X-Git-Url: http://review.tizen.org/git/?a=blobdiff_plain;f=read-cache.c;h=29144cf879e795c3f5415cd5dd50f53a5dfb0cac;hb=HEAD;hp=7b1354d7590a70ecbd6e508bdd95eafd4793efcc;hpb=63b33047c1428dbf4f480b384962c6c8c0e841dd;p=platform%2Fupstream%2Fgit.git

diff --git a/read-cache.c b/read-cache.c
index 7b1354d..29144cf 100644
--- a/read-cache.c
+++ b/read-cache.c
@@ -3,7 +3,6 @@
  *
  * Copyright (C) Linus Torvalds, 2005
  */
-#define NO_THE_INDEX_COMPATIBILITY_MACROS
 #include "cache.h"
 #include "config.h"
 #include "diff.h"
@@ -18,11 +17,14 @@
 #include "commit.h"
 #include "blob.h"
 #include "resolve-undo.h"
+#include "run-command.h"
 #include "strbuf.h"
 #include "varint.h"
 #include "split-index.h"
 #include "utf8.h"
 #include "fsmonitor.h"
+#include "thread-utils.h"
+#include "progress.h"
 
 /* Mask for the name length in ce_flags in the on-disk index */
 
@@ -43,6 +45,8 @@
 #define CACHE_EXT_LINK 0x6c696e6b	  /* "link" */
 #define CACHE_EXT_UNTRACKED 0x554E5452	  /* "UNTR" */
 #define CACHE_EXT_FSMONITOR 0x46534D4E	  /* "FSMN" */
+#define CACHE_EXT_ENDOFINDEXENTRIES 0x454F4945	/* "EOIE" */
+#define CACHE_EXT_INDEXENTRYOFFSETTABLE 0x49454F54 /* "IEOT" */
 
 /* changes that can be kept in $GIT_DIR/index (basically all extensions) */
 #define EXTMASK (RESOLVE_UNDO_CHANGED | CACHE_TREE_CHANGED | \
@@ -85,13 +89,14 @@ static struct mem_pool *find_mem_pool(struct index_state *istate)
 	else
 		pool_ptr = &istate->ce_mem_pool;
 
-	if (!*pool_ptr)
-		mem_pool_init(pool_ptr, 0);
+	if (!*pool_ptr) {
+		*pool_ptr = xmalloc(sizeof(**pool_ptr));
+		mem_pool_init(*pool_ptr, 0);
+	}
 
 	return *pool_ptr;
 }
 
-struct index_state the_index;
 static const char *alternate_index_output;
 
 static void set_index_entry(struct index_state *istate, int nr, struct cache_entry *ce)
@@ -192,7 +197,7 @@ int match_stat_data(const struct stat_data *sd, struct stat *st)
  * cache, ie the parts that aren't tracked by GIT, and only used
  * to validate the cache.
  */
-void fill_stat_cache_info(struct cache_entry *ce, struct stat *st)
+void fill_stat_cache_info(struct index_state *istate, struct cache_entry *ce, struct stat *st)
 {
 	fill_stat_data(&ce->ce_stat_data, st);
 
@@ -201,19 +206,21 @@ void fill_stat_cache_info(struct cache_entry *ce, struct stat *st)
 
 	if (S_ISREG(st->st_mode)) {
 		ce_mark_uptodate(ce);
-		mark_fsmonitor_valid(ce);
+		mark_fsmonitor_valid(istate, ce);
 	}
 }
 
-static int ce_compare_data(const struct cache_entry *ce, struct stat *st)
+static int ce_compare_data(struct index_state *istate,
+			   const struct cache_entry *ce,
+			   struct stat *st)
 {
 	int match = -1;
 	int fd = git_open_cloexec(ce->name, O_RDONLY);
 
 	if (fd >= 0) {
 		struct object_id oid;
-		if (!index_fd(&oid, fd, st, OBJ_BLOB, ce->name, 0))
-			match = oidcmp(&oid, &ce->oid);
+		if (!index_fd(istate, &oid, fd, st, OBJ_BLOB, ce->name, 0))
+			match = !oideq(&oid, &ce->oid);
 		/* index_fd() closed the file descriptor already */
 	}
 	return match;
@@ -254,14 +261,16 @@ static int ce_compare_gitlink(const struct cache_entry *ce)
 	 */
 	if (resolve_gitlink_ref(ce->name, "HEAD", &oid) < 0)
 		return 0;
-	return oidcmp(&oid, &ce->oid);
+	return !oideq(&oid, &ce->oid);
 }
 
-static int ce_modified_check_fs(const struct cache_entry *ce, struct stat *st)
+static int ce_modified_check_fs(struct index_state *istate,
+				const struct cache_entry *ce,
+				struct stat *st)
 {
 	switch (st->st_mode & S_IFMT) {
 	case S_IFREG:
-		if (ce_compare_data(ce, st))
+		if (ce_compare_data(istate, ce, st))
 			return DATA_CHANGED;
 		break;
 	case S_IFLNK:
@@ -308,7 +317,7 @@ static int ce_match_stat_basic(const struct cache_entry *ce, struct stat *st)
 			changed |= DATA_CHANGED;
 		return changed;
 	default:
-		die("internal error: ce_mode is %o", ce->ce_mode);
+		BUG("unsupported ce_mode: %o", ce->ce_mode);
 	}
 
 	changed |= match_stat_data(&ce->ce_stat_data, st);
@@ -337,7 +346,7 @@ static int is_racy_stat(const struct index_state *istate,
 		);
 }
 
-static int is_racy_timestamp(const struct index_state *istate,
+int is_racy_timestamp(const struct index_state *istate,
 			     const struct cache_entry *ce)
 {
 	return (!S_ISGITLINK(ce->ce_mode) &&
@@ -407,7 +416,7 @@ int ie_match_stat(struct index_state *istate,
 		if (assume_racy_is_modified)
 			changed |= DATA_CHANGED;
 		else
-			changed |= ce_modified_check_fs(ce, st);
+			changed |= ce_modified_check_fs(istate, ce, st);
 	}
 
 	return changed;
@@ -447,7 +456,7 @@ int ie_modified(struct index_state *istate,
 	    (S_ISGITLINK(ce->ce_mode) || ce->ce_stat_data.sd_size != 0))
 		return changed;
 
-	changed_fs = ce_modified_check_fs(ce, st);
+	changed_fs = ce_modified_check_fs(istate, ce, st);
 	if (changed_fs)
 		return changed | changed_fs;
 	return 0;
@@ -542,7 +551,7 @@ static int index_name_stage_pos(const struct index_state *istate, const char *na
 	first = 0;
 	last = istate->cache_nr;
 	while (last > first) {
-		int next = (last + first) >> 1;
+		int next = first + ((last - first) >> 1);
 		struct cache_entry *ce = istate->cache[next];
 		int cmp = cache_name_stage_compare(name, namelen, stage, ce->name, ce_namelen(ce), ce_stage(ce));
 		if (!cmp)
@@ -582,13 +591,19 @@ int remove_index_entry_at(struct index_state *istate, int pos)
  * CE_REMOVE is set in ce_flags.  This is much more effective than
  * calling remove_index_entry_at() for each entry to be removed.
  */
-void remove_marked_cache_entries(struct index_state *istate)
+void remove_marked_cache_entries(struct index_state *istate, int invalidate)
 {
 	struct cache_entry **ce_array = istate->cache;
 	unsigned int i, j;
 
 	for (i = j = 0; i < istate->cache_nr; i++) {
 		if (ce_array[i]->ce_flags & CE_REMOVE) {
+			if (invalidate) {
+				cache_tree_invalidate_path(istate,
+							   ce_array[i]->name);
+				untracked_cache_remove_from_index(istate,
+								  ce_array[i]->name);
+			}
 			remove_name_hash(istate, ce_array[i]);
 			save_or_free_index_entry(istate, ce_array[i]);
 		}
@@ -664,7 +679,8 @@ static struct cache_entry *create_alias_ce(struct index_state *istate,
 	struct cache_entry *new_entry;
 
 	if (alias->ce_flags & CE_ADDED)
-		die("Will not add file alias '%s' ('%s' already exists in index)", ce->name, alias->name);
+		die(_("will not add file alias '%s' ('%s' already exists in index)"),
+		    ce->name, alias->name);
 
 	/* Ok, create the new entry using the name of the existing alias */
 	len = ce_namelen(alias);
@@ -679,7 +695,7 @@ void set_object_name_for_intent_to_add_entry(struct cache_entry *ce)
 {
 	struct object_id oid;
 	if (write_object_file("", 0, blob_type, &oid))
-		die("cannot create an empty blob in the object database");
+		die(_("cannot create an empty blob in the object database"));
 	oidcpy(&ce->oid, &oid);
 }
 
@@ -694,16 +710,19 @@ int add_to_index(struct index_state *istate, const char *path, struct stat *st,
 	int intent_only = flags & ADD_CACHE_INTENT;
 	int add_option = (ADD_CACHE_OK_TO_ADD|ADD_CACHE_OK_TO_REPLACE|
 			  (intent_only ? ADD_CACHE_NEW_ONLY : 0));
-	int newflags = HASH_WRITE_OBJECT;
+	int hash_flags = HASH_WRITE_OBJECT;
+	struct object_id oid;
 
-	if (flags & HASH_RENORMALIZE)
-		newflags |= HASH_RENORMALIZE;
+	if (flags & ADD_CACHE_RENORMALIZE)
+		hash_flags |= HASH_RENORMALIZE;
 
 	if (!S_ISREG(st_mode) && !S_ISLNK(st_mode) && !S_ISDIR(st_mode))
-		return error("%s: can only add regular files, symbolic links or git-directories", path);
+		return error(_("%s: can only add regular files, symbolic links or git-directories"), path);
 
 	namelen = strlen(path);
 	if (S_ISDIR(st_mode)) {
+		if (resolve_gitlink_ref(path, "HEAD", &oid) < 0)
+			return error(_("'%s' does not have a commit checked out"), path);
 		while (namelen && path[namelen-1] == '/')
 			namelen--;
 	}
@@ -711,7 +730,7 @@ int add_to_index(struct index_state *istate, const char *path, struct stat *st,
 	memcpy(ce->name, path, namelen);
 	ce->ce_namelen = namelen;
 	if (!intent_only)
-		fill_stat_cache_info(ce, st);
+		fill_stat_cache_info(istate, ce, st);
 	else
 		ce->ce_flags |= CE_INTENT_TO_ADD;
 
