allow renaming bootstrap, and change the name of bootstrap.conf accordingly

[gnulib.git] / lib / fts.c

diff --git a/lib/fts.c b/lib/fts.c
index 3cf49fa..d4f7db2 100644 (file)
--- a/lib/fts.c
+++ b/lib/fts.c
@@ -934,43 +934,49 @@ fts_children (register FTS *sp, int instr)
        return (sp->fts_child);
 }
 
-#if defined HAVE_SYS_VFS_H && HAVE_FSTATFS && HAVE_STRUCT_STATFS_F_TYPE
-# include <sys/statfs.h>
-/* FIXME: what about when f_type is not an integral type?
-   deal with that if/when it's encountered.  */
+#if defined __linux__ \
+  && HAVE_SYS_VFS_H && HAVE_FSTATFS && HAVE_STRUCT_STATFS_F_TYPE
+
+#include <sys/vfs.h>
+
+/* Linux-specific constants from coreutils' src/fs.h */
+# define S_MAGIC_TMPFS 0x1021994
+# define S_MAGIC_NFS 0x6969
+
+/* Return false if it is easy to determine the file system type of
+   the directory on which DIR_FD is open, and sorting dirents on
+   inode numbers is known not to improve traversal performance with
+   that type of file system.  Otherwise, return true.  */
 static bool
-fs_handles_readdir_ordered_dirents_efficiently (uintmax_t fs_type)
+dirent_inode_sort_may_be_useful (int dir_fd)
 {
-/* From coreutils' src/fs.h */
-#define S_MAGIC_TMPFS 0x1021994
-#define S_MAGIC_NFS 0x6969
-  switch (fs_type)
+  /* Skip the sort only if we can determine efficiently
+     that skipping it is the right thing to do.
+     The cost of performing an unnecessary sort is negligible,
+     while the cost of *not* performing it can be O(N^2) with
+     a very large constant.  */
+  struct statfs fs_buf;
+
+  /* If fstatfs fails, assume sorting would be useful.  */
+  if (fstatfs (dir_fd, &fs_buf) != 0)
+    return true;
+
+  /* FIXME: what about when f_type is not an integral type?
+     deal with that if/when it's encountered.  */
+  switch (fs_buf.f_type)
     {
     case S_MAGIC_TMPFS:
     case S_MAGIC_NFS:
-      return true;
-    default:
+      /* On a file system of any of these types, sorting
+        is unnecessary, and hence wasteful.  */
       return false;
-    }
-}
 
-/* Return true if it is easy to determine the file system type of the
-   current directory, and sorting dirents on inode numbers is known to
-   improve traversal performance with that type of file system.  */
-static bool
-dirent_inode_sort_may_be_useful (FTS const *sp)
-{
-  struct statfs fs_buf;
-  /* Skip the sort only if we can determine efficiently
-     that it's the right thing to do.  */
-  bool skip = (ISSET (FTS_CWDFD)
-              && fstatfs (sp->fts_cwd_fd, &fs_buf) == 0
-              && fs_handles_readdir_ordered_dirents_efficiently
-                   (fs_buf.f_type));
-  return !skip;
+    default:
+      return true;
+    }
 }
 #else
-static bool dirent_inode_sort_may_be_useful (FTS const *sp) { return true; }
+static bool dirent_inode_sort_may_be_useful (int dir_fd) { return true; }
 #endif
 
 /* A comparison function to sort on increasing inode number.
@@ -981,8 +987,8 @@ static bool dirent_inode_sort_may_be_useful (FTS const *sp) { return true; }
 static int
 fts_compare_ino (struct _ftsent const **a, struct _ftsent const **b)
 {
-  return (a[0]->fts_statp->st_ino < b[0]->fts_statp->st_ino ? 1
-         : b[0]->fts_statp->st_ino < a[0]->fts_statp->st_ino ? -1 : 0);
+  return (a[0]->fts_statp->st_ino < b[0]->fts_statp->st_ino ? -1
+         : b[0]->fts_statp->st_ino < a[0]->fts_statp->st_ino ? 1 : 0);
 }
 
 /*
@@ -1289,7 +1295,8 @@ mem1:                             saved_errno = errno;
           inode numbers.  */
        if (nitems > _FTS_INODE_SORT_DIR_ENTRIES_THRESHOLD
            && !sp->fts_compar
-           && dirent_inode_sort_may_be_useful (sp)) {
+           && ISSET (FTS_CWDFD)
+           && dirent_inode_sort_may_be_useful (sp->fts_cwd_fd)) {
                sp->fts_compar = fts_compare_ino;
                head = fts_sort (sp, head, nitems);
                sp->fts_compar = NULL;