[CIFS] Support for Minshall+French symlinks

[CIFS] Support for Minshall+French symlinks

[Stefan Metzmacher]

Hi Steve,

The following patchset adds support Minshall+French symlinks for Linux.
See http://wiki.samba.org/index.php/UNIX_Extensions#Minshall.2BFrench_symlinks

I've added a new mount option 'mfsymlinks', which is off by default.

If the option is pass to a mount, Minshall+French symlinks will be used
to support symlinks for the local client.

This is compatible with the Darwin implementation.

Can you review this patches? It would be wonderful if they would endup
in Linux 2.6.36.

metze

[PATCH 1/8] cifs: add "mfsymlinks" mount option

[Stefan Metzmacher]

This is the start for an implementation of "Minshall+French Symlinks"
(see http://wiki.samba.org/index.php/UNIX_Extensions#Minshall.2BFrench_symlinks).

Signed-off-by: Stefan Metzmacher <metze-eUNUBHrolfbYtjvyW6yDsg@public.gmane.org>
---
 fs/cifs/README       |    5 +++++
 fs/cifs/cifs_fs_sb.h |    1 +
 fs/cifs/cifsfs.c     |    2 ++
 fs/cifs/connect.c    |   11 +++++++++++
 4 files changed, 19 insertions(+), 0 deletions(-)

diff --git a/fs/cifs/README b/fs/cifs/README
index a727b7c..228c239 100644
--- a/fs/cifs/README
+++ b/fs/cifs/README
@@ -517,6 +517,11 @@ A partial list of the supported mount options follows:
 		SFU does).  In the future the bottom 9 bits of the
 		mode also will be emulated using queries of the security
 		descriptor (ACL).
+ mfsymlinks     Enable support for Minshall+French symlinks
+		(see http://wiki.samba.org/index.php/UNIX_Extensions#Minshall.2BFrench_symlinks)
+		This option is ignored when specified together with the
+		'sfu' option. Minshall+French symlinks are used event if
+		the server supports the CIFS Unix Extensions.
  sign           Must use packet signing (helps avoid unwanted data modification
 		by intermediate systems in the route).  Note that signing
 		does not work with lanman or plaintext authentication.
diff --git a/fs/cifs/cifs_fs_sb.h b/fs/cifs/cifs_fs_sb.h
index 9e77145..7fde529 100644
--- a/fs/cifs/cifs_fs_sb.h
+++ b/fs/cifs/cifs_fs_sb.h
@@ -36,6 +36,7 @@
 #define CIFS_MOUNT_NOPOSIXBRL   0x2000 /* mandatory not posix byte range lock */
 #define CIFS_MOUNT_NOSSYNC      0x4000 /* don't do slow SMBflush on every sync*/
 #define CIFS_MOUNT_FSCACHE	0x8000 /* local caching enabled */
+#define CIFS_MOUNT_MF_SYMLINKS	0x10000 /* Minshall+French Symlinks enabled */
 
 struct cifs_sb_info {
 	struct cifsTconInfo *tcon;	/* primary mount */
diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index 8a2cf12..ec48c96 100644
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -421,6 +421,8 @@ cifs_show_options(struct seq_file *s, struct vfsmount *m)
 		seq_printf(s, ",dynperm");
 	if (m->mnt_sb->s_flags & MS_POSIXACL)
 		seq_printf(s, ",acl");
+	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS)
+		seq_printf(s, ",mfsymlinks");
 
 	seq_printf(s, ",rsize=%d", cifs_sb->rsize);
 	seq_printf(s, ",wsize=%d", cifs_sb->wsize);
diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 2a43a0a..b3b8752 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -100,6 +100,7 @@ struct smb_vol {
 	bool noautotune:1;
 	bool nostrictsync:1; /* do not force expensive SMBflush on every sync */
 	bool fsc:1;	/* enable fscache */
+	bool mfsymlinks:1; /* use Minshall+French Symlinks */
 	unsigned int rsize;
 	unsigned int wsize;
 	bool sockopt_tcp_nodelay:1;
@@ -1343,6 +1344,8 @@ cifs_parse_mount_options(char *options, const char *devname,
 				"/proc/fs/cifs/LookupCacheEnabled to 0\n");
 		} else if (strnicmp(data, "fsc", 3) == 0) {
 			vol->fsc = true;
+		} else if (strnicmp(data, "mfsymlinks", 22) == 0) {
+			vol->mfsymlinks = true;
 		} else
 			printk(KERN_WARNING "CIFS: Unknown mount option %s\n",
 						data);
@@ -2481,6 +2484,14 @@ static void setup_cifs_sb(struct smb_vol *pvolume_info,
 		cFYI(1, "mounting share using direct i/o");
 		cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_DIRECT_IO;
 	}
+	if (pvolume_info->mfsymlinks) {
+		if (pvolume_info->sfu_emul) {
+			cERROR(1,  "mount option mfsymlinks ignored if sfu "
+				   "mount option is used");
+		} else {
+			cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_MF_SYMLINKS;
+		}
+	}
 
 	if ((pvolume_info->cifs_acl) && (pvolume_info->dynperm))
 		cERROR(1, "mount option dynperm ignored if cifsacl "
-- 
1.7.0.4

Re: [PATCH 1/8] cifs: add "mfsymlinks" mount option

[Suresh Jayaraman]

On 08/03/2010 08:35 PM, Stefan Metzmacher wrote:
> This is the start for an implementation of "Minshall+French Symlinks"
> (see http://wiki.samba.org/index.php/UNIX_Extensions#Minshall.2BFrench_symlinks).
> 
> Signed-off-by: Stefan Metzmacher <metze-eUNUBHrolfbYtjvyW6yDsg@public.gmane.org>
> ---
>  fs/cifs/README       |    5 +++++
>  fs/cifs/cifs_fs_sb.h |    1 +
>  fs/cifs/cifsfs.c     |    2 ++
>  fs/cifs/connect.c    |   11 +++++++++++
>  4 files changed, 19 insertions(+), 0 deletions(-)
> 
> diff --git a/fs/cifs/README b/fs/cifs/README
> index a727b7c..228c239 100644
> --- a/fs/cifs/README
> +++ b/fs/cifs/README
> @@ -517,6 +517,11 @@ A partial list of the supported mount options follows:
>  		SFU does).  In the future the bottom 9 bits of the
>  		mode also will be emulated using queries of the security
>  		descriptor (ACL).
> + mfsymlinks     Enable support for Minshall+French symlinks
> +		(see http://wiki.samba.org/index.php/UNIX_Extensions#Minshall.2BFrench_symlinks)
> +		This option is ignored when specified together with the
> +		'sfu' option. Minshall+French symlinks are used event if

nit..  Did you mean "even" here?                               ^^^^

> +		the server supports the CIFS Unix Extensions.
>   sign           Must use packet signing (helps avoid unwanted data modification
>  		by intermediate systems in the route).  Note that signing
>  		does not work with lanman or plaintext authentication.
> diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
> index 2a43a0a..b3b8752 100644
> --- a/fs/cifs/connect.c
> +++ b/fs/cifs/connect.c
> @@ -100,6 +100,7 @@ struct smb_vol {
>  	bool noautotune:1;
>  	bool nostrictsync:1; /* do not force expensive SMBflush on every sync */
>  	bool fsc:1;	/* enable fscache */
> +	bool mfsymlinks:1; /* use Minshall+French Symlinks */
>  	unsigned int rsize;
>  	unsigned int wsize;
>  	bool sockopt_tcp_nodelay:1;
> @@ -1343,6 +1344,8 @@ cifs_parse_mount_options(char *options, const char *devname,
>  				"/proc/fs/cifs/LookupCacheEnabled to 0\n");
>  		} else if (strnicmp(data, "fsc", 3) == 0) {
>  			vol->fsc = true;
> +		} else if (strnicmp(data, "mfsymlinks", 22) == 0) {
				
 Why 22 here?


Thanks,


-- 
Suresh Jayaraman

[PATCH 2/8] cifs: add CIFSCreateMFSymLink() and CIFSQueryMFSymLink() as stubs

[Stefan Metzmacher]

Signed-off-by: Stefan Metzmacher <metze-eUNUBHrolfbYtjvyW6yDsg@public.gmane.org>
---
 fs/cifs/link.c |   34 ++++++++++++++++++++++++++++++----
 1 files changed, 30 insertions(+), 4 deletions(-)

diff --git a/fs/cifs/link.c b/fs/cifs/link.c
index 473ca80..2358a5f 100644
--- a/fs/cifs/link.c
+++ b/fs/cifs/link.c
@@ -29,6 +29,24 @@
 #include "cifs_debug.h"
 #include "cifs_fs_sb.h"
 
+static int
+CIFSCreateMFSymLink(const int xid, struct cifsTconInfo *tcon,
+		    const char *fromName, const char *toName,
+		    const struct nls_table *nls_codepage)
+{
+	int rc = -EOPNOTSUPP;
+	return rc;
+}
+
+static int
+CIFSQueryMFSymLink(const int xid, struct cifsTconInfo *tcon,
+		   const unsigned char *searchName, char **symlinkinfo,
+		   const struct nls_table *nls_codepage)
+{
+	int rc = -EOPNOTSUPP;
+	return rc;
+}
+
 int
 cifs_hardlink(struct dentry *old_file, struct inode *inode,
 	      struct dentry *direntry)
@@ -130,7 +148,8 @@ cifs_follow_link(struct dentry *direntry, struct nameidata *nd)
 	 * but there doesn't seem to be any harm in allowing the client to
 	 * read them.
 	 */
-	if (!(tcon->ses->capabilities & CAP_UNIX)) {
+	if (!(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS)
+	    && !(tcon->ses->capabilities & CAP_UNIX)) {
 		rc = -EACCES;
 		goto out;
 	}
@@ -141,8 +160,12 @@ cifs_follow_link(struct dentry *direntry, struct nameidata *nd)
 
 	cFYI(1, "Full path: %s inode = 0x%p", full_path, inode);
 
-	rc = CIFSSMBUnixQuerySymLink(xid, tcon, full_path, &target_path,
-				     cifs_sb->local_nls);
+	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS)
+		rc = CIFSQueryMFSymLink(xid, tcon, full_path, &target_path,
+					cifs_sb->local_nls);
+	else
+		rc = CIFSSMBUnixQuerySymLink(xid, tcon, full_path, &target_path,
+					     cifs_sb->local_nls);
 	kfree(full_path);
 out:
 	if (rc != 0) {
@@ -182,7 +205,10 @@ cifs_symlink(struct inode *inode, struct dentry *direntry, const char *symname)
 	cFYI(1, "symname is %s", symname);
 
 	/* BB what if DFS and this volume is on different share? BB */
-	if (pTcon->unix_ext)
+	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS)
+		rc = CIFSCreateMFSymLink(xid, pTcon, full_path, symname,
+					 cifs_sb->local_nls);
+	else if (pTcon->unix_ext)
 		rc = CIFSUnixCreateSymLink(xid, pTcon, full_path, symname,
 					   cifs_sb->local_nls);
 	/* else
-- 
1.7.0.4

Re: [PATCH 2/8] cifs: add CIFSCreateMFSymLink() and CIFSQueryMFSymLink() as stubs

[Suresh Jayaraman]

On 08/03/2010 08:35 PM, Stefan Metzmacher wrote:
> Signed-off-by: Stefan Metzmacher <metze-eUNUBHrolfbYtjvyW6yDsg@public.gmane.org>
> ---
>  fs/cifs/link.c |   34 ++++++++++++++++++++++++++++++----
>  1 files changed, 30 insertions(+), 4 deletions(-)
> 
> diff --git a/fs/cifs/link.c b/fs/cifs/link.c
> index 473ca80..2358a5f 100644
> --- a/fs/cifs/link.c
> +++ b/fs/cifs/link.c
> @@ -29,6 +29,24 @@
>  #include "cifs_debug.h"
>  #include "cifs_fs_sb.h"
>  
> +static int
> +CIFSCreateMFSymLink(const int xid, struct cifsTconInfo *tcon,
> +		    const char *fromName, const char *toName,
> +		    const struct nls_table *nls_codepage)
> +{
> +	int rc = -EOPNOTSUPP;
> +	return rc;
> +}
> +
> +static int
> +CIFSQueryMFSymLink(const int xid, struct cifsTconInfo *tcon,
> +		   const unsigned char *searchName, char **symlinkinfo,
> +		   const struct nls_table *nls_codepage)
> +{
> +	int rc = -EOPNOTSUPP;
> +	return rc;
> +}

Perhaps these two should be added to cifssmb.c because that is where the
other related functions are defined?