@@ -737,7 +756,7 @@ int add_to_index(struct index_state *istate, const char *path, struct stat *st,
 	if (ignore_case) {
 		adjust_dirname_case(istate, ce->name);
 	}
-	if (!(flags & HASH_RENORMALIZE)) {
+	if (!(flags & ADD_CACHE_RENORMALIZE)) {
 		alias = index_file_exists(istate, ce->name,
 					  ce_namelen(ce), ignore_case);
 		if (alias &&
@@ -753,9 +772,9 @@ int add_to_index(struct index_state *istate, const char *path, struct stat *st,
 		}
 	}
 	if (!intent_only) {
-		if (index_path(&ce->oid, path, st, newflags)) {
+		if (index_path(istate, &ce->oid, path, st, hash_flags)) {
 			discard_cache_entry(ce);
-			return error("unable to index file %s", path);
+			return error(_("unable to index file '%s'"), path);
 		}
 	} else
 		set_object_name_for_intent_to_add_entry(ce);
@@ -767,14 +786,14 @@ int add_to_index(struct index_state *istate, const char *path, struct stat *st,
 	/* It was suspected to be racily clean, but it turns out to be Ok */
 	was_same = (alias &&
 		    !ce_stage(alias) &&
-		    !oidcmp(&alias->oid, &ce->oid) &&
+		    oideq(&alias->oid, &ce->oid) &&
 		    ce->ce_mode == alias->ce_mode);
 
 	if (pretend)
 		discard_cache_entry(ce);
 	else if (add_index_entry(istate, ce, add_option)) {
 		discard_cache_entry(ce);
-		return error("unable to add %s to index", path);
+		return error(_("unable to add '%s' to index"), path);
 	}
 	if (verbose && !was_same)
 		printf("add '%s'\n", path);
@@ -785,7 +804,7 @@ int add_file_to_index(struct index_state *istate, const char *path, int flags)
 {
 	struct stat st;
 	if (lstat(path, &st))
-		die_errno("unable to stat '%s'", path);
+		die_errno(_("unable to stat '%s'"), path);
 	return add_to_index(istate, path, &st, flags);
 }
 
@@ -810,7 +829,7 @@ struct cache_entry *make_cache_entry(struct index_state *istate,
 	int len;
 
 	if (!verify_path(path, mode)) {
-		error("Invalid path '%s'", path);
+		error(_("invalid path '%s'"), path);
 		return NULL;
 	}
 
@@ -823,7 +842,7 @@ struct cache_entry *make_cache_entry(struct index_state *istate,
 	ce->ce_namelen = len;
 	ce->ce_mode = create_ce_mode(mode);
 
-	ret = refresh_cache_entry(&the_index, ce, refresh_options);
+	ret = refresh_cache_entry(istate, ce, refresh_options);
 	if (ret != ce)
 		discard_cache_entry(ce);
 	return ret;
@@ -836,7 +855,7 @@ struct cache_entry *make_transient_cache_entry(unsigned int mode, const struct o
 	int len;
 
 	if (!verify_path(path, mode)) {
-		error("Invalid path '%s'", path);
+		error(_("invalid path '%s'"), path);
 		return NULL;
 	}
 
@@ -942,11 +961,14 @@ static int verify_dotfile(const char *rest, unsigned mode)
 
 int verify_path(const char *path, unsigned mode)
 {
-	char c;
+	char c = 0;
 
 	if (has_dos_drive_prefix(path))
 		return 0;
 
+	if (!is_valid_path(path))
+		return 0;
+
 	goto inside;
 	for (;;) {
 		if (!c)
@@ -954,6 +976,7 @@ int verify_path(const char *path, unsigned mode)
 		if (is_dir_sep(c)) {
 inside:
 			if (protect_hfs) {
+
 				if (is_hfs_dotgit(path))
 					return 0;
 				if (S_ISLNK(mode)) {
@@ -962,6 +985,10 @@ inside:
 				}
 			}
 			if (protect_ntfs) {
+#ifdef GIT_WINDOWS_NATIVE
+				if (c == '\\')
+					return 0;
+#endif
 				if (is_ntfs_dotgit(path))
 					return 0;
 				if (S_ISLNK(mode)) {
@@ -974,7 +1001,15 @@ inside:
 			if ((c == '.' && !verify_dotfile(path, mode)) ||
 			    is_dir_sep(c) || c == '\0')
 				return 0;
+		} else if (c == '\\' && protect_ntfs) {
+			if (is_ntfs_dotgit(path))
+				return 0;
+			if (S_ISLNK(mode)) {
+				if (is_ntfs_dotgitmodules(path))
+					return 0;
+			}
 		}
+
 		c = *path++;
 	}
 }
@@ -1138,20 +1173,6 @@ static int has_dir_name(struct index_state *istate,
 				return retval;
 			}
 
-			if (istate->cache_nr > 0 &&
-				ce_namelen(istate->cache[istate->cache_nr - 1]) > len) {
-				/*
-				 * The directory prefix lines up with part of
-				 * a longer file or directory name, but sorts
-				 * after it, so this sub-directory cannot
-				 * collide with a file.
-				 *
-				 * last: xxx/yy-file (because '-' sorts before '/')
-				 * this: xxx/yy/abc
-				 */
-				return retval;
-			}
-
 			/*
 			 * This is a possible collision. Fall through and
 			 * let the regular search code handle it.
@@ -1259,7 +1280,7 @@ static int add_index_entry_with_check(struct index_state *istate, struct cache_e
 	 */
 	if (istate->cache_nr > 0 &&
 		strcmp(ce->name, istate->cache[istate->cache_nr - 1]->name) > 0)
-		pos = -istate->cache_nr - 1;
+		pos = index_pos_to_insert_pos(istate->cache_nr);
 	else
 		pos = index_name_stage_pos(istate, ce->name, ce_namelen(ce), ce_stage(ce));
 
@@ -1289,12 +1310,12 @@ static int add_index_entry_with_check(struct index_state *istate, struct cache_e
 	if (!ok_to_add)
 		return -1;
 	if (!verify_path(ce->name, ce->ce_mode))
-		return error("Invalid path '%s'", ce->name);
+		return error(_("invalid path '%s'"), ce->name);
 
 	if (!skip_df_check &&
 	    check_file_directory_conflict(istate, ce, pos, ok_to_replace)) {
 		if (!ok_to_replace)
-			return error("'%s' appears as both a file and as a directory",
+			return error(_("'%s' appears as both a file and as a directory"),
 				     ce->name);
 		pos = index_name_stage_pos(istate, ce->name, ce_namelen(ce), ce_stage(ce));
 		pos = -pos-1;
@@ -1415,7 +1436,7 @@ static struct cache_entry *refresh_cache_ent(struct index_state *istate,
 			 */
 			if (!S_ISGITLINK(ce->ce_mode)) {
 				ce_mark_uptodate(ce);
-				mark_fsmonitor_valid(ce);
+				mark_fsmonitor_valid(istate, ce);
 			}
 			return ce;
 		}
@@ -1430,7 +1451,7 @@ static struct cache_entry *refresh_cache_ent(struct index_state *istate,
 	updated = make_empty_cache_entry(istate, ce_namelen(ce));
 	copy_cache_entry(updated, ce);
 	memcpy(updated->name, ce->name, ce->ce_namelen + 1);
-	fill_stat_cache_info(updated, &st);
+	fill_stat_cache_info(istate, updated, &st);
 	/*
 	 * If ignore_valid is not set, we should leave CE_VALID bit
 	 * alone.  Otherwise, paths marked with --no-assume-unchanged
@@ -1455,6 +1476,27 @@ static void show_file(const char * fmt, const char * name, int in_porcelain,
 	printf(fmt, name);
 }
 
+int repo_refresh_and_write_index(struct repository *repo,
+				 unsigned int refresh_flags,
+				 unsigned int write_flags,
+				 int gentle,
+				 const struct pathspec *pathspec,
+				 char *seen, const char *header_msg)
+{
+	struct lock_file lock_file = LOCK_INIT;
+	int fd, ret = 0;
+
+	fd = repo_hold_locked_index(repo, &lock_file, 0);
+	if (!gentle && fd < 0)
+		return -1;
+	if (refresh_index(repo->index, refresh_flags, pathspec, seen, header_msg))
+		ret = 1;
+	if (0 <= fd && write_locked_index(repo->index, &lock_file, COMMIT_LOCK | write_flags))
+		ret = -1;
+	return ret;
+}
+
+
 int refresh_index(struct index_state *istate, unsigned int flags,
 		  const struct pathspec *pathspec,
 		  char *seen, const char *header_msg)
@@ -1476,13 +1518,24 @@ int refresh_index(struct index_state *istate, unsigned int flags,
 	const char *typechange_fmt;
 	const char *added_fmt;
 	const char *unmerged_fmt;
-	uint64_t start = getnanotime();
-
-	modified_fmt = (in_porcelain ? "M\t%s\n" : "%s: needs update\n");
-	deleted_fmt = (in_porcelain ? "D\t%s\n" : "%s: needs update\n");
-	typechange_fmt = (in_porcelain ? "T\t%s\n" : "%s needs update\n");
-	added_fmt = (in_porcelain ? "A\t%s\n" : "%s needs update\n");
-	unmerged_fmt = (in_porcelain ? "U\t%s\n" : "%s: needs merge\n");
+	struct progress *progress = NULL;
+
+	if (flags & REFRESH_PROGRESS && isatty(2))
+		progress = start_delayed_progress(_("Refresh index"),
+						  istate->cache_nr);
+
+	trace_performance_enter();
+	modified_fmt   = in_porcelain ? "M\t%s\n" : "%s: needs update\n";
+	deleted_fmt    = in_porcelain ? "D\t%s\n" : "%s: needs update\n";
+	typechange_fmt = in_porcelain ? "T\t%s\n" : "%s: needs update\n";
+	added_fmt      = in_porcelain ? "A\t%s\n" : "%s: needs update\n";
+	unmerged_fmt   = in_porcelain ? "U\t%s\n" : "%s: needs merge\n";
+	/*
+	 * Use the multi-threaded preload_index() to refresh most of the
+	 * cache entries quickly then in the single threaded loop below,
+	 * we only have to do the special cases that are left.
+	 */
+	preload_index(istate, pathspec, 0);
 	for (i = 0; i < istate->cache_nr; i++) {
 		struct cache_entry *ce, *new_entry;
 		int cache_errno = 0;
@@ -1493,7 +1546,7 @@ int refresh_index(struct index_state *istate, unsigned int flags,
 		if (ignore_submodules && S_ISGITLINK(ce->ce_mode))
 			continue;
 
-		if (pathspec && !ce_path_match(&the_index, ce, pathspec, seen))
+		if (pathspec && !ce_path_match(istate, ce, pathspec, seen))
 			filtered = 1;
 
 		if (ce_stage(ce)) {
@@ -1516,6 +1569,8 @@ int refresh_index(struct index_state *istate, unsigned int flags,
 		new_entry = refresh_cache_ent(istate, ce, options, &cache_errno, &changed);
 		if (new_entry == ce)
 			continue;
+		if (progress)
+			display_progress(progress, i);
 		if (!new_entry) {
 			const char *fmt;
 
