diff options
| -rw-r--r-- | fs/xfs/xfs_alloc_btree.c | 3 | ||||
| -rw-r--r-- | fs/xfs/xfs_bmap_btree.c | 3 | ||||
| -rw-r--r-- | fs/xfs/xfs_btree.c | 130 | ||||
| -rw-r--r-- | fs/xfs/xfs_btree.h | 13 | ||||
| -rw-r--r-- | fs/xfs/xfs_ialloc_btree.c | 3 |
5 files changed, 152 insertions, 0 deletions
diff --git a/fs/xfs/xfs_alloc_btree.c b/fs/xfs/xfs_alloc_btree.c index 1f268b6f4362..9e2421c31a36 100644 --- a/fs/xfs/xfs_alloc_btree.c +++ b/fs/xfs/xfs_alloc_btree.c @@ -2294,6 +2294,9 @@ xfs_allocbt_trace_record( #endif /* XFS_BTREE_TRACE */ static const struct xfs_btree_ops xfs_allocbt_ops = { + .rec_len = sizeof(xfs_alloc_rec_t), + .key_len = sizeof(xfs_alloc_key_t), + .dup_cursor = xfs_allocbt_dup_cursor, .get_maxrecs = xfs_allocbt_get_maxrecs, diff --git a/fs/xfs/xfs_bmap_btree.c b/fs/xfs/xfs_bmap_btree.c index bdcfbea1e062..a71010abf6ec 100644 --- a/fs/xfs/xfs_bmap_btree.c +++ b/fs/xfs/xfs_bmap_btree.c @@ -2509,6 +2509,9 @@ xfs_bmbt_trace_record( #endif /* XFS_BTREE_TRACE */ static const struct xfs_btree_ops xfs_bmbt_ops = { + .rec_len = sizeof(xfs_bmbt_rec_t), + .key_len = sizeof(xfs_bmbt_key_t), + .dup_cursor = xfs_bmbt_dup_cursor, .get_maxrecs = xfs_bmbt_get_maxrecs, diff --git a/fs/xfs/xfs_btree.c b/fs/xfs/xfs_btree.c index 893e86f2ad57..4aec7c7d5ba9 100644 --- a/fs/xfs/xfs_btree.c +++ b/fs/xfs/xfs_btree.c @@ -403,6 +403,136 @@ xfs_btree_dup_cursor( } /* + * XFS btree block layout and addressing: + * + * There are two types of blocks in the btree: leaf and non-leaf blocks. + * + * The leaf record start with a header then followed by records containing + * the values. A non-leaf block also starts with the same header, and + * then first contains lookup keys followed by an equal number of pointers + * to the btree blocks at the previous level. + * + * +--------+-------+-------+-------+-------+-------+-------+ + * Leaf: | header | rec 1 | rec 2 | rec 3 | rec 4 | rec 5 | rec N | + * +--------+-------+-------+-------+-------+-------+-------+ + * + * +--------+-------+-------+-------+-------+-------+-------+ + * Non-Leaf: | header | key 1 | key 2 | key N | ptr 1 | ptr 2 | ptr N | + * +--------+-------+-------+-------+-------+-------+-------+ + * + * The header is called struct xfs_btree_block for reasons better left unknown + * and comes in different versions for short (32bit) and long (64bit) block + * pointers. The record and key structures are defined by the btree instances + * and opaque to the btree core. The block pointers are simple disk endian + * integers, available in a short (32bit) and long (64bit) variant. + * + * The helpers below calculate the offset of a given record, key or pointer + * into a btree block (xfs_btree_*_offset) or return a pointer to the given + * record, key or pointer (xfs_btree_*_addr). Note that all addressing + * inside the btree block is done using indices starting at one, not zero! + */ + +/* + * Return size of the btree block header for this btree instance. + */ +static inline size_t xfs_btree_block_len(struct xfs_btree_cur *cur) +{ + return (cur->bc_flags & XFS_BTREE_LONG_PTRS) ? + sizeof(struct xfs_btree_lblock) : + sizeof(struct xfs_btree_sblock); +} + +/* + * Return size