Additions to run checks on live filesystems. This change will not

affect current systems until fsck is modified to use these new
facilities. To try out this change, set the fsck passno to zero
in /etc/fstab to cause the filesystem to be mounted without running
fsck, then run `fsck_ffs -p -B <filesystem>' after the system has
been brought up multiuser to run a background cleanup on <filesystem>.
Note that the <filesystem> in question must have soft updates enabled.

1 files changed, 55 insertions, 7 deletions

diff --git a/sbin/fsck_ffs/setup.c b/sbin/fsck_ffs/setup.c
index 24000be..bd928fb 100644
--- a/sbin/fsck_ffs/setup.c
+++ b/sbin/fsck_ffs/setup.c
@@ -86,25 +86,73 @@ setup(dev)
 	skipclean = fflag ? 0 : preen;
 	if (stat(dev, &statb) < 0) {
 		printf("Can't stat %s: %s\n", dev, strerror(errno));
+		if (bkgrdflag) {
+			unlink(snapname);
+			bkgrdflag = 0;
+		}
 		return (0);
 	}
 	if ((statb.st_mode & S_IFMT) != S_IFCHR &&
 	    (statb.st_mode & S_IFMT) != S_IFBLK) {
-		if ((statb.st_flags & SF_SNAPSHOT) != 0) {
+		if (bkgrdflag != 0 && (statb.st_flags & SF_SNAPSHOT) == 0) {
+			unlink(snapname);
+			printf("background fsck lacks a snapshot\n");
+			exit(EEXIT);
+		}
+		if ((statb.st_flags & SF_SNAPSHOT) != 0 && cvtlevel == 0) {
 			cursnapshot = statb.st_ino;
 		} else {
-			pfatal("%s is not a disk device", dev);
-			if (reply("CONTINUE") == 0)
-				return (0);
+			if (cvtlevel == 0 ||
+			    (statb.st_flags & SF_SNAPSHOT) == 0) {
+				if (preen && bkgrdflag) {
+					unlink(snapname);
+					bkgrdflag = 0;
+				}
+				pfatal("%s is not a disk device", dev);
+				if (reply("CONTINUE") == 0) {
+					if (bkgrdflag) {
+						unlink(snapname);
+						bkgrdflag = 0;
+					}
+					return (0);
+				}
+			} else {
+				if (bkgrdflag) {
+					unlink(snapname);
+					bkgrdflag = 0;
+				}
+				pfatal("cannot convert a snapshot");
+				exit(EEXIT);
+			}
 		}
 	}
 	if ((fsreadfd = open(dev, O_RDONLY)) < 0) {
+		if (bkgrdflag) {
+			unlink(snapname);
+			bkgrdflag = 0;
+		}
 		printf("Can't open %s: %s\n", dev, strerror(errno));
 		return (0);
 	}
+	if (bkgrdflag) {
+		unlink(snapname);
+		size = MIBSIZE;
+		if (sysctlnametomib("vfs.ffs.adjrefcnt", adjrefcnt, &size) < 0||
+		    sysctlnametomib("vfs.ffs.adjblkcnt", adjblkcnt, &size) < 0||
+		    sysctlnametomib("vfs.ffs.freefiles", freefiles, &size) < 0||
+		    sysctlnametomib("vfs.ffs.freedirs", freedirs, &size) < 0 ||
+		    sysctlnametomib("vfs.ffs.freeblks", freeblks, &size) < 0) {
+			pfatal("kernel lacks background fsck support\n");
+			exit(EEXIT);
+		}
+		cmd.version = FFS_CMD_VERSION;
+		cmd.handle = fsreadfd;
+		fswritefd = -1;
+	}
 	if (preen == 0)
 		printf("** %s", dev);
-	if (nflag || (fswritefd = open(dev, O_WRONLY)) < 0) {
+	if (bkgrdflag == 0 &&
+	    (nflag || (fswritefd = open(dev, O_WRONLY)) < 0)) {
 		fswritefd = -1;
 		if (preen)
 			pfatal("NO WRITE ACCESS");
@@ -178,7 +226,7 @@ setup(dev)
 	}
 	if (sblock.fs_interleave < 1 ||
 	    sblock.fs_interleave > sblock.fs_nsect) {
-		pwarn("IMPOSSIBLE INTERLEAVE=%d IN SUPERBLOCK",
+		pfatal("IMPOSSIBLE INTERLEAVE=%d IN SUPERBLOCK",
 			sblock.fs_interleave);
 		sblock.fs_interleave = 1;
 		if (preen)
@@ -190,7 +238,7 @@ setup(dev)
 	}
 	if (sblock.fs_npsect < sblock.fs_nsect ||
 	    sblock.fs_npsect > sblock.fs_nsect*2) {
-		pwarn("IMPOSSIBLE NPSECT=%d IN SUPERBLOCK",
+		pfatal("IMPOSSIBLE NPSECT=%d IN SUPERBLOCK",
 			sblock.fs_npsect);
 		sblock.fs_npsect = sblock.fs_nsect;
 		if (preen)