@@ -1547,7 +1602,11 @@ int refresh_index(struct index_state *istate, unsigned int flags,
 
 		replace_index_entry(istate, i, new_entry);
 	}
-	trace_performance_since(start, "refresh index");
+	if (progress) {
+		display_progress(progress, istate->cache_nr);
+		stop_progress(&progress);
+	}
+	trace_performance_leave("refresh index");
 	return has_errors;
 }
 
@@ -1565,16 +1624,17 @@ struct cache_entry *refresh_cache_entry(struct index_state *istate,
 
 #define INDEX_FORMAT_DEFAULT 3
 
-static unsigned int get_index_format_default(void)
+static unsigned int get_index_format_default(struct repository *r)
 {
 	char *envversion = getenv("GIT_INDEX_VERSION");
 	char *endp;
-	int value;
 	unsigned int version = INDEX_FORMAT_DEFAULT;
 
 	if (!envversion) {
-		if (!git_config_get_int("index.version", &value))
-			version = value;
+		prepare_repo_settings(r);
+
+		if (r->settings.index_version >= 0)
+			version = r->settings.index_version;
 		if (version < INDEX_FORMAT_LB || INDEX_FORMAT_UB < version) {
 			warning(_("index.version set, but the value is invalid.\n"
 				  "Using version %i"), INDEX_FORMAT_DEFAULT);
@@ -1610,39 +1670,24 @@ struct ondisk_cache_entry {
 	uint32_t uid;
 	uint32_t gid;
 	uint32_t size;
-	unsigned char sha1[20];
-	uint16_t flags;
-	char name[FLEX_ARRAY]; /* more */
-};
-
-/*
- * This struct is used when CE_EXTENDED bit is 1
- * The struct must match ondisk_cache_entry exactly from
- * ctime till flags
- */
-struct ondisk_cache_entry_extended {
-	struct cache_time ctime;
-	struct cache_time mtime;
-	uint32_t dev;
-	uint32_t ino;
-	uint32_t mode;
-	uint32_t uid;
-	uint32_t gid;
-	uint32_t size;
-	unsigned char sha1[20];
-	uint16_t flags;
-	uint16_t flags2;
-	char name[FLEX_ARRAY]; /* more */
+	/*
+	 * unsigned char hash[hashsz];
+	 * uint16_t flags;
+	 * if (flags & CE_EXTENDED)
+	 *	uint16_t flags2;
+	 */
+	unsigned char data[GIT_MAX_RAWSZ + 2 * sizeof(uint16_t)];
+	char name[FLEX_ARRAY];
 };
 
 /* These are only used for v3 or lower */
 #define align_padding_size(size, len) ((size + (len) + 8) & ~7) - (size + len)
-#define align_flex_name(STRUCT,len) ((offsetof(struct STRUCT,name) + (len) + 8) & ~7)
+#define align_flex_name(STRUCT,len) ((offsetof(struct STRUCT,data) + (len) + 8) & ~7)
 #define ondisk_cache_entry_size(len) align_flex_name(ondisk_cache_entry,len)
-#define ondisk_cache_entry_extended_size(len) align_flex_name(ondisk_cache_entry_extended,len)
-#define ondisk_ce_size(ce) (((ce)->ce_flags & CE_EXTENDED) ? \
-			    ondisk_cache_entry_extended_size(ce_namelen(ce)) : \
-			    ondisk_cache_entry_size(ce_namelen(ce)))
+#define ondisk_data_size(flags, len) (the_hash_algo->rawsz + \
+				     ((flags & CE_EXTENDED) ? 2 : 1) * sizeof(uint16_t) + len)
+#define ondisk_data_size_max(len) (ondisk_data_size(CE_EXTENDED, len))
+#define ondisk_ce_size(ce) (ondisk_cache_entry_size(ondisk_data_size((ce)->ce_flags, ce_namelen(ce))))
 
 /* Allow fsck to force verification of the index checksum. */
 int verify_index_checksum;
@@ -1650,17 +1695,17 @@ int verify_index_checksum;
 /* Allow fsck to force verification of the cache entry order. */
 int verify_ce_order;
 
-static int verify_hdr(struct cache_header *hdr, unsigned long size)
+static int verify_hdr(const struct cache_header *hdr, unsigned long size)
 {
 	git_hash_ctx c;
 	unsigned char hash[GIT_MAX_RAWSZ];
 	int hdr_version;
 
 	if (hdr->hdr_signature != htonl(CACHE_SIGNATURE))
-		return error("bad signature");
+		return error(_("bad signature 0x%08x"), hdr->hdr_signature);
 	hdr_version = ntohl(hdr->hdr_version);
 	if (hdr_version < INDEX_FORMAT_LB || INDEX_FORMAT_UB < hdr_version)
-		return error("bad index version %d", hdr_version);
+		return error(_("bad index version %d"), hdr_version);
 
 	if (!verify_index_checksum)
 		return 0;
@@ -1668,13 +1713,13 @@ static int verify_hdr(struct cache_header *hdr, unsigned long size)
 	the_hash_algo->init_fn(&c);
 	the_hash_algo->update_fn(&c, hdr, size - the_hash_algo->rawsz);
 	the_hash_algo->final_fn(hash, &c);
-	if (hashcmp(hash, (unsigned char *)hdr + size - the_hash_algo->rawsz))
-		return error("bad index file sha1 signature");
+	if (!hasheq(hash, (unsigned char *)hdr + size - the_hash_algo->rawsz))
+		return error(_("bad index file sha1 signature"));
 	return 0;
 }
 
 static int read_index_extension(struct index_state *istate,
-				const char *ext, void *data, unsigned long sz)
+				const char *ext, const char *data, unsigned long sz)
 {
 	switch (CACHE_EXT(ext)) {
 	case CACHE_EXT_TREE:
@@ -1693,117 +1738,107 @@ static int read_index_extension(struct index_state *istate,
 	case CACHE_EXT_FSMONITOR:
 		read_fsmonitor_extension(istate, data, sz);
 		break;
+	case CACHE_EXT_ENDOFINDEXENTRIES:
+	case CACHE_EXT_INDEXENTRYOFFSETTABLE:
+		/* already handled in do_read_index() */
+		break;
 	default:
 		if (*ext < 'A' || 'Z' < *ext)
-			return error("index uses %.4s extension, which we do not understand",
+			return error(_("index uses %.4s extension, which we do not understand"),
 				     ext);
-		fprintf(stderr, "ignoring %.4s extension\n", ext);
+		fprintf_ln(stderr, _("ignoring %.4s extension"), ext);
 		break;
 	}
 	return 0;
 }
 
-int hold_locked_index(struct lock_file *lk, int lock_flags)
-{
-	return hold_lock_file_for_update(lk, get_index_file(), lock_flags);
-}
-
-int read_index(struct index_state *istate)
-{
-	return read_index_from(istate, get_index_file(), get_git_dir());
-}
-
-static struct cache_entry *cache_entry_from_ondisk(struct mem_pool *mem_pool,
-						   struct ondisk_cache_entry *ondisk,
-						   unsigned int flags,
-						   const char *name,
-						   size_t len)
-{
-	struct cache_entry *ce = mem_pool__ce_alloc(mem_pool, len);
-
-	ce->ce_stat_data.sd_ctime.sec = get_be32(&ondisk->ctime.sec);
-	ce->ce_stat_data.sd_mtime.sec = get_be32(&ondisk->mtime.sec);
-	ce->ce_stat_data.sd_ctime.nsec = get_be32(&ondisk->ctime.nsec);
-	ce->ce_stat_data.sd_mtime.nsec = get_be32(&ondisk->mtime.nsec);
-	ce->ce_stat_data.sd_dev   = get_be32(&ondisk->dev);
-	ce->ce_stat_data.sd_ino   = get_be32(&ondisk->ino);
-	ce->ce_mode  = get_be32(&ondisk->mode);
-	ce->ce_stat_data.sd_uid   = get_be32(&ondisk->uid);
-	ce->ce_stat_data.sd_gid   = get_be32(&ondisk->gid);
-	ce->ce_stat_data.sd_size  = get_be32(&ondisk->size);
-	ce->ce_flags = flags & ~CE_NAMEMASK;
-	ce->ce_namelen = len;
-	ce->index = 0;
-	hashcpy(ce->oid.hash, ondisk->sha1);
-	memcpy(ce->name, name, len);
-	ce->name[len] = '\0';
-	return ce;
-}
-
-/*
- * Adjacent cache entries tend to share the leading paths, so it makes
- * sense to only store the differences in later entries.  In the v4
- * on-disk format of the index, each on-disk cache entry stores the
- * number of bytes to be stripped from the end of the previous name,
- * and the bytes to append to the result, to come up with its name.
- */
-static unsigned long expand_name_field(struct strbuf *name, const char *cp_)
-{
-	const unsigned char *ep, *cp = (const unsigned char *)cp_;
-	size_t len = decode_varint(&cp);
-
-	if (name->len < len)
-		die("malformed name field in the index");
-	strbuf_remove(name, name->len - len, len);
-	for (ep = cp; *ep; ep++)
-		; /* find the end */
-	strbuf_add(name, cp, ep - cp);
-	return (const char *)ep + 1 - cp_;
-}
-
-static struct cache_entry *create_from_disk(struct mem_pool *mem_pool,
+static struct cache_entry *create_from_disk(struct mem_pool *ce_mem_pool,
+					    unsigned int version,
 					    struct ondisk_cache_entry *ondisk,
 					    unsigned long *ent_size,
-					    struct strbuf *previous_name)
+					    const struct cache_entry *previous_ce)
 {
 	struct cache_entry *ce;
 	size_t len;
 	const char *name;
+	const unsigned hashsz = the_hash_algo->rawsz;
+	const uint16_t *flagsp = (const uint16_t *)(ondisk->data + hashsz);
 	unsigned int flags;
+	size_t copy_len = 0;
+	/*
+	 * Adjacent cache entries tend to share the leading paths, so it makes
+	 * sense to only store the differences in later entries.  In the v4
+	 * on-disk format of the index, each on-disk cache entry stores the
+	 * number of bytes to be stripped from the end of the previous name,
+	 * and the bytes to append to the result, to come up with its name.
+	 */
+	int expand_name_field = version == 4;
 
