Merge branch 'rs/obsd-getcwd-workaround' into next
[gitweb.git] / read-cache.c
index d9fb78bc559ac9de642833df5af63e33481cad52..acfb028f480b5545aa82d5c0533fe8bdfc581dfd 100644 (file)
@@ -5,6 +5,7 @@
  */
 #define NO_THE_INDEX_COMPATIBILITY_MACROS
 #include "cache.h"
+#include "config.h"
 #include "tempfile.h"
 #include "lockfile.h"
 #include "cache-tree.h"
@@ -19,9 +20,6 @@
 #include "split-index.h"
 #include "utf8.h"
 
-static struct cache_entry *refresh_cache_entry(struct cache_entry *ce,
-                                              unsigned int options);
-
 /* Mask for the name length in ce_flags in the on-disk index */
 
 #define CE_NAMEMASK  (0x0fff)
@@ -159,12 +157,12 @@ void fill_stat_cache_info(struct cache_entry *ce, struct stat *st)
 static int ce_compare_data(const struct cache_entry *ce, struct stat *st)
 {
        int match = -1;
-       int fd = open(ce->name, O_RDONLY);
+       int fd = git_open_cloexec(ce->name, O_RDONLY);
 
        if (fd >= 0) {
                unsigned char sha1[20];
                if (!index_fd(sha1, fd, st, OBJ_BLOB, ce->name, 0))
-                       match = hashcmp(sha1, ce->sha1);
+                       match = hashcmp(sha1, ce->oid.hash);
                /* index_fd() closed the file descriptor already */
        }
        return match;
@@ -181,7 +179,7 @@ static int ce_compare_link(const struct cache_entry *ce, size_t expected_size)
        if (strbuf_readlink(&sb, ce->name, expected_size))
                return -1;
 
-       buffer = read_sha1_file(ce->sha1, &type, &size);
+       buffer = read_sha1_file(ce->oid.hash, &type, &size);
        if (buffer) {
                if (size == sb.len)
                        match = memcmp(buffer, sb.buf, size);
@@ -205,7 +203,7 @@ static int ce_compare_gitlink(const struct cache_entry *ce)
         */
        if (resolve_gitlink_ref(ce->name, "HEAD", sha1) < 0)
                return 0;
-       return hashcmp(sha1, ce->sha1);
+       return hashcmp(sha1, ce->oid.hash);
 }
 
 static int ce_modified_check_fs(const struct cache_entry *ce, struct stat *st)
@@ -265,7 +263,7 @@ static int ce_match_stat_basic(const struct cache_entry *ce, struct stat *st)
 
        /* Racily smudged entry? */
        if (!ce->ce_stat_data.sd_size) {
-               if (!is_empty_blob_sha1(ce->sha1))
+               if (!is_empty_blob_sha1(ce->oid.hash))
                        changed |= DATA_CHANGED;
        }
 
@@ -506,7 +504,6 @@ int index_name_pos(const struct index_state *istate, const char *name, int namel
        return index_name_stage_pos(istate, name, namelen, 0);
 }
 
-/* Remove entry, return true if there are more entries to go.. */
 int remove_index_entry_at(struct index_state *istate, int pos)
 {
        struct cache_entry *ce = istate->cache[pos];
@@ -518,9 +515,8 @@ int remove_index_entry_at(struct index_state *istate, int pos)
        istate->cache_nr--;
        if (pos >= istate->cache_nr)
                return 0;
-       memmove(istate->cache + pos,
-               istate->cache + pos + 1,
-               (istate->cache_nr - pos) * sizeof(struct cache_entry *));
+       MOVE_ARRAY(istate->cache + pos, istate->cache + pos + 1,
+                  istate->cache_nr - pos);
        return 1;
 }
 
