dir.c

linux 内核源代码

			return PTR_ERR(dent);
		if (ip) {
			if (be64_to_cpu(dent->de_inum.no_addr) != ip->i_no_addr)
				goto out;
			if (be64_to_cpu(dent->de_inum.no_formal_ino) !=
			    ip->i_no_formal_ino)
				goto out;
			if (unlikely(IF2DT(ip->i_inode.i_mode) !=
			    be16_to_cpu(dent->de_type))) {
				gfs2_consist_inode(GFS2_I(dir));
				ret = -EIO;
				goto out;
			}
		}
		ret = 0;
out:
		brelse(bh);
	}
	return ret;
}

static int dir_new_leaf(struct inode *inode, const struct qstr *name)
{
	struct buffer_head *bh, *obh;
	struct gfs2_inode *ip = GFS2_I(inode);
	struct gfs2_leaf *leaf, *oleaf;
	int error;
	u32 index;
	u64 bn;

	index = name->hash >> (32 - ip->i_di.di_depth);
	error = get_first_leaf(ip, index, &obh);
	if (error)
		return error;
	do {
		oleaf = (struct gfs2_leaf *)obh->b_data;
		bn = be64_to_cpu(oleaf->lf_next);
		if (!bn)
			break;
		brelse(obh);
		error = get_leaf(ip, bn, &obh);
		if (error)
			return error;
	} while(1);

	gfs2_trans_add_bh(ip->i_gl, obh, 1);

	leaf = new_leaf(inode, &bh, be16_to_cpu(oleaf->lf_depth));
	if (!leaf) {
		brelse(obh);
		return -ENOSPC;
	}
	oleaf->lf_next = cpu_to_be64(bh->b_blocknr);
	brelse(bh);
	brelse(obh);

	error = gfs2_meta_inode_buffer(ip, &bh);
	if (error)
		return error;
	gfs2_trans_add_bh(ip->i_gl, bh, 1);
	ip->i_di.di_blocks++;
	gfs2_set_inode_blocks(&ip->i_inode);
	gfs2_dinode_out(ip, bh->b_data);
	brelse(bh);
	return 0;
}

/**
 * gfs2_dir_add - Add new filename into directory
 * @dip: The GFS2 inode
 * @filename: The new name
 * @inode: The inode number of the entry
 * @type: The type of the entry
 *
 * Returns: 0 on success, error code on failure
 */

int gfs2_dir_add(struct inode *inode, const struct qstr *name,
		 const struct gfs2_inode *nip, unsigned type)
{
	struct gfs2_inode *ip = GFS2_I(inode);
	struct buffer_head *bh;
	struct gfs2_dirent *dent;
	struct gfs2_leaf *leaf;
	int error;

	while(1) {
		dent = gfs2_dirent_search(inode, name, gfs2_dirent_find_space,
					  &bh);
		if (dent) {
			if (IS_ERR(dent))
				return PTR_ERR(dent);
			dent = gfs2_init_dirent(inode, dent, name, bh);
			gfs2_inum_out(nip, dent);
			dent->de_type = cpu_to_be16(type);
			if (ip->i_di.di_flags & GFS2_DIF_EXHASH) {
				leaf = (struct gfs2_leaf *)bh->b_data;
				leaf->lf_entries = cpu_to_be16(be16_to_cpu(leaf->lf_entries) + 1);
			}
			brelse(bh);
			error = gfs2_meta_inode_buffer(ip, &bh);
			if (error)
				break;
			gfs2_trans_add_bh(ip->i_gl, bh, 1);
			ip->i_di.di_entries++;
			ip->i_inode.i_mtime = ip->i_inode.i_ctime = CURRENT_TIME;
			gfs2_dinode_out(ip, bh->b_data);
			brelse(bh);
			error = 0;
			break;
		}
		if (!(ip->i_di.di_flags & GFS2_DIF_EXHASH)) {
			error = dir_make_exhash(inode);
			if (error)
				break;
			continue;
		}
		error = dir_split_leaf(inode, name);
		if (error == 0)
			continue;
		if (error < 0)
			break;
		if (ip->i_di.di_depth < GFS2_DIR_MAX_DEPTH) {
			error = dir_double_exhash(ip);
			if (error)
				break;
			error = dir_split_leaf(inode, name);
			if (error < 0)
				break;
			if (error == 0)
				continue;
		}
		error = dir_new_leaf(inode, name);
		if (!error)
			continue;
		error = -ENOSPC;
		break;
	}
	return error;
}


