tests/zfs-tests/tests/functional/procfs/procfs_list_basic.ksh

   1 #!/bin/ksh -p
   2 #
   3 # CDDL HEADER START
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   5 # The contents of this file are subject to the terms of the
   6 # Common Development and Distribution License (the "License").
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  11 # See the License for the specific language governing permissions
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  16 # If applicable, add the following below this CDDL HEADER, with the
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  21 #
  22
  23 #
  24 # Copyright (c) 2018 by Delphix. All rights reserved.
  25 #
  26
  27 . $STF_SUITE/include/libtest.shlib
  28
  29 #
  30 # DESCRIPTION:
  31 # Test that we can read from and write to a file in procfs whose contents is
  32 # backed by a linked list.
  33 #
  34 # STRATEGY:
  35 # 1. Take some snapshots of a filesystem, which will cause some messages to be
  36 #    written to the zfs dbgmsgs.
  37 # 2. Read the dbgmsgs via procfs and verify that the expected messages are
  38 #    present.
  39 # 3. Write to the dbgmsgs file to clear the messages.
  40 # 4. Read the dbgmsgs again, and make sure the messages are no longer present.
  41 #
  42
  43 function cleanup
  44 {
  45         datasetexists $FS && log_must zfs destroy -r $FS
  46 }
  47
  48 function count_snap_cmds
  49 {
  50         typeset expected_count=$1
  51         count=$(grep "command: zfs snapshot $FS@testsnapshot" | wc -l)
  52         log_must eval "[[ $count -eq $expected_count ]]"
  53 }
  54
  55 typeset -r ZFS_DBGMSG=/proc/spl/kstat/zfs/dbgmsg
  56 typeset -r FS=$TESTPOOL/fs
  57 typeset snap_msgs
  58
  59 log_onexit cleanup
  60
  61 # Clear out old messages
  62 echo 0 >$ZFS_DBGMSG || log_fail "failed to write to $ZFS_DBGMSG"
  63
  64 log_must zfs create $FS
  65 for i in {1..20}; do
  66         log_must zfs snapshot "$FS@testsnapshot$i"
  67 done
  68 log_must zpool sync $TESTPOOL
  69
  70 #
  71 # Read the debug message file in small chunks to make sure that the read is
  72 # split up into multiple syscalls. This tests that when a syscall begins we
  73 # correctly pick up in the list of messages where the previous syscall left
  74 # off. The size of the read can affect how many bytes the seq_file code has
  75 # left in its internal buffer, which in turn can affect the relative pos that
  76 # the seq_file code picks up at when the next read starts. Try a few
  77 # different size reads to make sure we can handle each case.
  78 #
  79 # Check that the file has the right contents by grepping for some of the
  80 # messages that we expect to be present.
  81 #
  82 for chunk_sz in {1,64,256,1024,4096}; do
  83         dd if=$ZFS_DBGMSG bs=$chunk_sz | count_snap_cmds 20
  84 done
  85
  86 # Clear out old messages and check that they really are gone
  87 echo 0 >$ZFS_DBGMSG || log_fail "failed to write to $ZFS_DBGMSG"
  88 cat $ZFS_DBGMSG | count_snap_cmds 0
  89 #
  90 # Even though we don't expect any messages in the file, reading should still
  91 # succeed.
  92 #
  93 log_must cat $ZFS_DBGMSG
  94
  95 log_pass "Basic reading/writing of procfs file backed by linked list successful"