From 42f04a0f77ee94b01d652d6c11d10e85aa46a897 Mon Sep 17 00:00:00 2001 From: Peter Rajnoha Date: Fri, 1 Apr 2016 17:04:11 +0200 Subject: [PATCH] dev-cache: skip VGID/LVID indexing if /sys/dev/block is not present /sys/dev/block is available since kernel version 2.2.26 (~ 2008): https://www.kernel.org/doc/Documentation/ABI/testing/sysfs-dev The VGID/LVID indexing code relies on this feature so skip indexing if it's not available to avoid error messages about inability to open /sys/dev/block directory. We're not going to provide fallback code to read the /sys/block/ instead in this case as that's not that efficient - it needs extra reads for getting major:minor and reading partitions would also pose further reads and that's not worth it. --- lib/device/dev-cache.c | 35 +++++++++++++++++++++++++++-------- 1 file changed, 27 insertions(+), 8 deletions(-) diff --git a/lib/device/dev-cache.c b/lib/device/dev-cache.c index 84bd85b12..8461f40a2 100644 --- a/lib/device/dev-cache.c +++ b/lib/device/dev-cache.c @@ -818,9 +818,8 @@ static int _dev_cache_iterate_devs_for_index(void) return r; } -static int _dev_cache_iterate_sysfs_for_index(void) +static int _dev_cache_iterate_sysfs_for_index(const char *path) { - char path[PATH_MAX]; char devname[PATH_MAX]; DIR *d; struct dirent *dirent; @@ -830,11 +829,6 @@ static int _dev_cache_iterate_sysfs_for_index(void) int partial_failure = 0; int r = 0; - if (dm_snprintf(path, sizeof(path), "%sdev/block", dm_sysfs_dir()) < 0) { - log_error("_dev_cache_iterate_sysfs_for_index: dm_snprintf failed."); - return 0; - } - if (!(d = opendir(path))) { log_sys_error("opendir", path); return 0; @@ -876,11 +870,36 @@ static int _dev_cache_iterate_sysfs_for_index(void) int dev_cache_index_devs(void) { + static int sysfs_has_dev_block = -1; + char path[PATH_MAX]; + + if (dm_snprintf(path, sizeof(path), "%sdev/block", dm_sysfs_dir()) < 0) { + log_error("dev_cache_index_devs: dm_snprintf failed."); + return 0; + } + + /* Skip indexing if /sys/dev/block is not available.*/ + if (sysfs_has_dev_block == -1) { + struct stat info; + if (stat(path, &info) == 0) + sysfs_has_dev_block = 1; + else { + if (errno == ENOENT) { + sysfs_has_dev_block = 0; + return 1; + } else { + log_sys_error("stat", path); + return 0; + } + } + } else if (!sysfs_has_dev_block) + return 1; + int with_udev = obtain_device_list_from_udev() && udev_get_library_context(); return with_udev ? _dev_cache_iterate_devs_for_index() - : _dev_cache_iterate_sysfs_for_index(); + : _dev_cache_iterate_sysfs_for_index(path); } #ifdef UDEV_SYNC_SUPPORT