Changeset 3711e7e in mainline for uspace/lib/ext4/libext4_filesystem.c

Timestamp:

2011-10-05T09:35:12Z (13 years ago)

Author:

Frantisek Princ <frantisek.princ@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

3712434

Parents:

cfa1a8a

Message:

Complete mounting skeleton (ported from ext2fs) - some filesystem checks during mount process still missing

File:

• uspace/lib/ext4/libext4_filesystem.c (modified) (3 diffs)

uspace/lib/ext4/libext4_filesystem.c

@@ -38 +38 @@
 #include <errno.h>
 #include <malloc.h>
-#include "libext4_filesystem.h"
+#include "libext4.h"
 
 /**
@@ -83 +83 @@
 
         return EOK;
+}
+
+/**
+ * TODO doxy
+ */
+void ext4_filesystem_fini(ext4_filesystem_t *fs)
+{
+        free(fs->superblock);
+        block_fini(fs->device);
 }
 
@@ -132 +141 @@
  * TODO doxy
  */
-void ext4_filesystem_fini(ext4_filesystem_t *fs)
-{
-        free(fs->superblock);
-        block_fini(fs->device);
-}
-
+int ext4_filesystem_get_block_group_ref(ext4_filesystem_t *fs, uint32_t bgid,
+    ext4_block_group_ref_t **ref)
+{
+        int rc;
+        aoff64_t block_id;
+        uint32_t descriptors_per_block;
+        size_t offset;
+        ext4_block_group_ref_t *newref;
+
+        newref = malloc(sizeof(ext4_block_group_ref_t));
+        if (newref == NULL) {
+                return ENOMEM;
+        }
+
+        descriptors_per_block = ext4_superblock_get_block_size(fs->superblock)
+            / EXT4_BLOCK_GROUP_DESCRIPTOR_SIZE;
+
+        /* Block group descriptor table starts at the next block after superblock */
+        block_id = ext4_superblock_get_first_block(fs->superblock) + 1;
+
+        /* Find the block containing the descriptor we are looking for */
+        block_id += bgid / descriptors_per_block;
+        offset = (bgid % descriptors_per_block) * EXT4_BLOCK_GROUP_DESCRIPTOR_SIZE;
+
+        rc = block_get(&newref->block, fs->device, block_id, 0);
+        if (rc != EOK) {
+                free(newref);
+                return rc;
+        }
+
+        newref->block_group = newref->block->data + offset;
+
+        *ref = newref;
+
+        return EOK;
+}
+
+/**
+ * TODO doxy
+ */
+int ext4_filesystem_get_inode_ref(ext4_filesystem_t *fs, uint32_t index,
+    ext4_inode_ref_t **ref)
+{
+        int rc;
+        aoff64_t block_id;
+        uint32_t block_group;
+        uint32_t offset_in_group;
+        uint32_t byte_offset_in_group;
+        size_t offset_in_block;
+        uint32_t inodes_per_group;
+        uint32_t inode_table_start;
+        uint16_t inode_size;
+        uint32_t block_size;
+        ext4_block_group_ref_t *bg_ref;
+        ext4_inode_ref_t *newref;
+
+        newref = malloc(sizeof(ext4_inode_ref_t));
+        if (newref == NULL) {
+                return ENOMEM;
+        }
+
+        inodes_per_group = ext4_superblock_get_inodes_per_group(fs->superblock);
+
+        /* inode numbers are 1-based, but it is simpler to work with 0-based
+         * when computing indices
+         */
+        index -= 1;
+        block_group = index / inodes_per_group;
+        offset_in_group = index % inodes_per_group;
+
+        rc = ext4_filesystem_get_block_group_ref(fs, block_group, &bg_ref);
+        if (rc != EOK) {
+                free(newref);
+                return rc;
+        }
+
+        inode_table_start = ext4_block_group_get_inode_table_first_block(
+            bg_ref->block_group);
+
+        inode_size = ext4_superblock_get_inode_size(fs->superblock);
+        block_size = ext4_superblock_get_block_size(fs->superblock);
+
+        byte_offset_in_group = offset_in_group * inode_size;
+
+        block_id = inode_table_start + (byte_offset_in_group / block_size);
+        offset_in_block = byte_offset_in_group % block_size;
+
+        rc = block_get(&newref->block, fs->device, block_id, 0);
+        if (rc != EOK) {
+                free(newref);
+                return rc;
+        }
+
+        newref->inode = newref->block->data + offset_in_block;
+        /* we decremented index above, but need to store the original value
+         * in the reference
+         */
+        newref->index = index+1;
+
+        *ref = newref;
+
+        return EOK;
+}
 
 /**