--- /dev/null
+/**
+ * \file fsw_ext4.c
+ * ext4 file system driver code.
+ */
+
+/*-
+ * Copyright (c) 2012 Stefan Agner
+ * Portions Copyright (c) 2006 Christoph Pfisterer
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ */
+
+#include "fsw_ext4.h"
+
+
+// functions
+
+static fsw_status_t fsw_ext4_volume_mount(struct fsw_ext4_volume *vol);
+static void fsw_ext4_volume_free(struct fsw_ext4_volume *vol);
+static fsw_status_t fsw_ext4_volume_stat(struct fsw_ext4_volume *vol, struct fsw_volume_stat *sb);
+
+static fsw_status_t fsw_ext4_dnode_fill(struct fsw_ext4_volume *vol, struct fsw_ext4_dnode *dno);
+static void fsw_ext4_dnode_free(struct fsw_ext4_volume *vol, struct fsw_ext4_dnode *dno);
+static fsw_status_t fsw_ext4_dnode_stat(struct fsw_ext4_volume *vol, struct fsw_ext4_dnode *dno,
+ struct fsw_dnode_stat *sb);
+static fsw_status_t fsw_ext4_get_extent(struct fsw_ext4_volume *vol, struct fsw_ext4_dnode *dno,
+ struct fsw_extent *extent);
+
+static fsw_status_t fsw_ext4_dir_lookup(struct fsw_ext4_volume *vol, struct fsw_ext4_dnode *dno,
+ struct fsw_string *lookup_name, struct fsw_ext4_dnode **child_dno);
+static fsw_status_t fsw_ext4_dir_read(struct fsw_ext4_volume *vol, struct fsw_ext4_dnode *dno,
+ struct fsw_shandle *shand, struct fsw_ext4_dnode **child_dno);
+static fsw_status_t fsw_ext4_read_dentry(struct fsw_shandle *shand, struct ext4_dir_entry *entry);
+
+static fsw_status_t fsw_ext4_readlink(struct fsw_ext4_volume *vol, struct fsw_ext4_dnode *dno,
+ struct fsw_string *link);
+
+//
+// Dispatch Table
+//
+
+struct fsw_fstype_table FSW_FSTYPE_TABLE_NAME(ext4) = {
+ { FSW_STRING_TYPE_ISO88591, 4, 4, "ext4" },
+ sizeof(struct fsw_ext4_volume),
+ sizeof(struct fsw_ext4_dnode),
+
+ fsw_ext4_volume_mount,
+ fsw_ext4_volume_free,
+ fsw_ext4_volume_stat,
+ fsw_ext4_dnode_fill,
+ fsw_ext4_dnode_free,
+ fsw_ext4_dnode_stat,
+ fsw_ext4_get_extent,
+ fsw_ext4_dir_lookup,
+ fsw_ext4_dir_read,
+ fsw_ext4_readlink,
+};
+
+/**
+ * Mount an ext4 volume. Reads the superblock and constructs the
+ * root directory dnode.
+ */
+
+static fsw_status_t fsw_ext4_volume_mount(struct fsw_ext4_volume *vol)
+{
+ fsw_status_t status;
+ void *buffer;
+ fsw_u32 blocksize;
+ fsw_u32 groupcnt, groupno, gdesc_per_block, gdesc_bno, gdesc_index;
+ struct ext4_group_desc *gdesc;
+ int i;
+ struct fsw_string s;
+
+ // allocate memory to keep the superblock around
+ status = fsw_alloc(sizeof(struct ext4_super_block), &vol->sb);
+ if (status)
+ return status;
+
+ // read the superblock into its buffer
+ fsw_set_blocksize(vol, EXT4_SUPERBLOCK_BLOCKSIZE, EXT4_SUPERBLOCK_BLOCKSIZE);
+ status = fsw_block_get(vol, EXT4_SUPERBLOCK_BLOCKNO, 0, &buffer);
+ if (status)
+ return status;
+ fsw_memcpy(vol->sb, buffer, sizeof(struct ext4_super_block));
+ fsw_block_release(vol, EXT4_SUPERBLOCK_BLOCKNO, buffer);
+
+ // check the superblock
+ if (vol->sb->s_magic != EXT4_SUPER_MAGIC)
+ return FSW_UNSUPPORTED;
+ if (vol->sb->s_rev_level != EXT4_GOOD_OLD_REV &&
+ vol->sb->s_rev_level != EXT4_DYNAMIC_REV)
+ return FSW_UNSUPPORTED;
+
+ FSW_MSG_DEBUG((FSW_MSGSTR("fsw_ext4_volume_mount: Incompat flag %x\n"), vol->sb->s_feature_incompat));
+
+ if (vol->sb->s_rev_level == EXT4_DYNAMIC_REV &&
+ (vol->sb->s_feature_incompat & ~(EXT4_FEATURE_INCOMPAT_FILETYPE | EXT4_FEATURE_INCOMPAT_RECOVER)))
+ return FSW_UNSUPPORTED;
+
+
+ if (vol->sb->s_rev_level == EXT4_DYNAMIC_REV &&
+ (vol->sb->s_feature_incompat & EXT4_FEATURE_INCOMPAT_RECOVER))
+ {
+ FSW_MSG_DEBUG((FSW_MSGSTR("fsw_ext4_volume_mount: This ext3 file system needs recovery\n")));
+ // Print(L"Ext4 WARNING: This file system needs recovery, trying to use it anyway.\n");
+ }
+
+ // set real blocksize
+ blocksize = EXT4_BLOCK_SIZE(vol->sb);
+ fsw_set_blocksize(vol, blocksize, blocksize);
+
+ // get other info from superblock
+ vol->ind_bcnt = EXT4_ADDR_PER_BLOCK(vol->sb);
+ vol->dind_bcnt = vol->ind_bcnt * vol->ind_bcnt;
+ vol->inode_size = EXT4_INODE_SIZE(vol->sb);
+
+ for (i = 0; i < 16; i++)
