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Tristan Ye

2010-Apr-19 11:00 UTC

[Ocfs2-devel] [PATCH 1/1] Ocfs2: Add new OCFS2_IOC_INFO ioctl for ocfs2 v7.

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, following 8 ioctls get implemented 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

This ioctl is only specific to OCFS2.

Signed-off-by: Tristan Ye <tristan.ye at oracle.com>
---
 fs/ocfs2/ioctl.c       |  281 ++++++++++++++++++++++++++++++++++++++++++++++++
 fs/ocfs2/ocfs2_ioctl.h |   81 ++++++++++++++
 2 files changed, 362 insertions(+), 0 deletions(-)

diff --git a/fs/ocfs2/ioctl.c b/fs/ocfs2/ioctl.c
index 7d9d9c1..930e3ba 100644
--- a/fs/ocfs2/ioctl.c
+++ b/fs/ocfs2/ioctl.c
@@ -23,8 +23,13 @@
 #include "ioctl.h"
 #include "resize.h"
 #include "refcounttree.h"
+#include "sysfile.h"
+#include "buffer_head_io.h"
+#include "suballoc.h"
+
 
 #include <linux/ext2_fs.h>
+#include <linux/compat.h>
 
 static int ocfs2_get_inode_attr(struct inode *inode, unsigned *flags)
 {
@@ -109,6 +114,268 @@ bail:
 	return status;
 }
 
