[Xen-devel] [PATCH] blktap2: Invalid logic detecting unaligned buffers in vhd_write_block

[Ross Philipson <ross.philipson@xxxxxxxxx>]

It seems the logic is meant to detect sector unaligned buffers for block
writes. The NOTing of the logic instead masks off any unaligned bits and
also would cause the function to always fail. It seems the function is not
used in any of the tools so that is probably why the problem is not seen.
In the vhd_read_block function it is correct.

Signed-off-by: Ross Philipson <ross.philipson@xxxxxxxxxxxx>
---
diff --git a/tools/blktap2/vhd/lib/libvhd.c b/tools/blktap2/vhd/lib/libvhd.c
index 1fd5b4e..4ebe012 100644
--- a/tools/blktap2/vhd/lib/libvhd.c
+++ b/tools/blktap2/vhd/lib/libvhd.c
@@ -2188,7 +2188,7 @@ vhd_write_block(vhd_context_t *ctx, uint32_t block, char 
*data)
        if (block >= ctx->bat.entries)
                return -ERANGE;

-       if ((unsigned long)data & ~(VHD_SECTOR_SIZE -1))
+       if ((unsigned long)data & (VHD_SECTOR_SIZE -1))
                return -EINVAL;

        blk  = ctx->bat.bat[block];

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