Thanks,

-- 
Suresh Jayaraman

[PATCH 3/8] cifs: add CIFSCheckMFSymlink() as stub

[Stefan Metzmacher]

Signed-off-by: Stefan Metzmacher <metze-eUNUBHrolfbYtjvyW6yDsg@public.gmane.org>
---
 fs/cifs/cifsproto.h |    3 +++
 fs/cifs/inode.c     |    7 +++++++
 fs/cifs/link.c      |    8 ++++++++
 3 files changed, 18 insertions(+), 0 deletions(-)

diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h
index 2eaebbd..e94e095 100644
--- a/fs/cifs/cifsproto.h
+++ b/fs/cifs/cifsproto.h
@@ -409,4 +409,7 @@ extern int CIFSSMBSetPosixACL(const int xid, struct cifsTconInfo *tcon,
 extern int CIFSGetExtAttr(const int xid, struct cifsTconInfo *tcon,
 			const int netfid, __u64 *pExtAttrBits, __u64 *pMask);
 extern void cifs_autodisable_serverino(struct cifs_sb_info *cifs_sb);
+extern int CIFSCheckMFSymlink(struct cifs_fattr *fattr,
+		const unsigned char *path,
+		struct cifs_sb_info *cifs_sb, int xid);
 #endif			/* _CIFSPROTO_H */
diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c
index a15b3a9..c4121de 100644
--- a/fs/cifs/inode.c
+++ b/fs/cifs/inode.c
@@ -661,6 +661,13 @@ int cifs_get_inode_info(struct inode **pinode,
 	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_UNX_EMUL)
 		cifs_sfu_mode(&fattr, full_path, cifs_sb, xid);
 
+	/* query for SFU type info if supported and needed */
+	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS) {
+		tmprc = CIFSCheckMFSymlink(&fattr, full_path, cifs_sb, xid);
+		if (tmprc)
+			cFYI(1, "CIFSCheckMFSymlink: %d", tmprc);
+	}
+
 	if (!*pinode) {
 		*pinode = cifs_iget(sb, &fattr);
 		if (!*pinode)
diff --git a/fs/cifs/link.c b/fs/cifs/link.c
index 2358a5f..985373c 100644
--- a/fs/cifs/link.c
+++ b/fs/cifs/link.c
@@ -48,6 +48,14 @@ CIFSQueryMFSymLink(const int xid, struct cifsTconInfo *tcon,
 }
 
 int
+CIFSCheckMFSymlink(struct cifs_fattr *fattr,
+		   const unsigned char *path,
+		   struct cifs_sb_info *cifs_sb, int xid)
+{
+	return 0;
+}
+
+int
 cifs_hardlink(struct dentry *old_file, struct inode *inode,
 	      struct dentry *direntry)
 {
-- 
1.7.0.4

[PATCH 4/8] cifs: implement CIFSParseMFSymlink()

[Stefan Metzmacher]

Signed-off-by: Stefan Metzmacher <metze-eUNUBHrolfbYtjvyW6yDsg@public.gmane.org>
---
 fs/cifs/link.c |   61 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 61 insertions(+), 0 deletions(-)

diff --git a/fs/cifs/link.c b/fs/cifs/link.c
index 985373c..33307b1 100644
--- a/fs/cifs/link.c
+++ b/fs/cifs/link.c
@@ -28,6 +28,67 @@
 #include "cifsproto.h"
 #include "cifs_debug.h"
 #include "cifs_fs_sb.h"
+#include "md5.h"
+
+#define CIFS_MF_SYMLINK_LEN_OFFSET (4+1)
+#define CIFS_MF_SYMLINK_MD5_OFFSET (CIFS_MF_SYMLINK_LEN_OFFSET+(4+1))
+#define CIFS_MF_SYMLINK_LINK_OFFSET (CIFS_MF_SYMLINK_MD5_OFFSET+(32+1))
+#define CIFS_MF_SYMLINK_LINK_MAXLEN (1024)
+#define CIFS_MF_SYMLINK_FILE_SIZE (CIFS_MF_SYMLINK_LINK_OFFSET + CIFS_MF_SYMLINK_LINK_MAXLEN)
+
+#define CIFS_MF_SYMLINK_LEN_FORMAT "XSym\n%04u\n"
+#define CIFS_MF_SYMLINK_MD5_FORMAT \
+	"%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x\n"
+#define CIFS_MF_SYMLINK_MD5_ARGS(md5_hash) \
+	md5_hash[0],  md5_hash[1],  md5_hash[2],  md5_hash[3], \
+	md5_hash[4],  md5_hash[5],  md5_hash[6],  md5_hash[7], \
+	md5_hash[8],  md5_hash[9],  md5_hash[10], md5_hash[11],\
+	md5_hash[12], md5_hash[13], md5_hash[14], md5_hash[15]
+
+static int
+CIFSParseMFSymlink(const u8 *buf,
+		   unsigned int buf_len,
+		   unsigned int *_link_len,
+		   char **_link_str)
+{
+	int rc;
+	unsigned int link_len;
+	const char *md5_str1;
+	const char *link_str;
+	struct MD5Context md5_ctx;
+	u8 md5_hash[16];
+	char md5_str2[34];
+
+	if (buf_len != CIFS_MF_SYMLINK_FILE_SIZE)
+		return -EINVAL;
+
+	md5_str1 = (const char *)&buf[CIFS_MF_SYMLINK_MD5_OFFSET];
+	link_str = (const char *)&buf[CIFS_MF_SYMLINK_LINK_OFFSET];
+
+	rc = sscanf(buf, CIFS_MF_SYMLINK_LEN_FORMAT, &link_len);
+	if (rc != 1)
+		return -EINVAL;
+
+	cifs_MD5_init(&md5_ctx);
+	cifs_MD5_update(&md5_ctx, (const u8 *)link_str, link_len);
+	cifs_MD5_final(md5_hash, &md5_ctx);
+
+	snprintf(md5_str2, sizeof(md5_str2),
+		 CIFS_MF_SYMLINK_MD5_FORMAT,
+		 CIFS_MF_SYMLINK_MD5_ARGS(md5_hash));
+
+	if (strncmp(md5_str1, md5_str2, 17) != 0)
+		return -EINVAL;
+
+	if (_link_str) {
+		*_link_str = kstrndup(link_str, link_len, GFP_KERNEL);
+		if (!*_link_str)
+			return -ENOMEM;
+	}
+
+	*_link_len = link_len;
+	return 0;
+}
 
 static int
 CIFSCreateMFSymLink(const int xid, struct cifsTconInfo *tcon,
-- 
1.7.0.4

[PATCH 5/8] cifs: implement CIFSCheckMFSymlink()

[Stefan Metzmacher]

Signed-off-by: Stefan Metzmacher <metze-eUNUBHrolfbYtjvyW6yDsg@public.gmane.org>
---
 fs/cifs/link.c |   60 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 60 insertions(+), 0 deletions(-)

diff --git a/fs/cifs/link.c b/fs/cifs/link.c
index 33307b1..f7636f9 100644
--- a/fs/cifs/link.c
+++ b/fs/cifs/link.c
@@ -113,6 +113,66 @@ CIFSCheckMFSymlink(struct cifs_fattr *fattr,
 		   const unsigned char *path,
 		   struct cifs_sb_info *cifs_sb, int xid)
 {
+	int rc;
+	int oplock = 0;
+	__u16 netfid = 0;
+	struct cifsTconInfo *pTcon = cifs_sb->tcon;
+	u8 buf[CIFS_MF_SYMLINK_FILE_SIZE];
+	char *pbuf = buf;
+	unsigned int bytes_read = 0;
+	int buf_type = CIFS_NO_BUFFER;
+	unsigned int link_len = 0;
+	FILE_ALL_INFO file_info;
+
+	if (!(fattr->cf_mode & S_IFREG)) {
+		/* it's not a symlink */
+		return 0;
+	}
+
+	if (fattr->cf_eof != CIFS_MF_SYMLINK_FILE_SIZE) {
+		/* it's not a symlink */
+		return 0;
+	}
+
+	rc = CIFSSMBOpen(xid, pTcon, path, FILE_OPEN, GENERIC_READ,
+			 CREATE_NOT_DIR, &netfid, &oplock, &file_info,
+			 cifs_sb->local_nls,
+			 cifs_sb->mnt_cifs_flags &
+				CIFS_MOUNT_MAP_SPECIAL_CHR);
+	if (rc != 0) {
+		return rc;
+	}
+
+	if (file_info.EndOfFile != CIFS_MF_SYMLINK_FILE_SIZE) {
+		CIFSSMBClose(xid, pTcon, netfid);
+		/* it's not a symlink */
+		return 0;
+	}
+
+	/* Read header */
+	rc = CIFSSMBRead(xid, pTcon, netfid,
+			 CIFS_MF_SYMLINK_FILE_SIZE /* length */,
+			 0 /* offset */,
+			 &bytes_read, &pbuf, &buf_type);
+	CIFSSMBClose(xid, pTcon, netfid);
+	if (rc != 0) {
+		return rc;
+	}
+
+	rc = CIFSParseMFSymlink(buf, bytes_read, &link_len, NULL);
+	if (rc == EINVAL) {
+		/* it's not a symlink */
+		return 0;
+	}
+	if (rc != 0) {
+		return rc;
+	}
+
+	/* it is a symlink */
+	fattr->cf_eof = link_len;
+	fattr->cf_mode &= ~S_IFMT;
+	fattr->cf_mode |= S_IFLNK;
+	fattr->cf_dtype = DT_LNK;
 	return 0;
 }
 
