Fixed bug where globals were poisoning move commits

The issue lies in the reuse of the id field for globals. Before globals,
the only tags with a non-null (0x3ff) id field were names, structs, and
other file-specific metadata. But globals are also using this field for
the indirect delete, since otherwise the globals structure would be very
unaligned (74-bits long).

To make matters worse, the id field for globals contains the delta used
to reconstruct the globals at mount time. Which means the id field could
take on very absurd values and break the dir fetch logic if we're not
careful.

Solution is to use the scope portion of the type field where necessary,
although unforunately this does add some code cost.

lfs.c

@@ -664,6 +664,13 @@ static int lfs_commit_movescan(lfs_t *lfs, void *p, lfs_mattr_t attr) {
         return 0;
     }
 
+    // TODO AHHHH, scopes, what about user scope above?
+    if (lfs_tag_scope(attr.tag) == LFS_SCOPE_FS ||
+            lfs_tag_scope(attr.tag) == LFS_SCOPE_DIR) {
+        // ignore non-matching ids
+        return 0;
+    }
+
     if (lfs_tag_id(attr.tag) != move->id.from) {
         // ignore non-matching ids
         return 0;
@@ -1023,6 +1030,9 @@ static int lfs_dir_compact(lfs_t *lfs, lfs_mdir_t *dir, lfs_mattrlist_t *list,
 
     // There's nothing special about our global delta, so feed it back
     // into the global global delta
+    // TODO IMMENSE HMM globals get bleed into from above, need to be fixed after commits due to potential moves
+    lfs_globals_t gtemp = dir->globals; // TODO hmm, why did we have different variables then?
+
     lfs->diff = lfs_globals_xor(&lfs->diff, &dir->globals);
     dir->globals = (lfs_globals_t){0};
 
@@ -1196,6 +1206,8 @@ relocate:
         lfs->diff = (lfs_globals_t){0};
     }
 
+    lfs->globals = lfs_globals_xor(&lfs->globals, &gtemp); // TODO hmm, why did we have different variables then?
+
     return 0;
 }
 
@@ -1244,6 +1256,8 @@ static int lfs_dir_commit(lfs_t *lfs, lfs_mdir_t *dir, lfs_mattrlist_t *list) {
         // successful commit, lets update dir
         dir->off = commit.off;
         dir->etag = commit.ptag;
+//        // TODO hm
+//        dir->globals = lfs_globals_xor(&dir->globals, &lfs->diff);
         lfs->globals = lfs_globals_xor(&lfs->globals, &lfs->diff);
         lfs->diff = (lfs_globals_t){0};
         break;
@@ -2954,6 +2968,10 @@ int lfs_rename(lfs_t *lfs, const char *oldpath, const char *newpath) {
             return res;
         }
 
+        // TODO test for global state stealing?
+        // steal global state
+        lfs->globals = lfs_globals_xor(&lfs->globals, &prevdir.globals);
+
         LFS_ASSERT(res); // must have pred
         newcwd.tail[0] = prevdir.tail[0];
         newcwd.tail[1] = prevdir.tail[1];

lfs.h

@@ -129,7 +129,7 @@ enum lfs_type {
     // internal sources
     LFS_FROM_REGION     = 0x000,
     LFS_FROM_DISK       = 0x200,
-    LFS_FROM_MOVE       = 0x0ff,
+    LFS_FROM_MOVE       = 0x03f,
 };
 
