pgsql: Fix race introduced by 6d46f4783efe457f74816a75173eb23ed8930020.

Fix race introduced by 6d46f4783efe457f74816a75173eb23ed8930020.

It's possible for the metapage contents to change after we release
the lock, so we must read them before releasing the lock.

Amit Kapila.  Submitted in response to a trouble report from
Andreas Seltenreich, though it is not certain this fixes the
problem.

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/2f4193c3509a822c55cc0eae77e7788806d9b022

Modified Files
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src/backend/access/hash/hashpage.c | 14 +++++++++++---
1 file changed, 11 insertions(+), 3 deletions(-)