diff options
| author | Mark Fasheh <mfasheh@suse.com> | 2008-12-10 17:36:25 -0800 |
|---|---|---|
| committer | Mark Fasheh <mfasheh@suse.com> | 2009-01-05 08:40:34 -0800 |
| commit | 87d35a74b15ec703910a63e0667692fb5e267be0 (patch) | |
| tree | 39f18bcf38b855fa7ec806803567532f214129f0 /fs/ocfs2/ocfs2_fs.h | |
| parent | 84008972491ca91b240f106191519781dabb8016 (diff) | |
ocfs2: Add directory block trailers.
Future ocfs2 features metaecc and indexed directories need to store a
little bit of data in each dirblock. For compatibility, we place this
in a trailer at the end of the dirblock. The trailer plays itself as an
empty dirent, so that if the features are turned off, it can be reused
without requiring a tunefs scan.
This code adds the trailer and validates it when the block is read in.
[ Mark is the original author, but I reinserted this code before his
dir index work. -- Joel ]
Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
Diffstat (limited to 'fs/ocfs2/ocfs2_fs.h')
| -rw-r--r-- | fs/ocfs2/ocfs2_fs.h | 29 |
1 files changed, 29 insertions, 0 deletions
diff --git a/fs/ocfs2/ocfs2_fs.h b/fs/ocfs2/ocfs2_fs.h index 290fa26fba6..af0013b9c17 100644 --- a/fs/ocfs2/ocfs2_fs.h +++ b/fs/ocfs2/ocfs2_fs.h @@ -65,6 +65,7 @@ #define OCFS2_EXTENT_BLOCK_SIGNATURE "EXBLK01" #define OCFS2_GROUP_DESC_SIGNATURE "GROUP01" #define OCFS2_XATTR_BLOCK_SIGNATURE "XATTR01" +#define OCFS2_DIR_TRAILER_SIGNATURE "DIRTRL1" /* Compatibility flags */ #define OCFS2_HAS_COMPAT_FEATURE(sb,mask) \ @@ -752,6 +753,34 @@ struct ocfs2_dir_entry { } __attribute__ ((packed)); /* + * Per-block record for the unindexed directory btree. This is carefully + * crafted so that the rec_len and name_len records of an ocfs2_dir_entry are + * mirrored. That way, the directory manipulation code needs a minimal amount + * of update. + * + * NOTE: Keep this structure aligned to a multiple of 4 bytes. + */ +struct ocfs2_dir_block_trailer { +/*00*/ __le64 db_compat_inode; /* Always zero. Was inode */ + + __le16 db_compat_rec_len; /* Backwards compatible with + * ocfs2_dir_entry. */ + __u8 db_compat_name_len; /* Always zero. Was name_len */ + __u8 db_reserved0; + __le16 db_reserved1; + __le16 db_free_rec_len; /* Size of largest empty hole + * in this block. (unused) */ +/*10*/ __u8 db_signature[8]; /* Signature for verification */ + __le64 db_reserved2; + __le64 db_free_next; /* Next block in list (unused) */ +/*20*/ __le64 db_blkno; /* Offset on disk, in blocks */ + __le64 db_parent_dinode; /* dinode which owns me, in + blocks */ +/*30*/ __le64 db_check; /* Error checking */ +/*40*/ +}; + +/* * On disk allocator group structure for OCFS2 */ struct ocfs2_group_desc |