namei.c

linux 内核源代码

			poffset = fibh->soffset + sizeof(struct fileIdentDesc) + liu + lfi;

			if (poffset >= lfi) {
				nameptr = (char *)(fibh->ebh->b_data + poffset - lfi);
			} else {
				nameptr = fname;
				memcpy(nameptr, fi->fileIdent + liu, lfi - poffset);
				memcpy(nameptr + lfi - poffset, fibh->ebh->b_data, poffset);
			}
		}

		if ((cfi->fileCharacteristics & FID_FILE_CHAR_DELETED) != 0) {
			if (((sizeof(struct fileIdentDesc) + liu + lfi + 3) & ~3) == nfidlen) {
				brelse(epos.bh);
				cfi->descTag.tagSerialNum = cpu_to_le16(1);
				cfi->fileVersionNum = cpu_to_le16(1);
				cfi->fileCharacteristics = 0;
				cfi->lengthFileIdent = namelen;
				cfi->lengthOfImpUse = cpu_to_le16(0);
				if (!udf_write_fi(dir, cfi, fi, fibh, NULL, name)) {
					return fi;
				} else {
					*err = -EIO;
					return NULL;
				}
			}
		}

		if (!lfi || !dentry)
			continue;

		if ((flen = udf_get_filename(dir->i_sb, nameptr, fname, lfi)) &&
		    udf_match(flen, fname, dentry->d_name.len, dentry->d_name.name)) {
			if (fibh->sbh != fibh->ebh)
				brelse(fibh->ebh);
			brelse(fibh->sbh);
			brelse(epos.bh);
			*err = -EEXIST;
			return NULL;
		}
	}

add:
	f_pos += nfidlen;

	if (UDF_I_ALLOCTYPE(dir) == ICBTAG_FLAG_AD_IN_ICB &&
	    sb->s_blocksize - fibh->eoffset < nfidlen) {
		brelse(epos.bh);
		epos.bh = NULL;
		fibh->soffset -= udf_ext0_offset(dir);
		fibh->eoffset -= udf_ext0_offset(dir);
		f_pos -= (udf_ext0_offset(dir) >> 2);
		if (fibh->sbh != fibh->ebh)
			brelse(fibh->ebh);
		brelse(fibh->sbh);
		if (!(fibh->sbh = fibh->ebh = udf_expand_dir_adinicb(dir, &block, err)))
			return NULL;
		epos.block = UDF_I_LOCATION(dir);
		eloc.logicalBlockNum = block;
		eloc.partitionReferenceNum = UDF_I_LOCATION(dir).partitionReferenceNum;
		elen = dir->i_sb->s_blocksize;
		epos.offset = udf_file_entry_alloc_offset(dir);
		if (UDF_I_ALLOCTYPE(dir) == ICBTAG_FLAG_AD_SHORT)
			epos.offset += sizeof(short_ad);
		else if (UDF_I_ALLOCTYPE(dir) == ICBTAG_FLAG_AD_LONG)
			epos.offset += sizeof(long_ad);
	}

	if (sb->s_blocksize - fibh->eoffset >= nfidlen) {
		fibh->soffset = fibh->eoffset;
		fibh->eoffset += nfidlen;
		if (fibh->sbh != fibh->ebh) {
			brelse(fibh->sbh);
			fibh->sbh = fibh->ebh;
		}

		if (UDF_I_ALLOCTYPE(dir) == ICBTAG_FLAG_AD_IN_ICB) {
			block = UDF_I_LOCATION(dir).logicalBlockNum;
			fi = (struct fileIdentDesc *)(UDF_I_DATA(dir) + fibh->soffset -
						      udf_ext0_offset(dir) +
						      UDF_I_LENEATTR(dir));
		} else {
			block = eloc.logicalBlockNum + ((elen - 1) >>
							dir->i_sb->s_blocksize_bits);
			fi = (struct fileIdentDesc *)(fibh->sbh->b_data + fibh->soffset);
		}
	} else {
		fibh->soffset = fibh->eoffset - sb->s_blocksize;
		fibh->eoffset += nfidlen - sb->s_blocksize;
		if (fibh->sbh != fibh->ebh) {
			brelse(fibh->sbh);
			fibh->sbh = fibh->ebh;
		}

