From: Matthew Dillon <dillon@apollo.backplane.com>
Date: Sat, 14 Aug 2010 17:53:43 +0000 (-0700)
Subject: kernel - flag when bogus_page's are present
X-Git-Tag: v2.9.0~533
X-Git-Url: https://gitweb.dragonflybsd.org/dragonfly.git/commitdiff_plain/e158420cacc687adbb028becd3750427f0f25873

kernel - flag when bogus_page's are present

* Flag a buffer when bogus pages are present.  Add B_HASBOGUS to b_flags.

  Certain in-place read operations, such as decryption, must allocate a
  copy if the original buffer contains bogus pages.
---

diff --git a/sys/kern/vfs_bio.c b/sys/kern/vfs_bio.c
index 26d7a8b61f..13b128b0fc 100644
--- a/sys/kern/vfs_bio.c
+++ b/sys/kern/vfs_bio.c
@@ -1399,6 +1399,7 @@ brelse(struct buf *bp)
 						bp->b_xio.xio_pages[j] = mtmp;
 					}
 				}
+				bp->b_flags &= ~B_HASBOGUS;
 
 				if ((bp->b_flags & B_INVAL) == 0) {
 					pmap_qenter(trunc_page((vm_offset_t)bp->b_data),
@@ -3704,6 +3705,7 @@ bpdone(struct buf *bp, int elseit)
 			foff = (foff + PAGE_SIZE) & ~(off_t)PAGE_MASK;
 			iosize -= resid;
 		}
+		bp->b_flags &= ~B_HASBOGUS;
 		if (obj)
 			vm_object_pip_wakeupn(obj, 0);
 		rel_mplock();
@@ -3839,6 +3841,7 @@ vfs_unbusy_pages(struct buf *bp)
 			vm_page_flag_clear(m, PG_ZERO);
 			vm_page_io_finish(m);
 		}
+		bp->b_flags &= ~B_HASBOGUS;
 		vm_object_pip_wakeupn(obj, 0);
 	}
 }
@@ -3962,6 +3965,7 @@ retry:
 				 * this also covers the dirty case.
 				 */
 				bp->b_xio.xio_pages[i] = bogus_page;
+				bp->b_flags |= B_HASBOGUS;
 				bogus++;
 			} else if (m->valid & m->dirty) {
 				/*
diff --git a/sys/sys/buf.h b/sys/sys/buf.h
index c12bc52828..ea87d42ebd 100644
--- a/sys/sys/buf.h
+++ b/sys/sys/buf.h
@@ -293,7 +293,7 @@ struct buf {
 #define	B_HASHED 	0x00000040 	/* Indexed via v_rbhash_tree */
 #define	B_DELWRI	0x00000080	/* Delay I/O until buffer reused. */
 #define	B_BNOCLIP	0x00000100	/* EOF clipping b_bcount not allowed */
-#define	B_UNUSED9	0x00000200
+#define	B_HASBOGUS	0x00000200	/* Contains bogus pages */
 #define	B_EINTR		0x00000400	/* I/O was interrupted */
 #define	B_ERROR		0x00000800	/* I/O error occurred. */
 #define	B_UNUSED12	0x00001000	/* Unused */