166 lines
5.1 KiB
Plaintext
166 lines
5.1 KiB
Plaintext
=================================================================
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Test Suite for Bind Mount and Shared Subtree Features in the VFS:
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=================================================================
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Author: Avantika Mathur
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Date: September 16, 2005
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Last update: March 18th, 2008 (by Matt Helsley)
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About:
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------
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These tests exercise the Linux Kernel's bind mount and shared subtree
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capabilities. With it administrators may use clear semantics to manage
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complex mount trees on a system.
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Bind mount simply allows administrators to make a directory appear in
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two places at once -- somewhat like hard links for files:
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# mkdir mnt mnt2
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# mount --bind mnt mnt2
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# touch mnt/a
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# ls mnt2
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a
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Note that bind mounts are not recursive. To get a recursive bind mount
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use --rbind.
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Another limitation of simple bind mounts is they cannot propagate future binds:
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# mkdir mnt mnt2
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# mount --bind mnt mnt2
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# touch mnt/a
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# mkdir mnt/foo
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# ls mnt2
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a foo
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# mkdir sub
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# touch sub/b
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# mount --bind sub /mnt/foo
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# ls mnt/foo
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b
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# ls mnt2/foo
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mnt2/foo appears to be empty because the second bind mount did not propagate
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to mnt2. Shared subtrees allow propagation whereas bind mounts do not.
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To enable full administrator control of propagation there are several kinds of
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subtrees:
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private [default -- this is a "normal" mount]
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shared [propagation goes both ways]
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slave [propagation goes one way]
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unbindable [cannot --bind and hence cannot share]
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For further details on these types of subtrees please see your kernel source's
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Documentation/filesystems/sharedsubtree.txt file.
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Building:
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---------
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Uses GNU Make. In the root directory type:
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make
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Installing:
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-----------
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Type:
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make install
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Cleaning:
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---------
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Type:
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make clean
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Running:
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--------
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run LTPROOT/testscripts/test_fs_bind.sh
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Testcases:
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----------
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There are multiple testcases testing in each of the following categories,
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testing functionality of different types of mounts, different combinations,
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etc:
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-- bind
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-- rbind
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-- move
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-- regression tests
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-- clone namespace (currently not run)
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Directory Structure:
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--------------------
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In the root directory of the suite there are scripts to execute the whole test suite. Logged results are stored in LTPROOT/results/fs_bind. PASS/FAIL
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indications are passed to the LTP API and logged in the results directory too.
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Basic tests of bind and move mounts are part of the test_fs_bind.sh test
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script itself. These are prerequisites for the more the complicated tests.
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The bind, rbind, and move directories contain tests for bind, rbind, move in
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combination with the various kinds of subtrees. The regression and cloneNS
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directories perform basic regression tests and combine some of the tests with
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mount namespaces respectively.
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The bin directory contains scripts used by each of the testcases for
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common setup, creating, and comparing mounts.
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Running the Test Suite:
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-----------------------
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To run the entire testsuite run:
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test_fs_bind.sh
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Log directories where the results are stored in LTPROOT/results/fs_bind
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Reading the Test Suite Results:
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-------------------------------
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Test suite results are logged, by default, in the LTPROOT/results/fs_bind
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directory. Its structure is:
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fs_bind-\
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|-> errors (stderr of main test suite script itself)
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|-> summary (stdout of main test suite script itself)
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|-move--\
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| |->test01-\ (logs of test01)
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| | |-> log (stdout)
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| | |-> err (stderr)
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| | |-> mtab.before
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| | |-> mtab.after
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| | |-> proc_mounts.before
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| | |-> proc_mounts.after
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| | |-> files.before (files before running)
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| | |-> dirs.before (dirs before running)
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| | |-> files.after (files after running)
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| | \-> dirs.after (dirs after running)
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| |->test02-\
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| | |
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| ... ...
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|-rbind--\
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| |-->
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... ...
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An testXX/err file will only be left for those tests that had errors and
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stderr was non-empty. mounts.*, files.*, and dirs.* files will be left for
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tests that appear to have broken cleanup sections. The test_fs_bind.sh
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script robustly handles cleanup so, unless the tests are run individually, this
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is not an issue that prevents testing from completing successfully nor does it
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interfere with test results.
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These files make it easy to determine what happened during a given test.
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It's easy to see which tests need to be debugged and which do not. It also
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makes it easy to aggregate output or trace sandbox dirtying from test to test.
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Running individual Tests:
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-------------------------
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Currently tests cannot be run individually because there are several important
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LTP environment dependencies. Some of them are documented below:
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LTP test script environment variables:
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LTPROOT
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TCID
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TST_TOTAL
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TST_COUNT
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LTP commands/functions:
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tst_resm
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tst_brkm
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tst_exit
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LTP contents:
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LTPROOT/testcases/bin
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It's important to note that the individual test scripts use the current working
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directory extensively but never exit it. This may allow the tests to be run
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individually once the above LTP environment dependencies are resolved.
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Lastly none of the logging or debugging information will appear in the
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LTPROOT/results/fs_bind directory when tests are invoked individually since
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those are collected by the test_fs_bind.sh script.
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