Fixed file truncation without writes

In the open call, the LFS_O_TRUNC flag was correctly zeroing the file, but
it wasn't actually writing the change out to disk. This went unnoticed because
in the cases where the truncate was followed by a file write, the
updated contents would be written out correctly.

Marking the file as dirty if the file isn't already truncated fixes the
problem with the least impact. Also added better test cases around
truncating files.
This commit is contained in:
Christopher Haster
2018-01-11 10:26:33 -06:00
parent aea3d3db46
commit 472ccc4203
2 changed files with 30 additions and 2 deletions

3
lfs.c
View File

@@ -1261,6 +1261,9 @@ int lfs_file_open(lfs_t *lfs, lfs_file_t *file,
file->pos = 0; file->pos = 0;
if (flags & LFS_O_TRUNC) { if (flags & LFS_O_TRUNC) {
if (file->size != 0) {
file->flags |= LFS_F_DIRTY;
}
file->head = 0xffffffff; file->head = 0xffffffff;
file->size = 0; file->size = 0;
} }

View File

@@ -34,7 +34,8 @@ tests/test.py << TEST
lfs_size_t chunk = 31; lfs_size_t chunk = 31;
srand(0); srand(0);
lfs_mount(&lfs, &cfg) => 0; lfs_mount(&lfs, &cfg) => 0;
lfs_file_open(&lfs, &file[0], "$2", LFS_O_WRONLY | LFS_O_CREAT) => 0; lfs_file_open(&lfs, &file[0], "$2",
${3:-LFS_O_WRONLY | LFS_O_CREAT | LFS_O_TRUNC}) => 0;
for (lfs_size_t i = 0; i < size; i += chunk) { for (lfs_size_t i = 0; i < size; i += chunk) {
chunk = (chunk < size - i) ? chunk : size - i; chunk = (chunk < size - i) ? chunk : size - i;
for (lfs_size_t b = 0; b < chunk; b++) { for (lfs_size_t b = 0; b < chunk; b++) {
@@ -53,7 +54,10 @@ tests/test.py << TEST
lfs_size_t chunk = 29; lfs_size_t chunk = 29;
srand(0); srand(0);
lfs_mount(&lfs, &cfg) => 0; lfs_mount(&lfs, &cfg) => 0;
lfs_file_open(&lfs, &file[0], "$2", LFS_O_RDONLY) => 0; lfs_stat(&lfs, "$2", &info) => 0;
info.type => LFS_TYPE_REG;
info.size => size;
lfs_file_open(&lfs, &file[0], "$2", ${3:-LFS_O_RDONLY}) => 0;
for (lfs_size_t i = 0; i < size; i += chunk) { for (lfs_size_t i = 0; i < size; i += chunk) {
chunk = (chunk < size - i) ? chunk : size - i; chunk = (chunk < size - i) ? chunk : size - i;
lfs_file_read(&lfs, &file[0], buffer, chunk) => chunk; lfs_file_read(&lfs, &file[0], buffer, chunk) => chunk;
@@ -78,10 +82,27 @@ echo "--- Large file test ---"
w_test $LARGESIZE largeavacado w_test $LARGESIZE largeavacado
r_test $LARGESIZE largeavacado r_test $LARGESIZE largeavacado
echo "--- Zero file test ---"
w_test 0 noavacado
r_test 0 noavacado
echo "--- Truncate small test ---"
w_test $SMALLSIZE mediumavacado
r_test $SMALLSIZE mediumavacado
w_test $MEDIUMSIZE mediumavacado
r_test $MEDIUMSIZE mediumavacado
echo "--- Truncate zero test ---"
w_test $SMALLSIZE noavacado
r_test $SMALLSIZE noavacado
w_test 0 noavacado
r_test 0 noavacado
echo "--- Non-overlap check ---" echo "--- Non-overlap check ---"
r_test $SMALLSIZE smallavacado r_test $SMALLSIZE smallavacado
r_test $MEDIUMSIZE mediumavacado r_test $MEDIUMSIZE mediumavacado
r_test $LARGESIZE largeavacado r_test $LARGESIZE largeavacado
r_test 0 noavacado
echo "--- Dir check ---" echo "--- Dir check ---"
tests/test.py << TEST tests/test.py << TEST
@@ -105,6 +126,10 @@ tests/test.py << TEST
strcmp(info.name, "largeavacado") => 0; strcmp(info.name, "largeavacado") => 0;
info.type => LFS_TYPE_REG; info.type => LFS_TYPE_REG;
info.size => $LARGESIZE; info.size => $LARGESIZE;
lfs_dir_read(&lfs, &dir[0], &info) => 1;
strcmp(info.name, "noavacado") => 0;
info.type => LFS_TYPE_REG;
info.size => 0;
lfs_dir_read(&lfs, &dir[0], &info) => 0; lfs_dir_read(&lfs, &dir[0], &info) => 0;
lfs_dir_close(&lfs, &dir[0]) => 0; lfs_dir_close(&lfs, &dir[0]) => 0;
lfs_unmount(&lfs) => 0; lfs_unmount(&lfs) => 0;