Re: [PATCH v2 2/3] core.fsync: introduce granular fsync control
From: Patrick Steinhardt <hidden>
Date: 2021-12-07 11:54:17
On Tue, Dec 07, 2021 at 02:46:50AM +0000, Neeraj Singh via GitGitGadget wrote:
From: Neeraj Singh <redacted>
[snip]
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diff --git a/builtin/index-pack.c b/builtin/index-pack.c index c23d01de7dc..c32534c13b4 100644 --- a/builtin/index-pack.c +++ b/builtin/index-pack.c@@ -1286,7 +1286,7 @@ static void conclude_pack(int fix_thin_pack, const char *curr_pack, unsigned cha nr_objects - nr_objects_initial); stop_progress_msg(&progress, msg.buf); strbuf_release(&msg); - finalize_hashfile(f, tail_hash, 0); + finalize_hashfile(f, tail_hash, FSYNC_COMPONENT_PACK, 0); hashcpy(read_hash, pack_hash); fixup_pack_header_footer(output_fd, pack_hash, curr_pack, nr_objects,@@ -1508,7 +1508,7 @@ static void final(const char *final_pack_name, const char *curr_pack_name, if (!from_stdin) { close(input_fd); } else { - fsync_or_die(output_fd, curr_pack_name); + fsync_component_or_die(FSYNC_COMPONENT_PACK, output_fd, curr_pack_name); err = close(output_fd); if (err) die_errno(_("error while closing pack file"));diff --git a/builtin/pack-objects.c b/builtin/pack-objects.c index 857be7826f3..916c55d6ce9 100644 --- a/builtin/pack-objects.c +++ b/builtin/pack-objects.c@@ -1204,11 +1204,13 @@ static void write_pack_file(void) * If so, rewrite it like in fast-import */ if (pack_to_stdout) { - finalize_hashfile(f, hash, CSUM_HASH_IN_STREAM | CSUM_CLOSE); + finalize_hashfile(f, hash, FSYNC_COMPONENT_NONE, + CSUM_HASH_IN_STREAM | CSUM_CLOSE);
It doesn't have any effect here given that we don't sync at all when writing to stdout, but I wonder whether we should set up the component correctly regardless of that such that it makes for a less confusing read. [snip]
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diff --git a/config.c b/config.c index c3410b8a868..29c867aab03 100644 --- a/config.c +++ b/config.c@@ -1213,6 +1213,73 @@ static int git_parse_maybe_bool_text(const char *value) return -1; } +static const struct fsync_component_entry { + const char *name; + enum fsync_component component_bits; +} fsync_component_table[] = { + { "loose-object", FSYNC_COMPONENT_LOOSE_OBJECT }, + { "pack", FSYNC_COMPONENT_PACK }, + { "pack-metadata", FSYNC_COMPONENT_PACK_METADATA }, + { "commit-graph", FSYNC_COMPONENT_COMMIT_GRAPH }, + { "objects", FSYNC_COMPONENTS_OBJECTS }, + { "default", FSYNC_COMPONENTS_DEFAULT }, + { "all", FSYNC_COMPONENTS_ALL }, +}; + +static enum fsync_component parse_fsync_components(const char *var, const char *string) +{ + enum fsync_component output = 0; + + if (!strcmp(string, "none")) + return output; + + while (string) { + int i; + size_t len; + const char *ep; + int negated = 0; + int found = 0; + + string = string + strspn(string, ", \t\n\r"); + ep = strchrnul(string, ','); + len = ep - string; + + if (*string == '-') { + negated = 1; + string++; + len--; + if (!len) + warning(_("invalid value for variable %s"), var); + } + + if (!len) + break; + + for (i = 0; i < ARRAY_SIZE(fsync_component_table); ++i) { + const struct fsync_component_entry *entry = &fsync_component_table[i]; + + if (strncmp(entry->name, string, len)) + continue; + + found = 1; + if (negated) + output &= ~entry->component_bits; + else + output |= entry->component_bits; + } + + if (!found) { + char *component = xstrndup(string, len); + warning(_("unknown %s value '%s'"), var, component); + free(component); + } + + string = ep; + } + + return output; +} + int git_parse_maybe_bool(const char *value) { int v = git_parse_maybe_bool_text(value);@@ -1490,6 +1557,13 @@ static int git_default_core_config(const char *var, const char *value, void *cb) return 0; } + if (!strcmp(var, "core.fsync")) { + if (!value) + return config_error_nonbool(var); + fsync_components = parse_fsync_components(var, value); + return 0; + } + if (!strcmp(var, "core.fsyncmethod")) { if (!value) return config_error_nonbool(var);@@ -1503,7 +1577,7 @@ static int git_default_core_config(const char *var, const char *value, void *cb) } if (!strcmp(var, "core.fsyncobjectfiles")) { - fsync_object_files = git_config_bool(var, value); + warning(_("core.fsyncobjectfiles is deprecated; use core.fsync instead")); return 0; }
Shouldn't we continue to support this for now such that users can migrate from the old, deprecated value first before we start to ignore it? Patrick
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diff --git a/csum-file.c b/csum-file.c index 26e8a6df44e..59ef3398ca2 100644 --- a/csum-file.c +++ b/csum-file.c@@ -58,7 +58,8 @@ static void free_hashfile(struct hashfile *f) free(f); } -int finalize_hashfile(struct hashfile *f, unsigned char *result, unsigned int flags) +int finalize_hashfile(struct hashfile *f, unsigned char *result, + enum fsync_component component, unsigned int flags) { int fd;@@ -69,7 +70,7 @@ int finalize_hashfile(struct hashfile *f, unsigned char *result, unsigned int fl if (flags & CSUM_HASH_IN_STREAM) flush(f, f->buffer, the_hash_algo->rawsz); if (flags & CSUM_FSYNC) - fsync_or_die(f->fd, f->name); + fsync_component_or_die(component, f->fd, f->name); if (flags & CSUM_CLOSE) { if (close(f->fd)) die_errno("%s: sha1 file error on close", f->name);diff --git a/csum-file.h b/csum-file.h index 291215b34eb..0d29f528fbc 100644 --- a/csum-file.h +++ b/csum-file.h@@ -1,6 +1,7 @@ #ifndef CSUM_FILE_H #define CSUM_FILE_H +#include "cache.h" #include "hash.h" struct progress;@@ -38,7 +39,7 @@ int hashfile_truncate(struct hashfile *, struct hashfile_checkpoint *); struct hashfile *hashfd(int fd, const char *name); struct hashfile *hashfd_check(const char *name); struct hashfile *hashfd_throughput(int fd, const char *name, struct progress *tp); -int finalize_hashfile(struct hashfile *, unsigned char *, unsigned int); +int finalize_hashfile(struct hashfile *, unsigned char *, enum fsync_component, unsigned int); void hashwrite(struct hashfile *, const void *, unsigned int); void hashflush(struct hashfile *f); void crc32_begin(struct hashfile *);diff --git a/environment.c b/environment.c index f9140e842cf..09905adecf9 100644 --- a/environment.c +++ b/environment.c@@ -42,6 +42,7 @@ const char *git_hooks_path; int zlib_compression_level = Z_BEST_SPEED; int pack_compression_level = Z_DEFAULT_COMPRESSION; enum fsync_method fsync_method = FSYNC_METHOD_DEFAULT; +enum fsync_component fsync_components = FSYNC_COMPONENTS_DEFAULT; size_t packed_git_window_size = DEFAULT_PACKED_GIT_WINDOW_SIZE; size_t packed_git_limit = DEFAULT_PACKED_GIT_LIMIT; size_t delta_base_cache_limit = 96 * 1024 * 1024;diff --git a/midx.c b/midx.c index 837b46b2af5..882f91f7d57 100644 --- a/midx.c +++ b/midx.c@@ -1406,7 +1406,8 @@ static int write_midx_internal(const char *object_dir, write_midx_header(f, get_num_chunks(cf), ctx.nr - dropped_packs); write_chunkfile(cf, &ctx); - finalize_hashfile(f, midx_hash, CSUM_FSYNC | CSUM_HASH_IN_STREAM); + finalize_hashfile(f, midx_hash, FSYNC_COMPONENT_PACK_METADATA, + CSUM_FSYNC | CSUM_HASH_IN_STREAM); free_chunkfile(cf); if (flags & (MIDX_WRITE_REV_INDEX | MIDX_WRITE_BITMAP))diff --git a/object-file.c b/object-file.c index eb972cdccd2..9d9c4a39e85 100644 --- a/object-file.c +++ b/object-file.c@@ -1809,8 +1809,7 @@ int hash_object_file(const struct git_hash_algo *algo, const void *buf, /* Finalize a file on disk, and close it. */ static void close_loose_object(int fd) { - if (fsync_object_files) - fsync_or_die(fd, "loose object file"); + fsync_component_or_die(FSYNC_COMPONENT_LOOSE_OBJECT, fd, "loose object file"); if (close(fd) != 0) die_errno(_("error when closing loose object file")); }diff --git a/pack-bitmap-write.c b/pack-bitmap-write.c index 9c55c1531e1..c16e43d1669 100644 --- a/pack-bitmap-write.c +++ b/pack-bitmap-write.c@@ -719,7 +719,8 @@ void bitmap_writer_finish(struct pack_idx_entry **index, if (options & BITMAP_OPT_HASH_CACHE) write_hash_cache(f, index, index_nr); - finalize_hashfile(f, NULL, CSUM_HASH_IN_STREAM | CSUM_FSYNC | CSUM_CLOSE); + finalize_hashfile(f, NULL, FSYNC_COMPONENT_PACK_METADATA, + CSUM_HASH_IN_STREAM | CSUM_FSYNC | CSUM_CLOSE); if (adjust_shared_perm(tmp_file.buf)) die_errno("unable to make temporary bitmap file readable");diff --git a/pack-write.c b/pack-write.c index a5846f3a346..51812cb1299 100644 --- a/pack-write.c +++ b/pack-write.c@@ -159,9 +159,9 @@ const char *write_idx_file(const char *index_name, struct pack_idx_entry **objec } hashwrite(f, sha1, the_hash_algo->rawsz); - finalize_hashfile(f, NULL, CSUM_HASH_IN_STREAM | CSUM_CLOSE | - ((opts->flags & WRITE_IDX_VERIFY) - ? 0 : CSUM_FSYNC)); + finalize_hashfile(f, NULL, FSYNC_COMPONENT_PACK_METADATA, + CSUM_HASH_IN_STREAM | CSUM_CLOSE | + ((opts->flags & WRITE_IDX_VERIFY) ? 0 : CSUM_FSYNC)); return index_name; }@@ -281,8 +281,9 @@ const char *write_rev_file_order(const char *rev_name, if (rev_name && adjust_shared_perm(rev_name) < 0) die(_("failed to make %s readable"), rev_name); - finalize_hashfile(f, NULL, CSUM_HASH_IN_STREAM | CSUM_CLOSE | - ((flags & WRITE_IDX_VERIFY) ? 0 : CSUM_FSYNC)); + finalize_hashfile(f, NULL, FSYNC_COMPONENT_PACK_METADATA, + CSUM_HASH_IN_STREAM | CSUM_CLOSE | + ((flags & WRITE_IDX_VERIFY) ? 0 : CSUM_FSYNC)); return rev_name; }@@ -390,7 +391,7 @@ void fixup_pack_header_footer(int pack_fd, the_hash_algo->final_fn(partial_pack_hash, &old_hash_ctx); the_hash_algo->final_fn(new_pack_hash, &new_hash_ctx); write_or_die(pack_fd, new_pack_hash, the_hash_algo->rawsz); - fsync_or_die(pack_fd, pack_name); + fsync_component_or_die(FSYNC_COMPONENT_PACK, pack_fd, pack_name); } char *index_pack_lockfile(int ip_out, int *is_well_formed)diff --git a/read-cache.c b/read-cache.c index f3986596623..f3539681f49 100644 --- a/read-cache.c +++ b/read-cache.c@@ -3060,7 +3060,7 @@ static int do_write_index(struct index_state *istate, struct tempfile *tempfile, return -1; } - finalize_hashfile(f, istate->oid.hash, CSUM_HASH_IN_STREAM); + finalize_hashfile(f, istate->oid.hash, FSYNC_COMPONENT_NONE, CSUM_HASH_IN_STREAM); if (close_tempfile_gently(tempfile)) { error(_("could not close '%s'"), get_tempfile_path(tempfile)); return -1;-- gitgitgadget
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