@@ -627,7 +623,7 @@ void set_object_name_for_intent_to_add_entry(struct cache_entry *ce)
        unsigned char sha1[20];
        if (write_sha1_file("", 0, blob_type, sha1))
                die("cannot create an empty blob in the object database");
-       hashcpy(ce->sha1, sha1);
+       hashcpy(ce->oid.hash, sha1);
 }
 
 int add_to_index(struct index_state *istate, const char *path, struct stat *st, int flags)
@@ -659,9 +655,10 @@ int add_to_index(struct index_state *istate, const char *path, struct stat *st,
        else
                ce->ce_flags |= CE_INTENT_TO_ADD;
 
-       if (trust_executable_bit && has_symlinks)
+
+       if (trust_executable_bit && has_symlinks) {
                ce->ce_mode = create_ce_mode(st_mode);
-       else {
+       else {
                /* If there is an existing entry, pick the mode bits and type
                 * from it, otherwise assume unexecutable regular file.
                 */
@@ -692,7 +689,7 @@ int add_to_index(struct index_state *istate, const char *path, struct stat *st,
                return 0;
        }
        if (!intent_only) {
-               if (index_path(ce->sha1, path, st, HASH_WRITE_OBJECT)) {
+               if (index_path(ce->oid.hash, path, st, HASH_WRITE_OBJECT)) {
                        free(ce);
                        return error("unable to index file %s", path);
                }
@@ -706,7 +703,7 @@ 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) &&
-                   !hashcmp(alias->sha1, ce->sha1) &&
+                   !oidcmp(&alias->oid, &ce->oid) &&
                    ce->ce_mode == alias->ce_mode);
 
        if (pretend)
@@ -744,7 +741,7 @@ struct cache_entry *make_cache_entry(unsigned int mode,
        size = cache_entry_size(len);
        ce = xcalloc(1, size);
 
-       hashcpy(ce->sha1, sha1);
+       hashcpy(ce->oid.hash, sha1);
        memcpy(ce->name, path, len);
        ce->ce_flags = create_ce_flags(stage);
        ce->ce_namelen = len;
@@ -756,6 +753,35 @@ struct cache_entry *make_cache_entry(unsigned int mode,
        return ret;
 }
 
+/*
+ * Chmod an index entry with either +x or -x.
+ *
+ * Returns -1 if the chmod for the particular cache entry failed (if it's
+ * not a regular file), -2 if an invalid flip argument is passed in, 0
+ * otherwise.
+ */
+int chmod_index_entry(struct index_state *istate, struct cache_entry *ce,
+                     char flip)
+{
+       if (!S_ISREG(ce->ce_mode))
+               return -1;
+       switch (flip) {
+       case '+':
+               ce->ce_mode |= 0111;
+               break;
+       case '-':
+               ce->ce_mode &= ~0111;
+               break;
+       default:
+               return -2;
+       }
+       cache_tree_invalidate_path(istate, ce->name);
+       ce->ce_flags |= CE_UPDATE_IN_BASE;
+       istate->cache_changed |= CE_ENTRY_CHANGED;
+
+       return 0;
+}
+
 int ce_same_name(const struct cache_entry *a, const struct cache_entry *b)
 {
        int len = ce_namelen(a);
@@ -861,9 +887,32 @@ static int has_file_name(struct index_state *istate,
        return retval;
 }
 
