Ocfs2: Add new OCFS2_IOC_INFO ioctl for ocfs2 v8.
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>
diff --git a/fs/ocfs2/ocfs2_ioctl.h b/fs/ocfs2/ocfs2_ioctl.h
index 2d3420a..9bc5354 100644
--- a/fs/ocfs2/ocfs2_ioctl.h
+++ b/fs/ocfs2/ocfs2_ioctl.h
@@ -76,4 +76,99 @@
};
#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 */