128 lines
3.6 KiB
Diff
128 lines
3.6 KiB
Diff
From 39849d97765ed133e0e7ee6eb87ecf5e20eb0d0e Mon Sep 17 00:00:00 2001
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From: Nikolay Borisov <nborisov@suse.com>
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Date: Thu, 30 Sep 2021 15:06:33 +0300
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Subject: [PATCH 2/3] btrfs-progs: Ignore devices representing paths in
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multipath
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Currently btrfs-progs will happily enumerate any device which has a
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btrfs filesystem on it irrespective of its type. For the majority of
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use cases that's fine and there haven't been any problems with that.
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However, there was a recent report that in multipath scenario when
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running "btrfs fi show" after a path flap (path going down and then
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coming back up) instead of the multipath device being show the device
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which represents the flapped path is shown. So a multipath filesystem
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might look like:
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Label: none uuid: d3c1261f-18be-4015-9fef-6b35759dfdba
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Total devices 1 FS bytes used 192.00KiB
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devid 1 size 10.00GiB used 536.00MiB path /dev/mapper/3600140501cc1f49e5364f0093869c763
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/dev/mapper/xxx is actually backed by an arbitrary number of paths,
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which in turn are presented to the system as ordinary scsi devices i.e
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/dev/sdX. If a path flaps and a user re-runs 'btrfs fi show' the output
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would look like:
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Label: none uuid: d3c1261f-18be-4015-9fef-6b35759dfdba
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Total devices 1 FS bytes used 192.00KiB
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devid 1 size 10.00GiB used 536.00MiB path /dev/sdd
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This only occurs on unmounted filesystems as those are enumerated by
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btrfs-progs, for mounted filesystem the kernel properly deals only with
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the actual multipath device.
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Turns out the output of this command is consumed by libraries and the
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presence of a path device rather than the actual multipath causes
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issues.
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Fix this by checking for the presence of DM_MULTIPATH_DEVICE_PATH
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udev attribute as multipath path devices are tagged with this attribute
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by the multipath udev scripts.
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Signed-off-by: Nikolay Borisov <nborisov@suse.com>
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---
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common/device-scan.c | 48 ++++++++++++++++++++++++++++++++++++++++++++
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1 file changed, 48 insertions(+)
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diff --git a/common/device-scan.c b/common/device-scan.c
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index b5bfe844104b..311673e6b66e 100644
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--- a/common/device-scan.c
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+++ b/common/device-scan.c
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@@ -14,6 +14,10 @@
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* Boston, MA 021110-1307, USA.
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*/
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+#ifdef STATIC_BUILD
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+#undef HAVE_LIBUDEV
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+#endif
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+
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#include "kerncompat.h"
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#include <sys/ioctl.h>
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#include <stdlib.h>
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@@ -39,6 +43,10 @@
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#include "kernel-shared/zoned.h"
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#include "ioctl.h"
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+#ifdef HAVE_LIBUDEV
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+#include <libudev.h>
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+#endif
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+
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static int btrfs_scan_done = 0;
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/*
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@@ -364,6 +372,43 @@ void free_seen_fsid(struct seen_fsid *seen_fsid_hash[])
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}
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}
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+#ifdef HAVE_LIBUDEV
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+static bool is_path_device(char *device_path)
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+{
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+ struct udev *udev = NULL;
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+ struct udev_device *dev = NULL;
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+ struct stat dev_stat;
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+ const char *val;
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+ bool ret = false;
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+
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+ if (stat(device_path, &dev_stat) < 0)
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+ return false;
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+
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+ udev = udev_new();
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+ if (!udev)
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+ goto out;
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+
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+ dev = udev_device_new_from_devnum(udev, 'b', dev_stat.st_rdev);
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+ if (!dev)
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+ goto out;
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+
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+ val = udev_device_get_property_value(dev, "DM_MULTIPATH_DEVICE_PATH");
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+ if (val && atoi(val) > 0)
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+ ret = true;
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+out:
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+ udev_device_unref(dev);
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+ udev_unref(udev);
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+
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+ return ret;
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+}
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+#else
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+static bool is_path_device(char *device_path)
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+{
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+ return false;
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+}
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+#endif
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+
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+
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int btrfs_scan_devices(int verbose)
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{
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int fd = -1;
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@@ -394,6 +439,9 @@ int btrfs_scan_devices(int verbose)
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/* if we are here its definitely a btrfs disk*/
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strncpy_null(path, blkid_dev_devname(dev));
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+ if (is_path_device(path))
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+ continue;
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+
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fd = open(path, O_RDONLY);
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if (fd < 0) {
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error("cannot open %s: %m", path);
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--
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2.25.1
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