-- 
1.7.0.4

[PATCH 6/8] cifs: implement CIFSQueryMFSymLink()

[Stefan Metzmacher]

Signed-off-by: Stefan Metzmacher <metze-eUNUBHrolfbYtjvyW6yDsg@public.gmane.org>
---
 fs/cifs/link.c |   46 ++++++++++++++++++++++++++++++++++++++++++----
 1 files changed, 42 insertions(+), 4 deletions(-)

diff --git a/fs/cifs/link.c b/fs/cifs/link.c
index f7636f9..77f5a40 100644
--- a/fs/cifs/link.c
+++ b/fs/cifs/link.c
@@ -102,10 +102,46 @@ CIFSCreateMFSymLink(const int xid, struct cifsTconInfo *tcon,
 static int
 CIFSQueryMFSymLink(const int xid, struct cifsTconInfo *tcon,
 		   const unsigned char *searchName, char **symlinkinfo,
-		   const struct nls_table *nls_codepage)
+		   const struct nls_table *nls_codepage, int remap)
 {
-	int rc = -EOPNOTSUPP;
-	return rc;
+	int rc;
+	int oplock = 0;
+	__u16 netfid = 0;
+	u8 buf[CIFS_MF_SYMLINK_FILE_SIZE];
+	char *pbuf = buf;
+	unsigned int bytes_read = 0;
+	int buf_type = CIFS_NO_BUFFER;
+	unsigned int link_len = 0;
+	FILE_ALL_INFO file_info;
+
+	rc = CIFSSMBOpen(xid, tcon, searchName, FILE_OPEN, GENERIC_READ,
+			 CREATE_NOT_DIR, &netfid, &oplock, &file_info,
+			 nls_codepage, remap);
+	if (rc != 0) {
+		return rc;
+	}
+
+	if (file_info.EndOfFile != CIFS_MF_SYMLINK_FILE_SIZE) {
+		CIFSSMBClose(xid, tcon, netfid);
+		/* it's not a symlink */
+		return -EINVAL;
+	}
+
+	rc = CIFSSMBRead(xid, tcon, netfid,
+			 CIFS_MF_SYMLINK_FILE_SIZE /* length */,
+			 0 /* offset */,
+			 &bytes_read, &pbuf, &buf_type);
+	CIFSSMBClose(xid, tcon, netfid);
+	if (rc != 0) {
+		return rc;
+	}
+
+	rc = CIFSParseMFSymlink(buf, bytes_read, &link_len, symlinkinfo);
+	if (rc != 0) {
+		return rc;
+	}
+
+	return 0;
 }
 
 int
@@ -291,7 +327,9 @@ cifs_follow_link(struct dentry *direntry, struct nameidata *nd)
 
 	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS)
 		rc = CIFSQueryMFSymLink(xid, tcon, full_path, &target_path,
-					cifs_sb->local_nls);
+					cifs_sb->local_nls,
+					cifs_sb->mnt_cifs_flags &
+						CIFS_MOUNT_MAP_SPECIAL_CHR);
 	else
 		rc = CIFSSMBUnixQuerySymLink(xid, tcon, full_path, &target_path,
 					     cifs_sb->local_nls);
-- 
1.7.0.4

Re: [PATCH 6/8] cifs: implement CIFSQueryMFSymLink()

[Jeff Layton]

On Tue,  3 Aug 2010 17:05:58 +0200
Stefan Metzmacher <metze-eUNUBHrolfbYtjvyW6yDsg@public.gmane.org> wrote:

> Signed-off-by: Stefan Metzmacher <metze-eUNUBHrolfbYtjvyW6yDsg@public.gmane.org>
> ---
>  fs/cifs/link.c |   46 ++++++++++++++++++++++++++++++++++++++++++----
>  1 files changed, 42 insertions(+), 4 deletions(-)
> 
> diff --git a/fs/cifs/link.c b/fs/cifs/link.c
> index f7636f9..77f5a40 100644
> --- a/fs/cifs/link.c
> +++ b/fs/cifs/link.c
> @@ -102,10 +102,46 @@ CIFSCreateMFSymLink(const int xid, struct cifsTconInfo *tcon,
>  static int
>  CIFSQueryMFSymLink(const int xid, struct cifsTconInfo *tcon,
>  		   const unsigned char *searchName, char **symlinkinfo,
> -		   const struct nls_table *nls_codepage)
> +		   const struct nls_table *nls_codepage, int remap)
>  {
> -	int rc = -EOPNOTSUPP;
> -	return rc;
> +	int rc;
> +	int oplock = 0;
> +	__u16 netfid = 0;
> +	u8 buf[CIFS_MF_SYMLINK_FILE_SIZE];
	^^^^
	as noted before, you don't want to allocate these big buffers on the stack

> +	char *pbuf = buf;
> +	unsigned int bytes_read = 0;
> +	int buf_type = CIFS_NO_BUFFER;
> +	unsigned int link_len = 0;
> +	FILE_ALL_INFO file_info;
> +
> +	rc = CIFSSMBOpen(xid, tcon, searchName, FILE_OPEN, GENERIC_READ,
> +			 CREATE_NOT_DIR, &netfid, &oplock, &file_info,
> +			 nls_codepage, remap);
> +	if (rc != 0) {
> +		return rc;
> +	}
> +
	In general, kernel coding style leaves out braces when the
	inside of an if block is a single statement. IOW, this should
	read:

	if (rc != 0)
		return rc;

> +	if (file_info.EndOfFile != CIFS_MF_SYMLINK_FILE_SIZE) {
> +		CIFSSMBClose(xid, tcon, netfid);
> +		/* it's not a symlink */
> +		return -EINVAL;
> +	}
> +
> +	rc = CIFSSMBRead(xid, tcon, netfid,
> +			 CIFS_MF_SYMLINK_FILE_SIZE /* length */,
> +			 0 /* offset */,
> +			 &bytes_read, &pbuf, &buf_type);
> +	CIFSSMBClose(xid, tcon, netfid);
> +	if (rc != 0) {
> +		return rc;
> +	}
> +
> +	rc = CIFSParseMFSymlink(buf, bytes_read, &link_len, symlinkinfo);
> +	if (rc != 0) {
> +		return rc;
> +	}
> +
> +	return 0;
>  }
>  
>  int
> @@ -291,7 +327,9 @@ cifs_follow_link(struct dentry *direntry, struct nameidata *nd)
>  
>  	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS)
>  		rc = CIFSQueryMFSymLink(xid, tcon, full_path, &target_path,
> -					cifs_sb->local_nls);
> +					cifs_sb->local_nls,
> +					cifs_sb->mnt_cifs_flags &
> +						CIFS_MOUNT_MAP_SPECIAL_CHR);
>  	else
>  		rc = CIFSSMBUnixQuerySymLink(xid, tcon, full_path, &target_path,
>  					     cifs_sb->local_nls);


-- 
Jeff Layton <jlayton-eUNUBHrolfbYtjvyW6yDsg@public.gmane.org>

[PATCH 7/8] cifs: implement CIFSFormatMFSymlink()

[Stefan Metzmacher]

Signed-off-by: Stefan Metzmacher <metze-eUNUBHrolfbYtjvyW6yDsg@public.gmane.org>
---
 fs/cifs/link.c |   42 ++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 42 insertions(+), 0 deletions(-)

diff --git a/fs/cifs/link.c b/fs/cifs/link.c
index 77f5a40..b281d26 100644
--- a/fs/cifs/link.c
+++ b/fs/cifs/link.c
@@ -91,6 +91,48 @@ CIFSParseMFSymlink(const u8 *buf,
 }
 
 static int
+CIFSFormatMFSymlink(u8 *buf, unsigned int buf_len, const char *link_str)
+{
+	unsigned int link_len;
+	unsigned int ofs;
+	struct MD5Context md5_ctx;
+	u8 md5_hash[16];
+
+	if (buf_len != CIFS_MF_SYMLINK_FILE_SIZE)
+		return -EINVAL;
+
+	link_len = strlen(link_str);
+
+	if (link_len > CIFS_MF_SYMLINK_LINK_MAXLEN)
+		return -ENAMETOOLONG;
+
+	cifs_MD5_init(&md5_ctx);
+	cifs_MD5_update(&md5_ctx, (const u8 *)link_str, link_len);
+	cifs_MD5_final(md5_hash, &md5_ctx);
+
+	snprintf(buf, buf_len,
+		 CIFS_MF_SYMLINK_LEN_FORMAT CIFS_MF_SYMLINK_MD5_FORMAT,
+		 link_len,
+		 CIFS_MF_SYMLINK_MD5_ARGS(md5_hash));
+
+	ofs = CIFS_MF_SYMLINK_LINK_OFFSET;
+	memcpy(buf + ofs, link_str, link_len);
+
+	ofs += link_len;
+	if (ofs < CIFS_MF_SYMLINK_FILE_SIZE) {
+		buf[ofs] = '\n';
+		ofs++;
+	}
+
+	while (ofs < CIFS_MF_SYMLINK_FILE_SIZE) {
+		buf[ofs] = ' ';
+		ofs++;
+	}
+
+	return 0;
+}
+
+static int
 CIFSCreateMFSymLink(const int xid, struct cifsTconInfo *tcon,
 		    const char *fromName, const char *toName,
 		    const struct nls_table *nls_codepage)
-- 
1.7.0.4

[PATCH 8/8] cifs: implement CIFSCreateMFSymLink()

[Stefan Metzmacher]

Signed-off-by: Stefan Metzmacher <metze-eUNUBHrolfbYtjvyW6yDsg@public.gmane.org>
---
 fs/cifs/link.c |   39 +++++++++++++++++++++++++++++++++++----
 1 files changed, 35 insertions(+), 4 deletions(-)

diff --git a/fs/cifs/link.c b/fs/cifs/link.c
index b281d26..93d2dfd 100644
--- a/fs/cifs/link.c
+++ b/fs/cifs/link.c
@@ -135,10 +135,39 @@ CIFSFormatMFSymlink(u8 *buf, unsigned int buf_len, const char *link_str)
 static int
 CIFSCreateMFSymLink(const int xid, struct cifsTconInfo *tcon,
 		    const char *fromName, const char *toName,
-		    const struct nls_table *nls_codepage)
+		    const struct nls_table *nls_codepage, int remap)
 {
-	int rc = -EOPNOTSUPP;
-	return rc;
+	int rc;
+	int oplock = 0;
+	__u16 netfid = 0;
+	u8 buf[CIFS_MF_SYMLINK_FILE_SIZE];
+	unsigned int bytes_written = 0;
+
+	rc = CIFSFormatMFSymlink(buf, sizeof(buf), toName);
+	if (rc != 0) {
+		return rc;
+	}
+
+	rc = CIFSSMBOpen(xid, tcon, fromName, FILE_CREATE, GENERIC_WRITE,
+			 CREATE_NOT_DIR, &netfid, &oplock, NULL,
+			 nls_codepage, remap);
+	if (rc != 0) {
+		return rc;
+	}
+
+	rc = CIFSSMBWrite(xid, tcon, netfid,
+			  sizeof(buf) /* length */,
+			  0 /* offset */,
+			  &bytes_written, buf, NULL, 0);
+	CIFSSMBClose(xid, tcon, netfid);
+	if (rc != 0) {
+		return rc;
+	}
+
+	if (bytes_written != sizeof(buf))
+		return -EIO;
+
+	return 0;
 }
 
 static int
@@ -416,7 +445,9 @@ cifs_symlink(struct inode *inode, struct dentry *direntry, const char *symname)
 	/* BB what if DFS and this volume is on different share? BB */
 	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS)
 		rc = CIFSCreateMFSymLink(xid, pTcon, full_path, symname,
-					 cifs_sb->local_nls);
+					 cifs_sb->local_nls,
+					 cifs_sb->mnt_cifs_flags &
+						CIFS_MOUNT_MAP_SPECIAL_CHR);
 	else if (pTcon->unix_ext)
 		rc = CIFSUnixCreateSymLink(xid, pTcon, full_path, symname,
 					   cifs_sb->local_nls);
-- 
1.7.0.4