/**
 * gfs2_dir_del - Delete a directory entry
 * @dip: The GFS2 inode
 * @filename: The filename
 *
 * Returns: 0 on success, error code on failure
 */

int gfs2_dir_del(struct gfs2_inode *dip, const struct qstr *name)
{
	struct gfs2_dirent *dent, *prev = NULL;
	struct buffer_head *bh;
	int error;

	/* Returns _either_ the entry (if its first in block) or the
	   previous entry otherwise */
	dent = gfs2_dirent_search(&dip->i_inode, name, gfs2_dirent_prev, &bh);
	if (!dent) {
		gfs2_consist_inode(dip);
		return -EIO;
	}
	if (IS_ERR(dent)) {
		gfs2_consist_inode(dip);
		return PTR_ERR(dent);
	}
	/* If not first in block, adjust pointers accordingly */
	if (gfs2_dirent_find(dent, name, NULL) == 0) {
		prev = dent;
		dent = (struct gfs2_dirent *)((char *)dent + be16_to_cpu(prev->de_rec_len));
	}

	dirent_del(dip, bh, prev, dent);
	if (dip->i_di.di_flags & GFS2_DIF_EXHASH) {
		struct gfs2_leaf *leaf = (struct gfs2_leaf *)bh->b_data;
		u16 entries = be16_to_cpu(leaf->lf_entries);
		if (!entries)
			gfs2_consist_inode(dip);
		leaf->lf_entries = cpu_to_be16(--entries);
	}
	brelse(bh);

	error = gfs2_meta_inode_buffer(dip, &bh);
	if (error)
		return error;

	if (!dip->i_di.di_entries)
		gfs2_consist_inode(dip);
	gfs2_trans_add_bh(dip->i_gl, bh, 1);
	dip->i_di.di_entries--;
	dip->i_inode.i_mtime = dip->i_inode.i_ctime = CURRENT_TIME;
	gfs2_dinode_out(dip, bh->b_data);
	brelse(bh);
	mark_inode_dirty(&dip->i_inode);

	return error;
}

/**
 * gfs2_dir_mvino - Change inode number of directory entry
 * @dip: The GFS2 inode
 * @filename:
 * @new_inode:
 *
 * This routine changes the inode number of a directory entry.  It's used
 * by rename to change ".." when a directory is moved.
 * Assumes a glock is held on dvp.
 *
 * Returns: errno
 */

int gfs2_dir_mvino(struct gfs2_inode *dip, const struct qstr *filename,
		   const struct gfs2_inode *nip, unsigned int new_type)
{
	struct buffer_head *bh;
	struct gfs2_dirent *dent;
	int error;

	dent = gfs2_dirent_search(&dip->i_inode, filename, gfs2_dirent_find, &bh);
	if (!dent) {
		gfs2_consist_inode(dip);
		return -EIO;
	}
	if (IS_ERR(dent))
		return PTR_ERR(dent);

	gfs2_trans_add_bh(dip->i_gl, bh, 1);
	gfs2_inum_out(nip, dent);
	dent->de_type = cpu_to_be16(new_type);

	if (dip->i_di.di_flags & GFS2_DIF_EXHASH) {
		brelse(bh);
		error = gfs2_meta_inode_buffer(dip, &bh);
		if (error)
			return error;
		gfs2_trans_add_bh(dip->i_gl, bh, 1);
	}

	dip->i_inode.i_mtime = dip->i_inode.i_ctime = CURRENT_TIME;
	gfs2_dinode_out(dip, bh->b_data);
	brelse(bh);
	return 0;
}

