Changeset ea50e671 in mainline for uspace/lib/ext4/src/superblock.c

Timestamp:

2025-01-29T13:51:25Z (3 weeks ago)

Author:

Jiří Zárevúcky <zarevucky.jiri@…>

Children:

4a3a5a0

Parents:

cb747b3

Message:

A few adjustments

File:

• uspace/lib/ext4/src/superblock.c (modified) (2 diffs)

uspace/lib/ext4/src/superblock.c

@@ -1206 +1206 @@
 errno_t ext4_superblock_write_direct(service_id_t service_id, ext4_superblock_t *sb)
 {
-        void *tmp_sb = sb;
-
         /* Load physical block size from block device */
         size_t phys_block_size;
@@ -1217 +1215 @@
         uint64_t first_block = EXT4_SUPERBLOCK_OFFSET / phys_block_size;
 
-        /* Compute number of block to write */
-        size_t block_count;
         if (phys_block_size <= EXT4_SUPERBLOCK_SIZE) {
-                block_count = EXT4_SUPERBLOCK_SIZE / phys_block_size;
-                /* Check alignment */
-                if (EXT4_SUPERBLOCK_SIZE % phys_block_size)
-                        block_count++;
-        } else {
-                block_count = 1;
-                tmp_sb = malloc(phys_block_size);
-                if (tmp_sb == NULL)
-                        return ENOMEM;
-                /* Preserve block data */
-                rc = block_read_direct(service_id, first_block, 1, tmp_sb);
-                if (rc != EOK) {
-                        free(tmp_sb);
-                        return rc;
-                }
-                void *sb_pos = (uint8_t *)tmp_sb + EXT4_SUPERBLOCK_OFFSET;
-                memcpy(sb_pos, sb, EXT4_SUPERBLOCK_SIZE);
+                /* Superblock is a multiple of physical block sizes */
+                size_t block_count = EXT4_SUPERBLOCK_SIZE / phys_block_size;
+                return block_write_direct(service_id, first_block, block_count, sb);
         }
 
-        /* Write data */
-        rc = block_write_direct(service_id, first_block, block_count, tmp_sb);
-
-        if (phys_block_size > EXT4_SUPERBLOCK_SIZE)
+        /*
+         * Superblock fills only a part of the physical block,
+         * but we can only overwrite an entire physical block.
+         */
+        void *tmp_sb = malloc(phys_block_size);
+        if (tmp_sb == NULL)
+                return ENOMEM;
+
+        /* Preserve physical block data */
+        rc = block_read_direct(service_id, first_block, 1, tmp_sb);
+        if (rc != EOK) {
                 free(tmp_sb);
+                return rc;
+        }
+
+        /* Write the superblock */
+        void *sb_pos = tmp_sb + EXT4_SUPERBLOCK_OFFSET % phys_block_size;
+        memcpy(sb_pos, sb, EXT4_SUPERBLOCK_SIZE);
+
+        /* Write physical block to device */
+        rc = block_write_direct(service_id, first_block, 1, tmp_sb);
+        free(tmp_sb);
         return rc;
 }