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kdave / btrfsmaintenance

Scripts for btrfs maintenance tasks like periodic scrub, balance, trim or defrag on selected mountpoints or directories.
GNU General Public License v2.0
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Mountpoint "auto" can fail for read-only mounts #123

Open unterkomplex opened 1 month ago

unterkomplex commented 1 month ago

I encountered one issue while using the option to automatically process all mountpoints BTRFS_SCRUB_MOUNTPOINTS="auto"

The script returns a single mountpoint for each filesystem MNT=$(findmnt --types btrfs --first-only --noheadings --output "TARGET" --source "$DEVICE") https://github.com/kdave/btrfsmaintenance/blob/b1e70f6c99797def13c1d302a603e18cce701a8d/btrfsmaintenance-functions#L25C10-L25C84

This fails if there are both read-only and read-write mounts and findmnt returns a ro mountpoint

In order to fix it I think it would be sufficient to add --options rw MNT=$(findmnt --types btrfs --first-only --options rw --noheadings --output "TARGET" --source "$DEVICE")

Example output from Fedora IoT on BTRFS filesystem with /sysroot mounted as ro

[root@pi ~]# findmnt --types btrfs --noheadings --output "TARGET" --source "/dev/sda1"
/sysroot
/
/etc
/usr
/sysroot/ostree/deploy/fedora-iot/var
/var
/var/mnt/ssd
[root@pi ~]# findmnt --types btrfs --first-only --noheadings --output "TARGET" --source "/dev/sda1"
/sysroot
[root@pi ~]# findmnt --types btrfs --first-only --options rw --noheadings --output "TARGET" --source "/dev/sda1"
/

[root@pi ~]# journalctl -b0 -u btrfs-scrub.service 
Jul 08 03:09:39 pi btrfs-scrub.sh[1283]: Running scrub on /sysroot
Jul 08 03:09:39 pi btrfs-scrub.sh[1283]: RAID level is not 5 or 6, parallel device scrubbing
Jul 08 03:09:39 pi btrfs-scrub.sh[1283]: ERROR: scrubbing /sysroot failed for device id 1: ret=-1, errno=30 (Read-only>
Jul 08 03:09:39 pi btrfs-scrub.sh[1283]: Starting scrub on devid 1
Jul 08 03:09:39 pi btrfs-scrub.sh[1283]: Scrub device /dev/sda1 (id 1) canceled
Jul 08 03:09:39 pi btrfs-scrub.sh[1283]: Scrub started:    Mon Jul  8 03:09:39 2024
Jul 08 03:09:39 pi btrfs-scrub.sh[1283]: Status:           aborted
Jul 08 03:09:39 pi btrfs-scrub.sh[1283]: Duration:         0:00:00
Jul 08 03:09:39 pi btrfs-scrub.sh[1283]: Total to scrub:   0.00B
Jul 08 03:09:39 pi btrfs-scrub.sh[1283]: Rate:             0.00B/s
Jul 08 03:09:39 pi btrfs-scrub.sh[1283]: Error summary:    no errors found