AOSP: e2fsdroid: Refactor basefs allocation.

This refactors base_fs_alloc_load() to address two issues. First, the
failure cases have been made simpler by factoring out a common helper
for freeing a base_fs_allocator. Second, we no longer return
EXIT_FAILURE, since this is not an errcode_t.

Bug: 145316683
Change-Id: I8b28c684ecf3423b605b550177d7ead4eb2821a4
From AOSP commit: b461ade872a809ab913d7506e9b8ed597d57dc87

diff --git a/contrib/android/basefs_allocator.c b/contrib/android/basefs_allocator.c
index 474cc03..c37df14 100644 (file)
--- a/contrib/android/basefs_allocator.c
+++ b/contrib/android/basefs_allocator.c
@@ -25,6 +25,23 @@ static void fs_free_blocks_range(ext2_filsys fs,
        }
 }
 
+static void basefs_allocator_free(ext2_filsys fs,
+                                 struct base_fs_allocator *allocator)
+{
+       struct basefs_entry *e;
+       struct ext2fs_hashmap_entry *it = NULL;
+       struct ext2fs_hashmap *entries = allocator->entries;
+
+       if (entries) {
+               while ((e = ext2fs_hashmap_iter_in_order(entries, &it))) {
+                       fs_free_blocks_range(fs, &e->blocks);
+                       delete_block_ranges(&e->blocks);
+               }
+               ext2fs_hashmap_free(entries);
+       }
+       free(allocator);
+}
+
 static void fs_reserve_blocks_range(ext2_filsys fs,
                                    struct block_range_list *list)
 {
@@ -36,41 +53,58 @@ static void fs_reserve_blocks_range(ext2_filsys fs,
        }
 }
 
-errcode_t base_fs_alloc_load(ext2_filsys fs, const char *file,
-                            const char *mountpoint)
+/*
+ * For each file in the base FS map, ensure that its blocks are reserved in
+ * the actual block map. This prevents libext2fs from allocating them for
+ * general purpose use, and ensures that if the file needs data blocks, they
+ * can be re-acquired exclusively for that file.
+ */
+static void fs_reserve_blocks(ext2_filsys fs,
+                             struct base_fs_allocator *allocator)
 {
-       errcode_t retval;
        struct basefs_entry *e;
        struct ext2fs_hashmap_entry *it = NULL;
+       struct ext2fs_hashmap *entries = allocator->entries;
+
+       while ((e = ext2fs_hashmap_iter_in_order(entries, &it)))
+               fs_reserve_blocks_range(fs, &e->blocks);
+}
+
+errcode_t base_fs_alloc_load(ext2_filsys fs, const char *file,
+                            const char *mountpoint)
+{
+       errcode_t retval = 0;
        struct base_fs_allocator *allocator;
-       struct ext2fs_hashmap *entries = basefs_parse(file, mountpoint);
-       if (!entries)
-               return -1;
 
-       allocator = malloc(sizeof(*allocator));
-       if (!allocator)
-               goto err_alloc;
+       allocator = calloc(1, sizeof(*allocator));
+       if (!allocator) {
+               retval = ENOMEM;
+               goto out;
+       }
 
        retval = ext2fs_read_bitmaps(fs);
        if (retval)
-               goto err_bitmap;
-       while ((e = ext2fs_hashmap_iter_in_order(entries, &it)))
-               fs_reserve_blocks_range(fs, &e->blocks);
+               goto err_alloc;
 
        allocator->cur_entry = NULL;
-       allocator->entries = entries;
+       allocator->entries = basefs_parse(file, mountpoint);
+       if (!allocator->entries) {
+               retval = EIO;
+               goto err_alloc;
+       }
+
+       fs_reserve_blocks(fs, allocator);
 
        /* Override the default allocator */
        fs->get_alloc_block2 = basefs_block_allocator;
        fs->priv_data = allocator;
 
-       return 0;
+       goto out;
 
-err_bitmap:
-       free(allocator);
 err_alloc:
-       ext2fs_hashmap_free(entries);
-       return EXIT_FAILURE;
+       basefs_allocator_free(fs, allocator);
+out:
+       return retval;
 }
 
 static errcode_t basefs_block_allocator(ext2_filsys fs, blk64_t goal,
@@ -94,19 +128,9 @@ static errcode_t basefs_block_allocator(ext2_filsys fs, blk64_t goal,
 
 void base_fs_alloc_cleanup(ext2_filsys fs)
 {
-       struct basefs_entry *e;
-       struct ext2fs_hashmap_entry *it = NULL;
-       struct base_fs_allocator *allocator = fs->priv_data;
-
-       while ((e = ext2fs_hashmap_iter_in_order(allocator->entries, &it))) {
-               fs_free_blocks_range(fs, &e->blocks);
-               delete_block_ranges(&e->blocks);
-       }
-
+       basefs_allocator_free(fs, fs->priv_data);
        fs->priv_data = NULL;
        fs->get_alloc_block2 = NULL;
-       ext2fs_hashmap_free(allocator->entries);
-       free(allocator);
 }
 
 errcode_t base_fs_alloc_set_target(ext2_filsys fs, const char *target_path,