On Wed, Feb 08, 2017 at 04:18:25PM -0800, Junio C Hamano wrote:
> > We wrote something similar at GitHub, too, but we never ended up using
> > it in production. We found that with a sane scheduler, it's not too big
> > a deal to just do maintenance once in a while.
>
> Thanks again for this. I've also been wondering about how effective
> a "concatenate packs without paying reachability penalty" would be.
For the sake of posterity, I'll include our patch at the end (sorry, not
chunked into nice readable commits; that never existed in the first
place).
> > I'm still not sure if it's worth making the fatal/non-fatal distinction.
> > Doing so is perhaps safer, but it does mean that somebody has to decide
> > which errors are important enough to block a retry totally, and which
> > are not. In theory, it would be safe to always _try_ and then the gc
> > process can decide when something is broken and abort. And all you've
> > wasted is some processing power each day.
>
> Yup, and somebody or something need to monitor so that repeated
> failures can be dealt with.
Yes. I think that part is probably outside the scope of Git. But if
auto-gc leaves gc.log lying around, it would be easy to visit each repo
and collect the various failures.
-- >8 --
This is the "pack-fast" patch, for reference. It applies on v2.6.5,
though I had to do some wiggling due to a few of our other custom
patches, so it's possible I introduced new bugs. It compiles, but I
didn't actually re-test the result. I _think_ the original at least
generated valid packs in all cases.
So I would certainly not recommend anybody run this. It's just a
possible base to work off of if anybody's interested in the topic. I
haven't looked at David's combine-packs at all to see if it is any less
gross. :)
---
Makefile | 1 +
builtin.h | 1 +
builtin/pack-fast.c | 618 +++++++++++++++++++++++++++++++++++
cache.h | 5 +
git.c | 1 +
pack-bitmap-write.c | 167 +++++++++-
pack-bitmap.c | 2 +-
pack-bitmap.h | 8 +
sha1_file.c | 4 +-
9 files changed, 792 insertions(+), 15 deletions(-)
diff --git a/Makefile b/Makefile
index 37e2d9e18..524b185ec 100644
--- a/Makefile
+++ b/Makefile
@@ -887,6 +887,7 @@ BUILTIN_OBJS += builtin/mv.o
BUILTIN_OBJS += builtin/name-rev.o
BUILTIN_OBJS += builtin/notes.o
BUILTIN_OBJS += builtin/pack-objects.o
+BUILTIN_OBJS += builtin/pack-fast.o
BUILTIN_OBJS += builtin/pack-redundant.o
BUILTIN_OBJS += builtin/pack-refs.o
BUILTIN_OBJS += builtin/patch-id.o
diff --git a/builtin.h b/builtin.h
index 79aaf0afe..df4e4d668 100644
--- a/builtin.h
+++ b/builtin.h
@@ -95,6 +95,7 @@ extern int cmd_mv(int argc, const char **argv, const char *prefix);
extern int cmd_name_rev(int argc, const char **argv, const char *prefix);
extern int cmd_notes(int argc, const char **argv, const char *prefix);
extern int cmd_pack_objects(int argc, const char **argv, const char *prefix);
+extern int cmd_pack_fast(int argc, const char **argv, const char *prefix);
extern int cmd_pack_redundant(int argc, const char **argv, const char *prefix);
extern int cmd_patch_id(int argc, const char **argv, const char *prefix);
extern int cmd_prune(int argc, const char **argv, const char *prefix);
diff --git a/builtin/pack-fast.c b/builtin/pack-fast.c
new file mode 100644
index 000000000..ad9f5e5f1
--- /dev/null
+++ b/builtin/pack-fast.c
@@ -0,0 +1,618 @@
+#include "builtin.h"
+#include "cache.h"
+#include "pack.h"
+#include "progress.h"
+#include "csum-file.h"
+#include "sha1-lookup.h"
+#include "parse-options.h"
