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Diffstat (limited to 'fs/xfs/xfs_dir2_format.h')
| -rw-r--r-- | fs/xfs/xfs_dir2_format.h | 597 |
1 files changed, 597 insertions, 0 deletions
diff --git a/fs/xfs/xfs_dir2_format.h b/fs/xfs/xfs_dir2_format.h new file mode 100644 index 000000000000..07270981f48f --- /dev/null +++ b/fs/xfs/xfs_dir2_format.h @@ -0,0 +1,597 @@ +/* + * Copyright (c) 2000-2001,2005 Silicon Graphics, Inc. + * All Rights Reserved. + * + * 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. + * + * This program is distributed in the hope that it would 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 the Free Software Foundation, + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA + */ +#ifndef __XFS_DIR2_FORMAT_H__ +#define __XFS_DIR2_FORMAT_H__ + +/* + * Directory version 2. + * + * There are 4 possible formats: + * - shortform - embedded into the inode + * - single block - data with embedded leaf at the end + * - multiple data blocks, single leaf+freeindex block + * - data blocks, node and leaf blocks (btree), freeindex blocks + * + * Note: many node blocks structures and constants are shared with the attr + * code and defined in xfs_da_btree.h. + */ + +#define XFS_DIR2_BLOCK_MAGIC 0x58443242 /* XD2B: single block dirs */ +#define XFS_DIR2_DATA_MAGIC 0x58443244 /* XD2D: multiblock dirs */ +#define XFS_DIR2_FREE_MAGIC 0x58443246 /* XD2F: free index blocks */ + +/* + * Byte offset in data block and shortform entry. + */ +typedef __uint16_t xfs_dir2_data_off_t; +#define NULLDATAOFF 0xffffU +typedef uint xfs_dir2_data_aoff_t; /* argument form */ + +/* + * Normalized offset (in a data block) of the entry, really xfs_dir2_data_off_t. + * Only need 16 bits, this is the byte offset into the single block form. + */ +typedef struct { __uint8_t i[2]; } __arch_pack xfs_dir2_sf_off_t; + +/* + * Offset in data space of a data entry. + */ +typedef __uint32_t xfs_dir2_dataptr_t; +#define XFS_DIR2_MAX_DATAPTR ((xfs_dir2_dataptr_t)0xffffffff) +#define XFS_DIR2_NULL_DATAPTR ((xfs_dir2_dataptr_t)0) + +/* + * Byte offset in a directory. + */ +typedef xfs_off_t xfs_dir2_off_t; + +/* + * Directory block number (logical dirblk in file) + */ +typedef __uint32_t xfs_dir2_db_t; + +/* + * Inode number stored as 8 8-bit values. + */ +typedef struct { __uint8_t i[8]; } xfs_dir2_ino8_t; + +/* + * Inode number stored as 4 8-bit values. + * Works a lot of the time, when all the inode numbers in a directory + * fit in 32 bits. + */ +typedef struct { __uint8_t i[4]; } xfs_dir2_ino4_t; + +typedef union { + xfs_dir2_ino8_t i8; + xfs_dir2_ino4_t i4; +} xfs_dir2_inou_t; +#define XFS_DIR2_MAX_SHORT_INUM ((xfs_ino_t)0xffffffffULL) + +/* + * Directory layout when stored internal to an inode. + * + * Small directories are packed as tightly as possible so as to fit into the + * literal area of the inode. These "shortform" directories consist of a + * single xfs_dir2_sf_hdr header followed by zero or more xfs_dir2_sf_entry + * structures. Due the different inode number storage size and the variable + * length name field in the xfs_dir2_sf_entry all these structure are + * variable length, and the accessors in this file should be used to iterate + * over them. + */ +typedef struct xfs_dir2_sf_hdr { + __uint8_t count; /* count of entries */ + __uint8_t i8count; /* count of 8-byte inode #s */ + xfs_dir2_inou_t parent; /* parent dir inode number */ +} __arch_pack xfs_dir2_sf_hdr_t; + +typedef