nfs/localio: add refcounting for each iocb IO associated with NFS pgio header

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Improve completion handling of as many as 3 IOs associated with each
misaligned DIO by using a atomic_t to track completion of each IO.

Update nfs_local_pgio_done() to use precise atomic_t accounting for
remaining iov_iter (up to 3) associated with each iocb, so that each
NFS LOCALIO pgio header is only released after all IOs have completed.
But also allow early return if/when a short read or write occurs.

Fixes reported BUG: KASAN: slab-use-after-free in nfs_local_call_read:
https://lore.kernel.org/linux-nfs/aPSvi5Yr2lGOh5Jh@dell-per750-06-vm-07.rhts.eng.pek2.redhat.com/

Reported-by: Yongcheng Yang <yoyang@redhat.com>
Fixes: c817248fc8 ("nfs/localio: add proper O_DIRECT support for READ and WRITE")
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: Anna Schumaker <anna.schumaker@oracle.com>

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Mike Snitzer 2025-10-27 09:08:32 -04:00 • committed by Anna Schumaker

parent 51a491f270

commit f2060bdc21

1 changed files with 67 additions and 43 deletions

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fs/nfs/localio.c

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