+ if (vol->sb->s_volume_name[i] == 0)
+ break;
+ s.type = FSW_STRING_TYPE_ISO88591;
+ s.size = s.len = i;
+ s.data = vol->sb->s_volume_name;
+ status = fsw_strdup_coerce(&vol->g.label, vol->g.host_string_type, &s);
+ if (status)
+ return status;
+
+ // read the group descriptors to get inode table offsets
+ groupcnt = ((vol->sb->s_inodes_count - 2) / vol->sb->s_inodes_per_group) + 1;
+ gdesc_per_block = (vol->g.phys_blocksize / sizeof(struct ext4_group_desc));
+
+ status = fsw_alloc(sizeof(fsw_u32) * groupcnt, &vol->inotab_bno);
+ if (status)
+ return status;
+ for (groupno = 0; groupno < groupcnt; groupno++) {
+ // get the block group descriptor
+ gdesc_bno = (vol->sb->s_first_data_block + 1) + groupno / gdesc_per_block;
+ gdesc_index = groupno % gdesc_per_block;
+ status = fsw_block_get(vol, gdesc_bno, 1, (void **)&buffer);
+ if (status)
+ return status;
+ gdesc = ((struct ext4_group_desc *)(buffer)) + gdesc_index;
+ vol->inotab_bno[groupno] = gdesc->bg_inode_table_lo;
+ fsw_block_release(vol, gdesc_bno, buffer);
+ }
+
+ // setup the root dnode
+ status = fsw_dnode_create_root(vol, EXT4_ROOT_INO, &vol->g.root);
+ if (status)
+ return status;
+
+ FSW_MSG_DEBUG((FSW_MSGSTR("fsw_ext4_volume_mount: success, blocksize %d\n"), blocksize));
+
+ return FSW_SUCCESS;
+}
+
+/**
+ * Free the volume data structure. Called by the core after an unmount or after
+ * an unsuccessful mount to release the memory used by the file system type specific
+ * part of the volume structure.
+ */
+
+static void fsw_ext4_volume_free(struct fsw_ext4_volume *vol)
+{
+ if (vol->sb)
+ fsw_free(vol->sb);
+ if (vol->inotab_bno)
+ fsw_free(vol->inotab_bno);
+}
+
+/**
+ * Get in-depth information on a volume.
+ */
+
+static fsw_status_t fsw_ext4_volume_stat(struct fsw_ext4_volume *vol, struct fsw_volume_stat *sb)
+{
+ sb->total_bytes = (fsw_u64)vol->sb->s_blocks_count_lo * vol->g.log_blocksize;
+ sb->free_bytes = (fsw_u64)vol->sb->s_free_blocks_count_lo * vol->g.log_blocksize;
+ return FSW_SUCCESS;
+}
+
+/**
+ * Get full information on a dnode from disk. This function is called by the core
+ * whenever it needs to access fields in the dnode structure that may not
+ * be filled immediately upon creation of the dnode. In the case of ext4, we
+ * delay fetching of the inode structure until dnode_fill is called. The size and
+ * type fields are invalid until this function has been called.
+ */
+
+static fsw_status_t fsw_ext4_dnode_fill(struct fsw_ext4_volume *vol, struct fsw_ext4_dnode *dno)
+{
+ fsw_status_t status;
+ fsw_u32 groupno, ino_in_group, ino_bno, ino_index;
+ fsw_u8 *buffer;
+
+ if (dno->raw)
+ return FSW_SUCCESS;
+
+ FSW_MSG_DEBUG((FSW_MSGSTR("fsw_ext4_dnode_fill: inode %d\n"), dno->g.dnode_id));
+
+ // read the inode block
+ groupno = (dno->g.dnode_id - 1) / vol->sb->s_inodes_per_group;
+ ino_in_group = (dno->g.dnode_id - 1) % vol->sb->s_inodes_per_group;
+ ino_bno = vol->inotab_bno[groupno] +
+ ino_in_group / (vol->g.phys_blocksize / vol->inode_size);
+ ino_index = ino_in_group % (vol->g.phys_blocksize / vol->inode_size);
+ status = fsw_block_get(vol, ino_bno, 2, (void **)&buffer);
+ if (status)
+ return status;
+
+ // keep our inode around
+ status = fsw_memdup((void **)&dno->raw, buffer + ino_index * vol->inode_size, vol->inode_size);
+ fsw_block_release(vol, ino_bno, buffer);
+ if (status)
+ return status;
+
+ // get info from the inode
+ dno->g.size = dno->raw->i_size_lo; // TODO: check docs for 64-bit sized files
+
+ if (S_ISREG(dno->raw->i_mode))
+ dno->g.type = FSW_DNODE_TYPE_FILE;
+ else if (S_ISDIR(dno->raw->i_mode))
+ dno->g.type = FSW_DNODE_TYPE_DIR;
+ else if (S_ISLNK(dno->raw->i_mode))
+ dno->g.type = FSW_DNODE_TYPE_SYMLINK;
+ else
+ dno->g.type = FSW_DNODE_TYPE_SPECIAL;
+
+ return FSW_SUCCESS;
+}
+
+/**
+ * Free the dnode data structure. Called by the core when deallocating a dnode
+ * structure to release the memory used by the file system type specific part
+ * of the dnode structure.