+int ocfs2_info_handle_blocksize(struct inode *inode,
+				struct ocfs2_info_request __user *req)
+{
+	int status = -EFAULT;
+	struct ocfs2_info_blocksize oib;
+
+	if (copy_from_user(&oib, req, sizeof(struct ocfs2_info_blocksize)))
+		goto bail;
+
+	oib.ib_blocksize = inode->i_sb->s_blocksize;
+	oib.ib_req.ir_flags |= OCFS2_INFO_FL_FILLED;
+
+	if (copy_to_user((struct ocfs2_info_blocksize __user *)req, &oib,
+			 sizeof(struct ocfs2_info_blocksize)))
+		goto bail;
+
+	status = 0;
+bail:
+	return status;
+}
+
+int ocfs2_info_handle_clustersize(struct inode *inode,
+				  struct ocfs2_info_request __user *req)
+{
+	int status = -EFAULT;
+	struct ocfs2_info_clustersize oic;
+	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
+
+	if (copy_from_user(&oic, req, sizeof(struct ocfs2_info_clustersize)))
+		goto bail;
+
+	oic.ic_clustersize = osb->s_clustersize;
+	oic.ic_req.ir_flags |= OCFS2_INFO_FL_FILLED;
+
+	if (copy_to_user((struct ocfs2_info_clustersize __user *)req, &oic,
+			 sizeof(struct ocfs2_info_clustersize)))
+		goto bail;
+	
+	status = 0;
+bail:
+	return status;
+}
+
+int ocfs2_info_handle_maxslots(struct inode *inode,
+			       struct ocfs2_info_request __user *req)
+{
+	int status = -EFAULT;
+	struct ocfs2_info_maxslots ois;
+	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
+
+	if (copy_from_user(&ois, req, sizeof(struct ocfs2_info_maxslots)))
+		goto bail;
+
+	ois.is_max_slots = osb->max_slots;
+	ois.is_req.ir_flags |= OCFS2_INFO_FL_FILLED;
+
+	if (copy_to_user((struct ocfs2_info_maxslots __user *)req, &ois,
+			 sizeof(struct ocfs2_info_maxslots)))
+		goto bail;
+
+	status = 0;
+bail:
+	return status;
+}
+
+int ocfs2_info_handle_label(struct inode *inode,
+			    struct ocfs2_info_request __user *req)
+{
+	int status = -EFAULT;
+	struct ocfs2_info_label oil;
+	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
+
+	if (copy_from_user(&oil, req, sizeof(struct ocfs2_info_label)))
+		goto bail;
+
+	memcpy(oil.il_label, osb->vol_label, OCFS2_MAX_VOL_LABEL_LEN);
+	oil.il_req.ir_flags |= OCFS2_INFO_FL_FILLED;
+
+	if (copy_to_user((struct ocfs2_info_label __user *)req, &oil,
+			 sizeof(struct ocfs2_info_label)))
+		goto bail;
+
+	status = 0;
+bail:
+	return status;
+}
+
+int ocfs2_info_handle_uuid(struct inode *inode,
+			   struct ocfs2_info_request __user *req)
+{
+	int status = -EFAULT;
+	struct ocfs2_info_uuid oiu;
+	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
+
+	if (copy_from_user(&oiu, req, sizeof(struct ocfs2_info_uuid)))
+		goto bail;
+
+	memcpy(oiu.iu_uuid_str, osb->uuid_str, OCFS2_INFO_VOL_UUIDSTR_LEN);
+	oiu.iu_req.ir_flags |= OCFS2_INFO_FL_FILLED;
+
+	if (copy_to_user((struct ocfs2_info_uuid __user *)req, &oiu,
+			 sizeof(struct ocfs2_info_uuid)))
+		goto bail;
+
+	status = 0;
+bail:
+	return status;
+}
+
+int ocfs2_info_handle_fs_features(struct inode *inode,
+				  struct ocfs2_info_request __user *req)
+{
+	int status = -EFAULT;
+	struct ocfs2_info_fs_features oif;
+	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
+
+	if (copy_from_user(&oif, req, sizeof(struct ocfs2_info_fs_features)))
+		goto bail;
+
+	oif.if_compat_features = osb->s_feature_compat;
+	oif.if_incompat_features = osb->s_feature_incompat;
+	oif.if_ro_compat_features = osb->s_feature_ro_compat;
+	oif.if_req.ir_flags |= OCFS2_INFO_FL_FILLED;
+
+	if (copy_to_user((struct ocfs2_info_fs_features __user *)req, &oif,
+			 sizeof(struct ocfs2_info_fs_features)))
+		goto bail;
+
+	status = 0;
+bail:
+	return status;
+}
+
+int ocfs2_info_handle_unknown(struct inode *inode,
+			      struct ocfs2_info_request __user *req)
+{
+	int status = -EFAULT;
+	struct ocfs2_info_request oir;
+
+	if (copy_from_user(&oir, req, sizeof(struct ocfs2_info_request)))
+		goto bail;
+
+	oir.ir_flags &= ~OCFS2_INFO_FL_FILLED;
+
+	if (copy_to_user(req, &oir, sizeof(struct ocfs2_info_request)))
+		goto bail;
+
+	status = 0;
+bail:
+	return status;
+}
+
+int ocfs2_info_handle_request(struct inode *inode,
+			      struct ocfs2_info_request __user *req)
+{
+	int status = 0;
+	struct ocfs2_info_request oir;
+
+	if (copy_from_user(&oir, req, sizeof(struct ocfs2_info_request))) {
+		status = -EFAULT;
+		goto bail;
+	}
+
+	if (oir.ir_magic != OCFS2_INFO_MAGIC) {
+		status = -EINVAL;
+		goto bail;
+	}
+
+	switch (oir.ir_code) {
+	case OCFS2_INFO_BLOCKSIZE:
+		if (oir.ir_size != sizeof(struct ocfs2_info_blocksize)) {
+			status = -EINVAL;
+			goto bail;
+		}
+		status = ocfs2_info_handle_blocksize(inode, req);
+		break;
+	case OCFS2_INFO_CLUSTERSIZE:
+		if (oir.ir_size != sizeof(struct ocfs2_info_clustersize)) {
+			status = -EINVAL;
+			goto bail;
+		}
+		status = ocfs2_info_handle_clustersize(inode, req);
+		break;
+	case OCFS2_INFO_MAXSLOTS:
+		if (oir.ir_size != sizeof(struct ocfs2_info_maxslots)) {
+			status = -EINVAL;
+			goto bail;
+		}
+		status = ocfs2_info_handle_maxslots(inode, req);
+		break;
+	case OCFS2_INFO_LABEL:
+		if (oir.ir_size != sizeof(struct ocfs2_info_label)) {
+			status = -EINVAL;
+			goto bail;
+		}
+		status = ocfs2_info_handle_label(inode, req);
+		break;
+	case OCFS2_INFO_UUID:
+		if (oir.ir_size != sizeof(struct ocfs2_info_uuid)) {
+			status = -EINVAL;
+			goto bail;
+		}
+		status = ocfs2_info_handle_uuid(inode, req);
+		break;
+	case OCFS2_INFO_FS_FEATURES:
+		if (oir.ir_size != sizeof(struct ocfs2_info_fs_features)) {
+			status = -EINVAL;
+			goto bail;
+		}
+		status = ocfs2_info_handle_fs_features(inode, req);
+		break;
+	default:
+		status = ocfs2_info_handle_unknown(inode, req);
+		break;
+	}
+
+bail:
+	mlog_exit(status);
+	return status;
+}
+
+int ocfs2_info_handle(struct inode *inode, struct ocfs2_info *info,
+		      int compat_flag)
+{
+	int i, status = 0;
+	u64 req_addr;
+	struct ocfs2_info_request __user *reqp;
+
+	if ((info->oi_count > OCFS2_INFO_MAX_REQUEST) ||
+	    (!info->oi_requests)) {
+		status = -EINVAL;
+		goto bail;
+	}
+
+	for (i = 0; i < info->oi_count; i++) {
+		status = -EFAULT;
+		if (compat_flag) {
+			if (get_user(req_addr,
+			     (u64 __user *)compat_ptr(info->oi_requests) + i))
+				goto bail;
+		} else {
+			if (get_user(req_addr,
+				     (u64 __user *)(info->oi_requests) + i))
+				goto bail;
+		}
+
+		reqp = (struct ocfs2_info_request *)req_addr;
+		if (!reqp) {
+			status = -EINVAL;
+			goto bail;
+		}
+
+		status = ocfs2_info_handle_request(inode, reqp);
+		if (status)
+			goto bail;
+	}
+
+bail:
+	mlog_exit(status);
+	return status;
+}
+
 long ocfs2_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 {
 	struct inode *inode = filp->f_path.dentry->d_inode;
@@ -120,6 +387,7 @@ long ocfs2_ioctl(struct file *filp, unsigned int cmd,
unsigned long arg)
 	struct reflink_arguments args;
 	const char *old_path, *new_path;
 	bool preserve;
+	struct ocfs2_info info;
 
 	switch (cmd) {
 	case OCFS2_IOC_GETFLAGS:
@@ -174,6 +442,12 @@ long ocfs2_ioctl(struct file *filp, unsigned int cmd,
unsigned long arg)
 		preserve = (args.preserve != 0);
 
 		return ocfs2_reflink_ioctl(inode, old_path, new_path, preserve);
+	case OCFS2_IOC_INFO:
+		if (copy_from_user(&info, (struct ocfs2_info __user *)arg,
+				   sizeof(struct ocfs2_info)))
+			return -EFAULT;
+
+		return ocfs2_info_handle(inode, &info, 0);
 	default:
 		return -ENOTTY;
 	}
@@ -185,6 +459,7 @@ long ocfs2_compat_ioctl(struct file *file, unsigned cmd,
unsigned long arg)
 	bool preserve;
 	struct reflink_arguments args;
 	struct inode *inode = file->f_path.dentry->d_inode;
+	struct ocfs2_info info;
 