 	/* On-disk flags are just 16 bits */
-	flags = get_be16(&ondisk->flags);
+	flags = get_be16(flagsp);
 	len = flags & CE_NAMEMASK;
 
 	if (flags & CE_EXTENDED) {
-		struct ondisk_cache_entry_extended *ondisk2;
 		int extended_flags;
-		ondisk2 = (struct ondisk_cache_entry_extended *)ondisk;
-		extended_flags = get_be16(&ondisk2->flags2) << 16;
+		extended_flags = get_be16(flagsp + 1) << 16;
 		/* We do not yet understand any bit out of CE_EXTENDED_FLAGS */
 		if (extended_flags & ~CE_EXTENDED_FLAGS)
-			die("Unknown index entry format %08x", extended_flags);
+			die(_("unknown index entry format 0x%08x"), extended_flags);
 		flags |= extended_flags;
-		name = ondisk2->name;
+		name = (const char *)(flagsp + 2);
 	}
 	else
-		name = ondisk->name;
+		name = (const char *)(flagsp + 1);
+
+	if (expand_name_field) {
+		const unsigned char *cp = (const unsigned char *)name;
+		size_t strip_len, previous_len;
+
+		/* If we're at the beginning of a block, ignore the previous name */
+		strip_len = decode_varint(&cp);
+		if (previous_ce) {
+			previous_len = previous_ce->ce_namelen;
+			if (previous_len < strip_len)
+				die(_("malformed name field in the index, near path '%s'"),
+					previous_ce->name);
+			copy_len = previous_len - strip_len;
+		}
+		name = (const char *)cp;
+	}
 
-	if (!previous_name) {
-		/* v3 and earlier */
-		if (len == CE_NAMEMASK)
-			len = strlen(name);
-		ce = cache_entry_from_ondisk(mem_pool, ondisk, flags, name, len);
+	if (len == CE_NAMEMASK) {
+		len = strlen(name);
+		if (expand_name_field)
+			len += copy_len;
+	}
 
-		*ent_size = ondisk_ce_size(ce);
-	} else {
-		unsigned long consumed;
-		consumed = expand_name_field(previous_name, name);
-		ce = cache_entry_from_ondisk(mem_pool, ondisk, flags,
-					     previous_name->buf,
-					     previous_name->len);
+	ce = mem_pool__ce_alloc(ce_mem_pool, len);
 
-		*ent_size = (name - ((char *)ondisk)) + consumed;
+	ce->ce_stat_data.sd_ctime.sec = get_be32(&ondisk->ctime.sec);
+	ce->ce_stat_data.sd_mtime.sec = get_be32(&ondisk->mtime.sec);
+	ce->ce_stat_data.sd_ctime.nsec = get_be32(&ondisk->ctime.nsec);
+	ce->ce_stat_data.sd_mtime.nsec = get_be32(&ondisk->mtime.nsec);
+	ce->ce_stat_data.sd_dev   = get_be32(&ondisk->dev);
+	ce->ce_stat_data.sd_ino   = get_be32(&ondisk->ino);
+	ce->ce_mode  = get_be32(&ondisk->mode);
+	ce->ce_stat_data.sd_uid   = get_be32(&ondisk->uid);
+	ce->ce_stat_data.sd_gid   = get_be32(&ondisk->gid);
+	ce->ce_stat_data.sd_size  = get_be32(&ondisk->size);
+	ce->ce_flags = flags & ~CE_NAMEMASK;
+	ce->ce_namelen = len;
+	ce->index = 0;
+	hashcpy(ce->oid.hash, ondisk->data);
+	memcpy(ce->name, name, len);
+	ce->name[len] = '\0';
+
+	if (expand_name_field) {
+		if (copy_len)
+			memcpy(ce->name, previous_ce->name, copy_len);
+		memcpy(ce->name + copy_len, name, len + 1 - copy_len);
+		*ent_size = (name - ((char *)ondisk)) + len + 1 - copy_len;
+	} else {
+		memcpy(ce->name, name, len + 1);
+		*ent_size = ondisk_ce_size(ce);
 	}
 	return ce;
 }
@@ -1821,13 +1856,13 @@ static void check_ce_order(struct index_state *istate)
 		int name_compare = strcmp(ce->name, next_ce->name);
 
 		if (0 < name_compare)
-			die("unordered stage entries in index");
+			die(_("unordered stage entries in index"));
 		if (!name_compare) {
 			if (!ce_stage(ce))
-				die("multiple stage entries for merged file '%s'",
+				die(_("multiple stage entries for merged file '%s'"),
 				    ce->name);
 			if (ce_stage(ce) > ce_stage(next_ce))
-				die("unordered stage entries for '%s'",
+				die(_("unordered stage entries for '%s'"),
 				    ce->name);
 		}
 	}
@@ -1835,18 +1870,17 @@ static void check_ce_order(struct index_state *istate)
 
 static void tweak_untracked_cache(struct index_state *istate)
 {
-	switch (git_config_get_untracked_cache()) {
-	case -1: /* keep: do nothing */
-		break;
-	case 0: /* false */
+	struct repository *r = the_repository;
+
+	prepare_repo_settings(r);
+
+	if (r->settings.core_untracked_cache  == UNTRACKED_CACHE_REMOVE) {
 		remove_untracked_cache(istate);
-		break;
-	case 1: /* true */
-		add_untracked_cache(istate);
-		break;
-	default: /* unknown value: do nothing */
-		break;
+		return;
 	}
+
+	if (r->settings.core_untracked_cache == UNTRACKED_CACHE_WRITE)
+		add_untracked_cache(istate);
 }
 
 static void tweak_split_index(struct index_state *istate)
@@ -1885,20 +1919,235 @@ static size_t estimate_cache_size(size_t ondisk_size, unsigned int entries)
 	/*
 	 * Account for potential alignment differences.
 	 */
-	per_entry += align_padding_size(sizeof(struct cache_entry), -sizeof(struct ondisk_cache_entry));
+	per_entry += align_padding_size(per_entry, 0);
 	return ondisk_size + entries * per_entry;
 }
 
+struct index_entry_offset
+{
+	/* starting byte offset into index file, count of index entries in this block */
+	int offset, nr;
+};
+
+struct index_entry_offset_table
+{
+	int nr;
+	struct index_entry_offset entries[FLEX_ARRAY];
+};
+
+static struct index_entry_offset_table *read_ieot_extension(const char *mmap, size_t mmap_size, size_t offset);
+static void write_ieot_extension(struct strbuf *sb, struct index_entry_offset_table *ieot);
+
+static size_t read_eoie_extension(const char *mmap, size_t mmap_size);
+static void write_eoie_extension(struct strbuf *sb, git_hash_ctx *eoie_context, size_t offset);
+
+struct load_index_extensions
+{
+	pthread_t pthread;
+	struct index_state *istate;
+	const char *mmap;
+	size_t mmap_size;
+	unsigned long src_offset;
+};
+
+static void *load_index_extensions(void *_data)
+{
+	struct load_index_extensions *p = _data;
+	unsigned long src_offset = p->src_offset;
+
+	while (src_offset <= p->mmap_size - the_hash_algo->rawsz - 8) {
+		/* After an array of active_nr index entries,
+		 * there can be arbitrary number of extended
+		 * sections, each of which is prefixed with
+		 * extension name (4-byte) and section length
+		 * in 4-byte network byte order.
+		 */
+		uint32_t extsize = get_be32(p->mmap + src_offset + 4);
+		if (read_index_extension(p->istate,
+					 p->mmap + src_offset,
+					 p->mmap + src_offset + 8,
+					 extsize) < 0) {
+			munmap((void *)p->mmap, p->mmap_size);
+			die(_("index file corrupt"));
+		}
+		src_offset += 8;
+		src_offset += extsize;
+	}
+
+	return NULL;
+}
+
+/*
+ * A helper function that will load the specified range of cache entries
+ * from the memory mapped file and add them to the given index.
+ */
+static unsigned long load_cache_entry_block(struct index_state *istate,
+			struct mem_pool *ce_mem_pool, int offset, int nr, const char *mmap,
+			unsigned long start_offset, const struct cache_entry *previous_ce)
+{
+	int i;
+	unsigned long src_offset = start_offset;
+
+	for (i = offset; i < offset + nr; i++) {
+		struct ondisk_cache_entry *disk_ce;
+		struct cache_entry *ce;
+		unsigned long consumed;
+
+		disk_ce = (struct ondisk_cache_entry *)(mmap + src_offset);
+		ce = create_from_disk(ce_mem_pool, istate->version, disk_ce, &consumed, previous_ce);
+		set_index_entry(istate, i, ce);
+
+		src_offset += consumed;
+		previous_ce = ce;
+	}
+	return src_offset - start_offset;
+}
+
+static unsigned long load_all_cache_entries(struct index_state *istate,
+			const char *mmap, size_t mmap_size, unsigned long src_offset)
+{
+	unsigned long consumed;
+
+	istate->ce_mem_pool = xmalloc(sizeof(*istate->ce_mem_pool));
+	if (istate->version == 4) {
+		mem_pool_init(istate->ce_mem_pool,
+				estimate_cache_size_from_compressed(istate->cache_nr));
+	} else {
+		mem_pool_init(istate->ce_mem_pool,
+				estimate_cache_size(mmap_size, istate->cache_nr));
+	}
+
+	consumed = load_cache_entry_block(istate, istate->ce_mem_pool,
+					0, istate->cache_nr, mmap, src_offset, NULL);
+	return consumed;
+}
+
+/*
+ * Mostly randomly chosen maximum thread counts: we
+ * cap the parallelism to online_cpus() threads, and we want
+ * to have at least 10000 cache entries per thread for it to
+ * be worth starting a thread.
+ */
+
+#define THREAD_COST		(10000)
+
+struct load_cache_entries_thread_data
+{
+	pthread_t pthread;
+	struct index_state *istate;
+	struct mem_pool *ce_mem_pool;
+	int offset;
+	const char *mmap;
+	struct index_entry_offset_table *ieot;
+	int ieot_start;		/* starting index into the ieot array */
+	int ieot_blocks;	/* count of ieot entries to process */
+	unsigned long consumed;	/* return # of bytes in index file processed */
+};
+
+/*
+ * A thread proc to run the load_cache_entries() computation
+ * across multiple background threads.
+ */
+static void *load_cache_entries_thread(void *_data)
+{
+	struct load_cache_entries_thread_data *p = _data;
+	int i;
+
+	/* iterate across all ieot blocks assigned to this thread */
+	for (i = p->ieot_start; i < p->ieot_start + p->ieot_blocks; i++) {
+		p->consumed += load_cache_entry_block(p->istate, p->ce_mem_pool,
+			p->offset, p->ieot->entries[i].nr, p->mmap, p->ieot->entries[i].offset, NULL);
+		p->offset += p->ieot->entries[i].nr;
+	}
+	return NULL;
+}
+
+static unsigned long load_cache_entries_threaded(struct index_state *istate, const char *mmap, size_t mmap_size,
+						 int nr_threads, struct index_entry_offset_table *ieot)
+{
+	int i, offset, ieot_blocks, ieot_start, err;
+	struct load_cache_entries_thread_data *data;
+	unsigned long consumed = 0;
+
+	/* a little sanity checking */
+	if (istate->name_hash_initialized)
+		BUG("the name hash isn't thread safe");
+
+	istate->ce_mem_pool = xmalloc(sizeof(*istate->ce_mem_pool));
+	mem_pool_init(istate->ce_mem_pool, 0);
+
+	/* ensure we have no more threads than we have blocks to process */
+	if (nr_threads > ieot->nr)
+		nr_threads = ieot->nr;
+	data = xcalloc(nr_threads, sizeof(*data));
+
+	offset = ieot_start = 0;
+	ieot_blocks = DIV_ROUND_UP(ieot->nr, nr_threads);
+	for (i = 0; i < nr_threads; i++) {
+		struct load_cache_entries_thread_data *p = &data[i];
+		int nr, j;
+
+		if (ieot_start + ieot_blocks > ieot->nr)
+			ieot_blocks = ieot->nr - ieot_start;
+
+		p->istate = istate;
+		p->offset = offset;
+		p->mmap = mmap;
+		p->ieot = ieot;
+		p->ieot_start = ieot_start;
+		p->ieot_blocks = ieot_blocks;
+
+		/* create a mem_pool for each thread */
+		nr = 0;
+		for (j = p->ieot_start; j < p->ieot_start + p->ieot_blocks; j++)
+			nr += p->ieot->entries[j].nr;
+		p->ce_mem_pool = xmalloc(sizeof(*istate->ce_mem_pool));
+		if (istate->version == 4) {
+			mem_pool_init(p->ce_mem_pool,
+				estimate_cache_size_from_compressed(nr));
+		} else {
+			mem_pool_init(p->ce_mem_pool,
+				estimate_cache_size(mmap_size, nr));
+		}
+
+		err = pthread_create(&p->pthread, NULL, load_cache_entries_thread, p);
+		if (err)
+			die(_("unable to create load_cache_entries thread: %s"), strerror(err));
+
+		/* increment by the number of cache entries in the ieot block being processed */
+		for (j = 0; j < ieot_blocks; j++)
+			offset += ieot->entries[ieot_start + j].nr;
+		ieot_start += ieot_blocks;
+	}
+
+	for (i = 0; i < nr_threads; i++) {
+		struct load_cache_entries_thread_data *p = &data[i];
+
+		err = pthread_join(p->pthread, NULL);
+		if (err)
+			die(_("unable to join load_cache_entries thread: %s"), strerror(err));
+		mem_pool_combine(istate->ce_mem_pool, p->ce_mem_pool);
+		consumed += p->consumed;
+	}
+
+	free(data);
+
+	return consumed;
+}
+
 /* remember to discard_cache() before reading a different cache! */
 int do_read_index(struct index_state *istate, const char *path, int must_exist)
 {
-	int fd, i;
+	int fd;
 	struct stat st;
 	unsigned long src_offset;
-	struct cache_header *hdr;
-	void *mmap;
+	const struct cache_header *hdr;
+	const char *mmap;
 	size_t mmap_size;
-	struct strbuf previous_name_buf = STRBUF_INIT, *previous_name;
+	struct load_index_extensions p;
+	size_t extension_offset = 0;
+	int nr_threads, cpus;
+	struct index_entry_offset_table *ieot = NULL;
 
