[linux-cifs-client,2/3,CIFS] Remote DFS root support. Try 2, fixed

Commit Message

Igor Mammedov April 1, 2009, 2:06 p.m. UTC

Sorry, I'm forgot to attach a patch.

Jeff Layton wrote:
> > On Tue, 17 Mar 2009 19:41:15 +0300
> > Igor Mammedov <[e-mail]> wrote:
> > 
> > Sorry for the delay in reviewing this.
> > 
>> >> Subject: [PATCH 2/3] [CIFS] Remote DFS root support.
>> >>
>> >>  Allows to mount share on a server that returns -EREMOTE
>> >>  at the tree connect stage or at the check on a full path
>> >>  accessibility.
>> >>
>> >> Signed-off-by: Igor Mammedov <[e-mail]>
>> >> ---
>> >>  fs/cifs/connect.c |  159 ++++++++++++++++++++++++++++++++++++++++++-----------
>> >>  1 files changed, 127 insertions(+), 32 deletions(-)
>> >>
>> >> diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
>> >> index cd4ccc8..abe54d2 100644
>> >> --- a/fs/cifs/connect.c
>> >> +++ b/fs/cifs/connect.c
>> >> @@ -2214,9 +2214,63 @@ is_path_accessible(int xid, struct cifsTconInfo *tcon,
>> >>  	return rc;
>> >>  }
>> >>  
>> >> +static void
>> >> +cleanup_volume_info(struct smb_vol **pvolume_info)
>> >> +{
>> >> +	struct smb_vol *volume_info;
>> >> +
>> >> +	if (!pvolume_info)
>> >> +		return;
>> >> +	volume_info = *pvolume_info;
>> >> +
>> >> +	if (!volume_info)
>> >> +		return;
>> >> +
>> >> +	if (volume_info->password != NULL) {
>> >> +		memset(volume_info->password, 0,
>> >> +				strlen(volume_info->password));
>> >> +		kfree(volume_info->password);
>> >> +	}
> > 
> > ^^^ this should probably turned into a kzfree() instead.
...

Comments

Jeff Layton April 1, 2009, 7:38 p.m. UTC | #1

On Wed, 01 Apr 2009 18:06:58 +0400
Igor Mammedov <[e-mail]> wrote:

> >From 44c0a1740dd9f22f861152b0a17e637ee301362e Mon Sep 17 00:00:00 2001  
> From: Igor Mammedov <[e-mail]>
> Date: Wed, 1 Apr 2009 17:54:42 +0400
> Subject: [PATCH 2/3] [CIFS] Remote DFS root support.
> 
> Allows to mount share on a server that returns -EREMOTE
>  at the tree connect stage or at the check on a full path
>  accessibility.
> 
> Signed-off-by: Igor Mammedov <[e-mail]>
> ---
>  fs/cifs/connect.c |  152 +++++++++++++++++++++++++++++++++++++++++-----------
>  1 files changed, 120 insertions(+), 32 deletions(-)
> 
> diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
> index b173b01..7f3b6c2 100644
> --- a/fs/cifs/connect.c
> +++ b/fs/cifs/connect.c
> @@ -2214,9 +2214,56 @@ is_path_accessible(int xid, struct cifsTconInfo *tcon,
>  	return rc;
>  }
>  
> +static void
> +cleanup_volume_info(struct smb_vol **pvolume_info)
> +{
> +	struct smb_vol *volume_info;
> +
> +	if (!pvolume_info && !*pvolume_info)
> +		return;
> +
> +	volume_info = *pvolume_info;
> +	kzfree(volume_info->password);
> +	kfree(volume_info->UNC);
> +	kfree(volume_info->prepath);
> +	kfree(volume_info);
> +	*pvolume_info = NULL;
> +	return;
> +}
> +
> +/* build_path_to_root returns full path to root when
> + * we do not have an exiting connection (tcon) */
> +static char *
> +build_path_to_root(const struct smb_vol *volume_info,
> +		const struct cifs_sb_info *cifs_sb)
> +{
> +	char *full_path;
> +
> +	int unc_len = strnlen(volume_info->UNC, MAX_TREE_SIZE + 1);
> +	full_path = kmalloc(unc_len + cifs_sb->prepathlen + 1, GFP_KERNEL);
> +	if (full_path == NULL)
> +		return ERR_PTR(-ENOMEM);
> +
> +	strncpy(full_path, volume_info->UNC, unc_len);
> +	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_POSIX_PATHS) {
> +		int i;
> +		for (i = 0; i < unc_len; i++) {
> +			if (full_path[i] == '\\')
> +				full_path[i] = '/';
> +		}
> +	}
> +
> +	if (cifs_sb->prepathlen)
> +		strncpy(full_path + unc_len, cifs_sb->prepath,
> +				cifs_sb->prepathlen);
> +
> +	full_path[unc_len + cifs_sb->prepathlen] = 0; /* add trailing null */
> +	return full_path;
> +}
> +
>  int
>  cifs_mount(struct super_block *sb, struct cifs_sb_info *cifs_sb,
> -	   char *mount_data, const char *devname)
> +		char *mount_data_global, const char *devname)
>  {
>  	int rc = 0;
>  	int xid;
> @@ -2225,6 +2272,13 @@ cifs_mount(struct super_block *sb, struct cifs_sb_info *cifs_sb,
>  	struct cifsTconInfo *tcon = NULL;
>  	struct TCP_Server_Info *srvTcp = NULL;
>  	char   *full_path;
> +	struct dfs_info3_param *referrals = NULL;
> +	unsigned int num_referrals = 0;
> +
> +	char *mount_data = mount_data_global;
> +
> +try_mount_again:
> +	full_path = NULL;
>  
>  	xid = GetXid();
>  
> @@ -2371,11 +2425,9 @@ cifs_mount(struct super_block *sb, struct cifs_sb_info *cifs_sb,
>  				}
>  			}
>  
> -			/* check for null share name ie connect to dfs root */
>  			if ((strchr(volume_info->UNC + 3, '\\') == NULL)
>  			    && (strchr(volume_info->UNC + 3, '/') == NULL)) {
> -				/* rc = connect_to_dfs_path(...) */
> -				cFYI(1, ("DFS root not supported"));
> +				cERROR(1, ("Missing share name"));
>  				rc = -ENODEV;
>  				goto mount_fail_check;
>  			} else {
> @@ -2392,7 +2444,7 @@ cifs_mount(struct super_block *sb, struct cifs_sb_info *cifs_sb,
>  				}
>  			}
>  			if (rc)
> -				goto mount_fail_check;
> +				goto remote_path_check;
>  			tcon->seal = volume_info->seal;
>  			write_lock(&cifs_tcp_ses_lock);
>  			list_add(&tcon->tcon_list, &pSesInfo->tcon_list);
> @@ -2417,19 +2469,9 @@ cifs_mount(struct super_block *sb, struct cifs_sb_info *cifs_sb,
>  	/* BB FIXME fix time_gran to be larger for LANMAN sessions */
>  	sb->s_time_gran = 100;
>  
> -mount_fail_check:
> -	/* on error free sesinfo and tcon struct if needed */
