forked from Minki/linux
dm thin: fix non power of two discard granularity calc
Fix a discard granularity calculation to work for non power of 2 block sizes.
In order for thinp to passdown discard bios to the underlying data
device, the data device must have a discard granularity that is a
factor of the thinp block size. Originally this check was done by
using bitops since the block_size was known to be a power of two.
Introduced by commit f13945d757
("dm thin: support a non power of 2 discard_granularity").
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
This commit is contained in:
parent
f046f89a99
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@ -1577,6 +1577,11 @@ static bool data_dev_supports_discard(struct pool_c *pt)
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return q && blk_queue_discard(q);
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}
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static bool is_factor(sector_t block_size, uint32_t n)
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{
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return !sector_div(block_size, n);
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}
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/*
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* If discard_passdown was enabled verify that the data device
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* supports discards. Disable discard_passdown if not.
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@ -1602,7 +1607,7 @@ static void disable_passdown_if_not_supported(struct pool_c *pt)
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else if (data_limits->discard_granularity > block_size)
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reason = "discard granularity larger than a block";
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else if (block_size & (data_limits->discard_granularity - 1))
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else if (!is_factor(block_size, data_limits->discard_granularity))
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reason = "discard granularity not a factor of block size";
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if (reason) {
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