[PATCH 3/4] e2fsck: Do not discard when in read only mode

[Lukas Czerner <lczerner@redhat.com>]

When argument '-n' was specified and should run in read-only mode, we
should not attempt to discard anything. In order to do that we have to
check for E2F_OPT_NO flag and clear E2F_OPT_DISCARD flag if E2F_OPT_NO
is set.

This commit fixes the problem when we would mark inode tables as zeroed
(EXT2_BG_INODE_ZEROED) even when e2fsck is running in read-only mode. We
also move the check for E2F_OPT_NO so we can clear E2F_OPT_DISCARD as
early as possible.

Signed-off-by: Lukas Czerner <lczerner@redhat.com>
---
 e2fsck/pass5.c |    5 ++---
 e2fsck/unix.c  |    5 +++++
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/e2fsck/pass5.c b/e2fsck/pass5.c
index 37bbac2..741e6dd 100644
--- a/e2fsck/pass5.c
+++ b/e2fsck/pass5.c
@@ -88,8 +88,7 @@ static void e2fsck_discard_blocks(e2fsck_t ctx, blk64_t start,
 	if (ext2fs_test_changed(fs))
 		ctx->options &= ~E2F_OPT_DISCARD;
 
-	if (!(ctx->options & E2F_OPT_NO) &&
-	    (ctx->options & E2F_OPT_DISCARD) &&
+	if ((ctx->options & E2F_OPT_DISCARD) &&
 	    (io_channel_discard(fs->io, start, count)))
 		ctx->options &= ~E2F_OPT_DISCARD;
 }
@@ -117,7 +116,7 @@ static void e2fsck_discard_inodes(e2fsck_t ctx, int group,
 		ctx->options &= ~E2F_OPT_DISCARD;
 	}
 
-	if ((ctx->options & E2F_OPT_NO) || !(ctx->options & E2F_OPT_DISCARD))
+	if (!(ctx->options & E2F_OPT_DISCARD))
 		return;
 
 	/*
diff --git a/e2fsck/unix.c b/e2fsck/unix.c
index 6f97b0f..b31a1e3 100644
--- a/e2fsck/unix.c
+++ b/e2fsck/unix.c
@@ -903,6 +903,11 @@ static errcode_t PRS(int argc, char *argv[], e2fsck_t *ret_ctx)
 	profile_set_syntax_err_cb(syntax_err_report);
 	profile_init(config_fn, &ctx->profile);
 
+	/* Turn off discard in read-only mode */
+	if ((ctx->options & E2F_OPT_NO) &&
+	    (ctx->options & E2F_OPT_DISCARD))
+		ctx->options &= ~E2F_OPT_DISCARD;
+
 	if (flush) {
 		fd = open(ctx->filesystem_name, O_RDONLY, 0);
 		if (fd < 0) {
-- 
1.7.4.4