Warn the user if we're trying to enable metadata_csum on a FS that
doesn't support extents (since block maps cannot contain checksums).
Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
---
misc/tune2fs.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/misc/tune2fs.c b/misc/tune2fs.c
index 7fee870..6feaab1 100644
--- a/misc/tune2fs.c
+++ b/misc/tune2fs.c
@@ -1113,6 +1113,14 @@ mmp_error:
if (mount_flags & EXT2_MF_MOUNTED)
fputs(_("Cannot enable metadata_csum on a mounted "
"filesystem!\n"), stderr);
+ if (!EXT2_HAS_INCOMPAT_FEATURE(fs->super,
+ EXT3_FEATURE_INCOMPAT_EXTENTS))
+ printf("%s",
+ _("Extents are not enabled. The file extent "
+ "tree can be checksummed, whereas block maps "
+ "cannot. Not enabling extents reduces the "
+ "coverage of metadata checksumming. "
+ "Re-run with -O extent to rectify.\n"));
rewrite_checksums = 1;
/* metadata_csum supersedes uninit_bg */
fs->super->s_feature_ro_compat &=
--
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