		block = eloc.logicalBlockNum + ((elen - 1) >>
						dir->i_sb->s_blocksize_bits);
		fibh->ebh = udf_bread(dir, f_pos >> (dir->i_sb->s_blocksize_bits - 2), 1, err);
		if (!fibh->ebh) {
			brelse(epos.bh);
			brelse(fibh->sbh);
			return NULL;
		}

		if (!fibh->soffset) {
			if (udf_next_aext(dir, &epos, &eloc, &elen, 1) ==
			    (EXT_RECORDED_ALLOCATED >> 30)) {
				block = eloc.logicalBlockNum + ((elen - 1) >>
					dir->i_sb->s_blocksize_bits);
			} else {
				block++;
			}

			brelse(fibh->sbh);
			fibh->sbh = fibh->ebh;
			fi = (struct fileIdentDesc *)(fibh->sbh->b_data);
		} else {
			fi = (struct fileIdentDesc *)
				(fibh->sbh->b_data + sb->s_blocksize + fibh->soffset);
		}
	}

	memset(cfi, 0, sizeof(struct fileIdentDesc));
	if (UDF_SB_UDFREV(sb) >= 0x0200)
		udf_new_tag((char *)cfi, TAG_IDENT_FID, 3, 1, block, sizeof(tag));
	else
		udf_new_tag((char *)cfi, TAG_IDENT_FID, 2, 1, block, sizeof(tag));
	cfi->fileVersionNum = cpu_to_le16(1);
	cfi->lengthFileIdent = namelen;
	cfi->lengthOfImpUse = cpu_to_le16(0);
	if (!udf_write_fi(dir, cfi, fi, fibh, NULL, name)) {
		brelse(epos.bh);
		dir->i_size += nfidlen;
		if (UDF_I_ALLOCTYPE(dir) == ICBTAG_FLAG_AD_IN_ICB)
			UDF_I_LENALLOC(dir) += nfidlen;
		mark_inode_dirty(dir);
		return fi;
	} else {
		brelse(epos.bh);
		if (fibh->sbh != fibh->ebh)
			brelse(fibh->ebh);
		brelse(fibh->sbh);
		*err = -EIO;
		return NULL;
	}
}

static int udf_delete_entry(struct inode *inode, struct fileIdentDesc *fi,
			    struct udf_fileident_bh *fibh,
			    struct fileIdentDesc *cfi)
{
	cfi->fileCharacteristics |= FID_FILE_CHAR_DELETED;

	if (UDF_QUERY_FLAG(inode->i_sb, UDF_FLAG_STRICT))
		memset(&(cfi->icb), 0x00, sizeof(long_ad));

	return udf_write_fi(inode, cfi, fi, fibh, NULL, NULL);
}

static int udf_create(struct inode *dir, struct dentry *dentry, int mode,
		      struct nameidata *nd)
{
	struct udf_fileident_bh fibh;
	struct inode *inode;
	struct fileIdentDesc cfi, *fi;
	int err;

	lock_kernel();
	inode = udf_new_inode(dir, mode, &err);
	if (!inode) {
		unlock_kernel();
		return err;
	}

	if (UDF_I_ALLOCTYPE(inode) == ICBTAG_FLAG_AD_IN_ICB)
		inode->i_data.a_ops = &udf_adinicb_aops;
	else
		inode->i_data.a_ops = &udf_aops;
	inode->i_op = &udf_file_inode_operations;
	inode->i_fop = &udf_file_operations;
	inode->i_mode = mode;
	mark_inode_dirty(inode);

	if (!(fi = udf_add_entry(dir, dentry, &fibh, &cfi, &err))) {
		inode->i_nlink--;
		mark_inode_dirty(inode);
		iput(inode);
		unlock_kernel();
		return err;
	}
	cfi.icb.extLength = cpu_to_le32(inode->i_sb->s_blocksize);
	cfi.icb.extLocation = cpu_to_lelb(UDF_I_LOCATION(inode));
	*(__le32 *)((struct allocDescImpUse *)cfi.icb.impUse)->impUse =
		cpu_to_le32(UDF_I_UNIQUE(inode) & 0x00000000FFFFFFFFUL);
	udf_write_fi(dir, &cfi, fi, &fibh, NULL, NULL);
	if (UDF_I_ALLOCTYPE(dir) == ICBTAG_FLAG_AD_IN_ICB) {
		mark_inode_dirty(dir);
	}
	if (fibh.sbh != fibh.ebh)
		brelse(fibh.ebh);
	brelse(fibh.sbh);
	unlock_kernel();
	d_instantiate(dentry, inode);