Re: [PATCH 8/8] cifs: implement CIFSCreateMFSymLink()

[Jeff Layton]

On Tue,  3 Aug 2010 17:06:00 +0200
Stefan Metzmacher <metze-eUNUBHrolfbYtjvyW6yDsg@public.gmane.org> wrote:

> Signed-off-by: Stefan Metzmacher <metze-eUNUBHrolfbYtjvyW6yDsg@public.gmane.org>
> ---
>  fs/cifs/link.c |   39 +++++++++++++++++++++++++++++++++++----
>  1 files changed, 35 insertions(+), 4 deletions(-)
> 
> diff --git a/fs/cifs/link.c b/fs/cifs/link.c
> index b281d26..93d2dfd 100644
> --- a/fs/cifs/link.c
> +++ b/fs/cifs/link.c
> @@ -135,10 +135,39 @@ CIFSFormatMFSymlink(u8 *buf, unsigned int buf_len, const char *link_str)
>  static int
>  CIFSCreateMFSymLink(const int xid, struct cifsTconInfo *tcon,
>  		    const char *fromName, const char *toName,
> -		    const struct nls_table *nls_codepage)
> +		    const struct nls_table *nls_codepage, int remap)
>  {
> -	int rc = -EOPNOTSUPP;
> -	return rc;
> +	int rc;
> +	int oplock = 0;
> +	__u16 netfid = 0;
> +	u8 buf[CIFS_MF_SYMLINK_FILE_SIZE];
	^^^^^^^^^^^^^^
Oof. You really don't want to do this -- allocating this much on the
stack is a good way to get memory corruption. I'd kmalloc this
buffer instead.

> +	unsigned int bytes_written = 0;
> +
> +	rc = CIFSFormatMFSymlink(buf, sizeof(buf), toName);
> +	if (rc != 0) {
> +		return rc;
> +	}
> +
> +	rc = CIFSSMBOpen(xid, tcon, fromName, FILE_CREATE, GENERIC_WRITE,
> +			 CREATE_NOT_DIR, &netfid, &oplock, NULL,
> +			 nls_codepage, remap);
> +	if (rc != 0) {
> +		return rc;
> +	}
> +
> +	rc = CIFSSMBWrite(xid, tcon, netfid,
> +			  sizeof(buf) /* length */,
> +			  0 /* offset */,
> +			  &bytes_written, buf, NULL, 0);
> +	CIFSSMBClose(xid, tcon, netfid);
> +	if (rc != 0) {
> +		return rc;
> +	}
> +
> +	if (bytes_written != sizeof(buf))
> +		return -EIO;
> +
> +	return 0;
>  }
>  
>  static int
> @@ -416,7 +445,9 @@ cifs_symlink(struct inode *inode, struct dentry *direntry, const char *symname)
>  	/* BB what if DFS and this volume is on different share? BB */
>  	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS)
>  		rc = CIFSCreateMFSymLink(xid, pTcon, full_path, symname,
> -					 cifs_sb->local_nls);
> +					 cifs_sb->local_nls,
> +					 cifs_sb->mnt_cifs_flags &
> +						CIFS_MOUNT_MAP_SPECIAL_CHR);
>  	else if (pTcon->unix_ext)
>  		rc = CIFSUnixCreateSymLink(xid, pTcon, full_path, symname,
>  					   cifs_sb->local_nls);


-- 
Jeff Layton <jlayton-eUNUBHrolfbYtjvyW6yDsg@public.gmane.org>

Re: [CIFS] Support for Minshall+French symlinks

[Steve French]

Interesting.

Generally seems like a good idea.

Jeff made two valid review comments already (on the kmalloc vs. stack,
and the kernel coding style) but note that scripts/checkpatch.pl will
catch additional minor coding style things:

stevef@stevef-laptop:~/smb2$ scripts/checkpatch.pl ~/sm1.patch
WARNING: braces {} are not necessary for single statement blocks
#62: FILE: fs/cifs/link.c:120:
+	if (rc != 0) {
+		return rc;
+	}

Could you clean up the things scripts/checkpatch.pl (and sparse
issues, ie "make modules C=1"  -- if any)

On Tue, Aug 3, 2010 at 10:05 AM, Stefan Metzmacher <metze-eUNUBHrolfbYtjvyW6yDsg@public.gmane.org> wrote:
> Hi Steve,
>
> The following patchset adds support Minshall+French symlinks for Linux.
> See http://wiki.samba.org/index.php/UNIX_Extensions#Minshall.2BFrench_symlinks
>
> I've added a new mount option 'mfsymlinks', which is off by default.
>
> If the option is pass to a mount, Minshall+French symlinks will be used
> to support symlinks for the local client.
>
> This is compatible with the Darwin implementation.
>
> Can you review this patches? It would be wonderful if they would endup
> in Linux 2.6.36.
>
> metze
>
>



-- 
Thanks,

Steve

Re: [CIFS] Support for Minshall+French symlinks

[Stefan Metzmacher]

Hi Steve,

here's the updated patchset.

metze

[PATCH 1/8] cifs: add "mfsymlinks" mount option

[Stefan Metzmacher]

This is the start for an implementation of "Minshall+French Symlinks"
(see http://wiki.samba.org/index.php/UNIX_Extensions#Minshall.2BFrench_symlinks).

Signed-off-by: Stefan Metzmacher <metze-eUNUBHrolfbYtjvyW6yDsg@public.gmane.org>
---
 fs/cifs/README       |    5 +++++
 fs/cifs/cifs_fs_sb.h |    1 +
 fs/cifs/cifsfs.c     |    2 ++
 fs/cifs/connect.c    |   11 +++++++++++
 4 files changed, 19 insertions(+), 0 deletions(-)

diff --git a/fs/cifs/README b/fs/cifs/README
index a727b7c..228c239 100644
--- a/fs/cifs/README
+++ b/fs/cifs/README
@@ -517,6 +517,11 @@ A partial list of the supported mount options follows:
 		SFU does).  In the future the bottom 9 bits of the
 		mode also will be emulated using queries of the security
 		descriptor (ACL).
+ mfsymlinks     Enable support for Minshall+French symlinks
+		(see http://wiki.samba.org/index.php/UNIX_Extensions#Minshall.2BFrench_symlinks)
+		This option is ignored when specified together with the
+		'sfu' option. Minshall+French symlinks are used event if
+		the server supports the CIFS Unix Extensions.
  sign           Must use packet signing (helps avoid unwanted data modification
 		by intermediate systems in the route).  Note that signing
 		does not work with lanman or plaintext authentication.
diff --git a/fs/cifs/cifs_fs_sb.h b/fs/cifs/cifs_fs_sb.h
index 9e77145..7fde529 100644
--- a/fs/cifs/cifs_fs_sb.h
+++ b/fs/cifs/cifs_fs_sb.h
@@ -36,6 +36,7 @@
 #define CIFS_MOUNT_NOPOSIXBRL   0x2000 /* mandatory not posix byte range lock */
 #define CIFS_MOUNT_NOSSYNC      0x4000 /* don't do slow SMBflush on every sync*/
 #define CIFS_MOUNT_FSCACHE	0x8000 /* local caching enabled */
+#define CIFS_MOUNT_MF_SYMLINKS	0x10000 /* Minshall+French Symlinks enabled */
 
 struct cifs_sb_info {
 	struct cifsTconInfo *tcon;	/* primary mount */
diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index 8a2cf12..ec48c96 100644
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -421,6 +421,8 @@ cifs_show_options(struct seq_file *s, struct vfsmount *m)
 		seq_printf(s, ",dynperm");
 	if (m->mnt_sb->s_flags & MS_POSIXACL)
 		seq_printf(s, ",acl");
+	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS)
+		seq_printf(s, ",mfsymlinks");
 
 	seq_printf(s, ",rsize=%d", cifs_sb->rsize);
 	seq_printf(s, ",wsize=%d", cifs_sb->wsize);
diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 2a43a0a..b3b8752 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -100,6 +100,7 @@ struct smb_vol {
 	bool noautotune:1;
 	bool nostrictsync:1; /* do not force expensive SMBflush on every sync */
 	bool fsc:1;	/* enable fscache */
+	bool mfsymlinks:1; /* use Minshall+French Symlinks */
 	unsigned int rsize;
 	unsigned int wsize;
 	bool sockopt_tcp_nodelay:1;
@@ -1343,6 +1344,8 @@ cifs_parse_mount_options(char *options, const char *devname,
 				"/proc/fs/cifs/LookupCacheEnabled to 0\n");
 		} else if (strnicmp(data, "fsc", 3) == 0) {
 			vol->fsc = true;
+		} else if (strnicmp(data, "mfsymlinks", 22) == 0) {
+			vol->mfsymlinks = true;
 		} else
 			printk(KERN_WARNING "CIFS: Unknown mount option %s\n",
 						data);
@@ -2481,6 +2484,14 @@ static void setup_cifs_sb(struct smb_vol *pvolume_info,
 		cFYI(1, "mounting share using direct i/o");
 		cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_DIRECT_IO;
 	}
+	if (pvolume_info->mfsymlinks) {
+		if (pvolume_info->sfu_emul) {
+			cERROR(1,  "mount option mfsymlinks ignored if sfu "
+				   "mount option is used");
+		} else {
+			cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_MF_SYMLINKS;
+		}
+	}
 
 	if ((pvolume_info->cifs_acl) && (pvolume_info->dynperm))
 		cERROR(1, "mount option dynperm ignored if cifsacl "
-- 
1.7.0.4

[PATCH 2/8] cifs: add CIFSCreateMFSymLink() and CIFSQueryMFSymLink() as stubs

[Stefan Metzmacher]

Signed-off-by: Stefan Metzmacher <metze-eUNUBHrolfbYtjvyW6yDsg@public.gmane.org>
---
 fs/cifs/link.c |   34 ++++++++++++++++++++++++++++++----
 1 files changed, 30 insertions(+), 4 deletions(-)

diff --git a/fs/cifs/link.c b/fs/cifs/link.c
index 473ca80..2358a5f 100644
--- a/fs/cifs/link.c
+++ b/fs/cifs/link.c
@@ -29,6 +29,24 @@
 #include "cifs_debug.h"
 #include "cifs_fs_sb.h"
 
