xfs_dir2_leaf.c

linux 内核源代码

			 */
			curdb = xfs_dir2_da_to_db(mp, map->br_startoff);
			error = xfs_da_read_buf(NULL, dp, map->br_startoff,
				map->br_blockcount >= mp->m_dirblkfsbs ?
				    XFS_FSB_TO_DADDR(mp, map->br_startblock) :
				    -1,
				&bp, XFS_DATA_FORK);
			/*
			 * Should just skip over the data block instead
			 * of giving up.
			 */
			if (error)
				break;	/* XXX */
			/*
			 * Adjust the current amount of read-ahead: we just
			 * read a block that was previously ra.
			 */
			if (ra_current)
				ra_current -= mp->m_dirblkfsbs;
			/*
			 * Do we need more readahead?
			 */
			for (ra_index = ra_offset = i = 0;
			     ra_want > ra_current && i < map_blocks;
			     i += mp->m_dirblkfsbs) {
				ASSERT(ra_index < map_valid);
				/*
				 * Read-ahead a contiguous directory block.
				 */
				if (i > ra_current &&
				    map[ra_index].br_blockcount >=
				    mp->m_dirblkfsbs) {
					xfs_baread(mp->m_ddev_targp,
						XFS_FSB_TO_DADDR(mp,
						   map[ra_index].br_startblock +
						   ra_offset),
						(int)BTOBB(mp->m_dirblksize));
					ra_current = i;
				}
				/*
				 * Read-ahead a non-contiguous directory block.
				 * This doesn't use our mapping, but this
				 * is a very rare case.
				 */
				else if (i > ra_current) {
					(void)xfs_da_reada_buf(NULL, dp,
						map[ra_index].br_startoff +
						ra_offset, XFS_DATA_FORK);
					ra_current = i;
				}
				/*
				 * Advance offset through the mapping table.
				 */
				for (j = 0; j < mp->m_dirblkfsbs; j++) {
					/*
					 * The rest of this extent but not
					 * more than a dir block.
					 */
					length = MIN(mp->m_dirblkfsbs,
						(int)(map[ra_index].br_blockcount -
						ra_offset));
					j += length;
					ra_offset += length;
					/*
					 * Advance to the next mapping if
					 * this one is used up.
					 */
					if (ra_offset ==
					    map[ra_index].br_blockcount) {
						ra_offset = 0;
						ra_index++;
					}
				}
			}
			/*
			 * Having done a read, we need to set a new offset.
			 */
			newoff = xfs_dir2_db_off_to_byte(mp, curdb, 0);
			/*
			 * Start of the current block.
			 */
			if (curoff < newoff)
				curoff = newoff;
			/*
			 * Make sure we're in the right block.
			 */
			else if (curoff > newoff)
				ASSERT(xfs_dir2_byte_to_db(mp, curoff) ==
				       curdb);
			data = bp->data;
			xfs_dir2_data_check(dp, bp);
			/*
			 * Find our position in the block.
			 */
			ptr = (char *)&data->u;
			byteoff = xfs_dir2_byte_to_off(mp, curoff);
			/*
			 * Skip past the header.
			 */
			if (byteoff == 0)
				curoff += (uint)sizeof(data->hdr);
			/*
			 * Skip past entries until we reach our offset.
			 */
			else {
				while ((char *)ptr - (char *)data < byteoff) {
					dup = (xfs_dir2_data_unused_t *)ptr;

					if (be16_to_cpu(dup->freetag)
						  == XFS_DIR2_DATA_FREE_TAG) {

						length = be16_to_cpu(dup->length);
						ptr += length;
						continue;
					}
					dep = (xfs_dir2_data_entry_t *)ptr;
					length =
					   xfs_dir2_data_entsize(dep->namelen);
					ptr += length;
				}
				/*
				 * Now set our real offset.
				 */
				curoff =
					xfs_dir2_db_off_to_byte(mp,
					    xfs_dir2_byte_to_db(mp, curoff),
					    (char *)ptr - (char *)data);
				if (ptr >= (char *)data + mp->m_dirblksize) {
					continue;
				}
			}
		}
		/*
		 * We have a pointer to an entry.
		 * Is it a live one?
		 */
		dup = (xfs_dir2_data_unused_t *)ptr;
		/*
		 * No, it's unused, skip over it.
		 */
		if (be16_to_cpu(dup->freetag) == XFS_DIR2_DATA_FREE_TAG) {
			length = be16_to_cpu(dup->length);
			ptr += length;
			curoff += length;
			continue;
		}

		/*
		 * Copy the entry into the putargs, and try formatting it.
		 */
		dep = (xfs_dir2_data_entry_t *)ptr;

		length = xfs_dir2_data_entsize(dep->namelen);

		ino = be64_to_cpu(dep->inumber);
#if XFS_BIG_INUMS
		ino += mp->m_inoadd;
#endif

		/*
		 * Won't fit.  Return to caller.
		 */
		if (filldir(dirent, dep->name, dep->namelen,
			    xfs_dir2_byte_to_dataptr(mp, curoff),
			    ino, DT_UNKNOWN))
			break;

		/*
		 * Advance to next entry in the block.
		 */
		ptr += length;
		curoff += length;
		bufsize -= length;
	}

	/*
	 * All done.  Set output offset value to current offset.
	 */
	if (curoff > xfs_dir2_dataptr_to_byte(mp, XFS_DIR2_MAX_DATAPTR))
		*offset = XFS_DIR2_MAX_DATAPTR;
	else
		*offset = xfs_dir2_byte_to_dataptr(mp, curoff);
	kmem_free(map, map_size * sizeof(*map));
	if (bp)
		xfs_da_brelse(NULL, bp);
	return error;
}

/*
 * Initialize a new leaf block, leaf1 or leafn magic accepted.
 */
int
xfs_dir2_leaf_init(
	xfs_da_args_t		*args,		/* operation arguments */
	xfs_dir2_db_t		bno,		/* directory block number */
	xfs_dabuf_t		**bpp,		/* out: leaf buffer */
	int			magic)		/* magic number for block */
{
	xfs_dabuf_t		*bp;		/* leaf buffer */
	xfs_inode_t		*dp;		/* incore directory inode */
	int			error;		/* error return code */
	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;
	ASSERT(dp != NULL);
	tp = args->trans;
	mp = dp->i_mount;
	ASSERT(bno >= XFS_DIR2_LEAF_FIRSTDB(mp) &&
	       bno < XFS_DIR2_FREE_FIRSTDB(mp));
	/*
	 * Get the buffer for the block.
	 */
	error = xfs_da_get_buf(tp, dp, xfs_dir2_db_to_da(mp, bno), -1, &bp,
		XFS_DATA_FORK);
	if (error) {
		return error;
	}
	ASSERT(bp != NULL);
	leaf = bp->data;
	/*
	 * Initialize the header.
	 */
	leaf->hdr.info.magic = cpu_to_be16(magic);
	leaf->hdr.info.forw = 0;
	leaf->hdr.info.back = 0;
	leaf->hdr.count = 0;
	leaf->hdr.stale = 0;
	xfs_dir2_leaf_log_header(tp, bp);
	/*
	 * If it's a leaf-format directory initialize the tail.
	 * In this case our caller has the real bests table to copy into
	 * the block.
	 */
	if (magic == XFS_DIR2_LEAF1_MAGIC) {
		ltp = xfs_dir2_leaf_tail_p(mp, leaf);
		ltp->bestcount = 0;
		xfs_dir2_leaf_log_tail(tp, bp);
	}
	*bpp = bp;
	return 0;
}

/*
 * Log the bests entries indicated from a leaf1 block.
 */
static void
xfs_dir2_leaf_log_bests(
	xfs_trans_t		*tp,		/* transaction pointer */
	xfs_dabuf_t		*bp,		/* leaf buffer */
	int			first,		/* first entry to log */
	int			last)		/* last entry to log */
{
	__be16			*firstb;	/* pointer to first entry */
	__be16			*lastb;		/* pointer to last entry */
	xfs_dir2_leaf_t		*leaf;		/* leaf structure */
	xfs_dir2_leaf_tail_t	*ltp;		/* leaf tail structure */

	leaf = bp->data;
	ASSERT(be16_to_cpu(leaf->hdr.info.magic) == XFS_DIR2_LEAF1_MAGIC);
	ltp = xfs_dir2_leaf_tail_p(tp->t_mountp, leaf);
	firstb = xfs_dir2_leaf_bests_p(ltp) + first;
	lastb = xfs_dir2_leaf_bests_p(ltp) + last;
	xfs_da_log_buf(tp, bp, (uint)((char *)firstb - (char *)leaf),
		(uint)((char *)lastb - (char *)leaf + sizeof(*lastb) - 1));
}

/*
 * Log the leaf entries indicated from a leaf1 or leafn block.
 */
void
xfs_dir2_leaf_log_ents(
	xfs_trans_t		*tp,		/* transaction pointer */
	xfs_dabuf_t		*bp,		/* leaf buffer */
	int			first,		/* first entry to log */
	int			last)		/* last entry to log */
{
	xfs_dir2_leaf_entry_t	*firstlep;	/* pointer to first entry */
	xfs_dir2_leaf_entry_t	*lastlep;	/* pointer to last entry */
	xfs_dir2_leaf_t		*leaf;		/* leaf structure */

	leaf = bp->data;
	ASSERT(be16_to_cpu(leaf->hdr.info.magic) == XFS_DIR2_LEAF1_MAGIC ||
	       be16_to_cpu(leaf->hdr.info.magic) == XFS_DIR2_LEAFN_MAGIC);
	firstlep = &leaf->ents[first];
	lastlep = &leaf->ents[last];
	xfs_da_log_buf(tp, bp, (uint)((char *)firstlep - (char *)leaf),
		(uint)((char *)lastlep - (char *)leaf + sizeof(*lastlep) - 1));
}

/*
 * Log the header of the leaf1 or leafn block.
 */
void
xfs_dir2_leaf_log_header(
	xfs_trans_t		*tp,		/* transaction pointer */
	xfs_dabuf_t		*bp)		/* leaf buffer */
{
	xfs_dir2_leaf_t		*leaf;		/* leaf structure */

	leaf = bp->data;
	ASSERT(be16_to_cpu(leaf->hdr.info.magic) == XFS_DIR2_LEAF1_MAGIC ||
	       be16_to_cpu(leaf->hdr.info.magic) == XFS_DIR2_LEAFN_MAGIC);
	xfs_da_log_buf(tp, bp, (uint)((char *)&leaf->hdr - (char *)leaf),
		(uint)(sizeof(leaf->hdr) - 1));
}

/*
 * Log the tail of the leaf1 block.
 */
STATIC void
xfs_dir2_leaf_log_tail(
	xfs_trans_t		*tp,		/* transaction pointer */
	xfs_dabuf_t		*bp)		/* leaf buffer */
{
	xfs_dir2_leaf_t		*leaf;		/* leaf structure */
	xfs_dir2_leaf_tail_t	*ltp;		/* leaf tail structure */
	xfs_mount_t		*mp;		/* filesystem mount point */

	mp = tp->t_mountp;
	leaf = bp->data;
	ASSERT(be16_to_cpu(leaf->hdr.info.magic) == XFS_DIR2_LEAF1_MAGIC);
	ltp = xfs_dir2_leaf_tail_p(mp, leaf);
	xfs_da_log_buf(tp, bp, (uint)((char *)ltp - (char *)leaf),
		(uint)(mp->m_dirblksize - 1));
}

/*
 * Look up the entry referred to by args in the leaf format directory.
 * Most of the work is done by the xfs_dir2_leaf_lookup_int routine which
 * is also used by the node-format code.
 */
int
xfs_dir2_leaf_lookup(
	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;		/* found entry index */
	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_lookup", args);
	/*
	 * Look up name in the leaf block, returning both buffers and index.
	 */
	if ((error = xfs_dir2_leaf_lookup_int(args, &lbp, &index, &dbp))) {
		return error;
	}
	tp = args->trans;
	dp = args->dp;
	xfs_dir2_leaf_check(dp, lbp);
	leaf = lbp->data;
	/*
	 * Get to the leaf entry and contained data entry address.
	 */
	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)));
	/*
	 * Return the found inode number.
	 */
	args->inumber = be64_to_cpu(dep->inumber);
	xfs_da_brelse(tp, dbp);
	xfs_da_brelse(tp, lbp);
	return XFS_ERROR(EEXIST);
}

/*
 * Look up name/hash in the leaf block.
 * Fill in indexp with the found index, and dbpp with the data buffer.
 * If not found dbpp will be NULL, and ENOENT comes back.
 * lbpp will always be filled in with the leaf buffer unless there's an error.
 */
static int					/* error */
xfs_dir2_leaf_lookup_int(
	xfs_da_args_t		*args,		/* operation arguments */
	xfs_dabuf_t		**lbpp,		/* out: leaf buffer */
	int			*indexp,	/* out: index in leaf block */
	xfs_dabuf_t		**dbpp)		/* out: data buffer */
{
	xfs_dir2_db_t		curdb;		/* current data block number */
	xfs_dabuf_t		*dbp;		/* data buffer */
	xfs_dir2_data_entry_t	*dep;		/* data entry */
	xfs_inode_t		*dp;		/* incore directory inode */
	int			error;		/* error return code */
	int			index;		/* index in leaf block */
	xfs_dabuf_t		*lbp;		/* leaf buffer */
	xfs_dir2_leaf_entry_t	*lep;		/* leaf entry */
	xfs_dir2_leaf_t		*leaf;		/* leaf structure */
	xfs_mount_t		*mp;		/* filesystem mount point */
	xfs_dir2_db_t		newdb;		/* new data block number */
	xfs_trans_t		*tp;		/* transaction pointer */

	dp = args->dp;
	tp = args->trans;
	mp = dp->i_mount;
	/*
	 * Read the leaf block into the buffer.
	 */
	if ((error =
	    xfs_da_read_buf(tp, dp, mp->m_dirleafblk, -1, &lbp,
		    XFS_DATA_FORK))) {
		return error;
	}
	*lbpp = lbp;
	leaf = lbp->data;
	xfs_dir2_leaf_check(dp, lbp);
	/*
	 * Look for the first leaf entry with our hash value.
	 */
	index = xfs_dir2_leaf_search_hash(args, lbp);
	/*
	 * Loop over all the entries with the right hash value
	 * looking to match the name.
	 */
	for (lep = &leaf->ents[index], dbp = NULL, curdb = -1;
	     index < be16_to_cpu(leaf->hdr.count) && be32_to_cpu(lep->hashval) == args->hashval;
	     lep++, index++) {
		/*
		 * Skip over stale leaf entries.
		 */
		if (be32_to_cpu(lep->address) == XFS_DIR2_NULL_DATAPTR)
			continue;
		/*
		 * Get the new data block number.
		 */
		newdb = xfs_dir2_dataptr_to_db(mp, be32_to_cpu(lep->address));
		/*
		 * If it's not the same as the old data block number,
		 * need to pitch the old one and read the new one.
		 */
		if (newdb != curdb) {
			if (dbp)
				xfs_da_brelse(tp, dbp);
			if ((error =
			    xfs_da_read_buf(tp, dp,
				    xfs_dir2_db_to_da(mp, newdb), -1, &dbp,
				    XFS_DATA_FORK))) {
				xfs_da_brelse(tp, lbp);
				return error;
			}
			xfs_dir2_data_check(dp, dbp);
			curdb = newdb;
		}
		/*
		 * Point to the data entry.
		 */
		dep = (xfs_dir2_data_entry_t *)
		      ((char *)dbp->data +
		       xfs_dir2_dataptr_to_off(mp, be32_to_cpu(lep->address)));
		/*
		 * If it matches then return it.
		 */
		if (dep->namelen == args->namelen &&