+#include "tempfile.h"
+#include "pack-bitmap.h"
+#include "pack-revindex.h"
+
+static const char *pack_usage[] = {
+ N_("git pack-fast --quiet [options...] [base-name]"),
+ NULL
+};
+
+struct packwriter {
+ struct tempfile *tmp;
+ off_t total;
+ int fd;
+ uint32_t crc32;
+ unsigned do_crc;
+};
+
+static void packwriter_crc32_start(struct packwriter *w)
+{
+ w->crc32 = crc32(0, NULL, 0);
+ w->do_crc = 1;
+}
+
+static uint32_t packwriter_crc32_end(struct packwriter *w)
+{
+ w->do_crc = 0;
+ return w->crc32;
+}
+
+static void packwriter_write(struct packwriter *w, const void *buf, unsigned int count)
+{
+ if (w->do_crc)
+ w->crc32 = crc32(w->crc32, buf, count);
+ write_or_die(w->fd, buf, count);
+ w->total += count;
+}
+
+static off_t packwriter_total(struct packwriter *w)
+{
+ return w->total;
+}
+
+static void packwriter_init(struct packwriter *w)
+{
+ char tmpname[PATH_MAX];
+
+ w->fd = odb_mkstemp(tmpname, sizeof(tmpname), "pack/tmp_pack_XXXXXX");
+ w->total = 0;
+ w->do_crc = 0;
+ w->tmp = xcalloc(1, sizeof(*w->tmp));
+
+ register_tempfile(w->tmp, tmpname);
+}
+
+
+static int progress = 1;
+static struct progress *progress_state;
+static struct pack_idx_option pack_idx_opts;
+static const char *base_name = "pack-fast";
+static int skip_largest;
+static int write_bitmap_index = 1;
+
+static struct packed_git **all_packfiles;
+static unsigned int all_packfiles_nr;
+
+static struct pack_idx_entry **written_list;
+static unsigned int written_nr;
+
+struct write_slab {
+ struct write_slab *next;
+ unsigned int nr;
+
+ struct write_slab_entry {
+ struct pack_idx_entry idx;
+ enum object_type real_type;
+ } entries[];
+};
+
+static struct write_slab *written_slab_root;
+static struct write_slab *written_slab_current;
+
+static void add_to_write_list(
+ const unsigned char *sha1, off_t offset, uint32_t crc32,
+ enum object_type real_type)
+{
+ struct write_slab *slab = written_slab_current;
+ struct write_slab_entry *entry = &(slab->entries[slab->nr++]);
+
+ entry->real_type = real_type;
+ entry->idx.offset = offset;
+ entry->idx.crc32 = crc32;
+ hashcpy(entry->idx.sha1, sha1);
+}
+
+static void preallocate_write_slab(unsigned int num_entries)
+{
+ struct write_slab *slab = xmalloc(
+ sizeof(struct write_slab) +
+ num_entries * sizeof(struct write_slab_entry));
+
+ slab->next = NULL;
+ slab->nr = 0;
+
+ if (!written_slab_current) {
+ written_slab_current = slab;
+ written_slab_root = slab;
+ } else {
+ written_slab_current->next = slab;
+ written_slab_current = slab;
+ }
+}
+
+static struct skipped_object {
+ off_t skipped_offset;
+ off_t real_offset;
+} *skipped_list;
+static unsigned int skipped_nr;
+static unsigned int skipped_alloc;
+
+static void add_to_skipped_list(off_t skipped_offset, off_t real_offset)
+{
+ if (skipped_nr >= skipped_alloc) {
+ skipped_alloc = (skipped_alloc + 32) * 2;
+ REALLOC_ARRAY(skipped_list, skipped_alloc);
+ }
+
+ skipped_list[skipped_nr].skipped_offset = skipped_offset;
+ skipped_list[skipped_nr].real_offset = real_offset;
+ skipped_nr++;
+}
+
+static off_t find_real_offset_for_base(off_t skipped_offset)
+{
+ int lo = 0, hi = skipped_nr;
+ while (lo < hi) {
+ int mi = lo + ((hi - lo) / 2);
+ if (skipped_offset == skipped_list[mi].skipped_offset)
+ return skipped_list[mi].real_offset;
+ if (skipped_offset < skipped_list[mi].skipped_offset)
+ hi = mi;
+ else
+ lo = mi + 1;
+ }
+
+ return 0;
+}
+
+/*
+ * Record the offsets needed in our reused packfile chunks due to
+ * "gaps" where we omitted some objects.