+ */
+
+static void fsw_ext4_dnode_free(struct fsw_ext4_volume *vol, struct fsw_ext4_dnode *dno)
+{
+ if (dno->raw)
+ fsw_free(dno->raw);
+}
+
+/**
+ * Get in-depth information on a dnode. The core makes sure that fsw_ext4_dnode_fill
+ * has been called on the dnode before this function is called. Note that some
+ * data is not directly stored into the structure, but passed to a host-specific
+ * callback that converts it to the host-specific format.
+ */
+
+static fsw_status_t fsw_ext4_dnode_stat(struct fsw_ext4_volume *vol, struct fsw_ext4_dnode *dno,
+ struct fsw_dnode_stat *sb)
+{
+ sb->used_bytes = dno->raw->i_blocks_lo * EXT4_BLOCK_SIZE(vol->sb); // very, very strange...
+ sb->store_time_posix(sb, FSW_DNODE_STAT_CTIME, dno->raw->i_ctime);
+ sb->store_time_posix(sb, FSW_DNODE_STAT_ATIME, dno->raw->i_atime);
+ sb->store_time_posix(sb, FSW_DNODE_STAT_MTIME, dno->raw->i_mtime);
+ sb->store_attr_posix(sb, dno->raw->i_mode);
+
+ return FSW_SUCCESS;
+}
+
+/**
+ * Retrieve file data mapping information. This function is called by the core when
+ * fsw_shandle_read needs to know where on the disk the required piece of the file's
+ * data can be found. The core makes sure that fsw_ext4_dnode_fill has been called
+ * on the dnode before. Our task here is to get the physical disk block number for
+ * the requested logical block number.
+ *
+ * TODO...
+ * The ext2 file system does not use extents, but stores a list of block numbers
+ * using the usual direct, indirect, double-indirect, triple-indirect scheme. To
+ * optimize access, this function checks if the following file blocks are mapped
+ * to consecutive disk blocks and returns a combined extent if possible.
+ */
+
+static fsw_status_t fsw_ext4_get_extent(struct fsw_ext4_volume *vol, struct fsw_ext4_dnode *dno,
+ struct fsw_extent *extent)
+{
+ fsw_status_t status;
+ fsw_u32 bno, release_bno, buf_bcnt, file_bcnt;
+ fsw_u32 *buffer;
+ int path[5], i;
+
+ // Preconditions: The caller has checked that the requested logical block
+ // is within the file's size. The dnode has complete information, i.e.
+ // fsw_ext4_dnode_read_info was called successfully on it.
+
+ extent->type = FSW_EXTENT_TYPE_PHYSBLOCK;
+ extent->log_count = 1;
+ bno = extent->log_start;
+
+ // try direct block pointers in the inode
+ if (bno < EXT4_NDIR_BLOCKS) {
+ path[0] = bno;
+ path[1] = -1;
+ } else {
+ bno -= EXT4_NDIR_BLOCKS;
+
+ // try indirect block
+ if (bno < vol->ind_bcnt) {
+ path[0] = EXT4_IND_BLOCK;
+ path[1] = bno;
+ path[2] = -1;
+ } else {
+ bno -= vol->ind_bcnt;
+
+ // try double-indirect block
+ if (bno < vol->dind_bcnt) {
+ path[0] = EXT4_DIND_BLOCK;
+ path[1] = bno / vol->ind_bcnt;
+ path[2] = bno % vol->ind_bcnt;
+ path[3] = -1;
+ } else {
+ bno -= vol->dind_bcnt;
+
+ // use the triple-indirect block
+ path[0] = EXT4_TIND_BLOCK;
+ path[1] = bno / vol->dind_bcnt;
+ path[2] = (bno / vol->ind_bcnt) % vol->ind_bcnt;
+ path[3] = bno % vol->ind_bcnt;
+ path[4] = -1;
+ }
+ }
+ }
+
+ // follow the indirection path
+ buffer = dno->raw->i_block;
+ buf_bcnt = EXT4_NDIR_BLOCKS;
+ release_bno = 0;
+ for (i = 0; ; i++) {
+ bno = buffer[path[i]];
+ if (bno == 0) {
+ extent->type = FSW_EXTENT_TYPE_SPARSE;
+ if (release_bno)
+ fsw_block_release(vol, release_bno, buffer);
+ return FSW_SUCCESS;
+ }
+ if (path[i+1] < 0)
+ break;
+
+ if (release_bno)
+ fsw_block_release(vol, release_bno, buffer);
+ status = fsw_block_get(vol, bno, 1, (void **)&buffer);
+ if (status)
+ return status;
+ release_bno = bno;
+ buf_bcnt = vol->ind_bcnt;
+ }
+ extent->phys_start = bno;
+
+ // check if the following blocks can be aggregated into one extent
+ file_bcnt = (fsw_u32)((dno->g.size + vol->g.log_blocksize - 1) & (vol->g.log_blocksize - 1));
+ while (path[i] + extent->log_count < buf_bcnt && // indirect block has more block pointers
+ extent->log_start + extent->log_count < file_bcnt) { // file has more blocks
+ if (buffer[path[i] + extent->log_count] == buffer[path[i] + extent->log_count - 1] + 1)
+ extent->log_count++;
+ else
+ break;
+ }
+
+ if (release_bno)
+ fsw_block_release(vol, release_bno, buffer);
+ return FSW_SUCCESS;
+}
+
+/**
+ * Lookup a directory's child dnode by name. This function is called on a directory
+ * to retrieve the directory entry with the given name. A dnode is constructed for
+ * this entry and returned. The core makes sure that fsw_ext4_dnode_fill has been called
+ * and the dnode is actually a directory.
