pnfs: filelayout: support non page aligned layouts

Use the new pg_test interface to adjust requests to fit in the current
stripe / segment.

Signed-off-by: Weston Andros Adamson <dros@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

1 files changed, 20 insertions, 32 deletions

diff --git a/fs/nfs/nfs4filelayout.c b/fs/nfs/nfs4filelayout.c
index 0ebc521ea6fc..63a16375660a 100644
--- a/fs/nfs/nfs4filelayout.c
+++ b/fs/nfs/nfs4filelayout.c
@@ -639,7 +639,6 @@ filelayout_check_layout(struct pnfs_layout_hdr *lo,
         struct nfs4_deviceid_node *d;
         struct nfs4_file_layout_dsaddr *dsaddr;
         int status = -EINVAL;
-        struct nfs_server *nfss = NFS_SERVER(lo->plh_inode);
 
         dprintk("--> %s\n", __func__);
 
@@ -657,7 +656,7 @@ filelayout_check_layout(struct pnfs_layout_hdr *lo,
                 goto out;
         }
 
-        if (!fl->stripe_unit || fl->stripe_unit % PAGE_SIZE) {
+        if (!fl->stripe_unit) {
                 dprintk("%s Invalid stripe unit (%u)\n",
                         __func__, fl->stripe_unit);
                 goto out;
@@ -694,12 +693,6 @@ filelayout_check_layout(struct pnfs_layout_hdr *lo,
                 goto out_put;
         }
 
-        if (fl->stripe_unit % nfss->rsize || fl->stripe_unit % nfss->wsize) {
-                dprintk("%s Stripe unit (%u) not aligned with rsize %u "
-                        "wsize %u\n", __func__, fl->stripe_unit, nfss->rsize,
-                        nfss->wsize);
-        }
-
         status = 0;
 out:
         dprintk("--> %s returns %d\n", __func__, status);
@@ -936,44 +929,42 @@ filelayout_pg_test(struct nfs_pageio_descriptor *pgio, struct nfs_page *prev,
 {
         unsigned int size;
         u64 p_stripe, r_stripe;
-        u32 stripe_unit;
+        u32 stripe_offset;
+        u64 segment_offset = pgio->pg_lseg->pls_range.offset;
+        u32 stripe_unit = FILELAYOUT_LSEG(pgio->pg_lseg)->stripe_unit;
 
         /* calls nfs_generic_pg_test */
         size = pnfs_generic_pg_test(pgio, prev, req);
         if (!size)
                 return 0;
 
+        /* see if req and prev are in the same stripe */
         if (prev) {
-                p_stripe = (u64)req_offset(prev);
-                r_stripe = (u64)req_offset(req);
-                stripe_unit = FILELAYOUT_LSEG(pgio->pg_lseg)->stripe_unit;
-
+                p_stripe = (u64)req_offset(prev) - segment_offset;
+                r_stripe = (u64)req_offset(req) - segment_offset;
                 do_div(p_stripe, stripe_unit);
                 do_div(r_stripe, stripe_unit);
 
                 if (p_stripe != r_stripe)
                         return 0;
         }
-        return min(size, req->wb_bytes);
+
+        /* calculate remaining bytes in the current stripe */
+        div_u64_rem((u64)req_offset(req) - segment_offset,
+                        stripe_unit,
+                        &stripe_offset);
+        WARN_ON_ONCE(stripe_offset > stripe_unit);
+        if (stripe_offset >= stripe_unit)
+                return 0;
+        return min(stripe_unit - (unsigned int)stripe_offset, size);
 }
 
 static void
 filelayout_pg_init_read(struct nfs_pageio_descriptor *pgio,
                         struct nfs_page *req)
 {
-        WARN_ON_ONCE(pgio->pg_lseg != NULL);
-
-        if (req->wb_offset != req->wb_pgbase) {
-                /*
-                 * Handling unaligned pages is difficult, because have to
-                 * somehow split a req in two in certain cases in the
-                 * pg.test code.  Avoid this by just not using pnfs
-                 * in this case.
-                 */
-                nfs_pageio_reset_read_mds(pgio);
-                return;
-        }
-        pgio->pg_lseg = pnfs_update_layout(pgio->pg_inode,
+        if (!pgio->pg_lseg)
+                pgio->pg_lseg = pnfs_update_layout(pgio->pg_inode,
                                            req->wb_context,
                                            0,
                                            NFS4_MAX_UINT64,
@@ -991,11 +982,8 @@ filelayout_pg_init_write(struct nfs_pageio_descriptor *pgio,
         struct nfs_commit_info cinfo;
         int status;
 
-        WARN_ON_ONCE(pgio->pg_lseg != NULL);
-
-        if (req->wb_offset != req->wb_pgbase)
-                goto out_mds;
-        pgio->pg_lseg = pnfs_update_layout(pgio->pg_inode,
+        if (!pgio->pg_lseg)
+                pgio->pg_lseg = pnfs_update_layout(pgio->pg_inode,
                                            req->wb_context,
                                            0,
                                            NFS4_MAX_UINT64,