Commit d244bf2d authored by Pavel Shilovsky's avatar Pavel Shilovsky Committed by Steve French
Browse files

CIFS: Implement follow_link for nounix CIFS mounts 



by using a query reparse ioctl request.

Acked-by: default avatarJeff Layton <jlayton@redhat.com>
Signed-off-by: default avatarPavel Shilovsky <pshilovsky@samba.org>
Signed-off-by: default avatarSteve French <smfrench@gmail.com>
parent b42bf888

fs/cifs/cifspdu.h

+6 −5
Original line number Diff line number Diff line
@@ -1495,11 +1495,12 @@ struct reparse_data { 
	__u32	ReparseTag;

	__u16	ReparseDataLength;

	__u16	Reserved;

	__u16	AltNameOffset;

	__u16	AltNameLen;

	__u16	TargetNameOffset;

	__u16	TargetNameLen;

	char	LinkNamesBuf[1];

	__u16	SubstituteNameOffset;

	__u16	SubstituteNameLength;

	__u16	PrintNameOffset;

	__u16	PrintNameLength;

	__u32	Flags;

	char	PathBuffer[0];

} __attribute__((packed));



struct cifs_quota_data {

fs/cifs/cifsproto.h

+3 −7
Original line number Diff line number Diff line
@@ -357,13 +357,9 @@ extern int CIFSSMBUnixQuerySymLink(const unsigned int xid, 
			struct cifs_tcon *tcon,

			const unsigned char *searchName, char **syminfo,

			const struct nls_table *nls_codepage);

#ifdef CONFIG_CIFS_SYMLINK_EXPERIMENTAL

extern int CIFSSMBQueryReparseLinkInfo(const unsigned int xid,

			struct cifs_tcon *tcon,

			const unsigned char *searchName,

			char *symlinkinfo, const int buflen, __u16 fid,

extern int CIFSSMBQuerySymLink(const unsigned int xid, struct cifs_tcon *tcon,

			       __u16 fid, char **symlinkinfo,

			       const struct nls_table *nls_codepage);

#endif /* temporarily unused until cifs_symlink fixed */

extern int CIFSSMBOpen(const unsigned int xid, struct cifs_tcon *tcon,

			const char *fileName, const int disposition,

			const int access_flags, const int omode,

fs/cifs/cifssmb.c

+51 −59
Original line number Diff line number Diff line
@@ -3067,7 +3067,6 @@ CIFSSMBUnixQuerySymLink(const unsigned int xid, struct cifs_tcon *tcon, 
	return rc;

}



#ifdef CONFIG_CIFS_SYMLINK_EXPERIMENTAL

/*

 *	Recent Windows versions now create symlinks more frequently

 *	and they use the "reparse point" mechanism below.  We can of course
@@ -3079,18 +3078,22 @@ CIFSSMBUnixQuerySymLink(const unsigned int xid, struct cifs_tcon *tcon, 
 *	it is not compiled in by default until callers fixed up and more tested.

 */

int

CIFSSMBQueryReparseLinkInfo(const unsigned int xid, struct cifs_tcon *tcon,

			const unsigned char *searchName,

			char *symlinkinfo, const int buflen, __u16 fid,

CIFSSMBQuerySymLink(const unsigned int xid, struct cifs_tcon *tcon,

		    __u16 fid, char **symlinkinfo,

		    const struct nls_table *nls_codepage)

{

	int rc = 0;

	int bytes_returned;

	struct smb_com_transaction_ioctl_req *pSMB;

	struct smb_com_transaction_ioctl_rsp *pSMBr;

	bool is_unicode;

	unsigned int sub_len;

	char *sub_start;

	struct reparse_data *reparse_buf;

	__u32 data_offset, data_count;

	char *end_of_smb;



	cifs_dbg(FYI, "In Windows reparse style QueryLink for path %s\n",

		 searchName);

	cifs_dbg(FYI, "In Windows reparse style QueryLink for fid %u\n", fid);

	rc = smb_init(SMB_COM_NT_TRANSACT, 23, tcon, (void **) &pSMB,

		      (void **) &pSMBr);

	if (rc)
@@ -3119,66 +3122,55 @@ CIFSSMBQueryReparseLinkInfo(const unsigned int xid, struct cifs_tcon *tcon, 
			 (struct smb_hdr *) pSMBr, &bytes_returned, 0);

	if (rc) {

		cifs_dbg(FYI, "Send error in QueryReparseLinkInfo = %d\n", rc);

	} else {		/* decode response */

		__u32 data_offset = le32_to_cpu(pSMBr->DataOffset);

		__u32 data_count = le32_to_cpu(pSMBr->DataCount);

		goto qreparse_out;

	}



	data_offset = le32_to_cpu(pSMBr->DataOffset);

	data_count = le32_to_cpu(pSMBr->DataCount);

	if (get_bcc(&pSMBr->hdr) < 2 || data_offset > 512) {

		/* BB also check enough total bytes returned */

		rc = -EIO;	/* bad smb */

		goto qreparse_out;

	}

		if (data_count && (data_count < 2048)) {

			char *end_of_smb = 2 /* sizeof byte count */ +

			       get_bcc(&pSMBr->hdr) + (char *)&pSMBr->ByteCount;



			struct reparse_data *reparse_buf =

						(struct reparse_data *)

