mirror of
https://github.com/eledio-devices/thirdparty-littlefs.git
synced 2025-10-31 08:42:40 +01:00
Added atomic move using dirty tag in entry type
The "move problem" has been present in littlefs for a while, but I haven't come across a solution worth implementing for various reasons. The problem is simple: how do we move directory entries across directories atomically? Since multiple directory entries are involved, we can't rely entirely on the atomic block updates. It ends up being a bit of a puzzle. To make the problem more complicated, any directory block update can fail due to wear, and cause the directory block to need to be relocated. This happens rarely, but brings a large number of corner cases. --- The solution in this patch is simple: 1. Mark source as "moving" 2. Copy source to destination 3. Remove source If littlefs ever runs into a "moving" entry, that means a power loss occured during a move. Either the destination entry exists or it doesn't. In this case we just search the entire filesystem for the destination entry. This is expensive, however the chance of a power loss during a move is relatively low.
This commit is contained in:
Christopher Haster
236
tests/test_move.sh
Executable file
236
tests/test_move.sh
Executable file
@@ -0,0 +1,236 @@
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#!/bin/bash
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set -eu
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echo "=== Move tests ==="
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rm -rf blocks
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tests/test.py << TEST
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lfs_format(&lfs, &cfg) => 0;
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lfs_mount(&lfs, &cfg) => 0;
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lfs_mkdir(&lfs, "a") => 0;
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lfs_mkdir(&lfs, "b") => 0;
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lfs_mkdir(&lfs, "c") => 0;
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lfs_mkdir(&lfs, "d") => 0;
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lfs_mkdir(&lfs, "a/hi") => 0;
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lfs_mkdir(&lfs, "a/hi/hola") => 0;
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lfs_mkdir(&lfs, "a/hi/bonjour") => 0;
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lfs_mkdir(&lfs, "a/hi/ohayo") => 0;
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lfs_file_open(&lfs, &file[0], "a/hello", LFS_O_CREAT | LFS_O_WRONLY) => 0;
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lfs_file_write(&lfs, &file[0], "hola\n", 5) => 5;
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lfs_file_write(&lfs, &file[0], "bonjour\n", 8) => 8;
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lfs_file_write(&lfs, &file[0], "ohayo\n", 6) => 6;
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lfs_file_close(&lfs, &file[0]) => 0;
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lfs_unmount(&lfs) => 0;
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TEST
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echo "--- Move file ---"
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tests/test.py << TEST
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lfs_mount(&lfs, &cfg) => 0;
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lfs_rename(&lfs, "a/hello", "b/hello") => 0;
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lfs_unmount(&lfs) => 0;
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TEST
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tests/test.py << TEST
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lfs_mount(&lfs, &cfg) => 0;
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lfs_dir_open(&lfs, &dir[0], "a") => 0;
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lfs_dir_read(&lfs, &dir[0], &info) => 1;
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strcmp(info.name, ".") => 0;
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lfs_dir_read(&lfs, &dir[0], &info) => 1;
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strcmp(info.name, "..") => 0;
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lfs_dir_read(&lfs, &dir[0], &info) => 1;
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strcmp(info.name, "hi") => 0;
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lfs_dir_read(&lfs, &dir[0], &info) => 0;
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lfs_dir_close(&lfs, &dir[0]) => 0;
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lfs_dir_open(&lfs, &dir[0], "b") => 0;
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lfs_dir_read(&lfs, &dir[0], &info) => 1;
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strcmp(info.name, ".") => 0;
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lfs_dir_read(&lfs, &dir[0], &info) => 1;
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strcmp(info.name, "..") => 0;
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lfs_dir_read(&lfs, &dir[0], &info) => 1;
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strcmp(info.name, "hello") => 0;
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lfs_dir_read(&lfs, &dir[0], &info) => 0;
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lfs_unmount(&lfs) => 0;
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TEST
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echo "--- Move file corrupt source ---"
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tests/test.py << TEST
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lfs_mount(&lfs, &cfg) => 0;
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lfs_rename(&lfs, "b/hello", "c/hello") => 0;
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lfs_unmount(&lfs) => 0;
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TEST
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rm -v blocks/7
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tests/test.py << TEST
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lfs_mount(&lfs, &cfg) => 0;
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lfs_dir_open(&lfs, &dir[0], "b") => 0;
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lfs_dir_read(&lfs, &dir[0], &info) => 1;
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strcmp(info.name, ".") => 0;
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lfs_dir_read(&lfs, &dir[0], &info) => 1;
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strcmp(info.name, "..") => 0;
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lfs_dir_read(&lfs, &dir[0], &info) => 0;
