Ocfs2 devel - Jan 2009 - [PATCH] ocfs2: return f_fsid info in ocfs2_statfs()

Currently f_fsid of struct kstatfs returned from ocfs2_statfs() is undefined (at
least it should be
filled with 0). Since in some conditions, f_fsid value might be used as (f_fsid,
ino) pare to
uniquely identify a file, ocfs2 should return a defined unique f_fsid value from
ocfs2_statfs().

This patch uses uuid_hash as a unique ID to initiate f_fsid value, the 32bits
width is enough for
ocfs2 membership so far.

Signed-off-by: Coly Li <coly.li at suse.de>
---
 fs/ocfs2/super.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/fs/ocfs2/super.c b/fs/ocfs2/super.c
index 43ed113..fdab98a 100644
--- a/fs/ocfs2/super.c
+++ b/fs/ocfs2/super.c
@@ -1425,6 +1425,8 @@ static int ocfs2_statfs(struct dentry *dentry, struct
kstatfs *buf)
 	buf->f_bavail = buf->f_bfree;
 	buf->f_files = numbits;
 	buf->f_ffree = freebits;
+	buf->f_fsid.val[0] = osb->uuid_hash & 0xFFFFFFFFUL;
+	buf->f_fsid.val[1] = 0;

 	brelse(bh);

-- 
Coly Li
SuSE Labs

Wondering whether this id needs to be endian consistent.
For failover nfs setups maybe.

Coly Li wrote:
> Currently f_fsid of struct kstatfs returned from ocfs2_statfs() is
undefined (at least it should be
> filled with 0). Since in some conditions, f_fsid value might be used as
(f_fsid, ino) pare to
> uniquely identify a file, ocfs2 should return a defined unique f_fsid value
from ocfs2_statfs().
>
> This patch uses uuid_hash as a unique ID to initiate f_fsid value, the
32bits width is enough for
> ocfs2 membership so far.
>
> Signed-off-by: Coly Li <coly.li at suse.de>
> ---
>  fs/ocfs2/super.c |    2 ++
>  1 files changed, 2 insertions(+), 0 deletions(-)
>
> diff --git a/fs/ocfs2/super.c b/fs/ocfs2/super.c
> index 43ed113..fdab98a 100644
> --- a/fs/ocfs2/super.c
> +++ b/fs/ocfs2/super.c
> @@ -1425,6 +1425,8 @@ static int ocfs2_statfs(struct dentry *dentry, struct
kstatfs *buf)
>  	buf->f_bavail = buf->f_bfree;
>  	buf->f_files = numbits;
>  	buf->f_ffree = freebits;
> +	buf->f_fsid.val[0] = osb->uuid_hash & 0xFFFFFFFFUL;
> +	buf->f_fsid.val[1] = 0;
>
>  	brelse(bh);
>
>

Sunil Mushran Wrote:
> Wondering whether this id needs to be endian consistent.
> For failover nfs setups maybe.
IMHO, It is. Because osb->uuid_hash is fetched by:
        osb->uuid_hash = le32_to_cpu(di->id2.i_super.s_uuid_hash);
CMIIW, It should work in nfs failover.
> 
> Coly Li wrote:
>> Currently f_fsid of struct kstatfs returned from ocfs2_statfs() is
>> undefined (at least it should be
>> filled with 0). Since in some conditions, f_fsid value might be used
>> as (f_fsid, ino) pare to
>> uniquely identify a file, ocfs2 should return a defined unique f_fsid
>> value from ocfs2_statfs().
>>
>> This patch uses uuid_hash as a unique ID to initiate f_fsid value, the
>> 32bits width is enough for
>> ocfs2 membership so far.
>>
>> Signed-off-by: Coly Li <coly.li at suse.de>
>> ---
>>  fs/ocfs2/super.c |    2 ++
>>  1 files changed, 2 insertions(+), 0 deletions(-)
>>
>> diff --git a/fs/ocfs2/super.c b/fs/ocfs2/super.c
>> index 43ed113..fdab98a 100644
>> --- a/fs/ocfs2/super.c
>> +++ b/fs/ocfs2/super.c
>> @@ -1425,6 +1425,8 @@ static int ocfs2_statfs(struct dentry *dentry,
>> struct kstatfs *buf)
>>      buf->f_bavail = buf->f_bfree;
>>      buf->f_files = numbits;
>>      buf->f_ffree = freebits;
>> +    buf->f_fsid.val[0] = osb->uuid_hash & 0xFFFFFFFFUL;
>> +    buf->f_fsid.val[1] = 0;
>>
>>      brelse(bh);
>>
>>   
> 
-- 
Coly Li
SuSE Labs