Changeset 81a7858 in mainline

Timestamp:

2012-05-10T08:47:06Z (12 years ago)

Author:

Frantisek Princ <frantisek.princ@…>

Branches:

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

Children:

f2eece1

Parents:

bed78cb

Message:

more comments, now missing very small number of comments

Location:

uspace

Files:

• lib/ext4/libext4_block_group.c (modified) (1 diff)
• lib/ext4/libext4_extent.c (modified) (10 diffs)
• lib/ext4/libext4_filesystem.c (modified) (40 diffs)
• srv/fs/ext4fs/ext4fs_ops.c (modified) (1 diff)

uspace/lib/ext4/libext4_block_group.c

@@ -33 +33 @@
 /**
  * @file        libext4_block_group.c
- * @brief       Ext4 block group structure operations
+ * @brief       Ext4 block group structure operations.
  */
 

uspace/lib/ext4/libext4_extent.c

@@ -933 +933 @@
 }
 
-/** TODO comment
- *
+/** Append data block to the i-node.
+ *
+ * This function allocates data block, tries to append it
+ * to some existing extent or creates new extents.
+ * It includes possible extent tree modifications (splitting).
+ *
+ * @param inode_ref                     i-node to append block to
+ * @param iblock                        output logical number of newly allocated block
+ * @param fblock                        output physical block address of newly allocated block
+ * @return                                      error code
  */
 int ext4_extent_append_block(ext4_inode_ref_t *inode_ref,
@@ -968 +976 @@
         }
 
-        // Add new extent to the node
+        // Add new extent to the node if not present
         if (path_ptr->extent == NULL) {
                 goto append_extent;
@@ -979 +987 @@
         if (block_count < block_limit) {
 
+                // There is space for new block in the extent
+
                 if (block_count == 0) {
+
+                        // Existing extent is empty
 
                         rc = ext4_balloc_alloc_block(inode_ref, &phys_block);
@@ -986 +998 @@
                         }
 
+                        // Initialize extent
                         ext4_extent_set_first_block(path_ptr->extent, new_block_idx);
                         ext4_extent_set_start(path_ptr->extent, phys_block);
                         ext4_extent_set_block_count(path_ptr->extent, 1);
 
+                        // Update i-node
                         ext4_inode_set_size(inode_ref->inode, inode_size + block_size);
                         inode_ref->dirty = true;
@@ -998 +1012 @@
                 } else {
 
+                        // Existing extent contains some blocks
+
                         phys_block = ext4_extent_get_start(path_ptr->extent);
                         phys_block += ext4_extent_get_block_count(path_ptr->extent);
 
+                        // Check if the following block is free for allocation
                         bool free;
                         rc = ext4_balloc_try_alloc_block(inode_ref, phys_block, &free);
@@ -1008 +1025 @@
 
                         if (! free) {
-                                // target is not free
+                                // target is not free, new block must be appended to new extent
                                 goto append_extent;
                         }
 
 
+                        // Update extent
                         ext4_extent_set_block_count(path_ptr->extent, block_count + 1);
 
+                        // Update i-node
                         ext4_inode_set_size(inode_ref->inode, inode_size + block_size);
                         inode_ref->dirty = true;
@@ -1024 +1043 @@
         }
 
+// Append new extent to the tree
 append_extent:
 
         phys_block = 0;
-        // Allocate and insert insert new block
+
+        // Allocate new data block
         rc = ext4_balloc_alloc_block(inode_ref, &phys_block);
         if (rc != EOK) {
@@ -1034 +1055 @@
         }
 
+        // Append extent for new block (includes tree splitting if needed)
         rc = ext4_extent_append_extent(inode_ref, path, &path_ptr, new_block_idx);
         if (rc != EOK) {
@@ -1040 +1062 @@
         }
 
+        // Initialize newly created extent
         ext4_extent_set_block_count(path_ptr->extent, 1);
         ext4_extent_set_first_block(path_ptr->extent, new_block_idx);
         ext4_extent_set_start(path_ptr->extent, phys_block);
 
+        // Update i-node
         ext4_inode_set_size(inode_ref->inode, inode_size + block_size);
         inode_ref->dirty = true;
@@ -1049 +1073 @@
         path_ptr->block->dirty = true;
 