						((char *)&pSMBr->hdr.Protocol

								 + data_offset);

			if ((char *)reparse_buf >= end_of_smb) {

	if (!data_count || (data_count > 2048)) {

		rc = -EIO;

		cifs_dbg(FYI, "Invalid return data count on get reparse info ioctl\n");

		goto qreparse_out;

	}

			if ((reparse_buf->LinkNamesBuf +

				reparse_buf->TargetNameOffset +

				reparse_buf->TargetNameLen) > end_of_smb) {

				cifs_dbg(FYI, "reparse buf beyond SMB\n");

	end_of_smb = 2 + get_bcc(&pSMBr->hdr) + (char *)&pSMBr->ByteCount;

	reparse_buf = (struct reparse_data *)

				((char *)&pSMBr->hdr.Protocol + data_offset);

	if ((char *)reparse_buf >= end_of_smb) {

		rc = -EIO;

		goto qreparse_out;

	}



			if (pSMBr->hdr.Flags2 & SMBFLG2_UNICODE) {

				cifs_from_ucs2(symlinkinfo, (__le16 *)

						(reparse_buf->LinkNamesBuf +

						reparse_buf->TargetNameOffset),

						buflen,

						reparse_buf->TargetNameLen,

						nls_codepage, 0);

			} else { /* ASCII names */

				strncpy(symlinkinfo,

					reparse_buf->LinkNamesBuf +

					reparse_buf->TargetNameOffset,

					min_t(const int, buflen,

					   reparse_buf->TargetNameLen));

			}

		} else {

	if ((reparse_buf->PathBuffer + reparse_buf->PrintNameOffset +

				reparse_buf->PrintNameLength) > end_of_smb) {

		cifs_dbg(FYI, "reparse buf beyond SMB\n");

		rc = -EIO;

			cifs_dbg(FYI, "Invalid return data count on get reparse info ioctl\n");

		}

		symlinkinfo[buflen] = 0; /* just in case so the caller

					does not go off the end of the buffer */

		cifs_dbg(FYI, "readlink result - %s\n", symlinkinfo);

		goto qreparse_out;

	}

	sub_start = reparse_buf->SubstituteNameOffset + reparse_buf->PathBuffer;

	sub_len = reparse_buf->SubstituteNameLength;

	if (pSMBr->hdr.Flags2 & SMBFLG2_UNICODE)

		is_unicode = true;

	else

		is_unicode = false;



	/* BB FIXME investigate remapping reserved chars here */

	*symlinkinfo = cifs_strndup_from_utf16(sub_start, sub_len, is_unicode,

					       nls_codepage);

	if (!*symlinkinfo)

		rc = -ENOMEM;

qreparse_out:

	cifs_buf_release(pSMB);



	/* Note: On -EAGAIN error only caller can retry on handle based calls

		since file handle passed in no longer valid */



	/*

	 * Note: On -EAGAIN error only caller can retry on handle based calls

	 * since file handle passed in no longer valid.

	 */

	return rc;

}

#endif /* CIFS_SYMLINK_EXPERIMENTAL */ /* BB temporarily unused */



#ifdef CONFIG_CIFS_POSIX

fs/cifs/smb1ops.c

+32 −0
Original line number Diff line number Diff line
@@ -881,6 +881,37 @@ cifs_mand_lock(const unsigned int xid, struct cifsFileInfo *cfile, __u64 offset, 
			   (__u8)type, wait, 0);

}



static int

cifs_query_symlink(const unsigned int xid, struct cifs_tcon *tcon,

		   const char *full_path, char **target_path,

		   struct cifs_sb_info *cifs_sb)

{

	int rc;

	int oplock = 0;

	__u16 netfid;



	cifs_dbg(FYI, "%s: path: %s\n", __func__, full_path);



	rc = CIFSSMBOpen(xid, tcon, full_path, FILE_OPEN,

			 FILE_READ_ATTRIBUTES, OPEN_REPARSE_POINT, &netfid,

			 &oplock, NULL, cifs_sb->local_nls,

			 cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR);

	if (rc)

		return rc;



	rc = CIFSSMBQuerySymLink(xid, tcon, netfid, target_path,

				 cifs_sb->local_nls);

	if (rc) {

		CIFSSMBClose(xid, tcon, netfid);

		return rc;

	}



	convert_delimiter(*target_path, '/');

	CIFSSMBClose(xid, tcon, netfid);

	cifs_dbg(FYI, "%s: target path: %s\n", __func__, *target_path);

	return rc;

}



struct smb_version_operations smb1_operations = {

	.send_cancel = send_nt_cancel,

	.compare_fids = cifs_compare_fids,
@@ -927,6 +958,7 @@ struct smb_version_operations smb1_operations = { 
	.rename_pending_delete = cifs_rename_pending_delete,

	.rename = CIFSSMBRename,

	.create_hardlink = CIFSCreateHardLink,

	.query_symlink = cifs_query_symlink,

	.open = cifs_open_file,

	.set_fid = cifs_set_fid,

	.close = cifs_close_file,