Changes in uspace/lib/ext4/libext4_filesystem.c [eb94d84:c1fd281] in mainline

File:

• uspace/lib/ext4/libext4_filesystem.c (modified) (6 diffs)

uspace/lib/ext4/libext4_filesystem.c

@@ -40 +40 @@
 #include <malloc.h>
 #include <ipc/vfs.h>
+#include <align.h>
 #include "libext4.h"
 
@@ -250 +251 @@
 }
 
+/** Convert the absolute block number to group number
+ *
+ * @param sb    Pointer to the superblock
+ * @param b     Absolute block number
+ *
+ * @return      Group number
+ */
+uint32_t ext4_filesystem_blockaddr2group(ext4_superblock_t *sb, uint64_t b)
+{
+        uint32_t blocks_per_group = ext4_superblock_get_blocks_per_group(sb);
+        uint32_t first_block = ext4_superblock_get_first_data_block(sb);
+
+        return (b - first_block) / blocks_per_group;
+}
+
 /** Initialize block bitmap in block group.
  *
@@ -259 +275 @@
 static int ext4_filesystem_init_block_bitmap(ext4_block_group_ref_t *bg_ref)
 {
+        uint64_t itb;
+        uint32_t sz;
+        uint32_t i;
+
         /* Load bitmap */
-        uint32_t bitmap_block_addr = ext4_block_group_get_block_bitmap(
+        ext4_superblock_t *sb = bg_ref->fs->superblock;
+        uint64_t bitmap_block_addr = ext4_block_group_get_block_bitmap(
+            bg_ref->block_group, bg_ref->fs->superblock);
+        uint64_t bitmap_inode_addr = ext4_block_group_get_inode_bitmap(
             bg_ref->block_group, bg_ref->fs->superblock);
         
@@ -272 +295 @@
         
         /* Initialize all bitmap bits to zero */
-        uint32_t block_size = ext4_superblock_get_block_size(bg_ref->fs->superblock);
+        uint32_t block_size = ext4_superblock_get_block_size(sb);
         memset(bitmap, 0, block_size);
         
-        /* Determine first block and first data block in group */
-        uint32_t first_idx = 0;
-        
-        uint32_t first_data = ext4_balloc_get_first_data_block_in_group(
-            bg_ref->fs->superblock, bg_ref);
-        uint32_t first_data_idx = ext4_filesystem_blockaddr2_index_in_group(
-            bg_ref->fs->superblock, first_data);
-        
+        /* Determine the number of reserved blocks in the group */
+        uint32_t reserved_cnt = ext4_filesystem_bg_get_backup_blocks(bg_ref);
+
         /* Set bits from to first block to first data block - 1 to one (allocated) */
-        for (uint32_t block = first_idx; block < first_data_idx; ++block)
+        for (uint32_t block = 0; block < reserved_cnt; ++block)
                 ext4_bitmap_set_bit(bitmap, block);
-        
+
+        uint32_t bitmap_block_gid = ext4_filesystem_blockaddr2group(sb,
+            bitmap_block_addr);
+        if (bitmap_block_gid == bg_ref->index) {
+                ext4_bitmap_set_bit(bitmap,
+                    ext4_filesystem_blockaddr2_index_in_group(sb, bitmap_block_addr));
+        }
+
+        uint32_t bitmap_inode_gid = ext4_filesystem_blockaddr2group(sb,
+            bitmap_inode_addr);
+        if (bitmap_inode_gid == bg_ref->index) {
+                ext4_bitmap_set_bit(bitmap,
+                    ext4_filesystem_blockaddr2_index_in_group(sb, bitmap_inode_addr));
+        }
+
+        itb = ext4_block_group_get_inode_table_first_block(bg_ref->block_group,
+            sb);
+        sz = ext4_filesystem_bg_get_itable_size(sb, bg_ref);
+
+        for (i = 0; i < sz; ++i, ++itb) {
+                uint32_t gid = ext4_filesystem_blockaddr2group(sb, itb);
+                if (gid == bg_ref->index) {
+                        ext4_bitmap_set_bit(bitmap,
+                            ext4_filesystem_blockaddr2_index_in_group(sb, itb));
+                }
+        }
+
         bitmap_block->dirty = true;
         
@@ -423 +467 @@
         }
         
-        /* Inititialize in-memory representation */
+        /* Initialize in-memory representation */
         newref->block_group = newref->block->data + offset;
         newref->fs = fs;
@@ -523 +567 @@
 }
 
