Commit f8240ce9 authored by AKASHI Takahiro's avatar AKASHI Takahiro Committed by Alexander Graf

fs: fat: support unlink

In this patch, unlink support is added to FAT file system.
A directory can be deleted only if it is empty.

In this implementation, only a directory entry for a short file name
will be removed. So entries for a long file name can and should be
reclaimed with fsck.
Signed-off-by: default avatarAKASHI Takahiro <takahiro.akashi@linaro.org>
Signed-off-by: Alexander Graf's avatarAlexander Graf <agraf@suse.de>
parent e2519daf
......@@ -1184,6 +1184,138 @@ int file_fat_write(const char *filename, void *buffer, loff_t offset,
return file_fat_write_at(filename, offset, buffer, maxsize, actwrite);
}
static int fat_dir_entries(fat_itr *itr)
{
fat_itr *dirs;
fsdata fsdata = { .fatbuf = NULL, }, *mydata = &fsdata;
/* for FATBUFSIZE */
int count;
dirs = malloc_cache_aligned(sizeof(fat_itr));
if (!dirs) {
debug("Error: allocating memory\n");
count = -ENOMEM;
goto exit;
}
/* duplicate fsdata */
fat_itr_child(dirs, itr);
fsdata = *dirs->fsdata;
/* allocate local fat buffer */
fsdata.fatbuf = malloc_cache_aligned(FATBUFSIZE);
if (!fsdata.fatbuf) {
debug("Error: allocating memory\n");
count = -ENOMEM;
goto exit;
}
fsdata.fatbufnum = -1;
dirs->fsdata = &fsdata;
for (count = 0; fat_itr_next(dirs); count++)
;
exit:
free(fsdata.fatbuf);
free(dirs);
return count;
}
static int delete_dentry(fat_itr *itr)
{
fsdata *mydata = itr->fsdata;
dir_entry *dentptr = itr->dent;
/* free cluster blocks */
clear_fatent(mydata, START(dentptr));
if (flush_dirty_fat_buffer(mydata) < 0) {
printf("Error: flush fat buffer\n");
return -EIO;
}
/*
* update a directory entry
* TODO:
* - long file name support
* - find and mark the "new" first invalid entry as name[0]=0x00
*/
memset(dentptr, 0, sizeof(*dentptr));
dentptr->name[0] = 0xe5;
if (set_cluster(mydata, itr->clust, itr->block,
mydata->clust_size * mydata->sect_size) != 0) {
printf("error: writing directory entry\n");
return -EIO;
}
return 0;
}
int fat_unlink(const char *filename)
{
fsdata fsdata = { .fatbuf = NULL, };
fat_itr *itr = NULL;
int n_entries, ret;
char *filename_copy, *dirname, *basename;
filename_copy = strdup(filename);
split_filename(filename_copy, &dirname, &basename);
if (!strcmp(dirname, "/") && !strcmp(basename, "")) {
printf("Error: cannot remove root\n");
ret = -EINVAL;
goto exit;
}
itr = malloc_cache_aligned(sizeof(fat_itr));
if (!itr) {
printf("Error: allocating memory\n");
return -ENOMEM;
}
ret = fat_itr_root(itr, &fsdata);
if (ret)
goto exit;
total_sector = fsdata.total_sect;
ret = fat_itr_resolve(itr, dirname, TYPE_DIR);
if (ret) {
printf("%s: doesn't exist (%d)\n", dirname, ret);
ret = -ENOENT;
goto exit;
}
if (!find_directory_entry(itr, basename)) {
printf("%s: doesn't exist\n", basename);
ret = -ENOENT;
goto exit;
}
if (fat_itr_isdir(itr)) {
n_entries = fat_dir_entries(itr);
if (n_entries < 0) {
ret = n_entries;
goto exit;
}
if (n_entries > 2) {
printf("Error: directory is not empty: %d\n",
n_entries);
ret = -EINVAL;
goto exit;
}
}
ret = delete_dentry(itr);
exit:
free(fsdata.fatbuf);
free(itr);
free(filename_copy);
return ret;
}
int fat_mkdir(const char *new_dirname)
{
dir_entry *retdent;
......
......@@ -170,16 +170,17 @@ static struct fstype_info fstypes[] = {
.read = fat_read_file,
#ifdef CONFIG_FAT_WRITE
.write = file_fat_write,
.unlink = fat_unlink,
.mkdir = fat_mkdir,
#else
.write = fs_write_unsupported,
.unlink = fs_unlink_unsupported,
.mkdir = fs_mkdir_unsupported,
#endif
.uuid = fs_uuid_unsupported,
.opendir = fat_opendir,
.readdir = fat_readdir,
.closedir = fat_closedir,
.unlink = fs_unlink_unsupported,
},
#endif
#ifdef CONFIG_FS_EXT4
......
......@@ -203,6 +203,7 @@ int fat_read_file(const char *filename, void *buf, loff_t offset, loff_t len,
int fat_opendir(const char *filename, struct fs_dir_stream **dirsp);
int fat_readdir(struct fs_dir_stream *dirs, struct fs_dirent **dentp);
void fat_closedir(struct fs_dir_stream *dirs);
int fat_unlink(const char *filename);
int fat_mkdir(const char *dirname);
void fat_close(void);
#endif /* _FAT_H_ */
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment