88 lines
3.4 KiB
Diff
88 lines
3.4 KiB
Diff
From 503e98c49fa06512fd1b0318aba6ee5de6cbd7b4 Mon Sep 17 00:00:00 2001
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From: "Brian C. Lane" <bcl@redhat.com>
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Date: Tue, 8 Apr 2014 10:54:27 -0700
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Subject: [PATCH 88/91] libparted: Fix check for backup header location
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Add a couple of helper functions for calculating the partition table
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entry size (in sectors) and for guessing the end of the disk based on
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the LastUsableLBA and the Partition Table Entry size.
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The backup header should be either at the end of the disk, or at what
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the primary header thinks is the end of the disk. Prompt to fix the
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backup header if it is located any other place.
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* libparted/labels/gpt.c (_ptes_sectors): New function
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(_hdr_disk_end): New function
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(gpt_read): Use new function to test for pri's idea of end of disk
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---
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libparted/labels/gpt.c | 38 +++++++++++++++++++++++++++++++-------
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1 file changed, 31 insertions(+), 7 deletions(-)
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diff --git a/libparted/labels/gpt.c b/libparted/labels/gpt.c
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index 42b0360..c5dea2f 100644
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--- a/libparted/labels/gpt.c
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+++ b/libparted/labels/gpt.c
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@@ -693,6 +693,29 @@ _header_is_valid (PedDisk const *disk, GuidPartitionTableHeader_t *gpt,
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return crc == PED_LE32_TO_CPU (origcrc);
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}
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+/* Return the number of sectors that should be used by the
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+ * partition entry table.
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+ */
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+static PedSector
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+_ptes_sectors(PedDisk const *disk, GuidPartitionTableHeader_t const *gpt)
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+{
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+ size_t ptes_bytes = PED_LE32_TO_CPU (gpt->SizeOfPartitionEntry) *
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+ PED_LE32_TO_CPU (gpt->NumberOfPartitionEntries);
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+ /* Minimum amount of space reserved is 128 128 byte entries */
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+ if (ptes_bytes < 128*128)
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+ ptes_bytes = 128*128;
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+ return ped_div_round_up (ptes_bytes, disk->dev->sector_size);
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+}
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+
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+/* Return the header's idea of the last sector of the disk
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+ * based on LastUsableLBA and the Partition Entry table.
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+ */
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+static PedSector
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+_hdr_disk_end(PedDisk const *disk, GuidPartitionTableHeader_t const *gpt)
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+{
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+ return PED_LE64_TO_CPU (gpt->LastUsableLBA) + 1 + _ptes_sectors(disk, gpt);
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+}
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+
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static int
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_parse_header (PedDisk *disk, const GuidPartitionTableHeader_t *gpt,
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int *update_needed)
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@@ -985,13 +1008,14 @@ gpt_read (PedDisk *disk)
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{
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/* Both are valid. */
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#ifndef DISCOVER_ONLY
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- PedSector gpt_disk_end = PED_LE64_TO_CPU (primary_gpt->LastUsableLBA) + 1;
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- gpt_disk_end += ((PedSector) (PED_LE32_TO_CPU (primary_gpt->NumberOfPartitionEntries)) *
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- (PedSector) (PED_LE32_TO_CPU (primary_gpt->SizeOfPartitionEntry)) /
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- disk->dev->sector_size);
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-
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+ /* The backup header must be at the end of the disk, or at what the primary
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+ * header thinks is the end of the disk.
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+ */
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gpt_disk_data->AlternateLBA = PED_LE64_TO_CPU (primary_gpt->AlternateLBA);
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- if (PED_LE64_TO_CPU (primary_gpt->AlternateLBA) != gpt_disk_end)
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+ PedSector pri_disk_end = _hdr_disk_end(disk, primary_gpt);
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+
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+ if (gpt_disk_data->AlternateLBA != disk->dev->length -1 &&
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+ gpt_disk_data->AlternateLBA != pri_disk_end)
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{
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if (ped_exception_throw
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(PED_EXCEPTION_ERROR,
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@@ -1002,7 +1026,7 @@ gpt_read (PedDisk *disk)
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{
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ptt_clear_sectors (disk->dev,
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PED_LE64_TO_CPU (primary_gpt->AlternateLBA), 1);
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- gpt_disk_data->AlternateLBA = gpt_disk_end;
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+ gpt_disk_data->AlternateLBA = disk->dev->length -1;
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write_back = 1;
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}
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}
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--
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1.9.0
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