From 013c99242889dcf08d40140a651b6951e534ae7c Mon Sep 17 00:00:00 2001 From: Mike Fleetwood Date: Fri, 7 Jan 2022 17:34:49 +0000 Subject: [PATCH] Show bcache device as mount point of registered backing device (#183) A bcache device provides accelerated access to a backing device in a one to one relationship. Multiple bcache backing devices can be attached to and accelerated by the same cache device. Extending the setup from the previous commit, create an additional backing device and attach it to the same cache. # bcache make -B /dev/sdb2 # bcache attach /dev/sdc1 /dev/sdb2 # bcache show Name Type State Bname AttachToDev /dev/sdb2 1 (data) clean(running) bcache1 /dev/sdc1 /dev/sdb1 1 (data) clean(running) bcache0 /dev/sdc1 /dev/sdc1 3 (cache) active N/A N/A List a couple of bcache specific sysfs files which identify registered (active) bcache devices (components). # ls -l /sys/block/sd?/sd??/bcache/{dev,set} lrwxrwxrwx. 1 root root 0 Jan 7 10:08 /sys/block/sdb/sdb1/bcache/dev -> ../../../../../../../../../../virtual/block/bcache0 lrwxrwxrwx. 1 root root 0 Jan 7 11:53 /sys/block/sdb/sdb2/bcache/dev -> ../../../../../../../../../../virtual/block/bcache1 lrwxrwxrwx. 1 root root 0 Jan 7 11:53 /sys/block/sdc/sdc1/bcache/set -> ../../../../../../../../../../../fs/bcache/9945e165-0604-4f29-94bd-b155d01080ad As was done with previous software block devices [1][2][3][4] show the bcache (access) device as the mount point of a backing device (component). Use the /sys/block/DEV[/PTN]/bcache/dev sysfs symlinks to provide the bcache device names. Bcache cache devices (components) don't get mount points because they aren't accessible. [1] commit 8083f11d84dbd4f186271a3cdbf5170db259f8b8 Display LVM2 VGNAME as the PV's mount point (#160787) [2] commit f6c2f00df7858a7f4b97e699b9bcf1023bba850a Populate member mount point with SWRaid array device (#756829) [3] commit 538c866d099bc1f2bab3a41dc13a00b3d4336bbf Display array device as mount point of mdadm started ATARAID members (#75) [4] commit 538c866d099bc1f2bab3a41dc13a00b3d4336bbf Display array device as mount point of mdadm started ATARAID members (#75) Closes #183 - Basic support for bcache --- include/BCache_Info.h | 5 +++++ src/BCache_Info.cc | 35 ++++++++++++++++++++++++++++++----- src/GParted_Core.cc | 7 +++++++ 3 files changed, 42 insertions(+), 5 deletions(-) diff --git a/include/BCache_Info.h b/include/BCache_Info.h index 5265a547..6d24313b 100644 --- a/include/BCache_Info.h +++ b/include/BCache_Info.h @@ -36,6 +36,11 @@ class BCache_Info { public: static bool is_active(const Glib::ustring& device_path, const Glib::ustring& partition_path); + static Glib::ustring get_bcache_device(const Glib::ustring& device_path, const Glib::ustring& partition_path); + +private: + static Glib::ustring get_sysfs_bcache_path(const Glib::ustring& device_path, + const Glib::ustring& partition_path); }; diff --git a/src/BCache_Info.cc b/src/BCache_Info.cc index ff9bd105..129a5178 100644 --- a/src/BCache_Info.cc +++ b/src/BCache_Info.cc @@ -17,6 +17,8 @@ #include "BCache_Info.h" +#include // GNU version of basename() +#include #include #include @@ -29,22 +31,45 @@ namespace GParted // otherwise. Equivalent to does the directory /sys/block/DEV[/PTN]/bcache exist? bool BCache_Info::is_active(const Glib::ustring& device_path, const Glib::ustring& partition_path) { - Glib::ustring bcache_path; + return file_test(get_sysfs_bcache_path(device_path, partition_path), Glib::FILE_TEST_IS_DIR); +} + + +// Return the bcache device name for a registered bcache backing device (active +// component), or an empty string. +// E.g.: ("/dev/sdb", "/dev/sdb1") -> "/dev/bcache0" +Glib::ustring BCache_Info::get_bcache_device(const Glib::ustring& device_path, const Glib::ustring& partition_path) +{ + Glib::ustring sysfs_path = get_sysfs_bcache_path(device_path, partition_path) + "/dev"; + + char buf[128]; // Large enough for link target + // "../../../../../../../../../../virtual/block/bcache0". + ssize_t len = readlink(sysfs_path.c_str(), buf, sizeof(buf)-1); + if (len < 0) + return Glib::ustring(""); + buf[len] = '\0'; + + return "/dev/" + Glib::ustring(basename(buf)); +} + + +// Private methods + +Glib::ustring BCache_Info::get_sysfs_bcache_path(const Glib::ustring& device_path, const Glib::ustring& partition_path) +{ Glib::ustring dev_name = device_path.substr(5); // Remove leading "/dev/". if (device_path == partition_path) { // Whole drive - bcache_path = "/sys/block/" + dev_name + "/bcache"; + return "/sys/block/" + dev_name + "/bcache"; } else { // Partition on drive Glib::ustring ptn_name = partition_path.substr(5); // Remove leading "/dev/". - bcache_path = "/sys/block/" + dev_name + "/" + ptn_name + "/bcache"; + return "/sys/block/" + dev_name + "/" + ptn_name + "/bcache"; } - - return file_test(bcache_path, Glib::FILE_TEST_IS_DIR); } diff --git a/src/GParted_Core.cc b/src/GParted_Core.cc index 7dae661d..f28de6bf 100644 --- a/src/GParted_Core.cc +++ b/src/GParted_Core.cc @@ -1491,6 +1491,13 @@ void GParted_Core::set_mountpoints( Partition & partition ) partition.add_mountpoint(array_path_2); } } + else if (partition.fstype == FS_BCACHE) + { + const Glib::ustring bcache_path = BCache_Info::get_bcache_device(partition.device_path, + partition.get_path()); + if (! bcache_path.empty()) + partition.add_mountpoint(bcache_path); + } else if (partition.fstype == FS_LUKS) { LUKS_Mapping mapping = LUKS_Info::get_cache_entry( partition.get_path() );