pgsql: Fix initial sync of slot parent directory when restoring status

Fix initial sync of slot parent directory when restoring status

At the beginning of recovery, information from replication slots is
recovered from disk to memory. In order to ensure the durability of the
information, the status file as well as its parent directory are
synced. It happens that the sync on the parent directory was done
directly using the status file path, which is logically incorrect, and
the current code has been doing a sync on the same object twice in a
row.

Reported-by: Konstantin Knizhnik
Diagnosed-by: Konstantin Knizhnik
Author: Michael Paquier
Discussion: https://postgr.es/m/9eb1a6d5-b66f-2640-598d-c5ea46b8f68a@postgrespro.ru
Backpatch-through: 9.4-

Branch
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REL9_5_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/02b1b01d8ed4fad10ad4560604dc45b06968f64a

Modified Files
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src/backend/replication/slot.c | 14 +++++++-------
1 file changed, 7 insertions(+), 7 deletions(-)