+ */
+
+static fsw_status_t fsw_ext4_dir_lookup(struct fsw_ext4_volume *vol, struct fsw_ext4_dnode *dno,
+ struct fsw_string *lookup_name, struct fsw_ext4_dnode **child_dno_out)
+{
+ fsw_status_t status;
+ struct fsw_shandle shand;
+ fsw_u32 child_ino;
+ struct ext4_dir_entry entry;
+ struct fsw_string entry_name;
+
+ // Preconditions: The caller has checked that dno is a directory node.
+
+ entry_name.type = FSW_STRING_TYPE_ISO88591;
+
+ // setup handle to read the directory
+ status = fsw_shandle_open(dno, &shand);
+ if (status)
+ return status;
+
+ // scan the directory for the file
+ child_ino = 0;
+ while (child_ino == 0) {
+ // read next entry
+ status = fsw_ext4_read_dentry(&shand, &entry);
+ if (status)
+ goto errorexit;
+ if (entry.inode == 0) {
+ // end of directory reached
+ status = FSW_NOT_FOUND;
+ goto errorexit;
+ }
+
+ // compare name
+ entry_name.len = entry_name.size = entry.name_len;
+ entry_name.data = entry.name;
+ if (fsw_streq(lookup_name, &entry_name)) {
+ child_ino = entry.inode;
+ break;
+ }
+ }
+
+ // setup a dnode for the child item
+ status = fsw_dnode_create(dno, child_ino, FSW_DNODE_TYPE_UNKNOWN, &entry_name, child_dno_out);
+
+errorexit:
+ fsw_shandle_close(&shand);
+ return status;
+}
+
+/**
+ * Get the next directory entry when reading a directory. This function is called during
+ * directory iteration to retrieve the next directory entry. A dnode is constructed for
+ * the entry and returned. The core makes sure that fsw_ext4_dnode_fill has been called
+ * and the dnode is actually a directory. The shandle provided by the caller is used to
+ * record the position in the directory between calls.
+ */
+
+static fsw_status_t fsw_ext4_dir_read(struct fsw_ext4_volume *vol, struct fsw_ext4_dnode *dno,
+ struct fsw_shandle *shand, struct fsw_ext4_dnode **child_dno_out)
+{
+ fsw_status_t status;
+ struct ext4_dir_entry entry;
+ struct fsw_string entry_name;
+
+ // Preconditions: The caller has checked that dno is a directory node. The caller
+ // has opened a storage handle to the directory's storage and keeps it around between
+ // calls.
+
+ while (1) {
+ // read next entry
+ status = fsw_ext4_read_dentry(shand, &entry);
+ if (status)
+ return status;
+ if (entry.inode == 0) // end of directory
+ return FSW_NOT_FOUND;
+
+ // skip . and ..
+ if ((entry.name_len == 1 && entry.name[0] == '.') ||
+ (entry.name_len == 2 && entry.name[0] == '.' && entry.name[1] == '.'))
+ continue;
+ break;
+ }
+
+ // setup name
+ entry_name.type = FSW_STRING_TYPE_ISO88591;
+ entry_name.len = entry_name.size = entry.name_len;
+ entry_name.data = entry.name;
+
+ // setup a dnode for the child item
+ status = fsw_dnode_create(dno, entry.inode, FSW_DNODE_TYPE_UNKNOWN, &entry_name, child_dno_out);
+
+ return status;
+}
+
+/**
+ * Read a directory entry from the directory's raw data. This internal function is used
+ * to read a raw ext2 directory entry into memory. The shandle's position pointer is adjusted
+ * to point to the next entry.
+ */
+
+static fsw_status_t fsw_ext4_read_dentry(struct fsw_shandle *shand, struct ext4_dir_entry *entry)
+{
+ fsw_status_t status;
+ fsw_u32 buffer_size;
+
+ while (1) {
+ // read dir_entry header (fixed length)
+ buffer_size = 8;
+ status = fsw_shandle_read(shand, &buffer_size, entry);
+ if (status)
+ return status;
+
+ if (buffer_size < 8 || entry->rec_len == 0) {
+ // end of directory reached
+ entry->inode = 0;
+ return FSW_SUCCESS;
+ }
+ if (entry->rec_len < 8)
+ return FSW_VOLUME_CORRUPTED;
+ if (entry->inode != 0) {
+ // this entry is used
+ if (entry->rec_len < 8 + entry->name_len)
+ return FSW_VOLUME_CORRUPTED;
+ break;
+ }
+
+ // valid, but unused entry, skip it
+ shand->pos += entry->rec_len - 8;
+ }
+
+ // read file name (variable length)
+ buffer_size = entry->name_len;
+ status = fsw_shandle_read(shand, &buffer_size, entry->name);
+ if (status)
+ return status;
+ if (buffer_size < entry->name_len)
+ return FSW_VOLUME_CORRUPTED;
+
+ // skip any remaining padding
+ shand->pos += entry->rec_len - (8 + entry->name_len);
+
+ return FSW_SUCCESS;
+}
+
+/**
+ * Get the target path of a symbolic link. This function is called when a symbolic
+ * link needs to be resolved. The core makes sure that the fsw_ext4_dnode_fill has been
+ * called on the dnode and that it really is a symlink.
+ *
+ * For ext4, the target path can be stored inline in the inode structure (in the space
+ * otherwise occupied by the block pointers) or in the inode's data. There is no flag
+ * indicating this, only the number of blocks entry (i_blocks) can be used as an
+ * indication. The check used here comes from the Linux kernel.
