diff options
| -rw-r--r-- | fs/ext4/mballoc.c | 49 |
1 files changed, 32 insertions, 17 deletions
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c index 194a9f995c36..65335248825c 100644 --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -682,6 +682,24 @@ do { \ } \ } while (0) +/* + * Perform buddy integrity check with the following steps: + * + * 1. Top-down validation (from highest order down to order 1, excluding order-0 bitmap): + * For each pair of adjacent orders, if a higher-order bit is set (indicating a free block), + * at most one of the two corresponding lower-order bits may be clear (free). + * + * 2. Order-0 (bitmap) validation, performed on bit pairs: + * - If either bit in a pair is set (1, allocated), then all corresponding higher-order bits + * must not be free (0). + * - If both bits in a pair are clear (0, free), then exactly one of the corresponding + * higher-order bits must be free (0). + * + * 3. Preallocation (pa) list validation: + * For each preallocated block (pa) in the group: + * - Verify that pa_pstart falls within the bounds of this block group. + * - Ensure the corresponding bit(s) in the order-0 bitmap are marked as allocated (1). + */ static void __mb_check_buddy(struct ext4_buddy *e4b, char *file, const char *function, int line) { @@ -723,15 +741,6 @@ static void __mb_check_buddy(struct ext4_buddy *e4b, char *file, continue; } - /* both bits in buddy2 must be 1 */ - MB_CHECK_ASSERT(mb_test_bit(i << 1, buddy2)); - MB_CHECK_ASSERT(mb_test_bit((i << 1) + 1, buddy2)); - - for (j = 0; j < (1 << order); j++) { - k = (i * (1 << order)) + j; - MB_CHECK_ASSERT( - !mb_test_bit(k, e4b->bd_bitmap)); - } count++; } MB_CHECK_ASSERT(e4b->bd_info->bb_counters[order] == count); @@ -747,15 +756,21 @@ static void __mb_check_buddy(struct ext4_buddy *e4b, char *file, fragments++; fstart = i; } - continue; + } else { + fstart = -1; } - fstart = -1; - /* check used bits only */ - for (j = 0; j < e4b->bd_blkbits + 1; j++) { - buddy2 = mb_find_buddy(e4b, j, &max2); - k = i >> j; - MB_CHECK_ASSERT(k < max2); - MB_CHECK_ASSERT(mb_test_bit(k, buddy2)); + if (!(i & 1)) { + int in_use, zero_bit_count = 0; + + in_use = mb_test_bit(i, buddy) || mb_test_bit(i + 1, buddy); + for (j = 1; j < e4b->bd_blkbits + 2; j++) { + buddy2 = mb_find_buddy(e4b, j, &max2); + k = i >> j; + MB_CHECK_ASSERT(k < max2); + if (!mb_test_bit(k, buddy2)) + zero_bit_count++; + } + MB_CHECK_ASSERT(zero_bit_count == !in_use); } } MB_CHECK_ASSERT(!EXT4_MB_GRP_NEED_INIT(e4b->bd_info)); |