secdiscard: use F2FS_IOC_SEC_TRIM_FILE for secure discard
A new interface, F2FS_IOC_SEC_TRIM_FILE, has been added to F2FS
filesystem to send secure discard command to a specific file,
not to block device. We can use this interface for better discard
command handling on a file basis.
[how to use F2FS_IOC_SEC_TRIM_FILE]
start: start offset in byte (should be aligned with 4096)
len: length in byte (should be aligned with 4096, except designating EOF)
-1 also means till EOF.
flags: F2FS_TRIM_FILE_DISCARD - sending secure discard command. If the
device doesn't support it, send normal
discard.
F2FS_TRIM_FILE_ZEROOUT - overwrite zero data in the file.
Bug: 140759142
Test: execute "secdiscard -- <file_path>" and check the content of file
Signed-off-by: Daeho Jeong <daehojeong@google.com>
Change-Id: I6ee44a047d291274c9d70ae5e4ccccfc06a52f89
diff --git a/secdiscard.cpp b/secdiscard.cpp
index 4659eed..b91f321 100644
--- a/secdiscard.cpp
+++ b/secdiscard.cpp
@@ -50,6 +50,27 @@
} // namespace
+#ifndef F2FS_IOCTL_MAGIC
+#define F2FS_IOCTL_MAGIC 0xf5
+#endif
+
+// F2FS-specific ioctl
+// It requires the below kernel commit merged in v5.9-rc1.
+// 9af846486d78 ("f2fs: add F2FS_IOC_SEC_TRIM_FILE ioctl")
+// In android12-5.4,
+// 7fc27297c44d ("Merge remote-tracking branch 'aosp/upstream-f2fs-stable-linux-5.4.y'
+// into android12-5.4")
+#ifndef F2FS_IOC_SEC_TRIM_FILE
+struct f2fs_sectrim_range {
+ __u64 start;
+ __u64 len;
+ __u64 flags;
+};
+#define F2FS_IOC_SEC_TRIM_FILE _IOW(F2FS_IOCTL_MAGIC, 20, struct f2fs_sectrim_range)
+#define F2FS_TRIM_FILE_DISCARD 0x1
+#define F2FS_TRIM_FILE_ZEROOUT 0x2
+#endif
+
int main(int argc, const char* const argv[]) {
android::base::InitLogging(const_cast<char**>(argv));
Options options;
@@ -69,9 +90,6 @@
// In android-4.14,
// ce767d9a55bc ("f2fs: updates on v4.16-rc1")
#ifndef F2FS_IOC_SET_PIN_FILE
-#ifndef F2FS_IOCTL_MAGIC
-#define F2FS_IOCTL_MAGIC 0xf5
-#endif
#define F2FS_IOC_SET_PIN_FILE _IOW(F2FS_IOCTL_MAGIC, 13, __u32)
#define F2FS_IOC_GET_PIN_FILE _IOR(F2FS_IOCTL_MAGIC, 14, __u32)
#endif
@@ -85,8 +103,31 @@
ioctl(fd, F2FS_IOC_SET_PIN_FILE, &set);
LOG(DEBUG) << "Securely discarding '" << target << "' unlink=" << options.unlink;
- if (!secdiscard_path(target)) {
- LOG(ERROR) << "Secure discard failed for: " << target;
+ struct f2fs_sectrim_range secRange;
+ secRange.start = 0;
+ secRange.len = -1; // until end of file
+ secRange.flags = F2FS_TRIM_FILE_DISCARD | F2FS_TRIM_FILE_ZEROOUT;
+ /*
+ * F2FS_IOC_SEC_TRIM_FILE is only supported by F2FS.
+ * 1. If device supports secure discard, it sends secure discard command on the file.
+ * 2. Otherwise, it sends discard command on the file.
+ * 3. Lastly, it overwrites zero data on it.
+ */
+ int ret = ioctl(fd, F2FS_IOC_SEC_TRIM_FILE, &secRange);
+ if (ret != 0) {
+ if (errno == EOPNOTSUPP) {
+ // If device doesn't support any type of discard, just overwrite zero data.
+ secRange.flags = F2FS_TRIM_FILE_ZEROOUT;
+ ret = ioctl(fd, F2FS_IOC_SEC_TRIM_FILE, &secRange);
+ }
+ if (ret != 0 && errno != ENOTTY) {
+ PLOG(WARNING) << "F2FS_IOC_SEC_TRIM_FILE failed on " << target;
+ }
+ }
+ if (ret != 0) {
+ if (!secdiscard_path(target)) {
+ LOG(ERROR) << "Secure discard failed for: " << target;
+ }
}
if (options.unlink) {
if (unlink(target.c_str()) != 0 && errno != ENOENT) {