+ */
+static struct reused_chunk {
+ off_t start;
+ off_t offset;
+} *reused_chunks;
+static int reused_chunks_nr;
+static int reused_chunks_alloc;
+
+static void record_reused_object(off_t where, off_t offset)
+{
+ if (reused_chunks_nr && reused_chunks[reused_chunks_nr-1].offset == offset)
+ return;
+
+ ALLOC_GROW(reused_chunks, reused_chunks_nr + 1,
+ reused_chunks_alloc);
+ reused_chunks[reused_chunks_nr].start = where;
+ reused_chunks[reused_chunks_nr].offset = offset;
+ reused_chunks_nr++;
+}
+
+/*
+ * Binary search to find the chunk that "where" is in. Note
+ * that we're not looking for an exact match, just the first
+ * chunk that contains it (which implicitly ends at the start
+ * of the next chunk.
+ */
+static off_t find_reused_offset(off_t where)
+{
+ int lo = 0, hi = reused_chunks_nr;
+ while (lo < hi) {
+ int mi = lo + ((hi - lo) / 2);
+ if (where == reused_chunks[mi].start)
+ return reused_chunks[mi].offset;
+ if (where < reused_chunks[mi].start)
+ hi = mi;
+ else
+ lo = mi + 1;
+ }
+
+ /*
+ * The first chunk starts at zero, so we can't have gone below
+ * there.
+ */
+ assert(lo);
+ return reused_chunks[lo-1].offset;
+}
+
+static uint32_t nth_packed_object_crc32(const struct packed_git *p, uint32_t nr)
+{
+ const uint32_t *index_crc = p->index_data;
+ index_crc += 2 + 256 + p->num_objects * (20/4) + nr;
+ return ntohl(*index_crc);
+}
+
+static void load_index_or_die(struct packed_git *p)
+{
+ if (open_pack_index(p) < 0)
+ die("failed to open index for '%s'", p->pack_name);
+
+ if (p->index_version != 2)
+ die("unsupported index version %d (fast-pack requires index v2)\n",
+ p->index_version);
+}
+
+static int sort_pack(const void *a_, const void *b_)
+{
+ struct packed_git *a = *((struct packed_git **)a_);
+ struct packed_git *b = *((struct packed_git **)b_);
+
+ if (a->mtime > b->mtime)
+ return 1;
+ else if (a->mtime == b->mtime)
+ return 0;
+ return -1;
+}
+
+static void find_packfiles(void)
+{
+ struct packed_git *p;
+ unsigned int n;
+
+ prepare_packed_git();
+
+ for (n = 0, p = packed_git; p; p = p->next) {
+ if (p->pack_local)
+ n++;
+ }
+
+ all_packfiles = xcalloc(n, sizeof(struct packed_git *));
+ all_packfiles_nr = n;
+
+ for (n = 0, p = packed_git; p; p = p->next) {
+ if (p->pack_local)
+ all_packfiles[n++] = p;
+ }
+
+ for (n = 1; n < all_packfiles_nr; ++n) {
+ if (all_packfiles[n]->pack_size > all_packfiles[0]->pack_size) {
+ struct packed_git *tmp = all_packfiles[0];
+ all_packfiles[0] = all_packfiles[n];
+ all_packfiles[n] = tmp;
+ }
+ }
+
+ qsort(all_packfiles + 1, all_packfiles_nr - 1, sizeof(struct packed_git *), sort_pack);
+}
+
+static int sha1_index__cmp(const void *a_, const void *b_)
+{
+ struct pack_idx_entry *a = *((struct pack_idx_entry **)a_);
+ struct pack_idx_entry *b = *((struct pack_idx_entry **)b_);
+ return hashcmp(a->sha1, b->sha1);
+}
+
+static const unsigned char *sha1_index__access(size_t pos, void *table)
+{
+ struct pack_idx_entry **index = table;
+ return index[pos]->sha1;
+}
+
+static void sha1_index_update(void)
+{
+ const unsigned int left_nr = written_nr;
+ const unsigned int right_nr = written_slab_current->nr;
+ const unsigned int total_nr = left_nr + right_nr;
+
+ struct pack_idx_entry **left = written_list;
+ struct pack_idx_entry **right = xmalloc(right_nr * sizeof(struct pack_idx_entry *));
