xfs_dir2_block.c

linux 内核源代码

	int			ent;		/* leaf entry index */
	int			error;		/* error return value */
	xfs_mount_t		*mp;		/* filesystem mount point */

	xfs_dir2_trace_args("block_replace", args);
	/*
	 * Lookup the entry in the directory.  Get buffer and entry index.
	 * This will always succeed since the caller has already done a lookup.
	 */
	if ((error = xfs_dir2_block_lookup_int(args, &bp, &ent))) {
		return error;
	}
	dp = args->dp;
	mp = dp->i_mount;
	block = bp->data;
	btp = xfs_dir2_block_tail_p(mp, block);
	blp = xfs_dir2_block_leaf_p(btp);
	/*
	 * Point to the data entry we need to change.
	 */
	dep = (xfs_dir2_data_entry_t *)
	      ((char *)block + xfs_dir2_dataptr_to_off(mp, be32_to_cpu(blp[ent].address)));
	ASSERT(be64_to_cpu(dep->inumber) != args->inumber);
	/*
	 * Change the inode number to the new value.
	 */
	dep->inumber = cpu_to_be64(args->inumber);
	xfs_dir2_data_log_entry(args->trans, bp, dep);
	xfs_dir2_data_check(dp, bp);
	xfs_da_buf_done(bp);
	return 0;
}

/*
 * Qsort comparison routine for the block leaf entries.
 */
static int					/* sort order */
xfs_dir2_block_sort(
	const void			*a,	/* first leaf entry */
	const void			*b)	/* second leaf entry */
{
	const xfs_dir2_leaf_entry_t	*la;	/* first leaf entry */
	const xfs_dir2_leaf_entry_t	*lb;	/* second leaf entry */

	la = a;
	lb = b;
	return be32_to_cpu(la->hashval) < be32_to_cpu(lb->hashval) ? -1 :
		(be32_to_cpu(la->hashval) > be32_to_cpu(lb->hashval) ? 1 : 0);
}

/*
 * Convert a V2 leaf directory to a V2 block directory if possible.
 */
int						/* error */
xfs_dir2_leaf_to_block(
	xfs_da_args_t		*args,		/* operation arguments */
	xfs_dabuf_t		*lbp,		/* leaf buffer */
	xfs_dabuf_t		*dbp)		/* data buffer */
{
	__be16			*bestsp;	/* leaf bests table */
	xfs_dir2_block_t	*block;		/* block structure */
	xfs_dir2_block_tail_t	*btp;		/* block tail */
	xfs_inode_t		*dp;		/* incore directory inode */
	xfs_dir2_data_unused_t	*dup;		/* unused data entry */
	int			error;		/* error return value */
	int			from;		/* leaf from index */
	xfs_dir2_leaf_t		*leaf;		/* leaf structure */
	xfs_dir2_leaf_entry_t	*lep;		/* leaf entry */
	xfs_dir2_leaf_tail_t	*ltp;		/* leaf tail structure */
	xfs_mount_t		*mp;		/* file system mount point */
	int			needlog;	/* need to log data header */
	int			needscan;	/* need to scan for bestfree */
	xfs_dir2_sf_hdr_t	sfh;		/* shortform header */
	int			size;		/* bytes used */
	__be16			*tagp;		/* end of entry (tag) */
	int			to;		/* block/leaf to index */
	xfs_trans_t		*tp;		/* transaction pointer */

