5d07384a66
A reload of the cache's DM table is needed during resize because
otherwise a crash will occur when attempting to access smq policy
entries associated with the portion of the cache that was recently
extended.
The reason is cache-size based data structures in the policy will not be
resized, the only way to safely extend the cache is to allow for a
proper cache policy initialization that occurs when the cache table is
loaded. For example the smq policy's space_init(), init_allocator(),
calc_hotspot_params() must be sized based on the extended cache size.
The fix for this is to disallow cache resizes of this pattern:
1) suspend "cache" target's device
2) resize the fast device used for the cache
3) resume "cache" target's device
Instead, the last step must be a full reload of the cache's DM table.
Fixes: 66a636356 ("dm cache: add stochastic-multi-queue (smq) policy")
Cc: stable@vger.kernel.org
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Linux kernel
============
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In order to build the documentation, use ``make htmldocs`` or
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https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.
Please read the Documentation/process/changes.rst file, as it contains the
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the problems which may result by upgrading your kernel.