+
 finish:
-
+        // Set return values
         *iblock = new_block_idx;
         *fblock = phys_block;

uspace/lib/ext4/libext4_filesystem.c

@@ -186 +186 @@
  * @param fs            filesystem to find block group on
  * @param bgid          index of block group to load
- * @oaram ref           output pointer for reference
+ * @param ref           output pointer for reference
  * @return                      error code
  */
@@ -229 +229 @@
 }
 
-/** TODO comment
- *
+/** Compute checksum of block group descriptor.
+ *
+ * It uses crc functions from Linux kernel implementation.
+ *
+ * @param sb            superblock
+ * @param bgid          index of block group in the filesystem
+ * @param bg            block group to compute checksum for
+ * @return                      checksum value
  */
 static uint16_t ext4_filesystem_bg_checksum(ext4_superblock_t *sb, uint32_t bgid,
                             ext4_block_group_t *bg)
 {
+        // If checksum not supported, 0 will be returned
         uint16_t crc = 0;
 
+        // Compute the checksum only if the filesystem supports it
         if (ext4_superblock_has_feature_read_only(sb, EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) {
 
@@ -244 +252 @@
                 uint32_t offset = (uint32_t)(checksum - base);
 
+                // Convert block group index to little endian
                 uint32_t le_group = host2uint32_t_le(bgid);
 
+                // Initialization
                 crc = crc16(~0, sb->uuid, sizeof(sb->uuid));
+
+                // Include index of block group
                 crc = crc16(crc, (uint8_t *)&le_group, sizeof(le_group));
+
+                // Compute crc from the first part (stop before checksum field)
                 crc = crc16(crc, (uint8_t *)bg, offset);
 
-                offset += sizeof(bg->checksum); /* skip checksum */
-
-                /* for checksum of struct ext4_group_desc do the rest...*/
+                // Skip checksum
+                offset += sizeof(bg->checksum);
+
+                // Checksum of the rest of block group descriptor
                 if ((ext4_superblock_has_feature_incompatible(sb, EXT4_FEATURE_INCOMPAT_64BIT)) &&
                         offset < ext4_superblock_get_desc_size(sb)) {
@@ -368 +383 @@
 }
 
-/** TODO comment
- *
+/** Put reference to i-node.
+ *
+ * @param ref           pointer for reference to be put back
+ * @return                      error code
  */
 int ext4_filesystem_put_inode_ref(ext4_inode_ref_t *ref)
@@ -375 +392 @@
         int rc;
 
+        // Check if reference modified
         if (ref->dirty) {
+
+                // Mark block dirty for writing changes to physical device
                 ref->block->dirty = true;
         }
 
+        // Put back block, that contains i-node
         rc = block_put(ref->block);
         free(ref);
@@ -385 +406 @@
 }
 
-/** TODO comment
- *
+/** Allocate new i-node in the filesystem.
+ *
+ * @param fs                    filesystem to allocated i-node on
+ * @param inode_ref             output pointer to return reference to allocated i-node
+ * @param flags                 flags to be set for newly created i-node
+ * @return                              error code
  */
 int ext4_filesystem_alloc_inode(ext4_filesystem_t *fs,
@@ -393 +418 @@
         int rc;
 
+        // Check if newly allocated i-node will be a directory
         bool is_dir = false;
         if (flags & L_DIRECTORY) {
@@ -398 +424 @@
         }
 
-        // allocate inode
+        // Allocate inode by allocation algorithm
         uint32_t index;
         rc = ext4_ialloc_alloc_inode(fs, &index, is_dir);
@@ -405 +431 @@
         }
 
+        // Load i-node from on-disk i-node table
         rc = ext4_filesystem_get_inode_ref(fs, index, inode_ref);
         if (rc != EOK) {
@@ -411 +438 @@
         }
 
-        // init inode
+        // Initialize i-node
         ext4_inode_t *inode = (*inode_ref)->inode;
 
@@ -438 +465 @@
         }
 
+        // Initialize extents if needed
         if (ext4_superblock_has_feature_incompatible(
                         fs->superblock, EXT4_FEATURE_INCOMPAT_EXTENTS)) {
@@ -461 +489 @@
 }
 
-/** TODO comment
- *
+/** Release i-node and mark it as free.
+ *
+ * @param inode_ref                     i-node to be released
+ * @return                                      error code
  */
 int ext4_filesystem_free_inode(ext4_inode_ref_t *inode_ref)
@@ -470 +500 @@
         ext4_filesystem_t *fs = inode_ref->fs;
 
