2024-02-28 00:25:05

by NeilBrown

[permalink] [raw]
Subject: [PATCH] NFS: avoid infinite loop in pnfs_update_layout.


If pnfsd_update_layout() is called on a file for which recovery has
failed it will enter a tight infinite loop.

NFS_LAYOUT_INVALID_STID will be set, nfs4_select_rw_stateid() will
return -EIO, and nfs4_schedule_stateid_recovery() will do nothing, so
nfs4_client_recover_expired_lease() will not wait. So the code will
loop indefinitely.

Break the loop by testing the validity of the open stateid at the top of
the loop.

Signed-off-by: NeilBrown <[email protected]>
---
fs/nfs/pnfs.c | 8 ++++++++
1 file changed, 8 insertions(+)

diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
index 0c0fed1ecd0b..a5cc6199127f 100644
--- a/fs/nfs/pnfs.c
+++ b/fs/nfs/pnfs.c
@@ -1999,6 +1999,14 @@ pnfs_update_layout(struct inode *ino,
}

lookup_again:
+ if (!nfs4_valid_open_stateid(ctx->state)) {
+ trace_pnfs_update_layout(ino, pos, count,
+ iomode, lo, lseg,
+ PNFS_UPDATE_LAYOUT_INVALID_OPEN);
+ lseg = ERR_PTR(-EIO);
+ goto out;
+ }
+
lseg = ERR_PTR(nfs4_client_recover_expired_lease(clp));
if (IS_ERR(lseg))
goto out;
--
2.43.0