[PATCH 2/4] LU-7368 e2fsck: skip quota update when interrupted

[Andreas Dilger <andreas.dilger@intel.com>]

There is a bug in how e2fsck handles being interrupted by CTRL-C.
If CTRL-C is pressed to kill e2fsck rather than e.g. kill -9, then
the interrupt handler sets E2F_FLAG_CANCEL in the context but doesn't
actually kill the process.  Instead, e2fsck_pass1() checks this flag
before processing the next inode.

If a filesystem is running in fix mode (e2fsck -fy) is interrupted,
and the quota feature is enabled, then the quota file will still be
written to disk even though the inode scan was not complete and the
quota information is totally inaccurate.  Even worse, if the Pass 1
inode and block scan was not finished, then the in-memory block
bitmaps (which are used for block allocation during e2fsck) are also
invalid, so any blocks allocated to the quota files may corrupt other
files if those blocks were actually used.

  e2fsck 1.42.13.wc3 (28-Aug-2015)
  Pass 1: Checking inodes, blocks, and sizes
  ^C[QUOTA WARNING] Usage inconsistent for ID 0:
      actual (6455296, 168) != expected (8568832, 231)
  [QUOTA WARNING] Usage inconsistent for ID 695:
      actual (614932320256, 63981) != expected (2102405386240, 176432)
  Update quota info for quota type 0? yes

  [QUOTA WARNING] Usage inconsistent for ID 0:
      actual (6455296, 168) != expected (8568832, 231)
  [QUOTA WARNING] Usage inconsistent for ID 538:
      actual (614932320256, 63981) != expected (2102405386240, 176432)
  Update quota info for quota type 1? yes

  myth-OST0001: e2fsck canceled.
  myth-OST0001: ***** FILE SYSTEM WAS MODIFIED *****

There may be a desire to flush out modified inodes and such that have
been repaired, so that restarting an interrupted e2fsck will make
progress, but the quota file update is plain wrong unless at least
pass1 has finished, and the journal recreation is also dangerous if
the block bitmaps have not been fully updated.

Signed-off-by: Andreas Dilger <andreas.dilger@intel.com>
---
 e2fsck/e2fsck.c |    2 --
 e2fsck/e2fsck.h |    4 ++--
 e2fsck/pass1.c  |    4 +++-
 e2fsck/pass2.c  |   10 +++++-----
 e2fsck/unix.c   |   18 ++++++++++--------
 5 files changed, 20 insertions(+), 18 deletions(-)

diff --git a/e2fsck/e2fsck.c b/e2fsck/e2fsck.c
index 0ec1540..2002dc0 100644
--- a/e2fsck/e2fsck.c
+++ b/e2fsck/e2fsck.c
@@ -203,8 +203,6 @@ static pass_t e2fsck_passes[] = {
 	e2fsck_pass1, e2fsck_pass2, e2fsck_pass3, e2fsck_pass4,
 	e2fsck_pass5, 0 };
 
-#define E2F_FLAG_RUN_RETURN	(E2F_FLAG_SIGNAL_MASK|E2F_FLAG_RESTART)
-
 int e2fsck_run(e2fsck_t ctx)
 {
 	int	i;
diff --git a/e2fsck/e2fsck.h b/e2fsck/e2fsck.h
index f904026..810030e 100644
--- a/e2fsck/e2fsck.h
+++ b/e2fsck/e2fsck.h
@@ -173,10 +173,10 @@ struct resource_track {
  */
 #define E2F_FLAG_ABORT		0x0001 /* Abort signaled */
 #define E2F_FLAG_CANCEL		0x0002 /* Cancel signaled */
-#define E2F_FLAG_SIGNAL_MASK	0x0003
+#define E2F_FLAG_SIGNAL_MASK	(E2F_FLAG_ABORT | E2F_FLAG_CANCEL)
 #define E2F_FLAG_RESTART	0x0004 /* Restart signaled */
+#define E2F_FLAG_RUN_RETURN	(E2F_FLAG_SIGNAL_MASK | E2F_FLAG_RESTART)
 #define E2F_FLAG_RESTART_LATER	0x0008 /* Restart after all iterations done */
-
 #define E2F_FLAG_SETJMP_OK	0x0010 /* Setjmp valid for abort */
 
