diff mbox series

[v2,13/14] samples: Add fs error monitoring example

Message ID 20210615235556.970928-14-krisman@collabora.com (mailing list archive)
State New
Headers show
Series File system wide monitoring | expand

Commit Message

Gabriel Krisman Bertazi June 15, 2021, 11:55 p.m. UTC
Introduce an example of a FAN_FS_ERROR fanotify user to track filesystem
errors.

Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>

---
Changes since v1:
  - minor fixes
---
 samples/Kconfig               |  9 ++++
 samples/Makefile              |  1 +
 samples/fanotify/Makefile     |  3 ++
 samples/fanotify/fs-monitor.c | 95 +++++++++++++++++++++++++++++++++++
 4 files changed, 108 insertions(+)
 create mode 100644 samples/fanotify/Makefile
 create mode 100644 samples/fanotify/fs-monitor.c

Comments

kernel test robot June 16, 2021, 1:04 p.m. UTC | #1
Hi Gabriel,

I love your patch! Yet something to improve:

[auto build test ERROR on ext3/fsnotify]
[also build test ERROR on linus/master v5.13-rc6 next-20210615]
[cannot apply to ext4/dev]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Gabriel-Krisman-Bertazi/File-system-wide-monitoring/20210616-155248
base:   https://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs.git fsnotify
config: m68k-allmodconfig (attached as .config)
compiler: m68k-linux-gcc (GCC) 9.3.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/0day-ci/linux/commit/cefa2ac082849b4b7bb22317625cf3371a52faaf
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Gabriel-Krisman-Bertazi/File-system-wide-monitoring/20210616-155248
        git checkout cefa2ac082849b4b7bb22317625cf3371a52faaf
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=m68k 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

>> samples/fanotify/fs-monitor.c:7:10: fatal error: errno.h: No such file or directory
       7 | #include <errno.h>
         |          ^~~~~~~~~
   compilation terminated.


vim +7 samples/fanotify/fs-monitor.c

   > 7	#include <errno.h>
     8	#include <err.h>
     9	#include <stdlib.h>
    10	#include <stdio.h>
    11	#include <fcntl.h>
    12	#include <sys/fanotify.h>
    13	#include <sys/types.h>
    14	#include <unistd.h>
    15	#include <sys/stat.h>
    16	#include <sys/types.h>
    17	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
diff mbox series

Patch

diff --git a/samples/Kconfig b/samples/Kconfig
index b5a1a7aa7e23..f2f9c939035f 100644
--- a/samples/Kconfig
+++ b/samples/Kconfig
@@ -120,6 +120,15 @@  config SAMPLE_CONNECTOR
 	  with it.
 	  See also Documentation/driver-api/connector.rst
 
