xfs_dir2_leaf.c

linux 内核源代码

		    dep->name[0] == args->name[0] &&
		    memcmp(dep->name, args->name, args->namelen) == 0) {
			*dbpp = dbp;
			*indexp = index;
			return 0;
		}
	}
	/*
	 * No match found, return ENOENT.
	 */
	ASSERT(args->oknoent);
	if (dbp)
		xfs_da_brelse(tp, dbp);
	xfs_da_brelse(tp, lbp);
	return XFS_ERROR(ENOENT);
}

/*
 * Remove an entry from a leaf format directory.
 */
int						/* error */
xfs_dir2_leaf_removename(
	xfs_da_args_t		*args)		/* operation arguments */
{
	__be16			*bestsp;	/* leaf block best freespace */
	xfs_dir2_data_t		*data;		/* data block structure */
	xfs_dir2_db_t		db;		/* data block number */
	xfs_dabuf_t		*dbp;		/* data block buffer */
	xfs_dir2_data_entry_t	*dep;		/* data entry structure */
	xfs_inode_t		*dp;		/* incore directory inode */
	int			error;		/* error return code */
	xfs_dir2_db_t		i;		/* temporary data block # */
	int			index;		/* index into leaf entries */
	xfs_dabuf_t		*lbp;		/* leaf buffer */
	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;		/* filesystem mount point */
	int			needlog;	/* need to log data header */
	int			needscan;	/* need to rescan data frees */
	xfs_dir2_data_off_t	oldbest;	/* old value of best free */
	xfs_trans_t		*tp;		/* transaction pointer */

	xfs_dir2_trace_args("leaf_removename", args);
	/*
	 * Lookup the leaf entry, get the leaf and data blocks read in.
	 */
	if ((error = xfs_dir2_leaf_lookup_int(args, &lbp, &index, &dbp))) {
		return error;
	}
	dp = args->dp;
	tp = args->trans;
	mp = dp->i_mount;
	leaf = lbp->data;
	data = dbp->data;
	xfs_dir2_data_check(dp, dbp);
	/*
	 * Point to the leaf entry, use that to point to the data entry.
	 */
	lep = &leaf->ents[index];
	db = xfs_dir2_dataptr_to_db(mp, be32_to_cpu(lep->address));
	dep = (xfs_dir2_data_entry_t *)
	      ((char *)data + xfs_dir2_dataptr_to_off(mp, be32_to_cpu(lep->address)));
	needscan = needlog = 0;
	oldbest = be16_to_cpu(data->hdr.bestfree[0].length);
	ltp = xfs_dir2_leaf_tail_p(mp, leaf);
	bestsp = xfs_dir2_leaf_bests_p(ltp);
	ASSERT(be16_to_cpu(bestsp[db]) == oldbest);
	/*
	 * Mark the former data entry unused.
	 */
	xfs_dir2_data_make_free(tp, dbp,
		(xfs_dir2_data_aoff_t)((char *)dep - (char *)data),
		xfs_dir2_data_entsize(dep->namelen), &needlog, &needscan);
	/*
	 * We just mark the leaf entry stale by putting a null in it.
	 */
	be16_add(&leaf->hdr.stale, 1);
	xfs_dir2_leaf_log_header(tp, lbp);
	lep->address = cpu_to_be32(XFS_DIR2_NULL_DATAPTR);
	xfs_dir2_leaf_log_ents(tp, lbp, index, index);
	/*
	 * Scan the freespace in the data block again if necessary,
	 * log the data block header if necessary.
	 */
	if (needscan)
		xfs_dir2_data_freescan(mp, data, &needlog);
	if (needlog)
		xfs_dir2_data_log_header(tp, dbp);
	/*
	 * If the longest freespace in the data block has changed,
	 * put the new value in the bests table and log that.
	 */
	if (be16_to_cpu(data->hdr.bestfree[0].length) != oldbest) {
		bestsp[db] = data->hdr.bestfree[0].length;
		xfs_dir2_leaf_log_bests(tp, lbp, db, db);
	}
	xfs_dir2_data_check(dp, dbp);
	/*
	 * If the data block is now empty then get rid of the data block.
	 */
	if (be16_to_cpu(data->hdr.bestfree[0].length) ==
	    mp->m_dirblksize - (uint)sizeof(data->hdr)) {
		ASSERT(db != mp->m_dirdatablk);
		if ((error = xfs_dir2_shrink_inode(args, db, dbp))) {
			/*
			 * Nope, can't get rid of it because it caused
			 * allocation of a bmap btree block to do so.
			 * Just go on, returning success, leaving the
			 * empty block in place.
			 */
			if (error == ENOSPC && args->total == 0) {
				xfs_da_buf_done(dbp);
				error = 0;
			}
			xfs_dir2_leaf_check(dp, lbp);
			xfs_da_buf_done(lbp);
			return error;
		}
		dbp = NULL;
		/*
		 * If this is the last data block then compact the
		 * bests table by getting rid of entries.
		 */
		if (db == be32_to_cpu(ltp->bestcount) - 1) {
			/*
			 * Look for the last active entry (i).
			 */
			for (i = db - 1; i > 0; i--) {
				if (be16_to_cpu(bestsp[i]) != NULLDATAOFF)
					break;
			}
			/*
			 * Copy the table down so inactive entries at the
			 * end are removed.
			 */
			memmove(&bestsp[db - i], bestsp,
				(be32_to_cpu(ltp->bestcount) - (db - i)) * sizeof(*bestsp));
			be32_add(&ltp->bestcount, -(db - i));
			xfs_dir2_leaf_log_tail(tp, lbp);
			xfs_dir2_leaf_log_bests(tp, lbp, 0, be32_to_cpu(ltp->bestcount) - 1);
		} else
			bestsp[db] = cpu_to_be16(NULLDATAOFF);
	}
	/*
	 * If the data block was not the first one, drop it.
	 */
	else if (db != mp->m_dirdatablk && dbp != NULL) {
		xfs_da_buf_done(dbp);
		dbp = NULL;
	}
	xfs_dir2_leaf_check(dp, lbp);
	/*
	 * See if we can convert to block form.
	 */
	return xfs_dir2_leaf_to_block(args, lbp, dbp);
}