+/** Get the size of the block group's inode table
+ *
+ * @param sb     Pointer to the superblock
+ * @param bg_ref Pointer to the block group reference
+ *
+ * @return       Size of the inode table in blocks.
+ */
+uint32_t ext4_filesystem_bg_get_itable_size(ext4_superblock_t *sb,
+    ext4_block_group_ref_t *bg_ref)
+{
+        uint32_t itable_size;
+        uint32_t block_group_count = ext4_superblock_get_block_group_count(sb);
+        uint16_t inode_table_item_size = ext4_superblock_get_inode_size(sb);
+        uint32_t inodes_per_group = ext4_superblock_get_inodes_per_group(sb);
+        uint32_t block_size = ext4_superblock_get_block_size(sb);
+
+        if (bg_ref->index < block_group_count - 1) {
+                itable_size = inodes_per_group * inode_table_item_size;
+        } else {
+                /* Last block group could be smaller */
+                uint32_t inodes_count_total = ext4_superblock_get_inodes_count(sb);
+                itable_size =
+                    (inodes_count_total - ((block_group_count - 1) * inodes_per_group)) *
+                    inode_table_item_size;
+        }
+
+        return ROUND_UP(itable_size, block_size) / block_size;
+}
+
+/* Check if n is a power of p */
+static bool is_power_of(uint32_t n, unsigned p)
+{
+        if (p == 1 && n != p)
+                return false;
+
+        while (n != p) {
+                if (n < p)
+                        return false;
+                else if ((n % p) != 0)
+                        return false;
+
+                n /= p;
+        }
+
+        return true;
+}
+
+/** Get the number of blocks used by superblock + gdt + reserved gdt backups
+ *
+ * @param bg    Pointer to block group
+ *
+ * @return      Number of blocks
+ */
+uint32_t ext4_filesystem_bg_get_backup_blocks(ext4_block_group_ref_t *bg)
+{
+        uint32_t const idx = bg->index;
+        uint32_t r = 0;
+        bool has_backups = false;
+        ext4_superblock_t *sb = bg->fs->superblock;
+
+        /* First step: determine if the block group contains the backups */
+
+        if (idx <= 1)
+                has_backups = true;
+        else {
+                if (ext4_superblock_has_feature_compatible(sb,
+                    EXT4_FEATURE_COMPAT_SPARSE_SUPER2)) {
+                        uint32_t g1, g2;
+
+                        ext4_superblock_get_backup_groups_sparse2(sb,
+                            &g1, &g2);
+
+                        if (idx == g1 || idx == g2)
+                                has_backups = true;
+                } else if (!ext4_superblock_has_feature_read_only(sb,
+                    EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER)) {
+                        /* Very old fs were all block groups have
+                         * superblock and block descriptors backups.
+                         */
+                        has_backups = true;
+                } else {
+                        if ((idx & 1) && (is_power_of(idx, 3) ||
+                            is_power_of(idx, 5) || is_power_of(idx, 7)))
+                                has_backups = true;
+                }
+        }
+
+        if (has_backups) {
+                uint32_t bg_count;
+                uint32_t bg_desc_sz;
+                uint32_t gdt_table; /* Size of the GDT in blocks */
+                uint32_t block_size = ext4_superblock_get_block_size(sb);
+
+                /* Now we know that this block group has backups,
+                 * we have to compute how many blocks are reserved
+                 * for them
+                 */
+
+                if (idx == 0 && block_size == 1024) {
+                        /* Special case for first group were the boot block
+                         * resides
+                         */
+                        r++;
+                }
+
+                /* This accounts for the superblock */
+                r++;
+
+                /* Add the number of blocks used for the GDT */
+                bg_count = ext4_superblock_get_block_group_count(sb);
+                bg_desc_sz = ext4_superblock_get_desc_size(sb);
+                gdt_table = ROUND_UP(bg_count * bg_desc_sz, block_size) /
+                    block_size;
+
+                r += gdt_table;
+
+                /* And now the number of reserved GDT blocks */
+                r += ext4_superblock_get_reserved_gdt_blocks(sb);
+        }
+
+        return r;
+}
+
 /** Put reference to block group.
  *
- * @oaram ref Pointer for reference to be put back
+ * @param ref Pointer for reference to be put back
  *
  * @return Error code