From fe033cc848489851f0c7de48f0b1bab5d744ad8a Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Thu, 30 Oct 2008 16:56:09 +1100 Subject: [XFS] implement generic xfs_btree_lookup From: Dave Chinner [hch: split out from bigger patch and minor adaptions] SGI-PV: 985583 SGI-Modid: xfs-linux-melb:xfs-kern:32192a Signed-off-by: Christoph Hellwig Signed-off-by: Lachlan McIlroy Signed-off-by: Bill O'Donnell Signed-off-by: David Chinner --- fs/xfs/xfs_alloc_btree.c | 312 ++++++++--------------------------------------- 1 file changed, 48 insertions(+), 264 deletions(-) (limited to 'fs/xfs/xfs_alloc_btree.c') diff --git a/fs/xfs/xfs_alloc_btree.c b/fs/xfs/xfs_alloc_btree.c index 6b45481ad5b0..b81fbf1216ed 100644 --- a/fs/xfs/xfs_alloc_btree.c +++ b/fs/xfs/xfs_alloc_btree.c @@ -937,223 +937,6 @@ xfs_alloc_log_recs( xfs_trans_log_buf(cur->bc_tp, bp, first, last); } -/* - * Lookup the record. The cursor is made to point to it, based on dir. - * Return 0 if can't find any such record, 1 for success. - */ -STATIC int /* error */ -xfs_alloc_lookup( - xfs_btree_cur_t *cur, /* btree cursor */ - xfs_lookup_t dir, /* <=, ==, or >= */ - int *stat) /* success/failure */ -{ - xfs_agblock_t agbno; /* a.g. relative btree block number */ - xfs_agnumber_t agno; /* allocation group number */ - xfs_alloc_block_t *block=NULL; /* current btree block */ - int diff; /* difference for the current key */ - int error; /* error return value */ - int keyno=0; /* current key number */ - int level; /* level in the btree */ - xfs_mount_t *mp; /* file system mount point */ - - XFS_STATS_INC(xs_abt_lookup); - /* - * Get the allocation group header, and the root block number. - */ - mp = cur->bc_mp; - - { - xfs_agf_t *agf; /* a.g. freespace header */ - - agf = XFS_BUF_TO_AGF(cur->bc_private.a.agbp); - agno = be32_to_cpu(agf->agf_seqno); - agbno = be32_to_cpu(agf->agf_roots[cur->bc_btnum]); - } - /* - * Iterate over each level in the btree, starting at the root. - * For each level above the leaves, find the key we need, based - * on the lookup record, then follow the corresponding block - * pointer down to the next level. - */ - for (level = cur->bc_nlevels - 1, diff = 1; level >= 0; level--) { - xfs_buf_t *bp; /* buffer pointer for btree block */ - xfs_daddr_t d; /* disk address of btree block */ - - /* - * Get the disk address we're looking for. - */ - d = XFS_AGB_TO_DADDR(mp, agno, agbno); - /* - * If the old buffer at this level is for a different block, - * throw it away, otherwise just use it. - */ - bp = cur->bc_bufs[level]; - if (bp && XFS_BUF_ADDR(bp) != d) - bp = NULL; - if (!bp) { - /* - * Need to get a new buffer. Read it, then - * set it in the cursor, releasing the old one. - */ - if ((error = xfs_btree_read_bufs(mp, cur->bc_tp, agno, - agbno, 0, &bp, XFS_ALLOC_BTREE_REF))) - return error; - xfs_btree_setbuf(cur, level, bp); - /* - * Point to the btree block, now that we have the buffer - */ - block = XFS_BUF_TO_ALLOC_BLOCK(bp); - if ((error = xfs_btree_check_sblock(cur, block, level, - bp))) - return error; - } else - block = XFS_BUF_TO_ALLOC_BLOCK(bp); - /* - * If we already had a key match at a higher level, we know - * we need to use the first entry in this block. - */ - if (diff == 0) - keyno = 1; - /* - * Otherwise we need to search this block. Do a binary search. - */ - else { - int high; /* high entry number */ - xfs_alloc_key_t *kkbase=NULL;/* base of keys in block */ - xfs_alloc_rec_t *krbase=NULL;/* base of records in block */ - int low; /* low entry number */ - - /* - * Get a pointer to keys or records. - */ - if (level > 0) - kkbase = XFS_ALLOC_KEY_ADDR(block, 1, cur); - else - krbase = XFS_ALLOC_REC_ADDR(block, 1, cur); - /* - * Set low and high entry numbers, 1-based. - */ - low = 1; - if (!(high = be16_to_cpu(block->bb_numrecs))) { - /* - * If the block is empty, the tree must - * be an empty leaf. - */ - ASSERT(level == 0 && cur->bc_nlevels == 1); - cur->bc_ptrs[0] = dir != XFS_LOOKUP_LE; - *stat = 0; - return 0; - } - /* - * Binary search the block. - */ - while (low <= high) { - xfs_extlen_t blockcount; /* key value */ - xfs_agblock_t startblock; /* key value */ - - XFS_STATS_INC(xs_abt_compare); - /* - * keyno is average of low and high. - */ - keyno = (low + high) >> 1; - /* - * Get startblock & blockcount. - */ - if (level > 0) { - xfs_alloc_key_t *kkp; - - kkp = kkbase + keyno - 1; - startblock = be32_to_cpu(kkp->ar_startblock); - blockcount = be32_to_cpu(kkp->ar_blockcount); - } else { - xfs_alloc_rec_t *krp; - - krp = krbase + keyno - 1; - startblock = be32_to_cpu(krp->ar_startblock); - blockcount = be32_to_cpu(krp->ar_blockcount); - } - /* - * Compute difference to get next direction. - */ - if (cur->bc_btnum == XFS_BTNUM_BNO) - diff = (int)startblock - - (int)cur->bc_rec.a.ar_startblock; - else if (!(diff = (int)blockcount - - (int)cur->bc_rec.a.ar_blockcount)) - diff = (int)startblock - - (int)cur->bc_rec.a.ar_startblock; - /* - * Less than, move right. - */ - if (diff < 0) - low = keyno + 1; - /* - * Greater than, move left. - */ - else if (diff > 0) - high = keyno - 1; - /* - * Equal, we're done. - */ - else - break; - } - } - /* - * If there are more levels, set up for the next level - * by getting the block number and filling in the cursor. - */ - if (level > 0) { - /* - * If we moved left, need the previous key number, - * unless there isn't one. - */ - if (diff > 0 && --keyno < 1) - keyno = 1; - agbno = be32_to_cpu(*XFS_ALLOC_PTR_ADDR(block, keyno, cur)); -#ifdef DEBUG - if ((error = xfs_btree_check_sptr(cur, agbno, level))) - return error; -#endif - cur->bc_ptrs[level] = keyno; - } - } - /* - * Done with the search. - * See if we need to adjust the results. - */ - if (dir != XFS_LOOKUP_LE && diff < 0) { - keyno++; - /* - * If ge search and we went off the end of the block, but it's - * not the last block, we're in the wrong block. - */ - if (dir == XFS_LOOKUP_GE && - keyno > be16_to_cpu(block->bb_numrecs) && - be32_to_cpu(block->bb_rightsib) != NULLAGBLOCK) { - int i; - - cur->bc_ptrs[0] = keyno; - if ((error = xfs_btree_increment(cur, 0, &i))) - return error; - XFS_WANT_CORRUPTED_RETURN(i == 1); - *stat = 1; - return 0; - } - } - else if (dir == XFS_LOOKUP_LE && diff > 0) - keyno--; - cur->bc_ptrs[0] = keyno; - /* - * Return if we succeeded or not. - */ - if (keyno == 0 || keyno > be16_to_cpu(block->bb_numrecs)) - *stat = 0; - else - *stat = ((dir != XFS_LOOKUP_EQ) || (diff == 0)); - return 0; -} - /* * Move 1 record