of btree block pointers for this btree instance. + */ +static inline size_t xfs_btree_ptr_len(struct xfs_btree_cur *cur) +{ + return (cur->bc_flags & XFS_BTREE_LONG_PTRS) ? + sizeof(__be64) : sizeof(__be32); +} + +/* + * Calculate offset of the n-th record in a btree block. + */ +STATIC size_t +xfs_btree_rec_offset( + struct xfs_btree_cur *cur, + int n) +{ + return xfs_btree_block_len(cur) + + (n - 1) * cur->bc_ops->rec_len; +} + +/* + * Calculate offset of the n-th key in a btree block. + */ +STATIC size_t +xfs_btree_key_offset( + struct xfs_btree_cur *cur, + int n) +{ + return xfs_btree_block_len(cur) + + (n - 1) * cur->bc_ops->key_len; +} + +/* + * Calculate offset of the n-th block pointer in a btree block. + */ +STATIC size_t +xfs_btree_ptr_offset( + struct xfs_btree_cur *cur, + int n, + int level) +{ + return xfs_btree_block_len(cur) + + cur->bc_ops->get_maxrecs(cur, level) * cur->bc_ops->key_len + + (n - 1) * xfs_btree_ptr_len(cur); +} + +/* + * Return a pointer to the n-th record in the btree block. + */ +STATIC union xfs_btree_rec * +xfs_btree_rec_addr( + struct xfs_btree_cur *cur, + int n, + struct xfs_btree_block *block) +{ + return (union xfs_btree_rec *) + ((char *)block + xfs_btree_rec_offset(cur, n)); +} + +/* + * Return a pointer to the n-th key in the btree block. + */ +STATIC union xfs_btree_key * +xfs_btree_key_addr( + struct xfs_btree_cur *cur, + int n, + struct xfs_btree_block *block) +{ + return (union xfs_btree_key *) + ((char *)block + xfs_btree_key_offset(cur, n)); +} + +/* + * Return a pointer to the n-th block pointer in the btree block. + */ +STATIC union xfs_btree_ptr * +xfs_btree_ptr_addr( + struct xfs_btree_cur *cur, + int n, + struct xfs_btree_block *block) +{ + int level = xfs_btree_get_level(block); + + ASSERT(block->bb_level != 0); + + return (union xfs_btree_ptr *) + ((char *)block + xfs_btree_ptr_offset(cur, n, level)); +} + +/* * Get a the root block which is stored in the inode. * * For now this btree implementation assumes the btree root is always diff --git a/fs/xfs/xfs_btree.h b/fs/xfs/xfs_btree.h index 5398cd0d4d4d..593f82b01b6f 100644 --- a/fs/xfs/xfs_btree.h +++ b/fs/xfs/xfs_btree.h @@ -180,6 +180,10 @@ do { \ #define XFS_BTREE_MAXLEVELS 8 /* max of all btrees */ struct xfs_btree_ops { + /* size of the key and record structures */ + size_t key_len; + size_t rec_len; + /* cursor operations */ struct xfs_btree_cur *(*dup_cursor)(struct xfs_btree_cur *); @@ -497,6 +501,15 @@ xfs_btree_setbuf( int lev, /* level in btree */ struct xfs_buf *bp); /* new buffer to set */ + +/* + * Helpers. + */ +static inline int xfs_btree_get_level(struct xfs_btree_block *block) +{ + return be16_to_cpu(block->bb_level); +} + #endif /* __KERNEL__ */ diff --git a/fs/xfs/xfs_ialloc_btree.c b/fs/xfs/xfs_ialloc_btree.c index 18867f1aacac..fc6db94492dc 100644 --- a/fs/xfs/xfs_ialloc_btree.c +++ b/fs/xfs/xfs_ialloc_btree.c @@ -2160,6 +2160,9 @@ xfs_inobt_trace_record( #endif /* XFS_BTREE_TRACE */ static const struct xfs_btree_ops xfs_inobt_ops = { + .rec_len = sizeof(xfs_inobt_rec_t), + .key_len = sizeof(xfs_inobt_key_t), + .dup_cursor = xfs_inobt_dup_cursor, .get_maxrecs = xfs_inobt_get_maxrecs, |
