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Commit 87d35a74 authored by Mark Fasheh's avatar Mark Fasheh
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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: default avatarJoel Becker <joel.becker@oracle.com>
Signed-off-by: default avatarMark Fasheh <mfasheh@suse.com>
parent 84008972
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+183 −14
Original line number Diff line number Diff line
@@ -83,6 +83,63 @@ static int ocfs2_do_extend_dir(struct super_block *sb,
			       struct ocfs2_alloc_context *meta_ac,
			       struct buffer_head **new_bh);

/*
 * These are distinct checks because future versions of the file system will
 * want to have a trailing dirent structure independent of indexing.
 */
static int ocfs2_dir_has_trailer(struct inode *dir)
{
	if (OCFS2_I(dir)->ip_dyn_features & OCFS2_INLINE_DATA_FL)
		return 0;

	return ocfs2_meta_ecc(OCFS2_SB(dir->i_sb));
}

static int ocfs2_supports_dir_trailer(struct ocfs2_super *osb)
{
	return ocfs2_meta_ecc(osb);
}

static inline unsigned int ocfs2_dir_trailer_blk_off(struct super_block *sb)
{
	return sb->s_blocksize - sizeof(struct ocfs2_dir_block_trailer);
}

#define ocfs2_trailer_from_bh(_bh, _sb) ((struct ocfs2_dir_block_trailer *) ((_bh)->b_data + ocfs2_dir_trailer_blk_off((_sb))))

/*
 * XXX: This is executed once on every dirent. We should consider optimizing
 * it.
 */
static int ocfs2_skip_dir_trailer(struct inode *dir,
				  struct ocfs2_dir_entry *de,
				  unsigned long offset,
				  unsigned long blklen)
{
	unsigned long toff = blklen - sizeof(struct ocfs2_dir_block_trailer);

	if (!ocfs2_dir_has_trailer(dir))
		return 0;

	if (offset != toff)
		return 0;

	return 1;
}

static void ocfs2_init_dir_trailer(struct inode *inode,
				   struct buffer_head *bh)
{
	struct ocfs2_dir_block_trailer *trailer;

	trailer = ocfs2_trailer_from_bh(bh, inode->i_sb);
	strcpy(trailer->db_signature, OCFS2_DIR_TRAILER_SIGNATURE);
	trailer->db_compat_rec_len =
			cpu_to_le16(sizeof(struct ocfs2_dir_block_trailer));
	trailer->db_parent_dinode = cpu_to_le64(OCFS2_I(inode)->ip_blkno);
	trailer->db_blkno = cpu_to_le64(bh->b_blocknr);
}

/*
 * bh passed here can be an inode block or a dir data block, depending
 * on the inode inline data flag.
@@ -232,16 +289,60 @@ static int ocfs2_read_dir_block(struct inode *inode, u64 v_block,
{
	int rc = 0;
	struct buffer_head *tmp = *bh;
	struct ocfs2_dir_block_trailer *trailer;

	rc = ocfs2_read_virt_blocks(inode, v_block, 1, &tmp, flags,
				    ocfs2_validate_dir_block);
	if (rc)
	if (rc) {
		mlog_errno(rc);
		goto out;
	}

	/*
	 * We check the trailer here rather than in
	 * ocfs2_validate_dir_block() because that function doesn't have
	 * the inode to test.
	 */
	if (!(flags & OCFS2_BH_READAHEAD) &&
	    ocfs2_dir_has_trailer(inode)) {
		trailer = ocfs2_trailer_from_bh(tmp, inode->i_sb);
		if (!OCFS2_IS_VALID_DIR_TRAILER(trailer)) {
			rc = -EINVAL;
			ocfs2_error(inode->i_sb,
				    "Invalid dirblock #%llu: "
				    "signature = %.*s\n",
				    (unsigned long long)tmp->b_blocknr, 7,
				    trailer->db_signature);
			goto out;
		}
		if (le64_to_cpu(trailer->db_blkno) != tmp->b_blocknr) {
			rc = -EINVAL;
			ocfs2_error(inode->i_sb,
				    "Directory block #%llu has an invalid "
				    "db_blkno of %llu",
				    (unsigned long long)tmp->b_blocknr,
				    (unsigned long long)le64_to_cpu(trailer->db_blkno));
			goto out;
		}
		if (le64_to_cpu(trailer->db_parent_dinode) !=
		    OCFS2_I(inode)->ip_blkno) {
			rc = -EINVAL;
			ocfs2_error(inode->i_sb,
				    "Directory block #%llu on dinode "
				    "#%llu has an invalid parent_dinode "
				    "of %llu",
				    (unsigned long long)tmp->b_blocknr,
				    (unsigned long long)OCFS2_I(inode)->ip_blkno,
				    (unsigned long long)le64_to_cpu(trailer->db_blkno));
			goto out;
		}
	}

