NFSv4.1/pNFS: Don't request a minimal read layout beyond the end of file

If we have a read layout, then sanity check the minimal layout length
so that it does not extend beyond the end of file.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

1 files changed, 9 insertions, 0 deletions

diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
index c4f918eca3d2..ba1246433794 100644
--- a/fs/nfs/pnfs.c
+++ b/fs/nfs/pnfs.c
@@ -868,6 +868,7 @@ send_layoutget(struct pnfs_layout_hdr *lo,
         struct nfs_server *server = NFS_SERVER(ino);
         struct nfs4_layoutget *lgp;
         struct pnfs_layout_segment *lseg;
+        loff_t i_size;
 
         dprintk("--> %s\n", __func__);
 
@@ -875,9 +876,17 @@ send_layoutget(struct pnfs_layout_hdr *lo,
         if (lgp == NULL)
                 return NULL;
 
+        i_size = i_size_read(ino);
+
         lgp->args.minlength = PAGE_CACHE_SIZE;
         if (lgp->args.minlength > range->length)
                 lgp->args.minlength = range->length;
+        if (range->iomode == IOMODE_READ) {
+                if (range->offset >= i_size)
+                        lgp->args.minlength = 0;
+                else if (i_size - range->offset < lgp->args.minlength)
+                        lgp->args.minlength = i_size - range->offset;
+        }
         lgp->args.maxcount = PNFS_LAYOUT_MAXSIZE;
         lgp->args.range = *range;
         lgp->args.type = server->pnfs_curr_ld->id;