/**
 * foreach_leaf - call a function for each leaf in a directory
 * @dip: the directory
 * @lc: the function to call for each each
 * @data: private data to pass to it
 *
 * Returns: errno
 */

static int foreach_leaf(struct gfs2_inode *dip, leaf_call_t lc, void *data)
{
	struct gfs2_sbd *sdp = GFS2_SB(&dip->i_inode);
	struct buffer_head *bh;
	struct gfs2_leaf *leaf;
	u32 hsize, len;
	u32 ht_offset, lp_offset, ht_offset_cur = -1;
	u32 index = 0;
	__be64 *lp;
	u64 leaf_no;
	int error = 0;

	hsize = 1 << dip->i_di.di_depth;
	if (hsize * sizeof(u64) != dip->i_di.di_size) {
		gfs2_consist_inode(dip);
		return -EIO;
	}

	lp = kmalloc(sdp->sd_hash_bsize, GFP_KERNEL);
	if (!lp)
		return -ENOMEM;

	while (index < hsize) {
		lp_offset = index & (sdp->sd_hash_ptrs - 1);
		ht_offset = index - lp_offset;

		if (ht_offset_cur != ht_offset) {
			error = gfs2_dir_read_data(dip, (char *)lp,
						ht_offset * sizeof(__be64),
						sdp->sd_hash_bsize, 1);
			if (error != sdp->sd_hash_bsize) {
				if (error >= 0)
					error = -EIO;
				goto out;
			}
			ht_offset_cur = ht_offset;
		}

		leaf_no = be64_to_cpu(lp[lp_offset]);
		if (leaf_no) {
			error = get_leaf(dip, leaf_no, &bh);
			if (error)
				goto out;
			leaf = (struct gfs2_leaf *)bh->b_data;
			len = 1 << (dip->i_di.di_depth - be16_to_cpu(leaf->lf_depth));
			brelse(bh);

			error = lc(dip, index, len, leaf_no, data);
			if (error)
				goto out;

			index = (index & ~(len - 1)) + len;
		} else
			index++;
	}

	if (index != hsize) {
		gfs2_consist_inode(dip);
		error = -EIO;
	}

out:
	kfree(lp);

	return error;
}

/**
 * leaf_dealloc - Deallocate a directory leaf
 * @dip: the directory
 * @index: the hash table offset in the directory
 * @len: the number of pointers to this leaf
 * @leaf_no: the leaf number
 * @data: not used
 *
 * Returns: errno
 */

static int leaf_dealloc(struct gfs2_inode *dip, u32 index, u32 len,
			u64 leaf_no, void *data)
{
	struct gfs2_sbd *sdp = GFS2_SB(&dip->i_inode);
	struct gfs2_leaf *tmp_leaf;
	struct gfs2_rgrp_list rlist;
	struct buffer_head *bh, *dibh;
	u64 blk, nblk;
	unsigned int rg_blocks = 0, l_blocks = 0;
	char *ht;
	unsigned int x, size = len * sizeof(u64);
	int error;

	memset(&rlist, 0, sizeof(struct gfs2_rgrp_list));

	ht = kzalloc(size, GFP_KERNEL);
	if (!ht)
		return -ENOMEM;

	gfs2_alloc_get(dip);

	error = gfs2_quota_hold(dip, NO_QUOTA_CHANGE, NO_QUOTA_CHANGE);
	if (error)
		goto out;

	error = gfs2_rindex_hold(sdp, &dip->i_alloc.al_ri_gh);
	if (error)
		goto out_qs;