	return 0;
}

static int udf_mknod(struct inode *dir, struct dentry *dentry, int mode,
		     dev_t rdev)
{
	struct inode *inode;
	struct udf_fileident_bh fibh;
	struct fileIdentDesc cfi, *fi;
	int err;

	if (!old_valid_dev(rdev))
		return -EINVAL;

	lock_kernel();
	err = -EIO;
	inode = udf_new_inode(dir, mode, &err);
	if (!inode)
		goto out;

	inode->i_uid = current->fsuid;
	init_special_inode(inode, mode, rdev);
	if (!(fi = udf_add_entry(dir, dentry, &fibh, &cfi, &err))) {
		inode->i_nlink--;
		mark_inode_dirty(inode);
		iput(inode);
		unlock_kernel();
		return err;
	}
	cfi.icb.extLength = cpu_to_le32(inode->i_sb->s_blocksize);
	cfi.icb.extLocation = cpu_to_lelb(UDF_I_LOCATION(inode));
	*(__le32 *)((struct allocDescImpUse *)cfi.icb.impUse)->impUse =
		cpu_to_le32(UDF_I_UNIQUE(inode) & 0x00000000FFFFFFFFUL);
	udf_write_fi(dir, &cfi, fi, &fibh, NULL, NULL);
	if (UDF_I_ALLOCTYPE(dir) == ICBTAG_FLAG_AD_IN_ICB) {
		mark_inode_dirty(dir);
	}
	mark_inode_dirty(inode);

	if (fibh.sbh != fibh.ebh)
		brelse(fibh.ebh);
	brelse(fibh.sbh);
	d_instantiate(dentry, inode);
	err = 0;

out:
	unlock_kernel();
	return err;
}

static int udf_mkdir(struct inode *dir, struct dentry *dentry, int mode)
{
	struct inode *inode;
	struct udf_fileident_bh fibh;
	struct fileIdentDesc cfi, *fi;
	int err;

	lock_kernel();
	err = -EMLINK;
	if (dir->i_nlink >= (256 << sizeof(dir->i_nlink)) - 1)
		goto out;

	err = -EIO;
	inode = udf_new_inode(dir, S_IFDIR, &err);
	if (!inode)
		goto out;

	inode->i_op = &udf_dir_inode_operations;
	inode->i_fop = &udf_dir_operations;
	if (!(fi = udf_add_entry(inode, NULL, &fibh, &cfi, &err))) {
		inode->i_nlink--;
		mark_inode_dirty(inode);
		iput(inode);
		goto out;
	}
	inode->i_nlink = 2;
	cfi.icb.extLength = cpu_to_le32(inode->i_sb->s_blocksize);
	cfi.icb.extLocation = cpu_to_lelb(UDF_I_LOCATION(dir));
	*(__le32 *)((struct allocDescImpUse *)cfi.icb.impUse)->impUse =
		cpu_to_le32(UDF_I_UNIQUE(dir) & 0x00000000FFFFFFFFUL);
	cfi.fileCharacteristics = FID_FILE_CHAR_DIRECTORY | FID_FILE_CHAR_PARENT;
	udf_write_fi(inode, &cfi, fi, &fibh, NULL, NULL);
	brelse(fibh.sbh);
	inode->i_mode = S_IFDIR | mode;
	if (dir->i_mode & S_ISGID)
		inode->i_mode |= S_ISGID;
	mark_inode_dirty(inode);

	if (!(fi = udf_add_entry(dir, dentry, &fibh, &cfi, &err))) {
		inode->i_nlink = 0;
		mark_inode_dirty(inode);
		iput(inode);
		goto out;
	}
	cfi.icb.extLength = cpu_to_le32(inode->i_sb->s_blocksize);
	cfi.icb.extLocation = cpu_to_lelb(UDF_I_LOCATION(inode));
	*(__le32 *)((struct allocDescImpUse *)cfi.icb.impUse)->impUse =
		cpu_to_le32(UDF_I_UNIQUE(inode) & 0x00000000FFFFFFFFUL);
	cfi.fileCharacteristics |= FID_FILE_CHAR_DIRECTORY;
	udf_write_fi(dir, &cfi, fi, &fibh, NULL, NULL);
	inc_nlink(dir);
	mark_inode_dirty(dir);
	d_instantiate(dentry, inode);
	if (fibh.sbh != fibh.ebh)
		brelse(fibh.ebh);
	brelse(fibh.sbh);
	err = 0;

