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freebsd-skq/sys/fs/ext2fs/ext2fs.h
pfg 0b111bdfcb Add read-only support for extents in ext2fs. 
Basic support for extents was implemented by Zheng Liu as part
of his Google Summer of Code in 2010. This support is read-only
at this time.

In addition to extents we also support the huge_file extension
for read-only purposes. This works nicely with the additional
support for birthtime/nanosec timestamps and dir_index that
have been added lately.

The implementation may not work for all ext4 filesystems as
it doesn't support some features that are being enabled by
default on recent linux like flex_bg. Nevertheless, the feature
should be very useful for migration or simple access in
filesystems that have been converted from ext2/3 or don't use
incompatible features.

Special thanks to Zheng Liu for his dedication and continued
work to support ext2 in FreeBSD.

Submitted by:	Zheng Liu (lz@)
Reviewed by:	Mike Ma, Christoph Mallon (previous version)
Sponsored by:	Google Inc.
MFC after:	3 weeks
2013-08-12 21:34:48 +00:00

293 lines
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/*-
* modified for EXT2FS support in Lites 1.1
*
* Aug 1995, Godmar Back (gback@cs.utah.edu)
* University of Utah, Department of Computer Science
*
* $FreeBSD$
*/
/*-
* Copyright (c) 2009 Aditya Sarawgi
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
*
*/
#ifndef _FS_EXT2FS_EXT2FS_H_
#define _FS_EXT2FS_EXT2FS_H_
#include <sys/types.h>
/*
* Super block for an ext2fs file system.
*/
struct ext2fs {
uint32_t e2fs_icount; /* Inode count */
uint32_t e2fs_bcount; /* blocks count */
uint32_t e2fs_rbcount; /* reserved blocks count */
uint32_t e2fs_fbcount; /* free blocks count */
uint32_t e2fs_ficount; /* free inodes count */
uint32_t e2fs_first_dblock; /* first data block */
uint32_t e2fs_log_bsize; /* block size = 1024*(2^e2fs_log_bsize) */
uint32_t e2fs_log_fsize; /* fragment size */
uint32_t e2fs_bpg; /* blocks per group */
uint32_t e2fs_fpg; /* frags per group */
uint32_t e2fs_ipg; /* inodes per group */
uint32_t e2fs_mtime; /* mount time */
uint32_t e2fs_wtime; /* write time */
uint16_t e2fs_mnt_count; /* mount count */
uint16_t e2fs_max_mnt_count; /* max mount count */
uint16_t e2fs_magic; /* magic number */
uint16_t e2fs_state; /* file system state */
uint16_t e2fs_beh; /* behavior on errors */
uint16_t e2fs_minrev; /* minor revision level */
uint32_t e2fs_lastfsck; /* time of last fsck */
uint32_t e2fs_fsckintv; /* max time between fscks */
uint32_t e2fs_creator; /* creator OS */
uint32_t e2fs_rev; /* revision level */
uint16_t e2fs_ruid; /* default uid for reserved blocks */
uint16_t e2fs_rgid; /* default gid for reserved blocks */
/* EXT2_DYNAMIC_REV superblocks */
uint32_t e2fs_first_ino; /* first non-reserved inode */
uint16_t e2fs_inode_size; /* size of inode structure */
uint16_t e2fs_block_group_nr; /* block grp number of this sblk*/
uint32_t e2fs_features_compat; /* compatible feature set */
uint32_t e2fs_features_incompat; /* incompatible feature set */
uint32_t e2fs_features_rocompat; /* RO-compatible feature set */
uint8_t e2fs_uuid[16]; /* 128-bit uuid for volume */
char e2fs_vname[16]; /* volume name */
char e2fs_fsmnt[64]; /* name mounted on */
uint32_t e2fs_algo; /* For compression */
uint8_t e2fs_prealloc; /* # of blocks for old prealloc */
uint8_t e2fs_dir_prealloc; /* # of blocks for old prealloc dirs */
uint16_t e2fs_reserved_ngdb; /* # of reserved gd blocks for resize */
char e3fs_journal_uuid[16]; /* uuid of journal superblock */
