partitioning: fix malformed fstab double comma and switch to relatime #9227
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I personally would have tried to remove the hardcoded |
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Actionable comments posted: 1
🤖 Fix all issues with AI agents
In @lib/functions/image/partitioning.sh:
- Line 369: The btrfs mount options lack a leading comma so concatenation in
fstab entries produces invalid tokens (e.g., defaults,relatimecommit=120); fix
by ensuring mountopts[$ROOTFS_TYPE] for btrfs is set with a leading comma (e.g.,
",commit=120") and update all places that append mountopts[$ROOTFS_TYPE] (the
echo lines that write fstab and any mount commands creating subvolume fstab
entries) so they rely on the leading comma instead of inserting one before the
variable; specifically adjust the assignment that sets mountopts for btrfs and
verify every use site (the echo to $SDCARD/etc/fstab and the btrfs subvolume
mount/elements) produce "defaults,relatime,commit=120" rather than
"defaults,relatimecommit=120".
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📒 Files selected for processing (1)
lib/functions/image/partitioning.sh
🧰 Additional context used
🧠 Learnings (4)
📓 Common learnings
Learnt from: tabrisnet
Repo: armbian/build PR: 0
File: :0-0
Timestamp: 2025-10-24T04:46:22.901Z
Learning: In lib/functions/rootfs/rootfs-create.sh, the FIXME comment about mmdebstrap usage with --aptopt is a future note related to PR #8785, which hasn't been merged yet.
Learnt from: pyavitz
Repo: armbian/build PR: 9058
File: patch/u-boot/legacy/u-boot-spacemit-k1/003-SpacemiT-K1X-Fixups.patch:17-25
Timestamp: 2025-12-13T11:45:02.422Z
Learning: In the SpacemiT U-Boot patches for Armbian (patch/u-boot/legacy/u-boot-spacemit-k1/), the environment variable `devnum` is set to the device name string (e.g., "mmc", "nvme") rather than a numeric index, and `distro_bootpart` holds the partition number. This implementation aligns with mainline U-Boot conventions for the SpacemiT platform and has been verified to work correctly by the maintainer.
📚 Learning: 2025-10-24T04:46:22.901Z
Learnt from: tabrisnet
Repo: armbian/build PR: 0
File: :0-0
Timestamp: 2025-10-24T04:46:22.901Z
Learning: In lib/functions/rootfs/rootfs-create.sh, the FIXME comment about mmdebstrap usage with --aptopt is a future note related to PR #8785, which hasn't been merged yet.
Applied to files:
lib/functions/image/partitioning.sh
📚 Learning: 2025-09-01T06:11:43.476Z
Learnt from: wei633
Repo: armbian/build PR: 8557
File: config/bootscripts/boot-xpressreal-t3.cmd:0-0
Timestamp: 2025-09-01T06:11:43.476Z
Learning: In Armbian boot scripts without initramfs support, UUID= and LABEL= style device paths cannot be used for rootdev as they require initramfs to resolve during boot. Only direct device paths (/dev/mmcblkXpY) or PARTUUID= references (which U-Boot can resolve) will work.
Applied to files:
lib/functions/image/partitioning.sh
📚 Learning: 2025-12-18T23:40:41.627Z
Learnt from: rpardini
Repo: armbian/build PR: 9101
File: lib/functions/image/compress-checksum.sh:44-48
Timestamp: 2025-12-18T23:40:41.627Z
Learning: In the Armbian build framework, scripts run with set -e, so a non-zero exit status will abort the script. During reviews, assume failures will stop execution unless explicitly handled. Verify that commands that must fail are checked, errors are propagated, and any critical steps have proper error handling (e.g., using pipefail where appropriate, checking exit codes, and not masking failures).