+        // For extents must be data block destroyed by other way
         if (ext4_superblock_has_feature_incompatible(
                         fs->superblock, EXT4_FEATURE_INCOMPAT_EXTENTS) &&
@@ -478 +509 @@
         }
 
-        // release all indirect (no data) blocks
+        // Release all indirect (no data) blocks
 
         // 1) Single indirect
@@ -583 +614 @@
 
 finish:
+
+        // Mark inode dirty for writing to the physical device
         inode_ref->dirty = true;
 
-        // Free inode
+        // Free inode by allocator
         if (ext4_inode_is_type(fs->superblock, inode_ref->inode,
                         EXT4_INODE_MODE_DIRECTORY)) {
@@ -599 +632 @@
 }
 
-/** TODO comment
- *
+/** Truncate i-node data blocks.
+ *
+ * @param inode_ref             i-node to be truncated
+ * @param new_size              new size of inode (must be < current size)
+ * @return                              error code
  */
 int ext4_filesystem_truncate_inode(
@@ -609 +645 @@
         ext4_superblock_t *sb = inode_ref->fs->superblock;
 
+        // Check flags, if i-node can be truncated
         if (! ext4_inode_can_truncate(sb, inode_ref->inode)) {
-                // Unable to truncate
                 return EINVAL;
         }
 
+        // If sizes are equal, nothing has to be done.
         aoff64_t old_size = ext4_inode_get_size(sb, inode_ref->inode);
         if (old_size == new_size) {
-                // Nothing to do
                 return EOK;
         }
 
-        // It's not suppported to make the larger file
+        // It's not suppported to make the larger file by truncate operation
         if (old_size < new_size) {
                 return EINVAL;
         }
 
+        // Compute how many blocks will be released
         aoff64_t size_diff = old_size - new_size;
         uint32_t block_size  = ext4_superblock_get_block_size(sb);
@@ -641 +678 @@
                                 ext4_inode_has_flag(inode_ref->inode, EXT4_INODE_FLAG_EXTENTS)) {
 
+                // Extents require special operation
+
                 rc = ext4_extent_release_blocks_from(inode_ref,
                                 old_blocks_count - diff_blocks_count);
@@ -647 +686 @@
                 }
         } else {
-                // starting from 1 because of logical blocks are numbered from 0
+
+                // Release data blocks from the end of file
+
+                // Starting from 1 because of logical blocks are numbered from 0
                 for (uint32_t i = 1; i <= diff_blocks_count; ++i) {
                         rc = ext4_filesystem_release_inode_block(inode_ref, old_blocks_count - i);
@@ -656 +698 @@
         }
 
+        // Update i-node
         ext4_inode_set_size(inode_ref->inode, new_size);
-
         inode_ref->dirty = true;
 
@@ -663 +705 @@
 }
 
-/** TODO comment
- *
+/** Get physical block address by logical index of the block.
+ *
+ * @param inode_ref             i-node to read block address from
+ * @param iblock                logical index of block
+ * @param fblock                output pointer for return physical block address
+ * @return                              error code
  */
 int ext4_filesystem_get_inode_data_block_index(ext4_inode_ref_t *inode_ref,
@@ -673 +719 @@
         ext4_filesystem_t *fs = inode_ref->fs;
 
+        // For empty file is situation simple
         if (ext4_inode_get_size(fs->superblock, inode_ref->inode) == 0) {
                 *fblock = 0;
@@ -680 +727 @@
         uint32_t current_block;
 
-        /* Handle inode using extents */
+        // Handle i-node using extents
         if (ext4_superblock_has_feature_incompatible(fs->superblock, EXT4_FEATURE_INCOMPAT_EXTENTS) &&
                         ext4_inode_has_flag(inode_ref->inode, EXT4_INODE_FLAG_EXTENTS)) {
+
                 rc = ext4_extent_find_block(inode_ref, iblock, &current_block);
 
@@ -696 +744 @@
         ext4_inode_t *inode = inode_ref->inode;
 
