Commit c22870ea authored by Steve French's avatar Steve French
Browse files

mfsymlinks support for SMB2.1/SMB3. Part 2 query symlink 

Adds support on SMB2.1 and SMB3 mounts for emulation of symlinks
via the "Minshall/French" symlink format already used for cifs
mounts when mfsymlinks mount option is used (and also used by Apple).
  http://wiki.samba.org/index.php/UNIX_Extensions#Minshall.2BFrench_symlinks


This second patch adds support to query them (recognize them as symlinks
and read them).  Third version of patch makes minor corrections
to error handling.

Signed-off-by: default avatarSteve French <smfrench@gmail.com>
Reviewed-by: default avatarStefan Metzmacher <metze@samba.org>
parent 5ab97578

fs/cifs/link.c

+69 −1
Original line number Diff line number Diff line
@@ -28,7 +28,9 @@ 
#include "cifsproto.h"

#include "cifs_debug.h"

#include "cifs_fs_sb.h"

#ifdef CONFIG_CIFS_SMB2

#include "smb2proto.h"

#endif



/*

 * M-F Symlink Functions - Begin
@@ -401,6 +403,72 @@ cifs_create_mf_symlink(unsigned int xid, struct cifs_tcon *tcon, 
	return rc;

}



/*

 * SMB 2.1/SMB3 Protocol specific functions

 */

#ifdef CONFIG_CIFS_SMB2

int

smb3_query_mf_symlink(unsigned int xid, struct cifs_tcon *tcon,

		      struct cifs_sb_info *cifs_sb, const unsigned char *path,

		      char *pbuf, unsigned int *pbytes_read)

{

	int rc;

	struct cifs_fid fid;

	struct cifs_open_parms oparms;

	struct cifs_io_parms io_parms;

	int buf_type = CIFS_NO_BUFFER;

	__le16 *utf16_path;

	__u8 oplock = SMB2_OPLOCK_LEVEL_II;

	struct smb2_file_all_info *pfile_info = NULL;



	oparms.tcon = tcon;

	oparms.cifs_sb = cifs_sb;

	oparms.desired_access = GENERIC_READ;

	oparms.create_options = CREATE_NOT_DIR;

	if (backup_cred(cifs_sb))

		oparms.create_options |= CREATE_OPEN_BACKUP_INTENT;

	oparms.disposition = FILE_OPEN;

	oparms.fid = &fid;

	oparms.reconnect = false;



	utf16_path = cifs_convert_path_to_utf16(path, cifs_sb);

	if (utf16_path == NULL)

		return -ENOMEM;



	pfile_info = kzalloc(sizeof(struct smb2_file_all_info) + PATH_MAX * 2,

			     GFP_KERNEL);



	if (pfile_info == NULL) {

		kfree(utf16_path);

		return  -ENOMEM;

	}



	rc = SMB2_open(xid, &oparms, utf16_path, &oplock, pfile_info, NULL);

	if (rc)

		goto qmf_out_open_fail;



	if (pfile_info->EndOfFile != cpu_to_le64(CIFS_MF_SYMLINK_FILE_SIZE)) {

		/* it's not a symlink */

		rc = -ENOENT; /* Is there a better rc to return? */

		goto qmf_out;

	}



	io_parms.netfid = fid.netfid;

	io_parms.pid = current->tgid;

	io_parms.tcon = tcon;

	io_parms.offset = 0;

	io_parms.length = CIFS_MF_SYMLINK_FILE_SIZE;

	io_parms.persistent_fid = fid.persistent_fid;

	io_parms.volatile_fid = fid.volatile_fid;

	rc = SMB2_read(xid, &io_parms, pbytes_read, &pbuf, &buf_type);

qmf_out:

	SMB2_close(xid, tcon, fid.persistent_fid, fid.volatile_fid);

qmf_out_open_fail:

	kfree(utf16_path);

	kfree(pfile_info);

	return rc;

}



int

smb3_create_mf_symlink(unsigned int xid, struct cifs_tcon *tcon,

		       struct cifs_sb_info *cifs_sb, const unsigned char *path,
@@ -461,7 +529,7 @@ smb3_create_mf_symlink(unsigned int xid, struct cifs_tcon *tcon, 
	kfree(utf16_path);

	return rc;

}



#endif /* CONFIG_CIFS_SMB2 */



/*

 * M-F Symlink Functions - End

fs/cifs/smb2ops.c

+2 −0
Original line number Diff line number Diff line
@@ -1452,6 +1452,7 @@ struct smb_version_operations smb21_operations = { 
	.rename = smb2_rename_path,

	.create_hardlink = smb2_create_hardlink,

	.query_symlink = smb2_query_symlink,

	.query_mf_symlink = smb3_query_mf_symlink,

	.create_mf_symlink = smb3_create_mf_symlink,

	.open = smb2_open_file,

	.set_fid = smb2_set_fid,
@@ -1532,6 +1533,7 @@ struct smb_version_operations smb30_operations = { 
	.rename = smb2_rename_path,

	.create_hardlink = smb2_create_hardlink,

	.query_symlink = smb2_query_symlink,

	.query_mf_symlink = smb3_query_mf_symlink,

	.create_mf_symlink = smb3_create_mf_symlink,

	.open = smb2_open_file,

	.set_fid = smb2_set_fid,

fs/cifs/smb2proto.h

+4 −0
Original line number Diff line number Diff line
@@ -85,6 +85,10 @@ extern int smb2_create_hardlink(const unsigned int xid, struct cifs_tcon *tcon, 
extern int smb3_create_mf_symlink(unsigned int xid, struct cifs_tcon *tcon,

			struct cifs_sb_info *cifs_sb, const unsigned char *path,

			char *pbuf, unsigned int *pbytes_written);

extern int smb3_query_mf_symlink(unsigned int xid, struct cifs_tcon *tcon,

			  struct cifs_sb_info *cifs_sb,

			  const unsigned char *path, char *pbuf,

			  unsigned int *pbytes_read);

extern int smb2_open_file(const unsigned int xid,

			  struct cifs_open_parms *oparms,

			  __u32 *oplock, FILE_ALL_INFO *buf);

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