I was looking how fsfs upgrade code works and found particular fsfs7
log-addressing repository corruption bug:
0. Repository has 999 revisions.
1. Client begins committing some data to fsfs v6 repository through Apache
2. Apache web server opens svn_fs_t, reads format file. At this point
repository has format 6 and uses physical (classic) addressing.
3. Client changes txn content
4. Before committing change, admin upgrades this repository to fsfs7. FSFS
upgrade code marks that log-addressing will be available from next shard,
i.e. from revision 1000.
5. Apache web server starting committing txn: obtaining write-lock and writes
protorev for r1000. Since svn_fs_t instance was cached for connection so
it didn't know that revision 1000 should be log addressing and writes
physical addressing revision without any error (!)
Commit succeeded, but repository is unreadable.
I'm attaching patch with test reproducing this issue. The commit may
fail in maintainer mode because txn will be verified before commit.
--
Ivan Zhakov
Index: subversion/tests/libsvn_fs/fs-test.c
===================================================================
--- subversion/tests/libsvn_fs/fs-test.c (revision 1627774)
+++ subversion/tests/libsvn_fs/fs-test.c (working copy)
@@ -5403,7 +5403,57 @@
#endif
}
+static svn_error_t *
+upgrade_while_committing(const svn_test_opts_t *opts,
+ apr_pool_t *pool)
+{
+ svn_fs_t *fs;
+ svn_revnum_t head_rev = 0;
+ svn_fs_root_t *root;
+ svn_fs_txn_t *txn;
+ const char *fs_path;
+ apr_hash_t *fs_config = apr_hash_make(pool);
+ /* Bail (with success) on known-untestable scenarios */
+ if (strcmp(opts->fs_type, "fsfs") != 0)
+ return svn_error_create(SVN_ERR_TEST_SKIPPED, NULL,
+ "this will test FSFS repositories only");
+
+ if (opts->server_minor_version && (opts->server_minor_version < 6))
+ return svn_error_create(SVN_ERR_TEST_SKIPPED, NULL,
+ "pre-1.6 SVN doesn't support FSFS packing");
+
+ /* Create test repository with greek tree. */
+ fs_path = "test-upgrade-while-committing";
+
+ svn_hash_sets(fs_config, SVN_FS_CONFIG_COMPATIBLE_VERSION, "1.7");
+ svn_hash_sets(fs_config, SVN_FS_CONFIG_FSFS_SHARD_SIZE, "2");
+ SVN_ERR(svn_test__create_fs2(&fs, fs_path, opts, fs_config, pool));
+
+ SVN_ERR(svn_fs_open(&fs, fs_path, NULL, pool));
+ SVN_ERR(svn_fs_begin_txn(&txn, fs, head_rev, pool));
+ SVN_ERR(svn_fs_txn_root(&root, txn, pool));
+ SVN_ERR(svn_test__create_greek_tree(root, pool));
+ SVN_ERR(test_commit_txn(&head_rev, txn, NULL, pool));
+
+ /* Upgrade filesystem, but keep existing svn_fs_t object. */
+ SVN_ERR(svn_fs_upgrade(fs_path, pool));
+
+ /* Create txn with changes. */
+ SVN_ERR(svn_fs_begin_txn(&txn, fs, head_rev, pool));
+ SVN_ERR(svn_fs_txn_root(&root, txn, pool));
+ SVN_ERR(svn_fs_make_dir(root, "/foo", pool));
+
+ /* Commit txn. */
+ SVN_ERR(test_commit_txn(&head_rev, txn, NULL, pool));
+
+ /* Verify filesystem content. */
+ SVN_ERR(svn_fs_verify(fs_path, NULL, 0, SVN_INVALID_REVNUM, NULL, NULL,
+ NULL, NULL, pool));
+
+ return SVN_NO_ERROR;
+}
+
/* ------------------------------------------------------------------------ */
/* The test table. */
@@ -5501,6 +5551,8 @@
SVN_TEST_OPTS_WIMP(reopen_modify,
"test reopen and modify txn",
"txn_dir_cache fail in FSFS"),
+ SVN_TEST_OPTS_PASS(upgrade_while_committing,
+ "upgrade while committing"),
SVN_TEST_NULL
};
