!part_name)
+ return false;
+
+ int r = snprintf(path, sizeof(path), "/sys/block/%s/%s/%s",
+ last_component(part->disk->dev->path),
+ last_component(part_name), entry);
+ free(part_name);
+ if (r < 0 || r >= sizeof(path))
+ return false;
+
+ FILE *fp = fopen(path, "r");
+ if (!fp)
+ return false;
+
+ bool ok = fscanf(fp, "%llu", val) == 1;
+ fclose(fp);
+
+ return ok;
+}
+
+
+/* Get the starting sector and length of a partition PART within a block device
+ * Use blkpg if availible, then check sysfs and then use HDIO_GETGEO and
BLKGETSIZE64
+ * ioctls as fallback. Upon success, return true. Otherwise, return false. */
+static bool
+_kernel_get_partition_start_and_legnth(PedPartition const *part, unsigned long
long *start,
+ unsigned long long *length)
+{
+ int fd = -1;
+ int ok;
+ PED_ASSERT(part);
+ PED_ASSERT(start);
+ PED_ASSERT(length);
+
+#ifdef BLKPG_GET_PARTITION
+ ok = _blkpg_get_partition (part, start, length);
+ if (ok)
+ return ok;
+#endif
+ char *dev_name = linux_partition_get_path (part);
+ if (!dev_name)
+ return false;
+
+ ok = _sysfs_ull_entry_from_part (part, "start", start);
+ if (!ok) {
+ struct hd_geometry geom;
+ int fd = open (dev_name, O_RDONLY);
+ if (fd != -1 && ioctl (fd, HDIO_GETGEO, &geom)) {
+ *val = geom.start;
+ ok = true;
+ }
+ ok = _sysfs_ull_entry_from_part (part, "size", length);
+ if (!ok)
+ {
+ if (fd == -1)
+ fd = open (dev_name, O_RDONLY);
+ if (fd != -1 && ioctl (fd, BLKGETSIZE64, length))
+ ok = true;
+ }
+ if (ok)
+ *length /= part->disk->dev->sector_size;
+ if (fd != -1)
+ close (fd);
+
+ free (dev_name);
+ return ok;
+}
+
+
+
/*
* The number of partitions that a device can have depends on the kernel.
* If we don't find this value in /sys/block/DEV/ext_range, we will use our own
@@ -2519,30 +2617,18 @@ _disk_sync_part_table (PedDisk* disk)
const PedPartition *part = ped_disk_get_partition (disk, i);
if (part) {
if (!ok[i - 1] && errnums[i - 1] == EBUSY) {
- struct hd_geometry geom;
- unsigned long long length = 0;
+ unsigned long long length;
+ unsigned long long start;
/* get start and length of existing partition
*/
- char *dev_name = _device_get_part_path
(disk->dev, i);
- if (!dev_name)
- goto cleanup;
- int fd = open (dev_name, O_RDONLY);
- if (fd == -1
- || ioctl (fd, HDIO_GETGEO, &geom)
- || ioctl (fd, BLKGETSIZE64, &length)) {
+ if
(!_kernel_get_partition_start_and_length(part, &start, &length)) {
ped_exception_throw (
- PED_EXCEPTION_BUG,
-
PED_EXCEPTION_CANCEL,
+ PED_EXCEPTION_BUG,
+ PED_EXCEPTION_CANCEL,
_("Unable to determine the size and length of %s."),
- dev_name);
- if (fd != -1)
- close (fd);
- free (dev_name);
+ dev_name);
goto cleanup;
}
- free (dev_name);
- length /= disk->dev->sector_size;
- close (fd);
- if (geom.start == part->geom.start
+ if (start == part->geom.start
&& length == part->geom.length)
ok[i - 1] = 1;
/* If the new partition is unchanged and the
--
1.7.5.4