	xfs_dir2_trace_args_bb("leaf_to_block", args, lbp, dbp);
	dp = args->dp;
	tp = args->trans;
	mp = dp->i_mount;
	leaf = lbp->data;
	ASSERT(be16_to_cpu(leaf->hdr.info.magic) == XFS_DIR2_LEAF1_MAGIC);
	ltp = xfs_dir2_leaf_tail_p(mp, leaf);
	/*
	 * If there are data blocks other than the first one, take this
	 * opportunity to remove trailing empty data blocks that may have
	 * been left behind during no-space-reservation operations.
	 * These will show up in the leaf bests table.
	 */
	while (dp->i_d.di_size > mp->m_dirblksize) {
		bestsp = xfs_dir2_leaf_bests_p(ltp);
		if (be16_to_cpu(bestsp[be32_to_cpu(ltp->bestcount) - 1]) ==
		    mp->m_dirblksize - (uint)sizeof(block->hdr)) {
			if ((error =
			    xfs_dir2_leaf_trim_data(args, lbp,
				    (xfs_dir2_db_t)(be32_to_cpu(ltp->bestcount) - 1))))
				goto out;
		} else {
			error = 0;
			goto out;
		}
	}
	/*
	 * Read the data block if we don't already have it, give up if it fails.
	 */
	if (dbp == NULL &&
	    (error = xfs_da_read_buf(tp, dp, mp->m_dirdatablk, -1, &dbp,
		    XFS_DATA_FORK))) {
		goto out;
	}
	block = dbp->data;
	ASSERT(be32_to_cpu(block->hdr.magic) == XFS_DIR2_DATA_MAGIC);
	/*
	 * Size of the "leaf" area in the block.
	 */
	size = (uint)sizeof(block->tail) +
	       (uint)sizeof(*lep) * (be16_to_cpu(leaf->hdr.count) - be16_to_cpu(leaf->hdr.stale));
	/*
	 * Look at the last data entry.
	 */
	tagp = (__be16 *)((char *)block + mp->m_dirblksize) - 1;
	dup = (xfs_dir2_data_unused_t *)((char *)block + be16_to_cpu(*tagp));
	/*
	 * If it's not free or is too short we can't do it.
	 */
	if (be16_to_cpu(dup->freetag) != XFS_DIR2_DATA_FREE_TAG ||
	    be16_to_cpu(dup->length) < size) {
		error = 0;
		goto out;
	}
	/*
	 * Start converting it to block form.
	 */
	block->hdr.magic = cpu_to_be32(XFS_DIR2_BLOCK_MAGIC);
	needlog = 1;
	needscan = 0;
	/*
	 * Use up the space at the end of the block (blp/btp).
	 */
	xfs_dir2_data_use_free(tp, dbp, dup, mp->m_dirblksize - size, size,
		&needlog, &needscan);
	/*
	 * Initialize the block tail.
	 */
	btp = xfs_dir2_block_tail_p(mp, block);
	btp->count = cpu_to_be32(be16_to_cpu(leaf->hdr.count) - be16_to_cpu(leaf->hdr.stale));
	btp->stale = 0;
	xfs_dir2_block_log_tail(tp, dbp);
	/*
	 * Initialize the block leaf area.  We compact out stale entries.
	 */
	lep = xfs_dir2_block_leaf_p(btp);
	for (from = to = 0; from < be16_to_cpu(leaf->hdr.count); from++) {
		if (be32_to_cpu(leaf->ents[from].address) == XFS_DIR2_NULL_DATAPTR)
			continue;
		lep[to++] = leaf->ents[from];
	}
	ASSERT(to == be32_to_cpu(btp->count));
	xfs_dir2_block_log_leaf(tp, dbp, 0, be32_to_cpu(btp->count) - 1);
	/*
	 * Scan the bestfree if we need it and log the data block header.
	 */
	if (needscan)
		xfs_dir2_data_freescan(mp, (xfs_dir2_data_t *)block, &needlog);
	if (needlog)
		xfs_dir2_data_log_header(tp, dbp);
	/*
	 * Pitch the old leaf block.
	 */
	error = xfs_da_shrink_inode(args, mp->m_dirleafblk, lbp);
	lbp = NULL;
	if (error) {
		goto out;
	}
	/*
	 * Now see if the resulting block can be shrunken to shortform.
	 */
	if ((size = xfs_dir2_block_sfsize(dp, block, &sfh)) >
	    XFS_IFORK_DSIZE(dp)) {
		error = 0;
		goto out;
	}
	return xfs_dir2_block_to_sf(args, dbp, size, &sfh);
out:
	if (lbp)
		xfs_da_buf_done(lbp);
	if (dbp)
		xfs_da_buf_done(dbp);
	return error;
}

