fix: correctly process GPT with gaps

There were two bugs related to processing partition tables with gaps (that is, partitions which do not exist). Signed-off-by: Andrey Smirnov <[email protected]>
siderolabs · Sep 23, 2024 · 33f603a · 33f603a
1 parent d39fa20
commit 33f603a
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Showing 4 changed files with 28 additions and 23 deletions.
diff --git a/partitioning/gpt/gpt.go b/partitioning/gpt/gpt.go
@@ -294,11 +294,12 @@ func (t *Table) allocatableRanges() []allocatableRange {
 
 	for {
 		for partitionIdx < len(t.entries) {
-			if t.entries[partitionIdx] == nil {
-				partitionIdx++
+			if t.entries[partitionIdx] != nil {
+				break
 			}
 
-			break
+			// skip empty entries
+			partitionIdx++
 		}
 
 		var highLBA uint64
@@ -634,12 +635,14 @@ func (t *Table) syncKernel() error {
 			}
 		}
 
-		err = t.dev.KernelPartitionAdd(no,
-			myEntry.FirstLBA*uint64(t.sectorSize),
-			(myEntry.LastLBA-myEntry.FirstLBA+1)*uint64(t.sectorSize),
-		)
-		if err != nil {
-			return fmt.Errorf("failed to add partition %d: %w", no, err)
+		if myEntry != nil {
+			err = t.dev.KernelPartitionAdd(no,
+				myEntry.FirstLBA*uint64(t.sectorSize),
+				(myEntry.LastLBA-myEntry.FirstLBA+1)*uint64(t.sectorSize),
+			)
+			if err != nil {
+				return fmt.Errorf("failed to add partition %d: %w", no, err)
+			}
 		}
 	}
 

diff --git a/partitioning/gpt/gpt_test.go b/partitioning/gpt/gpt_test.go
@@ -160,28 +160,30 @@ func TestGPT(t *testing.T) {
 			allocator: func(t *testing.T, table *gpt.Table) {
 				t.Helper()
 
-				// allocate 3 1G partitions first, and delete the middle one
+				// allocate 4 1G partitions first, and delete two in the middle
 
 				require.NoError(t, allocateError(table.AllocatePartition(1*GiB, "1G1", partType1,
 					gpt.WithUniqueGUID(uuid.MustParse("DA66737E-1ED4-4DDF-B98C-70CEBFE3ADA0")),
 				)))
 				require.NoError(t, allocateError(table.AllocatePartition(1*GiB, "1G2", partType1)))
-				require.NoError(t, allocateError(table.AllocatePartition(1*GiB, "1G3", partType2,
+				require.NoError(t, allocateError(table.AllocatePartition(1*GiB, "1G3", partType1)))
+				require.NoError(t, allocateError(table.AllocatePartition(1*GiB, "1G4", partType2,
 					gpt.WithUniqueGUID(uuid.MustParse("3D0FE86B-7791-4659-B564-FC49A542866D")),
 				)))
 
 				require.NoError(t, table.DeletePartition(1))
+				require.NoError(t, table.DeletePartition(2))
 
-				// allocate smaller partitions to fill the gap
+				// gap is 2 GiB, while the tail available space is < 2 GiB, so small partitions will be appended to the end
 				require.NoError(t, allocateError(table.AllocatePartition(200*MiB, "200M", partType2,
 					gpt.WithUniqueGUID(uuid.MustParse("EE1A711E-DE12-4D9F-98FF-672F7AD638F8")),
 				)))
 				require.NoError(t, allocateError(table.AllocatePartition(400*MiB, "400M", partType2,
 					gpt.WithUniqueGUID(uuid.MustParse("15E609C8-9775-4E86-AF59-8A87E7C03FAB")),
 				)))
 
-				// partition that doesn't fit the gap will be appended to the end
-				require.NoError(t, allocateError(table.AllocatePartition(500*MiB, "500M", partType2,
+				// bigger partition will fill the gap
+				require.NoError(t, allocateError(table.AllocatePartition(1500*MiB, "1500M", partType2,
 					gpt.WithUniqueGUID(uuid.MustParse("15E609C8-9775-4E86-AF59-8A87E7C03FAC")),
 				)))
 			},

diff --git a/partitioning/gpt/testdata/mix-allocate.gdisk b/partitioning/gpt/testdata/mix-allocate.gdisk
@@ -12,11 +12,11 @@ Partition table holds up to 128 entries
 Main partition table begins at sector 2 and ends at sector 33
 First usable sector is 2048, last usable sector is 12582878
 Partitions will be aligned on 2048-sector boundaries
-Total free space is 6133727 sectors (2.9 GiB)
+Total free space is 4085727 sectors (1.9 GiB)
 
 Number  Start (sector)    End (sector)  Size       Code  Name
    1            2048         2099199   1024.0 MiB  EF00  1G1
-   2         2099200         2508799   200.0 MiB   8E00  200M
-   3         2508800         3327999   400.0 MiB   8E00  400M
-   4         4196352         6293503   1024.0 MiB  8E00  1G3
-   5         6293504         7317503   500.0 MiB   8E00  500M
+   3         2099200         5171199   1.5 GiB     8E00  1500M
+   4         6293504         8390655   1024.0 MiB  8E00  1G4
+   5         8390656         8800255   200.0 MiB   8E00  200M
+   6         8800256         9619455   400.0 MiB   8E00  400M
diff --git a/partitioning/gpt/testdata/mix-allocate.sfdisk b/partitioning/gpt/testdata/mix-allocate.sfdisk
@@ -6,7 +6,7 @@ last-lba: 12582878
 sector-size: 512
 
 start=        2048, size=     2097152, type=C12A7328-F81F-11D2-BA4B-00A0C93EC93B, uuid=DA66737E-1ED4-4DDF-B98C-70CEBFE3ADA0, name="1G1"
-start=     2099200, size=      409600, type=E6D6D379-F507-44C2-A23C-238F2A3DF928, uuid=EE1A711E-DE12-4D9F-98FF-672F7AD638F8, name="200M"
-start=     2508800, size=      819200, type=E6D6D379-F507-44C2-A23C-238F2A3DF928, uuid=15E609C8-9775-4E86-AF59-8A87E7C03FAB, name="400M"
-start=     4196352, size=     2097152, type=E6D6D379-F507-44C2-A23C-238F2A3DF928, uuid=3D0FE86B-7791-4659-B564-FC49A542866D, name="1G3"
-start=     6293504, size=     1024000, type=E6D6D379-F507-44C2-A23C-238F2A3DF928, uuid=15E609C8-9775-4E86-AF59-8A87E7C03FAC, name="500M"
+start=     2099200, size=     3072000, type=E6D6D379-F507-44C2-A23C-238F2A3DF928, uuid=15E609C8-9775-4E86-AF59-8A87E7C03FAC, name="1500M"
+start=     6293504, size=     2097152, type=E6D6D379-F507-44C2-A23C-238F2A3DF928, uuid=3D0FE86B-7791-4659-B564-FC49A542866D, name="1G4"
+start=     8390656, size=      409600, type=E6D6D379-F507-44C2-A23C-238F2A3DF928, uuid=EE1A711E-DE12-4D9F-98FF-672F7AD638F8, name="200M"
+start=     8800256, size=      819200, type=E6D6D379-F507-44C2-A23C-238F2A3DF928, uuid=15E609C8-9775-4E86-AF59-8A87E7C03FAB, name="400M"