 	if (istate->initialized)
 		return istate->cache_nr;
@@ -1909,22 +2158,22 @@ int do_read_index(struct index_state *istate, const char *path, int must_exist)
 	if (fd < 0) {
 		if (!must_exist && errno == ENOENT)
 			return 0;
-		die_errno("%s: index file open failed", path);
+		die_errno(_("%s: index file open failed"), path);
 	}
 
 	if (fstat(fd, &st))
-		die_errno("cannot stat the open index");
+		die_errno(_("%s: cannot stat the open index"), path);
 
 	mmap_size = xsize_t(st.st_size);
 	if (mmap_size < sizeof(struct cache_header) + the_hash_algo->rawsz)
-		die("index file smaller than expected");
+		die(_("%s: index file smaller than expected"), path);
 
-	mmap = xmmap(NULL, mmap_size, PROT_READ, MAP_PRIVATE, fd, 0);
+	mmap = xmmap_gently(NULL, mmap_size, PROT_READ, MAP_PRIVATE, fd, 0);
 	if (mmap == MAP_FAILED)
-		die_errno("unable to map index file");
+		die_errno(_("%s: unable to map index file"), path);
 	close(fd);
 
-	hdr = mmap;
+	hdr = (const struct cache_header *)mmap;
 	if (verify_hdr(hdr, mmap_size) < 0)
 		goto unmap;
 
@@ -1935,56 +2184,82 @@ int do_read_index(struct index_state *istate, const char *path, int must_exist)
 	istate->cache = xcalloc(istate->cache_alloc, sizeof(*istate->cache));
 	istate->initialized = 1;
 
-	if (istate->version == 4) {
-		previous_name = &previous_name_buf;
-		mem_pool_init(&istate->ce_mem_pool,
-			      estimate_cache_size_from_compressed(istate->cache_nr));
-	} else {
-		previous_name = NULL;
-		mem_pool_init(&istate->ce_mem_pool,
-			      estimate_cache_size(mmap_size, istate->cache_nr));
-	}
+	p.istate = istate;
+	p.mmap = mmap;
+	p.mmap_size = mmap_size;
 
 	src_offset = sizeof(*hdr);
-	for (i = 0; i < istate->cache_nr; i++) {
-		struct ondisk_cache_entry *disk_ce;
-		struct cache_entry *ce;
-		unsigned long consumed;
 
-		disk_ce = (struct ondisk_cache_entry *)((char *)mmap + src_offset);
-		ce = create_from_disk(istate->ce_mem_pool, disk_ce, &consumed, previous_name);
-		set_index_entry(istate, i, ce);
+	if (git_config_get_index_threads(&nr_threads))
+		nr_threads = 1;
 
-		src_offset += consumed;
+	/* TODO: does creating more threads than cores help? */
+	if (!nr_threads) {
+		nr_threads = istate->cache_nr / THREAD_COST;
+		cpus = online_cpus();
+		if (nr_threads > cpus)
+			nr_threads = cpus;
 	}
-	strbuf_release(&previous_name_buf);
+
+	if (!HAVE_THREADS)
+		nr_threads = 1;
+
+	if (nr_threads > 1) {
+		extension_offset = read_eoie_extension(mmap, mmap_size);
+		if (extension_offset) {
+			int err;
+
+			p.src_offset = extension_offset;
+			err = pthread_create(&p.pthread, NULL, load_index_extensions, &p);
+			if (err)
+				die(_("unable to create load_index_extensions thread: %s"), strerror(err));
+
+			nr_threads--;
+		}
+	}
+
+	/*
+	 * Locate and read the index entry offset table so that we can use it
+	 * to multi-thread the reading of the cache entries.
+	 */
+	if (extension_offset && nr_threads > 1)
+		ieot = read_ieot_extension(mmap, mmap_size, extension_offset);
+
+	if (ieot) {
+		src_offset += load_cache_entries_threaded(istate, mmap, mmap_size, nr_threads, ieot);
+		free(ieot);
+	} else {
+		src_offset += load_all_cache_entries(istate, mmap, mmap_size, src_offset);
+	}
+
 	istate->timestamp.sec = st.st_mtime;
 	istate->timestamp.nsec = ST_MTIME_NSEC(st);
 
-	while (src_offset <= mmap_size - the_hash_algo->rawsz - 8) {
-		/* After an array of active_nr index entries,
-		 * there can be arbitrary number of extended
-		 * sections, each of which is prefixed with
-		 * extension name (4-byte) and section length
-		 * in 4-byte network byte order.
-		 */
-		uint32_t extsize;
-		memcpy(&extsize, (char *)mmap + src_offset + 4, 4);
-		extsize = ntohl(extsize);
-		if (read_index_extension(istate,
-					 (const char *) mmap + src_offset,
-					 (char *) mmap + src_offset + 8,
-					 extsize) < 0)
-			goto unmap;
-		src_offset += 8;
-		src_offset += extsize;
+	/* if we created a thread, join it otherwise load the extensions on the primary thread */
+	if (extension_offset) {
+		int ret = pthread_join(p.pthread, NULL);
+		if (ret)
+			die(_("unable to join load_index_extensions thread: %s"), strerror(ret));
+	} else {
+		p.src_offset = src_offset;
+		load_index_extensions(&p);
 	}
-	munmap(mmap, mmap_size);
+	munmap((void *)mmap, mmap_size);
+
+	/*
+	 * TODO trace2: replace "the_repository" with the actual repo instance
+	 * that is associated with the given "istate".
+	 */
+	trace2_data_intmax("index", the_repository, "read/version",
+			   istate->version);
+	trace2_data_intmax("index", the_repository, "read/cache_nr",
+			   istate->cache_nr);
+
 	return istate->cache_nr;
 
 unmap:
-	munmap(mmap, mmap_size);
-	die("index file corrupt");
+	munmap((void *)mmap, mmap_size);
+	die(_("index file corrupt"));
 }
 
 /*
@@ -1996,13 +2271,12 @@ unmap:
 static void freshen_shared_index(const char *shared_index, int warn)
 {
 	if (!check_and_freshen_file(shared_index, 1) && warn)
-		warning("could not freshen shared index '%s'", shared_index);
+		warning(_("could not freshen shared index '%s'"), shared_index);
 }
 
 int read_index_from(struct index_state *istate, const char *path,
 		    const char *gitdir)
 {
-	uint64_t start = getnanotime();
 	struct split_index *split_index;
 	int ret;
 	char *base_oid_hex;
@@ -2012,8 +2286,17 @@ int read_index_from(struct index_state *istate, const char *path,
 	if (istate->initialized)
 		return istate->cache_nr;
 
+	/*
+	 * TODO trace2: replace "the_repository" with the actual repo instance
+	 * that is associated with the given "istate".
+	 */
+	trace2_region_enter_printf("index", "do_read_index", the_repository,
+				   "%s", path);
+	trace_performance_enter();
 	ret = do_read_index(istate, path, 0);
-	trace_performance_since(start, "read cache %s", path);
+	trace_performance_leave("read cache %s", path);
+	trace2_region_leave_printf("index", "do_read_index", the_repository,
+				   "%s", path);
 
 	split_index = istate->split_index;
 	if (!split_index || is_null_oid(&split_index->base_oid)) {
@@ -2021,6 +2304,7 @@ int read_index_from(struct index_state *istate, const char *path,
 		return ret;
 	}
 
