import: always use the same buffer size

Let's synchronize the buffer sizes used when passing around the disk
images, i.e. size both our internal buffers and the pipe buffers the
same (so that we can always write()/read() everything in one gone -
except for the noise compression inserts).

Let's also increase the buffer sizes from 16K to 128K, which made a
difference for me, because it reduces the number of syscalls quite a
bit.

src/import/export-raw.c

@@ -11,6 +11,7 @@
 #include "fd-util.h"
 #include "format-util.h"
 #include "fs-util.h"
+#include "import-common.h"
 #include "log.h"
 #include "pretty-print.h"
 #include "ratelimit.h"
@@ -20,8 +21,6 @@
 #include "time-util.h"
 #include "tmpfile-util.h"
 
-#define COPY_BUFFER_SIZE (16*1024)
-
 typedef struct RawExport {
         sd_event *event;
 
@@ -161,7 +160,7 @@ static int raw_export_process(RawExport *e) {
 
         if (!e->tried_sendfile && e->compress.type == IMPORT_COMPRESS_UNCOMPRESSED) {
 
-                l = sendfile(e->output_fd, e->input_fd, NULL, COPY_BUFFER_SIZE);
+                l = sendfile(e->output_fd, e->input_fd, NULL, IMPORT_BUFFER_SIZE);
                 if (l < 0) {
                         if (errno == EAGAIN)
                                 return 0;
@@ -181,7 +180,7 @@ static int raw_export_process(RawExport *e) {
         }
 
         while (e->buffer_size <= 0) {
-                uint8_t input[COPY_BUFFER_SIZE];
+                uint8_t input[IMPORT_BUFFER_SIZE];
 
                 if (e->eof) {
                         r = 0;

src/import/export-tar.c

@@ -20,8 +20,6 @@
 #include "time-util.h"
 #include "tmpfile-util.h"
 
-#define COPY_BUFFER_SIZE (16*1024)
-
 typedef struct TarExport {
         sd_event *event;
 
@@ -181,7 +179,7 @@ static int tar_export_process(TarExport *e) {
 
         if (!e->tried_splice && e->compress.type == IMPORT_COMPRESS_UNCOMPRESSED) {
 
-                l = splice(e->tar_fd, NULL, e->output_fd, NULL, COPY_BUFFER_SIZE, 0);
+                l = splice(e->tar_fd, NULL, e->output_fd, NULL, IMPORT_BUFFER_SIZE, 0);
                 if (l < 0) {
                         if (errno == EAGAIN)
                                 return 0;
@@ -201,7 +199,7 @@ static int tar_export_process(TarExport *e) {
         }
 
         while (e->buffer_size <= 0) {
-                uint8_t input[COPY_BUFFER_SIZE];
+                uint8_t input[IMPORT_BUFFER_SIZE];
 
                 if (e->eof) {
                         r = tar_export_finish(e);

src/import/import-common.c

@@ -32,6 +32,8 @@ int import_fork_tar_x(const char *path, pid_t *ret) {
         if (pipe2(pipefd, O_CLOEXEC) < 0)
                 return log_error_errno(errno, "Failed to create pipe for tar: %m");
 
+        (void) fcntl(pipefd[0], F_SETPIPE_SZ, IMPORT_BUFFER_SIZE);
+
         use_selinux = mac_selinux_use();
 
         r = safe_fork_full("(tar)",
@@ -101,6 +103,8 @@ int import_fork_tar_c(const char *path, pid_t *ret) {
         if (pipe2(pipefd, O_CLOEXEC) < 0)
                 return log_error_errno(errno, "Failed to create pipe for tar: %m");
 
+        (void) fcntl(pipefd[0], F_SETPIPE_SZ, IMPORT_BUFFER_SIZE);
+
         use_selinux = mac_selinux_use();
 
         r = safe_fork_full("(tar)",

src/import/import-common.h

@@ -41,3 +41,5 @@ int import_mangle_os_tree(const char *path);
 bool import_validate_local(const char *name, ImportFlags flags);
 
 int import_allocate_event_with_signals(sd_event **ret);
+
+#define IMPORT_BUFFER_SIZE (128U*1024U)

src/import/import-compress.c

@@ -3,6 +3,7 @@
 #include <stdlib.h>
 #include <string.h>
 
+#include "import-common.h"
 #include "import-compress.h"
 #include "log.h"
 #include "string-table.h"
@@ -148,7 +149,7 @@ int import_uncompress(ImportCompress *c, const void *data, size_t size, ImportCo
                 c->xz.avail_in = size;
 
                 while (c->xz.avail_in > 0) {
-                        uint8_t buffer[16 * 1024];
+                        uint8_t buffer[IMPORT_BUFFER_SIZE];
                         lzma_ret lzr;
 
                         c->xz.next_out = buffer;
@@ -172,7 +173,7 @@ int import_uncompress(ImportCompress *c, const void *data, size_t size, ImportCo
                 c->gzip.avail_in = size;
 
                 while (c->gzip.avail_in > 0) {
-                        uint8_t buffer[16 * 1024];
+                        uint8_t buffer[IMPORT_BUFFER_SIZE];
 
                         c->gzip.next_out = buffer;
                         c->gzip.avail_out = sizeof(buffer);
@@ -196,7 +197,7 @@ int import_uncompress(ImportCompress *c, const void *data, size_t size, ImportCo
                 c->bzip2.avail_in = size;
 
                 while (c->bzip2.avail_in > 0) {
-                        uint8_t buffer[16 * 1024];
+                        uint8_t buffer[IMPORT_BUFFER_SIZE];
 
                         c->bzip2.next_out = (char*) buffer;
                         c->bzip2.avail_out = sizeof(buffer);
@@ -222,7 +223,7 @@ int import_uncompress(ImportCompress *c, const void *data, size_t size, ImportCo
                 };
 
                 while (input.pos < input.size) {
-                        uint8_t buffer[16 * 1024];
+                        uint8_t buffer[IMPORT_BUFFER_SIZE];
                         ZSTD_outBuffer output = {
                                 .dst = buffer,
                                 .size = sizeof(buffer),
@@ -320,7 +321,7 @@ static int enlarge_buffer(void **buffer, size_t *buffer_size, size_t *buffer_all
         if (*buffer_allocated > *buffer_size)
                 return 0;
 
-        l = MAX(16*1024U, (*buffer_size * 2));
+        l = MAX(IMPORT_BUFFER_SIZE, (*buffer_size * 2));
         p = realloc(*buffer, l);
         if (!p)
                 return -ENOMEM;

src/import/import-raw.c

@@ -47,7 +47,7 @@ typedef struct RawImport {
 
         sd_event_source *input_event_source;
 
-        uint8_t buffer[16*1024];
+        uint8_t buffer[IMPORT_BUFFER_SIZE];
         size_t buffer_size;
 
         uint64_t written_compressed;

src/import/import-tar.c

@@ -49,7 +49,7 @@ typedef struct TarImport {
 
         sd_event_source *input_event_source;
 
-        uint8_t buffer[16*1024];
+        uint8_t buffer[IMPORT_BUFFER_SIZE];
         size_t buffer_size;
 
         uint64_t written_compressed;