> -	if (rc) {
> -		/* If find_unc succeeded then rc == 0 so we can not end */
> -		/* up accidently freeing someone elses tcon struct */
> -		if (tcon)
> -			cifs_put_tcon(tcon);
> -		else if (pSesInfo)
> -			cifs_put_smb_ses(pSesInfo);
> -		else
> -			cifs_put_tcp_session(srvTcp);
> -		goto out;
> -	}
> +	if (rc)
> +		goto remote_path_check;
> +
>  	cifs_sb->tcon = tcon;
>  
>  	/* do not care if following two calls succeed - informational */
> @@ -2461,7 +2503,9 @@ mount_fail_check:
>  		cifs_sb->rsize = min(cifs_sb->rsize,
>  			       (tcon->ses->server->maxBuf - MAX_CIFS_HDR_SIZE));
>  
> -	if (!rc && cifs_sb->prepathlen) {
> +remote_path_check:
> +	/* check if a whole path (including prepath) is not remote */
> +	if (!rc && cifs_sb->prepathlen && tcon) {
>  		/* build_path_to_root works only when we have a valid tcon */
>  		full_path = cifs_build_path_to_root(cifs_sb);
>  		if (full_path == NULL) {
> @@ -2469,31 +2513,75 @@ mount_fail_check:
>  			goto mount_fail_check;
>  		}
>  		rc = is_path_accessible(xid, tcon, cifs_sb, full_path);
> -		if (rc) {
> -			cERROR(1, ("Path %s in not accessible: %d",
> -						full_path, rc));
> +		if (rc != -EREMOTE) {
>  			kfree(full_path);
>  			goto mount_fail_check;
>  		}
>  		kfree(full_path);
>  	}
>  
> +	/* get referral if needed */
> +	if (rc == -EREMOTE) {
> +		/* convert forward to back slashes in prepath here if needed */
> +		if ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_POSIX_PATHS) == 0)
> +			convert_delimiter(cifs_sb->prepath,
> +					CIFS_DIR_SEP(cifs_sb));
> +		full_path = build_path_to_root(volume_info, cifs_sb);
> +		if (IS_ERR(full_path)) {
> +			rc = PTR_ERR(full_path);
> +			goto mount_fail_check;
> +		}
> +
> +		cFYI(1, ("Getting referral for: %s", full_path));
> +		rc = get_dfs_path(xid, pSesInfo , full_path + 1,
> +			cifs_sb->local_nls, &num_referrals, &referrals,
> +			cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR);
> +		if (!rc && num_referrals > 0) {
> +			char *fake_devname = NULL;
> +
> +			if (mount_data != mount_data_global)
> +				kfree(mount_data);
> +			mount_data = cifs_compose_mount_options(
> +					cifs_sb->mountdata, full_path + 1,
> +					referrals, &fake_devname);
> +			kfree(fake_devname);
> +			free_dfs_info_array(referrals, num_referrals);
> +
> +			if (tcon)
> +				cifs_put_tcon(tcon);
> +			else if (pSesInfo)
> +				cifs_put_smb_ses(pSesInfo);
> +
> +			cleanup_volume_info(&volume_info);
> +			FreeXid(xid);
> +			kfree(full_path);
> +			goto try_mount_again;
> +		}
> +	}
> +
> +mount_fail_check:
> +	/* on error free sesinfo and tcon struct if needed */
> +	if (rc) {
> +		if (mount_data != mount_data_global)
> +			kfree(mount_data);
> +		/* If find_unc succeeded then rc == 0 so we can not end */
> +		/* up accidently freeing someone elses tcon struct */
> +		if (tcon)
> +			cifs_put_tcon(tcon);
> +		else if (pSesInfo)
> +			cifs_put_smb_ses(pSesInfo);
> +		else
> +			cifs_put_tcp_session(srvTcp);
> +		goto out;
> +	}
> +
>  	/* volume_info->password is freed above when existing session found
>  	(in which case it is not needed anymore) but when new sesion is created
>  	the password ptr is put in the new session structure (in which case the
>  	password will be freed at unmount time) */
>  out:
>  	/* zero out password before freeing */
> -	if (volume_info) {
> -		if (volume_info->password != NULL) {
> -			memset(volume_info->password, 0,
> -				strlen(volume_info->password));
> -			kfree(volume_info->password);
> -		}
> -		kfree(volume_info->UNC);
> -		kfree(volume_info->prepath);
> -		kfree(volume_info);
> -	}
> +	cleanup_volume_info(&volume_info);
>  	FreeXid(xid);
>  	return rc;
>  }
> -- 
> 1.6.0.2
> 