+ struct pack_idx_entry **result = xmalloc(total_nr * sizeof(struct pack_idx_entry *));
+
+ unsigned int i, j, n;
+
+ for (j = 0; j < right_nr; ++j)
+ right[j] = (struct pack_idx_entry *)(&written_slab_current->entries[j]);
+
+ qsort(right, right_nr, sizeof(struct pack_idx_entry *), sha1_index__cmp);
+
+ for (i = j = n = 0; i < left_nr && j < right_nr; ++n) {
+ struct pack_idx_entry *a = left[i];
+ struct pack_idx_entry *b = right[j];
+
+ if (hashcmp(a->sha1, b->sha1) <= 0) {
+ result[n] = a;
+ i++;
+ } else {
+ result[n] = b;
+ j++;
+ }
+ }
+
+ for (; i < left_nr; ++n, ++i)
+ result[n] = left[i];
+
+ for (; j < right_nr; ++n, ++j)
+ result[n] = right[j];
+
+ free(written_list);
+ free(right);
+
+ written_list = result;
+ written_nr = total_nr;
+}
+
+static off_t sha1_index_find_offset(const unsigned char *sha1)
+{
+ int pos = sha1_pos(sha1, written_list, written_nr, sha1_index__access);
+ return (pos < 0) ? 0 : written_list[pos]->offset;
+}
+
+static void copy_pack_data(
+ struct packwriter *w,
+ struct packed_git *p,
+ struct pack_window **w_curs,
+ off_t offset,
+ off_t len)
+{
+ unsigned char *in;
+ unsigned long avail;
+
+ while (len) {
+ in = use_pack(p, w_curs, offset, &avail);
+ if (avail > len)
+ avail = (unsigned long)len;
+ packwriter_write(w, in, avail);
+ offset += avail;
+ len -= avail;
+ }
+}
+
+extern enum object_type packed_to_object_type(
+ struct packed_git *p, off_t obj_offset, enum object_type type,
+ struct pack_window **w_curs, off_t curpos);
+
+static int append_object_1(
+ struct revindex_entry *reventry,
+ struct packwriter *w,
+ struct packed_git *pack,
+ struct pack_window **w_curs,
+ enum object_type *real_type)
+{
+ const off_t offset = reventry[0].offset;
+ const off_t next = reventry[1].offset;
+
+ off_t cur;
+ enum object_type type;
+ unsigned long size;
+
+ record_reused_object(offset, offset - packwriter_total(w));
+
+ cur = offset;
+ type = unpack_object_header(pack, w_curs, &cur, &size);
+ assert(type >= 0);
+
+ if (write_bitmap_index)
+ *real_type = packed_to_object_type(pack, offset, type, w_curs, cur);
+
+ if (type == OBJ_OFS_DELTA) {
+ const off_t base_offset = get_delta_base(pack, w_curs, &cur, type, offset);
+ const off_t real_base_offset = find_real_offset_for_base(base_offset);
+ off_t fixed_offset = 0;
+
+ assert(base_offset != 0);
+
+ if (real_base_offset) {
+ fixed_offset = packwriter_total(w) - real_base_offset;
+ } else {
+ off_t fixup = find_reused_offset(offset) - find_reused_offset(base_offset);
+ if (fixup)
+ fixed_offset = offset - base_offset - fixup;
+ }
+
+ if (fixed_offset) {
+ unsigned char header[10], ofs_header[10];
+ unsigned i, len, ofs_len;
+
+ assert(fixed_offset > 0);
+ len = encode_in_pack_object_header(OBJ_OFS_DELTA, size, header);
+
+ i = sizeof(ofs_header) - 1;
+ ofs_header[i] = fixed_offset & 127;
+ while (fixed_offset >>= 7)
+ ofs_header[--i] = 128 | (--fixed_offset & 127);
+
+ ofs_len = sizeof(ofs_header) - i;
+
+ packwriter_write(w, header, len);
+ packwriter_write(w, ofs_header + sizeof(ofs_header) - ofs_len, ofs_len);
+ copy_pack_data(w, pack, w_curs, cur, next - cur);
+ return 1;
+ }
+
+ /* ...otherwise we have no fixup, and can write it verbatim */
+ }
+
+ copy_pack_data(w, pack, w_curs, offset, next - offset);
+ return 0;
+}
+
+static int copy_packfile(int from, struct packwriter *w)
+{
+ unsigned char buffer[8192];
+ struct stat st;
