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Ocfs2: Add new OCFS2_IOC_INFO ioctl for ocfs2 v8.

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The reason why we need this ioctl is to offer the none-privileged
end-user a possibility to get filesys info gathering.

We use OCFS2_IOC_INFO to manipulate the new ioctl, userspace passes a
structure to kernel containing an array of request pointers and request
count, such as,

* From userspace:

struct ocfs2_info_blocksize oib = {
        .ib_req = {
                .ir_magic = OCFS2_INFO_MAGIC,
                .ir_code = OCFS2_INFO_BLOCKSIZE,
                ...
        }
        ...
}

struct ocfs2_info_clustersize oic = {
        ...
}

uint64_t reqs[2] = {(unsigned long)&oib,
                    (unsigned long)&oic};

struct ocfs2_info info = {
        .oi_requests = reqs,
        .oi_count = 2,
}

ret = ioctl(fd, OCFS2_IOC_INFO, &info);

* In kernel:

Get the request pointers from *info*, then handle each request one bye one.

Idea here is to make the spearated request small enough to guarantee
a better backward&forward compatibility since a small piece of request
would be less likely to be broken if filesys on raw disk get changed.

Currently, the following 7 requests are supported per the requirement from
userspace tool o2info, and I believe it will grow over time:-)

        OCFS2_INFO_CLUSTERSIZE
        OCFS2_INFO_BLOCKSIZE
        OCFS2_INFO_MAXSLOTS
        OCFS2_INFO_LABEL
        OCFS2_INFO_UUID
        OCFS2_INFO_FS_FEATURES
        OCFS2_INFO_JOURNAL_SIZE

This ioctl is only specific to OCFS2.

Signed-off-by: Tristan Ye <tristan.ye@oracle.com>
Signed-off-by: Joel Becker <joel.becker@oracle.com>
This commit is contained in:
Tristan Ye
2010-05-22 16:26:33 +08:00
committed by Joel Becker
parent 152831be91
commit ddee5cdb70
2 changed files with 451 additions and 0 deletions
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95
fs/ocfs2/ocfs2_ioctl.h
View File

@@ -76,4 +76,99 @@ struct reflink_arguments {
};
#define OCFS2_IOC_REFLINK _IOW('o', 4, struct reflink_arguments)
/* Following definitions dedicated for ocfs2_info_request ioctls. */
#define OCFS2_INFO_MAX_REQUEST (50)
#define OCFS2_TEXT_UUID_LEN (OCFS2_VOL_UUID_LEN * 2)
/* Magic number of all requests */
#define OCFS2_INFO_MAGIC (0x4F32494E)
/*
* Always try to separate info request into small pieces to
* guarantee the backward&forward compatibility.
*/
struct ocfs2_info {
__u64 oi_requests; /* Array of __u64 pointers to requests */
__u32 oi_count; /* Number of requests in info_requests */
__u32 oi_pad;
};
struct ocfs2_info_request {
/*00*/ __u32 ir_magic; /* Magic number */
__u32 ir_code; /* Info request code */
__u32 ir_size; /* Size of request */
__u32 ir_flags; /* Request flags */
/*10*/ /* Request specific fields */
};
struct ocfs2_info_clustersize {
struct ocfs2_info_request ic_req;
__u32 ic_clustersize;
__u32 ic_pad;
};
struct ocfs2_info_blocksize {
struct ocfs2_info_request ib_req;
__u32 ib_blocksize;
__u32 ib_pad;
};
struct ocfs2_info_maxslots {
struct ocfs2_info_request im_req;
__u32 im_max_slots;
__u32 im_pad;
};
struct ocfs2_info_label {
struct ocfs2_info_request il_req;
__u8 il_label[OCFS2_MAX_VOL_LABEL_LEN];
} __attribute__ ((packed));
struct ocfs2_info_uuid {
struct ocfs2_info_request iu_req;
__u8 iu_uuid_str[OCFS2_TEXT_UUID_LEN + 1];
} __attribute__ ((packed));
struct ocfs2_info_fs_features {
struct ocfs2_info_request if_req;
__u32 if_compat_features;
__u32 if_incompat_features;
__u32 if_ro_compat_features;
__u32 if_pad;
};
struct ocfs2_info_journal_size {
struct ocfs2_info_request ij_req;
__u64 ij_journal_size;
};
/* Codes for ocfs2_info_request */
enum ocfs2_info_type {
OCFS2_INFO_CLUSTERSIZE = 1,
OCFS2_INFO_BLOCKSIZE,
OCFS2_INFO_MAXSLOTS,
OCFS2_INFO_LABEL,
OCFS2_INFO_UUID,
OCFS2_INFO_FS_FEATURES,
OCFS2_INFO_JOURNAL_SIZE,
OCFS2_INFO_NUM_TYPES
};
/* Flags for struct ocfs2_info_request */
/* Filled by the caller */
#define OCFS2_INFO_FL_NON_COHERENT (0x00000001) /* Cluster coherency not
required. This is a hint.
It is up to ocfs2 whether
the request can be fulfilled
without locking. */
/* Filled by ocfs2 */
#define OCFS2_INFO_FL_FILLED (0x40000000) /* Filesystem understood
this request and
filled in the answer */
#define OCFS2_INFO_FL_ERROR (0x80000000) /* Error happened during
request handling. */
#define OCFS2_IOC_INFO _IOR('o', 5, struct ocfs2_info)
#endif /* OCFS2_IOCTL_H */