-        /* Handle simple case when we are dealing with direct reference */
+        // Direct block are read directly from array in i-node structure
         if (iblock < EXT4_INODE_DIRECT_BLOCK_COUNT) {
                 current_block = ext4_inode_get_direct_block(inode, (uint32_t)iblock);
                 *fblock = current_block;
+                return EOK;
+        }
+
+        // Determine indirection level of the target block
+        int level = -1;
+        for (int i = 1; i < 4; i++) {
+                if (iblock < fs->inode_block_limits[i]) {
+                        level = i;
+                        break;
+                }
+        }
+
+        if (level == -1) {
+                return EIO;
+        }
+
+        // Compute offsets for the topmost level
+        aoff64_t block_offset_in_level = iblock - fs->inode_block_limits[level-1];
+        current_block = ext4_inode_get_indirect_block(inode, level-1);
+        uint32_t offset_in_block = block_offset_in_level / fs->inode_blocks_per_level[level-1];
+
+        // Sparse file
+        if (current_block == 0) {
+                *fblock = 0;
+                return EOK;
+        }
+
+        block_t *block;
+
+        /* Navigate through other levels, until we find the block number
+         * or find null reference meaning we are dealing with sparse file
+         */
+        while (level > 0) {
+
+                // Load indirect block
+                rc = block_get(&block, fs->device, current_block, 0);
+                if (rc != EOK) {
+                        return rc;
+                }
+
+                // Read block address from indirect block
+                current_block = uint32_t_le2host(((uint32_t*)block->data)[offset_in_block]);
+
+                // Put back indirect block untouched
+                rc = block_put(block);
+                if (rc != EOK) {
+                        return rc;
+                }
+
+                // Check for sparse file
+                if (current_block == 0) {
+                        *fblock = 0;
+                        return EOK;
+                }
+
+                // Jump to the next level
+                level -= 1;
+
+                // Termination condition - we have address of data block loaded
+                if (level == 0) {
+                        break;
+                }
+
+                // Visit the next level
+                block_offset_in_level %= fs->inode_blocks_per_level[level];
+                offset_in_block = block_offset_in_level / fs->inode_blocks_per_level[level-1];
+        }
+
+        *fblock = current_block;
+
+        return EOK;
+}
+
+/** TODO comment
+ *
+ */
+int ext4_filesystem_set_inode_data_block_index(ext4_inode_ref_t *inode_ref,
+                aoff64_t iblock, uint32_t fblock)
+{
+        int rc;
+
+        ext4_filesystem_t *fs = inode_ref->fs;
+
+        /* Handle inode using extents */
+        if (ext4_superblock_has_feature_compatible(fs->superblock, EXT4_FEATURE_INCOMPAT_EXTENTS) &&
+                        ext4_inode_has_flag(inode_ref->inode, EXT4_INODE_FLAG_EXTENTS)) {
+                // not reachable !!!
+                return ENOTSUP;
+        }
+
+        /* Handle simple case when we are dealing with direct reference */
+        if (iblock < EXT4_INODE_DIRECT_BLOCK_COUNT) {
+                ext4_inode_set_direct_block(inode_ref->inode, (uint32_t)iblock, fblock);
+                inode_ref->dirty = true;
                 return EOK;
         }
@@ -716 +858 @@
         }
 
+        uint32_t block_size = ext4_superblock_get_block_size(fs->superblock);
+
         /* Compute offsets for the topmost level */
         aoff64_t block_offset_in_level = iblock - fs->inode_block_limits[level-1];
-        current_block = ext4_inode_get_indirect_block(inode, level-1);
+        uint32_t current_block = ext4_inode_get_indirect_block(inode_ref->inode, level-1);
         uint32_t offset_in_block = block_offset_in_level / fs->inode_blocks_per_level[level-1];
 
+        uint32_t new_block_addr;
+        block_t *block, *new_block;
+
         if (current_block == 0) {
-                *fblock = 0;
-                return EOK;
-        }
-
-        block_t *block;
+                rc = ext4_balloc_alloc_block(inode_ref, &new_block_addr);
+                if (rc != EOK) {
+                        return rc;
+                }
+
+                ext4_inode_set_indirect_block(inode_ref->inode, level - 1, new_block_addr);
+
+                inode_ref->dirty = true;
+
+                rc = block_get(&new_block, fs->device, new_block_addr, BLOCK_FLAGS_NOREAD);
+                if (rc != EOK) {
+                        ext4_balloc_free_block(inode_ref, new_block_addr);
+                        return rc;
+                }
+
+                memset(new_block->data, 0, block_size);
+                new_block->dirty = true;
+
+                rc = block_put(new_block);
+                if (rc != EOK) {
+                        return rc;
+                }
+
+                current_block = new_block_addr;
+        }
 
