diff options
| author | Benjamin Coddington <bcodding@redhat.com> | 2025-06-19 11:02:21 -0400 |
|---|---|---|
| committer | Anna Schumaker <anna.schumaker@oracle.com> | 2025-06-23 11:01:16 -0400 |
| commit | c01776287414ca43412d1319d2877cbad65444ac (patch) | |
| tree | fd06f5bb4f6b98c062d3819cfa5f94972887160f | |
| parent | e8d6f3ab59468e230f3253efe5cb63efa35289f7 (diff) | |
NFSv4/pNFS: Fix a race to wake on NFS_LAYOUT_DRAIN
We found a few different systems hung up in writeback waiting on the same
page lock, and one task waiting on the NFS_LAYOUT_DRAIN bit in
pnfs_update_layout(), however the pnfs_layout_hdr's plh_outstanding count
was zero.
It seems most likely that this is another race between the waiter and waker
similar to commit ed0172af5d6f ("SUNRPC: Fix a race to wake a sync task").
Fix it up by applying the advised barrier.
Fixes: 880265c77ac4 ("pNFS: Avoid a live lock condition in pnfs_update_layout()")
Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Anna Schumaker <anna.schumaker@oracle.com>
| -rw-r--r-- | fs/nfs/pnfs.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c index 3adb7d0dbec7..1a7ec68bde15 100644 --- a/fs/nfs/pnfs.c +++ b/fs/nfs/pnfs.c @@ -2059,8 +2059,10 @@ static void nfs_layoutget_begin(struct pnfs_layout_hdr *lo) static void nfs_layoutget_end(struct pnfs_layout_hdr *lo) { if (atomic_dec_and_test(&lo->plh_outstanding) && - test_and_clear_bit(NFS_LAYOUT_DRAIN, &lo->plh_flags)) + test_and_clear_bit(NFS_LAYOUT_DRAIN, &lo->plh_flags)) { + smp_mb__after_atomic(); wake_up_bit(&lo->plh_flags, NFS_LAYOUT_DRAIN); + } } static bool pnfs_is_first_layoutget(struct pnfs_layout_hdr *lo) |