/*
 * Replace the inode number in a leaf format directory entry.
 */
int						/* error */
xfs_dir2_leaf_replace(
	xfs_da_args_t		*args)		/* operation arguments */
{
	xfs_dabuf_t		*dbp;		/* data block buffer */
	xfs_dir2_data_entry_t	*dep;		/* data block entry */
	xfs_inode_t		*dp;		/* incore directory inode */
	int			error;		/* error return code */
	int			index;		/* index of leaf entry */
	xfs_dabuf_t		*lbp;		/* leaf buffer */
	xfs_dir2_leaf_t		*leaf;		/* leaf structure */
	xfs_dir2_leaf_entry_t	*lep;		/* leaf entry */
	xfs_trans_t		*tp;		/* transaction pointer */

	xfs_dir2_trace_args("leaf_replace", args);
	/*
	 * Look up the entry.
	 */
	if ((error = xfs_dir2_leaf_lookup_int(args, &lbp, &index, &dbp))) {
		return error;
	}
	dp = args->dp;
	leaf = lbp->data;
	/*
	 * Point to the leaf entry, get data address from it.
	 */
	lep = &leaf->ents[index];
	/*
	 * Point to the data entry.
	 */
	dep = (xfs_dir2_data_entry_t *)
	      ((char *)dbp->data +
	       xfs_dir2_dataptr_to_off(dp->i_mount, be32_to_cpu(lep->address)));
	ASSERT(args->inumber != be64_to_cpu(dep->inumber));
	/*
	 * Put the new inode number in, log it.
	 */
	dep->inumber = cpu_to_be64(args->inumber);
	tp = args->trans;
	xfs_dir2_data_log_entry(tp, dbp, dep);
	xfs_da_buf_done(dbp);
	xfs_dir2_leaf_check(dp, lbp);
	xfs_da_brelse(tp, lbp);
	return 0;
}

/*
 * Return index in the leaf block (lbp) which is either the first
 * one with this hash value, or if there are none, the insert point
 * for that hash value.
 */
int						/* index value */
xfs_dir2_leaf_search_hash(
	xfs_da_args_t		*args,		/* operation arguments */
	xfs_dabuf_t		*lbp)		/* leaf buffer */
{
	xfs_dahash_t		hash=0;		/* hash from this entry */
	xfs_dahash_t		hashwant;	/* hash value looking for */
	int			high;		/* high leaf index */
	int			low;		/* low leaf index */
	xfs_dir2_leaf_t		*leaf;		/* leaf structure */
	xfs_dir2_leaf_entry_t	*lep;		/* leaf entry */
	int			mid=0;		/* current leaf index */