Looks fine to me. I'd like to eventually see this code defer the "puts"
until after the final mount is done, but that's really just an
optimization and can wait.

Acked-by: Jeff Layton <[e-mail]>

Patch

>From 44c0a1740dd9f22f861152b0a17e637ee301362e Mon Sep 17 00:00:00 2001
From: Igor Mammedov <[e-mail]>
Date: Wed, 1 Apr 2009 17:54:42 +0400
Subject: [PATCH 2/3] [CIFS] Remote DFS root support.

Allows to mount share on a server that returns -EREMOTE
 at the tree connect stage or at the check on a full path
 accessibility.

Signed-off-by: Igor Mammedov <[e-mail]>
---
 fs/cifs/connect.c |  152 +++++++++++++++++++++++++++++++++++++++++-----------
 1 files changed, 120 insertions(+), 32 deletions(-)

diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index b173b01..7f3b6c2 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -2214,9 +2214,56 @@  is_path_accessible(int xid, struct cifsTconInfo *tcon,
 	return rc;
 }
 
+static void
+cleanup_volume_info(struct smb_vol **pvolume_info)
+{
+	struct smb_vol *volume_info;
+
+	if (!pvolume_info && !*pvolume_info)
+		return;
+
+	volume_info = *pvolume_info;
+	kzfree(volume_info->password);
+	kfree(volume_info->UNC);
+	kfree(volume_info->prepath);
+	kfree(volume_info);
+	*pvolume_info = NULL;
+	return;
+}
+
+/* build_path_to_root returns full path to root when
+ * we do not have an exiting connection (tcon) */
+static char *
+build_path_to_root(const struct smb_vol *volume_info,
+		const struct cifs_sb_info *cifs_sb)
+{
+	char *full_path;
+
+	int unc_len = strnlen(volume_info->UNC, MAX_TREE_SIZE + 1);
+	full_path = kmalloc(unc_len + cifs_sb->prepathlen + 1, GFP_KERNEL);
+	if (full_path == NULL)
+		return ERR_PTR(-ENOMEM);
+
+	strncpy(full_path, volume_info->UNC, unc_len);
+	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_POSIX_PATHS) {
+		int i;
+		for (i = 0; i < unc_len; i++) {
+			if (full_path[i] == '\\')
+				full_path[i] = '/';
+		}
+	}
+
+	if (cifs_sb->prepathlen)
+		strncpy(full_path + unc_len, cifs_sb->prepath,
+				cifs_sb->prepathlen);
+
+	full_path[unc_len + cifs_sb->prepathlen] = 0; /* add trailing null */
+	return full_path;
+}
+
 int
 cifs_mount(struct super_block *sb, struct cifs_sb_info *cifs_sb,
-	   char *mount_data, const char *devname)
+		char *mount_data_global, const char *devname)
 {
 	int rc = 0;
 	int xid;
@@ -2225,6 +2272,13 @@  cifs_mount(struct super_block *sb, struct cifs_sb_info *cifs_sb,
 	struct cifsTconInfo *tcon = NULL;
 	struct TCP_Server_Info *srvTcp = NULL;
 	char   *full_path;
+	struct dfs_info3_param *referrals = NULL;
+	unsigned int num_referrals = 0;
+
+	char *mount_data = mount_data_global;
+
+try_mount_again:
+	full_path = NULL;
 
 	xid = GetXid();
 
@@ -2371,11 +2425,9 @@  cifs_mount(struct super_block *sb, struct cifs_sb_info *cifs_sb,
 				}
 			}
 
-			/* check for null share name ie connect to dfs root */
 			if ((strchr(volume_info->UNC + 3, '\\') == NULL)
 			    && (strchr(volume_info->UNC + 3, '/') == NULL)) {
-				/* rc = connect_to_dfs_path(...) */
-				cFYI(1, ("DFS root not supported"));
+				cERROR(1, ("Missing share name"));
 				rc = -ENODEV;
 				goto mount_fail_check;
 			} else {
@@ -2392,7 +2444,7 @@  cifs_mount(struct super_block *sb, struct cifs_sb_info *cifs_sb,
 				}
 			}
 			if (rc)
-				goto mount_fail_check;
+				goto remote_path_check;
 			tcon->seal = volume_info->seal;
 			write_lock(&cifs_tcp_ses_lock);
 			list_add(&tcon->tcon_list, &pSesInfo->tcon_list);
@@ -2417,19 +2469,9 @@  cifs_mount(struct super_block *sb, struct cifs_sb_info *cifs_sb,
 	/* BB FIXME fix time_gran to be larger for LANMAN sessions */
 	sb->s_time_gran = 100;
 
