xfs_dir2.c

linux 内核源代码

	int		v;		/* type-checking value */

	ASSERT((dp->i_d.di_mode & S_IFMT) == S_IFDIR);

	if ((rval = xfs_dir_ino_validate(tp->t_mountp, inum)))
		return rval;

	args.name = name;
	args.namelen = namelen;
	args.hashval = xfs_da_hashname(name, namelen);
	args.inumber = inum;
	args.dp = dp;
	args.firstblock = first;
	args.flist = flist;
	args.total = total;
	args.whichfork = XFS_DATA_FORK;
	args.trans = tp;
	args.justcheck = args.addname = args.oknoent = 0;

	if (dp->i_d.di_format == XFS_DINODE_FMT_LOCAL)
		rval = xfs_dir2_sf_replace(&args);
	else if ((rval = xfs_dir2_isblock(tp, dp, &v)))
		return rval;
	else if (v)
		rval = xfs_dir2_block_replace(&args);
	else if ((rval = xfs_dir2_isleaf(tp, dp, &v)))
		return rval;
	else if (v)
		rval = xfs_dir2_leaf_replace(&args);
	else
		rval = xfs_dir2_node_replace(&args);
	return rval;
}

/*
 * See if this entry can be added to the directory without allocating space.
 */
int
xfs_dir_canenter(
	xfs_trans_t	*tp,
	xfs_inode_t	*dp,
	char		*name,		/* name of entry to add */
	int		namelen)
{
	xfs_da_args_t	args;
	int		rval;
	int		v;		/* type-checking value */

	ASSERT((dp->i_d.di_mode & S_IFMT) == S_IFDIR);

	args.name = name;
	args.namelen = namelen;
	args.hashval = xfs_da_hashname(name, namelen);
	args.inumber = 0;
	args.dp = dp;
	args.firstblock = NULL;
	args.flist = NULL;
	args.total = 0;
	args.whichfork = XFS_DATA_FORK;
	args.trans = tp;
	args.justcheck = args.addname = args.oknoent = 1;

	if (dp->i_d.di_format == XFS_DINODE_FMT_LOCAL)
		rval = xfs_dir2_sf_addname(&args);
	else if ((rval = xfs_dir2_isblock(tp, dp, &v)))
		return rval;
	else if (v)
		rval = xfs_dir2_block_addname(&args);
	else if ((rval = xfs_dir2_isleaf(tp, dp, &v)))
		return rval;
	else if (v)
		rval = xfs_dir2_leaf_addname(&args);
	else
		rval = xfs_dir2_node_addname(&args);
	return rval;
}

/*
 * Utility routines.
 */

/*
 * Add a block to the directory.
 * This routine is for data and free blocks, not leaf/node blocks
 * which are handled by xfs_da_grow_inode.
 */
int
xfs_dir2_grow_inode(
	xfs_da_args_t	*args,
	int		space,		/* v2 dir's space XFS_DIR2_xxx_SPACE */
	xfs_dir2_db_t	*dbp)		/* out: block number added */
{
	xfs_fileoff_t	bno;		/* directory offset of new block */
	int		count;		/* count of filesystem blocks */
	xfs_inode_t	*dp;		/* incore directory inode */
	int		error;
	int		got;		/* blocks actually mapped */
	int		i;
	xfs_bmbt_irec_t	map;		/* single structure for bmap */
	int		mapi;		/* mapping index */
	xfs_bmbt_irec_t	*mapp;		/* bmap mapping structure(s) */
	xfs_mount_t	*mp;
	int		nmap;		/* number of bmap entries */
	xfs_trans_t	*tp;

	xfs_dir2_trace_args_s("grow_inode", args, space);
	dp = args->dp;
	tp = args->trans;
	mp = dp->i_mount;
	/*
	 * Set lowest possible block in the space requested.
	 */
	bno = XFS_B_TO_FSBT(mp, space * XFS_DIR2_SPACE_SIZE);
	count = mp->m_dirblkfsbs;
	/*
	 * Find the first hole for our block.
	 */
	if ((error = xfs_bmap_first_unused(tp, dp, count, &bno, XFS_DATA_FORK)))
		return error;
	nmap = 1;
	ASSERT(args->firstblock != NULL);
	/*
	 * Try mapping the new block contiguously (one extent).
	 */
	if ((error = xfs_bmapi(tp, dp, bno, count,
			XFS_BMAPI_WRITE|XFS_BMAPI_METADATA|XFS_BMAPI_CONTIG,
			args->firstblock, args->total, &map, &nmap,
			args->flist, NULL)))
		return error;
	ASSERT(nmap <= 1);
	if (nmap == 1) {
		mapp = &map;
		mapi = 1;
	}
	/*
	 * Didn't work and this is a multiple-fsb directory block.
	 * Try again with contiguous flag turned on.
	 */
	else if (nmap == 0 && count > 1) {
		xfs_fileoff_t	b;	/* current file offset */

		/*
		 * Space for maximum number of mappings.
		 */
		mapp = kmem_alloc(sizeof(*mapp) * count, KM_SLEEP);
		/*
		 * Iterate until we get to the end of our block.
		 */
		for (b = bno, mapi = 0; b < bno + count; ) {
			int	c;	/* current fsb count */

