Author: pfg
Date: Sat Feb 22 22:07:16 2014
New Revision: 262346
URL: http://svnweb.freebsd.org/changeset/base/262346
Log:
ext2fs: fully enable ext4 read-only support.
The ext4 developers tend to tag Ext4-specific flags as
"incompatible" even when such features are not relevant for
read-only support. This is a consequence of the process
though which this filesystem is implemented without design
and the fact that some new features are not extensible to
ext2/3.
Organize the features according to what we support and sort
them so that we can now read-only mount filesystems with
some features that may be found in newly formatted ext4 fs.
Submitted by: Zheng Liu
Reviewed by: pfg
MFC after: 5 days
Modified:
head/sys/fs/ext2fs/ext2_vfsops.c
head/sys/fs/ext2fs/ext2fs.h
Modified: head/sys/fs/ext2fs/ext2_vfsops.c
==============================================================================
--- head/sys/fs/ext2fs/ext2_vfsops.c Sat Feb 22 22:03:26 2014
(r262345)
+++ head/sys/fs/ext2fs/ext2_vfsops.c Sat Feb 22 22:07:16 2014
(r262346)
@@ -290,7 +290,8 @@ ext2_check_sb_compat(struct ext2fs *es,
return (1);
}
if (es->e2fs_rev > E2FS_REV0) {
- if (es->e2fs_features_incompat & ~EXT2F_INCOMPAT_SUPP) {
+ if (es->e2fs_features_incompat & ~(EXT2F_INCOMPAT_SUPP |
+ EXT4F_RO_INCOMPAT_SUPP)) {
printf(
"WARNING: mount of %s denied due to unsupported optional features\n",
devtoname(dev));
Modified: head/sys/fs/ext2fs/ext2fs.h
==============================================================================
--- head/sys/fs/ext2fs/ext2fs.h Sat Feb 22 22:03:26 2014 (r262345)
+++ head/sys/fs/ext2fs/ext2fs.h Sat Feb 22 22:07:16 2014 (r262346)
@@ -200,19 +200,26 @@ struct csum {
* We support the following REV1 features:
* - EXT2F_ROCOMPAT_SPARSESUPER
* - EXT2F_ROCOMPAT_LARGEFILE
+ * - EXT2F_ROCOMPAT_EXTRA_ISIZE
* - EXT2F_INCOMPAT_FTYPE
*
* We partially (read-only) support the following EXT4 features:
* - EXT2F_ROCOMPAT_HUGE_FILE
- * - EXT2F_ROCOMPAT_EXTRA_ISIZE
* - EXT2F_INCOMPAT_EXTENTS
+ *
+ * We do not support these EXT4 features but they are irrelevant
+ * for read-only support:
+ * - EXT2F_INCOMPAT_FLEX_BG
+ * - EXT2F_INCOMPAT_META_BG
*/
-#define EXT2F_COMPAT_SUPP 0x0000
+#define EXT2F_COMPAT_SUPP EXT2F_COMPAT_DIRHASHINDEX
#define EXT2F_ROCOMPAT_SUPP (EXT2F_ROCOMPAT_SPARSESUPER | \
EXT2F_ROCOMPAT_LARGEFILE | \
EXT2F_ROCOMPAT_EXTRA_ISIZE)
-#define EXT2F_INCOMPAT_SUPP (EXT2F_INCOMPAT_FTYPE | \
- EXT2F_INCOMPAT_EXTENTS)
+#define EXT2F_INCOMPAT_SUPP EXT2F_INCOMPAT_FTYPE
+#define EXT4F_RO_INCOMPAT_SUPP (EXT2F_INCOMPAT_EXTENTS | \
+ EXT2F_INCOMPAT_FLEX_BG | \
+ EXT2F_INCOMPAT_META_BG )
/* Assume that user mode programs are passing in an ext2fs superblock, not
* a kernel struct super_block. This will allow us to call the feature-test
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