+
+/*
+ * Like strcmp(), but also return the offset of the first change.
+ * If strings are equal, return the length.
+ */
+int strcmp_offset(const char *s1, const char *s2, size_t *first_change)
+{
+       size_t k;
+
+       if (!first_change)
+               return strcmp(s1, s2);
+
+       for (k = 0; s1[k] == s2[k]; k++)
+               if (s1[k] == '\0')
+                       break;
+
+       *first_change = k;
+       return (unsigned char)s1[k] - (unsigned char)s2[k];
+}
+
 /*
  * Do we have another file with a pathname that is a proper
  * subset of the name we're trying to add?
+ *
+ * That is, is there another file in the index with a path
+ * that matches a sub-directory in the given entry?
  */
 static int has_dir_name(struct index_state *istate,
                        const struct cache_entry *ce, int pos, int ok_to_replace)
@@ -872,9 +921,51 @@ static int has_dir_name(struct index_state *istate,
        int stage = ce_stage(ce);
        const char *name = ce->name;
        const char *slash = name + ce_namelen(ce);
+       size_t len_eq_last;
+       int cmp_last = 0;
+
+       /*
+        * We are frequently called during an iteration on a sorted
+        * list of pathnames and while building a new index.  Therefore,
+        * there is a high probability that this entry will eventually
+        * be appended to the index, rather than inserted in the middle.
+        * If we can confirm that, we can avoid binary searches on the
+        * components of the pathname.
+        *
+        * Compare the entry's full path with the last path in the index.
+        */
+       if (istate->cache_nr > 0) {
+               cmp_last = strcmp_offset(name,
+                       istate->cache[istate->cache_nr - 1]->name,
+                       &len_eq_last);
+               if (cmp_last > 0) {
+                       if (len_eq_last == 0) {
+                               /*
+                                * The entry sorts AFTER the last one in the
+                                * index and their paths have no common prefix,
+                                * so there cannot be a F/D conflict.
+                                */
+                               return retval;
+                       } else {
+                               /*
+                                * The entry sorts AFTER the last one in the
+                                * index, but has a common prefix.  Fall through
+                                * to the loop below to disect the entry's path
+                                * and see where the difference is.
+                                */
+                       }
+               } else if (cmp_last == 0) {
+                       /*
+                        * The entry exactly matches the last one in the
+                        * index, but because of multiple stage and CE_REMOVE
+                        * items, we fall through and let the regular search
+                        * code handle it.
+                        */
+               }
+       }
 
        for (;;) {
-               int len;
+               size_t len;
 
                for (;;) {
                        if (*--slash == '/')
@@ -884,6 +975,67 @@ static int has_dir_name(struct index_state *istate,
                }
                len = slash - name;
 
+               if (cmp_last > 0) {
+                       /*
+                        * (len + 1) is a directory boundary (including
+                        * the trailing slash).  And since the loop is
+                        * decrementing "slash", the first iteration is
+                        * the longest directory prefix; subsequent
+                        * iterations consider parent directories.
+                        */
+
+                       if (len + 1 <= len_eq_last) {
+                               /*
+                                * The directory prefix (including the trailing
+                                * slash) also appears as a prefix in the last
+                                * entry, so the remainder cannot collide (because
+                                * strcmp said the whole path was greater).
+                                *
+                                * EQ: last: xxx/A
+                                *     this: xxx/B
+                                *
+                                * LT: last: xxx/file_A
+                                *     this: xxx/file_B
+                                */
+                               return retval;
+                       }
+
+                       if (len > len_eq_last) {
+                               /*
+                                * This part of the directory prefix (excluding
+                                * the trailing slash) is longer than the known
+                                * equal portions, so this sub-directory cannot
+                                * collide with a file.
+                                *
+                                * GT: last: xxxA
+                                *     this: xxxB/file
+                                */
+                               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.
+                        *
+                        * last: xxx
+                        * this: xxx/file
+                        */
+               }
+
                pos = index_name_stage_pos(istate, name, len, stage);
                if (pos >= 0) {
                        /*
@@ -975,7 +1127,16 @@ static int add_index_entry_with_check(struct index_state *istate, struct cache_e
 
        if (!(option & ADD_CACHE_KEEP_CACHE_TREE))
                cache_tree_invalidate_path(istate, ce->name);
-       pos = index_name_stage_pos(istate, ce->name, ce_namelen(ce), ce_stage(ce));
+
+       /*
+        * If this entry's path sorts after the last entry in the index,
+        * we can avoid searching for it.
+        */
+       if (istate->cache_nr > 0 &&
+               strcmp(ce->name, istate->cache[istate->cache_nr - 1]->name) > 0)
+               pos = -istate->cache_nr - 1;
+       else
+               pos = index_name_stage_pos(istate, ce->name, ce_namelen(ce), ce_stage(ce));
 