+ */
+
+static fsw_status_t fsw_ext4_readlink(struct fsw_ext4_volume *vol, struct fsw_ext4_dnode *dno,
+ struct fsw_string *link_target)
+{
+ fsw_status_t status;
+ int ea_blocks;
+ struct fsw_string s;
+
+ if (dno->g.size > FSW_PATH_MAX)
+ return FSW_VOLUME_CORRUPTED;
+
+ /* Linux kernels ext4_inode_is_fast_symlink... */
+ ea_blocks = dno->raw->i_file_acl_lo ? (vol->g.log_blocksize >> 9) : 0;
+
+ if (dno->raw->i_blocks_lo - ea_blocks == 0) {
+ // "fast" symlink, path is stored inside the inode
+ s.type = FSW_STRING_TYPE_ISO88591;
+ s.size = s.len = (int)dno->g.size;
+ s.data = dno->raw->i_block;
+ status = fsw_strdup_coerce(link_target, vol->g.host_string_type, &s);
+ } else {
+ // "slow" symlink, path is stored in normal inode data
+ status = fsw_dnode_readlink_data(dno, link_target);
+ }
+
+ return status;
+}
+
+// EOF
--- /dev/null
+/**
+ * \file fsw_ext4_disk.h
+ * ext4 file system on-disk structures.
+ */
+
+/*-
+ * Copyright (c) 2012 Stefan Agner
+ * Portions Copyright (c) 2006 Christoph Pfisterer
+ * Portions Copyright (c) 1991-2012 by various Linux kernel contributors
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ */
+
+#ifndef _FSW_EXT4_DISK_H_
+#define _FSW_EXT4_DISK_H_
+
+// types
+
+typedef fsw_s8 __s8;
+typedef fsw_u8 __u8;
+typedef fsw_s16 __s16;
+typedef fsw_u16 __u16;
+typedef fsw_s32 __s32;
+typedef fsw_u32 __u32;
+typedef fsw_s64 __s64;
+typedef fsw_u64 __u64;
+
+typedef __u16 __le16;
+typedef __u32 __le32;
+typedef __u64 __le64;
+
+//
+// from Linux kernel, fs/ext4/ext4.h
+//
+
+/*
+ * Special inode numbers
+ */
+#define EXT4_BAD_INO 1 /* Bad blocks inode */
+#define EXT4_ROOT_INO 2 /* Root inode */
+#define EXT4_USR_QUOTA_INO 3 /* User quota inode */
+#define EXT4_GRP_QUOTA_INO 4 /* Group quota inode */
+#define EXT4_BOOT_LOADER_INO 5 /* Boot loader inode */
+#define EXT4_UNDEL_DIR_INO 6 /* Undelete directory inode */
+#define EXT4_RESIZE_INO 7 /* Reserved group descriptors inode */
+#define EXT4_JOURNAL_INO 8 /* Journal inode */
+
+/*
+ * The second extended file system magic number
+ */
+#define EXT4_SUPER_MAGIC 0xEF53
+
+/*
+ * Macro-instructions used to manage several block sizes
+ */
+#define EXT4_MIN_BLOCK_SIZE 1024
+#define EXT4_MAX_BLOCK_SIZE 4096
+#define EXT4_MIN_BLOCK_LOG_SIZE 10
+#define EXT4_BLOCK_SIZE(s) (EXT4_MIN_BLOCK_SIZE << (s)->s_log_block_size)
+#define EXT4_ADDR_PER_BLOCK(s) (EXT4_BLOCK_SIZE(s) / sizeof (__u32))
+#define EXT4_BLOCK_SIZE_BITS(s) ((s)->s_log_block_size + 10)
+#define EXT4_INODE_SIZE(s) (((s)->s_rev_level == EXT4_GOOD_OLD_REV) ? \
+ EXT4_GOOD_OLD_INODE_SIZE : \
+ (s)->s_inode_size)
+
+/*
+ * Structure of a blocks group descriptor
+ */
+struct ext4_group_desc
+{
+ __le32 bg_block_bitmap_lo; /* Blocks bitmap block */
+ __le32 bg_inode_bitmap_lo; /* Inodes bitmap block */
+ __le32 bg_inode_table_lo; /* Inodes table block */
+ __le16 bg_free_blocks_count_lo;/* Free blocks count */
+ __le16 bg_free_inodes_count_lo;/* Free inodes count */
+ __le16 bg_used_dirs_count_lo; /* Directories count */
+ __le16 bg_flags; /* EXT4_BG_flags (INODE_UNINIT, etc) */
+ __le32 bg_exclude_bitmap_lo; /* Exclude bitmap for snapshots */
+ __le16 bg_block_bitmap_csum_lo;/* crc32c(s_uuid+grp_num+bbitmap) LE */
+ __le16 bg_inode_bitmap_csum_lo;/* crc32c(s_uuid+grp_num+ibitmap) LE */
+ __le16 bg_itable_unused_lo; /* Unused inodes count */
+ __le16 bg_checksum; /* crc16(sb_uuid+group+desc) */
+ __le32 bg_block_bitmap_hi; /* Blocks bitmap block MSB */
+ __le32 bg_inode_bitmap_hi; /* Inodes bitmap block MSB */
+ __le32 bg_inode_table_hi; /* Inodes table block MSB */
+ __le16 bg_free_blocks_count_hi;/* Free blocks count MSB */
+ __le16 bg_free_inodes_count_hi;/* Free inodes count MSB */
+ __le16 bg_used_dirs_count_hi; /* Directories count MSB */
