970d95ecd5
- fix panic on truncating files with holes; - remove block-based readahead, to match MFS. Change-Id: I385552f8019e9c013a6cb937bcc8e4e7181a4a50
128 lines
6.0 KiB
C
128 lines
6.0 KiB
C
/* Super block table. The root file system and every mounted file system
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* has an entry here. The entry holds information about the sizes of the bit
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* maps and inodes.
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*
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* A super_block slot is free if s_dev == NO_DEV.
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*
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*/
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#ifndef EXT2_SUPER_H
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#define EXT2_SUPER_H
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/* super_block (on-disk part) was taken from linux/include/linux/ext2_fs.h */
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EXTERN struct super_block {
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u32_t s_inodes_count; /* Inodes count */
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u32_t s_blocks_count; /* Blocks count */
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u32_t s_r_blocks_count; /* Reserved blocks count */
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u32_t s_free_blocks_count; /* Free blocks count */
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u32_t s_free_inodes_count; /* Free inodes count */
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u32_t s_first_data_block; /* First Data Block */
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u32_t s_log_block_size; /* Block size */
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u32_t s_log_frag_size; /* Fragment size */
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u32_t s_blocks_per_group; /* # Blocks per group */
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u32_t s_frags_per_group; /* # Fragments per group */
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u32_t s_inodes_per_group; /* # Inodes per group */
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u32_t s_mtime; /* Mount time */
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u32_t s_wtime; /* Write time */
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u16_t s_mnt_count; /* Mount count */
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u16_t s_max_mnt_count; /* Maximal mount count */
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u16_t s_magic; /* Magic signature */
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u16_t s_state; /* File system state */
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u16_t s_errors; /* Behaviour when detecting errors */
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u16_t s_minor_rev_level; /* minor revision level */
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u32_t s_lastcheck; /* time of last check */
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u32_t s_checkinterval; /* max. time between checks */
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u32_t s_creator_os; /* OS */
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u32_t s_rev_level; /* Revision level */
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u16_t s_def_resuid; /* Default uid for reserved blocks */
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u16_t s_def_resgid; /* Default gid for reserved blocks */
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/*
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* These fields are for EXT2_DYNAMIC_REV superblocks only.
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*
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* Note: the difference between the compatible feature set and
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* the incompatible feature set is that if there is a bit set
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* in the incompatible feature set that the kernel doesn't
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* know about, it should refuse to mount the filesystem.
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*
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* e2fsck's requirements are more strict; if it doesn't know
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* about a feature in either the compatible or incompatible
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* feature set, it must abort and not try to meddle with
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* things it doesn't understand...
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*/
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u32_t s_first_ino; /* First non-reserved inode */
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u16_t s_inode_size; /* size of inode structure */
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u16_t s_block_group_nr; /* block group # of this superblock */
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u32_t s_feature_compat; /* compatible feature set */
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u32_t s_feature_incompat; /* incompatible feature set */
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u32_t s_feature_ro_compat; /* readonly-compatible feature set */
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u8_t s_uuid[16]; /* 128-bit uuid for volume */
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char s_volume_name[16]; /* volume name */
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char s_last_mounted[64]; /* directory where last mounted */
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u32_t s_algorithm_usage_bitmap; /* For compression */
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/*
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* Performance hints. Directory preallocation should only
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* happen if the EXT2_COMPAT_PREALLOC flag is on.
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*/
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u8_t s_prealloc_blocks; /* Nr of blocks to try to preallocate*/
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u8_t s_prealloc_dir_blocks; /* Nr to preallocate for dirs */
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u16_t s_padding1;
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/*
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* Journaling support valid if EXT3_FEATURE_COMPAT_HAS_JOURNAL set.
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*/
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u8_t s_journal_uuid[16]; /* uuid of journal superblock */
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u32_t s_journal_inum; /* inode number of journal file */
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u32_t s_journal_dev; /* device number of journal file */
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u32_t s_last_orphan; /* start of list of inodes to delete */
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u32_t s_hash_seed[4]; /* HTREE hash seed */
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u8_t s_def_hash_version; /* Default hash version to use */
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u8_t s_reserved_char_pad;
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u16_t s_reserved_word_pad;
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u32_t s_default_mount_opts;
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u32_t s_first_meta_bg; /* First metablock block group */
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u32_t s_reserved[190]; /* Padding to the end of the block */
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/* The following items are only used when the super_block is in memory. */
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u32_t s_inodes_per_block; /* Number of inodes per block */
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u32_t s_itb_per_group; /* Number of inode table blocks per group */
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u32_t s_gdb_count; /* Number of group descriptor blocks */
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u32_t s_desc_per_block; /* Number of group descriptors per block */
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u32_t s_groups_count; /* Number of groups in the fs */
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u8_t s_blocksize_bits; /* Used to calculate offsets
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* (e.g. inode block),
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* always s_log_block_size+10.
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*/
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struct group_desc *s_group_desc; /* Group descriptors read into RAM */
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u16_t s_block_size; /* block size in bytes. */
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u16_t s_sectors_in_block; /* s_block_size / 512 */
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u32_t s_max_size; /* maximum file size on this device */
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dev_t s_dev; /* whose super block is this? */
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int s_rd_only; /* set to 1 if file sys mounted read only */
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block_t s_bsearch; /* all data blocks below this block are in use*/
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int s_igsearch; /* all groups below this one have no free inodes */
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u32_t s_dirs_counter;
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} *superblock, *ondisk_superblock;
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/* Structure of a blocks group descriptor.
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* On disk stored in little endian format.
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*/
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struct group_desc
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{
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u32_t block_bitmap; /* Blocks bitmap block */
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u32_t inode_bitmap; /* Inodes bitmap block */
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u32_t inode_table; /* Inodes table block */
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u16_t free_blocks_count; /* Free blocks count */
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u16_t free_inodes_count; /* Free inodes count */
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u16_t used_dirs_count; /* Directories count */
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u16_t pad;
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u32_t reserved[3];
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};
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#define IMAP 0 /* operating on the inode bit map */
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#define BMAP 1 /* operating on the block bit map */
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#define IMAPD 2 /* operating on the inode bit map, inode is dir */
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#endif /* EXT2_SUPER_H */
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