struct xfs_dir2_sf_entry { + __u8 namelen; /* actual name length */ + xfs_dir2_sf_off_t offset; /* saved offset */ + __u8 name[]; /* name, variable size */ + /* + * A xfs_dir2_ino8_t or xfs_dir2_ino4_t follows here, at a + * variable offset after the name. + */ +} __arch_pack xfs_dir2_sf_entry_t; + +static inline int xfs_dir2_sf_hdr_size(int i8count) +{ + return sizeof(struct xfs_dir2_sf_hdr) - + (i8count == 0) * + (sizeof(xfs_dir2_ino8_t) - sizeof(xfs_dir2_ino4_t)); +} + +static inline xfs_dir2_data_aoff_t +xfs_dir2_sf_get_offset(xfs_dir2_sf_entry_t *sfep) +{ + return get_unaligned_be16(&sfep->offset.i); +} + +static inline void +xfs_dir2_sf_put_offset(xfs_dir2_sf_entry_t *sfep, xfs_dir2_data_aoff_t off) +{ + put_unaligned_be16(off, &sfep->offset.i); +} + +static inline int +xfs_dir2_sf_entsize(struct xfs_dir2_sf_hdr *hdr, int len) +{ + return sizeof(struct xfs_dir2_sf_entry) + /* namelen + offset */ + len + /* name */ + (hdr->i8count ? /* ino */ + sizeof(xfs_dir2_ino8_t) : + sizeof(xfs_dir2_ino4_t)); +} + +static inline struct xfs_dir2_sf_entry * +xfs_dir2_sf_firstentry(struct xfs_dir2_sf_hdr *hdr) +{ + return (struct xfs_dir2_sf_entry *) + ((char *)hdr + xfs_dir2_sf_hdr_size(hdr->i8count)); +} + +static inline struct xfs_dir2_sf_entry * +xfs_dir2_sf_nextentry(struct xfs_dir2_sf_hdr *hdr, + struct xfs_dir2_sf_entry *sfep) +{ + return (struct xfs_dir2_sf_entry *) + ((char *)sfep + xfs_dir2_sf_entsize(hdr, sfep->namelen)); +} + + +/* + * Data block structures. + * + * A pure data block looks like the following drawing on disk: + * + * +-------------------------------------------------+ + * | xfs_dir2_data_hdr_t | + * +-------------------------------------------------+ + * | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t | + * | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t | + * | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t | + * | ... | + * +-------------------------------------------------+ + * | unused space | + * +-------------------------------------------------+ + * + * As all the entries are variable size structures the accessors below should + * be used to iterate over them. + * + * In addition to the pure data blocks for the data and node formats, + * most structures are also used for the combined data/freespace "block" + * format below. + */ + +#define XFS_DIR2_DATA_ALIGN_LOG 3 /* i.e., 8 bytes */ +#define XFS_DIR2_DATA_ALIGN (1 << XFS_DIR2_DATA_ALIGN_LOG) +#define XFS_DIR2_DATA_FREE_TAG 0xffff +#define XFS_DIR2_DATA_FD_COUNT 3 + +/* + * Directory address space divided into sections, + * spaces separated by 32GB. + */ +#define XFS_DIR2_SPACE_SIZE (1ULL << (32 + XFS_DIR2_DATA_ALIGN_LOG)) +#define XFS_DIR2_DATA_SPACE 0 +#define XFS_DIR2_DATA_OFFSET (XFS_DIR2_DATA_SPACE * XFS_DIR2_SPACE_SIZE) +#define XFS_DIR2_DATA_FIRSTDB(mp) \ + xfs_dir2_byte_to_db(mp, XFS_DIR2_DATA_OFFSET) + +/* + * Offsets of . and .. in data space (always block 0) + */ +#define XFS_DIR2_DATA_DOT_OFFSET \ + ((xfs_dir2_data_aoff_t)sizeof(struct xfs_dir2_data_hdr)) +#define XFS_DIR2_DATA_DOTDOT_OFFSET \ + (XFS_DIR2_DATA_DOT_OFFSET + xfs_dir2_data_entsize(1)) +#define XFS_DIR2_DATA_FIRST_OFFSET \ + (XFS_DIR2_DATA_DOTDOT_OFFSET + xfs_dir2_data_entsize(2)) + +/* + * Describe a free area in the data block. + * + * The freespace will be formatted as a xfs_dir2_data_unused_t. + */ +typedef struct xfs_dir2_data_free { + __be16 offset; /* start of freespace */ + __be16 