NFSv4/pNFS: Do not fail I/O when we fail to allocate the pNFS layout

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>

diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
index 856c962273c710cd860646bc6bfd7c4114770bb3..68a87be3e6f96fb4e8ab7a038d1f2bc789c05a7e 100644 (file)
--- a/fs/nfs/pnfs.c
+++ b/fs/nfs/pnfs.c
@@ -2000,6 +2000,7 @@ 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;
@@ -2128,6 +2129,7 @@ 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);