Avoid reporting a capacity that is too big if the LIO device block
size is larger than the block device block size. Avoid reporting a
capacity that is too small if the LIO device block size is smaller
than the block device block size.
Untested, hence posting this as an RFC.
Signed-off-by: Bart Van Assche <bart.vanassche@xxxxxxxxxxx>
---
drivers/target/target_core_iblock.c | 78 ++++---------------------------------
1 file changed, 7 insertions(+), 71 deletions(-)
diff --git a/drivers/target/target_core_iblock.c b/drivers/target/target_core_iblock.c
index 6d88d24..8c78782 100644
--- a/drivers/target/target_core_iblock.c
+++ b/drivers/target/target_core_iblock.c
@@ -210,83 +210,19 @@ static void iblock_free_device(struct se_device *dev)
call_rcu(&dev->rcu_head, iblock_dev_call_rcu);
}
+/*
+ * Return one less than the capacity as a number of blocks. If the block device
+ * block size and the LIO device block size are different and if the capacity
+ * is not a multiple of the LIO device block size, round down.
+ */
static unsigned long long iblock_emulate_read_cap_with_block_size(
struct se_device *dev,
struct block_device *bd,
struct request_queue *q)
{
- unsigned long long blocks_long = (div_u64(i_size_read(bd->bd_inode),
- bdev_logical_block_size(bd)) - 1);
- u32 block_size = bdev_logical_block_size(bd);
-
- if (block_size == dev->dev_attrib.block_size)
- return blocks_long;
-
- switch (block_size) {
- case 4096:
- switch (dev->dev_attrib.block_size) {
- case 2048:
- blocks_long <<= 1;
- break;
- case 1024:
- blocks_long <<= 2;
- break;
- case 512:
- blocks_long <<= 3;
- default:
- break;
- }
- break;
- case 2048:
- switch (dev->dev_attrib.block_size) {
- case 4096:
- blocks_long >>= 1;
- break;
- case 1024:
- blocks_long <<= 1;
- break;
- case 512:
- blocks_long <<= 2;
- break;
- default:
- break;
- }
- break;
- case 1024:
- switch (dev->dev_attrib.block_size) {
- case 4096:
- blocks_long >>= 2;
- break;
- case 2048:
- blocks_long >>= 1;
- break;
- case 512:
- blocks_long <<= 1;
- break;
- default:
- break;
- }
- break;
- case 512:
- switch (dev->dev_attrib.block_size) {
- case 4096:
- blocks_long >>= 3;
- break;
- case 2048:
- blocks_long >>= 2;
- break;
- case 1024:
- blocks_long >>= 1;
- break;
- default:
- break;
- }
- break;
- default:
- break;
- }
+ unsigned bs = dev->dev_attrib.block_size;
- return blocks_long;
+ return (i_size_read(bd->bd_inode) >> ilog2(bs)) - 1;
}
static void iblock_complete_cmd(struct se_cmd *cmd)
--
2.1.4
--
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