length; /* length of freespace */ +} xfs_dir2_data_free_t; + +/* + * Header for the data blocks. + * + * The code knows that XFS_DIR2_DATA_FD_COUNT is 3. + */ +typedef struct xfs_dir2_data_hdr { + __be32 magic; /* XFS_DIR2_DATA_MAGIC or */ + /* XFS_DIR2_BLOCK_MAGIC */ + xfs_dir2_data_free_t bestfree[XFS_DIR2_DATA_FD_COUNT]; +} xfs_dir2_data_hdr_t; + +/* + * Active entry in a data block. + * + * Aligned to 8 bytes. After the variable length name field there is a + * 2 byte tag field, which can be accessed using xfs_dir2_data_entry_tag_p. + */ +typedef struct xfs_dir2_data_entry { + __be64 inumber; /* inode number */ + __u8 namelen; /* name length */ + __u8 name[]; /* name bytes, no null */ + /* __be16 tag; */ /* starting offset of us */ +} xfs_dir2_data_entry_t; + +/* + * Unused entry in a data block. + * + * Aligned to 8 bytes. Tag appears as the last 2 bytes and must be accessed + * using xfs_dir2_data_unused_tag_p. + */ +typedef struct xfs_dir2_data_unused { + __be16 freetag; /* XFS_DIR2_DATA_FREE_TAG */ + __be16 length; /* total free length */ + /* variable offset */ + __be16 tag; /* starting offset of us */ +} xfs_dir2_data_unused_t; + +/* + * Size of a data entry. + */ +static inline int xfs_dir2_data_entsize(int n) +{ + return (int)roundup(offsetof(struct xfs_dir2_data_entry, name[0]) + n + + (uint)sizeof(xfs_dir2_data_off_t), XFS_DIR2_DATA_ALIGN); +} + +/* + * Pointer to an entry's tag word. + */ +static inline __be16 * +xfs_dir2_data_entry_tag_p(struct xfs_dir2_data_entry *dep) +{ + return (__be16 *)((char *)dep + + xfs_dir2_data_entsize(dep->namelen) - sizeof(__be16)); +} + +/* + * Pointer to a freespace's tag word. + */ +static inline __be16 * +xfs_dir2_data_unused_tag_p(struct xfs_dir2_data_unused *dup) +{ + return (__be16 *)((char *)dup + + be16_to_cpu(dup->length) - sizeof(__be16)); +} + +/* + * Leaf block structures. + * + * A pure leaf block looks like the following drawing on disk: + * + * +---------------------------+ + * | xfs_dir2_leaf_hdr_t | + * +---------------------------+ + * | xfs_dir2_leaf_entry_t | + * | xfs_dir2_leaf_entry_t | + * | xfs_dir2_leaf_entry_t | + * | xfs_dir2_leaf_entry_t | + * | ... | + * +---------------------------+ + * | xfs_dir2_data_off_t | + * | xfs_dir2_data_off_t | + * | xfs_dir2_data_off_t | + * | ... | + * +---------------------------+ + * | xfs_dir2_leaf_tail_t | + * +---------------------------+ + * + * The xfs_dir2_data_off_t members (bests) and tail are at the end of the block + * for single-leaf (magic = XFS_DIR2_LEAF1_MAGIC) blocks only, but not present + * for directories with separate leaf nodes and free space blocks + * (magic = XFS_DIR2_LEAFN_MAGIC). + * + * As all the entries are variable size structures the accessors below should + * be used to iterate over them. + */ + +/* + * Offset of the leaf/node space. First block in this space + * is the btree root. + */ +#define XFS_DIR2_LEAF_SPACE 1 +#define XFS_DIR2_LEAF_OFFSET (XFS_DIR2_LEAF_SPACE * XFS_DIR2_SPACE_SIZE) +#define XFS_DIR2_LEAF_FIRSTDB(mp) \ + xfs_dir2_byte_to_db(mp, XFS_DIR2_LEAF_OFFSET) + +/* + * Leaf block header. + */ +typedef struct xfs_dir2_leaf_hdr { + xfs_da_blkinfo_t info; /* header for da routines */ + __be16 count; /* count of entries */ + __be16 stale; /* count of stale entries */ +} xfs_dir2_leaf_hdr_t; + +/* + * Leaf block entry. + */ +typedef struct xfs_dir2_leaf_entry { + __be32 hashval; /* hash value of name */ + __be32 address; /* address of data