fuzzy: add a custom xfs find utility for scrub stress tests

Create a new find(1) like utility that doesn't crash on directory tree
changes (like find does due to bugs in its loop detector) and actually
implements the custom xfs attribute predicates that we need for scrub
stress tests.  This program will be needed for a future patch where we
add stress tests for scrub and repair of file metadata.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Zorro Lang <zlang@redhat.com>
Signed-off-by: Zorro Lang <zlang@kernel.org>

2 files changed, 300 insertions, 0 deletions

diff --git a/src/Makefile b/src/Makefile
index f270015c..a574f7bd 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -83,6 +83,16 @@ ifeq ($(HAVE_LIBCAP), true)
 LLDLIBS += -lcap
 endif
 
+ifeq ($(HAVE_SEEK_DATA), yes)
+ ifeq ($(HAVE_NFTW), yes)
+  ifeq ($(HAVE_BMV_OF_SHARED), yes)
+   ifeq ($(HAVE_RLIMIT_NOFILE), yes)
+     TARGETS += xfsfind
+   endif
+  endif
+ endif
+endif
+
 CFILES = $(TARGETS:=.c)
 LDIRT = $(TARGETS) fssum
 
diff --git a/src/xfsfind.c b/src/xfsfind.c
new file mode 100644
index 00000000..6b0a93e7
--- /dev/null
+++ b/src/xfsfind.c
@@ -0,0 +1,290 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * find(1) but with special predicates for finding XFS attributes.
+ * Copyright (C) 2022 Oracle.
+ */
+#include <sys/time.h>
+#include <sys/resource.h>
+#include <sys/types.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <ftw.h>
+#include <linux/fs.h>
+#include <xfs/xfs.h>
+
+#include "global.h"
+
+static int want_anyfile;
+static int want_datafile;
+static int want_attrfile;
+static int want_dir;
+static int want_regfile;
+static int want_sharedfile;
+static int report_errors = 1;
+
+static int
+check_datafile(
+	const char		*path,
+	int			fd)
+{
+	off_t			off;
+
+	off = lseek(fd, 0, SEEK_DATA);
+	if (off >= 0)
+		return 1;
+
+	if (errno == ENXIO)
+		return 0;
+
+	if (report_errors)
+		perror(path);
+
+	return -1;
+}
+
+static int
+check_attrfile(
+	const char		*path,
+	int			fd)
+{
+	struct fsxattr		fsx;
+	int			ret;
+
+	ret = ioctl(fd, XFS_IOC_FSGETXATTR, &fsx);
+	if (ret) {
+		if (report_errors)
+			perror(path);
+		return -1;
+	}
+
+	if (want_attrfile && (fsx.fsx_xflags & XFS_XFLAG_HASATTR))
+		return 1;
+	return 0;
+}
+
+#define BMAP_NR			33
+static struct getbmapx		bmaps[BMAP_NR];
+
+static int
+check_sharedfile(
+	const char		*path,
+	int			fd)
+{
+	struct getbmapx		*key = &bmaps[0];
+	unsigned int		i;
+	int			ret;
+
+	memset(key, 0, sizeof(struct getbmapx));
+	key->bmv_length = ULLONG_MAX;
+	/* no holes and don't flush dirty pages */
+	key->bmv_iflags = BMV_IF_DELALLOC | BMV_IF_NO_HOLES;
+	key->bmv_count = BMAP_NR;
+
+	while ((ret = ioctl(fd, XFS_IOC_GETBMAPX, bmaps)) == 0) {
+		struct getbmapx	*p = &bmaps[1];
+		xfs_off_t	new_off;
+
+		for (i = 0; i < key->bmv_entries; i++, p++) {
+			if (p->bmv_oflags & BMV_OF_SHARED)
+				return 1;
+		}
+
+		if (key->bmv_entries == 0)
+			break;
+		p = key + key->bmv_entries;
+		if (p->bmv_oflags & BMV_OF_LAST)
+			return 0;
+
+		new_off = p->bmv_offset + p->bmv_length;
+		key->bmv_length -= new_off - key->bmv_offset;
+		key->bmv_offset = new_off;
+	}
+	if (ret < 0) {
+		if (report_errors)
+			perror(path);
+		return -1;
+	}
+
+	return 0;
+}
+
+static void
+print_help(
+	const char		*name)
+{
+	printf("Usage: %s [OPTIONS] path\n", name);
+	printf("\n");
+	printf("Print all file paths matching any of the given predicates.\n");
+	printf("\n");
