Merge v7.1.5linux-rolling-stable

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

2 files changed, 45 insertions, 0 deletions

diff --git a/fs/nfs/flexfilelayout/flexfilelayout.c b/fs/nfs/flexfilelayout/flexfilelayout.c
index e22a8e0daf2c..2e7f857d5a8c 100644
--- a/fs/nfs/flexfilelayout/flexfilelayout.c
+++ b/fs/nfs/flexfilelayout/flexfilelayout.c
@@ -636,6 +636,9 @@ ff_layout_alloc_lseg(struct pnfs_layout_hdr *lh,
 	if (!p)
 		goto out_sort_mirrors;
 	fls->flags = be32_to_cpup(p);
+	if (fls->flags & FF_FLAGS_NO_IO_THRU_MDS)
+		set_bit(NFS4_FF_HDR_NO_IO_THRU_MDS,
+			&FF_LAYOUT_FROM_HDR(lh)->flags);
 
 	p = xdr_inline_decode(&stream, 4);
 	if (!p)
@@ -1185,6 +1188,16 @@ ff_layout_pg_get_mirror_count_write(struct nfs_pageio_descriptor *pgio,
 			0, NFS4_MAX_UINT64, IOMODE_RW,
 			NFS_I(pgio->pg_inode)->layout,
 			pgio->pg_lseg);
+	if (NFS_I(pgio->pg_inode)->layout &&
+	    ff_layout_hdr_no_fallback_to_mds(NFS_I(pgio->pg_inode)->layout)) {
+		/*
+		 * FF_FLAGS_NO_IO_THRU_MDS: no current lseg but the server's
+		 * policy forbids MDS fallback.  Surface -EAGAIN so writeback
+		 * retries rather than silently issuing the WRITE via MDS.
+		 */
+		pgio->pg_error = -EAGAIN;
+		goto out;
+	}
 	/* no lseg means that pnfs is not in use, so no mirroring here */
 	nfs_pageio_reset_write_mds(pgio);
 out:
@@ -2204,6 +2217,14 @@ ff_layout_read_pagelist(struct nfs_pgio_header *hdr)
 out_failed:
 	if (ff_layout_avoid_mds_available_ds(lseg) && !ds_fatal_error)
 		return PNFS_TRY_AGAIN;
+	if (ff_layout_no_fallback_to_mds(lseg)) {
+		/*
+		 * FF_FLAGS_NO_IO_THRU_MDS: force fresh LAYOUTGET,
+		 * never fall through to MDS I/O.
+		 */
+		pnfs_error_mark_layout_for_return(hdr->inode, lseg);
+		return PNFS_TRY_AGAIN;
+	}
 	trace_pnfs_mds_fallback_read_pagelist(hdr->inode,
 			hdr->args.offset, hdr->args.count,
 			IOMODE_READ, NFS_I(hdr->inode)->layout, lseg);
@@ -2289,6 +2310,14 @@ ff_layout_write_pagelist(struct nfs_pgio_header *hdr, int sync)
 out_failed:
 	if (ff_layout_avoid_mds_available_ds(lseg) && !ds_fatal_error)
 		return PNFS_TRY_AGAIN;
+	if (ff_layout_no_fallback_to_mds(lseg)) {
+		/*
+		 * FF_FLAGS_NO_IO_THRU_MDS: force fresh LAYOUTGET,
+		 * never fall through to MDS I/O.
+		 */
+		pnfs_error_mark_layout_for_return(hdr->inode, lseg);
+		return PNFS_TRY_AGAIN;
+	}
 	trace_pnfs_mds_fallback_write_pagelist(hdr->inode,
 			hdr->args.offset, hdr->args.count,
 			IOMODE_RW, NFS_I(hdr->inode)->layout, lseg);
diff --git a/fs/nfs/flexfilelayout/flexfilelayout.h b/fs/nfs/flexfilelayout/flexfilelayout.h
index 17a008c8e97c..a5bd00f69e82 100644
--- a/fs/nfs/flexfilelayout/flexfilelayout.h
+++ b/fs/nfs/flexfilelayout/flexfilelayout.h
@@ -112,12 +112,16 @@ struct nfs4_ff_layout_segment {
 	struct nfs4_ff_layout_mirror	*mirror_array[] __counted_by(mirror_array_cnt);
 };
 
+/* nfs4_flexfile_layout::flags bit indices */
+#define NFS4_FF_HDR_NO_IO_THRU_MDS  0   /* any lseg has had FF_FLAGS_NO_IO_THRU_MDS */
+
 struct nfs4_flexfile_layout {
 	struct pnfs_layout_hdr generic_hdr;
 	struct pnfs_ds_commit_info commit_info;
 	struct list_head	mirrors;
 	struct list_head	error_list; /* nfs4_ff_layout_ds_err */
 	ktime_t			last_report_time; /* Layoutstat report times */
+	unsigned long		flags;
 };
 
 struct nfs4_flexfile_layoutreturn_args {
@@ -184,6 +188,18 @@ ff_layout_no_fallback_to_mds(struct pnfs_layout_segment *lseg)
 	return FF_LAYOUT_LSEG(lseg)->flags & FF_FLAGS_NO_IO_THRU_MDS;
 }
 
+/*
+ * Sticky hdr-level mirror of FF_FLAGS_NO_IO_THRU_MDS so callers that have
+ * no current lseg (e.g. between LAYOUTRETURN and the next LAYOUTGET) can
+ * still honor the no-MDS-fallback policy.
+ */
+static inline bool
+ff_layout_hdr_no_fallback_to_mds(struct pnfs_layout_hdr *lo)
+{
+	return test_bit(NFS4_FF_HDR_NO_IO_THRU_MDS,
+			&FF_LAYOUT_FROM_HDR(lo)->flags);
+}
+
 static inline bool
 ff_layout_no_read_on_rw(struct pnfs_layout_segment *lseg)
 {