        /* existing match? Just replace it. */
        if (pos >= 0) {
@@ -1254,7 +1415,7 @@ int refresh_index(struct index_state *istate, unsigned int flags,
        return has_errors;
 }
 
-static struct cache_entry *refresh_cache_entry(struct cache_entry *ce,
+struct cache_entry *refresh_cache_entry(struct cache_entry *ce,
                                               unsigned int options)
 {
        return refresh_cache_ent(&the_index, ce, options, NULL, NULL);
@@ -1345,6 +1506,9 @@ struct ondisk_cache_entry_extended {
                            ondisk_cache_entry_extended_size(ce_namelen(ce)) : \
                            ondisk_cache_entry_size(ce_namelen(ce)))
 
+/* Allow fsck to force verification of the index checksum. */
+int verify_index_checksum;
+
 static int verify_hdr(struct cache_header *hdr, unsigned long size)
 {
        git_SHA_CTX c;
@@ -1356,6 +1520,10 @@ static int verify_hdr(struct cache_header *hdr, unsigned long size)
        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);
+
+       if (!verify_index_checksum)
+               return 0;
+
        git_SHA1_Init(&c);
        git_SHA1_Update(&c, hdr, size - 20);
        git_SHA1_Final(sha1, &c);
@@ -1391,12 +1559,9 @@ static int read_index_extension(struct index_state *istate,
        return 0;
 }
 
-int hold_locked_index(struct lock_file *lk, int die_on_error)
+int hold_locked_index(struct lock_file *lk, int lock_flags)
 {
-       return hold_lock_file_for_update(lk, get_index_file(),
-                                        die_on_error
-                                        ? LOCK_DIE_ON_ERROR
-                                        : 0);
+       return hold_lock_file_for_update(lk, get_index_file(), lock_flags);
 }
 
 int read_index(struct index_state *istate)
@@ -1424,7 +1589,7 @@ static struct cache_entry *cache_entry_from_ondisk(struct ondisk_cache_entry *on
        ce->ce_flags = flags & ~CE_NAMEMASK;
        ce->ce_namelen = len;
        ce->index = 0;
-       hashcpy(ce->sha1, ondisk->sha1);
+       hashcpy(ce->oid.hash, ondisk->sha1);
        memcpy(ce->name, name, len);
        ce->name[len] = '\0';
        return ce;
@@ -1535,10 +1700,27 @@ static void tweak_untracked_cache(struct index_state *istate)
        }
 }
 
+static void tweak_split_index(struct index_state *istate)
+{
+       switch (git_config_get_split_index()) {
+       case -1: /* unset: do nothing */
+               break;
+       case 0: /* false */
+               remove_split_index(istate);
+               break;
+       case 1: /* true */
+               add_split_index(istate);
+               break;
+       default: /* unknown value: do nothing */
+               break;
+       }
+}
+
 static void post_read_index_from(struct index_state *istate)
 {
        check_ce_order(istate);
        tweak_untracked_cache(istate);
+       tweak_split_index(istate);
 }
 
 /* remember to discard_cache() before reading a different cache! */
@@ -1634,10 +1816,26 @@ int do_read_index(struct index_state *istate, const char *path, int must_exist)
        die("index file corrupt");
 }
 
+/*
+ * Signal that the shared index is used by updating its mtime.
+ *
+ * This way, shared index can be removed if they have not been used
+ * for some time.
+ */
+static void freshen_shared_index(char *base_sha1_hex, int warn)
+{
+       char *shared_index = git_pathdup("sharedindex.%s", base_sha1_hex);
+       if (!check_and_freshen_file(shared_index, 1) && warn)
+               warning("could not freshen shared index '%s'", shared_index);
+       free(shared_index);
+}
+
 int read_index_from(struct index_state *istate, const char *path)
 {
        struct split_index *split_index;
        int ret;
+       char *base_sha1_hex;
+       const char *base_path;
 