	/* If ocfs2_read_virt_blocks() got us a new bh, pass it up. */
	if (!rc && !*bh)
	if (!*bh)
		*bh = tmp;

out:
	return rc ? -EIO : 0;
}

@@ -581,6 +682,16 @@ int __ocfs2_add_entry(handle_t *handle,
			goto bail;
		}

		/* We're guaranteed that we should have space, so we
		 * can't possibly have hit the trailer...right? */
		mlog_bug_on_msg(ocfs2_skip_dir_trailer(dir, de, offset, size),
				"Hit dir trailer trying to insert %.*s "
			        "(namelen %d) into directory %llu.  "
				"offset is %lu, trailer offset is %d\n",
				namelen, name, namelen,
				(unsigned long long)parent_fe_bh->b_blocknr,
				offset, ocfs2_dir_trailer_blk_off(dir->i_sb));

		if (ocfs2_dirent_would_fit(de, rec_len)) {
			dir->i_mtime = dir->i_ctime = CURRENT_TIME;
			retval = ocfs2_mark_inode_dirty(handle, dir, parent_fe_bh);
@@ -622,6 +733,7 @@ int __ocfs2_add_entry(handle_t *handle,
			retval = 0;
			goto bail;
		}

		offset += le16_to_cpu(de->rec_len);
		de = (struct ocfs2_dir_entry *) ((char *) de + le16_to_cpu(de->rec_len));
	}
@@ -1059,9 +1171,15 @@ int ocfs2_empty_dir(struct inode *inode)
	return !priv.seen_other;
}

static void ocfs2_fill_initial_dirents(struct inode *inode,
/*
 * Fills "." and ".." dirents in a new directory block. Returns dirent for
 * "..", which might be used during creation of a directory with a trailing
 * header. It is otherwise safe to ignore the return code.
 */
static struct ocfs2_dir_entry *ocfs2_fill_initial_dirents(struct inode *inode,
							  struct inode *parent,
				       char *start, unsigned int size)
							  char *start,
							  unsigned int size)
{
	struct ocfs2_dir_entry *de = (struct ocfs2_dir_entry *)start;

@@ -1078,6 +1196,8 @@ static void ocfs2_fill_initial_dirents(struct inode *inode,
	de->name_len = 2;
	strcpy(de->name, "..");
	ocfs2_set_de_type(de, S_IFDIR);

	return de;
}

/*
@@ -1130,10 +1250,15 @@ static int ocfs2_fill_new_dir_el(struct ocfs2_super *osb,
				 struct ocfs2_alloc_context *data_ac)
{
	int status;
	unsigned int size = osb->sb->s_blocksize;
	struct buffer_head *new_bh = NULL;
	struct ocfs2_dir_entry *de;

	mlog_entry_void();

	if (ocfs2_supports_dir_trailer(osb))
		size = ocfs2_dir_trailer_blk_off(parent->i_sb);

	status = ocfs2_do_extend_dir(osb->sb, handle, inode, fe_bh,
				     data_ac, NULL, &new_bh);
	if (status < 0) {
@@ -1151,8 +1276,9 @@ static int ocfs2_fill_new_dir_el(struct ocfs2_super *osb,
	}
	memset(new_bh->b_data, 0, osb->sb->s_blocksize);

	ocfs2_fill_initial_dirents(inode, parent, new_bh->b_data,
				   osb->sb->s_blocksize);
	de = ocfs2_fill_initial_dirents(inode, parent, new_bh->b_data, size);
	if (ocfs2_supports_dir_trailer(osb))
		ocfs2_init_dir_trailer(inode, new_bh);

	status = ocfs2_journal_dirty(handle, new_bh);
	if (status < 0) {
@@ -1193,13 +1319,27 @@ int ocfs2_fill_new_dir(struct ocfs2_super *osb,
				     data_ac);
}

/*
 * Expand rec_len of the rightmost dirent in a directory block so that it
 * contains the end of our valid space for dirents. We do this during
 * expansion from an inline directory to one with extents. The first dir block
 * in that case is taken from the inline data portion of the inode block.
 *
 * We add the dir trailer if this filesystem wants it.
 */
static void ocfs2_expand_last_dirent(char *start, unsigned int old_size,
				     unsigned int new_size)
				     struct super_block *sb)
{
	struct ocfs2_dir_entry *de;
	struct ocfs2_dir_entry *prev_de;
	char *de_buf, *limit;
	unsigned int bytes = new_size - old_size;
	unsigned int new_size = sb->s_blocksize;
	unsigned int bytes;

	if (ocfs2_supports_dir_trailer(OCFS2_SB(sb)))
		new_size = ocfs2_dir_trailer_blk_off(sb);

	bytes = new_size - old_size;

	limit = start + old_size;
	de_buf = start;
@@ -1316,8 +1456,9 @@ static int ocfs2_expand_inline_dir(struct inode *dir, struct buffer_head *di_bh,
	memcpy(dirdata_bh->b_data, di->id2.i_data.id_data, i_size_read(dir));
	memset(dirdata_bh->b_data + i_size_read(dir), 0,
	       sb->s_blocksize - i_size_read(dir));
	ocfs2_expand_last_dirent(dirdata_bh->b_data, i_size_read(dir),
				 sb->s_blocksize);
	ocfs2_expand_last_dirent(dirdata_bh->b_data, i_size_read(dir), sb);
	if (ocfs2_supports_dir_trailer(osb))
		ocfs2_init_dir_trailer(dir, dirdata_bh);

