ceph: fix writeback_count leak when a bounce page allocation fails

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ceph_process_folio_batch() calls is_write_congestion_happened(), which
increments fsc->writeback_count, before calling
move_dirty_folio_in_page_array(). If the fscrypt bounce page allocation
there fails, the folio is redirtied and never makes it into the page
array, but the count is never dropped.

write_congested is only cleared when a decrement falls below
CONGESTION_OFF_THRESH, so the leaked counts set congestion early and
eventually leave write_congested set for good. Every WB_SYNC_NONE
writeback then returns 0 and background writeback stops entirely.

Bump the count only once the folio is in the page array.

Fixes: d55207717d ("ceph: add encryption support to writepage and writepages")
Reported-by: Sashiko <sashiko-bot@kernel.org>
Link: https://sashiko.dev/#/patchset/20260902-remove-wait-on-page-writeback-v5-0-0b512e77e75b%40columbia.edu?part=1
Assisted-by: Claude:fable-5.1
Signed-off-by: Tal Zussman <tz2294@columbia.edu>
Reviewed-by: Alex Markuze <amarkuze@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

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Tal Zussman 2026-09-07 15:38:19 +00:00 • committed by Ilya Dryomov

parent 979b7ed445

commit 7807710d88

1 changed files with 2 additions and 2 deletions

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fs/ceph/addr.c

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