dir.c

ocfs1.2.7 源码

			brelse(bh);
			bh = ocfs2_bread(inode,
					 offset >> sb->s_blocksize_bits, &err, 0);
			if (!bh) {
				mlog(ML_ERROR, "directory #%"MLFu64" contains "
					       "a hole at offset %lu\n",
				     OCFS2_I(inode)->ip_blkno, offset);
				offset += sb->s_blocksize;
				continue;
			}
			de = (struct ocfs2_dir_entry *) bh->b_data;
		}
		if (!ocfs2_check_dir_entry(inode, de, bh, offset)) {
			brelse(bh);
			return 1;
		}
		if (le64_to_cpu(de->inode)) {
			brelse(bh);
			return 0;
		}
		offset += le16_to_cpu(de->rec_len);
		de = (struct ocfs2_dir_entry *)
			((char *)de + le16_to_cpu(de->rec_len));
	}
	brelse(bh);
	return 1;
}

/* returns a bh of the 1st new block in the allocation. */
int ocfs2_do_extend_dir(struct super_block *sb,
			struct ocfs2_journal_handle *handle,
			struct inode *dir,
			struct buffer_head *parent_fe_bh,
			struct ocfs2_alloc_context *data_ac,
			struct ocfs2_alloc_context *meta_ac,
			struct buffer_head **new_bh)
{
	int status;
	int extend;
	u64 p_blkno;

	spin_lock(&OCFS2_I(dir)->ip_lock);
	extend = (i_size_read(dir) == ocfs2_clusters_to_bytes(sb, OCFS2_I(dir)->ip_clusters));
	spin_unlock(&OCFS2_I(dir)->ip_lock);

	if (extend) {
		status = ocfs2_extend_allocation(OCFS2_SB(sb), dir, 1,
						 parent_fe_bh, handle,
						 data_ac, meta_ac, NULL);
		BUG_ON(status == -EAGAIN);
		if (status < 0) {
			mlog_errno(status);
			goto bail;
		}
	}

	status = ocfs2_extent_map_get_blocks(dir, (dir->i_blocks >>
						   (sb->s_blocksize_bits - 9)),
					     1, &p_blkno, NULL);
	if (status < 0) {
		mlog_errno(status);
		goto bail;
	}

	*new_bh = sb_getblk(sb, p_blkno);
	if (!*new_bh) {
		status = -EIO;
		mlog_errno(status);
		goto bail;
	}
	status = 0;
bail:
	mlog_exit(status);
	return status;
}

/* assumes you already have a cluster lock on the directory. */
static int ocfs2_extend_dir(struct ocfs2_super *osb,
			    struct inode *dir,
			    struct buffer_head *parent_fe_bh,
			    struct buffer_head **new_de_bh)
{
	int status = 0;
	int credits, num_free_extents, drop_alloc_sem = 0;
	loff_t dir_i_size;
	struct ocfs2_dinode *fe = (struct ocfs2_dinode *) parent_fe_bh->b_data;
	struct ocfs2_alloc_context *data_ac = NULL;
	struct ocfs2_alloc_context *meta_ac = NULL;
	struct ocfs2_journal_handle *handle = NULL;
	struct buffer_head *new_bh = NULL;
	struct ocfs2_dir_entry * de;
	struct super_block *sb = osb->sb;

	mlog_entry_void();

	dir_i_size = i_size_read(dir);
	mlog(0, "extending dir %"MLFu64" (i_size = %lld)\n",
	     OCFS2_I(dir)->ip_blkno, dir_i_size);

	handle = ocfs2_alloc_handle(osb);
	if (handle == NULL) {
		status = -ENOMEM;
		mlog_errno(status);
		goto bail;
	}

	/* dir->i_size is always block aligned. */
	spin_lock(&OCFS2_I(dir)->ip_lock);
	if (dir_i_size == ocfs2_clusters_to_bytes(sb, OCFS2_I(dir)->ip_clusters)) {
		spin_unlock(&OCFS2_I(dir)->ip_lock);
		num_free_extents = ocfs2_num_free_extents(osb, dir, fe);
		if (num_free_extents < 0) {
			status = num_free_extents;
			mlog_errno(status);
			goto bail;
		}

		if (!num_free_extents) {
			status = ocfs2_reserve_new_metadata(osb, handle,
							    fe, &meta_ac);
			if (status < 0) {
				if (status != -ENOSPC)
					mlog_errno(status);
				goto bail;
			}
		}

		status = ocfs2_reserve_clusters(osb, handle, 1, &data_ac);
		if (status < 0) {
			if (status != -ENOSPC)
				mlog_errno(status);
			goto bail;
		}

		credits = ocfs2_calc_extend_credits(sb, fe, 1);
	} else {
		spin_unlock(&OCFS2_I(dir)->ip_lock);
		credits = OCFS2_SIMPLE_DIR_EXTEND_CREDITS;
	}

	down_write(&OCFS2_I(dir)->ip_alloc_sem);
	drop_alloc_sem = 1;

	handle = ocfs2_start_trans(osb, handle, credits);
	if (IS_ERR(handle)) {
		status = PTR_ERR(handle);
		handle = NULL;
		mlog_errno(status);
		goto bail;
	}