	leaf = lbp->data;
#ifndef __KERNEL__
	if (!leaf->hdr.count)
		return 0;
#endif
	/*
	 * Note, the table cannot be empty, so we have to go through the loop.
	 * Binary search the leaf entries looking for our hash value.
	 */
	for (lep = leaf->ents, low = 0, high = be16_to_cpu(leaf->hdr.count) - 1,
		hashwant = args->hashval;
	     low <= high; ) {
		mid = (low + high) >> 1;
		if ((hash = be32_to_cpu(lep[mid].hashval)) == hashwant)
			break;
		if (hash < hashwant)
			low = mid + 1;
		else
			high = mid - 1;
	}
	/*
	 * Found one, back up through all the equal hash values.
	 */
	if (hash == hashwant) {
		while (mid > 0 && be32_to_cpu(lep[mid - 1].hashval) == hashwant) {
			mid--;
		}
	}
	/*
	 * Need to point to an entry higher than ours.
	 */
	else if (hash < hashwant)
		mid++;
	return mid;
}

/*
 * Trim off a trailing data block.  We know it's empty since the leaf
 * freespace table says so.
 */
int						/* error */
xfs_dir2_leaf_trim_data(
	xfs_da_args_t		*args,		/* operation arguments */
	xfs_dabuf_t		*lbp,		/* leaf buffer */
	xfs_dir2_db_t		db)		/* data block number */
{
	__be16			*bestsp;	/* leaf bests table */
#ifdef DEBUG
	xfs_dir2_data_t		*data;		/* data block structure */
#endif
	xfs_dabuf_t		*dbp;		/* data block buffer */
	xfs_inode_t		*dp;		/* incore directory inode */
	int			error;		/* error return value */
	xfs_dir2_leaf_t		*leaf;		/* leaf structure */
	xfs_dir2_leaf_tail_t	*ltp;		/* leaf tail structure */
	xfs_mount_t		*mp;		/* filesystem mount point */
	xfs_trans_t		*tp;		/* transaction pointer */

	dp = args->dp;
	mp = dp->i_mount;
	tp = args->trans;
	/*
	 * Read the offending data block.  We need its buffer.
	 */
	if ((error = xfs_da_read_buf(tp, dp, xfs_dir2_db_to_da(mp, db), -1, &dbp,
			XFS_DATA_FORK))) {
		return error;
	}
#ifdef DEBUG
	data = dbp->data;
	ASSERT(be32_to_cpu(data->hdr.magic) == XFS_DIR2_DATA_MAGIC);
#endif
	/* this seems to be an error
	 * data is only valid if DEBUG is defined?
	 * RMC 09/08/1999
	 */

	leaf = lbp->data;
	ltp = xfs_dir2_leaf_tail_p(mp, leaf);
	ASSERT(be16_to_cpu(data->hdr.bestfree[0].length) ==
	       mp->m_dirblksize - (uint)sizeof(data->hdr));
	ASSERT(db == be32_to_cpu(ltp->bestcount) - 1);
	/*
	 * Get rid of the data block.
	 */
	if ((error = xfs_dir2_shrink_inode(args, db, dbp))) {
		ASSERT(error != ENOSPC);
		xfs_da_brelse(tp, dbp);
		return error;
	}
	/*
	 * Eliminate the last bests entry from the table.
	 */
	bestsp = xfs_dir2_leaf_bests_p(ltp);
	be32_add(&ltp->bestcount, -1);
	memmove(&bestsp[1], &bestsp[0], be32_to_cpu(ltp->bestcount) * sizeof(*bestsp));
	xfs_dir2_leaf_log_tail(tp, lbp);
	xfs_dir2_leaf_log_bests(tp, lbp, 0, be32_to_cpu(ltp->bestcount) - 1);
	return 0;
}

/*
 * Convert node form directory to leaf form directory.
 * The root of the node form dir needs to already be a LEAFN block.
 * Just return if we can't do anything.
 */
int						/* error */
xfs_dir2_node_to_leaf(
	xfs_da_state_t		*state)		/* directory operation state */
{
	xfs_da_args_t		*args;		/* operation arguments */
	xfs_inode_t		*dp;		/* incore directory inode */
	int			error;		/* error return code */
	xfs_dabuf_t		*fbp;		/* buffer for freespace block */
	xfs_fileoff_t		fo;		/* freespace file offset */
	xfs_dir2_free_t		*free;		/* freespace structure */
	xfs_dabuf_t		*lbp;		/* buffer for leaf block */
	xfs_dir2_leaf_tail_t	*ltp;		/* tail of leaf structure */
	xfs_dir2_leaf_t		*leaf;		/* leaf structure */
	xfs_mount_t		*mp;		/* filesystem mount point */
	int			rval;		/* successful free trim? */
	xfs_trans_t		*tp;		/* transaction pointer */