        /* istate->initialized covers both .git/index and .git/sharedindex.xxx */
        if (istate->initialized)
@@ -1655,15 +1853,16 @@ int read_index_from(struct index_state *istate, const char *path)
                discard_index(split_index->base);
        else
                split_index->base = xcalloc(1, sizeof(*split_index->base));
-       ret = do_read_index(split_index->base,
-                           git_path("sharedindex.%s",
-                                    sha1_to_hex(split_index->base_sha1)), 1);
+
+       base_sha1_hex = sha1_to_hex(split_index->base_sha1);
+       base_path = git_path("sharedindex.%s", base_sha1_hex);
+       ret = do_read_index(split_index->base, base_path, 1);
        if (hashcmp(split_index->base_sha1, split_index->base->sha1))
                die("broken index, expect %s in %s, got %s",
-                   sha1_to_hex(split_index->base_sha1),
-                   git_path("sharedindex.%s",
-                            sha1_to_hex(split_index->base_sha1)),
+                   base_sha1_hex, base_path,
                    sha1_to_hex(split_index->base->sha1));
+
+       freshen_shared_index(base_sha1_hex, 0);
        merge_base_index(istate);
        post_read_index_from(istate);
        return ret;
@@ -1695,8 +1894,7 @@ int discard_index(struct index_state *istate)
        free_name_hash(istate);
        cache_tree_free(&(istate->cache_tree));
        istate->initialized = 0;
-       free(istate->cache);
-       istate->cache = NULL;
+       FREE_AND_NULL(istate->cache);
        istate->cache_alloc = 0;
        discard_split_index(istate);
        free_untracked_cache(istate->untracked);
@@ -1849,7 +2047,7 @@ static char *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->sha1);
+       hashcpy(ondisk->sha1, ce->oid.hash);
 
        flags = ce->ce_flags & ~CE_NAMEMASK;
        flags |= (ce_namelen(ce) >= CE_NAMEMASK ? CE_NAMEMASK : ce_namelen(ce));
@@ -1988,9 +2186,10 @@ void update_index_if_able(struct index_state *istate, struct lock_file *lockfile
                rollback_lock_file(lockfile);
 }
 
-static int do_write_index(struct index_state *istate, int newfd,
+static int do_write_index(struct index_state *istate, struct tempfile *tempfile,
                          int strip_extensions)
 {
+       int newfd = tempfile->fd;
        git_SHA_CTX c;
        struct cache_header hdr;
        int i, err, removed, extended, hdr_version;
@@ -1998,6 +2197,7 @@ static int do_write_index(struct index_state *istate, int newfd,
        int entries = istate->cache_nr;
        struct stat st;
        struct strbuf previous_name_buf = STRBUF_INIT, *previous_name;
+       int drop_cache_tree = 0;
 
        for (i = removed = extended = 0; i < entries; i++) {
                if (cache[i]->ce_flags & CE_REMOVE)
@@ -2038,7 +2238,7 @@ static int do_write_index(struct index_state *istate, int newfd,
                        continue;
                if (!ce_uptodate(ce) && is_racy_timestamp(istate, ce))
                        ce_smudge_racily_clean_entry(ce);
-               if (is_null_sha1(ce->sha1)) {
+               if (is_null_oid(&ce->oid)) {
                        static const char msg[] = "cache entry has null sha1: %s";
                        static int allow = -1;
 
@@ -2048,6 +2248,8 @@ static int do_write_index(struct index_state *istate, int newfd,
                                warning(msg, ce->name);
                        else
                                return error(msg, ce->name);
+
+                       drop_cache_tree = 1;
                }
                if (ce_write_entry(&c, newfd, ce, previous_name) < 0)
                        return -1;
@@ -2066,7 +2268,7 @@ static int do_write_index(struct index_state *istate, int newfd,
                if (err)
                        return -1;
        }
-       if (!strip_extensions && istate->cache_tree) {
+       if (!strip_extensions && !drop_cache_tree && istate->cache_tree) {
                struct strbuf sb = STRBUF_INIT;
 
                cache_tree_write(&sb, istate->cache_tree);
@@ -2099,7 +2301,11 @@ static int do_write_index(struct index_state *istate, int newfd,
                        return -1;
        }
 
