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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Olga Kornievskaia <aglo@umich.edu>,
        Trond Myklebust <trond.myklebust@hammerspace.com>,
        Anna Schumaker <Anna.Schumaker@Netapp.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.15 498/667] NFSv4/pNFS: Do not fail I/O when we fail to allocate the pNFS layout
Date:   Tue,  7 Jun 2022 19:02:43 +0200
Message-Id: <20220607164949.635381183@linuxfoundation.org>
In-Reply-To: <20220607164934.766888869@linuxfoundation.org>
References: <20220607164934.766888869@linuxfoundation.org>
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From: Trond Myklebust <trond.myklebust@hammerspace.com>

[ Upstream commit 3764a17e31d579cf9b4bd0a69894b577e8d75702 ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/nfs/pnfs.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
index 7ddd003ab8b1..9203a17b3f09 100644
--- a/fs/nfs/pnfs.c
+++ b/fs/nfs/pnfs.c
@@ -2000,6 +2000,7 @@ pnfs_update_layout(struct inode *ino,
 	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;
@@ -2128,6 +2129,7 @@ pnfs_update_layout(struct inode *ino,
 
 	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);
-- 
2.35.1