+ ssize_t to_read;
+
+ if (from < 0 || fstat(from, &st))
+ return -1;
+
+ posix_fadvise(from, 0, st.st_size, POSIX_FADV_SEQUENTIAL);
+ to_read = st.st_size - 20;
+
+ if (progress)
+ fprintf(stderr, "Copying main packfile...");
+
+ while (to_read) {
+ ssize_t r, cap = sizeof(buffer);
+
+ if (cap > to_read)
+ cap = to_read;
+
+ r = xread(from, buffer, cap);
+ if (r < 0)
+ return -1;
+
+ packwriter_write(w, buffer, r);
+ to_read -= r;
+ }
+
+ if (progress)
+ fprintf(stderr, " done.\n");
+ assert(to_read == 0);
+ return 0;
+}
+
+static void write_initial_packfile(struct packed_git *p, struct packwriter *w)
+{
+ unsigned int n;
+ int source_fd = git_open_noatime(p->pack_name);
+
+ if (copy_packfile(source_fd, w) < 0)
+ die_errno("failed to copy '%s'", p->pack_name);
+ close(source_fd);
+
+ load_index_or_die(p);
+ preallocate_write_slab(p->num_objects);
+
+ if (progress)
+ progress_state = start_progress("Indexing main packfile", p->num_objects);
+
+ for (n = 0; n < p->num_objects; ++n) {
+ const unsigned char *sha1 = nth_packed_object_sha1(p, n);
+ const off_t offset = nth_packed_object_offset(p, n);
+ const uint32_t crc32 = nth_packed_object_crc32(p, n);
+ add_to_write_list(sha1, offset, crc32, OBJ_BAD);
+ display_progress(progress_state, n + 1);
+ }
+
+ stop_progress(&progress_state);
+ close_pack_index(p);
+
+ written_list = xmalloc(p->num_objects * sizeof(struct packed_git *));
+ written_nr = p->num_objects;
+ for (n = 0; n < written_nr; ++n)
+ written_list[n] = (struct pack_idx_entry *)(&written_slab_current->entries[n]);
+}
+
+static void append_packfile(struct packed_git *p, struct packwriter *w)
+{
+ struct pack_window *w_curs = NULL;
+ struct pack_revindex *revidx;
+
+ unsigned int n;
+
+ load_index_or_die(p);
+ preallocate_write_slab(p->num_objects);
+ revidx = revindex_for_pack(p);
+
+ if (progress)
+ progress_state = start_progress("Appending packfile", p->num_objects);
+
+ for (n = 0; n < p->num_objects; ++n) {
+ struct revindex_entry *reventry = &revidx->revindex[n];
+ const unsigned char *sha1 = nth_packed_object_sha1(p, reventry[0].nr);
+ const off_t offset_in_pack = sha1_index_find_offset(sha1);
+
+ if (!offset_in_pack) {
+ const off_t offset = packwriter_total(w);
+
+ enum object_type real_type = OBJ_BAD;
+ uint32_t crc32;
+ int rewrite_header;
+
+ packwriter_crc32_start(w);
+ rewrite_header = append_object_1(reventry, w, p, &w_curs, &real_type);
+ crc32 = packwriter_crc32_end(w);
+
+ if (!rewrite_header && crc32 != nth_packed_object_crc32(p, reventry[0].nr))
+ die("crc32 check failed for %s", sha1_to_hex(sha1));
+
+ add_to_write_list(sha1, offset, crc32, real_type);
+ } else {
+ add_to_skipped_list(reventry[0].offset, offset_in_pack);
+ }
+
+ display_progress(progress_state, n + 1);
+ }
+
+ stop_progress(&progress_state);
+ unuse_pack(&w_curs);
+ close_pack_windows(p);
+ close_pack_index(p);
+
+ sha1_index_update();
+ skipped_nr = 0;
+ reused_chunks_nr = 0;
+}
+
+static void write_packs(void)
+{
+ struct packwriter w;
+ unsigned int i;
+
+ packwriter_init(&w);
+ write_initial_packfile(all_packfiles[0], &w);
+
+ for (i = 1; i < all_packfiles_nr; ++i)
+ append_packfile(all_packfiles[i], &w);
+
+ /* finalize pack */
+ {
+ unsigned char sha1[20];
+ struct strbuf tmpname = STRBUF_INIT;
+
+ fixup_pack_header_footer(w.fd, sha1, w.tmp->filename.buf, written_nr, NULL, 0);
+ close(w.fd);
+
