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secdiscard: use F2FS_IOC_SEC_TRIM_FILE for secure discard

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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
This commit is contained in:
Daeho Jeong 2020-09-08 12:59:28 +09:00
parent 3d1b6ac7c0
commit d1b946ea9f
1 changed files with 46 additions and 5 deletions
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51
secdiscard.cpp
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@ -50,6 +50,27 @@ bool overwrite_with_zeros(int fd, off64_t start, off64_t length);
} // 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 @@ int main(int argc, const char* const argv[]) {
// 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 @@ int main(int argc, const char* const argv[]) {
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) {