@@ -26,7 +26,7 @@ TESTS = fsck-tests.sh convert-tests.sh
INSTALL = install
prefix ?= /usr/local
bindir = $(prefix)/bin
-lib_LIBS = -luuid -lblkid -lm -lz -llzo2 -L.
+lib_LIBS = -ludev -luuid -lblkid -lm -lz -llzo2 -L.
libdir ?= $(prefix)/lib
incdir = $(prefix)/include/btrfs
LIBS = $(lib_LIBS) $(libs_static)
@@ -38,6 +38,7 @@
#include <linux/kdev_t.h>
#include <limits.h>
#include <blkid/blkid.h>
+#include <libudev.h>
#include "kerncompat.h"
#include "radix-tree.h"
#include "ctree.h"
@@ -2181,20 +2182,34 @@ int test_dev_for_mkfs(char *file, int force_overwrite, char *estr)
return 0;
}
-int btrfs_scan_devices()
+static int scan_device(const char *path)
+{
+ int rc;
+ int fd = open(path, O_RDONLY);
+ struct btrfs_fs_devices *devs = NULL;
+ u64 ndevs;
+
+ if (fd < 0) {
+ printf("ERROR: could not open %s\n", path);
+ return 1;
+ }
+
+ rc = btrfs_scan_one_device(fd, path, &devs, &ndevs, BTRFS_SUPER_INFO_OFFSET, 0);
+ if (rc)
+ printf("ERROR: could not scan %s\n", path);
+
+ close(fd);
+ return rc;
+}
+
+
+static int btrfs_scan_devices_by_blkid(void)
{
- int fd = -1;
- int ret;
- u64 num_devices;
- struct btrfs_fs_devices *tmp_devices;
blkid_dev_iterate iter = NULL;
blkid_dev dev = NULL;
blkid_cache cache = NULL;
char path[PATH_MAX];
- if (btrfs_scan_done)
- return 0;
-
if (blkid_get_cache(&cache, 0) < 0) {
printf("ERROR: lblkid cache get failed\n");
return 1;
@@ -2209,29 +2224,73 @@ int btrfs_scan_devices()
/* if we are here its definitely a btrfs disk*/
strncpy(path, blkid_dev_devname(dev), PATH_MAX);
- fd = open(path, O_RDONLY);
- if (fd < 0) {
- printf("ERROR: could not open %s\n", path);
- continue;
- }
- ret = btrfs_scan_one_device(fd, path, &tmp_devices,
- &num_devices, BTRFS_SUPER_INFO_OFFSET, 0);
- if (ret) {
- printf("ERROR: could not scan %s\n", path);
- close (fd);
- continue;
- }
-
- close(fd);
+ scan_device(path);
}
blkid_dev_iterate_end(iter);
blkid_put_cache(cache);
- btrfs_scan_done = 1;
-
return 0;
}
+static int btrfs_scan_devices_by_udev(void)
+{
+ int rc = 1;
+ struct udev *udev = NULL;
+ struct udev_enumerate *en = NULL;
+ struct udev_list_entry *ent, *devs;
+
+ udev = udev_new();
+ if (!udev)
+ goto done;
+ en = udev_enumerate_new(udev);
+ if (!en)
+ goto done;
+
+ udev_enumerate_add_match_subsystem(en, "block");
+ if (udev_enumerate_scan_devices(en) != 0)
+ goto done;
+ devs = udev_enumerate_get_list_entry(en);
+ if (!devs)
+ goto done;
+
+ udev_list_entry_foreach(ent, devs) {
+ const char *val, *name = udev_list_entry_get_name(ent);
+ struct udev_device *dev = udev_device_new_from_syspath(udev, name);
+
+ if (!dev)
+ continue;
+ val = udev_device_get_property_value(dev, "ID_FS_TYPE");
+ if (val && strcmp(val, "btrfs") == 0) {
+ const char *path = udev_device_get_devnode(dev);
+ if (path)
+ scan_device(path);
+ }
+ udev_device_unref(dev);
+ }
+
+ rc = 0;
+done:
+ udev_enumerate_unref(en);
+ udev_unref(udev);
+
+ return rc;
+}
+
+int btrfs_scan_devices()
+{
+ int rc = 1;
+
+ if (btrfs_scan_done)
+ return 0;
+
+ rc = btrfs_scan_devices_by_udev();
+ if (rc)
+ rc = btrfs_scan_devices_by_blkid();
+
+ btrfs_scan_done = 1;
+ return rc;
+}
+
int is_vol_small(char *file)
{
int fd = -1;
Currently btrfs uses libblkid to scan for block devices with BTRFS. The disadvantage is that this method is expensive. The udevd maintains information about all block devices in udev db and all devices are probed by udevd (it's linked with libblkid). We don't have to duplicate this thing in btrfs. This patch links btrfs with libudev, the original blkid based method is used as fallback (for systems without udev, etc.) Note that btrfs-progs project does not use autoconf, so dependence on libudev is hardcoded to Makefile for now. It would be probably better to add ./configure script to the project and make dependence on libudev optional. udev: # time ./btrfs device scan Scanning for Btrfs filesystems real 0m0.012s user 0m0.004s sys 0m0.003s blkid: # time ./btrfs device scan Scanning for Btrfs filesystems real 0m0.076s user 0m0.008s sys 0m0.024s Signed-off-by: Karel Zak <kzak@redhat.com> --- Makefile | 2 +- utils.c | 107 +++++++++++++++++++++++++++++++++++++++++++++++++-------------- 2 files changed, 84 insertions(+), 25 deletions(-)