 // File open flags

tests/test_move.sh

@@ -109,7 +109,7 @@ tests/test.py << TEST
 TEST
 
 echo "--- Move file after corrupt ---"
-tests/test.py -s << TEST
+tests/test.py << TEST
     lfs_mount(&lfs, &cfg) => 0;
     lfs_rename(&lfs, "c/hello", "d/hello") => 0;
     lfs_unmount(&lfs) => 0;
@@ -166,7 +166,7 @@ tests/test.py << TEST
     lfs_rename(&lfs, "b/hi", "c/hi") => 0;
     lfs_unmount(&lfs) => 0;
 TEST
-rm -v blocks/7
+truncate -s-11 blocks/7
 tests/test.py << TEST
     lfs_mount(&lfs, &cfg) => 0;
     lfs_dir_open(&lfs, &dir[0], "b") => 0;
@@ -182,8 +182,6 @@ tests/test.py << TEST
     lfs_dir_read(&lfs, &dir[0], &info) => 1;
     strcmp(info.name, "..") => 0;
     lfs_dir_read(&lfs, &dir[0], &info) => 1;
-    strcmp(info.name, "hello") => 0;
-    lfs_dir_read(&lfs, &dir[0], &info) => 1;
     strcmp(info.name, "hi") => 0;
     lfs_dir_read(&lfs, &dir[0], &info) => 0;
     lfs_unmount(&lfs) => 0;
@@ -195,8 +193,8 @@ tests/test.py << TEST
     lfs_rename(&lfs, "c/hi", "d/hi") => 0;
     lfs_unmount(&lfs) => 0;
 TEST
-rm -v blocks/9
-rm -v blocks/a
+truncate -s-11 blocks/9
+truncate -s-11 blocks/b
 tests/test.py << TEST
     lfs_mount(&lfs, &cfg) => 0;
     lfs_dir_open(&lfs, &dir[0], "c") => 0;
@@ -205,9 +203,33 @@ tests/test.py << TEST
     lfs_dir_read(&lfs, &dir[0], &info) => 1;
     strcmp(info.name, "..") => 0;
     lfs_dir_read(&lfs, &dir[0], &info) => 1;
+    strcmp(info.name, "hi") => 0;
+    lfs_dir_read(&lfs, &dir[0], &info) => 0;
+    lfs_dir_close(&lfs, &dir[0]) => 0;
+    lfs_dir_open(&lfs, &dir[0], "d") => 0;
+    lfs_dir_read(&lfs, &dir[0], &info) => 1;
+    strcmp(info.name, ".") => 0;
+    lfs_dir_read(&lfs, &dir[0], &info) => 1;
+    strcmp(info.name, "..") => 0;
+    lfs_dir_read(&lfs, &dir[0], &info) => 1;
     strcmp(info.name, "hello") => 0;
+    lfs_dir_read(&lfs, &dir[0], &info) => 0;
+    lfs_unmount(&lfs) => 0;
+TEST
+
+echo "--- Move dir after corrupt ---"
+tests/test.py << TEST
+    lfs_mount(&lfs, &cfg) => 0;
+    lfs_rename(&lfs, "c/hi", "d/hi") => 0;
+    lfs_unmount(&lfs) => 0;
+TEST
+tests/test.py << TEST
+    lfs_mount(&lfs, &cfg) => 0;
+    lfs_dir_open(&lfs, &dir[0], "c") => 0;
     lfs_dir_read(&lfs, &dir[0], &info) => 1;
-    strcmp(info.name, "hi") => 0;
+    strcmp(info.name, ".") => 0;
+    lfs_dir_read(&lfs, &dir[0], &info) => 1;
+    strcmp(info.name, "..") => 0;
     lfs_dir_read(&lfs, &dir[0], &info) => 0;
     lfs_dir_close(&lfs, &dir[0]) => 0;
     lfs_dir_open(&lfs, &dir[0], "d") => 0;
@@ -215,6 +237,10 @@ tests/test.py << TEST
     strcmp(info.name, ".") => 0;
     lfs_dir_read(&lfs, &dir[0], &info) => 1;
     strcmp(info.name, "..") => 0;
+    lfs_dir_read(&lfs, &dir[0], &info) => 1;
+    strcmp(info.name, "hello") => 0;
+    lfs_dir_read(&lfs, &dir[0], &info) => 1;
+    strcmp(info.name, "hi") => 0;
     lfs_dir_read(&lfs, &dir[0], &info) => 0;
     lfs_unmount(&lfs) => 0;
 TEST
@@ -225,9 +251,9 @@ tests/test.py << TEST
 
     lfs_dir_open(&lfs, &dir[0], "a/hi") => LFS_ERR_NOENT;
     lfs_dir_open(&lfs, &dir[0], "b/hi") => LFS_ERR_NOENT;
-    lfs_dir_open(&lfs, &dir[0], "d/hi") => LFS_ERR_NOENT;
+    lfs_dir_open(&lfs, &dir[0], "c/hi") => LFS_ERR_NOENT;
 
-    lfs_dir_open(&lfs, &dir[0], "c/hi") => 0;
+    lfs_dir_open(&lfs, &dir[0], "d/hi") => 0;
     lfs_dir_read(&lfs, &dir[0], &info) => 1;
     strcmp(info.name, ".") => 0;
     lfs_dir_read(&lfs, &dir[0], &info) => 1;
@@ -243,9 +269,9 @@ tests/test.py << TEST
 
     lfs_dir_open(&lfs, &dir[0], "a/hello") => LFS_ERR_NOENT;
     lfs_dir_open(&lfs, &dir[0], "b/hello") => LFS_ERR_NOENT;
-    lfs_dir_open(&lfs, &dir[0], "d/hello") => LFS_ERR_NOENT;
+    lfs_dir_open(&lfs, &dir[0], "c/hello") => LFS_ERR_NOENT;
 
-    lfs_file_open(&lfs, &file[0], "c/hello", LFS_O_RDONLY) => 0;
+    lfs_file_open(&lfs, &file[0], "d/hello", LFS_O_RDONLY) => 0;
     lfs_file_read(&lfs, &file[0], buffer, 5) => 5;
     memcmp(buffer, "hola\n", 5) => 0;
     lfs_file_read(&lfs, &file[0], buffer, 8) => 8;