Add a new struct buf flag bit, B_PERSISTENT, and use it to tag

struct bufs that are persistently held by ext2fs.  Ignore any buffers
with this flag in the code in boot() that counts "busy" and dirty
buffers and attempts to sync the dirty buffers, which is done before
attempting to unmount all the file systems during shutdown.

This fixes the problem caused by any ext2fs file systems that are
mounted at system shutdown time, which caused boot() to give up on
a non-zero number of buffers and skip the call to vfs_unmountall().
This left all the mounted file systems in a dirty state and caused
them to all require cleanup by fsck on reboot.

Move the two separate copies of the "busy" buffer test in boot()
to a separate function.

Nuke the useless spl() stuff in the ext2fs ULCK_BUF() macro.

Bring the PRINT_BUF_FLAGS definition in sys/buf.h up to date with
this and previous flag changes.

PR:		kern/56675, kern/85163
Tested by:	"Matthias Andree" matthias.andree at gmx.de
Reviewed by:	bde
MFC after:	3 days

1 files changed, 13 insertions, 11 deletions

diff --git a/sys/kern/kern_shutdown.c b/sys/kern/kern_shutdown.c
index a22cea2..9b70f18 100644
--- a/sys/kern/kern_shutdown.c
+++ b/sys/kern/kern_shutdown.c
@@ -236,6 +236,16 @@ doadump(void)
 	dumpsys(&dumper);
 }
 
+static int
+isbufbusy(struct buf *bp)
+{
+	if (((bp->b_flags & (B_INVAL | B_PERSISTENT)) == 0 &&
+	    BUF_REFCNT(bp) > 0) ||
+	    ((bp->b_flags & (B_DELWRI | B_INVAL)) == B_DELWRI))
+		return (1);
+	return (0);
+}
+
 /*
  * Shutdown the system cleanly to prepare for reboot, halt, or power off.
  */
@@ -288,16 +298,9 @@ boot(int howto)
 		 */
 		for (iter = pbusy = 0; iter < 20; iter++) {
 			nbusy = 0;
-			for (bp = &buf[nbuf]; --bp >= buf; ) {
-				if ((bp->b_flags & B_INVAL) == 0 &&
-				    BUF_REFCNT(bp) > 0) {
+			for (bp = &buf[nbuf]; --bp >= buf; )
+				if (isbufbusy(bp))
 					nbusy++;
-				} else if ((bp->b_flags & (B_DELWRI | B_INVAL))
-						== B_DELWRI) {
-					/* bawrite(bp);*/
-					nbusy++;
-				}
-			}
 			if (nbusy == 0) {
 				if (first_buf_printf)
 					printf("All buffers synced.");
@@ -343,8 +346,7 @@ boot(int howto)
 		 */
 		nbusy = 0;
 		for (bp = &buf[nbuf]; --bp >= buf; ) {
-			if (((bp->b_flags&B_INVAL) == 0 && BUF_REFCNT(bp)) ||
-			    ((bp->b_flags & (B_DELWRI|B_INVAL)) == B_DELWRI)) {
+			if (isbufbusy(bp)) {
 #if 0
 /* XXX: This is bogus.  We should probably have a BO_REMOTE flag instead */
 				if (bp->b_dev == NULL) {