diff options
Diffstat (limited to 'src/import/export-raw.c')
| -rw-r--r-- | src/import/export-raw.c | 332 |
1 files changed, 332 insertions, 0 deletions
diff --git a/src/import/export-raw.c b/src/import/export-raw.c new file mode 100644 index 0000000..6a02b47 --- /dev/null +++ b/src/import/export-raw.c @@ -0,0 +1,332 @@ +/* SPDX-License-Identifier: LGPL-2.1+ */ + +#include <sys/sendfile.h> + +/* When we include libgen.h because we need dirname() we immediately + * undefine basename() since libgen.h defines it as a macro to the POSIX + * version which is really broken. We prefer GNU basename(). */ +#include <libgen.h> +#undef basename + +#include "sd-daemon.h" + +#include "alloc-util.h" +#include "btrfs-util.h" +#include "copy.h" +#include "export-raw.h" +#include "fd-util.h" +#include "fs-util.h" +#include "import-common.h" +#include "missing.h" +#include "ratelimit.h" +#include "stat-util.h" +#include "string-util.h" +#include "tmpfile-util.h" +#include "util.h" + +#define COPY_BUFFER_SIZE (16*1024) + +struct RawExport { + sd_event *event; + + RawExportFinished on_finished; + void *userdata; + + char *path; + + int input_fd; + int output_fd; + + ImportCompress compress; + + sd_event_source *output_event_source; + + void *buffer; + size_t buffer_size; + size_t buffer_allocated; + + uint64_t written_compressed; + uint64_t written_uncompressed; + + unsigned last_percent; + RateLimit progress_rate_limit; + + struct stat st; + + bool eof; + bool tried_reflink; + bool tried_sendfile; +}; + +RawExport *raw_export_unref(RawExport *e) { + if (!e) + return NULL; + + sd_event_source_unref(e->output_event_source); + + import_compress_free(&e->compress); + + sd_event_unref(e->event); + + safe_close(e->input_fd); + + free(e->buffer); + free(e->path); + return mfree(e); +} + +int raw_export_new( + RawExport **ret, + sd_event *event, + RawExportFinished on_finished, + void *userdata) { + + _cleanup_(raw_export_unrefp) RawExport *e = NULL; + int r; + + assert(ret); + + e = new(RawExport, 1); + if (!e) + return -ENOMEM; + + *e = (RawExport) { + .output_fd = -1, + .input_fd = -1, + .on_finished = on_finished, + .userdata = userdata, + .last_percent = (unsigned) -1, + }; + + RATELIMIT_INIT(e->progress_rate_limit, 100 * USEC_PER_MSEC, 1); + + if (event) + e->event = sd_event_ref(event); + else { + r = sd_event_default(&e->event); + if (r < 0) + return r; + } + + *ret = TAKE_PTR(e); + + return 0; +} + +static void raw_export_report_progress(RawExport *e) { + unsigned percent; + assert(e); + + if (e->written_uncompressed >= (uint64_t) e->st.st_size) + percent = 100; + else + percent = (unsigned) ((e->written_uncompressed * UINT64_C(100)) / (uint64_t) e->st.st_size); + + if (percent == e->last_percent) + return; + + if (!ratelimit_below(&e->progress_rate_limit)) + return; + + sd_notifyf(false, "X_IMPORT_PROGRESS=%u", percent); + log_info("Exported %u%%.", percent); + + e->last_percent = percent; +} + +static int raw_export_process(RawExport *e) { + ssize_t l; + int r; + + assert(e); + + if (!e->tried_reflink && e->compress.type == IMPORT_COMPRESS_UNCOMPRESSED) { + + /* If we shall take an uncompressed snapshot we can + * reflink source to destination directly. Let's see + * if this works. */ + + r = btrfs_reflink(e->input_fd, e->output_fd); + if (r >= 0) { + r = 0; + goto finish; + } + + e->tried_reflink = true; + } + + if (!e->tried_sendfile && e->compress.type == IMPORT_COMPRESS_UNCOMPRESSED) { + + l = sendfile(e->output_fd, e->input_fd, NULL, COPY_BUFFER_SIZE); + if (l < 0) { + if (errno == EAGAIN) + return 0; + + e->tried_sendfile = true; + } else if (l == 0) { + r = 0; + goto finish; + } else { + e->written_uncompressed += l; + e->written_compressed += l; + + raw_export_report_progress(e); + + return 0; + } + } + + while (e->buffer_size <= 0) { + uint8_t input[COPY_BUFFER_SIZE]; + + if (e->eof) { + r = 0; + goto finish; + } + + l = read(e->input_fd, input, sizeof(input)); + if (l < 0) { + r = log_error_errno(errno, "Failed to read raw file: %m"); + goto finish; + } + + if (l == 0) { + e->eof = true; + r = import_compress_finish(&e->compress, &e->buffer, &e->buffer_size, &e->buffer_allocated); + } else { + e->written_uncompressed += l; + r = import_compress(&e->compress, input, l, &e->buffer, &e->buffer_size, &e->buffer_allocated); + } + if (r < 0) { + r = log_error_errno(r, "Failed to encode: %m"); + goto finish; + } + } + + l = write(e->output_fd, e->buffer, e->buffer_size); + if (l < 0) { + if (errno == EAGAIN) + return 0; + + r = log_error_errno(errno, "Failed to write output file: %m"); + goto finish; + } + + assert((size_t) l <= e->buffer_size); + memmove(e->buffer, (uint8_t*) e->buffer + l, e->buffer_size - l); + e->buffer_size -= l; + e->written_compressed += l; + + raw_export_report_progress(e); + + return 0; + +finish: + if (r >= 0) { + (void) copy_times(e->input_fd, e->output_fd); + (void) copy_xattr(e->input_fd, e->output_fd); + } + + if (e->on_finished) + e->on_finished(e, r, e->userdata); + else + sd_event_exit(e->event, r); + + return 0; +} + +static int raw_export_on_output(sd_event_source *s, int fd, uint32_t revents, void *userdata) { + RawExport *i = userdata; + + return raw_export_process(i); +} + +static int raw_export_on_defer(sd_event_source *s, void *userdata) { + RawExport *i = userdata; + + return raw_export_process(i); +} + +static int reflink_snapshot(int fd, const char *path) { + int new_fd, r; + + new_fd = open_parent(path, O_TMPFILE|O_CLOEXEC|O_RDWR, 0600); + if (new_fd < 0) { + _cleanup_free_ char *t = NULL; + + r = tempfn_random(path, NULL, &t); + if (r < 0) + return r; + + new_fd = open(t, O_CLOEXEC|O_CREAT|O_NOCTTY|O_RDWR, 0600); + if (new_fd < 0) + return -errno; + + (void) unlink(t); + } + + r = btrfs_reflink(fd, new_fd); + if (r < 0) { + safe_close(new_fd); + return r; + } + + return new_fd; +} + +int raw_export_start(RawExport *e, const char *path, int fd, ImportCompressType compress) { + _cleanup_close_ int sfd = -1, tfd = -1; + int r; + + assert(e); + assert(path); + assert(fd >= 0); + assert(compress < _IMPORT_COMPRESS_TYPE_MAX); + assert(compress != IMPORT_COMPRESS_UNKNOWN); + + if (e->output_fd >= 0) + return -EBUSY; + + r = fd_nonblock(fd, true); + if (r < 0) + return r; + + r = free_and_strdup(&e->path, path); + if (r < 0) + return r; + + sfd = open(path, O_RDONLY|O_CLOEXEC|O_NOCTTY); + if (sfd < 0) + return -errno; + + if (fstat(sfd, &e->st) < 0) + return -errno; + r = stat_verify_regular(&e->st); + if (r < 0) + return r; + + /* Try to take a reflink snapshot of the file, if we can t make the export atomic */ + tfd = reflink_snapshot(sfd, path); + if (tfd >= 0) + e->input_fd = TAKE_FD(tfd); + else + e->input_fd = TAKE_FD(sfd); + + r = import_compress_init(&e->compress, compress); + if (r < 0) + return r; + + r = sd_event_add_io(e->event, &e->output_event_source, fd, EPOLLOUT, raw_export_on_output, e); + if (r == -EPERM) { + r = sd_event_add_defer(e->event, &e->output_event_source, raw_export_on_defer, e); + if (r < 0) + return r; + + r = sd_event_source_set_enabled(e->output_event_source, SD_EVENT_ON); + } + if (r < 0) + return r; + + e->output_fd = fd; + return r; +} |