From: David Rhodus <drhodus@dragonflybsd.org>
Date: Tue, 24 Aug 2004 14:01:57 +0000 (+0000)
Subject: Add a few notes.
X-Git-Tag: v2.0.1~10444
X-Git-Url: https://gitweb.dragonflybsd.org/dragonfly.git/commitdiff_plain/0f1737b390edc0d7072934117d96488880271380

Add a few notes.
---

diff --git a/sys/vfs/ufs/ffs_balloc.c b/sys/vfs/ufs/ffs_balloc.c
index 324977c84e..1eaea679bf 100644
--- a/sys/vfs/ufs/ffs_balloc.c
+++ b/sys/vfs/ufs/ffs_balloc.c
@@ -32,7 +32,7 @@
  *
  *	@(#)ffs_balloc.c	8.8 (Berkeley) 6/16/95
  * $FreeBSD: src/sys/ufs/ffs/ffs_balloc.c,v 1.26.2.1 2002/10/10 19:48:20 dillon Exp $
- * $DragonFly: src/sys/vfs/ufs/ffs_balloc.c,v 1.8 2004/07/18 19:43:48 drhodus Exp $
+ * $DragonFly: src/sys/vfs/ufs/ffs_balloc.c,v 1.9 2004/08/24 14:01:57 drhodus Exp $
  */
 
 #include <sys/param.h>
@@ -97,8 +97,21 @@ ffs_balloc(struct vop_balloc_args *ap)
 	 */
 	nb = lblkno(fs, ip->i_size);
 	if (nb < NDADDR && nb < lbn) {
+		/*
+		 * The filesize prior to this write can fit in direct
+		 * blocks (ex. gragmentation is possibly done)
+		 * we are now extending the file write beyond
+		 * the block which has end of the file prior to this write.
 		osize = blksize(fs, ip, nb);
+		/*
+		 * osize gives disk allocated size in the last block. It is
+		 * either in fragments or a file system block size.
+		 */
 		if (osize < fs->fs_bsize && osize > 0) {
+			/* A few fragments are already allocated, since the
+			 * current extends beyond this block allocated the
+			 * complete block as fragments are on in last block.
+			 */
 			error = ffs_realloccg(ip, nb,
 				ffs_blkpref(ip, nb, (int)nb, &ip->i_db[0]),
 				osize, (int)fs->fs_bsize, cred, &bp);
@@ -108,6 +121,7 @@ ffs_balloc(struct vop_balloc_args *ap)
 				softdep_setup_allocdirect(ip, nb,
 				    dbtofsb(fs, bp->b_blkno), ip->i_db[nb],
 				    fs->fs_bsize, osize, bp);
+			/* adjust the inode size, we just grew */
 			ip->i_size = smalllblktosize(fs, nb + 1);
 			ip->i_db[nb] = dbtofsb(fs, bp->b_blkno);
 			ip->i_flag |= IN_CHANGE | IN_UPDATE;
@@ -115,6 +129,7 @@ ffs_balloc(struct vop_balloc_args *ap)
 				bwrite(bp);
 			else
 				bawrite(bp);
+			/* bp is already released here */
 		}
 	}
 	/*
diff --git a/sys/vfs/ufs/ffs_inode.c b/sys/vfs/ufs/ffs_inode.c
index 8219e0c5e6..339fb697ad 100644
--- a/sys/vfs/ufs/ffs_inode.c
+++ b/sys/vfs/ufs/ffs_inode.c
@@ -32,7 +32,7 @@
  *
  *	@(#)ffs_inode.c	8.13 (Berkeley) 4/21/95
  * $FreeBSD: src/sys/ufs/ffs/ffs_inode.c,v 1.56.2.5 2002/02/05 18:35:03 dillon Exp $
- * $DragonFly: src/sys/vfs/ufs/ffs_inode.c,v 1.11 2004/07/18 19:43:48 drhodus Exp $
+ * $DragonFly: src/sys/vfs/ufs/ffs_inode.c,v 1.12 2004/08/24 14:01:57 drhodus Exp $
  */
 
