Date: Fri, 3 Mar 2000 13:07:39 -0500 (EST) From: Luoqi Chen <luoqi@watermarkgroup.com> To: current@FreeBSD.ORG, sheldonh@uunet.co.za Subject: Re: tunefs -p doesn't work for read-write mounts Message-ID: <200003031807.NAA21331@lor.watermarkgroup.com>
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> Hi folks,
>
> Shouldn't I be able to show the current tuneables for a given filesystem?
>
> # tunefs -p /usr
> tunefs: cannot work on read-write mounted file system
>
> This is on a recent CURRENT.
>
> Ciao,
> Sheldon.
>
You were supposed to use a raw device for a mounted fs, but that no longer
works after the elimination of block device. I have a quick fix for this
problem: open the device read-only to read the superblock and later re-open
it read-write before writing back.
-lq
Index: tunefs.c
===================================================================
RCS file: /home/ncvs/src/sbin/tunefs/tunefs.c,v
retrieving revision 1.11
diff -u -r1.11 tunefs.c
--- tunefs.c 2000/01/30 05:24:55 1.11
+++ tunefs.c 2000/03/03 16:04:04
@@ -75,9 +75,10 @@
int fi;
long dev_bsize = 1;
-void bwrite(daddr_t, char *, int);
-int bread(daddr_t, char *, int);
-void getsb(struct fs *, char *);
+void bwrite __P((daddr_t, char *, int));
+int bread __P((daddr_t, char *, int));
+void getsb __P((struct fs *, char *));
+void putsb __P((struct fs *, char *, int));
void usage __P((void));
void printfs __P((void));
@@ -103,9 +104,6 @@
if (fs) {
if (statfs(special, &stfs) == 0 &&
strcmp(special, stfs.f_mntonname) == 0) {
- if ((stfs.f_flags & MNT_RDONLY) == 0) {
- errx(1, "cannot work on read-write mounted file system");
- }
active = 1;
}
special = fs->fs_spec;
@@ -251,12 +249,7 @@
}
if (argc != 1)
usage();
- bwrite((daddr_t)SBOFF / dev_bsize, (char *)&sblock, SBSIZE);
- if (Aflag)
- for (i = 0; i < sblock.fs_ncg; i++)
- bwrite(fsbtodb(&sblock, cgsblock(&sblock, i)),
- (char *)&sblock, SBSIZE);
- close(fi);
+ putsb(&sblock, special, Aflag);
if (active) {
bzero(&args, sizeof(args));
if (mount("ufs", fs->fs_file,
@@ -283,7 +276,7 @@
char *file;
{
- fi = open(file, 2);
+ fi = open(file, 0);
if (fi < 0)
err(3, "cannot open %s", file);
if (bread((daddr_t)SBOFF, (char *)fs, SBSIZE))
@@ -291,6 +284,30 @@
if (fs->fs_magic != FS_MAGIC)
err(5, "%s: bad magic number", file);
dev_bsize = fs->fs_fsize / fsbtodb(fs, 1);
+}
+
+void
+putsb(fs, file, all)
+ register struct fs *fs;
+ char *file;
+ int all;
+{
+ int i;
+
+ /*
+ * Re-open the device read-write. Use the read-only file
+ * descriptor as an interlock to prevent the device from
+ * being mounted while we are switching mode.
+ */
+ i = fi; fi = open(file, 2); close(i);
+ if (fi < 0)
+ err(3, "cannot open %s", file);
+ bwrite((daddr_t)SBOFF / dev_bsize, (char *)fs, SBSIZE);
+ if (all)
+ for (i = 0; i < fs->fs_ncg; i++)
+ bwrite(fsbtodb(fs, cgsblock(fs, i)),
+ (char *)fs, SBSIZE);
+ close(fi);
}
void
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