dm table: validate device logical_block_size
Impose necessary and sufficient conditions on a devices's table such that any incoming bio which respects its logical_block_size can be processed successfully. Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
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@ -724,6 +724,71 @@ static void check_for_valid_limits(struct io_restrictions *rs)
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rs->bounce_pfn = -1;
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rs->bounce_pfn = -1;
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}
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}
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/*
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* Impose necessary and sufficient conditions on a devices's table such
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* that any incoming bio which respects its logical_block_size can be
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* processed successfully. If it falls across the boundary between
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* two or more targets, the size of each piece it gets split into must
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* be compatible with the logical_block_size of the target processing it.
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*/
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static int validate_hardware_logical_block_alignment(struct dm_table *table)
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{
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/*
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* This function uses arithmetic modulo the logical_block_size
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* (in units of 512-byte sectors).
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*/
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unsigned short device_logical_block_size_sects =
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table->limits.logical_block_size >> SECTOR_SHIFT;
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/*
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* Offset of the start of the next table entry, mod logical_block_size.
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*/
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unsigned short next_target_start = 0;
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/*
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* Given an aligned bio that extends beyond the end of a
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* target, how many sectors must the next target handle?
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*/
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unsigned short remaining = 0;
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struct dm_target *uninitialized_var(ti);
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unsigned i = 0;
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/*
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* Check each entry in the table in turn.
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*/
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while (i < dm_table_get_num_targets(table)) {
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ti = dm_table_get_target(table, i++);
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/*
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* If the remaining sectors fall entirely within this
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* table entry are they compatible with its logical_block_size?
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*/
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if (remaining < ti->len &&
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remaining & ((ti->limits.logical_block_size >>
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SECTOR_SHIFT) - 1))
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break; /* Error */
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next_target_start =
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(unsigned short) ((next_target_start + ti->len) &
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(device_logical_block_size_sects - 1));
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remaining = next_target_start ?
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device_logical_block_size_sects - next_target_start : 0;
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}
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if (remaining) {
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DMWARN("%s: table line %u (start sect %llu len %llu) "
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"not aligned to hardware logical block size %hu",
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dm_device_name(table->md), i,
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(unsigned long long) ti->begin,
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(unsigned long long) ti->len,
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table->limits.logical_block_size);
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return -EINVAL;
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}
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return 0;
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}
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int dm_table_add_target(struct dm_table *t, const char *type,
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int dm_table_add_target(struct dm_table *t, const char *type,
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sector_t start, sector_t len, char *params)
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sector_t start, sector_t len, char *params)
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{
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{
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@ -823,6 +888,10 @@ int dm_table_complete(struct dm_table *t)
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check_for_valid_limits(&t->limits);
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check_for_valid_limits(&t->limits);
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r = validate_hardware_logical_block_alignment(t);
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if (r)
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return r;
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/* how many indexes will the btree have ? */
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/* how many indexes will the btree have ? */
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leaf_nodes = dm_div_up(t->num_targets, KEYS_PER_NODE);
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leaf_nodes = dm_div_up(t->num_targets, KEYS_PER_NODE);
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t->depth = 1 + int_log(leaf_nodes, CHILDREN_PER_NODE);
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t->depth = 1 + int_log(leaf_nodes, CHILDREN_PER_NODE);
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