pgsql: bufmgr: Fix signedness of mask variable in BufferSync()

bufmgr: Fix signedness of mask variable in BufferSync()

BM_PERMANENT is defined as 1U<<31, which is a negative number when interpreted
as a signed integer. Unfortunately the mask variable in BufferSync() was
signed. This has been wrong for a long time, but failed to fail, due to
integer conversion rules.

However, in an upcoming patch the width of the state variable will be
increased, with the wrong signedness leading to never flushing permanent
buffers - luckily caught in a test.

It seems better to fix this separately, instead of doing so as part of a
large, otherwise mechanical, patch.

Reviewed-by: Matthias van de Meent <boekewurm+postgres@gmail.com>
Discussion: https://postgr.es/m/fvfmkr5kk4nyex56ejgxj3uzi63isfxovp2biecb4bspbjrze7@az2pljabhnff

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/2a2e1b470b9b4e9c7d76bc227db02a2efbb57473

Modified Files
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src/backend/storage/buffer/bufmgr.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)