entry */ +} xfs_dir2_leaf_entry_t; + +/* + * Leaf block tail. + */ +typedef struct xfs_dir2_leaf_tail { + __be32 bestcount; +} xfs_dir2_leaf_tail_t; + +/* + * Leaf block. + */ +typedef struct xfs_dir2_leaf { + xfs_dir2_leaf_hdr_t hdr; /* leaf header */ + xfs_dir2_leaf_entry_t ents[]; /* entries */ +} xfs_dir2_leaf_t; + +/* + * DB blocks here are logical directory block numbers, not filesystem blocks. + */ + +static inline int xfs_dir2_max_leaf_ents(struct xfs_mount *mp) +{ + return (mp->m_dirblksize - (uint)sizeof(struct xfs_dir2_leaf_hdr)) / + (uint)sizeof(struct xfs_dir2_leaf_entry); +} + +/* + * Get address of the bestcount field in the single-leaf block. + */ +static inline struct xfs_dir2_leaf_tail * +xfs_dir2_leaf_tail_p(struct xfs_mount *mp, struct xfs_dir2_leaf *lp) +{ + return (struct xfs_dir2_leaf_tail *) + ((char *)lp + mp->m_dirblksize - + sizeof(struct xfs_dir2_leaf_tail)); +} + +/* + * Get address of the bests array in the single-leaf block. + */ +static inline __be16 * +xfs_dir2_leaf_bests_p(struct xfs_dir2_leaf_tail *ltp) +{ + return (__be16 *)ltp - be32_to_cpu(ltp->bestcount); +} + +/* + * Convert dataptr to byte in file space + */ +static inline xfs_dir2_off_t +xfs_dir2_dataptr_to_byte(struct xfs_mount *mp, xfs_dir2_dataptr_t dp) +{ + return (xfs_dir2_off_t)dp << XFS_DIR2_DATA_ALIGN_LOG; +} + +/* + * Convert byte in file space to dataptr. It had better be aligned. + */ +static inline xfs_dir2_dataptr_t +xfs_dir2_byte_to_dataptr(struct xfs_mount *mp, xfs_dir2_off_t by) +{ + return (xfs_dir2_dataptr_t)(by >> XFS_DIR2_DATA_ALIGN_LOG); +} + +/* + * Convert byte in space to (DB) block + */ +static inline xfs_dir2_db_t +xfs_dir2_byte_to_db(struct xfs_mount *mp, xfs_dir2_off_t by) +{ + return (xfs_dir2_db_t) + (by >> (mp->m_sb.sb_blocklog + mp->m_sb.sb_dirblklog)); +} + +/* + * Convert dataptr to a block number + */ +static inline xfs_dir2_db_t +xfs_dir2_dataptr_to_db(struct xfs_mount *mp, xfs_dir2_dataptr_t dp) +{ + return xfs_dir2_byte_to_db(mp, xfs_dir2_dataptr_to_byte(mp, dp)); +} + +/* + * Convert byte in space to offset in a block + */ +static inline xfs_dir2_data_aoff_t +xfs_dir2_byte_to_off(struct xfs_mount *mp, xfs_dir2_off_t by) +{ + return (xfs_dir2_data_aoff_t)(by & + ((1 << (mp->m_sb.sb_blocklog + mp->m_sb.sb_dirblklog)) - 1)); +} + +/* + * Convert dataptr to a byte offset in a block + */ +static inline xfs_dir2_data_aoff_t +xfs_dir2_dataptr_to_off(struct xfs_mount *mp, xfs_dir2_dataptr_t dp) +{ + return xfs_dir2_byte_to_off(mp, xfs_dir2_dataptr_to_byte(mp, dp)); +} + +/* + * Convert block and offset to byte in space + */ +static inline xfs_dir2_off_t +xfs_dir2_db_off_to_byte(struct xfs_mount *mp, xfs_dir2_db_t db, + xfs_dir2_data_aoff_t o) +{ + return ((xfs_dir2_off_t)db << + (mp->m_sb.sb_blocklog + mp->m_sb.sb_dirblklog)) + o; +} + +/* + * Convert block (DB) to block (dablk) + */ +static inline xfs_dablk_t +xfs_dir2_db_to_da(struct xfs_mount *mp, xfs_dir2_db_t db) +{ + return (xfs_dablk_t)(db << mp->m_sb.sb_dirblklog); +} + +/* + * Convert byte in space to (DA) block + */ +static inline xfs_dablk_t +xfs_dir2_byte_to_da(struct xfs_mount *mp, xfs_dir2_off_t by) +{ + return xfs_dir2_db_to_da(mp, xfs_dir2_byte_to_db(mp, by)); +} + +/* + * Convert block and offset to dataptr + */ +static inline xfs_dir2_dataptr_t +xfs_dir2_db_off_to_dataptr(struct xfs_mount *mp, xfs_dir2_db_t db, + xfs_dir2_data_aoff_t o) +{ + return