-       if (ce_flush(&c, newfd, istate->sha1) || fstat(newfd, &st))
+       if (ce_flush(&c, newfd, istate->sha1))
+               return -1;
+       if (close_tempfile(tempfile))
+               return error(_("could not close '%s'"), tempfile->filename.buf);
+       if (stat(tempfile->filename.buf, &st))
                return -1;
        istate->timestamp.sec = (unsigned int)st.st_mtime;
        istate->timestamp.nsec = ST_MTIME_NSEC(st);
@@ -2122,7 +2328,7 @@ 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, get_lock_file_fd(lock), 0);
+       int ret = do_write_index(istate, &lock->tempfile, 0);
        if (ret)
                return ret;
        assert((flags & (COMMIT_LOCK | CLOSE_LOCK)) !=
@@ -2146,6 +2352,65 @@ static int write_split_index(struct index_state *istate,
        return ret;
 }
 
+static const char *shared_index_expire = "2.weeks.ago";
+
+static unsigned long get_shared_index_expire_date(void)
+{
+       static unsigned long shared_index_expire_date;
+       static int shared_index_expire_date_prepared;
+
+       if (!shared_index_expire_date_prepared) {
+               git_config_get_expiry("splitindex.sharedindexexpire",
+                                     &shared_index_expire);
+               shared_index_expire_date = approxidate(shared_index_expire);
+               shared_index_expire_date_prepared = 1;
+       }
+
+       return shared_index_expire_date;
+}
+
+static int should_delete_shared_index(const char *shared_index_path)
+{
+       struct stat st;
+       unsigned long expiration;
+
+       /* Check timestamp */
+       expiration = get_shared_index_expire_date();
+       if (!expiration)
+               return 0;
+       if (stat(shared_index_path, &st))
+               return error_errno(_("could not stat '%s'"), shared_index_path);
+       if (st.st_mtime > expiration)
+               return 0;
+
+       return 1;
+}
+
+static int clean_shared_index_files(const char *current_hex)
+{
+       struct dirent *de;
+       DIR *dir = opendir(get_git_dir());
+
+       if (!dir)
+               return error_errno(_("unable to open git dir: %s"), get_git_dir());
+
+       while ((de = readdir(dir)) != NULL) {
+               const char *sha1_hex;
+               const char *shared_index_path;
+               if (!skip_prefix(de->d_name, "sharedindex.", &sha1_hex))
+                       continue;
+               if (!strcmp(sha1_hex, current_hex))
+                       continue;
+               shared_index_path = git_path("%s", de->d_name);
+               if (should_delete_shared_index(shared_index_path) > 0 &&
+                   unlink(shared_index_path))
+                       warning_errno(_("unable to unlink: %s"), shared_index_path);
+       }
+       closedir(dir);
+
+       return 0;
+}
+
 static struct tempfile temporary_sharedindex;
 
 static int write_shared_index(struct index_state *istate,
@@ -2160,21 +2425,63 @@ static int write_shared_index(struct index_state *istate,
                return do_write_locked_index(istate, lock, flags);
        }
        move_cache_to_base_index(istate);
-       ret = do_write_index(si->base, fd, 1);
+       ret = do_write_index(si->base, &temporary_sharedindex, 1);
        if (ret) {
                delete_tempfile(&temporary_sharedindex);
                return ret;
        }
+       ret = adjust_shared_perm(get_tempfile_path(&temporary_sharedindex));
+       if (ret) {
+               int save_errno = errno;
+               error("cannot fix permission bits on %s", get_tempfile_path(&temporary_sharedindex));
+               delete_tempfile(&temporary_sharedindex);
+               errno = save_errno;
+               return ret;
+       }
        ret = rename_tempfile(&temporary_sharedindex,
                              git_path("sharedindex.%s", sha1_to_hex(si->base->sha1)));
-       if (!ret)
+       if (!ret) {
                hashcpy(si->base_sha1, si->base->sha1);
+               clean_shared_index_files(sha1_to_hex(si->base->sha1));
+       }
+
        return ret;
 }
 
