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Merge "snapuserd: Restrict where reads/writes to dm_user_header happen." into main

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This commit is contained in:
David Anderson 2023-07-12 03:09:06 +00:00 • committed by Gerrit Code Review
commit 80afdc08f5
2 changed files with 34 additions and 51 deletions
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1
fs_mgr/libsnapshot/snapuserd/user-space-merge/snapuserd_core.h
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@ -119,7 +119,6 @@ class Worker {
}
// Functions interacting with dm-user
bool ReadDmUserHeader();
bool WriteDmUserPayload(size_t size);
bool DmuserReadRequest();

84
fs_mgr/libsnapshot/snapuserd/user-space-merge/snapuserd_dm_user.cpp
View file

@ -290,21 +290,6 @@ bool Worker::RunThread() {
return true;
}
// Read Header from dm-user misc device. This gives
// us the sector number for which IO is issued by dm-snapshot device
bool Worker::ReadDmUserHeader() {
if (!android::base::ReadFully(ctrl_fd_, bufsink_.GetBufPtr(), sizeof(struct dm_user_header))) {
if (errno != ENOTBLK) {
SNAP_PLOG(ERROR) << "Control-read failed";
}
SNAP_PLOG(DEBUG) << "ReadDmUserHeader failed....";
return false;
}
return true;
}
// Send the payload/data back to dm-user misc device.
bool Worker::WriteDmUserPayload(size_t size) {
size_t payload_size = size;
@ -345,19 +330,15 @@ bool Worker::ReadDataFromBaseDevice(sector_t sector, size_t read_size) {
}
bool Worker::ReadAlignedSector(sector_t sector, size_t sz) {
struct dm_user_header* header = bufsink_.GetHeaderPtr();
size_t remaining_size = sz;
std::vector<std::pair<sector_t, const CowOperation*>>& chunk_vec = snapuserd_->GetChunkVec();
bool io_error = false;
int ret = 0;
do {
// Process 1MB payload at a time
size_t read_size = std::min(PAYLOAD_BUFFER_SZ, remaining_size);
header->type = DM_USER_RESP_SUCCESS;
size_t total_bytes_read = 0;
io_error = false;
bufsink_.ResetBufferOffset();
while (read_size) {
@ -375,7 +356,7 @@ bool Worker::ReadAlignedSector(sector_t sector, size_t sz) {
// device.
if (!ReadDataFromBaseDevice(sector, size)) {
SNAP_LOG(ERROR) << "ReadDataFromBaseDevice failed";
header->type = DM_USER_RESP_ERROR;
return false;
}
ret = size;
@ -384,35 +365,26 @@ bool Worker::ReadAlignedSector(sector_t sector, size_t sz) {
// process it.
if (!ProcessCowOp(it->second)) {
SNAP_LOG(ERROR) << "ProcessCowOp failed";
header->type = DM_USER_RESP_ERROR;
return false;
}
ret = BLOCK_SZ;
}
// Just return the header if it is an error
if (header->type == DM_USER_RESP_ERROR) {
RespondIOError();
io_error = true;
break;
}
read_size -= ret;
total_bytes_read += ret;
sector += (ret >> SECTOR_SHIFT);
bufsink_.UpdateBufferOffset(ret);
}
if (!io_error) {
if (!WriteDmUserPayload(total_bytes_read)) {
return false;
}
SNAP_LOG(DEBUG) << "WriteDmUserPayload success total_bytes_read: " << total_bytes_read
<< " remaining_size: " << remaining_size;
remaining_size -= total_bytes_read;
if (!WriteDmUserPayload(total_bytes_read)) {
return false;
}
} while (remaining_size > 0 && !io_error);
SNAP_LOG(DEBUG) << "WriteDmUserPayload success total_bytes_read: " << total_bytes_read
<< " remaining_size: " << remaining_size;
remaining_size -= total_bytes_read;
} while (remaining_size > 0);
return true;
}
@ -453,8 +425,6 @@ int Worker::ReadUnalignedSector(
}
bool Worker::ReadUnalignedSector(sector_t sector, size_t size) {
struct dm_user_header* header = bufsink_.GetHeaderPtr();
header->type = DM_USER_RESP_SUCCESS;
bufsink_.ResetBufferOffset();
std::vector<std::pair<sector_t, const CowOperation*>>& chunk_vec = snapuserd_->GetChunkVec();
@ -622,9 +592,15 @@ bool Worker::DmuserReadRequest() {
}
bool Worker::ProcessIORequest() {
// Read Header from dm-user misc device. This gives
// us the sector number for which IO is issued by dm-snapshot device
struct dm_user_header* header = bufsink_.GetHeaderPtr();
if (!android::base::ReadFully(ctrl_fd_, header, sizeof(*header))) {
if (errno != ENOTBLK) {
SNAP_PLOG(ERROR) << "Control-read failed";
}
if (!ReadDmUserHeader()) {
SNAP_PLOG(DEBUG) << "ReadDmUserHeader failed....";
return false;
}
@ -634,26 +610,34 @@ bool Worker::ProcessIORequest() {
SNAP_LOG(DEBUG) << "Daemon: msg->type: " << std::dec << header->type;
SNAP_LOG(DEBUG) << "Daemon: msg->flags: " << std::dec << header->flags;
// Use the same header buffer as the response header.
int request_type = header->type;
header->type = DM_USER_RESP_SUCCESS;
header_response_ = true;
switch (header->type) {
case DM_USER_REQ_MAP_READ: {
if (!DmuserReadRequest()) {
return false;
}
bool ok;
switch (request_type) {
case DM_USER_REQ_MAP_READ:
ok = DmuserReadRequest();
break;
}
case DM_USER_REQ_MAP_WRITE: {
case DM_USER_REQ_MAP_WRITE:
// TODO: We should not get any write request
// to dm-user as we mount all partitions
// as read-only. Need to verify how are TRIM commands
// handled during mount.
return false;
}
ok = false;
break;
default:
ok = false;
break;
}
return true;
if (!ok && header->type != DM_USER_RESP_ERROR) {
RespondIOError();
}
return ok;
}
} // namespace snapshot