			/*
			 * Can't map more than MAX_NMAP at once.
			 */
			nmap = MIN(XFS_BMAP_MAX_NMAP, count);
			c = (int)(bno + count - b);
			if ((error = xfs_bmapi(tp, dp, b, c,
					XFS_BMAPI_WRITE|XFS_BMAPI_METADATA,
					args->firstblock, args->total,
					&mapp[mapi], &nmap, args->flist,
					NULL))) {
				kmem_free(mapp, sizeof(*mapp) * count);
				return error;
			}
			if (nmap < 1)
				break;
			/*
			 * Add this bunch into our table, go to the next offset.
			 */
			mapi += nmap;
			b = mapp[mapi - 1].br_startoff +
			    mapp[mapi - 1].br_blockcount;
		}
	}
	/*
	 * Didn't work.
	 */
	else {
		mapi = 0;
		mapp = NULL;
	}
	/*
	 * See how many fsb's we got.
	 */
	for (i = 0, got = 0; i < mapi; i++)
		got += mapp[i].br_blockcount;
	/*
	 * Didn't get enough fsb's, or the first/last block's are wrong.
	 */
	if (got != count || mapp[0].br_startoff != bno ||
	    mapp[mapi - 1].br_startoff + mapp[mapi - 1].br_blockcount !=
	    bno + count) {
		if (mapp != &map)
			kmem_free(mapp, sizeof(*mapp) * count);
		return XFS_ERROR(ENOSPC);
	}
	/*
	 * Done with the temporary mapping table.
	 */
	if (mapp != &map)
		kmem_free(mapp, sizeof(*mapp) * count);
	*dbp = xfs_dir2_da_to_db(mp, (xfs_dablk_t)bno);
	/*
	 * Update file's size if this is the data space and it grew.
	 */
	if (space == XFS_DIR2_DATA_SPACE) {
		xfs_fsize_t	size;		/* directory file (data) size */

		size = XFS_FSB_TO_B(mp, bno + count);
		if (size > dp->i_d.di_size) {
			dp->i_d.di_size = size;
			xfs_trans_log_inode(tp, dp, XFS_ILOG_CORE);
		}
	}
	return 0;
}

/*
 * See if the directory is a single-block form directory.
 */
int
xfs_dir2_isblock(
	xfs_trans_t	*tp,
	xfs_inode_t	*dp,
	int		*vp)		/* out: 1 is block, 0 is not block */
{
	xfs_fileoff_t	last;		/* last file offset */
	xfs_mount_t	*mp;
	int		rval;

	mp = dp->i_mount;
	if ((rval = xfs_bmap_last_offset(tp, dp, &last, XFS_DATA_FORK)))
		return rval;
	rval = XFS_FSB_TO_B(mp, last) == mp->m_dirblksize;
	ASSERT(rval == 0 || dp->i_d.di_size == mp->m_dirblksize);
	*vp = rval;
	return 0;
}

/*
 * See if the directory is a single-leaf form directory.
 */
int
xfs_dir2_isleaf(
	xfs_trans_t	*tp,
	xfs_inode_t	*dp,
	int		*vp)		/* out: 1 is leaf, 0 is not leaf */
{
	xfs_fileoff_t	last;		/* last file offset */
	xfs_mount_t	*mp;
	int		rval;

	mp = dp->i_mount;
	if ((rval = xfs_bmap_last_offset(tp, dp, &last, XFS_DATA_FORK)))
		return rval;
	*vp = last == mp->m_dirleafblk + (1 << mp->m_sb.sb_dirblklog);
	return 0;
}

/*
 * Remove the given block from the directory.
 * This routine is used for data and free blocks, leaf/node are done
 * by xfs_da_shrink_inode.
 */
int
xfs_dir2_shrink_inode(
	xfs_da_args_t	*args,
	xfs_dir2_db_t	db,
	xfs_dabuf_t	*bp)
{
	xfs_fileoff_t	bno;		/* directory file offset */
	xfs_dablk_t	da;		/* directory file offset */
	int		done;		/* bunmap is finished */
	xfs_inode_t	*dp;
	int		error;
	xfs_mount_t	*mp;
	xfs_trans_t	*tp;

	xfs_dir2_trace_args_db("shrink_inode", args, db, bp);
	dp = args->dp;
	mp = dp->i_mount;
	tp = args->trans;
	da = xfs_dir2_db_to_da(mp, db);
	/*
	 * Unmap the fsblock(s).
	 */
	if ((error = xfs_bunmapi(tp, dp, da, mp->m_dirblkfsbs,
			XFS_BMAPI_METADATA, 0, args->firstblock, args->flist,
			NULL, &done))) {
		/*
		 * ENOSPC actually can happen if we're in a removename with
		 * no space reservation, and the resulting block removal
		 * would cause a bmap btree split or conversion from extents
		 * to btree.  This can only happen for un-fragmented
		 * directory blocks, since you need to be punching out
		 * the middle of an extent.
		 * In this case we need to leave the block in the file,
		 * and not binval it.
		 * So the block has to be in a consistent empty state
		 * and appropriately logged.
		 * We don't free up the buffer, the caller can tell it
		 * hasn't happened since it got an error back.
		 */
		return error;
	}
	ASSERT(done);
	/*
	 * Invalidate the buffer from the transaction.
	 */
	xfs_da_binval(tp, bp);
	/*
	 * If it's not a data block, we're done.
	 */
	if (db >= XFS_DIR2_LEAF_FIRSTDB(mp))
		return 0;
	/*
	 * If the block isn't the last one in the directory, we're done.
	 */
	if (dp->i_d.di_size > xfs_dir2_db_off_to_byte(mp, db + 1, 0))
		return 0;
	bno = da;
	if ((error = xfs_bmap_last_before(tp, dp, &bno, XFS_DATA_FORK))) {
		/*
		 * This can't really happen unless there's kernel corruption.
		 */
		return error;
	}
	if (db == mp->m_dirdatablk)
		ASSERT(bno == 0);
	else
		ASSERT(bno > 0);
	/*
	 * Set the size to the new last block.
	 */
	dp->i_d.di_size = XFS_FSB_TO_B(mp, bno);
	xfs_trans_log_inode(tp, dp, XFS_ILOG_CORE);
	return 0;
}