out:
	unlock_kernel();
	return err;
}

static int empty_dir(struct inode *dir)
{
	struct fileIdentDesc *fi, cfi;
	struct udf_fileident_bh fibh;
	loff_t f_pos;
	loff_t size = (udf_ext0_offset(dir) + dir->i_size) >> 2;
	int block;
	kernel_lb_addr eloc;
	uint32_t elen;
	sector_t offset;
	struct extent_position epos = {};

	f_pos = (udf_ext0_offset(dir) >> 2);

	fibh.soffset = fibh.eoffset = (f_pos & ((dir->i_sb->s_blocksize - 1) >> 2)) << 2;

	if (UDF_I_ALLOCTYPE(dir) == ICBTAG_FLAG_AD_IN_ICB) {
		fibh.sbh = fibh.ebh = NULL;
	} else if (inode_bmap(dir, f_pos >> (dir->i_sb->s_blocksize_bits - 2),
			      &epos, &eloc, &elen, &offset) == (EXT_RECORDED_ALLOCATED >> 30)) {
		block = udf_get_lb_pblock(dir->i_sb, eloc, offset);
		if ((++offset << dir->i_sb->s_blocksize_bits) < elen) {
			if (UDF_I_ALLOCTYPE(dir) == ICBTAG_FLAG_AD_SHORT)
				epos.offset -= sizeof(short_ad);
			else if (UDF_I_ALLOCTYPE(dir) == ICBTAG_FLAG_AD_LONG)
				epos.offset -= sizeof(long_ad);
		} else {
			offset = 0;
		}

		if (!(fibh.sbh = fibh.ebh = udf_tread(dir->i_sb, block))) {
			brelse(epos.bh);
			return 0;
		}
	} else {
		brelse(epos.bh);
		return 0;
	}

	while ((f_pos < size)) {
		fi = udf_fileident_read(dir, &f_pos, &fibh, &cfi, &epos, &eloc,
					&elen, &offset);
		if (!fi) {
			if (fibh.sbh != fibh.ebh)
				brelse(fibh.ebh);
			brelse(fibh.sbh);
			brelse(epos.bh);
			return 0;
		}

		if (cfi.lengthFileIdent &&
		    (cfi.fileCharacteristics & FID_FILE_CHAR_DELETED) == 0) {
			if (fibh.sbh != fibh.ebh)
				brelse(fibh.ebh);
			brelse(fibh.sbh);
			brelse(epos.bh);
			return 0;
		}
	}

	if (fibh.sbh != fibh.ebh)
		brelse(fibh.ebh);
	brelse(fibh.sbh);
	brelse(epos.bh);

	return 1;
}

static int udf_rmdir(struct inode *dir, struct dentry *dentry)
{
	int retval;
	struct inode *inode = dentry->d_inode;
	struct udf_fileident_bh fibh;
	struct fileIdentDesc *fi, cfi;
	kernel_lb_addr tloc;

	retval = -ENOENT;
	lock_kernel();
	fi = udf_find_entry(dir, dentry, &fibh, &cfi);
	if (!fi)
		goto out;

	retval = -EIO;
	tloc = lelb_to_cpu(cfi.icb.extLocation);
	if (udf_get_lb_pblock(dir->i_sb, tloc, 0) != inode->i_ino)
		goto end_rmdir;
	retval = -ENOTEMPTY;
	if (!empty_dir(inode))
		goto end_rmdir;
	retval = udf_delete_entry(dir, fi, &fibh, &cfi);
	if (retval)
		goto end_rmdir;
	if (inode->i_nlink != 2)
		udf_warning(inode->i_sb, "udf_rmdir",
			    "empty directory has nlink != 2 (%d)",
			    inode->i_nlink);
	clear_nlink(inode);
	inode->i_size = 0;
	inode_dec_link_count(dir);