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* Copyright (c) 2011, Google Inc.
#include "cache.h"
#include "bulk-checkin.h"
#include "lockfile.h"
#include "repository.h"
#include "csum-file.h"
#include "pack.h"
#include "strbuf.h"
#include "string-list.h"
#include "tmp-objdir.h"
#include "packfile.h"
#include "object-store.h"
static int odb_transaction_nesting;
static struct tmp_objdir *bulk_fsync_objdir;
static struct bulk_checkin_packfile {
char *pack_tmp_name;
struct hashfile *f;
off_t offset;
struct pack_idx_option pack_idx_opts;
struct pack_idx_entry **written;
uint32_t alloc_written;
uint32_t nr_written;
} bulk_checkin_packfile;
static void finish_tmp_packfile(struct strbuf *basename,
const char *pack_tmp_name,
struct pack_idx_entry **written_list,
uint32_t nr_written,
struct pack_idx_option *pack_idx_opts,
unsigned char hash[])
char *idx_tmp_name = NULL;
stage_tmp_packfiles(basename, pack_tmp_name, written_list, nr_written,
NULL, pack_idx_opts, hash, &idx_tmp_name);
rename_tmp_packfile_idx(basename, &idx_tmp_name);
static void flush_bulk_checkin_packfile(struct bulk_checkin_packfile *state)
unsigned char hash[GIT_MAX_RAWSZ];
struct strbuf packname = STRBUF_INIT;
int i;
if (!state->f)
if (state->nr_written == 0) {
goto clear_exit;
} else if (state->nr_written == 1) {
finalize_hashfile(state->f, hash, FSYNC_COMPONENT_PACK,
} else {
int fd = finalize_hashfile(state->f, hash, FSYNC_COMPONENT_PACK, 0);
fixup_pack_header_footer(fd, hash, state->pack_tmp_name,
state->nr_written, hash,
strbuf_addf(&packname, "%s/pack/pack-%s.", get_object_directory(),
finish_tmp_packfile(&packname, state->pack_tmp_name,
state->written, state->nr_written,
&state->pack_idx_opts, hash);
for (i = 0; i < state->nr_written; i++)
memset(state, 0, sizeof(*state));
/* Make objects we just wrote available to ourselves */
* Cleanup after batch-mode fsync_object_files.
static void flush_batch_fsync(void)
struct strbuf temp_path = STRBUF_INIT;
struct tempfile *temp;
if (!bulk_fsync_objdir)
* Issue a full hardware flush against a temporary file to ensure
* that all objects are durable before any renames occur. The code in
* fsync_loose_object_bulk_checkin has already issued a writeout
* request, but it has not flushed any writeback cache in the storage
* hardware or any filesystem logs. This fsync call acts as a barrier
* to ensure that the data in each new object file is durable before
* the final name is visible.
strbuf_addf(&temp_path, "%s/bulk_fsync_XXXXXX", get_object_directory());
temp = xmks_tempfile(temp_path.buf);
fsync_or_die(get_tempfile_fd(temp), get_tempfile_path(temp));
* Make the object files visible in the primary ODB after their data is
* fully durable.
bulk_fsync_objdir = NULL;
static int already_written(struct bulk_checkin_packfile *state, struct object_id *oid)
int i;
/* The object may already exist in the repository */
if (has_object_file(oid))
return 1;
/* Might want to keep the list sorted */
for (i = 0; i < state->nr_written; i++)
if (oideq(&state->written[i]->oid, oid))
return 1;
/* This is a new object we need to keep */
return 0;
* Read the contents from fd for size bytes, streaming it to the
* packfile in state while updating the hash in ctx. Signal a failure
* by returning a negative value when the resulting pack would exceed
* the pack size limit and this is not the first object in the pack,
* so that the caller can discard what we wrote from the current pack
* by truncating it and opening a new one. The caller will then call
* us again after rewinding the input fd.
* The already_hashed_to pointer is kept untouched by the caller to
* make sure we do not hash the same byte when we are called
* again. This way, the caller does not have to checkpoint its hash
* status before calling us just in case we ask it to call us again
* with a new pack.
