3 files changed, 20 insertions, 3 deletions

diff --git a/bftw.c b/bftw.c
index e64a93c..edca612 100644
--- a/bftw.c
+++ b/bftw.c
@@ -656,10 +656,12 @@ static void bftw_init_buffers(struct bftw_state *state, const struct dirent *de)
 	bool detect_cycles = (state->flags & BFTW_DETECT_CYCLES)
 		&& state->status == BFTW_CHILD;
 
+	bool mount = state->flags & BFTW_MOUNT;
+
 	if ((state->flags & BFTW_STAT)
 	    || ftwbuf->typeflag == BFTW_UNKNOWN
 	    || (ftwbuf->typeflag == BFTW_LNK && follow)
-	    || (ftwbuf->typeflag == BFTW_DIR && detect_cycles)) {
+	    || (ftwbuf->typeflag == BFTW_DIR && (detect_cycles || mount))) {
 		int ret = ftwbuf_stat(ftwbuf, &state->statbuf, ftwbuf->at_flags);
 		if (ret != 0 && follow && errno == ENOENT) {
 			// Could be a broken symlink, retry without following
@@ -719,7 +721,7 @@ static struct dircache_entry *bftw_add(struct bftw_state *state, const char *nam
 		return NULL;
 	}
 
-	if (state->flags & BFTW_DETECT_CYCLES) {
+	if (state->flags & (BFTW_DETECT_CYCLES | BFTW_MOUNT)) {
 		const struct stat *statbuf = state->ftwbuf.statbuf;
 		if (statbuf) {
 			entry->dev = statbuf->st_dev;
@@ -910,6 +912,13 @@ int bftw(const char *path, bftw_fn *fn, int nopenfd, enum bftw_flags flags, void
 			}
 
 			if (state.ftwbuf.typeflag == BFTW_DIR) {
+				const struct stat *statbuf = state.ftwbuf.statbuf;
+				if ((flags & BFTW_MOUNT)
+				    && statbuf
+				    && statbuf->st_dev != state.current->dev) {
+					continue;
+				}
+
 				if (bftw_push(&state, de->d_name) != 0) {
 					goto fail;
 				}
diff --git a/bftw.h b/bftw.h
index 790d422..0b692b0 100644
--- a/bftw.h
+++ b/bftw.h
@@ -120,6 +120,8 @@ enum bftw_flags {
 	BFTW_FOLLOW         = BFTW_FOLLOW_ROOT | BFTW_FOLLOW_NONROOT,
 	/** Detect directory cycles. */
 	BFTW_DETECT_CYCLES  = 1 << 5,
+	/** Stay on the same filesystem. */
+	BFTW_MOUNT          = 1 << 6,
 };
 
 /**
diff --git a/parse.c b/parse.c
index 6177e76..74b51cb 100644
--- a/parse.c
+++ b/parse.c
@@ -679,6 +679,9 @@ static struct expr *parse_literal(struct parser_state *state) {
 			return parse_depth(state, arg, &state->cmdline->maxdepth);
 		} else if (strcmp(arg, "-mmin") == 0) {
 			return parse_acmtime(state, arg, MTIME, MINUTES);
+		} else if (strcmp(arg, "-mount") == 0) {
+			state->cmdline->flags |= BFTW_MOUNT;
+			return new_option(state, arg);
 		} else if (strcmp(arg, "-mtime") == 0) {
 			return parse_acmtime(state, arg, MTIME, DAYS);
 		}
@@ -762,7 +765,10 @@ static struct expr *parse_literal(struct parser_state *state) {
 		break;
 
 	case 'x':
-		if (strcmp(arg, "-xtype") == 0) {
+		if (strcmp(arg, "-xdev") == 0) {
+			state->cmdline->flags |= BFTW_MOUNT;
+			return new_option(state, arg);
+		} else if (strcmp(arg, "-xtype") == 0) {
 			return parse_type(state, arg, eval_xtype);
 		}
 		break;