+static int
+CIFSCreateMFSymLink(const int xid, struct cifsTconInfo *tcon,
+		    const char *fromName, const char *toName,
+		    const struct nls_table *nls_codepage)
+{
+	int rc = -EOPNOTSUPP;
+	return rc;
+}
+
+static int
+CIFSQueryMFSymLink(const int xid, struct cifsTconInfo *tcon,
+		   const unsigned char *searchName, char **symlinkinfo,
+		   const struct nls_table *nls_codepage)
+{
+	int rc = -EOPNOTSUPP;
+	return rc;
+}
+
 int
 cifs_hardlink(struct dentry *old_file, struct inode *inode,
 	      struct dentry *direntry)
@@ -130,7 +148,8 @@ cifs_follow_link(struct dentry *direntry, struct nameidata *nd)
 	 * but there doesn't seem to be any harm in allowing the client to
 	 * read them.
 	 */
-	if (!(tcon->ses->capabilities & CAP_UNIX)) {
+	if (!(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS)
+	    && !(tcon->ses->capabilities & CAP_UNIX)) {
 		rc = -EACCES;
 		goto out;
 	}
@@ -141,8 +160,12 @@ cifs_follow_link(struct dentry *direntry, struct nameidata *nd)
 
 	cFYI(1, "Full path: %s inode = 0x%p", full_path, inode);
 
-	rc = CIFSSMBUnixQuerySymLink(xid, tcon, full_path, &target_path,
-				     cifs_sb->local_nls);
+	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS)
+		rc = CIFSQueryMFSymLink(xid, tcon, full_path, &target_path,
+					cifs_sb->local_nls);
+	else
+		rc = CIFSSMBUnixQuerySymLink(xid, tcon, full_path, &target_path,
+					     cifs_sb->local_nls);
 	kfree(full_path);
 out:
 	if (rc != 0) {
@@ -182,7 +205,10 @@ cifs_symlink(struct inode *inode, struct dentry *direntry, const char *symname)
 	cFYI(1, "symname is %s", symname);
 
 	/* BB what if DFS and this volume is on different share? BB */
-	if (pTcon->unix_ext)
+	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS)
+		rc = CIFSCreateMFSymLink(xid, pTcon, full_path, symname,
+					 cifs_sb->local_nls);
+	else if (pTcon->unix_ext)
 		rc = CIFSUnixCreateSymLink(xid, pTcon, full_path, symname,
 					   cifs_sb->local_nls);
 	/* else
-- 
1.7.0.4

[PATCH 3/8] cifs: add CIFSCheckMFSymlink() as stub

[Stefan Metzmacher]

Signed-off-by: Stefan Metzmacher <metze-eUNUBHrolfbYtjvyW6yDsg@public.gmane.org>
---
 fs/cifs/cifsproto.h |    3 +++
 fs/cifs/inode.c     |    7 +++++++
 fs/cifs/link.c      |    8 ++++++++
 3 files changed, 18 insertions(+), 0 deletions(-)

diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h
index 2eaebbd..e94e095 100644
--- a/fs/cifs/cifsproto.h
+++ b/fs/cifs/cifsproto.h
@@ -409,4 +409,7 @@ extern int CIFSSMBSetPosixACL(const int xid, struct cifsTconInfo *tcon,
 extern int CIFSGetExtAttr(const int xid, struct cifsTconInfo *tcon,
 			const int netfid, __u64 *pExtAttrBits, __u64 *pMask);
 extern void cifs_autodisable_serverino(struct cifs_sb_info *cifs_sb);
+extern int CIFSCheckMFSymlink(struct cifs_fattr *fattr,
+		const unsigned char *path,
+		struct cifs_sb_info *cifs_sb, int xid);
 #endif			/* _CIFSPROTO_H */
diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c
index a15b3a9..c4121de 100644
--- a/fs/cifs/inode.c
+++ b/fs/cifs/inode.c
@@ -661,6 +661,13 @@ int cifs_get_inode_info(struct inode **pinode,
 	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_UNX_EMUL)
 		cifs_sfu_mode(&fattr, full_path, cifs_sb, xid);
 
+	/* query for SFU type info if supported and needed */
+	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS) {
+		tmprc = CIFSCheckMFSymlink(&fattr, full_path, cifs_sb, xid);
+		if (tmprc)
+			cFYI(1, "CIFSCheckMFSymlink: %d", tmprc);
+	}
+
 	if (!*pinode) {
 		*pinode = cifs_iget(sb, &fattr);
 		if (!*pinode)
diff --git a/fs/cifs/link.c b/fs/cifs/link.c
index 2358a5f..985373c 100644
--- a/fs/cifs/link.c
+++ b/fs/cifs/link.c
@@ -48,6 +48,14 @@ CIFSQueryMFSymLink(const int xid, struct cifsTconInfo *tcon,
 }
 
 int
+CIFSCheckMFSymlink(struct cifs_fattr *fattr,
+		   const unsigned char *path,
+		   struct cifs_sb_info *cifs_sb, int xid)
+{
+	return 0;
+}
+
+int
 cifs_hardlink(struct dentry *old_file, struct inode *inode,
 	      struct dentry *direntry)
 {
-- 
1.7.0.4

Re: [PATCH 3/8] cifs: add CIFSCheckMFSymlink() as stub

[Jeff Layton]

On Wed,  4 Aug 2010 16:11:44 +0200
Stefan Metzmacher <metze-eUNUBHrolfbYtjvyW6yDsg@public.gmane.org> wrote:

> Signed-off-by: Stefan Metzmacher <metze-eUNUBHrolfbYtjvyW6yDsg@public.gmane.org>
> ---
>  fs/cifs/cifsproto.h |    3 +++
>  fs/cifs/inode.c     |    7 +++++++
>  fs/cifs/link.c      |    8 ++++++++
>  3 files changed, 18 insertions(+), 0 deletions(-)
> 
> diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h
> index 2eaebbd..e94e095 100644
> --- a/fs/cifs/cifsproto.h
> +++ b/fs/cifs/cifsproto.h
> @@ -409,4 +409,7 @@ extern int CIFSSMBSetPosixACL(const int xid, struct cifsTconInfo *tcon,
>  extern int CIFSGetExtAttr(const int xid, struct cifsTconInfo *tcon,
>  			const int netfid, __u64 *pExtAttrBits, __u64 *pMask);
>  extern void cifs_autodisable_serverino(struct cifs_sb_info *cifs_sb);
> +extern int CIFSCheckMFSymlink(struct cifs_fattr *fattr,
> +		const unsigned char *path,
> +		struct cifs_sb_info *cifs_sb, int xid);
>  #endif			/* _CIFSPROTO_H */
> diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c
> index a15b3a9..c4121de 100644
> --- a/fs/cifs/inode.c
> +++ b/fs/cifs/inode.c
> @@ -661,6 +661,13 @@ int cifs_get_inode_info(struct inode **pinode,
>  	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_UNX_EMUL)
>  		cifs_sfu_mode(&fattr, full_path, cifs_sb, xid);
>  
> +	/* query for SFU type info if supported and needed */
> +	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS) {
> +		tmprc = CIFSCheckMFSymlink(&fattr, full_path, cifs_sb, xid);
> +		if (tmprc)
> +			cFYI(1, "CIFSCheckMFSymlink: %d", tmprc);
> +	}
> +

		^^^^^^^^^^^^^^

This only seems to touch the codepath without posix extensions. What
about when unix extensions are enabled? The previous patch seems to
indicate that the behavior is that mfsymlinks are always used when that
mount option is used even if unix extensions are enabled. If so, then I
think you'll need a similar change in cifs_get_inode_info_unix.

>  	if (!*pinode) {
>  		*pinode = cifs_iget(sb, &fattr);
>  		if (!*pinode)
> diff --git a/fs/cifs/link.c b/fs/cifs/link.c
> index 2358a5f..985373c 100644
> --- a/fs/cifs/link.c
> +++ b/fs/cifs/link.c
> @@ -48,6 +48,14 @@ CIFSQueryMFSymLink(const int xid, struct cifsTconInfo *tcon,
>  }
>  
>  int
> +CIFSCheckMFSymlink(struct cifs_fattr *fattr,
> +		   const unsigned char *path,
> +		   struct cifs_sb_info *cifs_sb, int xid)
> +{
> +	return 0;
> +}
> +
> +int
>  cifs_hardlink(struct dentry *old_file, struct inode *inode,
>  	      struct dentry *direntry)
>  {


-- 
Jeff Layton <jlayton-eUNUBHrolfbYtjvyW6yDsg@public.gmane.org>

Re: [PATCH 3/8] cifs: add CIFSCheckMFSymlink() as stub

[Suresh Jayaraman]

On 08/04/2010 08:07 PM, Jeff Layton wrote:
> On Wed,  4 Aug 2010 16:11:44 +0200
> Stefan Metzmacher <metze-eUNUBHrolfbYtjvyW6yDsg@public.gmane.org> wrote:
> 
>> Signed-off-by: Stefan Metzmacher <metze-eUNUBHrolfbYtjvyW6yDsg@public.gmane.org>
>> ---
>>  fs/cifs/cifsproto.h |    3 +++
>>  fs/cifs/inode.c     |    7 +++++++
>>  fs/cifs/link.c      |    8 ++++++++
>>  3 files changed, 18 insertions(+), 0 deletions(-)
>>
>> diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h
>> index 2eaebbd..e94e095 100644
>> --- a/fs/cifs/cifsproto.h
>> +++ b/fs/cifs/cifsproto.h
>> @@ -409,4 +409,7 @@ extern int CIFSSMBSetPosixACL(const int xid, struct cifsTconInfo *tcon,
>>  extern int CIFSGetExtAttr(const int xid, struct cifsTconInfo *tcon,
>>  			const int netfid, __u64 *pExtAttrBits, __u64 *pMask);
>>  extern void cifs_autodisable_serverino(struct cifs_sb_info *cifs_sb);
>> +extern int CIFSCheckMFSymlink(struct cifs_fattr *fattr,
>> +		const unsigned char *path,
>> +		struct cifs_sb_info *cifs_sb, int xid);
>>  #endif			/* _CIFSPROTO_H */
>> diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c
>> index a15b3a9..c4121de 100644
>> --- a/fs/cifs/inode.c
>> +++ b/fs/cifs/inode.c
>> @@ -661,6 +661,13 @@ int cifs_get_inode_info(struct inode **pinode,
>>  	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_UNX_EMUL)
>>  		cifs_sfu_mode(&fattr, full_path, cifs_sb, xid);
>>  
>> +	/* query for SFU type info if supported and needed */
>> +	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS) {
>> +		tmprc = CIFSCheckMFSymlink(&fattr, full_path, cifs_sb, xid);
>> +		if (tmprc)
>> +			cFYI(1, "CIFSCheckMFSymlink: %d", tmprc);
>> +	}
>> +
> 
> 		^^^^^^^^^^^^^^
> 
> This only seems to touch the codepath without posix extensions. What
> about when unix extensions are enabled? The previous patch seems to
> indicate that the behavior is that mfsymlinks are always used when that
> mount option is used even if unix extensions are enabled. If so, then I
> think you'll need a similar change in cifs_get_inode_info_unix.
> 

I initially thought so. But, looking again - there is no point in
querying for SFU type info if unix extensions are enabled..?