+ strbuf_addf(&tmpname, "%s-", base_name);
+
+ finish_tmp_packfile(&tmpname, w.tmp->filename.buf,
+ written_list, written_nr,
+ &pack_idx_opts, sha1);
+
+ if (write_bitmap_index) {
+ strbuf_addf(&tmpname, "%s.bitmap", sha1_to_hex(sha1));
+ bitmap_rewrite_existing(
+ all_packfiles[0],
+ written_list, written_nr,
+ packwriter_total(&w),
+ sha1, tmpname.buf);
+ }
+
+ strbuf_release(&tmpname);
+ puts(sha1_to_hex(sha1));
+ }
+}
+
+void pack_fast_grow_typemaps(struct packed_git *p, struct ewah_bitmap **typemaps)
+{
+ uint32_t n;
+ size_t pos = p->num_objects;
+ struct write_slab *slab = written_slab_root;
+
+ assert(slab->nr == p->num_objects);
+ assert(slab->next);
+ slab = slab->next;
+
+ while (slab) {
+ for (n = 0; n < slab->nr; ++n) {
+ const enum object_type real_type = slab->entries[n].real_type;
+ assert(real_type >= OBJ_COMMIT && real_type <= OBJ_TAG);
+ ewah_set(typemaps[real_type - 1], pos++);
+ }
+ slab = slab->next;
+ }
+}
+
+int cmd_pack_fast(int argc, const char **argv, const char *prefix)
+{
+ struct option pack_fast_options[] = {
+ OPT_SET_INT('q', "quiet", &progress,
+ N_("do not show progress meter"), 0),
+ OPT_SET_INT(0, "progress", &progress,
+ N_("show progress meter"), 1),
+ OPT_BOOL(0, "skip-largest", &skip_largest,
+ N_("do not pack the largest packfile in the repository")),
+ OPT_END(),
+ };
+
+ reset_pack_idx_option(&pack_idx_opts);
+ progress = isatty(2);
+ argc = parse_options(argc, argv, prefix, pack_fast_options,
+ pack_usage, 0);
+
+ if (argc) {
+ base_name = argv[0];
+ argc--;
+ }
+
+ find_packfiles();
+ write_packs();
+ return 0;
+}
diff --git a/cache.h b/cache.h
index 6f53962bf..1a13961bd 100644
--- a/cache.h
+++ b/cache.h
@@ -1336,6 +1336,11 @@ extern void *unpack_entry(struct packed_git *, off_t, enum object_type *, unsign
extern unsigned long unpack_object_header_buffer(const unsigned char *buf, unsigned long len, enum object_type *type, unsigned long *sizep);
extern unsigned long get_size_from_delta(struct packed_git *, struct pack_window **, off_t);
extern int unpack_object_header(struct packed_git *, struct pack_window **, off_t *, unsigned long *);
+extern off_t get_delta_base(struct packed_git *p,
+ struct pack_window **w_curs,
+ off_t *curpos,
+ enum object_type type,
+ off_t delta_obj_offset);
/*
* Iterate over the files in the loose-object parts of the object
diff --git a/git.c b/git.c
index 40f9df089..d81bd4469 100644
--- a/git.c
+++ b/git.c
@@ -440,6 +440,7 @@ static struct cmd_struct commands[] = {
{ "name-rev", cmd_name_rev, RUN_SETUP },
{ "notes", cmd_notes, RUN_SETUP },
{ "pack-objects", cmd_pack_objects, RUN_SETUP },
+ { "pack-fast", cmd_pack_fast, RUN_SETUP },
{ "pack-redundant", cmd_pack_redundant, RUN_SETUP },
{ "pack-refs", cmd_pack_refs, RUN_SETUP },
{ "patch-id", cmd_patch_id },
diff --git a/pack-bitmap-write.c b/pack-bitmap-write.c
index c05d1386a..449715f02 100644
--- a/pack-bitmap-write.c
+++ b/pack-bitmap-write.c
@@ -505,23 +505,39 @@ void bitmap_writer_set_checksum(unsigned char *sha1)
hashcpy(writer.pack_checksum, sha1);
}
+static struct sha1file *bitmap_file_new(char *tmp_file, size_t len)
+{
+ int fd = odb_mkstemp(tmp_file, len, "pack/tmp_bitmap_XXXXXX");
+
+ if (fd < 0)
+ die_errno("unable to create '%s'", tmp_file);
+
+ return sha1fd(fd, tmp_file);
+}
+
+static void bitmap_file_close(struct sha1file *f, const char *tmp_file, const char *dest)
