svn commit: r263463 - head/sys/fs/ext2fs

[Pedro F. Giffuni]

Author: pfg
Date: Fri Mar 21 04:33:38 2014
New Revision: 263463
URL: http://svnweb.freebsd.org/changeset/base/263463

Log:
  Revert r263449;
  
  ext2fs: minor update to the dirpref policy.
  
  The change in UFS r254996, reverted the change as the
  older code seems to work better. This was not visible
  in local testing but we can trust UFS is vastly more
  exercised in diferent environments.

Modified:
  head/sys/fs/ext2fs/ext2_alloc.c

Modified: head/sys/fs/ext2fs/ext2_alloc.c
==============================================================================
--- head/sys/fs/ext2fs/ext2_alloc.c	Fri Mar 21 04:14:26 2014	(r263462)
+++ head/sys/fs/ext2fs/ext2_alloc.c	Fri Mar 21 04:33:38 2014	(r263463)
@@ -510,22 +510,6 @@ ext2_dirpref(struct inode *pip)
 	 * Limit number of dirs in one cg and reserve space for 
 	 * regular files, but only if we have no deficit in
 	 * inodes or space.
-	 *
-	 * We are trying to find a suitable cylinder group nearby
-	 * our preferred cylinder group to place a new directory.
-	 * We scan from our preferred cylinder group forward looking
-	 * for a cylinder group that meets our criterion. If we get
-	 * to the final cylinder group and do not find anything,
-	 * we start scanning backwards from our preferred cylinder
-	 * group. The ideal would be to alternate looking forward
-	 * and backward, but that is just too complex to code for
-	 * the gain it would get. The most likely place where the
-	 * backward scan would take effect is when we start near
-	 * the end of the filesystem and do not find anything from
-	 * where we are to the end. In that case, scanning backward
-	 * will likely find us a suitable cylinder group much closer
-	 * to our desired location than if we were to start scanning
-	 * forward from the beginning of the filesystem.
 	 */
 	prefcg = ino_to_cg(fs, pip->i_number);
 	for (cg = prefcg; cg < fs->e2fs_gcount; cg++)
@@ -535,7 +519,7 @@ ext2_dirpref(struct inode *pip)
 			if (fs->e2fs_contigdirs[cg] < maxcontigdirs)
 				return (cg);
 		}
-	for (cg = prefcg - 1; cg >= 0; cg--)
+	for (cg = 0; cg < prefcg; cg++)
 		if (fs->e2fs_gd[cg].ext2bgd_ndirs < maxndir &&
 		    fs->e2fs_gd[cg].ext2bgd_nifree >= minifree &&
 		    fs->e2fs_gd[cg].ext2bgd_nbfree >= minbfree) {
@@ -548,7 +532,7 @@ ext2_dirpref(struct inode *pip)
 	for (cg = prefcg; cg < fs->e2fs_gcount; cg++)
 		if (fs->e2fs_gd[cg].ext2bgd_nifree >= avgifree)
 			return (cg);
-	for (cg = prefcg - 1; cg >= 0; cg--)
+	for (cg = 0; cg < prefcg; cg++)
 		if (fs->e2fs_gd[cg].ext2bgd_nifree >= avgifree)
 			break;
 	return (cg);