+	trace_performance_enter();
 	if (split_index->base)
 		discard_index(split_index->base);
 	else
@@ -2028,16 +2312,20 @@ int read_index_from(struct index_state *istate, const char *path,
 
 	base_oid_hex = oid_to_hex(&split_index->base_oid);
 	base_path = xstrfmt("%s/sharedindex.%s", gitdir, base_oid_hex);
+	trace2_region_enter_printf("index", "shared/do_read_index",
+				   the_repository, "%s", base_path);
 	ret = do_read_index(split_index->base, base_path, 1);
-	if (oidcmp(&split_index->base_oid, &split_index->base->oid))
-		die("broken index, expect %s in %s, got %s",
+	trace2_region_leave_printf("index", "shared/do_read_index",
+				   the_repository, "%s", base_path);
+	if (!oideq(&split_index->base_oid, &split_index->base->oid))
+		die(_("broken index, expect %s in %s, got %s"),
 		    base_oid_hex, base_path,
 		    oid_to_hex(&split_index->base->oid));
 
 	freshen_shared_index(base_path, 0);
 	merge_base_index(istate);
 	post_read_index_from(istate);
-	trace_performance_since(start, "read cache %s", base_path);
+	trace_performance_leave("read cache %s", base_path);
 	free(base_path);
 	return ret;
 }
@@ -2066,6 +2354,7 @@ int discard_index(struct index_state *istate)
 	free_name_hash(istate);
 	cache_tree_free(&(istate->cache_tree));
 	istate->initialized = 0;
+	istate->fsmonitor_has_run_once = 0;
 	FREE_AND_NULL(istate->cache);
 	istate->cache_alloc = 0;
 	discard_split_index(istate);
@@ -2074,7 +2363,7 @@ int discard_index(struct index_state *istate)
 
 	if (istate->ce_mem_pool) {
 		mem_pool_discard(istate->ce_mem_pool, should_validate_cache_entries());
-		istate->ce_mem_pool = NULL;
+		FREE_AND_NULL(istate->ce_mem_pool);
 	}
 
 	return 0;
@@ -2096,14 +2385,14 @@ void validate_cache_entries(const struct index_state *istate)
 
 	for (i = 0; i < istate->cache_nr; i++) {
 		if (!istate) {
-			die("internal error: cache entry is not allocated from expected memory pool");
+			BUG("cache entry is not allocated from expected memory pool");
 		} else if (!istate->ce_mem_pool ||
 			!mem_pool_contains(istate->ce_mem_pool, istate->cache[i])) {
 			if (!istate->split_index ||
 				!istate->split_index->base ||
 				!istate->split_index->base->ce_mem_pool ||
 				!mem_pool_contains(istate->split_index->base->ce_mem_pool, istate->cache[i])) {
-				die("internal error: cache entry is not allocated from expected memory pool");
+				BUG("cache entry is not allocated from expected memory pool");
 			}
 		}
 	}
@@ -2122,22 +2411,20 @@ int unmerged_index(const struct index_state *istate)
 	return 0;
 }
 
-int index_has_changes(const struct index_state *istate,
-		      struct tree *tree,
-		      struct strbuf *sb)
+int repo_index_has_changes(struct repository *repo,
+			   struct tree *tree,
+			   struct strbuf *sb)
 {
+	struct index_state *istate = repo->index;
 	struct object_id cmp;
 	int i;
 
-	if (istate != &the_index) {
-		BUG("index_has_changes cannot yet accept istate != &the_index; do_diff_cache needs updating first.");
-	}
 	if (tree)
 		cmp = tree->object.oid;
 	if (tree || !get_oid_tree("HEAD", &cmp)) {
 		struct diff_options opt;
 
-		diff_setup(&opt);
+		repo_diff_setup(repo, &opt);
 		opt.flags.exit_with_status = 1;
 		if (!sb)
 			opt.flags.quick = 1;
@@ -2198,11 +2485,15 @@ static int ce_write(git_hash_ctx *context, int fd, void *data, unsigned int len)
 	return 0;
 }
 
-static int write_index_ext_header(git_hash_ctx *context, int fd,
-				  unsigned int ext, unsigned int sz)
+static int write_index_ext_header(git_hash_ctx *context, git_hash_ctx *eoie_context,
+				  int fd, unsigned int ext, unsigned int sz)
 {
 	ext = htonl(ext);
 	sz = htonl(sz);
+	if (eoie_context) {
+		the_hash_algo->update_fn(eoie_context, &ext, 4);
+		the_hash_algo->update_fn(eoie_context, &sz, 4);
+	}
 	return ((ce_write(context, fd, &ext, 4) < 0) ||
 		(ce_write(context, fd, &sz, 4) < 0)) ? -1 : 0;
 }
@@ -2230,7 +2521,8 @@ static int ce_flush(git_hash_ctx *context, int fd, unsigned char *hash)
 	return (write_in_full(fd, write_buffer, left) < 0) ? -1 : 0;
 }
 
-static void ce_smudge_racily_clean_entry(struct cache_entry *ce)
+static void ce_smudge_racily_clean_entry(struct index_state *istate,
+					 struct cache_entry *ce)
 {
 	/*
 	 * The only thing we care about in this function is to smudge the
@@ -2249,7 +2541,7 @@ static void ce_smudge_racily_clean_entry(struct cache_entry *ce)
 		return;
 	if (ce_match_stat_basic(ce, &st))
 		return;
-	if (ce_modified_check_fs(ce, &st)) {
+	if (ce_modified_check_fs(istate, ce, &st)) {
 		/* This is "racily clean"; smudge it.  Note that this
 		 * is a tricky code.  At first glance, it may appear
 		 * that it can break with this sequence:
@@ -2284,6 +2576,8 @@ static void copy_cache_entry_to_ondisk(struct ondisk_cache_entry *ondisk,
 				       struct cache_entry *ce)
 {
 	short flags;
+	const unsigned hashsz = the_hash_algo->rawsz;
+	uint16_t *flagsp = (uint16_t *)(ondisk->data + hashsz);
 
 	ondisk->ctime.sec = htonl(ce->ce_stat_data.sd_ctime.sec);
 	ondisk->mtime.sec = htonl(ce->ce_stat_data.sd_mtime.sec);
@@ -2295,15 +2589,13 @@ static void copy_cache_entry_to_ondisk(struct ondisk_cache_entry *ondisk,
 	ondisk->uid  = htonl(ce->ce_stat_data.sd_uid);
 	ondisk->gid  = htonl(ce->ce_stat_data.sd_gid);
 	ondisk->size = htonl(ce->ce_stat_data.sd_size);
-	hashcpy(ondisk->sha1, ce->oid.hash);
+	hashcpy(ondisk->data, ce->oid.hash);
 
 	flags = ce->ce_flags & ~CE_NAMEMASK;
 	flags |= (ce_namelen(ce) >= CE_NAMEMASK ? CE_NAMEMASK : ce_namelen(ce));
-	ondisk->flags = htons(flags);
+	flagsp[0] = htons(flags);
 	if (ce->ce_flags & CE_EXTENDED) {
-		struct ondisk_cache_entry_extended *ondisk2;
-		ondisk2 = (struct ondisk_cache_entry_extended *)ondisk;
-		ondisk2->flags2 = htons((ce->ce_flags & CE_EXTENDED_FLAGS) >> 16);
+		flagsp[1] = htons((ce->ce_flags & CE_EXTENDED_FLAGS) >> 16);
 	}
 }
 
@@ -2322,10 +2614,7 @@ static int ce_write_entry(git_hash_ctx *c, int fd, struct cache_entry *ce,
 		stripped_name = 1;
 	}
 
-	if (ce->ce_flags & CE_EXTENDED)
-		size = offsetof(struct ondisk_cache_entry_extended, name);
-	else
-		size = offsetof(struct ondisk_cache_entry, name);
+	size = offsetof(struct ondisk_cache_entry,data) + ondisk_data_size(ce->ce_flags, 0);
 
 	if (!previous_name) {
 		int len = ce_namelen(ce);
@@ -2395,7 +2684,7 @@ static int verify_index_from(const struct index_state *istate, const char *path)
 	if (n != the_hash_algo->rawsz)
 		goto out;
 
-	if (hashcmp(istate->oid.hash, hash))
+	if (!hasheq(istate->oid.hash, hash))
 		goto out;
 
 	close(fd);
@@ -2406,9 +2695,9 @@ out:
 	return 0;
 }
 
-static int verify_index(const struct index_state *istate)
+static int repo_verify_index(struct repository *repo)
 {
-	return verify_index_from(istate, get_index_file());
+	return verify_index_from(repo->index, repo->index_file);
 }
 
 static int has_racy_timestamp(struct index_state *istate)
@@ -2424,15 +2713,47 @@ static int has_racy_timestamp(struct index_state *istate)
 	return 0;
 }
 
-void update_index_if_able(struct index_state *istate, struct lock_file *lockfile)
+void repo_update_index_if_able(struct repository *repo,
+			       struct lock_file *lockfile)
 {
-	if ((istate->cache_changed || has_racy_timestamp(istate)) &&
-	    verify_index(istate))
-		write_locked_index(istate, lockfile, COMMIT_LOCK);
+	if ((repo->index->cache_changed ||
+	     has_racy_timestamp(repo->index)) &&
+	    repo_verify_index(repo))
+		write_locked_index(repo->index, lockfile, COMMIT_LOCK);
 	else
 		rollback_lock_file(lockfile);
 }
 
+static int record_eoie(void)
+{
+	int val;
+
+	if (!git_config_get_bool("index.recordendofindexentries", &val))
+		return val;
+
+	/*
+	 * As a convenience, the end of index entries extension
+	 * used for threading is written by default if the user
+	 * explicitly requested threaded index reads.
+	 */
+	return !git_config_get_index_threads(&val) && val != 1;
+}
+
+static int record_ieot(void)
+{
+	int val;
+
+	if (!git_config_get_bool("index.recordoffsettable", &val))
+		return val;
+
+	/*
+	 * As a convenience, the offset table used for threading is
+	 * written by default if the user explicitly requested
+	 * threaded index reads.
+	 */
+	return !git_config_get_index_threads(&val) && val != 1;
+}
+
 /*
  * On success, `tempfile` is closed. If it is the temporary file
  * of a `struct lock_file`, we will therefore effectively perform
@@ -2445,15 +2766,19 @@ static int do_write_index(struct index_state *istate, struct tempfile *tempfile,
 {
 	uint64_t start = getnanotime();
 	int newfd = tempfile->fd;
-	git_hash_ctx c;
+	git_hash_ctx c, eoie_c;
 	struct cache_header hdr;
 	int i, err = 0, removed, extended, hdr_version;
 	struct cache_entry **cache = istate->cache;
 	int entries = istate->cache_nr;
 	struct stat st;
-	struct ondisk_cache_entry_extended ondisk;
+	struct ondisk_cache_entry ondisk;
 	struct strbuf previous_name_buf = STRBUF_INIT, *previous_name;
 	int drop_cache_tree = istate->drop_cache_tree;
+	off_t offset;
+	int ieot_entries = 1;
+	struct index_entry_offset_table *ieot = NULL;
+	int nr, nr_threads;
 
 	for (i = removed = extended = 0; i < entries; i++) {
 		if (cache[i]->ce_flags & CE_REMOVE)
@@ -2468,7 +2793,7 @@ static int do_write_index(struct index_state *istate, struct tempfile *tempfile,
 	}
 
 	if (!istate->version) {
-		istate->version = get_index_format_default();
+		istate->version = get_index_format_default(the_repository);
 		if (git_env_bool("GIT_TEST_SPLIT_INDEX", 0))
 			init_split_index(istate);
 	}
@@ -2487,6 +2812,46 @@ static int do_write_index(struct index_state *istate, struct tempfile *tempfile,
 	if (ce_write(&c, newfd, &hdr, sizeof(hdr)) < 0)
 		return -1;
 
