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CIFS: Implement follow_link for nounix CIFS mounts

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by using a query reparse ioctl request.

Acked-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Pavel Shilovsky <pshilovsky@samba.org>
Signed-off-by: Steve French <smfrench@gmail.com>
This commit is contained in:
Pavel Shilovsky
2013-08-14 19:25:22 +04:00
committed by Steve French
parent b42bf88828
commit d244bf2dfb
4 changed files with 93 additions and 72 deletions
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112
fs/cifs/cifssmb.c
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@@ -3067,7 +3067,6 @@ querySymLinkRetry:
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 @@ querySymLinkRetry:
* 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,
const struct nls_table *nls_codepage)
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);
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) {
rc = -EIO;
goto qreparse_out;
}
if ((reparse_buf->LinkNamesBuf +
reparse_buf->TargetNameOffset +
reparse_buf->TargetNameLen) > end_of_smb) {
cifs_dbg(FYI, "reparse buf beyond SMB\n");
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 {
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;
}
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)) {
rc = -EIO;
cifs_dbg(FYI, "Invalid return data count on get reparse info ioctl\n");
goto qreparse_out;
}
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 ((reparse_buf->PathBuffer + reparse_buf->PrintNameOffset +
reparse_buf->PrintNameLength) > end_of_smb) {
cifs_dbg(FYI, "reparse buf beyond SMB\n");
rc = -EIO;
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