diff options
| -rw-r--r-- | fs/xfs/libxfs/xfs_btree.c | 264 | ||||
| -rw-r--r-- | fs/xfs/libxfs/xfs_btree.h | 22 | ||||
| -rw-r--r-- | fs/xfs/xfs_trace.h | 1 |
3 files changed, 282 insertions, 5 deletions
diff --git a/fs/xfs/libxfs/xfs_btree.c b/fs/xfs/libxfs/xfs_btree.c index 5c1b35a23a3d..d79dcb08ed18 100644 --- a/fs/xfs/libxfs/xfs_btree.c +++ b/fs/xfs/libxfs/xfs_btree.c @@ -4521,3 +4521,267 @@ xfs_btree_compute_maxlevels( maxblocks = (maxblocks + limits[1] - 1) / limits[1]; return level; } + +/* + * Query a regular btree for all records overlapping a given interval. + * Start with a LE lookup of the key of low_rec and return all records + * until we find a record with a key greater than the key of high_rec. + */ +STATIC int +xfs_btree_simple_query_range( + struct xfs_btree_cur *cur, + union xfs_btree_key *low_key, + union xfs_btree_key *high_key, + xfs_btree_query_range_fn fn, + void *priv) +{ + union xfs_btree_rec *recp; + union xfs_btree_key rec_key; + __int64_t diff; + int stat; + bool firstrec = true; + int error; + + ASSERT(cur->bc_ops->init_high_key_from_rec); + ASSERT(cur->bc_ops->diff_two_keys); + + /* + * Find the leftmost record. The btree cursor must be set + * to the low record used to generate low_key. + */ + stat = 0; + error = xfs_btree_lookup(cur, XFS_LOOKUP_LE, &stat); + if (error) + goto out; + + while (stat) { + /* Find the record. */ + error = xfs_btree_get_rec(cur, &recp, &stat); + if (error || !stat) + break; + cur->bc_ops->init_high_key_from_rec(&rec_key, recp); + + /* Skip if high_key(rec) < low_key. */ + if (firstrec) { + firstrec = false; + diff = cur->bc_ops->diff_two_keys(cur, low_key, + &rec_key); + if (diff > 0) + goto advloop; + } + + /* Stop if high_key < low_key(rec). */ + diff = cur->bc_ops->diff_two_keys(cur, &rec_key, high_key); + if (diff > 0) + break; + + /* Callback */ + error = fn(cur, recp, priv); + if (error < 0 || error == XFS_BTREE_QUERY_RANGE_ABORT) + break; + +advloop: + /* Move on to the next record. */ + error = xfs_btree_increment(cur, 0, &stat); + if (error) + break; + } + +out: + return error; +} + +/* + * Query an overlapped interval btree for all records overlapping a given + * interval. This function roughly follows the algorithm given in + * "Interval Trees" of _Introduction to Algorithms_, which is section + * 14.3 in the 2nd and 3rd editions. + * + * First, generate keys for the low and high records passed in. + * + * For any leaf node, generate the high and low keys for the record. + * If the record keys overlap with the query low/high keys, pass the + * record to the function iterator. + * + * For any internal node, compare the low and high keys of each + * pointer against the query low/high keys. If there's an overlap, + * follow the pointer. + * + * As an optimization, we stop scanning a block when we find a low key + * that is greater than the query's high key. + */ +STATIC int +xfs_btree_overlapped_query_range( + struct xfs_btree_cur *cur, + union xfs_btree_key *low_key, + union xfs_btree_key *high_key, + xfs_btree_query_range_fn fn, + void *priv) +{ + union xfs_btree_ptr ptr; + union xfs_btree_ptr *pp; + union xfs_btree_key rec_key; + union xfs_btree_key rec_hkey; + union xfs_btree_key *lkp; + union xfs_btree_key *hkp; + union xfs_btree_rec *recp; + struct xfs_btree_block *block; + __int64_t ldiff; + __int64_t hdiff; + int level; + struct xfs_buf *bp; + int i; + int error; + + /* Load the root of the btree. */ + level = cur->bc_nlevels - 1; + cur->bc_ops->init_ptr_from_cur(cur, &ptr); + error = xfs_btree_lookup_get_block(cur, level, &ptr, &block); + if (error) + return error; + xfs_btree_get_block(cur, level, &bp); + trace_xfs_btree_overlapped_query_range(cur, level, bp); +#ifdef DEBUG + error = xfs_btree_check_block(cur, block, level, bp); + if (error) + goto out; +#endif + cur->bc_ptrs[level] = 1; + + while (level < cur->bc_nlevels) { + block = xfs_btree_get_block(cur, level, &bp); + + /* End of node, pop back towards the root. */ + if (cur->bc_ptrs[level] > be16_to_cpu(block->bb_numrecs)) { +pop_up: + if (level < cur->bc_nlevels - 1) + cur->bc_ptrs[level + 1]++; + level++; + continue; + } + + if (level == 0) { + /* Handle a leaf node. */ + recp = xfs_btree_rec_addr(cur, cur->bc_ptrs[0], block); + + cur->bc_ops->init_high_key_from_rec(&rec_hkey, recp); + ldiff = cur->bc_ops->diff_two_keys(cur, &rec_hkey, + low_key); + + cur->bc_ops->init_key_from_rec(&rec_key, recp); + hdiff = cur->bc_ops->diff_two_keys(cur, high_key, + &rec_key); + + /* + * If (record's high key >= query's low key) and + * (query's high key >= record's low key), then + * this record overlaps the query range; callback. + */ + if (ldiff >= 0 && hdiff >= 0) { + error = fn(cur, recp, priv); + if (error < 0 || + error == XFS_BTREE_QUERY_RANGE_ABORT) + break; + } else if (hdiff < 0) { + /* Record is larger than high key; pop. */ + goto pop_up; + } + cur->bc_ptrs[level]++; + continue; + } + + /* Handle an internal node. */ + lkp = xfs_btree_key_addr(cur, cur->bc_ptrs[level], block); + hkp = xfs_btree_high_key_addr(cur, cur->bc_ptrs[level], block); + pp = xfs_btree_ptr_addr(cur, cur->bc_ptrs[level], block); + + ldiff = cur->bc_ops->diff_two_keys(cur, hkp, low_key); + hdiff = cur->bc_ops->diff_two_keys(cur, high_key, lkp); + + /* + * If (pointer's high key >= query's low key) and + * (query's high key >= pointer's low key), then + * this record overlaps the query range; follow pointer. + */ + if (ldiff >= 0 && hdiff >= 0) { + level--; + error = xfs_btree_lookup_get_block(cur, level, pp, + &block); + if (error) + goto out; + xfs_btree_get_block(cur, level, &bp); + trace_xfs_btree_overlapped_query_range(cur, level, bp); +#ifdef DEBUG + error = xfs_btree_check_block(cur, block, level, bp); + if (error) + goto out; +#endif + cur->bc_ptrs[level] = 1; + continue; + } else if (hdiff < 0) { + /* The low key is larger than the upper range; pop. */ + goto pop_up; + } + cur->bc_ptrs[level]++; + } + +out: + /* + * If we don't end this function with the cursor pointing at a record + * block, a subsequent non-error cursor deletion will not release + * node-level buffers, causing a buffer leak. This is quite possible + * with a zero-results range query, so release the buffers if we + * failed to return any results. + */ + if (cur->bc_bufs[0] == NULL) { + for (i = 0; i < cur->bc_nlevels; i++) { + if (cur->bc_bufs[i]) { + xfs_trans_brelse(cur->bc_tp, cur->bc_bufs[i]); + cur->bc_bufs[i] = NULL; + cur->bc_ptrs[i] = 0; + cur->bc_ra[i] = 0; + } + } + } + + return error; +} + +/* + * Query a btree for all records overlapping a given interval of keys. The + * supplied function will be called with each record found; return one of the + * XFS_BTREE_QUERY_RANGE_{CONTINUE,ABORT} values or the usual negative error + * code. This function returns XFS_BTREE_QUERY_RANGE_ABORT, zero, or a + * negative error code. + */ +int +xfs_btree_query_range( + struct xfs_btree_cur *cur, + union xfs_btree_irec *low_rec, + union xfs_btree_irec *high_rec, + xfs_btree_query_range_fn fn, + void *priv) +{ + union xfs_btree_rec rec; + union xfs_btree_key low_key; + union xfs_btree_key high_key; + + /* Find the keys of both ends of the interval. */ + cur->bc_rec = *high_rec; + cur->bc_ops->init_rec_from_cur(cur, &rec); + cur->bc_ops->init_key_from_rec(&high_key, &rec); + + cur->bc_rec = *low_rec; + cur->bc_ops->init_rec_from_cur(cur, &rec); + cur->bc_ops->init_key_from_rec(&low_key, &rec); + + /* Enforce low key < high key. */ + if (cur->bc_ops->diff_two_keys(cur, &low_key, &high_key) > 0) + return -EINVAL; + + if (!(cur->bc_flags & XFS_BTREE_OVERLAPPING)) + return xfs_btree_simple_query_range(cur, &low_key, + &high_key, fn, priv); + return xfs_btree_overlapped_query_range(cur, &low_key, &high_key, + fn, priv); +} diff --git a/fs/xfs/libxfs/xfs_btree.h b/fs/xfs/libxfs/xfs_btree.h index bce6daacb1f7..34c13616d255 100644 --- a/fs/xfs/libxfs/xfs_btree.h +++ b/fs/xfs/libxfs/xfs_btree.h @@ -227,6 +227,12 @@ struct xfs_btree_ops { #define LASTREC_DELREC 2 +union xfs_btree_irec { + struct xfs_alloc_rec_incore a; + struct xfs_bmbt_irec b; + struct xfs_inobt_rec_incore i; +}; + /* * Btree cursor structure. * This collects all information needed by the btree code in one place. @@ -237,11 +243,7 @@ typedef struct xfs_btree_cur struct xfs_mount *bc_mp; /* file system mount struct */ const struct xfs_btree_ops *bc_ops; uint bc_flags; /* btree features - below */ - union { - xfs_alloc_rec_incore_t a; - xfs_bmbt_irec_t b; - xfs_inobt_rec_incore_t i; - } bc_rec; /* current insert/search record value */ + union xfs_btree_irec bc_rec; /* current insert/search record value */ struct xfs_buf *bc_bufs[XFS_BTREE_MAXLEVELS]; /* buf ptr per level */ int bc_ptrs[XFS_BTREE_MAXLEVELS]; /* key/record # */ __uint8_t bc_ra[XFS_BTREE_MAXLEVELS]; /* readahead bits */ @@ -524,4 +526,14 @@ void xfs_btree_get_node_keys_overlapped(struct xfs_btree_cur *cur, struct xfs_btree_block *block, union xfs_btree_key *key); int xfs_btree_update_keys_overlapped(struct xfs_btree_cur *cur, int level); +/* return codes */ +#define XFS_BTREE_QUERY_RANGE_CONTINUE 0 /* keep iterating */ +#define XFS_BTREE_QUERY_RANGE_ABORT 1 /* stop iterating */ +typedef int (*xfs_btree_query_range_fn)(struct xfs_btree_cur *cur, + union xfs_btree_rec *rec, void *priv); + +int xfs_btree_query_range(struct xfs_btree_cur *cur, + union xfs_btree_irec *low_rec, union xfs_btree_irec *high_rec, + xfs_btree_query_range_fn fn, void *priv); + #endif /* __XFS_BTREE_H__ */ diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h index 8fb59e644f80..a5862680db31 100644 --- a/fs/xfs/xfs_trace.h +++ b/fs/xfs/xfs_trace.h @@ -2220,6 +2220,7 @@ DEFINE_EVENT(xfs_btree_cur_class, name, \ TP_PROTO(struct xfs_btree_cur *cur, int level, struct xfs_buf *bp), \ TP_ARGS(cur, level, bp)) DEFINE_BTREE_CUR_EVENT(xfs_btree_updkeys); +DEFINE_BTREE_CUR_EVENT(xfs_btree_overlapped_query_range); #endif /* _TRACE_XFS_H */ |