Thanks,


-- 
Suresh Jayaraman

Re: [PATCH 3/8] cifs: add CIFSCheckMFSymlink() as stub

[Jeff Layton]

On Thu, 05 Aug 2010 17:40:36 +0530
Suresh Jayaraman <sjayaraman-l3A5Bk7waGM@public.gmane.org> wrote:

> On 08/04/2010 08:07 PM, Jeff Layton wrote:
> > On Wed,  4 Aug 2010 16:11:44 +0200
> > Stefan Metzmacher <metze-eUNUBHrolfbYtjvyW6yDsg@public.gmane.org> wrote:
> > 
> >> Signed-off-by: Stefan Metzmacher <metze-eUNUBHrolfbYtjvyW6yDsg@public.gmane.org>
> >> ---
> >>  fs/cifs/cifsproto.h |    3 +++
> >>  fs/cifs/inode.c     |    7 +++++++
> >>  fs/cifs/link.c      |    8 ++++++++
> >>  3 files changed, 18 insertions(+), 0 deletions(-)
> >>
> >> diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h
> >> index 2eaebbd..e94e095 100644
> >> --- a/fs/cifs/cifsproto.h
> >> +++ b/fs/cifs/cifsproto.h
> >> @@ -409,4 +409,7 @@ extern int CIFSSMBSetPosixACL(const int xid, struct cifsTconInfo *tcon,
> >>  extern int CIFSGetExtAttr(const int xid, struct cifsTconInfo *tcon,
> >>  			const int netfid, __u64 *pExtAttrBits, __u64 *pMask);
> >>  extern void cifs_autodisable_serverino(struct cifs_sb_info *cifs_sb);
> >> +extern int CIFSCheckMFSymlink(struct cifs_fattr *fattr,
> >> +		const unsigned char *path,
> >> +		struct cifs_sb_info *cifs_sb, int xid);
> >>  #endif			/* _CIFSPROTO_H */
> >> diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c
> >> index a15b3a9..c4121de 100644
> >> --- a/fs/cifs/inode.c
> >> +++ b/fs/cifs/inode.c
> >> @@ -661,6 +661,13 @@ int cifs_get_inode_info(struct inode **pinode,
> >>  	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_UNX_EMUL)
> >>  		cifs_sfu_mode(&fattr, full_path, cifs_sb, xid);
> >>  
> >> +	/* query for SFU type info if supported and needed */
> >> +	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS) {
> >> +		tmprc = CIFSCheckMFSymlink(&fattr, full_path, cifs_sb, xid);
> >> +		if (tmprc)
> >> +			cFYI(1, "CIFSCheckMFSymlink: %d", tmprc);
> >> +	}
> >> +
> > 
> > 		^^^^^^^^^^^^^^
> > 
> > This only seems to touch the codepath without posix extensions. What
> > about when unix extensions are enabled? The previous patch seems to
> > indicate that the behavior is that mfsymlinks are always used when that
> > mount option is used even if unix extensions are enabled. If so, then I
> > think you'll need a similar change in cifs_get_inode_info_unix.
> > 
> 
> I initially thought so. But, looking again - there is no point in
> querying for SFU type info if unix extensions are enabled..?
> 
> Thanks,
> 

I'm not sure that addresses the concern. It's very confusing, but:

    SFU != POSIX extensions

The SFU codepath goes through the "normal" cifs code
(cifs_get_inode_info). The POSIX extensions codepath goes through a
different codepath (cifs_get_inode_info_unix). Yes, all of this is
sorely in need of being cleaned up, but that's the way it works today...

Metze's patches seem to indicate that mfsymlinks and unix extensions
aren't mutually exclusive. The unix codepaths that determine inode
type and fill out inode data should be using the mfsymlink stuff too.

-- 
Jeff Layton <jlayton-eUNUBHrolfbYtjvyW6yDsg@public.gmane.org>

Re: [PATCH 3/8] cifs: add CIFSCheckMFSymlink() as stub

[Stefan (metze) Metzmacher]

[-- Attachment #1: Type: text/plain, Size: 5041 bytes --]

Hi,

I noticed that I also need to hook the cifs_readdir() path.

Can someone tell me how I can construct the file name
relative to the mount point. The TODO in this change.

--- a/fs/cifs/readdir.c
+++ b/fs/cifs/readdir.c
@@ -679,7 +679,7 @@ static int cifs_get_name_from_search_buf(struct qstr
*pqst,
        return rc;
 }

-static int cifs_filldir(char *pfindEntry, struct file *file, filldir_t
filldir,
+static int cifs_filldir(int xid, char *pfindEntry, struct file *file,
filldir_t filldir,
                        void *direntry, char *scratch_buf, unsigned int
max_len)
 {
        int rc = 0;
@@ -731,6 +731,15 @@ static int cifs_filldir(char *pfindEntry, struct
file *file, filldir_t filldir,
                cifs_dir_info_to_fattr(&fattr, (FILE_DIRECTORY_INFO *)
                                        pfindEntry, cifs_sb);

+       if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS) {
+               int tmprc;
+               const char *full_path = qstring.name;
+               /* TODO: build full path relative to the mount point */
+               tmprc = CIFSCheckMFSymlink(&fattr, full_path, cifs_sb, xid);
+               if (tmprc)
+                       cFYI(1, "CIFSCheckMFSymlink: %d", tmprc);
+       }
+
        if (inum && (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM)) {
                fattr.cf_uniqueid = inum;
        } else {
@@ -856,7 +865,7 @@ int cifs_readdir(struct file *file, void *direntry,
filldir_t filldir)
                        }
                        /* if buggy server returns . and .. late do
                        we want to check for that here? */
-                       rc = cifs_filldir(current_entry, file,
+                       rc = cifs_filldir(xid, current_entry, file,
                                        filldir, direntry, tmp_buf,
max_len);
                        if (rc == -EOVERFLOW) {
                                rc = 0;

metze

Am 05.08.2010 14:31, schrieb Jeff Layton:
> On Thu, 05 Aug 2010 17:40:36 +0530
> Suresh Jayaraman <sjayaraman-l3A5Bk7waGM@public.gmane.org> wrote:
> 
>> On 08/04/2010 08:07 PM, Jeff Layton wrote:
>>> On Wed,  4 Aug 2010 16:11:44 +0200
>>> Stefan Metzmacher <metze-eUNUBHrolfbYtjvyW6yDsg@public.gmane.org> wrote:
>>>
>>>> Signed-off-by: Stefan Metzmacher <metze-eUNUBHrolfbYtjvyW6yDsg@public.gmane.org>
>>>> ---
>>>>  fs/cifs/cifsproto.h |    3 +++
>>>>  fs/cifs/inode.c     |    7 +++++++
>>>>  fs/cifs/link.c      |    8 ++++++++
>>>>  3 files changed, 18 insertions(+), 0 deletions(-)
>>>>
>>>> diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h
>>>> index 2eaebbd..e94e095 100644
>>>> --- a/fs/cifs/cifsproto.h
>>>> +++ b/fs/cifs/cifsproto.h
>>>> @@ -409,4 +409,7 @@ extern int CIFSSMBSetPosixACL(const int xid, struct cifsTconInfo *tcon,
>>>>  extern int CIFSGetExtAttr(const int xid, struct cifsTconInfo *tcon,
>>>>  			const int netfid, __u64 *pExtAttrBits, __u64 *pMask);
>>>>  extern void cifs_autodisable_serverino(struct cifs_sb_info *cifs_sb);
>>>> +extern int CIFSCheckMFSymlink(struct cifs_fattr *fattr,
>>>> +		const unsigned char *path,
>>>> +		struct cifs_sb_info *cifs_sb, int xid);
>>>>  #endif			/* _CIFSPROTO_H */
>>>> diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c
>>>> index a15b3a9..c4121de 100644
>>>> --- a/fs/cifs/inode.c
>>>> +++ b/fs/cifs/inode.c
>>>> @@ -661,6 +661,13 @@ int cifs_get_inode_info(struct inode **pinode,
>>>>  	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_UNX_EMUL)
>>>>  		cifs_sfu_mode(&fattr, full_path, cifs_sb, xid);
>>>>  
>>>> +	/* query for SFU type info if supported and needed */
>>>> +	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS) {
>>>> +		tmprc = CIFSCheckMFSymlink(&fattr, full_path, cifs_sb, xid);
>>>> +		if (tmprc)
>>>> +			cFYI(1, "CIFSCheckMFSymlink: %d", tmprc);
>>>> +	}
>>>> +
>>>
>>> 		^^^^^^^^^^^^^^
>>>
>>> This only seems to touch the codepath without posix extensions. What
>>> about when unix extensions are enabled? The previous patch seems to
>>> indicate that the behavior is that mfsymlinks are always used when that
>>> mount option is used even if unix extensions are enabled. If so, then I
>>> think you'll need a similar change in cifs_get_inode_info_unix.
>>>
>>
>> I initially thought so. But, looking again - there is no point in
>> querying for SFU type info if unix extensions are enabled..?
>>
>> Thanks,
>>
> 
> I'm not sure that addresses the concern. It's very confusing, but:
> 
>     SFU != POSIX extensions
> 
> The SFU codepath goes through the "normal" cifs code
> (cifs_get_inode_info). The POSIX extensions codepath goes through a
> different codepath (cifs_get_inode_info_unix). Yes, all of this is
> sorely in need of being cleaned up, but that's the way it works today...
> 
> Metze's patches seem to indicate that mfsymlinks and unix extensions
> aren't mutually exclusive. The unix codepaths that determine inode
> type and fill out inode data should be using the mfsymlink stuff too.
> 


[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 262 bytes --]

Re: [PATCH 3/8] cifs: add CIFSCheckMFSymlink() as stub

[Suresh Jayaraman]

On 08/09/2010 07:34 PM, Stefan (metze) Metzmacher wrote:
> Hi,
> 
> I noticed that I also need to hook the cifs_readdir() path.
> 
> Can someone tell me how I can construct the file name
> relative to the mount point. The TODO in this change.

build_path_from_dentry() ?