xfs_dir2_byte_to_dataptr(mp, xfs_dir2_db_off_to_byte(mp, db, o)); +} + +/* + * Convert block (dablk) to block (DB) + */ +static inline xfs_dir2_db_t +xfs_dir2_da_to_db(struct xfs_mount *mp, xfs_dablk_t da) +{ + return (xfs_dir2_db_t)(da >> mp->m_sb.sb_dirblklog); +} + +/* + * Convert block (dablk) to byte offset in space + */ +static inline xfs_dir2_off_t +xfs_dir2_da_to_byte(struct xfs_mount *mp, xfs_dablk_t da) +{ + return xfs_dir2_db_off_to_byte(mp, xfs_dir2_da_to_db(mp, da), 0); +} + +/* + * Free space block defintions for the node format. + */ + +/* + * Offset of the freespace index. + */ +#define XFS_DIR2_FREE_SPACE 2 +#define XFS_DIR2_FREE_OFFSET (XFS_DIR2_FREE_SPACE * XFS_DIR2_SPACE_SIZE) +#define XFS_DIR2_FREE_FIRSTDB(mp) \ + xfs_dir2_byte_to_db(mp, XFS_DIR2_FREE_OFFSET) + +typedef struct xfs_dir2_free_hdr { + __be32 magic; /* XFS_DIR2_FREE_MAGIC */ + __be32 firstdb; /* db of first entry */ + __be32 nvalid; /* count of valid entries */ + __be32 nused; /* count of used entries */ +} xfs_dir2_free_hdr_t; + +typedef struct xfs_dir2_free { + xfs_dir2_free_hdr_t hdr; /* block header */ + __be16 bests[]; /* best free counts */ + /* unused entries are -1 */ +} xfs_dir2_free_t; + +static inline int xfs_dir2_free_max_bests(struct xfs_mount *mp) +{ + return (mp->m_dirblksize - sizeof(struct xfs_dir2_free_hdr)) / + sizeof(xfs_dir2_data_off_t); +} + +/* + * Convert data space db to the corresponding free db. + */ +static inline xfs_dir2_db_t +xfs_dir2_db_to_fdb(struct xfs_mount *mp, xfs_dir2_db_t db) +{ + return XFS_DIR2_FREE_FIRSTDB(mp) + db / xfs_dir2_free_max_bests(mp); +} + +/* + * Convert data space db to the corresponding index in a free db. + */ +static inline int +xfs_dir2_db_to_fdindex(struct xfs_mount *mp, xfs_dir2_db_t db) +{ + return db % xfs_dir2_free_max_bests(mp); +} + +/* + * Single block format. + * + * The single block format looks like the following drawing on disk: + * + * +-------------------------------------------------+ + * | xfs_dir2_data_hdr_t | + * +-------------------------------------------------+ + * | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t | + * | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t | + * | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t : + * | ... | + * +-------------------------------------------------+ + * | unused space | + * +-------------------------------------------------+ + * | ... | + * | xfs_dir2_leaf_entry_t | + * | xfs_dir2_leaf_entry_t | + * +-------------------------------------------------+ + * | xfs_dir2_block_tail_t | + * +-------------------------------------------------+ + * + * As all the entries are variable size structures the accessors below should + * be used to iterate over them. + */ + +typedef struct xfs_dir2_block_tail { + __be32 count; /* count of leaf entries */ + __be32 stale; /* count of stale lf entries */ +} xfs_dir2_block_tail_t; + +/* + * Pointer to the leaf header embedded in a data block (1-block format) + */ +static inline struct xfs_dir2_block_tail * +xfs_dir2_block_tail_p(struct xfs_mount *mp, struct xfs_dir2_data_hdr *hdr) +{ + return ((struct xfs_dir2_block_tail *) + ((char *)hdr + mp->m_dirblksize)) - 1; +} + +/* + * Pointer to the leaf entries embedded in a data block (1-block format) + */ +static inline struct xfs_dir2_leaf_entry * +xfs_dir2_block_leaf_p(struct xfs_dir2_block_tail *btp) +{ + return ((struct xfs_dir2_leaf_entry *)btp) - be32_to_cpu(btp->count); +} + +#endif /* __XFS_DIR2_FORMAT_H__ */ |