+static const int default_max_percent_split_change = 20;
+
+static int too_many_not_shared_entries(struct index_state *istate)
+{
+       int i, not_shared = 0;
+       int max_split = git_config_get_max_percent_split_change();
+
+       switch (max_split) {
+       case -1:
+               /* not or badly configured: use the default value */
+               max_split = default_max_percent_split_change;
+               break;
+       case 0:
+               return 1; /* 0% means always write a new shared index */
+       case 100:
+               return 0; /* 100% means never write a new shared index */
+       default:
+               break; /* just use the configured value */
+       }
+
+       /* Count not shared entries */
+       for (i = 0; i < istate->cache_nr; i++) {
+               struct cache_entry *ce = istate->cache[i];
+               if (!ce->index)
+                       not_shared++;
+       }
+
+       return (int64_t)istate->cache_nr * max_split < (int64_t)not_shared * 100;
+}
+
 int write_locked_index(struct index_state *istate, struct lock_file *lock,
                       unsigned flags)
 {
+       int new_shared_index, ret;
        struct split_index *si = istate->split_index;
 
        if (!si || alternate_index_output ||
@@ -2189,13 +2496,24 @@ int write_locked_index(struct index_state *istate, struct lock_file *lock,
                if ((v & 15) < 6)
                        istate->cache_changed |= SPLIT_INDEX_ORDERED;
        }
-       if (istate->cache_changed & SPLIT_INDEX_ORDERED) {
-               int ret = write_shared_index(istate, lock, flags);
+       if (too_many_not_shared_entries(istate))
+               istate->cache_changed |= SPLIT_INDEX_ORDERED;
+
+       new_shared_index = istate->cache_changed & SPLIT_INDEX_ORDERED;
+
+       if (new_shared_index) {
+               ret = write_shared_index(istate, lock, flags);
                if (ret)
                        return ret;
        }
 
-       return write_split_index(istate, lock, flags);
+       ret = write_split_index(istate, lock, flags);
+
+       /* Freshen the shared index only if the split-index was written */
+       if (!ret && !new_shared_index)
+               freshen_shared_index(sha1_to_hex(si->base_sha1), 1);
+
+       return ret;
 }
 
 /*
@@ -2261,7 +2579,8 @@ int index_name_is_other(const struct index_state *istate, const char *name,
        return 1;
 }
 
-void *read_blob_data_from_index(struct index_state *istate, const char *path, unsigned long *size)
+void *read_blob_data_from_index(const struct index_state *istate,
+                               const char *path, unsigned long *size)
 {
        int pos, len;
        unsigned long sz;
@@ -2285,7 +2604,7 @@ void *read_blob_data_from_index(struct index_state *istate, const char *path, un
        }
        if (pos < 0)
                return NULL;
-       data = read_sha1_file(istate->cache[pos]->sha1, &type, &sz);
+       data = read_sha1_file(istate->cache[pos]->oid.hash, &type, &sz);
        if (!data || type != OBJ_BLOB) {
                free(data);
                return NULL;
@@ -2297,8 +2616,7 @@ void *read_blob_data_from_index(struct index_state *istate, const char *path, un
 
 void stat_validity_clear(struct stat_validity *sv)
 {
-       free(sv->sd);
-       sv->sd = NULL;
+       FREE_AND_NULL(sv->sd);
 }
 
 int stat_validity_check(struct stat_validity *sv, const char *path)
@@ -2324,3 +2642,9 @@ void stat_validity_update(struct stat_validity *sv, int fd)
                fill_stat_data(sv->sd, &st);
        }
 }
+
+void move_index_extensions(struct index_state *dst, struct index_state *src)
+{
+       dst->untracked = src->untracked;
+       src->untracked = NULL;
+}