-mount_fail_check:
-	/* on error free sesinfo and tcon struct if needed */
-	if (rc) {
-		/* If find_unc succeeded then rc == 0 so we can not end */
-		/* up accidently freeing someone elses tcon struct */
-		if (tcon)
-			cifs_put_tcon(tcon);
-		else if (pSesInfo)
-			cifs_put_smb_ses(pSesInfo);
-		else
-			cifs_put_tcp_session(srvTcp);
-		goto out;
-	}
+	if (rc)
+		goto remote_path_check;
+
 	cifs_sb->tcon = tcon;
 
 	/* do not care if following two calls succeed - informational */
@@ -2461,7 +2503,9 @@  mount_fail_check:
 		cifs_sb->rsize = min(cifs_sb->rsize,
 			       (tcon->ses->server->maxBuf - MAX_CIFS_HDR_SIZE));
 
-	if (!rc && cifs_sb->prepathlen) {
+remote_path_check:
+	/* check if a whole path (including prepath) is not remote */
+	if (!rc && cifs_sb->prepathlen && tcon) {
 		/* build_path_to_root works only when we have a valid tcon */
 		full_path = cifs_build_path_to_root(cifs_sb);
 		if (full_path == NULL) {
@@ -2469,31 +2513,75 @@  mount_fail_check:
 			goto mount_fail_check;
 		}
 		rc = is_path_accessible(xid, tcon, cifs_sb, full_path);
-		if (rc) {
-			cERROR(1, ("Path %s in not accessible: %d",
-						full_path, rc));
+		if (rc != -EREMOTE) {
 			kfree(full_path);
 			goto mount_fail_check;
 		}
 		kfree(full_path);
 	}
 
+	/* get referral if needed */
+	if (rc == -EREMOTE) {
+		/* convert forward to back slashes in prepath here if needed */
+		if ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_POSIX_PATHS) == 0)
+			convert_delimiter(cifs_sb->prepath,
+					CIFS_DIR_SEP(cifs_sb));
+		full_path = build_path_to_root(volume_info, cifs_sb);
+		if (IS_ERR(full_path)) {
+			rc = PTR_ERR(full_path);
+			goto mount_fail_check;
+		}
+
+		cFYI(1, ("Getting referral for: %s", full_path));
+		rc = get_dfs_path(xid, pSesInfo , full_path + 1,
+			cifs_sb->local_nls, &num_referrals, &referrals,
+			cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR);
+		if (!rc && num_referrals > 0) {
+			char *fake_devname = NULL;
+
+			if (mount_data != mount_data_global)
+				kfree(mount_data);
+			mount_data = cifs_compose_mount_options(
+					cifs_sb->mountdata, full_path + 1,
+					referrals, &fake_devname);
+			kfree(fake_devname);
+			free_dfs_info_array(referrals, num_referrals);
+
+			if (tcon)
+				cifs_put_tcon(tcon);
+			else if (pSesInfo)
+				cifs_put_smb_ses(pSesInfo);
+
+			cleanup_volume_info(&volume_info);
+			FreeXid(xid);
+			kfree(full_path);
+			goto try_mount_again;
+		}
+	}
+
+mount_fail_check:
+	/* on error free sesinfo and tcon struct if needed */
+	if (rc) {
+		if (mount_data != mount_data_global)
+			kfree(mount_data);
+		/* If find_unc succeeded then rc == 0 so we can not end */
+		/* up accidently freeing someone elses tcon struct */
+		if (tcon)
+			cifs_put_tcon(tcon);
+		else if (pSesInfo)
+			cifs_put_smb_ses(pSesInfo);
+		else
+			cifs_put_tcp_session(srvTcp);
+		goto out;
+	}
+
 	/* volume_info->password is freed above when existing session found
 	(in which case it is not needed anymore) but when new sesion is created
 	the password ptr is put in the new session structure (in which case the
 	password will be freed at unmount time) */
 out:
 	/* zero out password before freeing */
-	if (volume_info) {
-		if (volume_info->password != NULL) {
-			memset(volume_info->password, 0,
-				strlen(volume_info->password));
-			kfree(volume_info->password);
-		}
-		kfree(volume_info->UNC);
-		kfree(volume_info->prepath);
-		kfree(volume_info);
-	}
+	cleanup_volume_info(&volume_info);
 	FreeXid(xid);
 	return rc;
 }
-- 
1.6.0.2