+	if (!HAVE_THREADS || git_config_get_index_threads(&nr_threads))
+		nr_threads = 1;
+
+	if (nr_threads != 1 && record_ieot()) {
+		int ieot_blocks, cpus;
+
+		/*
+		 * ensure default number of ieot blocks maps evenly to the
+		 * default number of threads that will process them leaving
+		 * room for the thread to load the index extensions.
+		 */
+		if (!nr_threads) {
+			ieot_blocks = istate->cache_nr / THREAD_COST;
+			cpus = online_cpus();
+			if (ieot_blocks > cpus - 1)
+				ieot_blocks = cpus - 1;
+		} else {
+			ieot_blocks = nr_threads;
+			if (ieot_blocks > istate->cache_nr)
+				ieot_blocks = istate->cache_nr;
+		}
+
+		/*
+		 * no reason to write out the IEOT extension if we don't
+		 * have enough blocks to utilize multi-threading
+		 */
+		if (ieot_blocks > 1) {
+			ieot = xcalloc(1, sizeof(struct index_entry_offset_table)
+				+ (ieot_blocks * sizeof(struct index_entry_offset)));
+			ieot_entries = DIV_ROUND_UP(entries, ieot_blocks);
+		}
+	}
+
+	offset = lseek(newfd, 0, SEEK_CUR);
+	if (offset < 0) {
+		free(ieot);
+		return -1;
+	}
+	offset += write_buffer_len;
+	nr = 0;
 	previous_name = (hdr_version == 4) ? &previous_name_buf : NULL;
 
 	for (i = 0; i < entries; i++) {
@@ -2494,7 +2859,7 @@ static int do_write_index(struct index_state *istate, struct tempfile *tempfile,
 		if (ce->ce_flags & CE_REMOVE)
 			continue;
 		if (!ce_uptodate(ce) && is_racy_timestamp(istate, ce))
-			ce_smudge_racily_clean_entry(ce);
+			ce_smudge_racily_clean_entry(istate, ce);
 		if (is_null_oid(&ce->oid)) {
 			static const char msg[] = "cache entry has null sha1: %s";
 			static int allow = -1;
@@ -2508,23 +2873,78 @@ static int do_write_index(struct index_state *istate, struct tempfile *tempfile,
 
 			drop_cache_tree = 1;
 		}
+		if (ieot && i && (i % ieot_entries == 0)) {
+			ieot->entries[ieot->nr].nr = nr;
+			ieot->entries[ieot->nr].offset = offset;
+			ieot->nr++;
+			/*
+			 * If we have a V4 index, set the first byte to an invalid
+			 * character to ensure there is nothing common with the previous
+			 * entry
+			 */
+			if (previous_name)
+				previous_name->buf[0] = 0;
+			nr = 0;
+			offset = lseek(newfd, 0, SEEK_CUR);
+			if (offset < 0) {
+				free(ieot);
+				return -1;
+			}
+			offset += write_buffer_len;
+		}
 		if (ce_write_entry(&c, newfd, ce, previous_name, (struct ondisk_cache_entry *)&ondisk) < 0)
 			err = -1;
 
 		if (err)
 			break;
+		nr++;
+	}
+	if (ieot && nr) {
+		ieot->entries[ieot->nr].nr = nr;
+		ieot->entries[ieot->nr].offset = offset;
+		ieot->nr++;
 	}
 	strbuf_release(&previous_name_buf);
 
-	if (err)
+	if (err) {
+		free(ieot);
 		return err;
+	}
 
 	/* Write extension data here */
-	if (!strip_extensions && istate->split_index) {
+	offset = lseek(newfd, 0, SEEK_CUR);
+	if (offset < 0) {
+		free(ieot);
+		return -1;
+	}
+	offset += write_buffer_len;
+	the_hash_algo->init_fn(&eoie_c);
+
+	/*
+	 * Lets write out CACHE_EXT_INDEXENTRYOFFSETTABLE first so that we
+	 * can minimize the number of extensions we have to scan through to
+	 * find it during load.  Write it out regardless of the
+	 * strip_extensions parameter as we need it when loading the shared
+	 * index.
+	 */
+	if (ieot) {
+		struct strbuf sb = STRBUF_INIT;
+
+		write_ieot_extension(&sb, ieot);
+		err = write_index_ext_header(&c, &eoie_c, newfd, CACHE_EXT_INDEXENTRYOFFSETTABLE, sb.len) < 0
+			|| ce_write(&c, newfd, sb.buf, sb.len) < 0;
+		strbuf_release(&sb);
+		free(ieot);
+		if (err)
+			return -1;
+	}
+
+	if (!strip_extensions && istate->split_index &&
+	    !is_null_oid(&istate->split_index->base_oid)) {
 		struct strbuf sb = STRBUF_INIT;
 
 		err = write_link_extension(&sb, istate) < 0 ||
-			write_index_ext_header(&c, newfd, CACHE_EXT_LINK,
+			write_index_ext_header(&c, &eoie_c, newfd, CACHE_EXT_LINK,
 					       sb.len) < 0 ||
 			ce_write(&c, newfd, sb.buf, sb.len) < 0;
 		strbuf_release(&sb);
@@ -2535,7 +2955,7 @@ static int do_write_index(struct index_state *istate, struct tempfile *tempfile,
 		struct strbuf sb = STRBUF_INIT;
 
 		cache_tree_write(&sb, istate->cache_tree);
-		err = write_index_ext_header(&c, newfd, CACHE_EXT_TREE, sb.len) < 0
+		err = write_index_ext_header(&c, &eoie_c, newfd, CACHE_EXT_TREE, sb.len) < 0
 			|| ce_write(&c, newfd, sb.buf, sb.len) < 0;
 		strbuf_release(&sb);
 		if (err)
@@ -2545,7 +2965,7 @@ static int do_write_index(struct index_state *istate, struct tempfile *tempfile,
 		struct strbuf sb = STRBUF_INIT;
 
 		resolve_undo_write(&sb, istate->resolve_undo);
-		err = write_index_ext_header(&c, newfd, CACHE_EXT_RESOLVE_UNDO,
+		err = write_index_ext_header(&c, &eoie_c, newfd, CACHE_EXT_RESOLVE_UNDO,
 					     sb.len) < 0
 			|| ce_write(&c, newfd, sb.buf, sb.len) < 0;
 		strbuf_release(&sb);
@@ -2556,7 +2976,7 @@ static int do_write_index(struct index_state *istate, struct tempfile *tempfile,
 		struct strbuf sb = STRBUF_INIT;
 
 		write_untracked_extension(&sb, istate->untracked);
-		err = write_index_ext_header(&c, newfd, CACHE_EXT_UNTRACKED,
+		err = write_index_ext_header(&c, &eoie_c, newfd, CACHE_EXT_UNTRACKED,
 					     sb.len) < 0 ||
 			ce_write(&c, newfd, sb.buf, sb.len) < 0;
 		strbuf_release(&sb);
@@ -2567,7 +2987,24 @@ static int do_write_index(struct index_state *istate, struct tempfile *tempfile,
 		struct strbuf sb = STRBUF_INIT;
 
 		write_fsmonitor_extension(&sb, istate);
-		err = write_index_ext_header(&c, newfd, CACHE_EXT_FSMONITOR, sb.len) < 0
+		err = write_index_ext_header(&c, &eoie_c, newfd, CACHE_EXT_FSMONITOR, sb.len) < 0
+			|| ce_write(&c, newfd, sb.buf, sb.len) < 0;
+		strbuf_release(&sb);
+		if (err)
+			return -1;
+	}
+
+	/*
+	 * CACHE_EXT_ENDOFINDEXENTRIES must be written as the last entry before the SHA1
+	 * so that it can be found and processed before all the index entries are
+	 * read.  Write it out regardless of the strip_extensions parameter as we need it
+	 * when loading the shared index.
+	 */
+	if (offset && record_eoie()) {
+		struct strbuf sb = STRBUF_INIT;
+
+		write_eoie_extension(&sb, &eoie_c, offset);
+		err = write_index_ext_header(&c, NULL, newfd, CACHE_EXT_ENDOFINDEXENTRIES, sb.len) < 0
 			|| ce_write(&c, newfd, sb.buf, sb.len) < 0;
 		strbuf_release(&sb);
 		if (err)
@@ -2577,14 +3014,24 @@ static int do_write_index(struct index_state *istate, struct tempfile *tempfile,
 	if (ce_flush(&c, newfd, istate->oid.hash))
 		return -1;
 	if (close_tempfile_gently(tempfile)) {
-		error(_("could not close '%s'"), tempfile->filename.buf);
+		error(_("could not close '%s'"), get_tempfile_path(tempfile));
 		return -1;
 	}
-	if (stat(tempfile->filename.buf, &st))
+	if (stat(get_tempfile_path(tempfile), &st))
 		return -1;
 	istate->timestamp.sec = (unsigned int)st.st_mtime;
 	istate->timestamp.nsec = ST_MTIME_NSEC(st);
 	trace_performance_since(start, "write index, changed mask = %x", istate->cache_changed);
+
+	/*
+	 * TODO trace2: replace "the_repository" with the actual repo instance
+	 * that is associated with the given "istate".
+	 */
+	trace2_data_intmax("index", the_repository, "write/version",
+			   istate->version);
+	trace2_data_intmax("index", the_repository, "write/cache_nr",
+			   istate->cache_nr);
+
 	return 0;
 }
 
