60474dcec6
Turned out that setting a nil-UUID is no better than clearing it. What currently happens is as follows: - first, genext2fs does not generate a UUID - then we tune2fs to upgrade the filesystem - then we run fsck, which generates a random UUID - then we re-run tune2fs to set a nil-UUID So, on the target, if the file system is improperly unmounted (eg. with a power failure), on next boot, fsck may be run, and a new random UUID will be generated. *However*, fsck improperly updates the filesystem when it adds the UUID, and there are a few group descriptor checksum errors. Those errors will go undetected until the next fsck, which will then block for user input (bad on embedded systems, bad). Fix that by systematically generating a random UUID _before_ we call to fsck. A random UUID is not so bad, after all, since there are already so many sources of unpredictability in the filesystem: files date and ordering, files content (date, paths...) which renders a fixed UUID unneeded. And it is still possible to set the UUID in a post-image script if needed, anyway. Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr> Cc: Peter Korsgaard <jacmet@uclibc.org> Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com> Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
120 lines
3.4 KiB
Bash
Executable File
120 lines
3.4 KiB
Bash
Executable File
#!/bin/sh
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# genext2fs wrapper calculating needed blocks/inodes values if not specified
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set -e
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export LC_ALL=C
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CALC_BLOCKS=1
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CALC_INODES=1
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EXT_OPTS=
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EXT_OPTS_O=
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while getopts x:d:D:b:i:N:m:g:e:zfqUPhVv f
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do
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case $f in
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b) CALC_BLOCKS=0 ;;
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N) CALC_INODES=0; INODES=$OPTARG ;;
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d) TARGET_DIR=$OPTARG ;;
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esac
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done
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eval IMG="\"\${${OPTIND}}\""
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# calculate needed inodes
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if [ $CALC_INODES -eq 1 ];
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then
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INODES=$(find $TARGET_DIR | wc -l)
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INODES=$(expr $INODES + 400)
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set -- $@ -N $INODES
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fi
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# calculate needed blocks
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if [ $CALC_BLOCKS -eq 1 ];
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then
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# size ~= superblock, block+inode bitmaps, inodes (8 per block), blocks
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# we scale inodes / blocks with 10% to compensate for bitmaps size + slack
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BLOCKS=$(du -s -c -k $TARGET_DIR | grep total | sed -e "s/total//")
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BLOCKS=$(expr 500 + \( $BLOCKS + $INODES / 8 \) \* 11 / 10)
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# we add 1300 blocks (a bit more than 1 MiB, assuming 1KiB blocks) for
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# the journal if ext3/4
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# Note: I came to 1300 blocks after trial-and-error checks. YMMV.
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if [ ${GEN} -ge 3 ]; then
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BLOCKS=$(expr 1300 + $BLOCKS )
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fi
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set -- $@ -b $BLOCKS
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fi
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e2tunefsck() {
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# Upgrade the file system
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if [ $# -ne 0 ]; then
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tune2fs "$@" "${IMG}"
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fi
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# genext2fs does not generate a UUID, but fsck will whine if one is
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# is missing, so we need to add a UUID.
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# Of course, this has to happend _before_ we run fsck.
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# Although a random UUID may seem bad for reproducibility, there
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# already are so many things that are not reproducible in a
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# filesystem: file dates, file ordering, content of the files...
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tune2fs -U random "${IMG}"
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# After changing filesystem options, running fsck is required
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# (see: man tune2fs). Running e2fsck in other cases will ensure
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# coherency of the filesystem, although it is not required.
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# 'e2fsck -pDf' means:
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# - automatically repair
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# - optimise and check for duplicate entries
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# - force checking
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# Sending output to oblivion, as e2fsck can be *very* verbose,
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# especially with filesystems generated by genext2fs.
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# Exit codes 1 & 2 are OK, it means fs errors were successfully
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# corrected, hence our little trick with $ret.
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ret=0
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e2fsck -pDf "${IMG}" >/dev/null || ret=$?
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case ${ret} in
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0|1|2) ;;
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*) exit ${ret};;
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esac
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printf "\ne2fsck was successfully run on '%s' (ext%d)\n\n" \
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"${IMG##*/}" "${GEN}"
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# Remove count- and time-based checks, they are not welcome
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# on embedded devices, where they can cause serious boot-time
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# issues by tremendously slowing down the boot.
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tune2fs -c 0 -i 0 "${IMG}"
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}
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# Check we know what generation to generate
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case "${GEN}:${REV}" in
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2:0|2:1|3:1|4:1)
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;;
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*)
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printf "%s: unknown ext generation '%s' and/or revision '%s'\n" \
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"${0##*/}" "${GEN}" "${REV}" >&2
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exit 1
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;;
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esac
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# Upgrade to rev1 if needed
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if [ ${REV} -ge 1 ]; then
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EXT_OPTS_O="${EXT_OPTS_O},filetype"
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fi
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# Add a journal for ext3 and above
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if [ ${GEN} -ge 3 ]; then
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EXT_OPTS="${EXT_OPTS} -j -J size=1"
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fi
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# Add ext4 specific features
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if [ ${GEN} -ge 4 ]; then
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EXT_OPTS_O="${EXT_OPTS_O},extents,uninit_bg,dir_index"
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fi
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# Add our -O options (there will be at most one leading comma, remove it)
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if [ -n "${EXT_OPTS_O}" ]; then
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EXT_OPTS="${EXT_OPTS} -O ${EXT_OPTS_O#,}"
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fi
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# Generate and upgrade the filesystem
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genext2fs "$@"
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e2tunefsck ${EXT_OPTS}
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