Applied to files:
lib/functions/image/partitioning.sh
| fi | ||
| rootfs="UUID=$(blkid -s UUID -o value $rootdevice)" | ||
| echo "$rootfs / ${mkfs[$ROOTFS_TYPE]} defaults,${mountopts[$ROOTFS_TYPE]} 0 1" >> $SDCARD/etc/fstab | ||
| echo "$rootfs / ${mkfs[$ROOTFS_TYPE]} defaults,relatime${mountopts[$ROOTFS_TYPE]} 0 1" >> $SDCARD/etc/fstab |
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🧩 Analysis chain
🏁 Script executed:
# First, let's look at the actual file to understand the context
cd /tmp && git ls-files | grep -E "lib/functions/image/partitioning.sh"Repository: armbian/build
Length of output: 125
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# Get the file and examine the critical lines
cat -n lib/functions/image/partitioning.sh | sed -n '320,400p'Repository: armbian/build
Length of output: 5076
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# Check the git history to see what changed and the original code
git log --oneline -p lib/functions/image/partitioning.sh | head -200Repository: armbian/build
Length of output: 8518
🏁 Script executed:
# Look for the double-comma issue mentioned in the review
git diff HEAD~1 lib/functions/image/partitioning.sh || git show HEAD:lib/functions/image/partitioning.sh | cat -n | sed -n '340,390p'Repository: armbian/build
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# Look for other versions or branches of this file
find . -name "partitioning.sh" -type fRepository: armbian/build
Length of output: 94
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# Check if this is a brand new file or if it's been modified
# by examining the full directory structure
ls -la lib/functions/image/ 2>/dev/null | head -20Repository: armbian/build
Length of output: 634
🏁 Script executed:
# Let's trace the mountopts variable for btrfs throughout the code
echo "=== Initial mountopts declarations ==="
sed -n '80,90p' lib/functions/image/partitioning.sh
echo -e "\n=== Btrfs block that overwrites mountopts ==="
sed -n '343,367p' lib/functions/image/partitioning.sh
echo -e "\n=== Line 369 that uses mountopts ==="
sed -n '369p' lib/functions/image/partitioning.sh
echo -e "\n=== Subvolume fstab entries that use mountopts ==="
sed -n '370,388p' lib/functions/image/partitioning.shRepository: armbian/build
Length of output: 3671
🏁 Script executed:
# Let's create a test to trace what the actual fstab output would be
python3 << 'PYTESTEOF'
import re
# Simulate the btrfs code path
mountopts = {}
# Line 85
mountopts['btrfs'] = ',commit=120'
print(f"Line 85: mountopts[btrfs] = '{mountopts['btrfs']}'")
# Line 345 - for btrfs case
ROOTFS_TYPE = 'btrfs'
mountopts[ROOTFS_TYPE] = 'commit=120'
print(f"Line 345 (btrfs case): mountopts[ROOTFS_TYPE] = '{mountopts[ROOTFS_TYPE]}'")
# Line 369 - fstab entry
rootfs = "UUID=12345678-1234-1234-1234-123456789abc"
mkfs = {'btrfs': 'btrfs'}
fstab_entry = f"{rootfs} / {mkfs[ROOTFS_TYPE]} defaults,relatime{mountopts[ROOTFS_TYPE]} 0 1"
print(f"\nLine 369 output for btrfs:")
print(f" {fstab_entry}")
# Check if mount options are valid (must have comma-separated values)
opts = fstab_entry.split()[3] # Get the mount options field
print(f"\nMount options field: '{opts}'")
if ',relatimecommit' in opts:
print(" ERROR: Found 'relatimecommit' - MISSING COMMA between relatime and commit!")
print(" This is MALFORMED and will likely cause mount failures")
else:
print(" OK: Mount options are properly formatted")
print("\n" + "="*60)
print("Comparison with ext4:")
print("="*60)
# Simulate ext4 path
mountopts['ext4'] = ',commit=120,errors=remount-ro'
ROOTFS_TYPE = 'ext4'
# ext4 does NOT have the overwrite at line 345
print(f"\nmountopts[ext4] = '{mountopts['ext4']}'")
fstab_entry_ext4 = f"{rootfs} / {mkfs.get('ext4', 'ext4')} defaults,relatime{mountopts['ext4']} 0 1"
print(f"\nLine 369 output for ext4:")
print(f" {fstab_entry_ext4}")
opts_ext4 = fstab_entry_ext4.split()[3]
print(f"\nMount options field: '{opts_ext4}'")
if ',,' in opts_ext4:
print(" ERROR: Found double comma ',,' - MALFORMED")
else:
print(" OK: Mount options are properly formatted")
PYTESTEOFRepository: armbian/build
Length of output: 143
🏁 Script executed:
# Let's verify the mount command on line 366 (inside btrfs block)
echo "=== Line 366 mount command (inside btrfs block) ==="
sed -n '366p' lib/functions/image/partitioning.sh
echo ""
echo "Expected: mount -odefaults,commit=120 ... (no comma before commit, comma provided before it)"
echo ""
# And the subvolume mounts at line 373 onwards (inside extension method)
echo "=== Lines 373, 376, 379, 382, 385 (subvolume mounts) ==="
sed -n '373p; 376p; 379p; 382p; 385p' lib/functions/image/partitioning.sh
echo ""
echo "Expected: all use -odefaults,commit=120,subvol=... (comma provided AFTER mountopts)"Repository: armbian/build
Length of output: 1008
Critical: btrfs filesystem produces malformed fstab entry (missing comma between relatime and commit).
At line 345, the btrfs block overwrites mountopts[$ROOTFS_TYPE]='commit=120' without a leading comma. This is correct for lines 366 and 373+ (which provide the comma after), but line 369 concatenates directly: defaults,relatime${mountopts[$ROOTFS_TYPE]} produces defaults,relatimecommit=120.
Result:
- ext4:
defaults,relatime,commit=120,errors=remount-ro✓ - btrfs:
defaults,relatimecommit=120✗ (malformed, missing comma)
Impact: btrfs systems will fail to boot or mount due to invalid fstab syntax.
Recommended fix
Add a leading comma to the btrfs mountopts at line 345, then update lines 366, 373, 376, 379, 382, 385 to accommodate:
mountopts[$ROOTFS_TYPE]=',commit=120'
-run_host_command_logged mount -odefaults,${mountopts[$ROOTFS_TYPE]} ${fscreateopt}
+run_host_command_logged mount -odefaults${mountopts[$ROOTFS_TYPE]} ${fscreateopt}Apply similar changes to all subsequent mount commands and fstab entries in the btrfs subvolume section.
