This is what I've checked in. See the comment about why we can't
ignore a difference for the extended attribute feature.
- Ted
commit a8cde73acbf6e0f9c0a3601e4f5fac2b01a27bd2
Author: Theodore Ts'o <tytso@xxxxxxx>
Date: Sat Jan 26 23:17:50 2008 -0500
Ignore "safe" flag differences when e2fsck compares superblocks
Recent e2fsprogs (1.40.3 and higher) fsck compares primary superblock to
backups, and if things differ, it forces a full check. However, the
kernel has a penchant for updating flags the first time a feature is
used - attributes, large files, etc.
This is a bad idea, and we should break the kernel of this habit,
especially for the ext4 feature flags. But for now, let's make e2fsck
avoid forcing a full check and backup except when absolutely
necessary.
Signed-off-by: Eric Sandeen <sandeen@xxxxxxxxxx>
Signed-off-by: "Theodore Ts'o" <tytso@xxxxxxx>
diff --git a/e2fsck/super.c b/e2fsck/super.c
index a4835f7..954783e 100644
--- a/e2fsck/super.c
+++ b/e2fsck/super.c
@@ -773,8 +773,26 @@ void check_super_block(e2fsck_t ctx)
/*
* Check to see if we should backup the master sb to the backup super
- * blocks.
+ * blocks. Returns non-zero if the sb should be backed up.
*/
+
+/*
+ * A few flags are set on the fly by the kernel, but only in the
+ * primary superblock. This is actually a bad thing, and we should
+ * try to discourage it in the future. In particular, for the newer
+ * ext4 files, especially EXT4_FEATURE_RO_COMPAT_DIR_NLINK and
+ * EXT3_FEATURE_INCOMPAT_EXTENTS. So some of these may go away in the
+ * future.
+ *
+ * The kernel will set EXT2_FEATURE_COMPAT_EXT_ATTR, but
+ * unfortunately, we shouldn't ignore it since if it's not set in the
+ * backup, the extended attributes in the filesystem will be stripped
+ * away.
+ */
+#define FEATURE_RO_COMPAT_IGNORE (EXT2_FEATURE_RO_COMPAT_LARGE_FILE| \
+ EXT4_FEATURE_RO_COMPAT_DIR_NLINK)
+#define FEATURE_INCOMPAT_IGNORE (EXT3_FEATURE_INCOMPAT_EXTENTS)
+
int check_backup_super_block(e2fsck_t ctx)
{
ext2_filsys fs = ctx->fs;
@@ -814,10 +832,18 @@ int check_backup_super_block(e2fsck_t ctx)
continue;
}
-#define SUPER_DIFFERENT(x) (fs->super->x != tfs->super->x)
+#define SUPER_INCOMPAT_DIFFERENT(x) \
+ (( fs->super->x & ~FEATURE_INCOMPAT_IGNORE) != \
+ (tfs->super->x & ~FEATURE_INCOMPAT_IGNORE))
+#define SUPER_RO_COMPAT_DIFFERENT(x) \
+ (( fs->super->x & ~FEATURE_RO_COMPAT_IGNORE) != \
+ (tfs->super->x & ~FEATURE_RO_COMPAT_IGNORE))
+#define SUPER_DIFFERENT(x) \
+ (fs->super->x != tfs->super->x)
+
if (SUPER_DIFFERENT(s_feature_compat) ||
- SUPER_DIFFERENT(s_feature_incompat) ||
- SUPER_DIFFERENT(s_feature_ro_compat) ||
+ SUPER_INCOMPAT_DIFFERENT(s_feature_incompat) ||
+ SUPER_RO_COMPAT_DIFFERENT(s_feature_ro_compat) ||
SUPER_DIFFERENT(s_blocks_count) ||
SUPER_DIFFERENT(s_inodes_count) ||
memcmp(fs->super->s_uuid, tfs->super->s_uuid,
-
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