         /* Navigate through other levels, until we find the block number
@@ -732 +899 @@
          */
         while (level > 0) {
+
                 rc = block_get(&block, fs->device, current_block, 0);
                 if (rc != EOK) {
@@ -739 +907 @@
                 current_block = uint32_t_le2host(((uint32_t*)block->data)[offset_in_block]);
 
+                if ((level > 1) && (current_block == 0)) {
+                        rc = ext4_balloc_alloc_block(inode_ref, &new_block_addr);
+                        if (rc != EOK) {
+                                block_put(block);
+                                return rc;
+                        }
+
+                        rc = block_get(&new_block, fs->device, new_block_addr, BLOCK_FLAGS_NOREAD);
+                        if (rc != EOK) {
+                                block_put(block);
+                                return rc;
+                        }
+
+                        memset(new_block->data, 0, block_size);
+                        new_block->dirty = true;
+
+                        rc = block_put(new_block);
+                        if (rc != EOK) {
+                                block_put(block);
+                                return rc;
+                        }
+
+                        ((uint32_t*)block->data)[offset_in_block] = host2uint32_t_le(new_block_addr);
+                        block->dirty = true;
+                        current_block = new_block_addr;
+                }
+
+                if (level == 1) {
+                        ((uint32_t*)block->data)[offset_in_block] = host2uint32_t_le(fblock);
+                        block->dirty = true;
+                }
+
                 rc = block_put(block);
                 if (rc != EOK) {
                         return rc;
-                }
-
-                if (current_block == 0) {
-                        /* This is a sparse file */
-                        *fblock = 0;
-                        return EOK;
                 }
 
@@ -764 +958 @@
         }
 
-        *fblock = current_block;
-
         return EOK;
 }
@@ -772 +964 @@
  *
  */
-int ext4_filesystem_set_inode_data_block_index(ext4_inode_ref_t *inode_ref,
-                aoff64_t iblock, uint32_t fblock)
-{
-        int rc;
+int ext4_filesystem_release_inode_block(
+                ext4_inode_ref_t *inode_ref, uint32_t iblock)
+{
+        int rc;
+
+        uint32_t fblock;
 
         ext4_filesystem_t *fs = inode_ref->fs;
 
-        /* Handle inode using extents */
-        if (ext4_superblock_has_feature_compatible(fs->superblock, EXT4_FEATURE_INCOMPAT_EXTENTS) &&
-                        ext4_inode_has_flag(inode_ref->inode, EXT4_INODE_FLAG_EXTENTS)) {
-                // not reachable !!!
-                return ENOTSUP;
-        }
+        // EXTENTS are handled otherwise
+        assert(! (ext4_superblock_has_feature_incompatible(fs->superblock,
+                        EXT4_FEATURE_INCOMPAT_EXTENTS) &&
+                        ext4_inode_has_flag(inode_ref->inode, EXT4_INODE_FLAG_EXTENTS)));
+
+        ext4_inode_t *inode = inode_ref->inode;
 
         /* Handle simple case when we are dealing with direct reference */
         if (iblock < EXT4_INODE_DIRECT_BLOCK_COUNT) {
-                ext4_inode_set_direct_block(inode_ref->inode, (uint32_t)iblock, fblock);
-                inode_ref->dirty = true;
-                return EOK;
-        }
+                fblock = ext4_inode_get_direct_block(inode, iblock);
+                // Sparse file
+                if (fblock == 0) {
+                        return EOK;
+                }
+
+                ext4_inode_set_direct_block(inode, iblock, 0);
+                return ext4_balloc_free_block(inode_ref, fblock);
+        }
+
 
         /* Determine the indirection level needed to get the desired block */
@@ -806 +1006 @@
         }
 