 #include "opt_quota.h"
@@ -280,6 +280,7 @@ ffs_truncate(struct vnode *vp, off_t length, int flags, struct ucred *cred,
 	lastiblock[DOUBLE] = lastiblock[SINGLE] - NINDIR(fs);
 	lastiblock[TRIPLE] = lastiblock[DOUBLE] - NINDIR(fs) * NINDIR(fs);
 	nblocks = btodb(fs->fs_bsize);
+
 	/*
 	 * Update file and block pointers on disk before we start freeing
 	 * blocks.  If we crash before free'ing blocks below, the blocks
diff --git a/sys/vfs/ufs/ffs_vfsops.c b/sys/vfs/ufs/ffs_vfsops.c
index 98d533292e..2ca7b8c44e 100644
--- a/sys/vfs/ufs/ffs_vfsops.c
+++ b/sys/vfs/ufs/ffs_vfsops.c
@@ -32,7 +32,7 @@
  *
  *	@(#)ffs_vfsops.c	8.31 (Berkeley) 5/20/95
  * $FreeBSD: src/sys/ufs/ffs/ffs_vfsops.c,v 1.117.2.10 2002/06/23 22:34:52 iedowse Exp $
- * $DragonFly: src/sys/vfs/ufs/ffs_vfsops.c,v 1.22 2004/08/19 14:42:46 drhodus Exp $
+ * $DragonFly: src/sys/vfs/ufs/ffs_vfsops.c,v 1.23 2004/08/24 14:01:57 drhodus Exp $
  */
 
 #include "opt_quota.h"
@@ -925,6 +925,7 @@ ffs_flushfiles(struct mount *mp, int flags, struct thread *td)
 		error = vflush(mp, 0, SKIPSYSTEM|flags);
 		if (error)
 			return (error);
+		/* Find out how many quota files  we have open. */
 		for (i = 0; i < MAXQUOTAS; i++) {
 			if (ump->um_quotas[i] == NULLVP)
 				continue;
@@ -1053,6 +1054,9 @@ ffs_sync_scan1(struct mount *mp, struct vnode *vp, void *data)
 	 * call unless there's a good chance that we have work to do.
 	 */
 	ip = VTOI(vp);
+	/* Restart out whole search if this guy is locked
+	 * or is being reclaimed.
+	 */
 	if (vp->v_type == VNON || ((ip->i_flag &
 	     (IN_ACCESS | IN_CHANGE | IN_MODIFIED | IN_UPDATE)) == 0 &&
 	     TAILQ_EMPTY(&vp->v_dirtyblkhd))) {
@@ -1184,6 +1188,7 @@ restart:
 			ip->i_dquot[i] = NODQUOT;
 	}
 #endif
+
 	/*
 	 * Put it onto its hash chain and lock it so that other requests for
 	 * this inode will block if they arrive while we are sleeping waiting
diff --git a/sys/vfs/ufs/ffs_vnops.c b/sys/vfs/ufs/ffs_vnops.c
index 28006a29df..99099cb0da 100644
--- a/sys/vfs/ufs/ffs_vnops.c
+++ b/sys/vfs/ufs/ffs_vnops.c
@@ -32,7 +32,7 @@
  *
  *	@(#)ffs_vnops.c	8.15 (Berkeley) 5/14/95
  * $FreeBSD: src/sys/ufs/ffs/ffs_vnops.c,v 1.64 2000/01/10 12:04:25 phk Exp $
- * $DragonFly: src/sys/vfs/ufs/ffs_vnops.c,v 1.10 2004/08/17 18:57:36 dillon Exp $
+ * $DragonFly: src/sys/vfs/ufs/ffs_vnops.c,v 1.11 2004/08/24 14:01:57 drhodus Exp $
  */
 
 #include <sys/param.h>
@@ -224,7 +224,7 @@ loop:
 	if (wait) {
 		while (vp->v_numoutput) {
 			vp->v_flag |= VBWAIT;
-			(void) tsleep((caddr_t)&vp->v_numoutput, 0, "ffsfsn", 0);
+			(void)tsleep((caddr_t)&vp->v_numoutput, 0, "ffsfsn", 0);
   		}
 
 		/*