/*
 * Convert the shortform directory to block form.
 */
int						/* error */
xfs_dir2_sf_to_block(
	xfs_da_args_t		*args)		/* operation arguments */
{
	xfs_dir2_db_t		blkno;		/* dir-relative block # (0) */
	xfs_dir2_block_t	*block;		/* block structure */
	xfs_dir2_leaf_entry_t	*blp;		/* block leaf entries */
	xfs_dabuf_t		*bp;		/* block buffer */
	xfs_dir2_block_tail_t	*btp;		/* block tail pointer */
	char			*buf;		/* sf buffer */
	int			buf_len;
	xfs_dir2_data_entry_t	*dep;		/* data entry pointer */
	xfs_inode_t		*dp;		/* incore directory inode */
	int			dummy;		/* trash */
	xfs_dir2_data_unused_t	*dup;		/* unused entry pointer */
	int			endoffset;	/* end of data objects */
	int			error;		/* error return value */
	int			i;		/* index */
	xfs_mount_t		*mp;		/* filesystem mount point */
	int			needlog;	/* need to log block header */
	int			needscan;	/* need to scan block freespc */
	int			newoffset;	/* offset from current entry */
	int			offset;		/* target block offset */
	xfs_dir2_sf_entry_t	*sfep;		/* sf entry pointer */
	xfs_dir2_sf_t		*sfp;		/* shortform structure */
	__be16			*tagp;		/* end of data entry */
	xfs_trans_t		*tp;		/* transaction pointer */

	xfs_dir2_trace_args("sf_to_block", args);
	dp = args->dp;
	tp = args->trans;
	mp = dp->i_mount;
	ASSERT(dp->i_df.if_flags & XFS_IFINLINE);
	/*
	 * Bomb out if the shortform directory is way too short.
	 */
	if (dp->i_d.di_size < offsetof(xfs_dir2_sf_hdr_t, parent)) {
		ASSERT(XFS_FORCED_SHUTDOWN(mp));
		return XFS_ERROR(EIO);
	}
	ASSERT(dp->i_df.if_bytes == dp->i_d.di_size);
	ASSERT(dp->i_df.if_u1.if_data != NULL);
	sfp = (xfs_dir2_sf_t *)dp->i_df.if_u1.if_data;
	ASSERT(dp->i_d.di_size >= xfs_dir2_sf_hdr_size(sfp->hdr.i8count));
	/*
	 * Copy the directory into the stack buffer.
	 * Then pitch the incore inode data so we can make extents.
	 */

	buf_len = dp->i_df.if_bytes;
	buf = kmem_alloc(dp->i_df.if_bytes, KM_SLEEP);