-        uint32_t block_size = ext4_superblock_get_block_size(fs->superblock);
-
-        /* Compute offsets for the topmost level */
-        aoff64_t block_offset_in_level = iblock - fs->inode_block_limits[level-1];
-        uint32_t current_block = ext4_inode_get_indirect_block(inode_ref->inode, level-1);
-        uint32_t offset_in_block = block_offset_in_level / fs->inode_blocks_per_level[level-1];
-
-        uint32_t new_block_addr;
-        block_t *block, *new_block;
-
-        if (current_block == 0) {
-                rc = ext4_balloc_alloc_block(inode_ref, &new_block_addr);
-                if (rc != EOK) {
-                        return rc;
-                }
-
-                ext4_inode_set_indirect_block(inode_ref->inode, level - 1, new_block_addr);
-
-                inode_ref->dirty = true;
-
-                rc = block_get(&new_block, fs->device, new_block_addr, BLOCK_FLAGS_NOREAD);
-                if (rc != EOK) {
-                        ext4_balloc_free_block(inode_ref, new_block_addr);
-                        return rc;
-                }
-
-                memset(new_block->data, 0, block_size);
-                new_block->dirty = true;
-
-                rc = block_put(new_block);
-                if (rc != EOK) {
-                        return rc;
-                }
-
-                current_block = new_block_addr;
-        }
-
-        /* Navigate through other levels, until we find the block number
-         * or find null reference meaning we are dealing with sparse file
-         */
-        while (level > 0) {
-
-                rc = block_get(&block, fs->device, current_block, 0);
-                if (rc != EOK) {
-                        return rc;
-                }
-
-                current_block = uint32_t_le2host(((uint32_t*)block->data)[offset_in_block]);
-
-                if ((level > 1) && (current_block == 0)) {
-                        rc = ext4_balloc_alloc_block(inode_ref, &new_block_addr);
-                        if (rc != EOK) {
-                                block_put(block);
-                                return rc;
-                        }
-
-                        rc = block_get(&new_block, fs->device, new_block_addr, BLOCK_FLAGS_NOREAD);
-                        if (rc != EOK) {
-                                block_put(block);
-                                return rc;
-                        }
-
-                        memset(new_block->data, 0, block_size);
-                        new_block->dirty = true;
-
-                        rc = block_put(new_block);
-                        if (rc != EOK) {
-                                block_put(block);
-                                return rc;
-                        }
-
-                        ((uint32_t*)block->data)[offset_in_block] = host2uint32_t_le(new_block_addr);
-                        block->dirty = true;
-                        current_block = new_block_addr;
-                }
-
-                if (level == 1) {
-                        ((uint32_t*)block->data)[offset_in_block] = host2uint32_t_le(fblock);
-                        block->dirty = true;
-                }
-
-                rc = block_put(block);
-                if (rc != EOK) {
-                        return rc;
-                }
-
-                level -= 1;
-
-                /* If we are on the last level, break here as
-                 * there is no next level to visit
-                 */
-                if (level == 0) {
-                        break;
-                }
-
-                /* Visit the next level */
-                block_offset_in_level %= fs->inode_blocks_per_level[level];
-                offset_in_block = block_offset_in_level / fs->inode_blocks_per_level[level-1];
-        }
-
-        return EOK;
-}
-
-/** TODO comment
- *
- */
-int ext4_filesystem_release_inode_block(
-                ext4_inode_ref_t *inode_ref, uint32_t iblock)
-{
-        int rc;
-
-        uint32_t fblock;
-
-        ext4_filesystem_t *fs = inode_ref->fs;
-
-        // EXTENTS are handled otherwise
-        assert(! (ext4_superblock_has_feature_incompatible(fs->superblock,
-                        EXT4_FEATURE_INCOMPAT_EXTENTS) &&
-                        ext4_inode_has_flag(inode_ref->inode, EXT4_INODE_FLAG_EXTENTS)));
-
-        ext4_inode_t *inode = inode_ref->inode;
-
-        /* Handle simple case when we are dealing with direct reference */
-        if (iblock < EXT4_INODE_DIRECT_BLOCK_COUNT) {
-                fblock = ext4_inode_get_direct_block(inode, iblock);
-                // Sparse file
-                if (fblock == 0) {
-                        return EOK;
-                }
-
-                ext4_inode_set_direct_block(inode, iblock, 0);
-                return ext4_balloc_free_block(inode_ref, fblock);
-        }
-
-
-        /* Determine the indirection level needed to get the desired block */
-        int level = -1;
-        for (int i = 1; i < 4; i++) {
-                if (iblock < fs->inode_block_limits[i]) {
-                        level = i;
-                        break;
-                }
-        }
-
-        if (level == -1) {
-                return EIO;
-        }
-
         /* Compute offsets for the topmost level */
         aoff64_t block_offset_in_level = iblock - fs->inode_block_limits[level-1];
@@ -1006 +1058 @@
 }
 