	ret = ocfs2_journal_dirty(handle, dirdata_bh);
	if (ret) {
@@ -1604,9 +1745,15 @@ static int ocfs2_extend_dir(struct ocfs2_super *osb,
		goto bail;
	}
	memset(new_bh->b_data, 0, sb->s_blocksize);

	de = (struct ocfs2_dir_entry *) new_bh->b_data;
	de->inode = 0;
	if (ocfs2_dir_has_trailer(dir)) {
		de->rec_len = cpu_to_le16(ocfs2_dir_trailer_blk_off(sb));
		ocfs2_init_dir_trailer(dir, new_bh);
	} else {
		de->rec_len = cpu_to_le16(sb->s_blocksize);
	}
	status = ocfs2_journal_dirty(handle, new_bh);
	if (status < 0) {
		mlog_errno(status);
@@ -1648,11 +1795,21 @@ static int ocfs2_find_dir_space_id(struct inode *dir, struct buffer_head *di_bh,
				   unsigned int *blocks_wanted)
{
	int ret;
	struct super_block *sb = dir->i_sb;
	struct ocfs2_dinode *di = (struct ocfs2_dinode *)di_bh->b_data;
	struct ocfs2_dir_entry *de, *last_de = NULL;
	char *de_buf, *limit;
	unsigned long offset = 0;
	unsigned int rec_len, new_rec_len;
	unsigned int rec_len, new_rec_len, free_space = dir->i_sb->s_blocksize;

	/*
	 * This calculates how many free bytes we'd have in block zero, should
	 * this function force expansion to an extent tree.
	 */
	if (ocfs2_supports_dir_trailer(OCFS2_SB(sb)))
		free_space = ocfs2_dir_trailer_blk_off(sb) - i_size_read(dir);
	else
		free_space = dir->i_sb->s_blocksize - i_size_read(dir);

	de_buf = di->id2.i_data.id_data;
	limit = de_buf + i_size_read(dir);
@@ -1669,6 +1826,11 @@ static int ocfs2_find_dir_space_id(struct inode *dir, struct buffer_head *di_bh,
			ret = -EEXIST;
			goto out;
		}
		/*
		 * No need to check for a trailing dirent record here as
		 * they're not used for inline dirs.
		 */

		if (ocfs2_dirent_would_fit(de, rec_len)) {
			/* Ok, we found a spot. Return this bh and let
			 * the caller actually fill it in. */
@@ -1689,7 +1851,7 @@ static int ocfs2_find_dir_space_id(struct inode *dir, struct buffer_head *di_bh,
	 * dirent can be found.
	 */
	*blocks_wanted = 1;
	new_rec_len = le16_to_cpu(last_de->rec_len) + (dir->i_sb->s_blocksize - i_size_read(dir));
	new_rec_len = le16_to_cpu(last_de->rec_len) + free_space;
	if (new_rec_len < (rec_len + OCFS2_DIR_REC_LEN(last_de->name_len)))
		*blocks_wanted = 2;

@@ -1707,6 +1869,7 @@ static int ocfs2_find_dir_space_el(struct inode *dir, const char *name,
	struct ocfs2_dir_entry *de;
	struct super_block *sb = dir->i_sb;
	int status;
	int blocksize = dir->i_sb->s_blocksize;

	status = ocfs2_read_dir_block(dir, 0, &bh, 0);
	if (status) {
@@ -1748,6 +1911,11 @@ static int ocfs2_find_dir_space_el(struct inode *dir, const char *name,
			status = -EEXIST;
			goto bail;
		}

		if (ocfs2_skip_dir_trailer(dir, de, offset % blocksize,
					   blocksize))
			goto next;

		if (ocfs2_dirent_would_fit(de, rec_len)) {
			/* Ok, we found a spot. Return this bh and let
			 * the caller actually fill it in. */
@@ -1756,6 +1924,7 @@ static int ocfs2_find_dir_space_el(struct inode *dir, const char *name,
			status = 0;
			goto bail;
		}
next:
		offset += le16_to_cpu(de->rec_len);
		de = (struct ocfs2_dir_entry *)((char *) de + le16_to_cpu(de->rec_len));
	}
+3 −0
Original line number Diff line number Diff line
@@ -470,6 +470,9 @@ static inline int ocfs2_uses_extended_slot_map(struct ocfs2_super *osb)
#define OCFS2_IS_VALID_XATTR_BLOCK(ptr)					\
	(!strcmp((ptr)->xb_signature, OCFS2_XATTR_BLOCK_SIGNATURE))

#define OCFS2_IS_VALID_DIR_TRAILER(ptr)					\
	(!strcmp((ptr)->db_signature, OCFS2_DIR_TRAILER_SIGNATURE))

static inline unsigned long ino_from_blkno(struct super_block *sb,
					   u64 blkno)
{
+29 −0
Original line number Diff line number Diff line
@@ -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)			\
@@ -751,6 +752,34 @@ struct ocfs2_dir_entry {
/* Actual on-disk length specified by rec_len */
} __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
 */