 	switch (cmd) {
 	case OCFS2_IOC32_GETFLAGS:
@@ -209,6 +484,12 @@ long ocfs2_compat_ioctl(struct file *file, unsigned cmd,
unsigned long arg)
 
 		return ocfs2_reflink_ioctl(inode, compat_ptr(args.old_path),
 					   compat_ptr(args.new_path), preserve);
+	case OCFS2_IOC_INFO:
+		if (copy_from_user(&info, (struct ocfs2_info __user *)arg,
+				   sizeof(struct ocfs2_info)))
+			return -EFAULT;
+
+		return ocfs2_info_handle(inode, &info, 1);
 	default:
 		return -ENOIOCTLCMD;
 	}
diff --git a/fs/ocfs2/ocfs2_ioctl.h b/fs/ocfs2/ocfs2_ioctl.h
index 2d3420a..50f237a 100644
--- a/fs/ocfs2/ocfs2_ioctl.h
+++ b/fs/ocfs2/ocfs2_ioctl.h
@@ -76,4 +76,85 @@ struct reflink_arguments {
 };
 #define OCFS2_IOC_REFLINK	_IOW('o', 4, struct reflink_arguments)
 
+/* Following definitions dedicated for ocfs2_info_request ioctls. */
+#define OCFS2_INFO_VOL_UUIDSTR_LEN	(OCFS2_VOL_UUID_LEN * 2 + 1)
+#define OCFS2_INFO_MAX_REQUEST		(50)
+
+/* 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 */
+};
+
+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;
+};
+
+struct ocfs2_info_blocksize {
+	struct ocfs2_info_request ib_req;
+	__u32 ib_blocksize;
+};
+
+struct ocfs2_info_maxslots {
+	struct ocfs2_info_request is_req;
+	__u16 is_max_slots;
+};
+
+struct ocfs2_info_label {
+	struct ocfs2_info_request il_req;
+	__u8	il_label[OCFS2_MAX_VOL_LABEL_LEN];
+};
+
+struct ocfs2_info_uuid {
+	struct ocfs2_info_request iu_req;
+	__u8	iu_uuid_str[OCFS2_INFO_VOL_UUIDSTR_LEN];
+};
+
+struct ocfs2_info_fs_features {
+	struct ocfs2_info_request if_req;
+	__u32 if_compat_features;
+	__u32 if_incompat_features;
+	__u32 if_ro_compat_features;
+};
+
+/* 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_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		(0x80000000)	/* Filesystem understood
+							   this request and
+							   filled in the answer */
+
+#define OCFS2_IOC_INFO		_IOR('o', 5, struct ocfs2_info)
+
 #endif /* OCFS2_IOCTL_H */
-- 
1.5.5

Sunil Mushran

2010-Apr-19 20:16 UTC

head link

[Ocfs2-devel] [PATCH 1/1] Ocfs2: Add new OCFS2_IOC_INFO ioctl for ocfs2 v7.

Much better. Comments inlined.

Tristan Ye wrote:> 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);
>   

Can you add this description atop ocfs2_info_handle() too.

> * 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, following 8 ioctls get implemented 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
>
> This ioctl is only specific to OCFS2.
>
> Signed-off-by: Tristan Ye <tristan.ye at oracle.com>
> ---
>  fs/ocfs2/ioctl.c       |  281
++++++++++++++++++++++++++++++++++++++++++++++++
>  fs/ocfs2/ocfs2_ioctl.h |   81 ++++++++++++++
>  2 files changed, 362 insertions(+), 0 deletions(-)
>
> diff --git a/fs/ocfs2/ioctl.c b/fs/ocfs2/ioctl.c
> index 7d9d9c1..930e3ba 100644
> --- a/fs/ocfs2/ioctl.c
> +++ b/fs/ocfs2/ioctl.c
> @@ -23,8 +23,13 @@
>  #include "ioctl.h"
>  #include "resize.h"
>  #include "refcounttree.h"
> +#include "sysfile.h"
> +#include "buffer_head_io.h"
> +#include "suballoc.h"
> +
>  
>  #include <linux/ext2_fs.h>
> +#include <linux/compat.h>
>  
>  static int ocfs2_get_inode_attr(struct inode *inode, unsigned *flags)
>  {
> @@ -109,6 +114,268 @@ bail:
>  	return status;
>  }
>  
> +int ocfs2_info_handle_blocksize(struct inode *inode,
> +				struct ocfs2_info_request __user *req)
> +{
> +	int status = -EFAULT;
> +	struct ocfs2_info_blocksize oib;
> +
> +	if (copy_from_user(&oib, req, sizeof(struct ocfs2_info_blocksize)))
> +		goto bail;
> +
> +	oib.ib_blocksize = inode->i_sb->s_blocksize;
> +	oib.ib_req.ir_flags |= OCFS2_INFO_FL_FILLED;
> +
> +	if (copy_to_user((struct ocfs2_info_blocksize __user *)req, &oib,
> +			 sizeof(struct ocfs2_info_blocksize)))
> +		goto bail;
> +
> +	status = 0;
> +bail:
> +	return status;
> +}
>   
Why not use the error code returned by copy_from/to?

