Commit e4079a11 authored by Eric Sandeen's avatar Eric Sandeen Committed by Theodore Ts'o
Browse files

ext4: do not set extents feature from the kernel 



We've talked for a while about getting rid of any feature-
setting from the kernel; this gets rid of the code which would
set the INCOMPAT_EXTENTS flag on the first file write when mounted
as ext4[dev].

With this patch, if the extents feature is not already set on disk,
then mounting as ext4 will fall back to noextents with a warning,
and if -o extents is explicitly requested, the mount will fail,
also with warning.

Signed-off-by: default avatarEric Sandeen <sandeen@redhat.com>
Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
parent c07651b5

fs/ext4/ialloc.c

+1 −5
Original line number Diff line number Diff line
@@ -836,14 +836,10 @@ got: 
		goto fail_free_drop;



	if (test_opt(sb, EXTENTS)) {

		/* set extent flag only for diretory, file and normal symlink*/

		/* set extent flag only for directory, file and normal symlink*/

		if (S_ISDIR(mode) || S_ISREG(mode) || S_ISLNK(mode)) {

			EXT4_I(inode)->i_flags |= EXT4_EXTENTS_FL;

			ext4_ext_tree_init(handle, inode);

			err = ext4_update_incompat_feature(handle, sb,

					EXT4_FEATURE_INCOMPAT_EXTENTS);

			if (err)

				goto fail_free_drop;

		}

	}

fs/ext4/super.c

+17 −4
Original line number Diff line number Diff line
@@ -1324,6 +1324,13 @@ set_qf_format: 
			clear_opt(sbi->s_mount_opt, NOBH);

			break;

		case Opt_extents:

			if (!EXT4_HAS_INCOMPAT_FEATURE(sb,

					EXT4_FEATURE_INCOMPAT_EXTENTS)) {

				ext4_warning(sb, __func__,

					"extents feature not enabled "

					"on this filesystem, use tune2fs\n");

				return 0;

			}

			set_opt (sbi->s_mount_opt, EXTENTS);

			break;

		case Opt_noextents:
@@ -1997,12 +2004,18 @@ static int ext4_fill_super (struct super_block *sb, void *data, int silent) 


	/*

	 * turn on extents feature by default in ext4 filesystem

	 * User -o noextents to turn it off

	 * only if feature flag already set by mkfs or tune2fs.

	 * Use -o noextents to turn it off

	 */

	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS))

		set_opt(sbi->s_mount_opt, EXTENTS);

	else

		ext4_warning(sb, __func__,

			"extents feature not enabled on this filesystem, "

			"use tune2fs.\n");

	/*

	 * turn on mballoc feature by default in ext4 filesystem

	 * User -o nomballoc to turn it off

	 * turn on mballoc code by default in ext4 filesystem

	 * Use -o nomballoc to turn it off

	 */

	set_opt(sbi->s_mount_opt, MBALLOC);

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