+{
+ sha1close(f, NULL, CSUM_FSYNC);
+
+ if (adjust_shared_perm(tmp_file))
+ die_errno("unable to make temporary bitmap file readable");
+
+ if (rename(tmp_file, dest))
+ die_errno("unable to rename temporary bitmap file to '%s'", dest);
+}
+
void bitmap_writer_finish(struct pack_idx_entry **index,
uint32_t index_nr,
const char *filename,
uint16_t options)
{
- static char tmp_file[PATH_MAX];
static uint16_t default_version = 1;
static uint16_t flags = BITMAP_OPT_FULL_DAG;
+ char tmp_file[PATH_MAX];
struct sha1file *f;
-
struct bitmap_disk_header header;
- int fd = odb_mkstemp(tmp_file, sizeof(tmp_file), "pack/tmp_bitmap_XXXXXX");
-
- if (fd < 0)
- die_errno("unable to create '%s'", tmp_file);
- f = sha1fd(fd, tmp_file);
+ f = bitmap_file_new(tmp_file, sizeof(tmp_file));
memcpy(header.magic, BITMAP_IDX_SIGNATURE, sizeof(BITMAP_IDX_SIGNATURE));
header.version = htons(default_version);
@@ -539,11 +555,138 @@ void bitmap_writer_finish(struct pack_idx_entry **index,
if (options & BITMAP_OPT_HASH_CACHE)
write_hash_cache(f, index, index_nr);
- sha1close(f, NULL, CSUM_FSYNC);
+ bitmap_file_close(f, tmp_file, filename);
+}
- if (adjust_shared_perm(tmp_file))
- die_errno("unable to make temporary bitmap file readable");
+static void *try_load_bitmap(struct packed_git *p, size_t *_size_out)
+{
+ void *reused_bitmap;
+ size_t reused_bitmap_size;
+
+ int fd;
+ struct stat st;
+ char *idx_name;
+
+ idx_name = pack_bitmap_filename(p);
+ fd = git_open_noatime(idx_name);
+ free(idx_name);
+
+ if (fd < 0)
+ return NULL;
+
+ if (fstat(fd, &st)) {
+ close(fd);
+ return NULL;
+ }
+
+ reused_bitmap_size = xsize_t(st.st_size);
+ reused_bitmap = xmmap(NULL, reused_bitmap_size, PROT_READ, MAP_PRIVATE, fd, 0);
+ close(fd);
+
+ *_size_out = reused_bitmap_size;
+ return reused_bitmap;
+}
+
+extern void pack_fast_grow_typemaps(struct packed_git *p, struct ewah_bitmap **typemaps);
+
+static size_t rewrite_type_maps(struct sha1file *f,
+ struct packed_git *p, unsigned char *original_map, size_t original_size, size_t pos)
+{
+ struct ewah_bitmap *typemaps[4];
+ int r, i;
+
+ for (i = 0; i < 4; ++i) {
+ typemaps[i] = ewah_pool_new();
+ r = ewah_read_mmap(typemaps[i], original_map + pos, original_size - pos);
+ if (r < 0)
+ die("failed to read bitmap index");
+ pos += r;
+ }
+
+ pack_fast_grow_typemaps(p, typemaps);
+
+ for (i = 0; i < 4; ++i) {
+ dump_bitmap(f, typemaps[i]);
+ ewah_pool_free(typemaps[i]);
+ }
+
+ return pos;
+}
+
+static size_t rewrite_bitmaps(struct sha1file *f,
+ struct packed_git *p, unsigned char *original_map, size_t original_size, size_t pos,
+ uint32_t entry_count, struct pack_idx_entry **index, uint32_t index_nr)
+{
+ uint32_t i;
+
+ for (i = 0; i < entry_count; ++i) {
+ const unsigned char *sha1;
+ uint32_t src_idx, src_buffer_len, total_len;
+ int new_idx;
+
+ src_idx = get_be32(original_map + pos);
+ pos += 4;
+
+ sha1 = nth_packed_object_sha1(p, src_idx);
+ new_idx = sha1_pos(sha1, index, index_nr, sha1_access);
+ sha1write_be32(f, (uint32_t)new_idx);
+
+ src_buffer_len = get_be32(original_map + pos + 2 + 4);
+ total_len = (3 * 4) + (src_buffer_len * 8);
+
+ sha1write(f, original_map + pos, 2 + total_len);
+ pos += 2 + total_len;
+
+ if (pos > original_size)
+ die("unexpected end of file");
+ }
+
+ return pos;
+}
+
+void bitmap_rewrite_existing(
+ struct packed_git *p,
