[XFS] add helpers for addressing entities inside a btree block (65f1eaea) · Commits · 戴 / test

fs/xfs/xfs_alloc_btree.c

+3 −0

Original line number	Diff line number	Diff line
		@@ -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,

fs/xfs/xfs_bmap_btree.c

+3 −0

Original line number	Diff line number	Diff line
		@@ -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,

fs/xfs/xfs_btree.c

+130 −0

Original line number	Diff line number	Diff line
		@@ -402,6 +402,136 @@ xfs_btree_dup_cursor(
		return 0;
		}

		/*
		* 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.
		*

fs/xfs/xfs_btree.h

+13 −0

Original line number	Diff line number	Diff line
		@@ -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__ */

fs/xfs/xfs_ialloc_btree.c

+3 −0

Original line number	Diff line number	Diff line
		@@ -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,

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