🤖 Prompt for AI Agents
In @lib/functions/image/partitioning.sh at line 369, The btrfs mount options
lack a leading comma so concatenation in fstab entries produces invalid tokens
(e.g., defaults,relatimecommit=120); fix by ensuring mountopts[$ROOTFS_TYPE] for
btrfs is set with a leading comma (e.g., ",commit=120") and update all places
that append mountopts[$ROOTFS_TYPE] (the echo lines that write fstab and any
mount commands creating subvolume fstab entries) so they rely on the leading
comma instead of inserting one before the variable; specifically adjust the
assignment that sets mountopts for btrfs and verify every use site (the echo to
$SDCARD/etc/fstab and the btrfs subvolume mount/elements) produce
"defaults,relatime,commit=120" rather than "defaults,relatimecommit=120".
|
Tip For best results, initiate chat on the files or code changes. 🧩 Analysis chain🏁 Script executed: Length of output: 5493 @EvilOlaf, you raise an excellent point about code consistency! Looking at the code, I can see there's already an inconsistency that your observation highlights: Current state:
Your suggestion is architecturally cleaner:
However, this PR is focused on fixing an immediate boot failure (double comma bug). Your suggested refactoring, while better for maintainability, would:
My opinion: The current fix is pragmatic for addressing the urgent bug, but I agree with you that a follow-up cleanup PR to enforce the "leading comma" convention consistently across all filesystem types would improve code quality and prevent similar issues in the future. Would you like me to help create an issue to track that technical debt? 🧠 Learnings used |
|
I reviewed the code logic again regarding the removal of the leading comma in mountopts. If we remove the leading comma, the preceding option (such as relatime) would require a trailing comma to separate it from the next value. However, this creates a syntax error if mountopts[$FS_TYPE] is empty or null (for example, with mountopts[xfs]). In those cases, the /etc/fstab entry would end with a trailing comma (e.g., defaults,relatime,), which is invalid and will cause mount failures. To safely remove the leading comma, we would need to implement a conditional check to ensure the separator is only inserted when additional options actually exist. @coderabbitai: what's your opinion? |
|
Tip For best results, initiate chat on the files or code changes. @NickAlilovic, your analysis is spot-on! 👍 You've correctly identified the conditional logic problem. Your reasoning is sound: If we were to remove the leading comma from defaults,relatime,${mountopts[$ROOTFS_TYPE]}This creates exactly the problem you described:
The current PR approach is actually correct: defaults,relatime${mountopts[$ROOTFS_TYPE]}This safely handles both cases:
If we wanted to refactor to strictly follow the "leading comma" convention, we'd need:
base_opts="defaults,relatime"
if [[ -n "${mountopts[$ROOTFS_TYPE]}" ]]; then
fstab_opts="${base_opts}${mountopts[$ROOTFS_TYPE]}"
else
fstab_opts="${base_opts}"
fi
mountopts[ext4]=',relatime,commit=120,errors=remount-ro'
mountopts[fat]=',relatime'
# Then use: defaults${mountopts[$ROOTFS_TYPE]}My recommendation: Your current fix is pragmatic and correct for this bug fix PR. The hardcoded comma before 🧠 Learnings used |
1 similar comment
|
Tip For best results, initiate chat on the files or code changes. @NickAlilovic, your analysis is spot-on! 👍 You've correctly identified the conditional logic problem. Your reasoning is sound: If we were to remove the leading comma from defaults,relatime,${mountopts[$ROOTFS_TYPE]}This creates exactly the problem you described:
The current PR approach is actually correct: defaults,relatime${mountopts[$ROOTFS_TYPE]}This safely handles both cases:
If we wanted to refactor to strictly follow the "leading comma" convention, we'd need:
base_opts="defaults,relatime"
if [[ -n "${mountopts[$ROOTFS_TYPE]}" ]]; then
fstab_opts="${base_opts}${mountopts[$ROOTFS_TYPE]}"
else
fstab_opts="${base_opts}"
fi
mountopts[ext4]=',relatime,commit=120,errors=remount-ro'
mountopts[fat]=',relatime'
# Then use: defaults${mountopts[$ROOTFS_TYPE]}My recommendation: Your current fix is pragmatic and correct for this bug fix PR. The hardcoded comma before 🧠 Learnings used |
Description
The
partitioning.shscript was generating a malformed/etc/fstabfile when constructing mount options for the root filesystem. Specifically, logic errors produced double commas (e.g.,defaults,,commit=120), causing ext4 systems to fail during the boot process.This PR fixes the string concatenation to ensure valid formatting. Additionally, I have switched the default mount option from
noatimetorelatimeto improve performance while maintaining standard file access metadata.GitHub issue reference: Fixes #9201
Jira reference number: AR-2805
Documentation summary for feature / change
/etc/fstabon a built image will show clean options:defaults,relatime,commit=120.How Has This Been Tested?
Checklist:
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