-- 
Suresh Jayaraman

[PATCH 4/8] cifs: implement CIFSParseMFSymlink()

[Stefan Metzmacher]

Signed-off-by: Stefan Metzmacher <metze-eUNUBHrolfbYtjvyW6yDsg@public.gmane.org>
---
 fs/cifs/link.c |   62 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 62 insertions(+), 0 deletions(-)

diff --git a/fs/cifs/link.c b/fs/cifs/link.c
index 985373c..0d90a89 100644
--- a/fs/cifs/link.c
+++ b/fs/cifs/link.c
@@ -28,6 +28,68 @@
 #include "cifsproto.h"
 #include "cifs_debug.h"
 #include "cifs_fs_sb.h"
+#include "md5.h"
+
+#define CIFS_MF_SYMLINK_LEN_OFFSET (4+1)
+#define CIFS_MF_SYMLINK_MD5_OFFSET (CIFS_MF_SYMLINK_LEN_OFFSET+(4+1))
+#define CIFS_MF_SYMLINK_LINK_OFFSET (CIFS_MF_SYMLINK_MD5_OFFSET+(32+1))
+#define CIFS_MF_SYMLINK_LINK_MAXLEN (1024)
+#define CIFS_MF_SYMLINK_FILE_SIZE \
+	(CIFS_MF_SYMLINK_LINK_OFFSET + CIFS_MF_SYMLINK_LINK_MAXLEN)
+
+#define CIFS_MF_SYMLINK_LEN_FORMAT "XSym\n%04u\n"
+#define CIFS_MF_SYMLINK_MD5_FORMAT \
+	"%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x\n"
+#define CIFS_MF_SYMLINK_MD5_ARGS(md5_hash) \
+	md5_hash[0],  md5_hash[1],  md5_hash[2],  md5_hash[3], \
+	md5_hash[4],  md5_hash[5],  md5_hash[6],  md5_hash[7], \
+	md5_hash[8],  md5_hash[9],  md5_hash[10], md5_hash[11],\
+	md5_hash[12], md5_hash[13], md5_hash[14], md5_hash[15]
+
+static int
+CIFSParseMFSymlink(const u8 *buf,
+		   unsigned int buf_len,
+		   unsigned int *_link_len,
+		   char **_link_str)
+{
+	int rc;
+	unsigned int link_len;
+	const char *md5_str1;
+	const char *link_str;
+	struct MD5Context md5_ctx;
+	u8 md5_hash[16];
+	char md5_str2[34];
+
+	if (buf_len != CIFS_MF_SYMLINK_FILE_SIZE)
+		return -EINVAL;
+
+	md5_str1 = (const char *)&buf[CIFS_MF_SYMLINK_MD5_OFFSET];
+	link_str = (const char *)&buf[CIFS_MF_SYMLINK_LINK_OFFSET];
+
+	rc = sscanf(buf, CIFS_MF_SYMLINK_LEN_FORMAT, &link_len);
+	if (rc != 1)
+		return -EINVAL;
+
+	cifs_MD5_init(&md5_ctx);
+	cifs_MD5_update(&md5_ctx, (const u8 *)link_str, link_len);
+	cifs_MD5_final(md5_hash, &md5_ctx);
+
+	snprintf(md5_str2, sizeof(md5_str2),
+		 CIFS_MF_SYMLINK_MD5_FORMAT,
+		 CIFS_MF_SYMLINK_MD5_ARGS(md5_hash));
+
+	if (strncmp(md5_str1, md5_str2, 17) != 0)
+		return -EINVAL;
+
+	if (_link_str) {
+		*_link_str = kstrndup(link_str, link_len, GFP_KERNEL);
+		if (!*_link_str)
+			return -ENOMEM;
+	}
+
+	*_link_len = link_len;
+	return 0;
+}
 
 static int
 CIFSCreateMFSymLink(const int xid, struct cifsTconInfo *tcon,
-- 
1.7.0.4

[PATCH 5/8] cifs: implement CIFSCheckMFSymlink()

[Stefan Metzmacher]

Signed-off-by: Stefan Metzmacher <metze-eUNUBHrolfbYtjvyW6yDsg@public.gmane.org>
---
 fs/cifs/link.c |   65 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 65 insertions(+), 0 deletions(-)

diff --git a/fs/cifs/link.c b/fs/cifs/link.c
index 0d90a89..6cd0879 100644
--- a/fs/cifs/link.c
+++ b/fs/cifs/link.c
@@ -114,6 +114,71 @@ CIFSCheckMFSymlink(struct cifs_fattr *fattr,
 		   const unsigned char *path,
 		   struct cifs_sb_info *cifs_sb, int xid)
 {
+	int rc;
+	int oplock = 0;
+	__u16 netfid = 0;
+	struct cifsTconInfo *pTcon = cifs_sb->tcon;
+	u8 *buf;
+	char *pbuf;
+	unsigned int bytes_read = 0;
+	int buf_type = CIFS_NO_BUFFER;
+	unsigned int link_len = 0;
+	FILE_ALL_INFO file_info;
+
+	if (!(fattr->cf_mode & S_IFREG))
+		/* it's not a symlink */
+		return 0;
+
+	if (fattr->cf_eof != CIFS_MF_SYMLINK_FILE_SIZE)
+		/* it's not a symlink */
+		return 0;
+
+	buf = kmalloc(CIFS_MF_SYMLINK_FILE_SIZE, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+	pbuf = buf;
+
+	rc = CIFSSMBOpen(xid, pTcon, path, FILE_OPEN, GENERIC_READ,
+			 CREATE_NOT_DIR, &netfid, &oplock, &file_info,
+			 cifs_sb->local_nls,
+			 cifs_sb->mnt_cifs_flags &
+				CIFS_MOUNT_MAP_SPECIAL_CHR);
+	if (rc != 0) {
+		kfree(buf);
+		return rc;
+	}
+
+	if (file_info.EndOfFile != CIFS_MF_SYMLINK_FILE_SIZE) {
+		CIFSSMBClose(xid, pTcon, netfid);
+		kfree(buf);
+		/* it's not a symlink */
+		return 0;
+	}
+
+	/* Read header */
+	rc = CIFSSMBRead(xid, pTcon, netfid,
+			 CIFS_MF_SYMLINK_FILE_SIZE /* length */,
+			 0 /* offset */,
+			 &bytes_read, &pbuf, &buf_type);
+	CIFSSMBClose(xid, pTcon, netfid);
+	if (rc != 0) {
+		kfree(buf);
+		return rc;
+	}
+
+	rc = CIFSParseMFSymlink(buf, bytes_read, &link_len, NULL);
+	kfree(buf);
+	if (rc == -EINVAL)
+		/* it's not a symlink */
+		return 0;
+	if (rc != 0)
+		return rc;
+
+	/* it is a symlink */
+	fattr->cf_eof = link_len;
+	fattr->cf_mode &= ~S_IFMT;
+	fattr->cf_mode |= S_IFLNK;
+	fattr->cf_dtype = DT_LNK;
 	return 0;
 }
 
-- 
1.7.0.4

Re: [PATCH 5/8] cifs: implement CIFSCheckMFSymlink()

[Jeff Layton]

On Wed,  4 Aug 2010 16:11:46 +0200
Stefan Metzmacher <metze-eUNUBHrolfbYtjvyW6yDsg@public.gmane.org> wrote:

> Signed-off-by: Stefan Metzmacher <metze-eUNUBHrolfbYtjvyW6yDsg@public.gmane.org>
> ---
>  fs/cifs/link.c |   65 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 files changed, 65 insertions(+), 0 deletions(-)
> 
> diff --git a/fs/cifs/link.c b/fs/cifs/link.c
> index 0d90a89..6cd0879 100644
> --- a/fs/cifs/link.c
> +++ b/fs/cifs/link.c
> @@ -114,6 +114,71 @@ CIFSCheckMFSymlink(struct cifs_fattr *fattr,
>  		   const unsigned char *path,
>  		   struct cifs_sb_info *cifs_sb, int xid)
>  {
> +	int rc;
> +	int oplock = 0;
> +	__u16 netfid = 0;
> +	struct cifsTconInfo *pTcon = cifs_sb->tcon;
> +	u8 *buf;
> +	char *pbuf;
> +	unsigned int bytes_read = 0;
> +	int buf_type = CIFS_NO_BUFFER;
> +	unsigned int link_len = 0;
> +	FILE_ALL_INFO file_info;
> +
> +	if (!(fattr->cf_mode & S_IFREG))
> +		/* it's not a symlink */
> +		return 0;
> +
> +	if (fattr->cf_eof != CIFS_MF_SYMLINK_FILE_SIZE)
> +		/* it's not a symlink */
> +		return 0;
> +
> +	buf = kmalloc(CIFS_MF_SYMLINK_FILE_SIZE, GFP_KERNEL);
> +	if (!buf)
> +		return -ENOMEM;
> +	pbuf = buf;
> +
> +	rc = CIFSSMBOpen(xid, pTcon, path, FILE_OPEN, GENERIC_READ,
> +			 CREATE_NOT_DIR, &netfid, &oplock, &file_info,
> +			 cifs_sb->local_nls,
> +			 cifs_sb->mnt_cifs_flags &
> +				CIFS_MOUNT_MAP_SPECIAL_CHR);
> +	if (rc != 0) {
> +		kfree(buf);
> +		return rc;
> +	}
> +
> +	if (file_info.EndOfFile != CIFS_MF_SYMLINK_FILE_SIZE) {
> +		CIFSSMBClose(xid, pTcon, netfid);
> +		kfree(buf);
> +		/* it's not a symlink */
> +		return 0;
> +	}
> +

Might be better to move the kmalloc() here. If the open fails, or the
size is wrong you won't need the buffer. Allocating memory can lead to
reclaim events too, so it's best not to do it unless you really need it.

> +	/* Read header */
> +	rc = CIFSSMBRead(xid, pTcon, netfid,
> +			 CIFS_MF_SYMLINK_FILE_SIZE /* length */,
> +			 0 /* offset */,
> +			 &bytes_read, &pbuf, &buf_type);
> +	CIFSSMBClose(xid, pTcon, netfid);
> +	if (rc != 0) {
> +		kfree(buf);
> +		return rc;
> +	}
> +
> +	rc = CIFSParseMFSymlink(buf, bytes_read, &link_len, NULL);
> +	kfree(buf);
> +	if (rc == -EINVAL)
> +		/* it's not a symlink */
> +		return 0;
> +	if (rc != 0)
> +		return rc;
> +
> +	/* it is a symlink */
> +	fattr->cf_eof = link_len;
> +	fattr->cf_mode &= ~S_IFMT;
> +	fattr->cf_mode |= S_IFLNK;
> +	fattr->cf_dtype = DT_LNK;
>  	return 0;
>  }
>  


-- 
Jeff Layton <jlayton-eUNUBHrolfbYtjvyW6yDsg@public.gmane.org>

Re: [PATCH 5/8] cifs: implement CIFSCheckMFSymlink()

[Suresh Jayaraman]

On 08/04/2010 07:41 PM, Stefan Metzmacher wrote:
> Signed-off-by: Stefan Metzmacher <metze-eUNUBHrolfbYtjvyW6yDsg@public.gmane.org>
> ---
>  fs/cifs/link.c |   65 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 files changed, 65 insertions(+), 0 deletions(-)
> 
> diff --git a/fs/cifs/link.c b/fs/cifs/link.c
> index 0d90a89..6cd0879 100644
> --- a/fs/cifs/link.c
> +++ b/fs/cifs/link.c
> @@ -114,6 +114,71 @@ CIFSCheckMFSymlink(struct cifs_fattr *fattr,
>  		   const unsigned char *path,
>  		   struct cifs_sb_info *cifs_sb, int xid)
>  {
> +	int rc;
> +	int oplock = 0;
> +	__u16 netfid = 0;
> +	struct cifsTconInfo *pTcon = cifs_sb->tcon;
> +	u8 *buf;
> +	char *pbuf;
> +	unsigned int bytes_read = 0;
> +	int buf_type = CIFS_NO_BUFFER;
> +	unsigned int link_len = 0;
> +	FILE_ALL_INFO file_info;
> +
> +	if (!(fattr->cf_mode & S_IFREG))
> +		/* it's not a symlink */
> +		return 0;

Perhaps a little naive - what if cf_mode is S_IFDIR?