uint32_t e3fs_journal_inum; /* inode number of journal file */
uint32_t e3fs_journal_dev; /* device number of journal file */
uint32_t e3fs_last_orphan; /* start of list of inodes to delete */
uint32_t e3fs_hash_seed[4]; /* HTREE hash seed */
char e3fs_def_hash_version; /* Default hash version to use */
char e3fs_reserved_char_pad;
uint32_t e3fs_default_mount_opts;
uint32_t e3fs_first_meta_bg; /* First metablock block group */
uint32_t e3fs_mkfs_time; /* when the fs was created */
uint32_t e3fs_jnl_blks[17]; /* backup of the journal inode */
uint32_t e4fs_bcount_hi; /* block count */
uint32_t e4fs_rbcount_hi; /* reserved blocks count */
uint32_t e4fs_fbcount_hi; /* free blocks count */
uint16_t e4fs_min_extra_isize;/* all inodes have at least some bytes */
uint16_t e4fs_want_extra_isize; /* inodes must reserve some bytes */
uint32_t e4fs_flags; /* miscellaneous flags */
uint16_t e4fs_raid_stride; /* RAID stride */
uint16_t e4fs_mmpintv; /* number of seconds to wait in MMP checking */
uint64_t e4fs_mmpblk; /* block for multi-mount protection */
uint32_t e4fs_raid_stripe_wid;/* blocks on all data disks (N * stride) */
uint8_t e4fs_log_gpf; /* FLEX_BG group size */
uint8_t e4fs_char_pad2;
uint16_t e4fs_pad;
uint32_t reserved2[162]; /* Padding to the end of the block */
};
/*
* The path name on which the file system is mounted is maintained
* in fs_fsmnt. MAXMNTLEN defines the amount of space allocated in
* the super block for this name.
*/
#define MAXMNTLEN 512
/*
* In-Memory Superblock
*/
struct m_ext2fs {
struct ext2fs * e2fs;
char e2fs_fsmnt[MAXMNTLEN];/* name mounted on */
char e2fs_ronly; /* mounted read-only flag */
char e2fs_fmod; /* super block modified flag */
uint32_t e2fs_bsize; /* Block size */
uint32_t e2fs_bshift; /* calc of logical block no */
uint32_t e2fs_bpg; /* Number of blocks per group */
int64_t e2fs_qbmask; /* = s_blocksize -1 */
uint32_t e2fs_fsbtodb; /* Shift to get disk block */
uint32_t e2fs_ipg; /* Number of inodes per group */
uint32_t e2fs_ipb; /* Number of inodes per block */
uint32_t e2fs_itpg; /* Number of inode table per group */
uint32_t e2fs_fsize; /* Size of fragments per block */
uint32_t e2fs_fpb; /* Number of fragments per block */
uint32_t e2fs_fpg; /* Number of fragments per group */
uint32_t e2fs_gdbcount; /* Number of group descriptors */
uint32_t e2fs_gcount; /* Number of groups */
uint32_t e2fs_isize; /* Size of inode */
uint32_t e2fs_total_dir; /* Total number of directories */
uint8_t *e2fs_contigdirs; /* (u) # of contig. allocated dirs */
char e2fs_wasvalid; /* valid at mount time */
off_t e2fs_maxfilesize;
struct ext2_gd *e2fs_gd; /* Group Descriptors */
int32_t e2fs_contigsumsize; /* size of cluster summary array */
int32_t *e2fs_maxcluster; /* max cluster in each cyl group */
struct csum *e2fs_clustersum; /* cluster summary in each cyl group */
int32_t e2fs_uhash; /* 3 if hash should be signed, 0 if not */
};
/* cluster summary information */
struct csum {
int8_t cs_init; /* cluster summary has been initialized */
int32_t *cs_sum; /* cluster summary array */
};
/*
* The second extended file system magic number
*/
#define E2FS_MAGIC 0xEF53
/*
* Revision levels
*/
#define E2FS_REV0 0 /* The good old (original) format */
#define E2FS_REV1 1 /* V2 format w/ dynamic inode sizes */
#define E2FS_REV0_INODE_SIZE 128
/*
* compatible/incompatible features
*/
#define EXT2F_COMPAT_PREALLOC 0x0001
#define EXT2F_COMPAT_HASJOURNAL 0x0004
#define EXT2F_COMPAT_RESIZE 0x0010
#define EXT2F_COMPAT_DIRHASHINDEX 0x0020
#define EXT2F_ROCOMPAT_SPARSESUPER 0x0001
