[thin_repair, cache_repair] Check input file exists earlier

and zero superblock if we fail part way through a repair.

bz1499781

caching/cache_repair.cc

@@ -2,6 +2,7 @@
 #include <getopt.h>
 #include <libgen.h>
 
+#include "base/file_utils.h"
 #include "base/output_file_requirements.h"
 #include "caching/commands.h"
 #include "caching/metadata.h"
@@ -29,12 +30,17 @@ namespace {
 	}
 
 	int repair(string const &old_path, string const &new_path) {
+		bool metadata_touched = false;
 		try {
+			file_utils::check_file_exists(new_path);
+			metadata_touched = true;
 			metadata_dump(open_metadata_for_read(old_path),
 				      output_emitter(new_path),
 				      true);
 
 		} catch (std::exception &e) {
+			if (metadata_touched)
+				file_utils::zero_superblock(new_path);
 			cerr << e.what() << endl;
 			return 1;
 		}
@@ -110,7 +116,7 @@ cache_repair_cmd::run(int argc, char **argv)
 		check_output_file_requirements(*output_path);
 
 	else {
-		cerr << "no output file provided" << endl;
+		cerr << "No output file provided." << endl;
 		usage(cerr);
 		return 1;
 	}

functional-tests/cache-functional-tests.scm

@@ -15,6 +15,7 @@
   (define-tool cache-dump)
   (define-tool cache-restore)
   (define-tool cache-metadata-size)
+  (define-tool cache-repair)
 
   (define-syntax with-cache-xml
     (syntax-rules ()
@@ -35,7 +36,8 @@
     (syntax-rules ()
       ((_ (md) b1 b2 ...)
        (with-temp-file-sized ((md "cache.bin" (to-bytes (meg 4))))
-         b1 b2 ...))))
+         (system (fmt #f "dd if=/usr/bin/ls of=" md " bs=4096 > /dev/null 2>&1"))
+           b1 b2 ...))))
 
   (define-syntax with-empty-metadata
     (syntax-rules ()
@@ -180,7 +182,7 @@
     "the input file can't be found"
     (with-empty-metadata (md)
       (run-fail-rcv (_ stderr) (cache-restore "-i no-such-file -o" md)
-        (assert-superblock-untouched md)
+        (assert-superblock-all-zeroes md)
         (assert-starts-with "Couldn't stat file" stderr))))
 
   (define-scenario (cache-restore garbage-input-file)
@@ -188,7 +190,7 @@
     (with-empty-metadata (md)
       (with-temp-file-sized ((xml "cache.xml" 4096))
         (run-fail-rcv (_ stderr) (cache-restore "-i" xml "-o" md)
-          (assert-superblock-untouched md)))))
+          (assert-superblock-all-zeroes md)))))
 
   (define-scenario (cache-restore missing-output-file)
     "the output file can't be found"
@@ -354,4 +356,28 @@
     (run-ok-rcv (stdout stderr) (cache-metadata-size "--nr-blocks 67108864")
       (assert-equal "3678208 sectors" stdout)
       (assert-eof stderr)))
+
+  ;;;-----------------------------------------------------------
+  ;;; cache_repair scenarios
+  ;;;-----------------------------------------------------------
+  (define-scenario (cache-repair missing-input-file)
+    "the input file can't be found"
+    (with-empty-metadata (md)
+      (run-fail-rcv (_ stderr) (cache-repair "-i no-such-file -o" md)
+        (assert-superblock-all-zeroes md)
+        (assert-starts-with "Couldn't stat path" stderr))))
+
+  (define-scenario (cache-repair garbage-input-file)
+    "the input file is just zeroes"
+    (with-empty-metadata (md1)
+      (with-corrupt-metadata (md2)
+        (run-fail-rcv (_ stderr) (cache-repair "-i" md1 "-o" md2)
+          (assert-superblock-all-zeroes md2)))))
+
+  (define-scenario (cache-repair missing-output-file)
+    "the output file can't be found"
+    (with-cache-xml (xml)
+      (run-fail-rcv (_ stderr) (cache-repair "-i" xml)
+        (assert-starts-with "No output file provided." stderr))))
+
 )

functional-tests/era-functional-tests.scm

@@ -153,7 +153,7 @@
     "the input file can't be found"
     (with-empty-metadata (md)
       (run-fail-rcv (_ stderr) (era-restore "-i no-such-file -o" md)
-        (assert-superblock-untouched md)
+        (assert-superblock-all-zeroes md)
         (assert-starts-with "Couldn't stat file" stderr))))
 
   (define-scenario (era-restore garbage-input-file)
@@ -161,7 +161,7 @@
     (with-empty-metadata (md)
       (with-temp-file-sized ((xml "era.xml" 4096))
         (run-fail-rcv (_ stderr) (era-restore "-i " xml "-o" md)
-          (assert-superblock-untouched md)))))
+          (assert-superblock-all-zeroes md)))))
 
