From 9a1b9cdbee8f903436bf9056ed877ad3f9f495ca Mon Sep 17 00:00:00 2001 From: sneak Date: Wed, 11 Nov 2026 03:54:15 +0000 Subject: [PATCH] README: guard the daily cron scan against an unmounted disk (closes #175) A disk that is not mounted leaves its mount point an empty directory. scan then deletes every record under it, and the next scan reads every file again. The README now says so. Its cron line runs scan only when mountpoint finds the disks mounted, and one sentence says which mount points to test. Model: opus-5-5 --- README.md | 13 +++++++++---- TODO.md | 3 +++ 2 files changed, 12 insertions(+), 4 deletions(-) diff --git a/README.md b/README.md index 2db44c6..782d1b5 100644 --- a/README.md +++ b/README.md @@ -114,15 +114,20 @@ docker run --rm -v /srv:/srv:ro -v /var/lib/sfdupes:/var/lib/sfdupes \ Run `scan` as root, so that it can read every file. `scan` warns about a directory it cannot read, and about a new or changed file it cannot read. It skips the path and deletes the records at or below it (see "Rules for the -walk"). As the file `/etc/cron.d/sfdupes`: +walk"). + +An unmounted disk leaves its mount point empty, so `scan` deletes every record +under it, and the next scan reads every file on the disk again. Test the mount +point of each disk at or below `/srv` with its own `mountpoint -q`, joined with +`&&`, and test `/srv` only when it is one. As the file `/etc/cron.d/sfdupes`: ``` -30 3 * * * root /usr/local/bin/sfdupes scan /srv 2>>/var/log/sfdupes.log || tail -n 3 /var/log/sfdupes.log +30 3 * * * root if mountpoint -q /srv; then /usr/local/bin/sfdupes scan /srv 2>>/var/log/sfdupes.log || tail -n 3 /var/log/sfdupes.log; else echo "a disk is not mounted; scan of /srv skipped"; fi ``` - The first scan creates `/var/lib/sfdupes/db.sqlite` and its directory. To keep - the database elsewhere, put `SFDUPES_DATABASE=/path/to/db.sqlite` before the - command on the same line. + the database elsewhere, put `SFDUPES_DATABASE=/path/to/db.sqlite` directly + before `/usr/local/bin/sfdupes`. - `scan` writes nothing to stdout. Its stderr, appended here to `/var/log/sfdupes.log`, holds: - one line naming the database; diff --git a/TODO.md b/TODO.md index 9b7d422..13e2823 100644 --- a/TODO.md +++ b/TODO.md @@ -29,6 +29,9 @@ Newest first. An entry ends with its date and its issue or branch, where those are known. +- `README.md` says what a disk that is not mounted does to the database. The + daily `cron` line runs `scan` only when `mountpoint` reports `/srv` as mounted + (2026-11-11, https://git.eeqj.de/sneak/sfdupes/issues/175) - The help of `sfdupes` and of `scan` names the database, its default path and `SFDUPES_DATABASE`. The help of `report` and `trees` lists the columns, the order of the rows and the escapes. The help of `info` lists its lines. The