+ int status;
+ struct ocfs2_info_blocksize oib;
+
+ status = o2info_copy_from_user(oib, req);
+ if (!status) {
+ oib.ib_blocksize = inode->i_sb->s_blocksize;
+ oib.ib_req.ir_flags |= OCFS2_INFO_FL_FILLED;
+ status = o2info_copy_to_user(oib, req);
+ }
+
+ return status;
> +
> +int ocfs2_info_handle_clustersize(struct inode *inode,
> +				  struct ocfs2_info_request __user *req)
> +{
> +	int status = -EFAULT;
> +	struct ocfs2_info_clustersize oic;
> +	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
> +
> +	if (copy_from_user(&oic, req, sizeof(struct ocfs2_info_clustersize)))
> +		goto bail;
> +
> +	oic.ic_clustersize = osb->s_clustersize;
> +	oic.ic_req.ir_flags |= OCFS2_INFO_FL_FILLED;
> +
> +	if (copy_to_user((struct ocfs2_info_clustersize __user *)req, &oic,
> +			 sizeof(struct ocfs2_info_clustersize)))
> +		goto bail;
> +	
> +	status = 0;
> +bail:
> +	return status;
> +}
> +
> +int ocfs2_info_handle_maxslots(struct inode *inode,
> +			       struct ocfs2_info_request __user *req)
> +{
> +	int status = -EFAULT;
> +	struct ocfs2_info_maxslots ois;
> +	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
> +
> +	if (copy_from_user(&ois, req, sizeof(struct ocfs2_info_maxslots)))
> +		goto bail;
> +
> +	ois.is_max_slots = osb->max_slots;
> +	ois.is_req.ir_flags |= OCFS2_INFO_FL_FILLED;
> +
> +	if (copy_to_user((struct ocfs2_info_maxslots __user *)req, &ois,
> +			 sizeof(struct ocfs2_info_maxslots)))
> +		goto bail;
> +
> +	status = 0;
> +bail:
> +	return status;
> +}
> +
> +int ocfs2_info_handle_label(struct inode *inode,
> +			    struct ocfs2_info_request __user *req)
> +{
> +	int status = -EFAULT;
> +	struct ocfs2_info_label oil;
> +	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
> +
> +	if (copy_from_user(&oil, req, sizeof(struct ocfs2_info_label)))
> +		goto bail;
> +
> +	memcpy(oil.il_label, osb->vol_label, OCFS2_MAX_VOL_LABEL_LEN);
> +	oil.il_req.ir_flags |= OCFS2_INFO_FL_FILLED;
> +
> +	if (copy_to_user((struct ocfs2_info_label __user *)req, &oil,
> +			 sizeof(struct ocfs2_info_label)))
> +		goto bail;
> +
> +	status = 0;
> +bail:
> +	return status;
> +}
> +
> +int ocfs2_info_handle_uuid(struct inode *inode,
> +			   struct ocfs2_info_request __user *req)
> +{
> +	int status = -EFAULT;
> +	struct ocfs2_info_uuid oiu;
> +	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
> +
> +	if (copy_from_user(&oiu, req, sizeof(struct ocfs2_info_uuid)))
> +		goto bail;
> +
> +	memcpy(oiu.iu_uuid_str, osb->uuid_str, OCFS2_INFO_VOL_UUIDSTR_LEN);
> +	oiu.iu_req.ir_flags |= OCFS2_INFO_FL_FILLED;
> +
> +	if (copy_to_user((struct ocfs2_info_uuid __user *)req, &oiu,
> +			 sizeof(struct ocfs2_info_uuid)))
> +		goto bail;
> +
> +	status = 0;
> +bail:
> +	return status;
> +}
> +
> +int ocfs2_info_handle_fs_features(struct inode *inode,
> +				  struct ocfs2_info_request __user *req)
> +{
> +	int status = -EFAULT;
> +	struct ocfs2_info_fs_features oif;
> +	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
> +
> +	if (copy_from_user(&oif, req, sizeof(struct ocfs2_info_fs_features)))
> +		goto bail;
> +
> +	oif.if_compat_features = osb->s_feature_compat;
> +	oif.if_incompat_features = osb->s_feature_incompat;
> +	oif.if_ro_compat_features = osb->s_feature_ro_compat;
> +	oif.if_req.ir_flags |= OCFS2_INFO_FL_FILLED;
> +
> +	if (copy_to_user((struct ocfs2_info_fs_features __user *)req, &oif,
> +			 sizeof(struct ocfs2_info_fs_features)))
> +		goto bail;
> +
> +	status = 0;
> +bail:
> +	return status;
> +}
> +
> +int ocfs2_info_handle_unknown(struct inode *inode,
> +			      struct ocfs2_info_request __user *req)
> +{
> +	int status = -EFAULT;
> +	struct ocfs2_info_request oir;
> +
> +	if (copy_from_user(&oir, req, sizeof(struct ocfs2_info_request)))
> +		goto bail;
> +
> +	oir.ir_flags &= ~OCFS2_INFO_FL_FILLED;
> +
> +	if (copy_to_user(req, &oir, sizeof(struct ocfs2_info_request)))
> +		goto bail;
> +
> +	status = 0;
> +bail:
> +	return status;
> +}
> +
> +int ocfs2_info_handle_request(struct inode *inode,
> +			      struct ocfs2_info_request __user *req)
> +{
> +	int status = 0;
> +	struct ocfs2_info_request oir;
> +
> +	if (copy_from_user(&oir, req, sizeof(struct ocfs2_info_request))) {
> +		status = -EFAULT;
> +		goto bail;
> +	}
> +
> +	if (oir.ir_magic != OCFS2_INFO_MAGIC) {
> +		status = -EINVAL;
> +		goto bail;
> +	}
> +
>   
status = -EINVAL;
> +	switch (oir.ir_code) {
> +	case OCFS2_INFO_BLOCKSIZE:
> +		if (oir.ir_size != sizeof(struct ocfs2_info_blocksize)) {
> +			status = -EINVAL;
> +			goto bail;
> +		}
> +		status = ocfs2_info_handle_blocksize(inode, req);
> +		break;
>   
+	case OCFS2_INFO_BLOCKSIZE:
+		if (oir.ir_size == sizeof(struct ocfs2_info_blocksize))
+			status = ocfs2_info_handle_blocksize(inode, req);
+		break;

Do same below.