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lfs_dir_close(&lfs, &dir[0]) => 0;
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lfs_dir_open(&lfs, &dir[0], "c") => 0;
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lfs_dir_read(&lfs, &dir[0], &info) => 1;
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strcmp(info.name, ".") => 0;
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lfs_dir_read(&lfs, &dir[0], &info) => 1;
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strcmp(info.name, "..") => 0;
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lfs_dir_read(&lfs, &dir[0], &info) => 1;
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strcmp(info.name, "hello") => 0;
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lfs_dir_read(&lfs, &dir[0], &info) => 0;
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lfs_unmount(&lfs) => 0;
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TEST
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echo "--- Move file corrupt source and dest ---"
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tests/test.py << TEST
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lfs_mount(&lfs, &cfg) => 0;
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lfs_rename(&lfs, "c/hello", "d/hello") => 0;
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lfs_unmount(&lfs) => 0;
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TEST
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rm -v blocks/8
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rm -v blocks/a
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tests/test.py << TEST
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lfs_mount(&lfs, &cfg) => 0;
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lfs_dir_open(&lfs, &dir[0], "c") => 0;
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lfs_dir_read(&lfs, &dir[0], &info) => 1;
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strcmp(info.name, ".") => 0;
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lfs_dir_read(&lfs, &dir[0], &info) => 1;
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strcmp(info.name, "..") => 0;
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lfs_dir_read(&lfs, &dir[0], &info) => 1;
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strcmp(info.name, "hello") => 0;
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lfs_dir_read(&lfs, &dir[0], &info) => 0;
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lfs_dir_close(&lfs, &dir[0]) => 0;
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lfs_dir_open(&lfs, &dir[0], "d") => 0;
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lfs_dir_read(&lfs, &dir[0], &info) => 1;
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strcmp(info.name, ".") => 0;
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lfs_dir_read(&lfs, &dir[0], &info) => 1;
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strcmp(info.name, "..") => 0;
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lfs_dir_read(&lfs, &dir[0], &info) => 0;
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lfs_unmount(&lfs) => 0;
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TEST
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echo "--- Move dir ---"
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tests/test.py << TEST
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lfs_mount(&lfs, &cfg) => 0;
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lfs_rename(&lfs, "a/hi", "b/hi") => 0;
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lfs_unmount(&lfs) => 0;
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TEST
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tests/test.py << TEST
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lfs_mount(&lfs, &cfg) => 0;
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lfs_dir_open(&lfs, &dir[0], "a") => 0;
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lfs_dir_read(&lfs, &dir[0], &info) => 1;
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strcmp(info.name, ".") => 0;
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lfs_dir_read(&lfs, &dir[0], &info) => 1;
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strcmp(info.name, "..") => 0;
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lfs_dir_read(&lfs, &dir[0], &info) => 0;
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lfs_dir_close(&lfs, &dir[0]) => 0;
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lfs_dir_open(&lfs, &dir[0], "b") => 0;
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lfs_dir_read(&lfs, &dir[0], &info) => 1;
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strcmp(info.name, ".") => 0;
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lfs_dir_read(&lfs, &dir[0], &info) => 1;
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strcmp(info.name, "..") => 0;
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lfs_dir_read(&lfs, &dir[0], &info) => 1;
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strcmp(info.name, "hi") => 0;
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lfs_dir_read(&lfs, &dir[0], &info) => 0;
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lfs_unmount(&lfs) => 0;
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TEST
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echo "--- Move dir corrupt source ---"
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tests/test.py << TEST
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lfs_mount(&lfs, &cfg) => 0;
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lfs_rename(&lfs, "b/hi", "c/hi") => 0;
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lfs_unmount(&lfs) => 0;
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TEST
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rm -v blocks/7
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tests/test.py << TEST
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lfs_mount(&lfs, &cfg) => 0;
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lfs_dir_open(&lfs, &dir[0], "b") => 0;
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lfs_dir_read(&lfs, &dir[0], &info) => 1;
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strcmp(info.name, ".") => 0;
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lfs_dir_read(&lfs, &dir[0], &info) => 1;
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strcmp(info.name, "..") => 0;
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lfs_dir_read(&lfs, &dir[0], &info) => 0;
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lfs_dir_close(&lfs, &dir[0]) => 0;