	status = ocfs2_do_extend_dir(osb->sb, handle, dir, parent_fe_bh,
				     data_ac, meta_ac, &new_bh);
	if (status < 0) {
		mlog_errno(status);
		goto bail;
	}

	ocfs2_set_new_buffer_uptodate(dir, new_bh);

	status = ocfs2_journal_access(handle, dir, new_bh,
				      OCFS2_JOURNAL_ACCESS_CREATE);
	if (status < 0) {
		mlog_errno(status);
		goto bail;
	}
	memset(new_bh->b_data, 0, sb->s_blocksize);
	de = (struct ocfs2_dir_entry *) new_bh->b_data;
	de->inode = 0;
	de->rec_len = cpu_to_le16(sb->s_blocksize);
	status = ocfs2_journal_dirty(handle, new_bh);
	if (status < 0) {
		mlog_errno(status);
		goto bail;
	}

	dir_i_size += dir->i_sb->s_blocksize;
	i_size_write(dir, dir_i_size);
	dir->i_blocks = ocfs2_align_bytes_to_sectors(dir_i_size);
	status = ocfs2_mark_inode_dirty(handle, dir, parent_fe_bh);
	if (status < 0) {
		mlog_errno(status);
		goto bail;
	}

	*new_de_bh = new_bh;
	get_bh(*new_de_bh);
bail:
	if (drop_alloc_sem)
		up_write(&OCFS2_I(dir)->ip_alloc_sem);
	if (handle)
		ocfs2_commit_trans(handle);

	if (data_ac)
		ocfs2_free_alloc_context(data_ac);
	if (meta_ac)
		ocfs2_free_alloc_context(meta_ac);

	if (new_bh)
		brelse(new_bh);

	mlog_exit(status);
	return status;
}

/*
 * Search the dir for a good spot, extending it if necessary. The
 * block containing an appropriate record is returned in ret_de_bh.
 */
int ocfs2_prepare_dir_for_insert(struct ocfs2_super *osb,
				 struct inode *dir,
				 struct buffer_head *parent_fe_bh,
				 const char *name,
				 int namelen,
				 struct buffer_head **ret_de_bh)
{
	unsigned long offset;
	struct buffer_head * bh = NULL;
	unsigned short rec_len;
	struct ocfs2_dinode *fe;
	struct ocfs2_dir_entry *de;
	struct super_block *sb;
	int status;

	mlog_entry_void();

	mlog(0, "getting ready to insert namelen %d into dir %"MLFu64"\n",
	     namelen, OCFS2_I(dir)->ip_blkno);

	BUG_ON(!S_ISDIR(dir->i_mode));
	fe = (struct ocfs2_dinode *) parent_fe_bh->b_data;
	BUG_ON(le64_to_cpu(fe->i_size) != i_size_read(dir));

	sb = dir->i_sb;

	if (!namelen) {
		status = -EINVAL;
		mlog_errno(status);
		goto bail;
	}

	bh = ocfs2_bread(dir, 0, &status, 0);
	if (!bh) {
		mlog_errno(status);
		goto bail;
	}

	rec_len = OCFS2_DIR_REC_LEN(namelen);
	offset = 0;
	de = (struct ocfs2_dir_entry *) bh->b_data;
	while (1) {
		if ((char *)de >= sb->s_blocksize + bh->b_data) {
			brelse(bh);
			bh = NULL;

			if (i_size_read(dir) <= offset) {
				status = ocfs2_extend_dir(osb,
							  dir,
							  parent_fe_bh,
							  &bh);
				if (status < 0) {
					mlog_errno(status);
					goto bail;
				}
				BUG_ON(!bh);
				*ret_de_bh = bh;
				get_bh(*ret_de_bh);
				goto bail;
			}
			bh = ocfs2_bread(dir,
					 offset >> sb->s_blocksize_bits,
					 &status,
					 0);
			if (!bh) {
				mlog_errno(status);
				goto bail;
			}
			/* move to next block */
			de = (struct ocfs2_dir_entry *) bh->b_data;
		}
		if (!ocfs2_check_dir_entry(dir, de, bh, offset)) {
			status = -ENOENT;
			goto bail;
		}
		if (ocfs2_match(namelen, name, de)) {
			status = -EEXIST;
			goto bail;
		}
		if (((le64_to_cpu(de->inode) == 0) &&
		     (le16_to_cpu(de->rec_len) >= rec_len)) ||
		    (le16_to_cpu(de->rec_len) >=
		     (OCFS2_DIR_REC_LEN(de->name_len) + rec_len))) {
			/* Ok, we found a spot. Return this bh and let
			 * the caller actually fill it in. */
			*ret_de_bh = bh;
			get_bh(*ret_de_bh);
			status = 0;
			goto bail;
		}
		offset += le16_to_cpu(de->rec_len);
		de = (struct ocfs2_dir_entry *)((char *) de + le16_to_cpu(de->rec_len));
	}

	status = 0;
bail:
	if (bh)
		brelse(bh);

	mlog_exit(status);
	return status;
}