> +	case OCFS2_INFO_CLUSTERSIZE:
> +		if (oir.ir_size != sizeof(struct ocfs2_info_clustersize)) {
> +			status = -EINVAL;
> +			goto bail;
> +		}
> +		status = ocfs2_info_handle_clustersize(inode, req);
> +		break;
> +	case OCFS2_INFO_MAXSLOTS:
> +		if (oir.ir_size != sizeof(struct ocfs2_info_maxslots)) {
> +			status = -EINVAL;
> +			goto bail;
> +		}
> +		status = ocfs2_info_handle_maxslots(inode, req);
> +		break;
> +	case OCFS2_INFO_LABEL:
> +		if (oir.ir_size != sizeof(struct ocfs2_info_label)) {
> +			status = -EINVAL;
> +			goto bail;
> +		}
> +		status = ocfs2_info_handle_label(inode, req);
> +		break;
> +	case OCFS2_INFO_UUID:
> +		if (oir.ir_size != sizeof(struct ocfs2_info_uuid)) {
> +			status = -EINVAL;
> +			goto bail;
> +		}
> +		status = ocfs2_info_handle_uuid(inode, req);
> +		break;
> +	case OCFS2_INFO_FS_FEATURES:
> +		if (oir.ir_size != sizeof(struct ocfs2_info_fs_features)) {
> +			status = -EINVAL;
> +			goto bail;
> +		}
> +		status = ocfs2_info_handle_fs_features(inode, req);
> +		break;
> +	default:
> +		status = ocfs2_info_handle_unknown(inode, req);
> +		break;
> +	}
> +
> +bail:
> +	mlog_exit(status);
>   
No need for mlog.
> +	return status;
> +}
> +
> +int ocfs2_info_handle(struct inode *inode, struct ocfs2_info *info,
> +		      int compat_flag)
> +{
> +	int i, status = 0;
> +	u64 req_addr;
> +	struct ocfs2_info_request __user *reqp;
> +
> +	if ((info->oi_count > OCFS2_INFO_MAX_REQUEST) ||
> +	    (!info->oi_requests)) {
> +		status = -EINVAL;
> +		goto bail;
> +	}
> +
> +	for (i = 0; i < info->oi_count; i++) {
> +		status = -EFAULT;
> +		if (compat_flag) {
> +			if (get_user(req_addr,
> +			     (u64 __user *)compat_ptr(info->oi_requests) + i))
> +				goto bail;
> +		} else {
> +			if (get_user(req_addr,
> +				     (u64 __user *)(info->oi_requests) + i))
> +				goto bail;
> +		}
> +
> +		reqp = (struct ocfs2_info_request *)req_addr;
> +		if (!reqp) {
> +			status = -EINVAL;
> +			goto bail;
> +		}
> +
> +		status = ocfs2_info_handle_request(inode, reqp);
> +		if (status)
> +			goto bail;
> +	}
> +
> +bail:
> +	mlog_exit(status);
>   
Remove mlog.
> +	return status;
> +}
> +
>  long ocfs2_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
>  {
>  	struct inode *inode = filp->f_path.dentry->d_inode;
> @@ -120,6 +387,7 @@ long ocfs2_ioctl(struct file *filp, unsigned int cmd,
unsigned long arg)
>  	struct reflink_arguments args;
>  	const char *old_path, *new_path;
>  	bool preserve;
> +	struct ocfs2_info info;
>  
>  	switch (cmd) {
>  	case OCFS2_IOC_GETFLAGS:
> @@ -174,6 +442,12 @@ long ocfs2_ioctl(struct file *filp, unsigned int cmd,
unsigned long arg)
>  		preserve = (args.preserve != 0);
>  
>  		return ocfs2_reflink_ioctl(inode, old_path, new_path, preserve);
> +	case OCFS2_IOC_INFO:
> +		if (copy_from_user(&info, (struct ocfs2_info __user *)arg,
> +				   sizeof(struct ocfs2_info)))
> +			return -EFAULT;
> +
> +		return ocfs2_info_handle(inode, &info, 0);
>  	default:
>  		return -ENOTTY;
>  	}
> @@ -185,6 +459,7 @@ long ocfs2_compat_ioctl(struct file *file, unsigned
cmd, unsigned long arg)
>  	bool preserve;
>  	struct reflink_arguments args;
>  	struct inode *inode = file->f_path.dentry->d_inode;
> +	struct ocfs2_info info;
>  
>  	switch (cmd) {
>  	case OCFS2_IOC32_GETFLAGS:
> @@ -209,6 +484,12 @@ long ocfs2_compat_ioctl(struct file *file, unsigned
cmd, unsigned long arg)
>  
>  		return ocfs2_reflink_ioctl(inode, compat_ptr(args.old_path),
>  					   compat_ptr(args.new_path), preserve);
> +	case OCFS2_IOC_INFO:
> +		if (copy_from_user(&info, (struct ocfs2_info __user *)arg,
> +				   sizeof(struct ocfs2_info)))
> +			return -EFAULT;
> +
> +		return ocfs2_info_handle(inode, &info, 1);
>  	default:
>  		return -ENOIOCTLCMD;
>  	}
> diff --git a/fs/ocfs2/ocfs2_ioctl.h b/fs/ocfs2/ocfs2_ioctl.h
> index 2d3420a..50f237a 100644
> --- a/fs/ocfs2/ocfs2_ioctl.h
> +++ b/fs/ocfs2/ocfs2_ioctl.h
> @@ -76,4 +76,85 @@ struct reflink_arguments {
>  };
>  #define OCFS2_IOC_REFLINK	_IOW('o', 4, struct reflink_arguments)
>  
> +/* Following definitions dedicated for ocfs2_info_request ioctls. */
> +#define OCFS2_INFO_VOL_UUIDSTR_LEN	(OCFS2_VOL_UUID_LEN * 2 + 1)
> +#define OCFS2_INFO_MAX_REQUEST		(50)
> +
> +/* 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 */
> +};
> +
> +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;
> +};
> +
> +struct ocfs2_info_blocksize {
> +	struct ocfs2_info_request ib_req;
> +	__u32 ib_blocksize;
> +};
> +
> +struct ocfs2_info_maxslots {
> +	struct ocfs2_info_request is_req;
> +	__u16 is_max_slots;
> +};
> +
> +struct ocfs2_info_label {
> +	struct ocfs2_info_request il_req;
> +	__u8	il_label[OCFS2_MAX_VOL_LABEL_LEN];
> +};
> +
> +struct ocfs2_info_uuid {
> +	struct ocfs2_info_request iu_req;
> +	__u8	iu_uuid_str[OCFS2_INFO_VOL_UUIDSTR_LEN];
> +};
> +
> +struct ocfs2_info_fs_features {
> +	struct ocfs2_info_request if_req;
> +	__u32 if_compat_features;
> +	__u32 if_incompat_features;
> +	__u32 if_ro_compat_features;
> +};
> +
> +/* 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_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		(0x80000000)	/* Filesystem understood
> +							   this request and
> +							   filled in the answer */
> +
> +#define OCFS2_IOC_INFO		_IOR('o', 5, struct ocfs2_info)
> +
>  #endif /* OCFS2_IOCTL_H */
>