+ __le16 bg_itable_unused_hi; /* Unused inodes count MSB */
+ __le32 bg_exclude_bitmap_hi; /* Exclude bitmap block MSB */
+ __le16 bg_block_bitmap_csum_hi;/* crc32c(s_uuid+grp_num+bbitmap) BE */
+ __le16 bg_inode_bitmap_csum_hi;/* crc32c(s_uuid+grp_num+ibitmap) BE */
+ __u32 bg_reserved;
+};
+
+
+/*
+ * Macro-instructions used to manage group descriptors
+ */
+#define EXT4_DESC_SIZE(s) ((s)->s_desc_size)
+#define EXT4_BLOCKS_PER_GROUP(s) ((s)->s_blocks_per_group)
+#define EXT4_DESC_PER_BLOCK(s) (EXT4_BLOCK_SIZE(s) / EXT4_DESC_SIZE(s))
+#define EXT4_INODES_PER_GROUP(s) ((s)->s_inodes_per_group)
+
+/*
+ * Constants relative to the data blocks
+ */
+#define EXT4_NDIR_BLOCKS 12
+#define EXT4_IND_BLOCK EXT4_NDIR_BLOCKS
+#define EXT4_DIND_BLOCK (EXT4_IND_BLOCK + 1)
+#define EXT4_TIND_BLOCK (EXT4_DIND_BLOCK + 1)
+#define EXT4_N_BLOCKS (EXT4_TIND_BLOCK + 1)
+
+/*
+ * Inode flags
+ */
+#define EXT4_SECRM_FL 0x00000001 /* Secure deletion */
+#define EXT4_UNRM_FL 0x00000002 /* Undelete */
+#define EXT4_COMPR_FL 0x00000004 /* Compress file */
+#define EXT4_SYNC_FL 0x00000008 /* Synchronous updates */
+#define EXT4_IMMUTABLE_FL 0x00000010 /* Immutable file */
+#define EXT4_APPEND_FL 0x00000020 /* writes to file may only append */
+#define EXT4_NODUMP_FL 0x00000040 /* do not dump file */
+#define EXT4_NOATIME_FL 0x00000080 /* do not update atime */
+/* Reserved for compression usage... */
+#define EXT4_DIRTY_FL 0x00000100
+#define EXT4_COMPRBLK_FL 0x00000200 /* One or more compressed clusters */
+#define EXT4_NOCOMP_FL 0x00000400 /* Don't compress */
+#define EXT4_ECOMPR_FL 0x00000800 /* Compression error */
+/* End compression flags --- maybe not all used */
+#define EXT4_INDEX_FL 0x00001000 /* hash-indexed directory */
+#define EXT4_IMAGIC_FL 0x00002000 /* AFS directory */
+#define EXT4_JOURNAL_DATA_FL 0x00004000 /* Reserved for ext3 */
+#define EXT4_NOTAIL_FL 0x00008000 /* file tail should not be merged */
+#define EXT4_DIRSYNC_FL 0x00010000 /* dirsync behaviour (directories only) */
+#define EXT4_TOPDIR_FL 0x00020000 /* Top of directory hierarchies*/
+#define EXT4_HUGE_FILE_FL 0x00040000 /* Set to each huge file */
+#define EXT4_EXTENTS_FL 0x00080000 /* Inode uses extents */
+#define EXT4_EA_INODE_FL 0x00200000 /* Inode used for large EA */
+#define EXT4_EOFBLOCKS_FL 0x00400000 /* Blocks allocated beyond EOF */
+#define EXT4_RESERVED_FL 0x80000000 /* reserved for ext4 lib */
+
+#define EXT4_FL_USER_VISIBLE 0x004BDFFF /* User visible flags */
+#define EXT4_FL_USER_MODIFIABLE 0x004B80FF /* User modifiable flags */
+
+
+/*
+ * Structure of an inode on the disk
+ */
+struct ext4_inode {
+ __le16 i_mode; /* File mode */
+ __le16 i_uid; /* Low 16 bits of Owner Uid */
+ __le32 i_size_lo; /* Size in bytes */
+ __le32 i_atime; /* Access time */
+ __le32 i_ctime; /* Inode Change time */
+ __le32 i_mtime; /* Modification time */
+ __le32 i_dtime; /* Deletion Time */
+ __le16 i_gid; /* Low 16 bits of Group Id */
+ __le16 i_links_count; /* Links count */
+ __le32 i_blocks_lo; /* Blocks count */
+ __le32 i_flags; /* File flags */
+ union {
+ struct {
+ __le32 l_i_version;
+ } linux1;
+ struct {
+ __u32 h_i_translator;
+ } hurd1;
+ struct {
+ __u32 m_i_reserved1;
+ } masix1;
+ } osd1; /* OS dependent 1 */
+ __le32 i_block[EXT4_N_BLOCKS];/* Pointers to blocks */
+ __le32 i_generation; /* File version (for NFS) */
+ __le32 i_file_acl_lo; /* File ACL */
+ __le32 i_size_high;
+ __le32 i_obso_faddr; /* Obsoleted fragment address */
+ union {
+ struct {
+ __le16 l_i_blocks_high; /* were l_i_reserved1 */
+ __le16 l_i_file_acl_high;
+ __le16 l_i_uid_high; /* these 2 fields */
+ __le16 l_i_gid_high; /* were reserved2[0] */
+ __le16 l_i_checksum_lo;/* crc32c(uuid+inum+inode) LE */
+ __le16 l_i_reserved;
+ } linux2;
