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Changed iomplementation of deleting snaps to be a bit better debuggable
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with additional steps and stored paths. Thought the error message
sometimes appearing might be related to wrong handling of globs etc.
Don't think so anymore, as that error message seems to come before
deleting at all.
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@ams-tschoening
ams-tschoening committed Jul 24, 2022
1 parent db50064 commit a12b96e
Showing 1 changed file with 20 additions and 24 deletions.
44 changes: 20 additions & 24 deletions btrfs-auto-snapshot
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Original file line number Diff line number Diff line change
Expand Up @@ -82,7 +82,7 @@ usage()
-q, --quiet Suppress warning and notices on STDOUT
-v, --verbose Print info messages
-w, --writeable Create writeable snapshots instead of read-only
name Filesystem name(s), or '//' for all filesystems
name File system name(s), or '//' for all file systems
"
}

Expand Down Expand Up @@ -291,7 +291,7 @@ argsp_cmdline()
then
if [ "${ret_val[help]}" -eq 0 ]
then
log error "The filesystem argument list is empty."
log error "The file system argument list is empty."
log error "Please see $0 --help."
argsp_cmdline_exit=${ERR_FS_MISSING}
kill -SIGUSR1 $$
Expand Down Expand Up @@ -395,7 +395,7 @@ btrfs_subvols_calc()
ret_val+=("${mp}")

# The following seems to return relative paths based to the BTRFS root always,
# which might be empty or "@" or ... and is different to the filesystem root "/".
# which might be empty or "@" or ... and is different to the file system root "/".
mp_subvols="$(btrfs subvolume list -o "${mp}" | awk '{print $9}')"

# Subvolumes seem to have no parent UUID, while snapshots are "readonly" most
Expand All @@ -406,7 +406,7 @@ btrfs_subvols_calc()
# Some found subvolumes might be children of the current mountpoint, but still be
# mounted somewhere else on their own and therefore need to be ignored, as all
# mountpoints get processed individually already. To make things worse, paths in
# the filesystem expected by some BTRFS-tools might be different than the path of
# the file system expected by some BTRFS-tools might be different than the path of
# some subvolume from BTRFS's perspective and as output by some tools like "list".
# So resulting paths need to be build by using the current mountpoint, it's own
# subvolume path and the currently processed subvolume.
Expand All @@ -425,7 +425,7 @@ btrfs_subvols_calc()
local pattern
local matches

# Map subvolume path to filesystem path.
# Map subvolume path to file system path.
abs_path="$(echo "${subvol}" | sed -r "s!^${mp_subvol}!${mp}!")"
abs_path="$(echo "${abs_path}" | sed -r 's!^//!/!')"

Expand Down Expand Up @@ -477,7 +477,7 @@ btrfs_wrk_paths_check()
matches="$(echo "${patterns}" | grep --count -F -f - -x <(echo "${i}"))"
if [ "${matches}" = '0' ]
then
log err "It appears that '${i}' is not a BTRFS filesystem!"
log err "It appears that '${i}' is not a BTRFS file system!"
exit ${ERR_FS_NO_BTRFS}
fi
done
Expand All @@ -487,10 +487,12 @@ btrfs_wrk_paths_check()
# Create snapshots using the paths
#
# @param[in] The paths to work with.
# @param[in] Snapshot name to create.
#
btrfs_snaps_do()
{
local -r wrk_paths="${1:?No paths given.}"
local -r snap_name="${2:?No snap name given.}"

log info "Doing snapshots of $wrk_paths"

Expand All @@ -508,14 +510,15 @@ btrfs_snaps_do()
# already.
log notice "$( ${dry_run} btrfs subvolume snapshot \
${writeable} "${i}" \
"${i%/}/${DEF_SNAPS_DIR}/${snapname}" )"
"${i%/}/${DEF_SNAPS_DIR}/${snap_name}" )"
done
}

##
# Cleanup snapshots depending on how many to keep and if to cleanup at all.
#
# @param[in] The paths to work with.
# @param[in] Pattern to find snapshot names for the current prefix and label.
#
btrfs_snaps_rm_if()
{
Expand All @@ -525,13 +528,12 @@ btrfs_snaps_rm_if()
fi

local -r wrk_paths="${1:?No paths given.}"
local -r snap_patt="${2:?No snap pattern given.}"

log info "Destroying all but the newest ${keep} snapshots"

for i in $wrk_paths
do
fs_keep="${keep}"

# We are only interested in snaps this time, which follow a hard-coded naming
# scheme currently. This makes it easy to ignore all subvolumes being children of
# the current path for some reason and therefore present in the output. We either
Expand All @@ -541,22 +543,15 @@ btrfs_snaps_rm_if()
# it's somewhat safe to remove based on conventions.
snaps="$(btrfs subvolume list -g -o -s --sort=gen "${i}")"
paths="$(echo "${snaps}" | sort -r -n -k 4 | awk '{print $NF}')"
paths="$(echo "${paths}" | sed "#/${DEF_SNAPS_DIR}/#!d")"
paths="$(echo "${paths}" | sed "\#/${DEF_SNAPS_DIR}/#!d")"
paths="$(echo "${paths}" | sed -r "s!^.+/${DEF_SNAPS_DIR}/!${i}/${DEF_SNAPS_DIR}/!")"
paths="$(echo "${paths}" | sed -r "s!^//${DEF_SNAPS_DIR}/!/${DEF_SNAPS_DIR}/!")"
paths="$(echo "${paths}" | sed -r "\#/${DEF_SNAPS_DIR}/${snap_patt}#!d")"
paths="$(echo "${paths}" | tail -n "+$((keep + 1))")"

while IFS= read -r j
do
if [ -z "${j#"$snapglob"}" ]
then
continue
fi

fs_keep=$(( fs_keep - 1 ))
if [ ${fs_keep} -lt 0 ]
then
log notice "$( ${dry_run} btrfs subvolume delete -c "${j}" )"
fi
log notice "$( ${dry_run} btrfs subvolume delete -c "${j}" )"
done <<< "${paths}"
done
}
Expand Down Expand Up @@ -592,8 +587,9 @@ then
exit $ERR_SUCCESS
fi

snapname=${prefix}_${label}_$(date +%F-%H%M)
snapglob="${DEF_SNAPS_DIR}/${prefix}_${label}????????????????"
snap_name="${prefix}_${label}_$(date +%F-%H%M)"
snap_patt='[[:digit:]]{4}-[[:digit:]]{2}-[[:digit:]]{2}-[[:digit:]]{4}'
snap_patt="${prefix}_${label}_${snap_patt}"

btrfs_mounts="$(btrfs_mounts_calc)"
btrfs_subvols_txt="$(echo "${btrfs_mounts}" | btrfs_subvols_calc)"
Expand All @@ -607,7 +603,7 @@ else
fi

btrfs_wrk_paths_check "${wrk_paths}"
btrfs_snaps_do "${wrk_paths}"
btrfs_snaps_rm_if "${wrk_paths}"
btrfs_snaps_do "${wrk_paths}" "${snap_name}"
btrfs_snaps_rm_if "${wrk_paths}" "${snap_patt}"

# vim: set expandtab:ts=4:sw=4

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