diff mbox

[2/2] btrfs-progs: fix the file system root is regarded as non-root

Message ID 54927765.6060207@jp.fujitsu.com (mailing list archive)
State Not Applicable
Headers show

Commit Message

Satoru Takeuchi Dec. 18, 2014, 6:42 a.m. UTC
From: Satoru Takeuchi <takeuchi_satoru@jp.fujitsu.com>

When "/" is Btrfs, "btrfs property <subcommand> /" regards it
as non-root by mistake.

check_is_root() regards @object as a file system root if
the following two conditions are satisfied.

 a) Both @object and its parent directory are Btrfs object
    (file system root, subvolume, inode, and device
    used for Btrfs).
 b) fsid of the above mentioned two objects are different.

It doesn't work if @object is "/" because, in this case,
fsid of "/" and its parent (it's also "/"), are the same.

* Test environment

Two Btrfs file system (not subvolume) "/" and "/home/sat/mnt".

* How to reproduce

Submit "btrfs prop get" against the above mentioned file systems.

* Test Result

** Actual result (without my patch)

Comments

Gui Hecheng Dec. 18, 2014, 7:09 a.m. UTC | #1
On Thu, 2014-12-18 at 15:42 +0900, Satoru Takeuchi wrote:
> From: Satoru Takeuchi <takeuchi_satoru@jp.fujitsu.com>
> 
> When "/" is Btrfs, "btrfs property <subcommand> /" regards it
> as non-root by mistake.
> 
> check_is_root() regards @object as a file system root if
> the following two conditions are satisfied.
> 
>  a) Both @object and its parent directory are Btrfs object
>     (file system root, subvolume, inode, and device
>     used for Btrfs).
>  b) fsid of the above mentioned two objects are different.
> 
> It doesn't work if @object is "/" because, in this case,
> fsid of "/" and its parent (it's also "/"), are the same.
> 
> * Test environment
> 
> Two Btrfs file system (not subvolume) "/" and "/home/sat/mnt".
> 
> * How to reproduce
> 
> Submit "btrfs prop get" against the above mentioned file systems.
> 
> * Test Result
> 
> ** Actual result (without my patch)
> 
> ==========================
> # btrfs prop get /home/sat/mnt/
> ro=false
> label=                 # label is displayed because it's a file system root
> # btrfs prop get /
> ro=false               # label is not displayed even if it's a file system root
> ==========================
> ** Expected result (with my patch)
> 
> ==========================
> # ./btrfs-new prop get btrfs-auto-test/
> # ./btrfs-new prop get /home/sat/mnt/
> ro=false
> label=
> # ./btrfs-new prop get /             
> ro=false
> label=foo            # label is displayed
> ===========================
> 
> Signed-off-by: Satoru Takeuchi <takeuchi_satoru@jp.fujitsu.com>
> Reported-by: Naohiro Aota <naota@elisp.net>
> 
> ---
>  cmds-property.c | 15 ++++++++++++++-
>  1 file changed, 14 insertions(+), 1 deletion(-)
> 
> diff --git a/cmds-property.c b/cmds-property.c
> index a4bc127..640af99 100644
> --- a/cmds-property.c
> +++ b/cmds-property.c
> @@ -125,11 +125,22 @@ static int check_is_root(const char *object)
>  	u8 fsid[BTRFS_FSID_SIZE];
>  	u8 fsid2[BTRFS_FSID_SIZE];
>  	char *tmp;
> +	char *rp;
> +
> +	rp = realpath(object, NULL);
> +	if (!rp) {
> +		ret = -ENOMEM;
Hi Satoru?

IMO, ret = -errno may be better, because there are many possible return
values of realpath().

Thanks,
Gui

> +		goto out;
> +	}
> +	if (!strcmp(rp, "/")) {
> +		ret = 0;
> +		goto free_rp_out;
> +	}
>  
>  	tmp = malloc(strlen(object) + 5);
>  	if (!tmp) {
>  		ret = -ENOMEM;
> -		goto out;
> +		goto free_rp_out;
>  	}
>  	strcpy(tmp, object);
>  	if (tmp[strlen(tmp) - 1] != '/')
> @@ -165,6 +176,8 @@ static int check_is_root(const char *object)
>  
>  free_tmp_out:
>  	free(tmp);
> +free_rp_out:
> +	free(rp);
>  out:
>  	return ret;
>  }