	/*
	 * There's more than a leaf level in the btree, so there must
	 * be multiple leafn blocks.  Give up.
	 */
	if (state->path.active > 1)
		return 0;
	args = state->args;
	xfs_dir2_trace_args("node_to_leaf", args);
	mp = state->mp;
	dp = args->dp;
	tp = args->trans;
	/*
	 * Get the last offset in the file.
	 */
	if ((error = xfs_bmap_last_offset(tp, dp, &fo, XFS_DATA_FORK))) {
		return error;
	}
	fo -= mp->m_dirblkfsbs;
	/*
	 * If there are freespace blocks other than the first one,
	 * take this opportunity to remove trailing empty freespace blocks
	 * that may have been left behind during no-space-reservation
	 * operations.
	 */
	while (fo > mp->m_dirfreeblk) {
		if ((error = xfs_dir2_node_trim_free(args, fo, &rval))) {
			return error;
		}
		if (rval)
			fo -= mp->m_dirblkfsbs;
		else
			return 0;
	}
	/*
	 * Now find the block just before the freespace block.
	 */
	if ((error = xfs_bmap_last_before(tp, dp, &fo, XFS_DATA_FORK))) {
		return error;
	}
	/*
	 * If it's not the single leaf block, give up.
	 */
	if (XFS_FSB_TO_B(mp, fo) > XFS_DIR2_LEAF_OFFSET + mp->m_dirblksize)
		return 0;
	lbp = state->path.blk[0].bp;
	leaf = lbp->data;
	ASSERT(be16_to_cpu(leaf->hdr.info.magic) == XFS_DIR2_LEAFN_MAGIC);
	/*
	 * Read the freespace block.
	 */
	if ((error = xfs_da_read_buf(tp, dp, mp->m_dirfreeblk, -1, &fbp,
			XFS_DATA_FORK))) {
		return error;
	}
	free = fbp->data;
	ASSERT(be32_to_cpu(free->hdr.magic) == XFS_DIR2_FREE_MAGIC);
	ASSERT(!free->hdr.firstdb);
	/*
	 * Now see if the leafn and free data will fit in a leaf1.
	 * If not, release the buffer and give up.
	 */
	if ((uint)sizeof(leaf->hdr) +
	    (be16_to_cpu(leaf->hdr.count) - be16_to_cpu(leaf->hdr.stale)) * (uint)sizeof(leaf->ents[0]) +
	    be32_to_cpu(free->hdr.nvalid) * (uint)sizeof(leaf->bests[0]) +
	    (uint)sizeof(leaf->tail) >
	    mp->m_dirblksize) {
		xfs_da_brelse(tp, fbp);
		return 0;
	}
	/*
	 * If the leaf has any stale entries in it, compress them out.
	 * The compact routine will log the header.
	 */
	if (be16_to_cpu(leaf->hdr.stale))
		xfs_dir2_leaf_compact(args, lbp);
	else
		xfs_dir2_leaf_log_header(tp, lbp);
	leaf->hdr.info.magic = cpu_to_be16(XFS_DIR2_LEAF1_MAGIC);
	/*
	 * Set up the leaf tail from the freespace block.
	 */
	ltp = xfs_dir2_leaf_tail_p(mp, leaf);
	ltp->bestcount = free->hdr.nvalid;
	/*
	 * Set up the leaf bests table.
	 */
	memcpy(xfs_dir2_leaf_bests_p(ltp), free->bests,
		be32_to_cpu(ltp->bestcount) * sizeof(leaf->bests[0]));
	xfs_dir2_leaf_log_bests(tp, lbp, 0, be32_to_cpu(ltp->bestcount) - 1);
	xfs_dir2_leaf_log_tail(tp, lbp);
	xfs_dir2_leaf_check(dp, lbp);
	/*
	 * Get rid of the freespace block.
	 */
	error = xfs_dir2_shrink_inode(args, XFS_DIR2_FREE_FIRSTDB(mp), fbp);
	if (error) {
		/*
		 * This can't fail here because it can only happen when
		 * punching out the middle of an extent, and this is an
		 * isolated block.
		 */
		ASSERT(error != ENOSPC);
		return error;
	}
	fbp = NULL;
	/*
	 * Now see if we can convert the single-leaf directory
	 * down to a block form directory.
	 * This routine always kills the dabuf for the leaf, so
	 * eliminate it from the path.
	 */
	error = xfs_dir2_leaf_to_block(args, lbp, NULL);
	state->path.blk[0].bp = NULL;
	return error;
}