Tristan Ye

2010-Apr-26 12:17 UTC

head link

[Ocfs2-devel] [PATCH 1/1] Ocfs2: Add new OCFS2_IOC_INFO ioctl for ocfs2 v7.

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, following 8 ioctls get implemented 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

This ioctl is only specific to OCFS2.

Signed-off-by: Tristan Ye <tristan.ye at oracle.com>
---
 fs/ocfs2/ioctl.c       |  317 ++++++++++++++++++++++++++++++++++++++++++++++++
 fs/ocfs2/ocfs2_ioctl.h |   85 +++++++++++++
 2 files changed, 402 insertions(+), 0 deletions(-)

diff --git a/fs/ocfs2/ioctl.c b/fs/ocfs2/ioctl.c
index 7d9d9c1..e55e52d 100644
--- a/fs/ocfs2/ioctl.c
+++ b/fs/ocfs2/ioctl.c
@@ -23,8 +23,18 @@
 #include "ioctl.h"
 #include "resize.h"
 #include "refcounttree.h"
+#include "sysfile.h"
+#include "buffer_head_io.h"
+#include "suballoc.h"
+
 
 #include <linux/ext2_fs.h>
+#include <linux/compat.h>
+
+#define o2info_from_user(a, b)	\
+		copy_from_user(&(a), (b), sizeof(a))
+#define o2info_to_user(a, b)	\
+		copy_to_user((typeof(a) __user *)b, &(a), sizeof(a))
 
 static int ocfs2_get_inode_attr(struct inode *inode, unsigned *flags)
 {
@@ -109,6 +119,299 @@ bail:
 	return status;
 }
 
