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Merge "libfiemap: Only call FS_IOC_FIEMAP once."

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David Anderson 2021-11-01 22:55:45 +00:00 committed by Gerrit Code Review
commit 51f36da47a
1 changed files with 7 additions and 45 deletions
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52
fs_mgr/libfiemap/fiemap_writer.cpp
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@ -498,24 +498,6 @@ bool FiemapWriter::HasPinnedExtents(const std::string& file_path) {
return IsFilePinned(fd, file_path, sfs.f_type);
}
static bool CountFiemapExtents(int file_fd, const std::string& file_path, uint32_t* num_extents) {
struct fiemap fiemap = {};
fiemap.fm_start = 0;
fiemap.fm_length = UINT64_MAX;
fiemap.fm_flags = FIEMAP_FLAG_SYNC;
fiemap.fm_extent_count = 0;
if (ioctl(file_fd, FS_IOC_FIEMAP, &fiemap)) {
PLOG(ERROR) << "Failed to get FIEMAP from the kernel for file: " << file_path;
return false;
}
if (num_extents) {
*num_extents = fiemap.fm_mapped_extents;
}
return true;
}
static bool IsValidExtent(const fiemap_extent* extent, std::string_view file_path) {
if (extent->fe_flags & kUnsupportedExtentFlags) {
LOG(ERROR) << "Extent at location " << extent->fe_logical << " of file " << file_path
@ -530,12 +512,12 @@ static bool IsLastExtent(const fiemap_extent* extent) {
}
static bool FiemapToExtents(struct fiemap* fiemap, std::vector<struct fiemap_extent>* extents,
uint32_t num_extents, std::string_view file_path) {
if (num_extents == 0) return false;
std::string_view file_path) {
uint32_t num_extents = fiemap->fm_mapped_extents;
const struct fiemap_extent* last_extent = &fiemap->fm_extents[num_extents - 1];
if (!IsLastExtent(last_extent)) {
LOG(ERROR) << "FIEMAP did not return a final extent for file: " << file_path;
LOG(ERROR) << "FIEMAP did not return a final extent for file: " << file_path
<< " num_extents=" << num_extents << " max_extents=" << kMaxExtents;
return false;
}
@ -577,21 +559,7 @@ static bool FiemapToExtents(struct fiemap* fiemap, std::vector<struct fiemap_ext
static bool ReadFiemap(int file_fd, const std::string& file_path,
std::vector<struct fiemap_extent>* extents) {
uint32_t num_extents;
if (!CountFiemapExtents(file_fd, file_path, &num_extents)) {
return false;
}
if (num_extents == 0) {
LOG(ERROR) << "File " << file_path << " has zero extents";
return false;
}
if (num_extents > kMaxExtents) {
LOG(ERROR) << "File has " << num_extents << ", maximum is " << kMaxExtents << ": "
<< file_path;
return false;
}
uint64_t fiemap_size = sizeof(struct fiemap) + num_extents * sizeof(struct fiemap_extent);
uint64_t fiemap_size = sizeof(struct fiemap) + kMaxExtents * sizeof(struct fiemap_extent);
auto buffer = std::unique_ptr<void, decltype(&free)>(calloc(1, fiemap_size), free);
if (buffer == nullptr) {
LOG(ERROR) << "Failed to allocate memory for fiemap";
@ -603,19 +571,13 @@ static bool ReadFiemap(int file_fd, const std::string& file_path,
fiemap->fm_length = UINT64_MAX;
// make sure file is synced to disk before we read the fiemap
fiemap->fm_flags = FIEMAP_FLAG_SYNC;
fiemap->fm_extent_count = num_extents;
fiemap->fm_extent_count = kMaxExtents;
if (ioctl(file_fd, FS_IOC_FIEMAP, fiemap)) {
PLOG(ERROR) << "Failed to get FIEMAP from the kernel for file: " << file_path;
return false;
}
if (fiemap->fm_mapped_extents != num_extents) {
LOG(ERROR) << "FIEMAP returned unexpected extent count (" << num_extents
<< " expected, got " << fiemap->fm_mapped_extents << ") for file: " << file_path;
return false;
}
return FiemapToExtents(fiemap, extents, num_extents, file_path);
return FiemapToExtents(fiemap, extents, file_path);
}
static bool ReadFibmap(int file_fd, const std::string& file_path,