	memcpy(buf, sfp, dp->i_df.if_bytes);
	xfs_idata_realloc(dp, -dp->i_df.if_bytes, XFS_DATA_FORK);
	dp->i_d.di_size = 0;
	xfs_trans_log_inode(tp, dp, XFS_ILOG_CORE);
	/*
	 * Reset pointer - old sfp is gone.
	 */
	sfp = (xfs_dir2_sf_t *)buf;
	/*
	 * Add block 0 to the inode.
	 */
	error = xfs_dir2_grow_inode(args, XFS_DIR2_DATA_SPACE, &blkno);
	if (error) {
		kmem_free(buf, buf_len);
		return error;
	}
	/*
	 * Initialize the data block.
	 */
	error = xfs_dir2_data_init(args, blkno, &bp);
	if (error) {
		kmem_free(buf, buf_len);
		return error;
	}
	block = bp->data;
	block->hdr.magic = cpu_to_be32(XFS_DIR2_BLOCK_MAGIC);
	/*
	 * Compute size of block "tail" area.
	 */
	i = (uint)sizeof(*btp) +
	    (sfp->hdr.count + 2) * (uint)sizeof(xfs_dir2_leaf_entry_t);
	/*
	 * The whole thing is initialized to free by the init routine.
	 * Say we're using the leaf and tail area.
	 */
	dup = (xfs_dir2_data_unused_t *)block->u;
	needlog = needscan = 0;
	xfs_dir2_data_use_free(tp, bp, dup, mp->m_dirblksize - i, i, &needlog,
		&needscan);
	ASSERT(needscan == 0);
	/*
	 * Fill in the tail.
	 */
	btp = xfs_dir2_block_tail_p(mp, block);
	btp->count = cpu_to_be32(sfp->hdr.count + 2);	/* ., .. */
	btp->stale = 0;
	blp = xfs_dir2_block_leaf_p(btp);
	endoffset = (uint)((char *)blp - (char *)block);
	/*
	 * Remove the freespace, we'll manage it.
	 */
	xfs_dir2_data_use_free(tp, bp, dup,
		(xfs_dir2_data_aoff_t)((char *)dup - (char *)block),
		be16_to_cpu(dup->length), &needlog, &needscan);
	/*
	 * Create entry for .
	 */
	dep = (xfs_dir2_data_entry_t *)
	      ((char *)block + XFS_DIR2_DATA_DOT_OFFSET);
	dep->inumber = cpu_to_be64(dp->i_ino);
	dep->namelen = 1;
	dep->name[0] = '.';
	tagp = xfs_dir2_data_entry_tag_p(dep);
	*tagp = cpu_to_be16((char *)dep - (char *)block);
	xfs_dir2_data_log_entry(tp, bp, dep);
	blp[0].hashval = cpu_to_be32(xfs_dir_hash_dot);
	blp[0].address = cpu_to_be32(xfs_dir2_byte_to_dataptr(mp,
				(char *)dep - (char *)block));
	/*
	 * Create entry for ..
	 */
	dep = (xfs_dir2_data_entry_t *)
		((char *)block + XFS_DIR2_DATA_DOTDOT_OFFSET);
	dep->inumber = cpu_to_be64(xfs_dir2_sf_get_inumber(sfp, &sfp->hdr.parent));
	dep->namelen = 2;
	dep->name[0] = dep->name[1] = '.';
	tagp = xfs_dir2_data_entry_tag_p(dep);
	*tagp = cpu_to_be16((char *)dep - (char *)block);
	xfs_dir2_data_log_entry(tp, bp, dep);
	blp[1].hashval = cpu_to_be32(xfs_dir_hash_dotdot);
	blp[1].address = cpu_to_be32(xfs_dir2_byte_to_dataptr(mp,
				(char *)dep - (char *)block));
	offset = XFS_DIR2_DATA_FIRST_OFFSET;
	/*
	 * Loop over existing entries, stuff them in.
	 */
	if ((i = 0) == sfp->hdr.count)
		sfep = NULL;
	else
		sfep = xfs_dir2_sf_firstentry(sfp);
	/*
	 * Need to preserve the existing offset values in the sf directory.
	 * Insert holes (unused entries) where necessary.
	 */
	while (offset < endoffset) {
		/*
		 * sfep is null when we reach the end of the list.
		 */
		if (sfep == NULL)
			newoffset = endoffset;
		else
			newoffset = xfs_dir2_sf_get_offset(sfep);
		/*
		 * There should be a hole here, make one.
		 */
		if (offset < newoffset) {
			dup = (xfs_dir2_data_unused_t *)
			      ((char *)block + offset);
			dup->freetag = cpu_to_be16(XFS_DIR2_DATA_FREE_TAG);
			dup->length = cpu_to_be16(newoffset - offset);
			*xfs_dir2_data_unused_tag_p(dup) = cpu_to_be16(
				((char *)dup - (char *)block));
			xfs_dir2_data_log_unused(tp, bp, dup);
			(void)xfs_dir2_data_freeinsert((xfs_dir2_data_t *)block,
				dup, &dummy);
			offset += be16_to_cpu(dup->length);
			continue;
		}
		/*
		 * Copy a real entry.
		 */
		dep = (xfs_dir2_data_entry_t *)((char *)block + newoffset);
		dep->inumber = cpu_to_be64(xfs_dir2_sf_get_inumber(sfp,
				xfs_dir2_sf_inumberp(sfep)));
		dep->namelen = sfep->namelen;
		memcpy(dep->name, sfep->name, dep->namelen);
		tagp = xfs_dir2_data_entry_tag_p(dep);
		*tagp = cpu_to_be16((char *)dep - (char *)block);
		xfs_dir2_data_log_entry(tp, bp, dep);
		blp[2 + i].hashval = cpu_to_be32(xfs_da_hashname(
					(char *)sfep->name, sfep->namelen));
		blp[2 + i].address = cpu_to_be32(xfs_dir2_byte_to_dataptr(mp,
						 (char *)dep - (char *)block));
		offset = (int)((char *)(tagp + 1) - (char *)block);
		if (++i == sfp->hdr.count)
			sfep = NULL;
		else
			sfep = xfs_dir2_sf_nextentry(sfp, sfep);
	}
	/* Done with the temporary buffer */
	kmem_free(buf, buf_len);
	/*
	 * Sort the leaf entries by hash value.
	 */
	xfs_sort(blp, be32_to_cpu(btp->count), sizeof(*blp), xfs_dir2_block_sort);
	/*
	 * Log the leaf entry area and tail.
	 * Already logged the header in data_init, ignore needlog.
	 */
	ASSERT(needscan == 0);
	xfs_dir2_block_log_leaf(tp, bp, 0, be32_to_cpu(btp->count) - 1);
	xfs_dir2_block_log_tail(tp, bp);
	xfs_dir2_data_check(dp, bp);
	xfs_da_buf_done(bp);
	return 0;
}