+int ocfs2_info_handle_blocksize(struct inode *inode,
+				struct ocfs2_info_request __user *req)
+{
+	int status = -EFAULT;
+	struct ocfs2_info_blocksize oib;
+
+	if (o2info_from_user(oib, req))
+		goto bail;
+
+	oib.ib_blocksize = inode->i_sb->s_blocksize;
+	oib.ib_req.ir_flags |= OCFS2_INFO_FL_FILLED;
+
+	if (o2info_to_user(oib, req))
+		goto bail;
+
+	status = 0;
+bail:
+	if (status) {
+		oib.ib_req.ir_flags |= OCFS2_INFO_FL_ERROR;
+		oib.ib_req.ir_error = status;
+	}
+
+	return status;
+}
+
+int ocfs2_info_handle_clustersize(struct inode *inode,
+				  struct ocfs2_info_request __user *req)
+{
+	int status = -EFAULT;
+	struct ocfs2_info_clustersize oic;
+	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
+
+	if (o2info_from_user(oic, req))
+		goto bail;
+
+	oic.ic_clustersize = osb->s_clustersize;
+	oic.ic_req.ir_flags |= OCFS2_INFO_FL_FILLED;
+
+	if (o2info_to_user(oic, req))
+		goto bail;
+
+	status = 0;
+bail:
+	if (status) {
+		oic.ic_req.ir_flags |= OCFS2_INFO_FL_ERROR;
+		oic.ic_req.ir_error = status;
+	}
+
+	return status;
+}
+
+int ocfs2_info_handle_maxslots(struct inode *inode,
+			       struct ocfs2_info_request __user *req)
+{
+	int status = -EFAULT;
+	struct ocfs2_info_maxslots oim;
+	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
+
+	if (o2info_from_user(oim, req))
+		goto bail;
+
+	oim.im_max_slots = osb->max_slots;
+	oim.im_req.ir_flags |= OCFS2_INFO_FL_FILLED;
+
+	if (o2info_to_user(oim, req))
+		goto bail;
+
+	status = 0;
+bail:
+	if (status) {
+		oim.im_req.ir_flags |= OCFS2_INFO_FL_ERROR;
+		oim.im_req.ir_error = status;
+	}
+
+	return status;
+}
+
+int ocfs2_info_handle_label(struct inode *inode,
+			    struct ocfs2_info_request __user *req)
+{
+	int status = -EFAULT;
+	struct ocfs2_info_label oil;
+	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
+
+	if (o2info_from_user(oil, req))
+		goto bail;
+
+	memcpy(oil.il_label, osb->vol_label, OCFS2_MAX_VOL_LABEL_LEN);
+	oil.il_req.ir_flags |= OCFS2_INFO_FL_FILLED;
+
+	if (o2info_to_user(oil, req))
+		goto bail;
+
+	status = 0;
+bail:
+	if (status) {
+		oil.il_req.ir_flags |= OCFS2_INFO_FL_ERROR;
+		oil.il_req.ir_error = status;
+	}
+
+	return status;
+}
+
+int ocfs2_info_handle_uuid(struct inode *inode,
+			   struct ocfs2_info_request __user *req)
+{
+	int status = -EFAULT;
+	struct ocfs2_info_uuid oiu;
+	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
+
+	if (o2info_from_user(oiu, req))
+		goto bail;
+
+	memcpy(oiu.iu_uuid_str, osb->uuid_str, OCFS2_TEXT_UUID_LEN + 1);
+	oiu.iu_req.ir_flags |= OCFS2_INFO_FL_FILLED;
+
+	if (o2info_to_user(oiu, req))
+		goto bail;
+
+	status = 0;
+bail:
+	if (status) {
+		oiu.iu_req.ir_flags |= OCFS2_INFO_FL_ERROR;
+		oiu.iu_req.ir_error = status;
+	}
+
+	return status;
+}
+
+int ocfs2_info_handle_fs_features(struct inode *inode,
+				  struct ocfs2_info_request __user *req)
+{
+	int status = -EFAULT;
+	struct ocfs2_info_fs_features oif;
+	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
+
+	if (o2info_from_user(oif, req))
+		goto bail;
+
+	oif.if_compat_features = osb->s_feature_compat;
+	oif.if_incompat_features = osb->s_feature_incompat;
+	oif.if_ro_compat_features = osb->s_feature_ro_compat;
+	oif.if_req.ir_flags |= OCFS2_INFO_FL_FILLED;
+
+	if (o2info_to_user(oif, req))
+		goto bail;
+
+	status = 0;
+bail:
+	if (status) {
+		oif.if_req.ir_flags |= OCFS2_INFO_FL_ERROR;
+		oif.if_req.ir_error = status;
+	}
+
+	return status;
+}
+
+int ocfs2_info_handle_unknown(struct inode *inode,
+			      struct ocfs2_info_request __user *req)
+{
+	int status = -EFAULT;
+	struct ocfs2_info_request oir;
+
+	if (o2info_from_user(oir, req))
+		goto bail;
+
+	oir.ir_flags &= ~OCFS2_INFO_FL_FILLED;
+
+	if (o2info_to_user(oir, req))
+		goto bail;
+
+	status = 0;
+bail:
+	if (status) {
+		oir.ir_flags |= OCFS2_INFO_FL_ERROR;
+		oir.ir_error = status;
+	}
+
+	return status;
+}
+
+/*
+ * Validate and distinguish OCFS2_IOC_INFO requests.
+ *
+ * - validate the magic number.
+ * - distinguish different requests.
+ * - validate size of different requests.
+ */
+int ocfs2_info_handle_request(struct inode *inode,
+			      struct ocfs2_info_request __user *req)
+{
+	int status = -EFAULT;
+	struct ocfs2_info_request oir;
+
+	if (o2info_from_user(oir, req))
+		goto bail;
+
+	status = -EINVAL;
+	if (oir.ir_magic != OCFS2_INFO_MAGIC)
+		goto bail;
+
+	switch (oir.ir_code) {
+	case OCFS2_INFO_BLOCKSIZE:
+		if (oir.ir_size == sizeof(struct ocfs2_info_blocksize))
+			status = ocfs2_info_handle_blocksize(inode, req);
+		break;
+	case OCFS2_INFO_CLUSTERSIZE:
+		if (oir.ir_size == sizeof(struct ocfs2_info_clustersize))
+			status = ocfs2_info_handle_clustersize(inode, req);
+		break;
+	case OCFS2_INFO_MAXSLOTS:
+		if (oir.ir_size == sizeof(struct ocfs2_info_maxslots))
+			status = ocfs2_info_handle_maxslots(inode, req);
+		break;
+	case OCFS2_INFO_LABEL:
+		if (oir.ir_size == sizeof(struct ocfs2_info_label))
+			status = ocfs2_info_handle_label(inode, req);
+		break;
+	case OCFS2_INFO_UUID:
+		if (oir.ir_size == sizeof(struct ocfs2_info_uuid))
+			status = ocfs2_info_handle_uuid(inode, req);
+		break;
+	case OCFS2_INFO_FS_FEATURES:
+		if (oir.ir_size == sizeof(struct ocfs2_info_fs_features))
+			status = ocfs2_info_handle_fs_features(inode, req);
+		break;
+	default:
+		status = ocfs2_info_handle_unknown(inode, req);
+		break;
+	}
+
+bail:
+	return status;
+}
+
+/*
+ * OCFS2_IOC_INFO handles an array of requests passed from userspace.
+ *
+ * ocfs2_info_handle() recevies a large info aggregation, grab and
+ * validate the request count from header, then break it into small
+ * pieces, later specific handlers can handle them one by one.
+ *
+ * Idea here is to make each separate request small enough to ensure
+ * a better backward&forward compatibility, since a small piece of
+ * request will be less likely to be broken if disk layout get changed.
+ */
+int ocfs2_info_handle(struct inode *inode, struct ocfs2_info *info,
+		      int compat_flag)
+{
+	int i, status = 0;
+	u64 req_addr;
+	struct ocfs2_info_request __user *reqp;
+
+	if ((info->oi_count > OCFS2_INFO_MAX_REQUEST) ||
+	    (!info->oi_requests)) {
+		status = -EINVAL;
+		goto bail;
+	}
+
+	for (i = 0; i < info->oi_count; i++) {
+		status = -EFAULT;
+		if (compat_flag) {
+			if (get_user(req_addr,
+			     (u64 __user *)compat_ptr(info->oi_requests) + i))
+				goto bail;
+		} else {
+			if (get_user(req_addr,
+				     (u64 __user *)(info->oi_requests) + i))
+				goto bail;
+		}
+
+		reqp = (struct ocfs2_info_request *)req_addr;
+		if (!reqp) {
+			status = -EINVAL;
+			goto bail;
+		}
+
+		status = ocfs2_info_handle_request(inode, reqp);
+	}
+
+	/*
+	 * Error of each request handling was kept separately inside
+	 * the request itself, ioctl(2) however will be responsible
+	 * for the error outside meaty request-filling operations.
+	 *
+	 * That way, all requests expect to be handled no matter error
+	 * occurs or not in request-handling body.
+	 */
+	status = 0;
+bail:
+	return status;
+}
+
 long ocfs2_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 {
 	struct inode *inode = filp->f_path.dentry->d_inode;
@@ -120,6 +423,7 @@ long ocfs2_ioctl(struct file *filp, unsigned int cmd,
unsigned long arg)
 	struct reflink_arguments args;
 	const char *old_path, *new_path;
 	bool preserve;
+	struct ocfs2_info info;
 
