From: Viacheslav Dubeyko slava@dubeyko.com
[ Upstream commit d3ed6d6981f4756f145766753c872482bc3b28d3 ]
The generic/001 test of xfstests suite fails and corrupts the HFS volume:
sudo ./check generic/001 FSTYP -- hfs PLATFORM -- Linux/x86_64 hfsplus-testing-0001 6.15.0-rc2+ #3 SMP PREEMPT_DYNAMIC Fri Apr 25 17:13:00 PDT 2> MKFS_OPTIONS -- /dev/loop51 MOUNT_OPTIONS -- /dev/loop51 /mnt/scratch
generic/001 32s ... _check_generic_filesystem: filesystem on /dev/loop50 is inconsistent (see /home/slavad/XFSTESTS-2/xfstests-dev/results//generic/001.full for details)
Ran: generic/001 Failures: generic/001 Failed 1 of 1 tests
fsck.hfs -d -n ./test-image.bin ** ./test-image.bin (NO WRITE) Using cacheBlockSize=32K cacheTotalBlock=1024 cacheSize=32768K. Executing fsck_hfs (version 540.1-Linux). ** Checking HFS volume. The volume name is untitled ** Checking extents overflow file. ** Checking catalog file. Unused node is not erased (node = 2) Unused node is not erased (node = 4) <skipped> Unused node is not erased (node = 253) Unused node is not erased (node = 254) Unused node is not erased (node = 255) Unused node is not erased (node = 256) ** Checking catalog hierarchy. ** Checking volume bitmap. ** Checking volume information. Verify Status: VIStat = 0x0000, ABTStat = 0x0000 EBTStat = 0x0000 CBTStat = 0x0004 CatStat = 0x00000000 ** The volume untitled was found corrupt and needs to be repaired. volume type is HFS primary MDB is at block 2 0x02 alternate MDB is at block 20971518 0x13ffffe primary VHB is at block 0 0x00 alternate VHB is at block 0 0x00 sector size = 512 0x200 VolumeObject flags = 0x19 total sectors for volume = 20971520 0x1400000 total sectors for embedded volume = 0 0x00
This patch adds logic of clearing the deleted b-tree node.
sudo ./check generic/001 FSTYP -- hfs PLATFORM -- Linux/x86_64 hfsplus-testing-0001 6.15.0-rc2+ #3 SMP PREEMPT_DYNAMIC Fri Apr 25 17:13:00 PDT 2025 MKFS_OPTIONS -- /dev/loop51 MOUNT_OPTIONS -- /dev/loop51 /mnt/scratch
generic/001 9s ... 32s Ran: generic/001 Passed all 1 tests
fsck.hfs -d -n ./test-image.bin ** ./test-image.bin (NO WRITE) Using cacheBlockSize=32K cacheTotalBlock=1024 cacheSize=32768K. Executing fsck_hfs (version 540.1-Linux). ** Checking HFS volume. The volume name is untitled ** Checking extents overflow file. ** Checking catalog file. ** Checking catalog hierarchy. ** Checking volume bitmap. ** Checking volume information. ** The volume untitled appears to be OK.
Signed-off-by: Viacheslav Dubeyko slava@dubeyko.com Reviewed-by: Johannes Thumshirn johannes.thumshirn@wdc.com Link: https://lore.kernel.org/r/20250430001211.1912533-1-slava@dubeyko.com Signed-off-by: Viacheslav Dubeyko slava@dubeyko.com Signed-off-by: Sasha Levin sashal@kernel.org ---
LLM Generated explanations, may be completely bogus:
Based on my analysis of the commit and the surrounding code, I can now provide a determination on whether this should be backported to stable kernel trees.
**Backport Status: YES**
This commit should be backported to stable kernel trees for the following reasons:
1. **Fixes a real bug that causes filesystem corruption**: The commit fixes a bug where deleted b-tree nodes in HFS filesystems are not properly erased, leading to filesystem corruption that is detected by fsck.hfs. The commit message shows clear evidence of filesystem corruption with "Unused node is not erased" errors across multiple nodes (2, 4, 253-256).
2. **Small and contained fix**: The patch is only 1 line of code addition (`hfs_bnode_clear(node, 0, tree->node_size);`), well within the 100-line stable tree limit. The fix is localized to the HFS b-tree node management code and doesn't affect other subsystems.
3. **Obviously correct**: The fix adds a missing step that already exists in the HFS+ implementation. Looking at fs/hfsplus/bnode.c:728-729, the HFS+ code already calls `hfs_bnode_clear()` when deleting b-tree nodes (conditionally based on a volume attribute). The HFS code was missing this critical step entirely.
4. **Tested with concrete results**: The commit message includes before and after test results using xfstests generic/001, showing that the filesystem corruption is resolved after applying the patch. The "after" test shows "The volume untitled appears to be OK" from fsck.hfs.
5. **Data corruption prevention**: Without this fix, HFS filesystems can become corrupted during normal operations that involve b-tree node deletion, potentially leading to data loss. This is a serious issue that affects filesystem integrity.
6. **No architectural changes**: The commit doesn't introduce any new features or architectural changes - it simply adds a missing cleanup step that should have been there all along.
7. **Low regression risk**: The `hfs_bnode_clear()` function being called already exists and is used elsewhere in the HFS code. The fix follows the established pattern from HFS+ and uses existing, tested infrastructure.
The commit meets all the stable kernel rules criteria: it fixes a real bug that causes filesystem corruption, is small and contained, is obviously correct (matches HFS+ implementation), and has been tested to resolve the issue.
fs/hfs/bnode.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/fs/hfs/bnode.c b/fs/hfs/bnode.c index 2039cb6d5f66..219e3b8fd6a8 100644 --- a/fs/hfs/bnode.c +++ b/fs/hfs/bnode.c @@ -586,6 +586,7 @@ void hfs_bnode_put(struct hfs_bnode *node) if (test_bit(HFS_BNODE_DELETED, &node->flags)) { hfs_bnode_unhash(node); spin_unlock(&tree->hash_lock); + hfs_bnode_clear(node, 0, tree->node_size); hfs_bmap_free(node); hfs_bnode_free(node); return;