static int stream_to_pack(struct bulk_checkin_packfile *state,
git_hash_ctx *ctx, off_t *already_hashed_to,
int fd, size_t size, enum object_type type,
const char *path, unsigned flags)
git_zstream s;
unsigned char ibuf[16384];
unsigned char obuf[16384];
unsigned hdrlen;
int status = Z_OK;
int write_object = (flags & HASH_WRITE_OBJECT);
off_t offset = 0;
git_deflate_init(&s, pack_compression_level);
hdrlen = encode_in_pack_object_header(obuf, sizeof(obuf), type, size);
s.next_out = obuf + hdrlen;
s.avail_out = sizeof(obuf) - hdrlen;
while (status != Z_STREAM_END) {
if (size && !s.avail_in) {
ssize_t rsize = size < sizeof(ibuf) ? size : sizeof(ibuf);
ssize_t read_result = read_in_full(fd, ibuf, rsize);
if (read_result < 0)
die_errno("failed to read from '%s'", path);
if (read_result != rsize)
die("failed to read %d bytes from '%s'",
(int)rsize, path);
offset += rsize;
if (*already_hashed_to < offset) {
size_t hsize = offset - *already_hashed_to;
if (rsize < hsize)
hsize = rsize;
if (hsize)
the_hash_algo->update_fn(ctx, ibuf, hsize);
*already_hashed_to = offset;
s.next_in = ibuf;
s.avail_in = rsize;
size -= rsize;
status = git_deflate(&s, size ? 0 : Z_FINISH);
if (!s.avail_out || status == Z_STREAM_END) {
if (write_object) {
size_t written = s.next_out - obuf;
/* would we bust the size limit? */
if (state->nr_written &&
pack_size_limit_cfg &&
pack_size_limit_cfg < state->offset + written) {
return -1;
hashwrite(state->f, obuf, written);
state->offset += written;
s.next_out = obuf;
s.avail_out = sizeof(obuf);
switch (status) {
case Z_OK:
die("unexpected deflate failure: %d", status);
return 0;
/* Lazily create backing packfile for the state */
static void prepare_to_stream(struct bulk_checkin_packfile *state,
unsigned flags)
if (!(flags & HASH_WRITE_OBJECT) || state->f)
state->f = create_tmp_packfile(&state->pack_tmp_name);
/* Pretend we are going to write only one object */
state->offset = write_pack_header(state->f, 1);
if (!state->offset)
die_errno("unable to write pack header");
static int deflate_to_pack(struct bulk_checkin_packfile *state,
struct object_id *result_oid,
int fd, size_t size,
enum object_type type, const char *path,
unsigned flags)
off_t seekback, already_hashed_to;
git_hash_ctx ctx;
unsigned char obuf[16384];
unsigned header_len;
struct hashfile_checkpoint checkpoint = {0};
struct pack_idx_entry *idx = NULL;
seekback = lseek(fd, 0, SEEK_CUR);
if (seekback == (off_t) -1)
return error("cannot find the current offset");
header_len = format_object_header((char *)obuf, sizeof(obuf),
type, size);
the_hash_algo->update_fn(&ctx, obuf, header_len);
/* Note: idx is non-NULL when we are writing */
if ((flags & HASH_WRITE_OBJECT) != 0)
already_hashed_to = 0;
while (1) {
prepare_to_stream(state, flags);
if (idx) {
hashfile_checkpoint(state->f, &checkpoint);
idx->offset = state->offset;
if (!stream_to_pack(state, &ctx, &already_hashed_to,
fd, size, type, path, flags))
* Writing this object to the current pack will make
* it too big; we need to truncate it, start a new
* pack, and write into it.
if (!idx)
BUG("should not happen");
hashfile_truncate(state->f, &checkpoint);
state->offset = checkpoint.offset;
if (lseek(fd, seekback, SEEK_SET) == (off_t) -1)
return error("cannot seek back");
the_hash_algo->final_oid_fn(result_oid, &ctx);
if (!idx)
return 0;
idx->crc32 = crc32_end(state->f);
if (already_written(state, result_oid)) {
hashfile_truncate(state->f, &checkpoint);
state->offset = checkpoint.offset;
} else {
oidcpy(&idx->oid, result_oid);
state->nr_written + 1,
state->written[state->nr_written++] = idx;
return 0;
void prepare_loose_object_bulk_checkin(void)
* We lazily create the temporary object directory
* the first time an object might be added, since
* callers may not know whether any objects will be
* added at the time they call begin_odb_transaction.
if (!odb_transaction_nesting || bulk_fsync_objdir)
bulk_fsync_objdir = tmp_objdir_create("bulk-fsync");
if (bulk_fsync_objdir)
tmp_objdir_replace_primary_odb(bulk_fsync_objdir, 0);
void fsync_loose_object_bulk_checkin(int fd, const char *filename)
* If we have an active ODB transaction, we issue a call that
* cleans the filesystem page cache but avoids a hardware flush
* command. Later on we will issue a single hardware flush
* before renaming the objects to their final names as part of
* flush_batch_fsync.
if (!bulk_fsync_objdir ||
git_fsync(fd, FSYNC_WRITEOUT_ONLY) < 0) {
if (errno == ENOSYS)
warning(_("core.fsyncMethod = batch is unsupported on this platform"));
fsync_or_die(fd, filename);
int index_bulk_checkin(struct object_id *oid,
int fd, size_t size, enum object_type type,
const char *path, unsigned flags)
int status = deflate_to_pack(&bulk_checkin_packfile, oid, fd, size, type,
path, flags);
if (!odb_transaction_nesting)
return status;
void begin_odb_transaction(void)
odb_transaction_nesting += 1;
void flush_odb_transaction(void)
void end_odb_transaction(void)
odb_transaction_nesting -= 1;
if (odb_transaction_nesting < 0)
BUG("Unbalanced ODB transaction nesting");
if (odb_transaction_nesting)