[gparted] Remove extra execution of blkid for whole disk devices (#131)

[Curtis Gedak <gedakc src gnome org>]

commit 416027de643acd0d357963ccbac223a2fcf7804c
Author: Mike Fleetwood <mike fleetwood googlemail com>
Date:   Sun Jan 24 16:19:55 2021 +0000

    Remove extra execution of blkid for whole disk devices (#131)
    
    On Fedora 31 with this simple disk layout where both sdb and sdc are
    completely empty:
        # lsblk -o name,maj:min,rm,size,ro,type,fstype,label,mountpoint
        NAME            MAJ:MIN RM  SIZE RO TYPE FSTYPE      LABEL MOUNTPOINT
        sda               8:0    0   20G  0 disk
        |-sda1            8:1    0    1G  0 part ext4              /boot
        \-sda2            8:2    0   19G  0 part LVM2_member
          |-fedora-root 253:0    0   17G  0 lvm  ext4              /
          \-fedora-swap 253:1    0    2G  0 lvm  swap              [SWAP]
        sdb               8:16   0    8G  0 disk
        sdc               8:32   0    8G  0 disk
        sr0              11:0    1 1024M  0 rom
        # blkid /dev/sda /dev/sda1 /dev/sda2 /dev/sdb /dev/sdc
        /dev/sda: PTUUID="5012fb1f" PTTYPE="dos"
        /dev/sda1: UUID="3cd48816-7817-4636-9fec-5f1afe76c1b2" TYPE="ext4" PARTUUID="5012fb1f-01"
        /dev/sda2: UUID="PH94ej-C8xU-bnMJ-UIh8-ZimI-4B7f-dHlZxh" TYPE="LVM2_member" PARTUUID="5012fb1f-02"
    
    Stracing GParted shows extra executions of blkid:
        # strace -f -q -bexecve -eexecve ./gpartedbin 2>&1 1> /dev/null | egrep -v 'ENOENT|SIGCHLD'
        ...
        [pid  7659] execve("/usr/sbin/blkid", ["blkid", "/dev/sda", "/dev/sda1", "/dev/sda2", "/dev/sdb", 
"/dev/sdc"], 0x1d300f0 /* 32 vars */ <detached ...>
        [pid  7660] execve("/usr/sbin/blkid", ["blkid", "/dev/sdb"], 0x1d300f0 /* 32 vars */ <detached ...>
        [pid  7661] execve("/usr/sbin/blkid", ["blkid", "/dev/sdc"], 0x1d300f0 /* 32 vars */ <detached ...>
        ...
    
    blkid is only run again for sdb and sdc, not sda, because blkid didn't
    report anything for them from the first execution.  GParted needs blkid
    identification of whole disk devices to ensure that ISO9660 images on
    whole disk devices are correctly identified [1].  Now the first run of
    blkid passes all the device names, so this additional execution of blkid
    won't get any extra information and is redundant.  Therefore remove this
    unnecessary code.
    
    [1] b2190372d04f09bd38a7395b38e43034f1733d81
        Ensure blkid FS_Info cache has entries for all whole disk devices
        (#771244)
    
    Closes #131 - GParted hangs when non-named device is hung

 src/FS_Info.cc | 20 +++-----------------
 1 file changed, 3 insertions(+), 17 deletions(-)
---
diff --git a/src/FS_Info.cc b/src/FS_Info.cc
index ecc56696..750a2d49 100644
--- a/src/FS_Info.cc
+++ b/src/FS_Info.cc
@@ -14,9 +14,9 @@
  *  along with this program; if not, see <http://www.gnu.org/licenses/>.
  */
 
+
 #include "FS_Info.h"
 #include "BlockSpecial.h"
-#include "Proc_Partitions_Info.h"
 #include "Utils.h"
 
 #include <glibmm/ustring.h>
@@ -24,6 +24,7 @@
 #include <glibmm/shell.h>
 #include <vector>
 
+
 namespace GParted
 {
 
@@ -208,25 +209,10 @@ const FS_Entry & FS_Info::get_cache_entry_by_path( const Glib::ustring & path )
 void FS_Info::load_fs_info_cache(const std::vector<Glib::ustring>& paths)
 {
        fs_info_cache.clear();
-       // Run "blkid" and load entries into the cache.
        run_blkid_load_cache(paths);
-
-       // (#771244) Ensure the cache has entries for all whole disk devices, even if
-       // those entries are blank.  Needed so that an ISO9660 image stored on a whole
-       // disk device is detected before any embedded partitions within the image.
-       const BlockSpecial empty_bs = BlockSpecial();
-       std::vector<Glib::ustring> all_devices = Proc_Partitions_Info::get_device_paths();
-       for ( unsigned int i = 0 ; i < all_devices.size() ; i ++ )
-       {
-               const FS_Entry & fs_entry = get_cache_entry_by_path( all_devices[i] );
-               if ( fs_entry.path == empty_bs )
-               {
-                       // Run "blkid PATH" and load entry into cache for missing entries.
-                       load_fs_info_cache_extra_for_path( all_devices[i] );
-               }
-       }
 }
 
+
 void FS_Info::load_fs_info_cache_extra_for_path( const Glib::ustring & path )
 {
        std::vector<Glib::ustring> one_path;