+ struct {
+ __le16 h_i_reserved1; /* Obsoleted fragment number/size which are removed in ext4 */
+ __u16 h_i_mode_high;
+ __u16 h_i_uid_high;
+ __u16 h_i_gid_high;
+ __u32 h_i_author;
+ } hurd2;
+ struct {
+ __le16 h_i_reserved1; /* Obsoleted fragment number/size which are removed in ext4 */
+ __le16 m_i_file_acl_high;
+ __u32 m_i_reserved2[2];
+ } masix2;
+ } osd2; /* OS dependent 2 */
+ __le16 i_extra_isize;
+ __le16 i_checksum_hi; /* crc32c(uuid+inum+inode) BE */
+ __le32 i_ctime_extra; /* extra Change time (nsec << 2 | epoch) */
+ __le32 i_mtime_extra; /* extra Modification time(nsec << 2 | epoch) */
+ __le32 i_atime_extra; /* extra Access time (nsec << 2 | epoch) */
+ __le32 i_crtime; /* File Creation time */
+ __le32 i_crtime_extra; /* extra FileCreationtime (nsec << 2 | epoch) */
+ __le32 i_version_hi; /* high 32 bits for 64-bit version */
+};
+
+/*
+ * Structure of the super block
+ */
+struct ext4_super_block {
+/*00*/ __le32 s_inodes_count; /* Inodes count */
+ __le32 s_blocks_count_lo; /* Blocks count */
+ __le32 s_r_blocks_count_lo; /* Reserved blocks count */
+ __le32 s_free_blocks_count_lo; /* Free blocks count */
+/*10*/ __le32 s_free_inodes_count; /* Free inodes count */
+ __le32 s_first_data_block; /* First Data Block */
+ __le32 s_log_block_size; /* Block size */
+ __le32 s_log_cluster_size; /* Allocation cluster size */
+/*20*/ __le32 s_blocks_per_group; /* # Blocks per group */
+ __le32 s_clusters_per_group; /* # Clusters per group */
+ __le32 s_inodes_per_group; /* # Inodes per group */
+ __le32 s_mtime; /* Mount time */
+/*30*/ __le32 s_wtime; /* Write time */
+ __le16 s_mnt_count; /* Mount count */
+ __le16 s_max_mnt_count; /* Maximal mount count */
+ __le16 s_magic; /* Magic signature */
+ __le16 s_state; /* File system state */
+ __le16 s_errors; /* Behaviour when detecting errors */
+ __le16 s_minor_rev_level; /* minor revision level */
+/*40*/ __le32 s_lastcheck; /* time of last check */
+ __le32 s_checkinterval; /* max. time between checks */
+ __le32 s_creator_os; /* OS */
+ __le32 s_rev_level; /* Revision level */
+/*50*/ __le16 s_def_resuid; /* Default uid for reserved blocks */
+ __le16 s_def_resgid; /* Default gid for reserved blocks */
+ /*
+ * These fields are for EXT4_DYNAMIC_REV superblocks only.
+ *
+ * Note: the difference between the compatible feature set and
+ * the incompatible feature set is that if there is a bit set
+ * in the incompatible feature set that the kernel doesn't
+ * know about, it should refuse to mount the filesystem.
+ *
+ * e2fsck's requirements are more strict; if it doesn't know
+ * about a feature in either the compatible or incompatible
+ * feature set, it must abort and not try to meddle with
+ * things it doesn't understand...
+ */
+ __le32 s_first_ino; /* First non-reserved inode */
+ __le16 s_inode_size; /* size of inode structure */
+ __le16 s_block_group_nr; /* block group # of this superblock */
+ __le32 s_feature_compat; /* compatible feature set */
+/*60*/ __le32 s_feature_incompat; /* incompatible feature set */
+ __le32 s_feature_ro_compat; /* readonly-compatible feature set */
+/*68*/ __u8 s_uuid[16]; /* 128-bit uuid for volume */
+/*78*/ char s_volume_name[16]; /* volume name */
+/*88*/ char s_last_mounted[64]; /* directory where last mounted */
+/*C8*/ __le32 s_algorithm_usage_bitmap; /* For compression */
+ /*
+ * Performance hints. Directory preallocation should only
+ * happen if the EXT4_FEATURE_COMPAT_DIR_PREALLOC flag is on.
+ */
+ __u8 s_prealloc_blocks; /* Nr of blocks to try to preallocate*/
+ __u8 s_prealloc_dir_blocks; /* Nr to preallocate for dirs */
+ __le16 s_reserved_gdt_blocks; /* Per group desc for online growth */
+ /*
+ * Journaling support valid if EXT4_FEATURE_COMPAT_HAS_JOURNAL set.