 #define E2F_FLAG_PROG_BAR	0x0020 /* Progress bar on screen */
diff --git a/e2fsck/pass1.c b/e2fsck/pass1.c
index 50a8b99..1c2b8fd 100644
--- a/e2fsck/pass1.c
+++ b/e2fsck/pass1.c
@@ -766,7 +766,7 @@ void e2fsck_pass1(e2fsck_t ctx)
 							  inode, inode_size);
 		ehandler_operation(old_op);
 		if (ctx->flags & E2F_FLAG_SIGNAL_MASK)
-			return;
+			goto endit;
 		if (pctx.errcode == EXT2_ET_BAD_BLOCK_IN_INODE_TABLE) {
 			if (!ctx->inode_bb_map)
 				alloc_bb_map(ctx);
@@ -1276,6 +1276,8 @@ endit:
 
 	if ((ctx->flags & E2F_FLAG_SIGNAL_MASK) == 0)
 		print_resource_track(ctx, _("Pass 1"), &rtrack, ctx->fs->io);
+	else
+		ctx->invalid_bitmaps++;
 }
 
 /*
diff --git a/e2fsck/pass2.c b/e2fsck/pass2.c
index 2b7bff4..822eee4 100644
--- a/e2fsck/pass2.c
+++ b/e2fsck/pass2.c
@@ -148,14 +148,14 @@ void e2fsck_pass2(e2fsck_t ctx)
 
 	cd.pctx.errcode = ext2fs_dblist_iterate2(fs->dblist, check_dir_block,
 						 &cd);
-	if (ctx->flags & E2F_FLAG_SIGNAL_MASK || ctx->flags & E2F_FLAG_RESTART)
-		return;
-
 	if (ctx->flags & E2F_FLAG_RESTART_LATER) {
 		ctx->flags |= E2F_FLAG_RESTART;
-		return;
+		ctx->flags &= ~E2F_FLAG_RESTART_LATER;
 	}
 
+	if (ctx->flags & E2F_FLAG_RUN_RETURN)
+		return;
+
 	if (cd.pctx.errcode) {
 		fix_problem(ctx, PR_2_DBLIST_ITERATE, &cd.pctx);
 		ctx->flags |= E2F_FLAG_ABORT;
@@ -739,7 +739,7 @@ static int check_dir_block(ext2_filsys fs,
 	buf = cd->buf;
 	ctx = cd->ctx;
 
-	if (ctx->flags & E2F_FLAG_SIGNAL_MASK || ctx->flags & E2F_FLAG_RESTART)
+	if (ctx->flags & E2F_FLAG_RUN_RETURN)
 		return DIRENT_ABORT;
 
 	if (ctx->progress && (ctx->progress)(ctx, 2, cd->count++, cd->max))
diff --git a/e2fsck/unix.c b/e2fsck/unix.c
index 66debcd..6d87f50 100644
--- a/e2fsck/unix.c
+++ b/e2fsck/unix.c
@@ -1667,8 +1667,15 @@ print_unsupp_features:
 	}
 no_journal:
 
-	if (ctx->qctx) {
+	if (run_result & E2F_FLAG_ABORT) {
+		fatal_error(ctx, _("aborted"));
+	} else if (run_result & E2F_FLAG_CANCEL) {
+		log_out(ctx, _("%s: e2fsck canceled.\n"), ctx->device_name ?
+			ctx->device_name : ctx->filesystem_name);
+		exit_value |= FSCK_CANCELED;
+	} else if (ctx->qctx && !ctx->invalid_bitmaps) {
 		int i, needs_writeout;
+
 		for (i = 0; i < MAXQUOTAS; i++) {
 			if (qtype != -1 && qtype != i)
 				continue;
@@ -1695,18 +1702,13 @@ no_journal:
 		ext2fs_close_free(&fs);
 		goto restart;
 	}
-	if (run_result & E2F_FLAG_ABORT)
-		fatal_error(ctx, _("aborted"));
 
 #ifdef MTRACE
 	mtrace_print("Cleanup");
 #endif
 	was_changed = ext2fs_test_changed(fs);
-	if (run_result & E2F_FLAG_CANCEL) {
-		log_out(ctx, _("%s: e2fsck canceled.\n"), ctx->device_name ?
-			ctx->device_name : ctx->filesystem_name);
-		exit_value |= FSCK_CANCELED;
-	} else if (!(ctx->options & E2F_OPT_READONLY)) {
+	if (!(ctx->flags & E2F_FLAG_RUN_RETURN) &&
+	    !(ctx->options & E2F_OPT_READONLY)) {
 		if (ext2fs_test_valid(fs)) {
 			if (!(sb->s_state & EXT2_VALID_FS))
 				exit_value |= FSCK_NONDESTRUCT;
-- 
1.7.3.4