Added proper handling of orphans

Unfortunately, threading all dir blocks in a linked-list did
not come without problems.

While it's possible to atomically add a dir to the linked list
(by adding the new dir into the linked-list position immediately
after it's parent, requiring only one atomic update to the parent
block), it is not easy to make sure the linked-list is in a state
that always allows atomic removal of dirs.

The simple solution is to allow this non-atomic removal, with an
additional step to remove any orphans that could have been created
by a power-loss. This deorphan step is only run if the normal
allocator has failed.
This commit is contained in:
Christopher Haster
2017-04-01 12:23:15 -05:00
parent 8a674524fc
commit a3734eeb34
3 changed files with 216 additions and 40 deletions

View File

@@ -123,5 +123,62 @@ tests/test.py << TEST
lfs_unmount(&lfs) => 0;
TEST
echo "--- Directory deletion ---"
tests/test.py << TEST
lfs_mount(&lfs, &config) => 0;
lfs_remove(&lfs, "potato") => LFS_ERROR_INVALID;
lfs_remove(&lfs, "potato/sweet") => 0;
lfs_remove(&lfs, "potato/baked") => 0;
lfs_remove(&lfs, "potato/fried") => 0;
lfs_dir_open(&lfs, &dir[0], "potato") => 0;
lfs_dir_read(&lfs, &dir[0], &info) => 1;
strcmp(info.name, ".") => 0;
info.type => LFS_TYPE_DIR;
lfs_dir_read(&lfs, &dir[0], &info) => 1;
strcmp(info.name, "..") => 0;
info.type => LFS_TYPE_DIR;
lfs_dir_read(&lfs, &dir[0], &info) => 0;
lfs_dir_close(&lfs, &dir[0]) => 0;
lfs_remove(&lfs, "potato") => 0;
lfs_dir_open(&lfs, &dir[0], "/") => 0;
lfs_dir_read(&lfs, &dir[0], &info) => 1;
strcmp(info.name, ".") => 0;
info.type => LFS_TYPE_DIR;
lfs_dir_read(&lfs, &dir[0], &info) => 1;
strcmp(info.name, "..") => 0;
info.type => LFS_TYPE_DIR;
lfs_dir_read(&lfs, &dir[0], &info) => 1;
strcmp(info.name, "burito") => 0;
info.type => LFS_TYPE_REG;
lfs_dir_read(&lfs, &dir[0], &info) => 1;
strcmp(info.name, "cactus") => 0;
info.type => LFS_TYPE_DIR;
lfs_dir_read(&lfs, &dir[0], &info) => 0;
lfs_dir_close(&lfs, &dir[0]) => 0;
lfs_unmount(&lfs) => 0;
TEST
tests/test.py << TEST
lfs_mount(&lfs, &config) => 0;
lfs_dir_open(&lfs, &dir[0], "/") => 0;
lfs_dir_read(&lfs, &dir[0], &info) => 1;
strcmp(info.name, ".") => 0;
info.type => LFS_TYPE_DIR;
lfs_dir_read(&lfs, &dir[0], &info) => 1;
strcmp(info.name, "..") => 0;
info.type => LFS_TYPE_DIR;
lfs_dir_read(&lfs, &dir[0], &info) => 1;
strcmp(info.name, "burito") => 0;
info.type => LFS_TYPE_REG;
lfs_dir_read(&lfs, &dir[0], &info) => 1;
strcmp(info.name, "cactus") => 0;
info.type => LFS_TYPE_DIR;
lfs_dir_read(&lfs, &dir[0], &info) => 0;
lfs_dir_close(&lfs, &dir[0]) => 0;
lfs_unmount(&lfs) => 0;
TEST
echo "--- Results ---"
tests/stats.py