Thanks,


-- 
Suresh Jayaraman

Re: [PATCH 5/8] cifs: implement CIFSCheckMFSymlink()

[Stefan (metze) Metzmacher]

[-- Attachment #1: Type: text/plain, Size: 1120 bytes --]

Am 05.08.2010 14:44, schrieb Suresh Jayaraman:
> On 08/04/2010 07:41 PM, Stefan Metzmacher wrote:
>> Signed-off-by: Stefan Metzmacher <metze-eUNUBHrolfbYtjvyW6yDsg@public.gmane.org>
>> ---
>>  fs/cifs/link.c |   65 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>>  1 files changed, 65 insertions(+), 0 deletions(-)
>>
>> diff --git a/fs/cifs/link.c b/fs/cifs/link.c
>> index 0d90a89..6cd0879 100644
>> --- a/fs/cifs/link.c
>> +++ b/fs/cifs/link.c
>> @@ -114,6 +114,71 @@ CIFSCheckMFSymlink(struct cifs_fattr *fattr,
>>  		   const unsigned char *path,
>>  		   struct cifs_sb_info *cifs_sb, int xid)
>>  {
>> +	int rc;
>> +	int oplock = 0;
>> +	__u16 netfid = 0;
>> +	struct cifsTconInfo *pTcon = cifs_sb->tcon;
>> +	u8 *buf;
>> +	char *pbuf;
>> +	unsigned int bytes_read = 0;
>> +	int buf_type = CIFS_NO_BUFFER;
>> +	unsigned int link_len = 0;
>> +	FILE_ALL_INFO file_info;
>> +
>> +	if (!(fattr->cf_mode & S_IFREG))
>> +		/* it's not a symlink */
>> +		return 0;
> 
> Perhaps a little naive - what if cf_mode is S_IFDIR?

Then it's a directory and not a symlink.

metze


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[PATCH 6/8] cifs: implement CIFSQueryMFSymLink()

[Stefan Metzmacher]

Signed-off-by: Stefan Metzmacher <metze-eUNUBHrolfbYtjvyW6yDsg@public.gmane.org>
---
 fs/cifs/link.c |   54 ++++++++++++++++++++++++++++++++++++++++++++++++++----
 1 files changed, 50 insertions(+), 4 deletions(-)

diff --git a/fs/cifs/link.c b/fs/cifs/link.c
index 6cd0879..6d00712 100644
--- a/fs/cifs/link.c
+++ b/fs/cifs/link.c
@@ -103,10 +103,54 @@ CIFSCreateMFSymLink(const int xid, struct cifsTconInfo *tcon,
 static int
 CIFSQueryMFSymLink(const int xid, struct cifsTconInfo *tcon,
 		   const unsigned char *searchName, char **symlinkinfo,
-		   const struct nls_table *nls_codepage)
+		   const struct nls_table *nls_codepage, int remap)
 {
-	int rc = -EOPNOTSUPP;
-	return rc;
+	int rc;
+	int oplock = 0;
+	__u16 netfid = 0;
+	u8 *buf;
+	char *pbuf;
+	unsigned int bytes_read = 0;
+	int buf_type = CIFS_NO_BUFFER;
+	unsigned int link_len = 0;
+	FILE_ALL_INFO file_info;
+
+	buf = kmalloc(CIFS_MF_SYMLINK_FILE_SIZE, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+	pbuf = buf;
+
+	rc = CIFSSMBOpen(xid, tcon, searchName, FILE_OPEN, GENERIC_READ,
+			 CREATE_NOT_DIR, &netfid, &oplock, &file_info,
+			 nls_codepage, remap);
+	if (rc != 0) {
+		kfree(buf);
+		return rc;
+	}
+
+	if (file_info.EndOfFile != CIFS_MF_SYMLINK_FILE_SIZE) {
+		CIFSSMBClose(xid, tcon, netfid);
+		kfree(buf);
+		/* it's not a symlink */
+		return -EINVAL;
+	}
+
+	rc = CIFSSMBRead(xid, tcon, netfid,
+			 CIFS_MF_SYMLINK_FILE_SIZE /* length */,
+			 0 /* offset */,
+			 &bytes_read, &pbuf, &buf_type);
+	CIFSSMBClose(xid, tcon, netfid);
+	if (rc != 0) {
+		kfree(buf);
+		return rc;
+	}
+
+	rc = CIFSParseMFSymlink(buf, bytes_read, &link_len, symlinkinfo);
+	kfree(buf);
+	if (rc != 0)
+		return rc;
+
+	return 0;
 }
 
 int
@@ -297,7 +341,9 @@ cifs_follow_link(struct dentry *direntry, struct nameidata *nd)
 
 	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS)
 		rc = CIFSQueryMFSymLink(xid, tcon, full_path, &target_path,
-					cifs_sb->local_nls);
+					cifs_sb->local_nls,
+					cifs_sb->mnt_cifs_flags &
+						CIFS_MOUNT_MAP_SPECIAL_CHR);
 	else
 		rc = CIFSSMBUnixQuerySymLink(xid, tcon, full_path, &target_path,
 					     cifs_sb->local_nls);
-- 
1.7.0.4

[PATCH 7/8] cifs: implement CIFSFormatMFSymlink()

[Stefan Metzmacher]

Signed-off-by: Stefan Metzmacher <metze-eUNUBHrolfbYtjvyW6yDsg@public.gmane.org>
---
 fs/cifs/link.c |   42 ++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 42 insertions(+), 0 deletions(-)

diff --git a/fs/cifs/link.c b/fs/cifs/link.c
index 6d00712..89e09da 100644
--- a/fs/cifs/link.c
+++ b/fs/cifs/link.c
@@ -92,6 +92,48 @@ CIFSParseMFSymlink(const u8 *buf,
 }
 
 static int
+CIFSFormatMFSymlink(u8 *buf, unsigned int buf_len, const char *link_str)
+{
+	unsigned int link_len;
+	unsigned int ofs;
+	struct MD5Context md5_ctx;
+	u8 md5_hash[16];
+
+	if (buf_len != CIFS_MF_SYMLINK_FILE_SIZE)
+		return -EINVAL;
+
+	link_len = strlen(link_str);
+
+	if (link_len > CIFS_MF_SYMLINK_LINK_MAXLEN)
+		return -ENAMETOOLONG;
+
+	cifs_MD5_init(&md5_ctx);
+	cifs_MD5_update(&md5_ctx, (const u8 *)link_str, link_len);
+	cifs_MD5_final(md5_hash, &md5_ctx);
+
+	snprintf(buf, buf_len,
+		 CIFS_MF_SYMLINK_LEN_FORMAT CIFS_MF_SYMLINK_MD5_FORMAT,
+		 link_len,
+		 CIFS_MF_SYMLINK_MD5_ARGS(md5_hash));
+
+	ofs = CIFS_MF_SYMLINK_LINK_OFFSET;
+	memcpy(buf + ofs, link_str, link_len);
+
+	ofs += link_len;
+	if (ofs < CIFS_MF_SYMLINK_FILE_SIZE) {
+		buf[ofs] = '\n';
+		ofs++;
+	}
+
+	while (ofs < CIFS_MF_SYMLINK_FILE_SIZE) {
+		buf[ofs] = ' ';
+		ofs++;
+	}
+
+	return 0;
+}
+
+static int
 CIFSCreateMFSymLink(const int xid, struct cifsTconInfo *tcon,
 		    const char *fromName, const char *toName,
 		    const struct nls_table *nls_codepage)
-- 
1.7.0.4

[PATCH 8/8] cifs: implement CIFSCreateMFSymLink()

[Stefan Metzmacher]

Signed-off-by: Stefan Metzmacher <metze-eUNUBHrolfbYtjvyW6yDsg@public.gmane.org>
---
 fs/cifs/link.c |   45 +++++++++++++++++++++++++++++++++++++++++----
 1 files changed, 41 insertions(+), 4 deletions(-)

diff --git a/fs/cifs/link.c b/fs/cifs/link.c
index 89e09da..7fecd4f 100644
--- a/fs/cifs/link.c
+++ b/fs/cifs/link.c
@@ -136,10 +136,45 @@ CIFSFormatMFSymlink(u8 *buf, unsigned int buf_len, const char *link_str)
 static int
 CIFSCreateMFSymLink(const int xid, struct cifsTconInfo *tcon,
 		    const char *fromName, const char *toName,
-		    const struct nls_table *nls_codepage)
+		    const struct nls_table *nls_codepage, int remap)
 {
-	int rc = -EOPNOTSUPP;
-	return rc;
+	int rc;
+	int oplock = 0;
+	__u16 netfid = 0;
+	u8 *buf;
+	unsigned int bytes_written = 0;
+
+	buf = kmalloc(CIFS_MF_SYMLINK_FILE_SIZE, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	rc = CIFSFormatMFSymlink(buf, CIFS_MF_SYMLINK_FILE_SIZE, toName);
+	if (rc != 0) {
+		kfree(buf);
+		return rc;
+	}
+
+	rc = CIFSSMBOpen(xid, tcon, fromName, FILE_CREATE, GENERIC_WRITE,
+			 CREATE_NOT_DIR, &netfid, &oplock, NULL,
+			 nls_codepage, remap);
+	if (rc != 0) {
+		kfree(buf);
+		return rc;
+	}
+
+	rc = CIFSSMBWrite(xid, tcon, netfid,
+			  CIFS_MF_SYMLINK_FILE_SIZE /* length */,
+			  0 /* offset */,
+			  &bytes_written, buf, NULL, 0);
+	CIFSSMBClose(xid, tcon, netfid);
+	kfree(buf);
+	if (rc != 0)
+		return rc;
+
+	if (bytes_written != CIFS_MF_SYMLINK_FILE_SIZE)
+		return -EIO;
+
+	return 0;
 }
 
 static int
@@ -430,7 +465,9 @@ cifs_symlink(struct inode *inode, struct dentry *direntry, const char *symname)
 	/* BB what if DFS and this volume is on different share? BB */
 	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS)
 		rc = CIFSCreateMFSymLink(xid, pTcon, full_path, symname,
-					 cifs_sb->local_nls);
+					 cifs_sb->local_nls,
+					 cifs_sb->mnt_cifs_flags &
+						CIFS_MOUNT_MAP_SPECIAL_CHR);
 	else if (pTcon->unix_ext)
 		rc = CIFSUnixCreateSymLink(xid, pTcon, full_path, symname,
 					   cifs_sb->local_nls);
-- 
1.7.0.4