e2fsck: Add the ability to force a problem to not be fixed

The boolean options "force_no" in the problems stanza of e2fsck.conf
allows a particular problem code be treated as if the user will answer
"no" to the question of whether a particular problem should be fixed
--- even if e2fsck is run with the -y option.

As an example use case, suppose a distribution had widely deployed a
version of the kernel where under some circumstances, the EOFBLOCKS_FL
flag would be left set even though it should not be left set, and a
customer had a workload which exercised the fencepost error all the
time, resulting in many large number of inodes that had EOFBLOCKS_FL
set erroneously.  Enough, in fact, the e2fsck runs were taking too
long.  (There was such a bug in the kernel, which was fixed by commit
58590b06d in 2.6.36).

Leaving EOFBLOCKS_FL set when it should not be isn't a huge deal, and
is certainly than having high availability timeout alerts going off
left and right.  So in this case, the best fix might be to put the
following in /etc/e2fsck.conf:

[problems]
0x010060 = {			# PR_1_EOFBLOCKS_FL_SET
	 force_no = true
	 no_ok = true
	 no_nomsg = true
}

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

3 files changed, 21 insertions, 4 deletions

diff --git a/e2fsck/e2fsck.conf.5.in b/e2fsck/e2fsck.conf.5.in
index 4c90293e..e09cd6d7 100644
--- a/e2fsck/e2fsck.conf.5.in
+++ b/e2fsck/e2fsck.conf.5.in
@@ -190,11 +190,22 @@ is running in preen mode.
 .I no_nomsg
 This boolean relation overrides the default behavior controlling 
 whether or not the description for this filesystem problem should
-be suppressed when
+be suppressed when a problem forced not to be fixed, either because
 .B e2fsck
 is run with the
 .B -n
-option.
+option or because the
+.I force_no
+flag has been set for the problem.
+.TP
+.I force_no
+This boolean option, if set to true, forces a problem to never be fixed.
+That is, it will be as if the user problem responds 'no' to the question
+of 'should this problem be fixed?'.  The
+.I force_no
+option even overrides the
+.B -y
+option given on the command-line (just for the specific problem, of course).
 .SH THE [scratch_files] STANZA
 The following relations are defined in the 
 .I [scratch_files]
diff --git a/e2fsck/problem.c b/e2fsck/problem.c
index 8032fdae..8f0b211a 100644
--- a/e2fsck/problem.c
+++ b/e2fsck/problem.c
@@ -1773,6 +1773,7 @@ int fix_problem(e2fsck_t ctx, problem_t code, struct problem_context *pctx)
 		reconfigure_bool(ctx, ptr, key, PR_NOCOLLATE, "no_collate");
 		reconfigure_bool(ctx, ptr, key, PR_NO_NOMSG, "no_nomsg");
 		reconfigure_bool(ctx, ptr, key, PR_PREEN_NOHDR, "preen_noheader");
+		reconfigure_bool(ctx, ptr, key, PR_FORCE_NO, "force_no");
 
 		ptr->flags |= PR_CONFIG;
 	}
@@ -1803,7 +1804,7 @@ int fix_problem(e2fsck_t ctx, problem_t code, struct problem_context *pctx)
 	    (ctx->options & E2F_OPT_PREEN))
 		suppress++;
 	if ((ptr->flags & PR_NO_NOMSG) &&
-	    (ctx->options & E2F_OPT_NO))
+	    ((ctx->options & E2F_OPT_NO) || (ptr->flags & PR_FORCE_NO)))
 		suppress++;
 	if (!suppress) {
 		message = ptr->e2p_description;
@@ -1827,7 +1828,11 @@ int fix_problem(e2fsck_t ctx, problem_t code, struct problem_context *pctx)
 		else
 			answer = def_yn;
 	} else {
-		if (ctx->options & E2F_OPT_PREEN) {
+		if (ptr->flags & PR_FORCE_NO) {
+			answer = 0;
+			if (!suppress)
+				print_answer = 1;
+		} else if (ctx->options & E2F_OPT_PREEN) {
 			answer = def_yn;
 			if (!(ptr->flags & PR_PREEN_NOMSG))
 				print_answer = 1;
diff --git a/e2fsck/problemP.h b/e2fsck/problemP.h
index 61611898..a2ed35e5 100644
--- a/e2fsck/problemP.h
+++ b/e2fsck/problemP.h
@@ -41,3 +41,4 @@ struct latch_descr {
 #define PR_PREEN_NOHDR	0x040000 /* Don't print the preen header */
 #define PR_CONFIG	0x080000 /* This problem has been customized
 				    from the config file */
+#define PR_FORCE_NO	0x100000 /* Force the answer to be no */