   (define-scenario (era-restore output-unspecified)
     "Fails if no metadata dev specified"

functional-tests/functional-tests.scm

@@ -21,7 +21,7 @@
     assert-eof
     assert-starts-with
     assert-matches
-    assert-superblock-untouched
+    assert-superblock-all-zeroes
     assert-member?
     assert-raises-thunk
     assert-raises
@@ -259,7 +259,7 @@
               (loop (+ i 1))
               #f)))))
 
-  (define (assert-superblock-untouched md)
+  (define (assert-superblock-all-zeroes md)
     (with-bcache (cache md 1)
       (with-block (b cache 0 (get-flags))
         (unless (all-zeroes? (block-data b) 4096)

functional-tests/thin-functional-tests.scm

@@ -37,10 +37,12 @@
            b1 b2 ...)))))
 
   ;;; It would be nice if the metadata was at least similar to valid data.
+  ;;; Here I'm just using the start of the ls binary as 'random' data.
   (define-syntax with-corrupt-metadata
     (syntax-rules ()
       ((_ (md) b1 b2 ...)
        (with-temp-file-sized ((md "thin.bin" (meg 4)))
+         (system (fmt #f "dd if=/usr/bin/ls of=" md " bs=4096 > /dev/null 2>&1"))
          b1 b2 ...))))
 
   (define-syntax with-empty-metadata
@@ -167,7 +169,7 @@
     "the input file can't be found"
     (with-empty-metadata (md)
       (run-fail-rcv (_ stderr) (thin-restore "-i no-such-file -o" md)
-        (assert-superblock-untouched md)
+        (assert-superblock-all-zeroes md)
         (assert-starts-with "Couldn't stat file" stderr))))
 
   (define-scenario (thin-restore garbage-input-file)
@@ -175,7 +177,7 @@
     (with-empty-metadata (md)
       (with-temp-file-sized ((xml "thin.xml" 4096))
         (run-fail-rcv (_ stderr) (thin-restore "-i " xml "-o" md)
-          (assert-superblock-untouched md)))))
+          (assert-superblock-all-zeroes md)))))
 
   (define-scenario (thin-restore missing-output-file)
     "the output file can't be found"
@@ -333,4 +335,25 @@
       (with-empty-metadata (md)
         (run-fail-rcv (_ stderr) (thin-repair "-i" xml "-o" md)
           #t))))
+
+  (define-scenario (thin-repair missing-input-file)
+    "the input file can't be found"
+    (with-empty-metadata (md)
+      (run-fail-rcv (_ stderr) (thin-repair "-i no-such-file -o" md)
+        (assert-superblock-all-zeroes md)
+        (assert-starts-with "Couldn't stat file" stderr))))
+
+  (define-scenario (thin-repair garbage-input-file)
+    "the input file is just zeroes"
+    (with-empty-metadata (md1)
+      (with-corrupt-metadata (md2)
+        (run-fail-rcv (_ stderr) (thin-repair "-i " md1 "-o" md2)
+          (assert-superblock-all-zeroes md2)))))
+
+  (define-scenario (thin-repair missing-output-file)
+    "the output file can't be found"
+    (with-thin-xml (xml)
+      (run-fail-rcv (_ stderr) (thin-repair "-i " xml)
+        (assert-starts-with "No output file provided." stderr))))
+
   )

thin-provisioning/thin_repair.cc

@@ -2,6 +2,7 @@
 #include <getopt.h>
 #include <libgen.h>
 
+#include "base/file_utils.h"
 #include "base/output_file_requirements.h"
 #include "persistent-data/file_utils.h"
 #include "thin-provisioning/commands.h"
@@ -17,15 +18,20 @@ using namespace thin_provisioning;
 
 namespace {
 	int repair(string const &old_path, string const &new_path) {
+		bool metadata_touched = false;
 		try {
 			// block size gets updated by the restorer
 			block_manager<>::ptr new_bm = open_bm(new_path, block_manager<>::READ_WRITE);
+			file_utils::check_file_exists(old_path);
+			metadata_touched = true;
 			metadata::ptr new_md(new metadata(new_bm, metadata::CREATE, 128, 0));
 			emitter::ptr e = create_restore_emitter(new_md);
 			block_manager<>::ptr old_bm = open_bm(old_path, block_manager<>::READ_ONLY);
 			metadata_repair(old_bm, e);
 
 		} catch (std::exception &e) {
+			if (metadata_touched)
+				file_utils::zero_superblock(new_path);
 			cerr << e.what() << endl;
 			return 1;
 		}
@@ -101,7 +107,7 @@ thin_repair_cmd::run(int argc, char **argv)
 		check_output_file_requirements(*output_path);
 
 	else {
-		cerr << "no output file provided" << endl;
+		cerr << "No output file provided." << endl;
 		usage(cerr);
 		return 1;
 	}