+ */
+/*D0*/ __u8 s_journal_uuid[16]; /* uuid of journal superblock */
+/*E0*/ __le32 s_journal_inum; /* inode number of journal file */
+ __le32 s_journal_dev; /* device number of journal file */
+ __le32 s_last_orphan; /* start of list of inodes to delete */
+ __le32 s_hash_seed[4]; /* HTREE hash seed */
+ __u8 s_def_hash_version; /* Default hash version to use */
+ __u8 s_jnl_backup_type;
+ __le16 s_desc_size; /* size of group descriptor */
+/*100*/ __le32 s_default_mount_opts;
+ __le32 s_first_meta_bg; /* First metablock block group */
+ __le32 s_mkfs_time; /* When the filesystem was created */
+ __le32 s_jnl_blocks[17]; /* Backup of the journal inode */
+ /* 64bit support valid if EXT4_FEATURE_COMPAT_64BIT */
+/*150*/ __le32 s_blocks_count_hi; /* Blocks count */
+ __le32 s_r_blocks_count_hi; /* Reserved blocks count */
+ __le32 s_free_blocks_count_hi; /* Free blocks count */
+ __le16 s_min_extra_isize; /* All inodes have at least # bytes */
+ __le16 s_want_extra_isize; /* New inodes should reserve # bytes */
+ __le32 s_flags; /* Miscellaneous flags */
+ __le16 s_raid_stride; /* RAID stride */
+ __le16 s_mmp_update_interval; /* # seconds to wait in MMP checking */
+ __le64 s_mmp_block; /* Block for multi-mount protection */
+ __le32 s_raid_stripe_width; /* blocks on all data disks (N*stride)*/
+ __u8 s_log_groups_per_flex; /* FLEX_BG group size */
+ __u8 s_checksum_type; /* metadata checksum algorithm used */
+ __le16 s_reserved_pad;
+ __le64 s_kbytes_written; /* nr of lifetime kilobytes written */
+ __le32 s_snapshot_inum; /* Inode number of active snapshot */
+ __le32 s_snapshot_id; /* sequential ID of active snapshot */
+ __le64 s_snapshot_r_blocks_count; /* reserved blocks for active
+ snapshot's future use */
+ __le32 s_snapshot_list; /* inode number of the head of the
+ on-disk snapshot list */
+#define EXT4_S_ERR_START offsetof(struct ext4_super_block, s_error_count)
+ __le32 s_error_count; /* number of fs errors */
+ __le32 s_first_error_time; /* first time an error happened */
+ __le32 s_first_error_ino; /* inode involved in first error */
+ __le64 s_first_error_block; /* block involved of first error */
+ __u8 s_first_error_func[32]; /* function where the error happened */
+ __le32 s_first_error_line; /* line number where error happened */
+ __le32 s_last_error_time; /* most recent time of an error */
+ __le32 s_last_error_ino; /* inode involved in last error */
+ __le32 s_last_error_line; /* line number where error happened */
+ __le64 s_last_error_block; /* block involved of last error */
+ __u8 s_last_error_func[32]; /* function where the error happened */
+#define EXT4_S_ERR_END offsetof(struct ext4_super_block, s_mount_opts)
+ __u8 s_mount_opts[64];
+ __le32 s_usr_quota_inum; /* inode for tracking user quota */
+ __le32 s_grp_quota_inum; /* inode for tracking group quota */
+ __le32 s_overhead_clusters; /* overhead blocks/clusters in fs */
+ __le32 s_reserved[108]; /* Padding to the end of the block */
+ __le32 s_checksum; /* crc32c(superblock) */
+};
+/*
+ * Revision levels
+ */
+#define EXT4_GOOD_OLD_REV 0 /* The good old (original) format */
+#define EXT4_DYNAMIC_REV 1 /* V2 format w/ dynamic inode sizes */
+
+#define EXT4_CURRENT_REV EXT4_GOOD_OLD_REV
+#define EXT4_MAX_SUPP_REV EXT4_DYNAMIC_REV
+
+#define EXT4_GOOD_OLD_INODE_SIZE 128
+
+/*
+ * Feature set definitions (only the once we need for read support)
+ */
+
+#define EXT4_FEATURE_INCOMPAT_COMPRESSION 0x0001
+#define EXT4_FEATURE_INCOMPAT_FILETYPE 0x0002
+#define EXT4_FEATURE_INCOMPAT_RECOVER 0x0004 /* Needs recovery */
+#define EXT4_FEATURE_INCOMPAT_JOURNAL_DEV 0x0008 /* Journal device */
+#define EXT4_FEATURE_INCOMPAT_META_BG 0x0010
+#define EXT4_FEATURE_INCOMPAT_EXTENTS 0x0040 /* extents support */
+#define EXT4_FEATURE_INCOMPAT_64BIT 0x0080
+#define EXT4_FEATURE_INCOMPAT_MMP 0x0100
+#define EXT4_FEATURE_INCOMPAT_FLEX_BG 0x0200
+#define EXT4_FEATURE_INCOMPAT_EA_INODE 0x0400 /* EA in inode */
+#define EXT4_FEATURE_INCOMPAT_DIRDATA 0x1000 /* data in dirent */
+#define EXT4_FEATURE_INCOMPAT_BG_USE_META_CSUM 0x2000 /* use crc32c for bg */
+#define EXT4_FEATURE_INCOMPAT_LARGEDIR 0x4000 /* >2GB or 3-lvl htree */
+#define EXT4_FEATURE_INCOMPAT_INLINEDATA 0x8000 /* data in inode */
+
+#define EXT4_FEATURE_INCOMPAT_SUPP (EXT4_FEATURE_INCOMPAT_FILETYPE| \
+ EXT4_FEATURE_INCOMPAT_RECOVER| \
+ EXT4_FEATURE_INCOMPAT_META_BG| \
+ EXT4_FEATURE_INCOMPAT_EXTENTS| \
+ EXT4_FEATURE_INCOMPAT_64BIT| \
+ EXT4_FEATURE_INCOMPAT_FLEX_BG| \
+ EXT4_FEATURE_INCOMPAT_MMP)
+
+/*
+ * Structure of a directory entry
+ */
+#define EXT4_NAME_LEN 255
+
+struct ext4_dir_entry {
+ __le32 inode; /* Inode number */
+ __le16 rec_len; /* Directory entry length */
+ __u8 name_len; /* Name length */
+ __u8 file_type;
+ char name[EXT4_NAME_LEN]; /* File name */
+};
+// NOTE: The original Linux kernel header defines ext4_dir_entry with the original
+// layout and ext4_dir_entry_2 with the revised layout. We simply use the revised one.
+
+/*
+ * Ext2 directory file types. Only the low 3 bits are used. The
+ * other bits are reserved for now.
+ */
+enum {
+ EXT4_FT_UNKNOWN,
+ EXT4_FT_REG_FILE,
+ EXT4_FT_DIR,
+ EXT4_FT_CHRDEV,
+ EXT4_FT_BLKDEV,
+ EXT4_FT_FIFO,
+ EXT4_FT_SOCK,
+ EXT4_FT_SYMLINK,
+ EXT4_FT_MAX
+};
+
+
+#endif