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Satoru Takeuchi Dec. 18, 2014, 7:19 a.m. UTC | #2
On 2014/12/18 16:09, Gui Hecheng wrote:
> On Thu, 2014-12-18 at 15:42 +0900, Satoru Takeuchi wrote:
>> From: Satoru Takeuchi <takeuchi_satoru@jp.fujitsu.com>
>>
>> When "/" is Btrfs, "btrfs property <subcommand> /" regards it
>> as non-root by mistake.
>>
>> check_is_root() regards @object as a file system root if
>> the following two conditions are satisfied.
>>
>>   a) Both @object and its parent directory are Btrfs object
>>      (file system root, subvolume, inode, and device
>>      used for Btrfs).
>>   b) fsid of the above mentioned two objects are different.
>>
>> It doesn't work if @object is "/" because, in this case,
>> fsid of "/" and its parent (it's also "/"), are the same.
>>
>> * Test environment
>>
>> Two Btrfs file system (not subvolume) "/" and "/home/sat/mnt".
>>
>> * How to reproduce
>>
>> Submit "btrfs prop get" against the above mentioned file systems.
>>
>> * Test Result
>>
>> ** Actual result (without my patch)
>>
>> ==========================
>> # btrfs prop get /home/sat/mnt/
>> ro=false
>> label=                 # label is displayed because it's a file system root
>> # btrfs prop get /
>> ro=false               # label is not displayed even if it's a file system root
>> ==========================
>> ** Expected result (with my patch)
>>
>> ==========================
>> # ./btrfs-new prop get btrfs-auto-test/
>> # ./btrfs-new prop get /home/sat/mnt/
>> ro=false
>> label=
>> # ./btrfs-new prop get /
>> ro=false
>> label=foo            # label is displayed
>> ===========================
>>
>> Signed-off-by: Satoru Takeuchi <takeuchi_satoru@jp.fujitsu.com>
>> Reported-by: Naohiro Aota <naota@elisp.net>
>>
>> ---
>>   cmds-property.c | 15 ++++++++++++++-
>>   1 file changed, 14 insertions(+), 1 deletion(-)
>>
>> diff --git a/cmds-property.c b/cmds-property.c
>> index a4bc127..640af99 100644
>> --- a/cmds-property.c
>> +++ b/cmds-property.c
>> @@ -125,11 +125,22 @@ static int check_is_root(const char *object)
>>   	u8 fsid[BTRFS_FSID_SIZE];
>>   	u8 fsid2[BTRFS_FSID_SIZE];
>>   	char *tmp;
>> +	char *rp;
>> +
>> +	rp = realpath(object, NULL);
>> +	if (!rp) {
>> +		ret = -ENOMEM;
> Hi Satoru?
>
> IMO, ret = -errno may be better, because there are many possible return
> values of realpath().

Thank you for point my mistake out.

I'll dispose 1/2 and submit 2/2 vs later.

Thanks,
Satoru

>
> Thanks,
> Gui
>
>> +		goto out;
>> +	}
>> +	if (!strcmp(rp, "/")) {
>> +		ret = 0;
>> +		goto free_rp_out;
>> +	}
>>
>>   	tmp = malloc(strlen(object) + 5);
>>   	if (!tmp) {
>>   		ret = -ENOMEM;
>> -		goto out;
>> +		goto free_rp_out;
>>   	}
>>   	strcpy(tmp, object);
>>   	if (tmp[strlen(tmp) - 1] != '/')
>> @@ -165,6 +176,8 @@ static int check_is_root(const char *object)
>>
>>   free_tmp_out:
>>   	free(tmp);
>> +free_rp_out:
>> +	free(rp);
>>   out:
>>   	return ret;
>>   }
>
>
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>

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diff mbox

Patch

==========================
# btrfs prop get /home/sat/mnt/
ro=false
label=                 # label is displayed because it's a file system root
# btrfs prop get /
ro=false               # label is not displayed even if it's a file system root
==========================
** Expected result (with my patch)

==========================
# ./btrfs-new prop get btrfs-auto-test/
# ./btrfs-new prop get /home/sat/mnt/
ro=false
label=
# ./btrfs-new prop get /             
ro=false
label=foo            # label is displayed
===========================

Signed-off-by: Satoru Takeuchi <takeuchi_satoru@jp.fujitsu.com>
Reported-by: Naohiro Aota <naota@elisp.net>

---
 cmds-property.c | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/cmds-property.c b/cmds-property.c
index a4bc127..640af99 100644
--- a/cmds-property.c
+++ b/cmds-property.c
@@ -125,11 +125,22 @@  static int check_is_root(const char *object)
 	u8 fsid[BTRFS_FSID_SIZE];
 	u8 fsid2[BTRFS_FSID_SIZE];
 	char *tmp;
+	char *rp;
+
+	rp = realpath(object, NULL);
+	if (!rp) {
+		ret = -ENOMEM;
+		goto out;
+	}
+	if (!strcmp(rp, "/")) {
+		ret = 0;
+		goto free_rp_out;
+	}
 
 	tmp = malloc(strlen(object) + 5);
 	if (!tmp) {
 		ret = -ENOMEM;
-		goto out;
+		goto free_rp_out;
 	}
 	strcpy(tmp, object);
 	if (tmp[strlen(tmp) - 1] != '/')
@@ -165,6 +176,8 @@  static int check_is_root(const char *object)
 
 free_tmp_out:
 	free(tmp);
+free_rp_out:
+	free(rp);
 out:
 	return ret;
 }