+ struct pack_idx_entry **index,
+ uint32_t index_nr,
+ off_t pack_offset,
+ const unsigned char *pack_sha1,
+ const char *filename)
+{
+ char tmp_file[PATH_MAX];
+ struct sha1file *f;
+
+ unsigned char *original_map;
+ size_t original_size, pos = 0;
+ struct bitmap_disk_header header;
+
+ original_map = try_load_bitmap(p, &original_size);
+ if (!original_map || original_size < sizeof(header) + 20)
+ return;
+
+ memcpy(&header, original_map, sizeof(header));
+ hashcpy(header.checksum, pack_sha1);
+
+ if (memcmp(header.magic, BITMAP_IDX_SIGNATURE, sizeof(BITMAP_IDX_SIGNATURE)) != 0)
+ die("existing bitmap for '%s' is corrupted", p->pack_name);
+
+ if (ntohs(header.version) != 1)
+ die("existing bitmap for '%s' has an unsupported version", p->pack_name);
+
+ f = bitmap_file_new(tmp_file, sizeof(tmp_file));
+
+ sha1write(f, &header, sizeof(header));
+ pos = sizeof(header);
+ pos = rewrite_type_maps(f, p, original_map, original_size, pos);
+ pos = rewrite_bitmaps(f, p, original_map, original_size, pos,
+ ntohl(header.entry_count), index, index_nr);
+
+ if (ntohs(header.options) & BITMAP_OPT_HASH_CACHE) {
+ uint32_t i, zero = 0;
+ sha1write(f, original_map + pos, p->num_objects * 4);
+ for (i = p->num_objects; i < index_nr; ++i)
+ sha1write(f, &zero, 4);
+ pos += (p->num_objects * 4);
+ }
- if (rename(tmp_file, filename))
- die_errno("unable to rename temporary bitmap file to '%s'", filename);
+ bitmap_file_close(f, tmp_file, filename);
}
diff --git a/pack-bitmap.c b/pack-bitmap.c
index 637770af8..ee361fa6a 100644
--- a/pack-bitmap.c
+++ b/pack-bitmap.c
@@ -250,7 +250,7 @@ static int load_bitmap_entries_v1(struct bitmap_index *index)
return 0;
}
-static char *pack_bitmap_filename(struct packed_git *p)
+char *pack_bitmap_filename(struct packed_git *p)
{
char *idx_name;
int len;
diff --git a/pack-bitmap.h b/pack-bitmap.h
index 0adcef77b..398523dbb 100644
--- a/pack-bitmap.h
+++ b/pack-bitmap.h
@@ -34,6 +34,7 @@ typedef int (*show_reachable_fn)(
struct packed_git *found_pack,
off_t found_offset);
+char *pack_bitmap_filename(struct packed_git *p);
int prepare_bitmap_git(void);
void count_bitmap_commit_list(uint32_t *commits, uint32_t *trees, uint32_t *blobs, uint32_t *tags);
void traverse_bitmap_commit_list(show_reachable_fn show_reachable);
@@ -53,5 +54,12 @@ void bitmap_writer_finish(struct pack_idx_entry **index,
uint32_t index_nr,
const char *filename,
uint16_t options);
+void bitmap_rewrite_existing(
+ struct packed_git *p,
+ struct pack_idx_entry **index,
+ uint32_t index_nr,
+ off_t pack_offset,
+ const unsigned char *pack_sha1,
+ const char *filename);
#endif
diff --git a/sha1_file.c b/sha1_file.c
index 72289696d..bcd447f16 100644
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -1821,7 +1821,7 @@ unsigned long get_size_from_delta(struct packed_git *p,
return get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
}
-static off_t get_delta_base(struct packed_git *p,
+off_t get_delta_base(struct packed_git *p,
struct pack_window **w_curs,
off_t *curpos,
enum object_type type,
@@ -1936,7 +1936,7 @@ static int retry_bad_packed_offset(struct packed_git *p, off_t obj_offset)
#define POI_STACK_PREALLOC 64
-static enum object_type packed_to_object_type(struct packed_git *p,
+enum object_type packed_to_object_type(struct packed_git *p,
off_t obj_offset,
enum object_type type,
struct pack_window **w_curs,