libblkid: bcachefs: add crc32 checksum support

Signed-off-by: Thomas Weißschuh <thomas@t-8ch.de>

diff --git a/libblkid/src/superblocks/bcache.c b/libblkid/src/superblocks/bcache.c
index 323e0f0106ec6a1874a38f28b0b7ff60a4090fa0..83c9ba276b7e81641f5b812c74e16232d8cb5d92 100644 (file)
--- a/libblkid/src/superblocks/bcache.c
+++ b/libblkid/src/superblocks/bcache.c
@@ -12,6 +12,7 @@
 #include <stdio.h>
 
 #include "superblocks.h"
+#include "crc32c.h"
 #include "crc64.h"
 
 #define SB_LABEL_SIZE      32
@@ -48,8 +49,18 @@ struct bcachefs_sb_field_members {
        struct bcachefs_sb_member       members[];
 }  __attribute__((packed));
 
+enum bcachefs_sb_csum_type {
+       BCACHEFS_SB_CSUM_TYPE_NONE = 0,
+       BCACHEFS_SB_CSUM_TYPE_CRC32C = 1,
+};
+
+union bcachefs_sb_csum {
+       uint32_t crc32c;
+       uint8_t raw[16];
+} __attribute__((packed));
+
 struct bcachefs_super_block {
-       uint8_t         csum[16];
+       union bcachefs_sb_csum  csum;
        uint16_t        version;
        uint16_t        version_min;
        uint16_t        pad[2];
@@ -158,17 +169,10 @@ static void probe_bcachefs_sb_members(blkid_probe pr,
        blkid_probe_set_fssize(pr, sectors * BCACHEFS_SECTOR_SIZE);
 }
 
-static void probe_bcachefs_sb_fields(blkid_probe pr, const struct blkid_idmag *mag,
-                                    const struct bcachefs_super_block *bcs)
+static void probe_bcachefs_sb_fields(blkid_probe pr, const struct bcachefs_super_block *bcs,
+                                    unsigned char *sb_start, unsigned char *sb_end)
 {
-       unsigned long sb_size = BCACHEFS_SB_FIELDS_OFF + BYTES(bcs);
-       unsigned char *sb = blkid_probe_get_sb_buffer(pr, mag, sb_size);
-
-       if (!sb)
-               return;
-
-       unsigned char *sb_end = sb + sb_size;
-       unsigned char *field_addr = sb + BCACHEFS_SB_FIELDS_OFF;
+       unsigned char *field_addr = sb_start + BCACHEFS_SB_FIELDS_OFF;
 
        while (1) {
                struct bcachefs_sb_field *field = (struct bcachefs_sb_field *) field_addr;
@@ -188,6 +192,44 @@ static void probe_bcachefs_sb_fields(blkid_probe pr, const struct blkid_idmag *m
        }
 }
 
+static int bcachefs_validate_checksum(blkid_probe pr, const struct bcachefs_super_block *bcs,
+                                     unsigned char *sb, unsigned char *sb_end)
+{
+       uint8_t checksum_type = be64_to_cpu(bcs->flags[0]) >> 58;
+       unsigned char *checksummed_data_start = sb + sizeof(bcs->csum);
+       size_t checksummed_data_size = sb_end - checksummed_data_start;
+       switch (checksum_type) {
+               case BCACHEFS_SB_CSUM_TYPE_NONE:
+                       return 1;
+               case BCACHEFS_SB_CSUM_TYPE_CRC32C: {
+                       uint32_t crc = crc32c(~0LL, checksummed_data_start, checksummed_data_size) ^ ~0LL;
+                       return blkid_probe_verify_csum(pr, crc, le32_to_cpu(bcs->csum.crc32c));
+               }
+               default:
+                       DBG(LOWPROBE, ul_debug("bcachefs: unknown checksum type %d, ignoring.", checksum_type));
+                       return 1;
+       }
+}
+
+static int probe_bcachefs_full_sb(blkid_probe pr, const struct blkid_idmag *mag,
+               const struct bcachefs_super_block *bcs)
+{
+       unsigned long sb_size = BCACHEFS_SB_FIELDS_OFF + BYTES(bcs);
+       unsigned char *sb = blkid_probe_get_sb_buffer(pr, mag, sb_size);
+
+       if (!sb)
+               return BLKID_PROBE_NONE;
+
+       unsigned char *sb_end = sb + sb_size;
+
+       if (!bcachefs_validate_checksum(pr, bcs, sb, sb_end))
+               return BLKID_PROBE_NONE;
+
+       probe_bcachefs_sb_fields(pr, bcs, sb, sb_end);
+       return BLKID_PROBE_OK;
+}
+
+
 static int probe_bcachefs(blkid_probe pr, const struct blkid_idmag *mag)
 {
        struct bcachefs_super_block *bcs;
@@ -210,9 +252,7 @@ static int probe_bcachefs(blkid_probe pr, const struct blkid_idmag *mag)
        blkid_probe_set_block_size(pr, blocksize * BCACHEFS_SECTOR_SIZE);
        blkid_probe_set_fsblocksize(pr, blocksize * BCACHEFS_SECTOR_SIZE);
        blkid_probe_set_wiper(pr, 0, BCACHE_SB_OFF);
-       probe_bcachefs_sb_fields(pr, mag, bcs);
-
-       return BLKID_PROBE_OK;
+       return probe_bcachefs_full_sb(pr, mag, bcs);
 }
 
 const struct blkid_idinfo bcache_idinfo =