@@ -2604,12 +3051,32 @@ static int commit_locked_index(struct lock_file *lk)
 static int do_write_locked_index(struct index_state *istate, struct lock_file *lock,
 				 unsigned flags)
 {
-	int ret = do_write_index(istate, lock->tempfile, 0);
+	int ret;
+
+	/*
+	 * TODO trace2: replace "the_repository" with the actual repo instance
+	 * that is associated with the given "istate".
+	 */
+	trace2_region_enter_printf("index", "do_write_index", the_repository,
+				   "%s", get_lock_file_path(lock));
+	ret = do_write_index(istate, lock->tempfile, 0);
+	trace2_region_leave_printf("index", "do_write_index", the_repository,
+				   "%s", get_lock_file_path(lock));
+
 	if (ret)
 		return ret;
 	if (flags & COMMIT_LOCK)
-		return commit_locked_index(lock);
-	return close_lock_file_gently(lock);
+		ret = commit_locked_index(lock);
+	else
+		ret = close_lock_file_gently(lock);
+
+	run_hook_le(NULL, "post-index-change",
+			istate->updated_workdir ? "1" : "0",
+			istate->updated_skipworktree ? "1" : "0", NULL);
+	istate->updated_workdir = 0;
+	istate->updated_skipworktree = 0;
+
+	return ret;
 }
 
 static int write_split_index(struct index_state *istate,
@@ -2689,12 +3156,18 @@ static int write_shared_index(struct index_state *istate,
 	int ret;
 
 	move_cache_to_base_index(istate);
+
+	trace2_region_enter_printf("index", "shared/do_write_index",
+				   the_repository, "%s", get_tempfile_path(*temp));
 	ret = do_write_index(si->base, *temp, 1);
+	trace2_region_leave_printf("index", "shared/do_write_index",
+				   the_repository, "%s", get_tempfile_path(*temp));
+
 	if (ret)
 		return ret;
 	ret = adjust_shared_perm(get_tempfile_path(*temp));
 	if (ret) {
-		error("cannot fix permission bits on %s", get_tempfile_path(*temp));
+		error(_("cannot fix permission bits on '%s'"), get_tempfile_path(*temp));
 		return ret;
 	}
 	ret = rename_tempfile(temp,
@@ -2743,6 +3216,9 @@ int write_locked_index(struct index_state *istate, struct lock_file *lock,
 	int new_shared_index, ret;
 	struct split_index *si = istate->split_index;
 
+	if (git_env_bool("GIT_TEST_CHECK_CACHE_TREE", 0))
+		cache_tree_verify(the_repository, istate);
+
 	if ((flags & SKIP_IF_UNCHANGED) && !istate->cache_changed) {
 		if (flags & COMMIT_LOCK)
 			rollback_lock_file(lock);
@@ -2774,7 +3250,8 @@ int write_locked_index(struct index_state *istate, struct lock_file *lock,
 		struct tempfile *temp;
 		int saved_errno;
 
-		temp = mks_tempfile(git_path("sharedindex_XXXXXX"));
+		/* Same initial permissions as the main .git/index file */
+		temp = mks_tempfile_sm(git_path("sharedindex_XXXXXX"), 0, 0666);
 		if (!temp) {
 			oidclr(&si->base_oid);
 			ret = do_write_locked_index(istate, lock, flags);
@@ -2794,7 +3271,7 @@ int write_locked_index(struct index_state *istate, struct lock_file *lock,
 	ret = write_split_index(istate, lock, flags);
 
 	/* Freshen the shared index only if the split-index was written */
-	if (!ret && !new_shared_index) {
+	if (!ret && !new_shared_index && !is_null_oid(&si->base_oid)) {
 		const char *shared_index = git_path("sharedindex.%s",
 						    oid_to_hex(&si->base_oid));
 		freshen_shared_index(shared_index, 1);
@@ -2816,12 +3293,14 @@ out:
  * state can call this and check its return value, instead of calling
  * read_cache().
  */
-int read_index_unmerged(struct index_state *istate)
+int repo_read_index_unmerged(struct repository *repo)
 {
+	struct index_state *istate;
 	int i;
 	int unmerged = 0;
 
-	read_index(istate);
+	repo_read_index(repo);
+	istate = repo->index;
 	for (i = 0; i < istate->cache_nr; i++) {
 		struct cache_entry *ce = istate->cache[i];
 		struct cache_entry *new_ce;
@@ -2837,7 +3316,7 @@ int read_index_unmerged(struct index_state *istate)
 		new_ce->ce_namelen = len;
 		new_ce->ce_mode = ce->ce_mode;
 		if (add_index_entry(istate, new_ce, ADD_CACHE_SKIP_DFCHECK))
-			return error("%s: cannot drop to stage #0",
+			return error(_("%s: cannot drop to stage #0"),
 				     new_ce->name);
 	}
 	return unmerged;
@@ -2939,6 +3418,8 @@ void move_index_extensions(struct index_state *dst, struct index_state *src)
 {
 	dst->untracked = src->untracked;
 	src->untracked = NULL;
+	dst->cache_tree = src->cache_tree;
+	src->cache_tree = NULL;
 }
 
 struct cache_entry *dup_cache_entry(const struct cache_entry *ce,
@@ -2978,3 +3459,179 @@ int should_validate_cache_entries(void)
 
 	return validate_index_cache_entries;
 }
+
+#define EOIE_SIZE (4 + GIT_SHA1_RAWSZ) /* <4-byte offset> + <20-byte hash> */
+#define EOIE_SIZE_WITH_HEADER (4 + 4 + EOIE_SIZE) /* <4-byte signature> + <4-byte length> + EOIE_SIZE */
+
+static size_t read_eoie_extension(const char *mmap, size_t mmap_size)
+{
+	/*
+	 * The end of index entries (EOIE) extension is guaranteed to be last
+	 * so that it can be found by scanning backwards from the EOF.
+	 *
+	 * "EOIE"
+	 * <4-byte length>
+	 * <4-byte offset>
+	 * <20-byte hash>
+	 */
+	const char *index, *eoie;
+	uint32_t extsize;
+	size_t offset, src_offset;
+	unsigned char hash[GIT_MAX_RAWSZ];
+	git_hash_ctx c;
+
+	/* ensure we have an index big enough to contain an EOIE extension */
+	if (mmap_size < sizeof(struct cache_header) + EOIE_SIZE_WITH_HEADER + the_hash_algo->rawsz)
+		return 0;
+
+	/* validate the extension signature */
+	index = eoie = mmap + mmap_size - EOIE_SIZE_WITH_HEADER - the_hash_algo->rawsz;
+	if (CACHE_EXT(index) != CACHE_EXT_ENDOFINDEXENTRIES)
+		return 0;
+	index += sizeof(uint32_t);
+
+	/* validate the extension size */
+	extsize = get_be32(index);
+	if (extsize != EOIE_SIZE)
+		return 0;
+	index += sizeof(uint32_t);
+
+	/*
+	 * Validate the offset we're going to look for the first extension
+	 * signature is after the index header and before the eoie extension.
+	 */
+	offset = get_be32(index);
+	if (mmap + offset < mmap + sizeof(struct cache_header))
+		return 0;
+	if (mmap + offset >= eoie)
+		return 0;
+	index += sizeof(uint32_t);
+
+	/*
+	 * The hash is computed over extension types and their sizes (but not
+	 * their contents).  E.g. if we have "TREE" extension that is N-bytes
+	 * long, "REUC" extension that is M-bytes long, followed by "EOIE",
+	 * then the hash would be:
+	 *
+	 * SHA-1("TREE" + <binary representation of N> +
+	 *	 "REUC" + <binary representation of M>)
+	 */
+	src_offset = offset;
+	the_hash_algo->init_fn(&c);
+	while (src_offset < mmap_size - the_hash_algo->rawsz - EOIE_SIZE_WITH_HEADER) {
+		/* After an array of active_nr index entries,
+		 * there can be arbitrary number of extended
+		 * sections, each of which is prefixed with
+		 * extension name (4-byte) and section length
+		 * in 4-byte network byte order.
+		 */
+		uint32_t extsize;
+		memcpy(&extsize, mmap + src_offset + 4, 4);
+		extsize = ntohl(extsize);
+
+		/* verify the extension size isn't so large it will wrap around */
+		if (src_offset + 8 + extsize < src_offset)
+			return 0;
+
+		the_hash_algo->update_fn(&c, mmap + src_offset, 8);
+
+		src_offset += 8;
+		src_offset += extsize;
+	}
+	the_hash_algo->final_fn(hash, &c);
+	if (!hasheq(hash, (const unsigned char *)index))
+		return 0;
+
+	/* Validate that the extension offsets returned us back to the eoie extension. */
+	if (src_offset != mmap_size - the_hash_algo->rawsz - EOIE_SIZE_WITH_HEADER)
+		return 0;
+
+	return offset;
+}
+
+static void write_eoie_extension(struct strbuf *sb, git_hash_ctx *eoie_context, size_t offset)
+{
+	uint32_t buffer;
+	unsigned char hash[GIT_MAX_RAWSZ];
+
+	/* offset */
+	put_be32(&buffer, offset);
+	strbuf_add(sb, &buffer, sizeof(uint32_t));
+
+	/* hash */
+	the_hash_algo->final_fn(hash, eoie_context);
+	strbuf_add(sb, hash, the_hash_algo->rawsz);
+}
+
+#define IEOT_VERSION	(1)
+
+static struct index_entry_offset_table *read_ieot_extension(const char *mmap, size_t mmap_size, size_t offset)
+{
+	const char *index = NULL;
+	uint32_t extsize, ext_version;
+	struct index_entry_offset_table *ieot;
+	int i, nr;
+
+	/* find the IEOT extension */
+	if (!offset)
+		return NULL;
+	while (offset <= mmap_size - the_hash_algo->rawsz - 8) {
+		extsize = get_be32(mmap + offset + 4);
+		if (CACHE_EXT((mmap + offset)) == CACHE_EXT_INDEXENTRYOFFSETTABLE) {
+			index = mmap + offset + 4 + 4;
+			break;
+		}
+		offset += 8;
+		offset += extsize;
+	}
+	if (!index)
+		return NULL;
+
+	/* validate the version is IEOT_VERSION */
+	ext_version = get_be32(index);
+	if (ext_version != IEOT_VERSION) {
+		error("invalid IEOT version %d", ext_version);
+		return NULL;
+	}
+	index += sizeof(uint32_t);
+
+	/* extension size - version bytes / bytes per entry */
+	nr = (extsize - sizeof(uint32_t)) / (sizeof(uint32_t) + sizeof(uint32_t));
+	if (!nr) {
+		error("invalid number of IEOT entries %d", nr);
+		return NULL;
+	}
+	ieot = xmalloc(sizeof(struct index_entry_offset_table)
+		       + (nr * sizeof(struct index_entry_offset)));
+	ieot->nr = nr;
+	for (i = 0; i < nr; i++) {
+		ieot->entries[i].offset = get_be32(index);
+		index += sizeof(uint32_t);
+		ieot->entries[i].nr = get_be32(index);
+		index += sizeof(uint32_t);
+	}
+
+	return ieot;
+}
+
+static void write_ieot_extension(struct strbuf *sb, struct index_entry_offset_table *ieot)
+{
+	uint32_t buffer;
+	int i;
+
+	/* version */
+	put_be32(&buffer, IEOT_VERSION);
+	strbuf_add(sb, &buffer, sizeof(uint32_t));
+
+	/* ieot */
+	for (i = 0; i < ieot->nr; i++) {
+
+		/* offset */
+		put_be32(&buffer, ieot->entries[i].offset);
+		strbuf_add(sb, &buffer, sizeof(uint32_t));
+
+		/* count */
+		put_be32(&buffer, ieot->entries[i].nr);
+		strbuf_add(sb, &buffer, sizeof(uint32_t));
+	}
+}