#define EXT2F_ROCOMPAT_LARGEFILE 0x0002
#define EXT2F_ROCOMPAT_BTREE_DIR 0x0004
#define EXT2F_ROCOMPAT_HUGE_FILE 0x0008
#define EXT2F_ROCOMPAT_GDT_CSUM 0x0010
#define EXT2F_ROCOMPAT_DIR_NLINK 0x0020
#define EXT2F_ROCOMPAT_EXTRA_ISIZE 0x0040
#define EXT2F_INCOMPAT_COMP 0x0001
#define EXT2F_INCOMPAT_FTYPE 0x0002
#define EXT2F_INCOMPAT_META_BG 0x0010
#define EXT2F_INCOMPAT_EXTENTS 0x0040
#define EXT2F_INCOMPAT_64BIT 0x0080
#define EXT2F_INCOMPAT_MMP 0x0100
#define EXT2F_INCOMPAT_FLEX_BG 0x0200
/*
* Features supported in this implementation
*
* We support the following REV1 features:
* - EXT2F_ROCOMPAT_SPARSESUPER
* - EXT2F_ROCOMPAT_LARGEFILE
* - EXT2F_INCOMPAT_FTYPE
*
* We partially (read-only) support the following EXT4 features:
* - EXT2F_ROCOMPAT_HUGE_FILE
* - EXT2F_ROCOMPAT_EXTRA_ISIZE
* - EXT2F_INCOMPAT_EXTENTS
*/
#define EXT2F_COMPAT_SUPP 0x0000
#define EXT2F_ROCOMPAT_SUPP (EXT2F_ROCOMPAT_SPARSESUPER | \
EXT2F_ROCOMPAT_LARGEFILE | \
EXT2F_ROCOMPAT_EXTRA_ISIZE)
#define EXT2F_INCOMPAT_SUPP (EXT2F_INCOMPAT_FTYPE | \
EXT2F_INCOMPAT_EXTENTS)
/* Assume that user mode programs are passing in an ext2fs superblock, not
* a kernel struct super_block. This will allow us to call the feature-test
* macros from user land. */
#define EXT2_SB(sb) (sb)
/*
* Feature set definitions
*/
#define EXT2_HAS_COMPAT_FEATURE(sb,mask) \
( EXT2_SB(sb)->e2fs->e2fs_features_compat & htole32(mask) )
#define EXT2_HAS_RO_COMPAT_FEATURE(sb,mask) \
( EXT2_SB(sb)->e2fs->e2fs_features_rocompat & htole32(mask) )
#define EXT2_HAS_INCOMPAT_FEATURE(sb,mask) \
( EXT2_SB(sb)->e2fs->e2fs_features_incompat & htole32(mask) )
/*
* File clean flags
*/
#define E2FS_ISCLEAN 0x0001 /* Unmounted cleanly */
#define E2FS_ERRORS 0x0002 /* Errors detected */
/*
* Filesystem miscellaneous flags
*/
#define E2FS_SIGNED_HASH 0x0001
#define E2FS_UNSIGNED_HASH 0x0002
/* ext2 file system block group descriptor */
struct ext2_gd {
uint32_t ext2bgd_b_bitmap; /* blocks bitmap block */
uint32_t ext2bgd_i_bitmap; /* inodes bitmap block */
uint32_t ext2bgd_i_tables; /* inodes table block */
uint16_t ext2bgd_nbfree; /* number of free blocks */
uint16_t ext2bgd_nifree; /* number of free inodes */
uint16_t ext2bgd_ndirs; /* number of directories */
uint16_t ext4bgd_flags; /* block group flags */
uint32_t ext4bgd_x_bitmap; /* snapshot exclusion bitmap loc. */
uint16_t ext4bgd_b_bmap_csum; /* block bitmap checksum */
uint16_t ext4bgd_i_bmap_csum; /* inode bitmap checksum */
uint16_t ext4bgd_i_unused; /* unused inode count */
uint16_t ext4bgd_csum; /* group descriptor checksum */
};
/* EXT2FS metadatas are stored in little-endian byte order. These macros
* helps reading these metadatas
*/
#define e2fs_cgload(old, new, size) memcpy((new), (old), (size));
#define e2fs_cgsave(old, new, size) memcpy((new), (old), (size));
/*
* Macro-instructions used to manage several block sizes
*/
#define EXT2_MAX_BLOCK_SIZE 4096
#define EXT2_MIN_BLOCK_LOG_SIZE 10
#define EXT2_BLOCK_SIZE(s) ((s)->e2fs_bsize)
#define EXT2_ADDR_PER_BLOCK(s) (EXT2_BLOCK_SIZE(s) / sizeof(uint32_t))
#define EXT2_INODE_SIZE(s) (EXT2_SB(s)->e2fs_isize)
/*
* Macro-instructions used to manage fragments
*/
#define EXT2_MIN_FRAG_SIZE 1024
#define EXT2_MAX_FRAG_SIZE 4096
#define EXT2_MIN_FRAG_LOG_SIZE 10
#define EXT2_FRAG_SIZE(s) (EXT2_SB(s)->e2fs_fsize)
#define EXT2_FRAGS_PER_BLOCK(s) (EXT2_SB(s)->e2fs_fpb)
/*
* Macro-instructions used to manage group descriptors
*/
#define EXT2_BLOCKS_PER_GROUP(s) (EXT2_SB(s)->e2fs_bpg)
#endif /* !_FS_EXT2FS_EXT2FS_H_ */
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