+	printf("-a	Match files with xattrs.\n");
+	printf("-b	Match files with data blocks.\n");
+	printf("-d	Match directories.\n");
+	printf("-q	Ignore errors while walking directory tree.\n");
+	printf("-r	Match regular files.\n");
+	printf("-s	Match files with shared blocks.\n");
+	printf("\n");
+	printf("If no matching options are given, match all files found.\n");
+}
+
+static int
+visit(
+	const char		*path,
+	const struct stat	*sb,
+	int			typeflag,
+	struct FTW		*ftwbuf)
+{
+	int			printme = 1;
+	int			fd = -1;
+	int			retval = FTW_CONTINUE;
+
+	if (want_anyfile)
+		goto out;
+	if (want_regfile && typeflag == FTW_F)
+		goto out;
+	if (want_dir && typeflag == FTW_D)
+		goto out;
+
+	/*
+	 * We can only open directories and files; screen out everything else.
+	 * Note that nftw lies and reports FTW_F for device files, so check the
+	 * statbuf mode too.
+	 */
+	if (typeflag != FTW_F && typeflag != FTW_D) {
+		printme = 0;
+		goto out;
+	}
+
+	if (!S_ISREG(sb->st_mode) && !S_ISDIR(sb->st_mode)) {
+		printme = 0;
+		goto out;
+	}
+
+	fd = open(path, O_RDONLY);
+	if (fd < 0) {
+		if (report_errors) {
+			perror(path);
+			return FTW_STOP;
+		}
+
+		return FTW_CONTINUE;
+	}
+
+	if (want_datafile && typeflag == FTW_F) {
+		int ret = check_datafile(path, fd);
+		if (ret < 0 && report_errors) {
+			printme = 0;
+			retval = FTW_STOP;
+			goto out_fd;
+		}
+
+		if (ret == 1)
+			goto out_fd;
+	}
+
+	if (want_attrfile) {
+		int ret = check_attrfile(path, fd);
+		if (ret < 0 && report_errors) {
+			printme = 0;
+			retval = FTW_STOP;
+			goto out_fd;
+		}
+
+		if (ret == 1)
+			goto out_fd;
+	}
+
+	if (want_sharedfile) {
+		int ret = check_sharedfile(path, fd);
+		if (ret < 0 && report_errors) {
+			printme = 0;
+			retval = FTW_STOP;
+			goto out_fd;
+		}
+
+		if (ret == 1)
+			goto out_fd;
+	}
+
+	printme = 0;
+out_fd:
+	close(fd);
+out:
+	if (printme)
+		printf("%s\n", path);
+	return retval;
+}
+
+static void
+handle_sigabrt(
+	int		signal,
+	siginfo_t	*info,
+	void		*ucontext)
+{
+	fprintf(stderr, "Signal %u, exiting.\n", signal);
+	exit(2);
+}
+
+int
+main(
+	int			argc,
+	char			*argv[])
+{
+	struct rlimit		rlimit;
+	struct sigaction	abrt = {
+		.sa_sigaction	= handle_sigabrt,
+		.sa_flags	= SA_SIGINFO,
+	};
+	int			c;
+	int			ret;
+
+	while ((c = getopt(argc, argv, "abdqrs")) >= 0) {
+		switch (c) {
+		case 'a':	want_attrfile = 1;   break;
+		case 'b':	want_datafile = 1;   break;
+		case 'd':	want_dir = 1;        break;
+		case 'q':	report_errors = 0;   break;
+		case 'r':	want_regfile = 1;    break;
+		case 's':	want_sharedfile = 1; break;
+		default:
+			print_help(argv[0]);
+			return 1;
+		}
+	}
+
+	ret = getrlimit(RLIMIT_NOFILE, &rlimit);
+	if (ret) {
+		perror("RLIMIT_NOFILE");
+		return 1;
+	}
+
+	if (!want_attrfile && !want_datafile && !want_dir && !want_regfile &&
+	    !want_sharedfile)
+		want_anyfile = 1;
+
+	/*
+	 * nftw is known to abort() if a directory it is walking disappears out
+	 * from under it.  Handle this with grace if the caller wants us to run
+	 * quietly.
+	 */
+	if (!report_errors) {
+		ret = sigaction(SIGABRT, &abrt, NULL);
+		if (ret) {
+			perror("SIGABRT handler");
+			return 1;
+		}
+	}
+
+	for (c = optind; c < argc; c++) {
+		ret = nftw(argv[c], visit, rlimit.rlim_cur - 5,
+				FTW_ACTIONRETVAL | FTW_CHDIR | FTW_MOUNT |
+				FTW_PHYS);
+		if (ret && report_errors) {
+			perror(argv[c]);
+			break;
+		}
+	}
+
+	if (ret)
+		return 1;
+	return 0;
+}