From: Trond Myklebust <trond.myklebust@hammerspace.com>
Date: Sat, 14 May 2022 10:08:11 -0400
Subject: [PATCH] NFSv4/pNFS: Do not fail I/O when we fail to allocate the pNFS
 layout
Git-commit: 3764a17e31d579cf9b4bd0a69894b577e8d75702
Patch-mainline: v5.19
References: git-fixes

Commit 587f03deb69b caused pnfs_update_layout() to stop returning ENOMEM
when the memory allocation fails, and hence causes it to fall back to
trying to do I/O through the MDS. There is no guarantee that this will
fare any better. If we're failing the pNFS layout allocation, then we
should just redirty the page and retry later.

Reported-by: Olga Kornievskaia <aglo@umich.edu>
Fixes: 587f03deb69b ("pnfs: refactor send_layoutget")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Acked-by: NeilBrown <neilb@suse.com>

---
 fs/nfs/pnfs.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/fs/nfs/pnfs.c
+++ b/fs/nfs/pnfs.c
@@ -2004,6 +2004,7 @@ lookup_again:
 	lo = pnfs_find_alloc_layout(ino, ctx, gfp_flags);
 	if (lo == NULL) {
 		spin_unlock(&ino->i_lock);
+		lseg = ERR_PTR(-ENOMEM);
 		trace_pnfs_update_layout(ino, pos, count, iomode, lo, lseg,
 				 PNFS_UPDATE_LAYOUT_NOMEM);
 		goto out;
@@ -2132,6 +2133,7 @@ lookup_again:
 
 	lgp = pnfs_alloc_init_layoutget_args(ino, ctx, &stateid, &arg, gfp_flags);
 	if (!lgp) {
+		lseg = ERR_PTR(-ENOMEM);
 		trace_pnfs_update_layout(ino, pos, count, iomode, lo, NULL,
 					 PNFS_UPDATE_LAYOUT_NOMEM);
 		nfs_layoutget_end(lo);