automatically exclude btrfs snapshot subvolumes from 'btrfsmountedsub…

…vol' Related: #3175 (comment)
rear · May 14, 2024 · 4742906 · jsmeix · May 14, 2024 · lzaoral
1 parent 6389691
commit 4742906
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Showing 2 changed files with 17 additions and 2 deletions.
diff --git a/usr/share/rear/layout/save/GNU/Linux/230_filesystem_layout.sh b/usr/share/rear/layout/save/GNU/Linux/230_filesystem_layout.sh
@@ -434,6 +434,7 @@ fi
                     # Output header only once:
                     btrfsmountedsubvol_entry_exists="yes"
                     echo "# All mounted btrfs subvolumes (including mounted btrfs default subvolumes and mounted btrfs snapshot subvolumes)."
+                    echo "Mounted btrfs snapshot subvolumes are autoexcluded.
                     if test "$findmnt_FSROOT_works" ; then
                         echo "# Determined by the findmnt command that shows the mounted btrfs_subvolume_path."
                         echo "# Format: btrfsmountedsubvol <device> <subvolume_mountpoint> <mount_options> <btrfs_subvolume_path>"
@@ -469,7 +470,10 @@ fi
                 # Finally, test whether the btrfs subvolume listed as mounted actually exists. A running docker
                 # daemon apparently can convince the system to list a non-existing btrfs volume as mounted.
                 # See https://github.com/rear/rear/issues/1496
-                if btrfs_subvolume_exists "$subvolume_mountpoint" "$btrfs_subvolume_path"; then
+                if btrfs_snapshot_subvolume_exists "$subvolume_mountpoint" "$btrfs_subvolume_path"; then
+                    # Exclude mounted snapshot subvolumes
+                    echo "#btrfsmountedsubvol $device $subvolume_mountpoint $mount_options $btrfs_subvolume_path"
+                elif btrfs_subvolume_exists "$subvolume_mountpoint" "$btrfs_subvolume_path"; then
                     echo "btrfsmountedsubvol $device $subvolume_mountpoint $mount_options $btrfs_subvolume_path"
                 else
                     LogPrintError "Ignoring non-existing btrfs subvolume listed as mounted: $subvolume_mountpoint"

diff --git a/usr/share/rear/lib/filesystems-functions.sh b/usr/share/rear/lib/filesystems-functions.sh
@@ -3,16 +3,27 @@
 #
 # File system support functions
 
+function btrfs_snapshot_subvolume_exists() {
+    # returns true if the btrfs snapshot subvolume ($2) exists in the Btrfs
+    # file system at the mount point ($1).
+
+    # Use -s so that btrfs subvolume list considers snapshots only
+    btrfs_subvolume_exists "$1" "$2" "-s"
+}
+
 function btrfs_subvolume_exists() {
     # returns true if the btrfs subvolume ($2) exists in the Btrfs file system at the mount point ($1).
     local subvolume_mountpoint="$1" btrfs_subvolume_path="$2"
 
+    # extra options for the btrfs subvolume list command ($3)
+    local btrfs_extra_opts="$3"
+
     # A root subvolume can be assumed to always exist
     [ "$btrfs_subvolume_path" == "/" ] && return 0
 
     # A non-root subvolume exists if the btrfs subvolume list contains its complete path at the end of one line.
     # This code deliberately uses a plain string comparison rather than a regexp.
-    btrfs subvolume list -a "$subvolume_mountpoint" | sed -e 's; path <FS_TREE>/; path ;' |
+    btrfs subvolume list -a $btrfs_extra_opts "$subvolume_mountpoint" | sed -e 's; path <FS_TREE>/; path ;' |
     awk -v path="$btrfs_subvolume_path" '
         BEGIN {
             match_string = " path " path;