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| author | Theodore Ts'o <tytso@mit.edu> | 2008-01-26 23:17:50 -0500 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2008-01-26 23:17:50 -0500 |
| commit | a8cde73acbf6e0f9c0a3601e4f5fac2b01a27bd2 (patch) | |
| tree | 615cca32ed7a471d34b4666087470fcc3f3d2af0 | |
| parent | 2921332fd88b843ffb828d9c18f05bfd171ace76 (diff) | |
| download | e2fsprogs-a8cde73acbf6e0f9c0a3601e4f5fac2b01a27bd2.tar.gz | |
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@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
| -rw-r--r-- | e2fsck/super.c | 34 |
1 files changed, 30 insertions, 4 deletions
diff --git a/e2fsck/super.c b/e2fsck/super.c index a4835f76..954783e0 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, |