svn commit: r328847 - stable/11/sys/kern

[Andriy Gapon]

Author: avg
Date: Sun Feb  4 14:00:38 2018
New Revision: 328847
URL: https://svnweb.freebsd.org/changeset/base/328847

Log:
  MFC r328126: correct read-ahead calculations in vfs_bio_getpages

Modified:
  stable/11/sys/kern/vfs_bio.c
Directory Properties:
  stable/11/   (props changed)

Modified: stable/11/sys/kern/vfs_bio.c
==============================================================================
--- stable/11/sys/kern/vfs_bio.c	Sun Feb  4 13:58:31 2018	(r328846)
+++ stable/11/sys/kern/vfs_bio.c	Sun Feb  4 14:00:38 2018	(r328847)
@@ -4764,7 +4764,14 @@ vfs_bio_getpages(struct vnode *vp, vm_page_t *ma, int 
 	la = IDX_TO_OFF(ma[count - 1]->pindex);
 	if (la >= object->un_pager.vnp.vnp_size)
 		return (VM_PAGER_BAD);
-	lpart = la + PAGE_SIZE > object->un_pager.vnp.vnp_size;
+
+	/*
+	 * Change the meaning of la from where the last requested page starts
+	 * to where it ends, because that's the end of the requested region
+	 * and the start of the potential read-ahead region.
+	 */
+	la += PAGE_SIZE;
+	lpart = la > object->un_pager.vnp.vnp_size;
 	bo_bs = get_blksize(vp, get_lblkno(vp, IDX_TO_OFF(ma[0]->pindex)));
 
 	/*