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lfs_dir_open(&lfs, &dir[0], "c") => 0;
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lfs_dir_read(&lfs, &dir[0], &info) => 1;
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strcmp(info.name, ".") => 0;
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lfs_dir_read(&lfs, &dir[0], &info) => 1;
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strcmp(info.name, "..") => 0;
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lfs_dir_read(&lfs, &dir[0], &info) => 1;
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strcmp(info.name, "hello") => 0;
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lfs_dir_read(&lfs, &dir[0], &info) => 1;
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strcmp(info.name, "hi") => 0;
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lfs_dir_read(&lfs, &dir[0], &info) => 0;
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lfs_unmount(&lfs) => 0;
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TEST
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echo "--- Move dir corrupt source and dest ---"
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tests/test.py << TEST
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lfs_mount(&lfs, &cfg) => 0;
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lfs_rename(&lfs, "c/hi", "d/hi") => 0;
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lfs_unmount(&lfs) => 0;
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TEST
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rm -v blocks/9
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rm -v blocks/a
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tests/test.py << TEST
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lfs_mount(&lfs, &cfg) => 0;
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lfs_dir_open(&lfs, &dir[0], "c") => 0;
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lfs_dir_read(&lfs, &dir[0], &info) => 1;
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strcmp(info.name, ".") => 0;
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lfs_dir_read(&lfs, &dir[0], &info) => 1;
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strcmp(info.name, "..") => 0;
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lfs_dir_read(&lfs, &dir[0], &info) => 1;
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strcmp(info.name, "hello") => 0;
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lfs_dir_read(&lfs, &dir[0], &info) => 1;
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strcmp(info.name, "hi") => 0;
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lfs_dir_read(&lfs, &dir[0], &info) => 0;
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lfs_dir_close(&lfs, &dir[0]) => 0;
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lfs_dir_open(&lfs, &dir[0], "d") => 0;
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lfs_dir_read(&lfs, &dir[0], &info) => 1;
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strcmp(info.name, ".") => 0;
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lfs_dir_read(&lfs, &dir[0], &info) => 1;
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strcmp(info.name, "..") => 0;
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lfs_dir_read(&lfs, &dir[0], &info) => 0;
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lfs_unmount(&lfs) => 0;
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TEST
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echo "--- Move check ---"
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tests/test.py << TEST
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lfs_mount(&lfs, &cfg) => 0;
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lfs_dir_open(&lfs, &dir[0], "a/hi") => LFS_ERR_NOENT;
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lfs_dir_open(&lfs, &dir[0], "b/hi") => LFS_ERR_NOENT;
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lfs_dir_open(&lfs, &dir[0], "d/hi") => LFS_ERR_NOENT;
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lfs_dir_open(&lfs, &dir[0], "c/hi") => 0;
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lfs_dir_read(&lfs, &dir[0], &info) => 1;
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strcmp(info.name, ".") => 0;
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lfs_dir_read(&lfs, &dir[0], &info) => 1;
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strcmp(info.name, "..") => 0;
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lfs_dir_read(&lfs, &dir[0], &info) => 1;
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strcmp(info.name, "hola") => 0;
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lfs_dir_read(&lfs, &dir[0], &info) => 1;
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strcmp(info.name, "bonjour") => 0;
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lfs_dir_read(&lfs, &dir[0], &info) => 1;
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strcmp(info.name, "ohayo") => 0;
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lfs_dir_read(&lfs, &dir[0], &info) => 0;
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lfs_dir_close(&lfs, &dir[0]) => 0;
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lfs_dir_open(&lfs, &dir[0], "a/hello") => LFS_ERR_NOENT;
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lfs_dir_open(&lfs, &dir[0], "b/hello") => LFS_ERR_NOENT;
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lfs_dir_open(&lfs, &dir[0], "d/hello") => LFS_ERR_NOENT;
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lfs_file_open(&lfs, &file[0], "c/hello", LFS_O_RDONLY) => 0;
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lfs_file_read(&lfs, &file[0], buffer, 5) => 5;
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memcmp(buffer, "hola\n", 5) => 0;
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lfs_file_read(&lfs, &file[0], buffer, 8) => 8;
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memcmp(buffer, "bonjour\n", 8) => 0;
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lfs_file_read(&lfs, &file[0], buffer, 6) => 6;
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memcmp(buffer, "ohayo\n", 6) => 0;
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lfs_file_close(&lfs, &file[0]) => 0;
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lfs_unmount(&lfs) => 0;
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TEST
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echo "--- Results ---"
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tests/stats.py
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