2 # SPDX-License-Identifier: GPL-2.0
3 # Copyright (C) 2015 SUSE Linux Products GmbH. All Rights Reserved.
7 # This test is motivated by an fsync issue discovered in btrfs.
8 # The steps to trigger the issue were:
10 # 1) remove an hard link from an inode with a large number of hard links;
11 # 2) add a new hard link;
12 # 3) add another hard link with the same name as the one removed in step 1;
15 # These steps made the btrfs fsync log replay fail (with the -EOVERFLOW error),
16 # making the filesystem unmountable, requiring the use of btrfs-zero-log (it
17 # wipes the fsync log) in order to make the filesystem mountable again (but
18 # losing some data/metadata).
20 # The btrfs issue was fixed by the following linux kernel patches:
22 # Btrfs: fix fsync when extend references are added to an inode
23 # Btrfs: fix fsync log replay for inodes with a mix of regular refs and extrefs
25 # This issue was present in btrfs since the extrefs (extend references)
26 # feature was added (2012).
29 seqres=$RESULT_DIR/$seq
30 echo "QA output created by $seq"
34 status=1 # failure is the default!
40 trap "_cleanup; exit \$status" 0 1 2 3 15
42 # get standard environment, filters and checks
47 # real QA test starts here
51 _require_dm_target flakey
55 # If the test filesystem is btrfs, make sure we create a filesystem with
56 # the extend references (extrefs) feature enabled (it's enabled by default
57 # in recent versions of btrfs-progs).
58 if [ "$FSTYP" = "btrfs" ]; then
59 _scratch_mkfs "-O extref" >> $seqres.full 2>&1
61 _scratch_mkfs >> $seqres.full 2>&1
64 _require_metadata_journaling $SCRATCH_DEV
68 # Create a test file with 3001 hard links. This number is large enough to
69 # make btrfs start using extrefs at some point even if the fs has the maximum
70 # possible leaf/node size (64Kb).
71 echo "hello world" > $SCRATCH_MNT/foo
72 for i in `seq 1 3000`; do
73 ln $SCRATCH_MNT/foo $SCRATCH_MNT/foo_link_`printf "%04d" $i`
76 # Make sure all metadata and data are durably persisted.
79 # Now remove one link, add a new one with a new name, add another new one with
80 # the same name as the one we just removed and fsync the inode.
81 rm -f $SCRATCH_MNT/foo_link_0001
82 ln $SCRATCH_MNT/foo $SCRATCH_MNT/foo_link_3001
83 ln $SCRATCH_MNT/foo $SCRATCH_MNT/foo_link_0001
84 rm -f $SCRATCH_MNT/foo_link_0002
85 ln $SCRATCH_MNT/foo $SCRATCH_MNT/foo_link_3002
86 ln $SCRATCH_MNT/foo $SCRATCH_MNT/foo_link_3003
87 $XFS_IO_PROG -c "fsync" $SCRATCH_MNT/foo
89 _flakey_drop_and_remount
91 # Check that the number of hard links is correct, we are able to remove all
92 # the hard links and read the file's data. This is just to verify we don't
93 # get stale file handle errors (due to dangling directory index entries that
94 # point to inodes that no longer exist).
95 echo "Link count: $(stat -c %h $SCRATCH_MNT/foo)"
96 [ -f $SCRATCH_MNT/foo ] || echo "Link foo is missing"
97 for ((i = 1; i <= 3003; i++)); do
98 name=foo_link_`printf "%04d" $i`
100 [ -f $SCRATCH_MNT/$name ] && echo "Link $name found"
102 [ -f $SCRATCH_MNT/$name ] || echo "Link $name is missing"
105 rm -f $SCRATCH_MNT/foo_link_*
107 rm -f $SCRATCH_MNT/foo