[PATCH 6/9] NFSv4/flexfiles: Commit path updates for striped layouts

[Jonathan Curley <jcurley@purestorage.com>]

Updates the commit path to be stripe aware. This required updating
the ds_commit_idx to be stripe aware.

ds_commit_idx == mirror_idx * dss_count + dss_id.

Updates code paths to utilize the new ds_commit_idx and derive dss_id
& mirror_idx where appropriate to contact the correct DS using the
corresponding parameters.

Signed-off-by: Jonathan Curley <jcurley@purestorage.com>
---
 fs/nfs/flexfilelayout/flexfilelayout.c | 49 +++++++++++++++++---------
 1 file changed, 33 insertions(+), 16 deletions(-)

diff --git a/fs/nfs/flexfilelayout/flexfilelayout.c b/fs/nfs/flexfilelayout/flexfilelayout.c
index 79700c18762c..b0d870359536 100644
--- a/fs/nfs/flexfilelayout/flexfilelayout.c
+++ b/fs/nfs/flexfilelayout/flexfilelayout.c
@@ -605,6 +605,26 @@ ff_layout_free_lseg(struct pnfs_layout_segment *lseg)
 	_ff_layout_free_lseg(fls);
 }
 
+static u32 calc_mirror_idx_from_commit(struct pnfs_layout_segment *lseg,
+				       u32 commit_index)
+{
+	struct nfs4_ff_layout_segment *flseg = FF_LAYOUT_LSEG(lseg);
+	u32 mirror_idx = commit_index;
+
+	do_div(mirror_idx, flseg->mirror_array[0]->dss_count);
+
+	return mirror_idx;
+}
+
+static u32 calc_dss_id_from_commit(struct pnfs_layout_segment *lseg,
+				   u32 commit_index)
+{
+	struct nfs4_ff_layout_segment *flseg = FF_LAYOUT_LSEG(lseg);
+	u32 mirror_idx = commit_index;
+
+	return do_div(mirror_idx, flseg->mirror_array[0]->dss_count);
+}
+
 static void
 nfs4_ff_start_busy_timer(struct nfs4_ff_busy_timer *timer, ktime_t now)
 {
@@ -2094,20 +2114,15 @@ ff_layout_write_pagelist(struct nfs_pgio_header *hdr, int sync)
 	return PNFS_NOT_ATTEMPTED;
 }
 
-static u32 calc_ds_index_from_commit(struct pnfs_layout_segment *lseg, u32 i)
-{
-	return i;
-}
-
 static struct nfs_fh *
-select_ds_fh_from_commit(struct pnfs_layout_segment *lseg, u32 i)
+select_ds_fh_from_commit(struct pnfs_layout_segment *lseg, u32 i, u32 dss_id)
 {
 	struct nfs4_ff_layout_segment *flseg = FF_LAYOUT_LSEG(lseg);
 
 	/* FIXME: Assume that there is only one NFS version available
 	 * for the DS.
 	 */
-	return &flseg->mirror_array[i]->dss[0].fh_versions[0];
+	return &flseg->mirror_array[i]->dss[dss_id].fh_versions[0];
 }
 
 static int ff_layout_initiate_commit(struct nfs_commit_data *data, int how)
@@ -2118,7 +2133,7 @@ static int ff_layout_initiate_commit(struct nfs_commit_data *data, int how)
 	struct nfsd_file *localio;
 	struct nfs4_ff_layout_mirror *mirror;
 	const struct cred *ds_cred;
-	u32 idx;
+	u32 idx, dss_id;
 	int vers, ret;
 	struct nfs_fh *fh;
 
@@ -2126,22 +2141,23 @@ static int ff_layout_initiate_commit(struct nfs_commit_data *data, int how)
 	    test_bit(NFS_LSEG_LAYOUTRETURN, &lseg->pls_flags)))
 		goto out_err;
 
-	idx = calc_ds_index_from_commit(lseg, data->ds_commit_index);
+	idx = calc_mirror_idx_from_commit(lseg, data->ds_commit_index);
 	mirror = FF_LAYOUT_COMP(lseg, idx);
-	ds = nfs4_ff_layout_prepare_ds(lseg, mirror, 0, true);
+	dss_id = calc_dss_id_from_commit(lseg, data->ds_commit_index);
+	ds = nfs4_ff_layout_prepare_ds(lseg, mirror, dss_id, true);
 	if (!ds)
 		goto out_err;
 
 	ds_clnt = nfs4_ff_find_or_create_ds_client(mirror, ds->ds_clp,
-						   data->inode, 0);
+						   data->inode, dss_id);
 	if (IS_ERR(ds_clnt))
 		goto out_err;
 
-	ds_cred = ff_layout_get_ds_cred(mirror, &lseg->pls_range, data->cred, 0);
+	ds_cred = ff_layout_get_ds_cred(mirror, &lseg->pls_range, data->cred, dss_id);
 	if (!ds_cred)
 		goto out_err;
 
-	vers = nfs4_ff_layout_ds_version(mirror, 0);
+	vers = nfs4_ff_layout_ds_version(mirror, dss_id);
 
 	dprintk("%s ino %lu, how %d cl_count %d vers %d\n", __func__,
 		data->inode->i_ino, how, refcount_read(&ds->ds_clp->cl_count),
@@ -2150,12 +2166,12 @@ static int ff_layout_initiate_commit(struct nfs_commit_data *data, int how)
 	data->cred = ds_cred;
 	refcount_inc(&ds->ds_clp->cl_count);
 	data->ds_clp = ds->ds_clp;
-	fh = select_ds_fh_from_commit(lseg, data->ds_commit_index);
+	fh = select_ds_fh_from_commit(lseg, idx, dss_id);
 	if (fh)
 		data->args.fh = fh;
 
 	/* Start IO accounting for local commit */
-	localio = ff_local_open_fh(lseg, idx, 0, ds->ds_clp, ds_cred, fh,
+	localio = ff_local_open_fh(lseg, idx, dss_id, ds->ds_clp, ds_cred, fh,
 				   FMODE_READ|FMODE_WRITE);
 	if (localio) {
 		data->task.tk_start = ktime_get();
@@ -2259,8 +2275,9 @@ ff_layout_setup_ds_info(struct pnfs_ds_commit_info *fl_cinfo,
 	struct nfs4_ff_layout_segment *flseg = FF_LAYOUT_LSEG(lseg);
 	struct inode *inode = lseg->pls_layout->plh_inode;
 	struct pnfs_commit_array *array, *new;
+	u32 size = flseg->mirror_array_cnt * flseg->mirror_array[0]->dss_count;
 
-	new = pnfs_alloc_commit_array(flseg->mirror_array_cnt,
+	new = pnfs_alloc_commit_array(size,
 				      nfs_io_gfp_mask());
 	if (new) {
 		spin_lock(&inode->i_lock);
-- 
2.34.1