+config SAMPLE_FANOTIFY_ERROR
+	bool "Build fanotify error monitoring sample"
+	depends on FANOTIFY
+	help
+	  When enabled, this builds an example code that uses the
+	  FAN_FS_ERROR fanotify mechanism to monitor filesystem
+	  errors.
+	  See also Documentation/admin-guide/filesystem-monitoring.rst.
+
 config SAMPLE_HIDRAW
 	bool "hidraw sample"
 	depends on CC_CAN_LINK && HEADERS_INSTALL
diff --git a/samples/Makefile b/samples/Makefile
index 087e0988ccc5..931a81847c48 100644
--- a/samples/Makefile
+++ b/samples/Makefile
@@ -5,6 +5,7 @@  subdir-$(CONFIG_SAMPLE_AUXDISPLAY)	+= auxdisplay
 subdir-$(CONFIG_SAMPLE_ANDROID_BINDERFS) += binderfs
 obj-$(CONFIG_SAMPLE_CONFIGFS)		+= configfs/
 obj-$(CONFIG_SAMPLE_CONNECTOR)		+= connector/
+obj-$(CONFIG_SAMPLE_FANOTIFY_ERROR)	+= fanotify/
 subdir-$(CONFIG_SAMPLE_HIDRAW)		+= hidraw
 obj-$(CONFIG_SAMPLE_HW_BREAKPOINT)	+= hw_breakpoint/
 obj-$(CONFIG_SAMPLE_KDB)		+= kdb/
diff --git a/samples/fanotify/Makefile b/samples/fanotify/Makefile
new file mode 100644
index 000000000000..b3d5cc826e6f
--- /dev/null
+++ b/samples/fanotify/Makefile
@@ -0,0 +1,3 @@ 
+userprogs-always-y += fs-monitor
+
+userccflags += -I usr/include
diff --git a/samples/fanotify/fs-monitor.c b/samples/fanotify/fs-monitor.c
new file mode 100644
index 000000000000..cb23a2592337
--- /dev/null
+++ b/samples/fanotify/fs-monitor.c
@@ -0,0 +1,95 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright 2021, Collabora Ltd.
+ */
+
+#define _GNU_SOURCE
+#include <errno.h>
+#include <err.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <fcntl.h>
+#include <sys/fanotify.h>
+#include <sys/types.h>
+#include <unistd.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+
+#ifndef FAN_FS_ERROR
+#define FAN_FS_ERROR		0x00008000
+#define FAN_EVENT_INFO_TYPE_ERROR	4
+
+struct fanotify_event_info_error {
+	struct fanotify_event_info_header hdr;
+	__s32 error;
+	__u32 error_count;
+	__kernel_fsid_t fsid;
+	__u64 ino;
+	__u32 ino_generation;
+};
+#endif
+
+static void handle_notifications(char *buffer, int len)
+{
+	struct fanotify_event_metadata *metadata;
+	struct fanotify_event_info_error *error;
+
+	for (metadata = (struct fanotify_event_metadata *) buffer;
+	     FAN_EVENT_OK(metadata, len);
+	     metadata = FAN_EVENT_NEXT(metadata, len)) {
+		if (metadata->mask != FAN_FS_ERROR) {
+			printf("unexpected FAN MARK: %llx\n", metadata->mask);
+			continue;
+		} else if (metadata->fd != FAN_NOFD) {
+			printf("Unexpected fd (!= FAN_NOFD)\n");
+			continue;
+		}
+
+		printf("FAN_FS_ERROR found len=%d\n", metadata->event_len);
+
+		error = (struct fanotify_event_info_error *) (metadata+1);
+		if (error->hdr.info_type != FAN_EVENT_INFO_TYPE_ERROR) {
+			printf("unknown record: %d\n", error->hdr.info_type);
+			continue;
+		}
+
+		printf("\tGeneric Error Record: len=%d\n", error->hdr.len);
+		printf("\tfsid: %x%x\n", error->fsid.val[0],
+		       error->fsid.val[1]);
+		printf("\terror: %d\n", error->error);
+		printf("\tinode: %llu\tgen:%u\n", error->ino,
+		       error->ino_generation);
+		printf("\terror_count: %d\n", error->error_count);
+	}
+}
+
+int main(int argc, char **argv)
+{
+	int fd;
+	char buffer[BUFSIZ];
+
+	if (argc < 2) {
+		printf("Missing path argument\n");
+		return 1;
+	}
+
+	fd = fanotify_init(FAN_CLASS_NOTIF, O_RDONLY);
+	if (fd < 0)
+		errx(1, "fanotify_init");
+
+	if (fanotify_mark(fd, FAN_MARK_ADD|FAN_MARK_FILESYSTEM,
+			  FAN_FS_ERROR, AT_FDCWD, argv[1])) {
+		errx(1, "fanotify_mark");
+	}
+
+	while (1) {
+		int n = read(fd, buffer, BUFSIZ);
+
+		if (n < 0)
+			errx(1, "read");
+
+		handle_notifications(buffer, n);
+	}
+
+	return 0;
+}