-/** TODO comment
- *
+/** Append following logical block to the i-node.
+ *
+ * @param inode_ref                     i-node to append block to
+ * @param fblock                        output physical block address of newly allocated block
+ * @param iblock                        output logical number of newly allocated block
+ * @return                                      error code
  */
 int ext4_filesystem_append_inode_block(ext4_inode_ref_t *inode_ref,
@@ -1031 +1087 @@
         uint32_t block_size = ext4_superblock_get_block_size(sb);
 
-        // TODO zarovnat inode size a ne assert!!!
-        assert(inode_size % block_size == 0);
+        // Align size i-node size
+        if ((inode_size % block_size) != 0) {
+                inode_size += block_size - (inode_size % block_size);
+        }
 
         // Logical blocks are numbered from 0
         uint32_t new_block_idx = inode_size / block_size;
 
+        // Allocate new physical block
         uint32_t phys_block;
         rc =  ext4_balloc_alloc_block(inode_ref, &phys_block);
@@ -1043 +1102 @@
         }
 
+        // Add physical block address to the i-node
         rc = ext4_filesystem_set_inode_data_block_index(inode_ref, new_block_idx, phys_block);
         if (rc != EOK) {
@@ -1049 +1109 @@
         }
 
+        // Update i-node
         ext4_inode_set_size(inode_ref->inode, inode_size + block_size);
-
         inode_ref->dirty = true;
 
         *fblock = phys_block;
         *iblock = new_block_idx;
+
         return EOK;
 }
 
-/** TODO comment
- *
+/** Add orphaned i-node to the orphans linked list.
+ *
+ * @param inode_ref             i-node to be added to orphans list
+ * @return                              error code
  */
 int ext4_filesystem_add_orphan(ext4_inode_ref_t *inode_ref)
@@ -1065 +1128 @@
         uint32_t next_orphan = ext4_superblock_get_last_orphan(
                         inode_ref->fs->superblock);
+
+        // Deletion time is used for holding next item of the list
         ext4_inode_set_deletion_time(inode_ref->inode, next_orphan);
+
+        // Head of the list is in the superblock
         ext4_superblock_set_last_orphan(
                         inode_ref->fs->superblock, inode_ref->index);
@@ -1073 +1140 @@
 }
 
-/** TODO comment
- *
+/** Delete orphaned i-node from the orphans linked list.
+ *
+ * @param inode_ref             i-node to be deleted from the orphans list
+ * @return                              error code
  */
 int ext4_filesystem_delete_orphan(ext4_inode_ref_t *inode_ref)
@@ -1080 +1149 @@
         int rc;
 
+        // Get head of the linked list
         uint32_t last_orphan = ext4_superblock_get_last_orphan(
                         inode_ref->fs->superblock);
@@ -1086 +1156 @@
         uint32_t next_orphan = ext4_inode_get_deletion_time(inode_ref->inode);
 
+        // Check if the head is the target
         if (last_orphan == inode_ref->index) {
                 ext4_superblock_set_last_orphan(inode_ref->fs->superblock, next_orphan);
@@ -1098 +1169 @@
                 return rc;
         }
+
         next_orphan = ext4_inode_get_deletion_time(current->inode);
 
-        bool found;
-
+        bool found = false;
+
+        // Walk thourgh the linked list
         while (next_orphan != 0) {
+
+                // Found?
                 if (next_orphan == inode_ref->index) {
                         next_orphan = ext4_inode_get_deletion_time(inode_ref->inode);
@@ -1121 +1196 @@
         }
 
-        ext4_inode_set_deletion_time(inode_ref->inode, 0);
+        if (found) {
+                ext4_inode_set_deletion_time(inode_ref->inode, 0);
+        }
 
         rc = ext4_filesystem_put_inode_ref(current);

uspace/srv/fs/ext4fs/ext4fs_ops.c

@@ -1441 +1441 @@
 
 /** Close file.
- *'
+ *
  * @param service_id    device identifier
  * @param index         i-node number