left from cur/level if possible. * Update cur to reflect the new path. @@ -1918,53 +1701,6 @@ xfs_alloc_insert( return 0; } -/* - * Lookup the record equal to [bno, len] in the btree given by cur. - */ -int /* error */ -xfs_alloc_lookup_eq( - xfs_btree_cur_t *cur, /* btree cursor */ - xfs_agblock_t bno, /* starting block of extent */ - xfs_extlen_t len, /* length of extent */ - int *stat) /* success/failure */ -{ - cur->bc_rec.a.ar_startblock = bno; - cur->bc_rec.a.ar_blockcount = len; - return xfs_alloc_lookup(cur, XFS_LOOKUP_EQ, stat); -} - -/* - * Lookup the first record greater than or equal to [bno, len] - * in the btree given by cur. - */ -int /* error */ -xfs_alloc_lookup_ge( - xfs_btree_cur_t *cur, /* btree cursor */ - xfs_agblock_t bno, /* starting block of extent */ - xfs_extlen_t len, /* length of extent */ - int *stat) /* success/failure */ -{ - cur->bc_rec.a.ar_startblock = bno; - cur->bc_rec.a.ar_blockcount = len; - return xfs_alloc_lookup(cur, XFS_LOOKUP_GE, stat); -} - -/* - * Lookup the first record less than or equal to [bno, len] - * in the btree given by cur. - */ -int /* error */ -xfs_alloc_lookup_le( - xfs_btree_cur_t *cur, /* btree cursor */ - xfs_agblock_t bno, /* starting block of extent */ - xfs_extlen_t len, /* length of extent */ - int *stat) /* success/failure */ -{ - cur->bc_rec.a.ar_startblock = bno; - cur->bc_rec.a.ar_blockcount = len; - return xfs_alloc_lookup(cur, XFS_LOOKUP_LE, stat); -} - /* * Update the record referred to by cur, to the value given by [bno, len]. * This either works (return 0) or gets an EFSCORRUPTED error. @@ -2052,6 +1788,51 @@ xfs_allocbt_get_maxrecs( return cur->bc_mp->m_alloc_mxr[level != 0]; } +STATIC void +xfs_allocbt_init_key_from_rec( + union xfs_btree_key *key, + union xfs_btree_rec *rec) +{ + ASSERT(rec->alloc.ar_startblock != 0); + + key->alloc.ar_startblock = rec->alloc.ar_startblock; + key->alloc.ar_blockcount = rec->alloc.ar_blockcount; +} + +STATIC void +xfs_allocbt_init_ptr_from_cur( + struct xfs_btree_cur *cur, + union xfs_btree_ptr *ptr) +{ + struct xfs_agf *agf = XFS_BUF_TO_AGF(cur->bc_private.a.agbp); + + ASSERT(cur->bc_private.a.agno == be32_to_cpu(agf->agf_seqno)); + ASSERT(agf->agf_roots[cur->bc_btnum] != 0); + + ptr->s = agf->agf_roots[cur->bc_btnum]; +} + +STATIC __int64_t +xfs_allocbt_key_diff( + struct xfs_btree_cur *cur, + union xfs_btree_key *key) +{ + xfs_alloc_rec_incore_t *rec = &cur->bc_rec.a; + xfs_alloc_key_t *kp = &key->alloc; + __int64_t diff; + + if (cur->bc_btnum == XFS_BTNUM_BNO) { + return (__int64_t)be32_to_cpu(kp->ar_startblock) - + rec->ar_startblock; + } + + diff = (__int64_t)be32_to_cpu(kp->ar_blockcount) - rec->ar_blockcount; + if (diff) + return diff; + + return (__int64_t)be32_to_cpu(kp->ar_startblock) - rec->ar_startblock; +} + #ifdef XFS_BTREE_TRACE ktrace_t *xfs_allocbt_trace_buf; @@ -2124,6 +1905,9 @@ static const struct xfs_btree_ops xfs_allocbt_ops = { .dup_cursor = xfs_allocbt_dup_cursor, .get_maxrecs = xfs_allocbt_get_maxrecs, + .init_key_from_rec = xfs_allocbt_init_key_from_rec, + .init_ptr_from_cur = xfs_allocbt_init_ptr_from_cur, + .key_diff = xfs_allocbt_key_diff, #ifdef XFS_BTREE_TRACE .trace_enter = xfs_allocbt_trace_enter, -- cgit v1.2.3-59-g8ed1b