	/*  Count the number of leaves  */

	for (blk = leaf_no; blk; blk = nblk) {
		error = get_leaf(dip, blk, &bh);
		if (error)
			goto out_rlist;
		tmp_leaf = (struct gfs2_leaf *)bh->b_data;
		nblk = be64_to_cpu(tmp_leaf->lf_next);
		brelse(bh);

		gfs2_rlist_add(sdp, &rlist, blk);
		l_blocks++;
	}

	gfs2_rlist_alloc(&rlist, LM_ST_EXCLUSIVE, 0);

	for (x = 0; x < rlist.rl_rgrps; x++) {
		struct gfs2_rgrpd *rgd;
		rgd = rlist.rl_ghs[x].gh_gl->gl_object;
		rg_blocks += rgd->rd_length;
	}

	error = gfs2_glock_nq_m(rlist.rl_rgrps, rlist.rl_ghs);
	if (error)
		goto out_rlist;

	error = gfs2_trans_begin(sdp,
			rg_blocks + (DIV_ROUND_UP(size, sdp->sd_jbsize) + 1) +
			RES_DINODE + RES_STATFS + RES_QUOTA, l_blocks);
	if (error)
		goto out_rg_gunlock;

	for (blk = leaf_no; blk; blk = nblk) {
		error = get_leaf(dip, blk, &bh);
		if (error)
			goto out_end_trans;
		tmp_leaf = (struct gfs2_leaf *)bh->b_data;
		nblk = be64_to_cpu(tmp_leaf->lf_next);
		brelse(bh);

		gfs2_free_meta(dip, blk, 1);

		if (!dip->i_di.di_blocks)
			gfs2_consist_inode(dip);
		dip->i_di.di_blocks--;
		gfs2_set_inode_blocks(&dip->i_inode);
	}

	error = gfs2_dir_write_data(dip, ht, index * sizeof(u64), size);
	if (error != size) {
		if (error >= 0)
			error = -EIO;
		goto out_end_trans;
	}

	error = gfs2_meta_inode_buffer(dip, &dibh);
	if (error)
		goto out_end_trans;

	gfs2_trans_add_bh(dip->i_gl, dibh, 1);
	gfs2_dinode_out(dip, dibh->b_data);
	brelse(dibh);

out_end_trans:
	gfs2_trans_end(sdp);
out_rg_gunlock:
	gfs2_glock_dq_m(rlist.rl_rgrps, rlist.rl_ghs);
out_rlist:
	gfs2_rlist_free(&rlist);
	gfs2_glock_dq_uninit(&dip->i_alloc.al_ri_gh);
out_qs:
	gfs2_quota_unhold(dip);
out:
	gfs2_alloc_put(dip);
	kfree(ht);
	return error;
}

/**
 * gfs2_dir_exhash_dealloc - free all the leaf blocks in a directory
 * @dip: the directory
 *
 * Dealloc all on-disk directory leaves to FREEMETA state
 * Change on-disk inode type to "regular file"
 *
 * Returns: errno
 */

int gfs2_dir_exhash_dealloc(struct gfs2_inode *dip)
{
	struct gfs2_sbd *sdp = GFS2_SB(&dip->i_inode);
	struct buffer_head *bh;
	int error;

	/* Dealloc on-disk leaves to FREEMETA state */
	error = foreach_leaf(dip, leaf_dealloc, NULL);
	if (error)
		return error;

	/* Make this a regular file in case we crash.
	   (We don't want to free these blocks a second time.)  */

	error = gfs2_trans_begin(sdp, RES_DINODE, 0);
	if (error)
		return error;

	error = gfs2_meta_inode_buffer(dip, &bh);
	if (!error) {
		gfs2_trans_add_bh(dip->i_gl, bh, 1);
		((struct gfs2_dinode *)bh->b_data)->di_mode =
						cpu_to_be32(S_IFREG);
		brelse(bh);
	}

	gfs2_trans_end(sdp);

	return error;
}

/**
 * gfs2_diradd_alloc_required - find if adding entry will require an allocation
 * @ip: the file being written to
 * @filname: the filename that's going to be added
 *
 * Returns: 1 if alloc required, 0 if not, -ve on error
 */

int gfs2_diradd_alloc_required(struct inode *inode, const struct qstr *name)
{
	struct gfs2_dirent *dent;
	struct buffer_head *bh;

	dent = gfs2_dirent_search(inode, name, gfs2_dirent_find_space, &bh);
	if (!dent) {
		return 1;
	}
	if (IS_ERR(dent))
		return PTR_ERR(dent);
	brelse(bh);
	return 0;
}