Fixed issue with superblock breaking lfs_dir_seek

The superblock entry takes up id 0 in the root directory (not all
entries are files, though currently the superblock is the only
exception). Normally, reading a directory correctly skips the
superblock and only reports non-superblock files.

However, this doesn't work perfectly for lfs_dir_seek, which tries
to be clever to not touch the disk.

Fortunately, we can fix this by adding an offset for the superblock.
This will only work while the superblock is the only non-file entry,
otherwise we would need to touch the disk to properly seek in a
directory (though we already touch the disk a bit to get dir-tails
during seeks).

Found by jhartika
This commit is contained in:
Christopher Haster
2019-11-27 11:27:30 -06:00
parent 1f11e6b78a
commit 0197b18100
2 changed files with 84 additions and 4 deletions

View File

@@ -428,4 +428,78 @@ scripts/test.py << TEST
TEST
done
echo "--- Root seek test ---"
./scripts/test.py << TEST
lfs_mount(&lfs, &cfg) => 0;
for (int i = 3; i < $MEDIUMSIZE; i++) {
sprintf(path, "hi%03d", i);
lfs_mkdir(&lfs, path) => 0;
}
lfs_dir_open(&lfs, &dir, "/") => 0;
for (int i = 0; i < $MEDIUMSIZE; i++) {
if (i == 0) {
sprintf(path, ".");
} else if (i == 1) {
sprintf(path, "..");
} else if (i == 2) {
sprintf(path, "hello");
} else {
sprintf(path, "hi%03d", i);
}
lfs_dir_read(&lfs, &dir, &info) => 1;
strcmp(path, info.name) => 0;
}
lfs_dir_read(&lfs, &dir, &info) => 0;
lfs_dir_close(&lfs, &dir) => 0;
for (int j = 0; j < $MEDIUMSIZE; j++) {
lfs_soff_t off = -1;
lfs_dir_open(&lfs, &dir, "/") => 0;
for (int i = 0; i < $MEDIUMSIZE; i++) {
if (i == 0) {
sprintf(path, ".");
} else if (i == 1) {
sprintf(path, "..");
} else if (i == 2) {
sprintf(path, "hello");
} else {
sprintf(path, "hi%03d", i);
}
if (i == j) {
off = lfs_dir_tell(&lfs, &dir);
off >= 0 => true;
}
lfs_dir_read(&lfs, &dir, &info) => 1;
strcmp(path, info.name) => 0;
}
lfs_dir_read(&lfs, &dir, &info) => 0;
lfs_dir_close(&lfs, &dir) => 0;
lfs_dir_open(&lfs, &dir, "/") => 0;
lfs_dir_seek(&lfs, &dir, off) => 0;
for (int i = j; i < $MEDIUMSIZE; i++) {
if (i == 0) {
sprintf(path, ".");
} else if (i == 1) {
sprintf(path, "..");
} else if (i == 2) {
sprintf(path, "hello");
} else {
sprintf(path, "hi%03d", i);
}
lfs_dir_read(&lfs, &dir, &info) => 1;
strcmp(path, info.name) => 0;
}
lfs_dir_read(&lfs, &dir, &info) => 0;
lfs_dir_close(&lfs, &dir) => 0;
}
lfs_unmount(&lfs) => 0;
TEST
scripts/results.py