 	switch (cmd) {
 	case OCFS2_IOC_GETFLAGS:
@@ -174,6 +478,12 @@ long ocfs2_ioctl(struct file *filp, unsigned int cmd,
unsigned long arg)
 		preserve = (args.preserve != 0);
 
 		return ocfs2_reflink_ioctl(inode, old_path, new_path, preserve);
+	case OCFS2_IOC_INFO:
+		if (copy_from_user(&info, (struct ocfs2_info __user *)arg,
+				   sizeof(struct ocfs2_info)))
+			return -EFAULT;
+
+		return ocfs2_info_handle(inode, &info, 0);
 	default:
 		return -ENOTTY;
 	}
@@ -185,6 +495,7 @@ long ocfs2_compat_ioctl(struct file *file, unsigned cmd,
unsigned long arg)
 	bool preserve;
 	struct reflink_arguments args;
 	struct inode *inode = file->f_path.dentry->d_inode;
+	struct ocfs2_info info;
 
 	switch (cmd) {
 	case OCFS2_IOC32_GETFLAGS:
@@ -209,6 +520,12 @@ long ocfs2_compat_ioctl(struct file *file, unsigned cmd,
unsigned long arg)
 
 		return ocfs2_reflink_ioctl(inode, compat_ptr(args.old_path),
 					   compat_ptr(args.new_path), preserve);
+	case OCFS2_IOC_INFO:
+		if (copy_from_user(&info, (struct ocfs2_info __user *)arg,
+				   sizeof(struct ocfs2_info)))
+			return -EFAULT;
+
+		return ocfs2_info_handle(inode, &info, 1);
 	default:
 		return -ENOIOCTLCMD;
 	}
diff --git a/fs/ocfs2/ocfs2_ioctl.h b/fs/ocfs2/ocfs2_ioctl.h
index 2d3420a..4b922f3 100644
--- a/fs/ocfs2/ocfs2_ioctl.h
+++ b/fs/ocfs2/ocfs2_ioctl.h
@@ -76,4 +76,89 @@ 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 */
+};
+
+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 */
+	__u32 ir_error; /* Error code */
+/*14*/			/* Request specific fields */
+};
+
+struct ocfs2_info_clustersize {
+	struct ocfs2_info_request ic_req;
+	__u32 ic_clustersize;
+};
+
+struct ocfs2_info_blocksize {
+	struct ocfs2_info_request ib_req;
+	__u32 ib_blocksize;
+};
+
+struct ocfs2_info_maxslots {
+	struct ocfs2_info_request im_req;
+	__u16 im_max_slots;
+};
+
+struct ocfs2_info_label {
+	struct ocfs2_info_request il_req;
+	__u8	il_label[OCFS2_MAX_VOL_LABEL_LEN];
+};
+
+struct ocfs2_info_uuid {
+	struct ocfs2_info_request iu_req;
+	__u8	iu_uuid_str[OCFS2_TEXT_UUID_LEN + 1];
+};
+
+struct ocfs2_info_fs_features {
+	struct ocfs2_info_request if_req;
+	__u32 if_compat_features;
+	__u32 if_incompat_features;
+	__u32 if_ro_compat_features;
+};
+
+/* 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_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 */
-- 
1.5.5

Joel Becker

2010-May-06 01:05 UTC

head link

[Ocfs2-devel] [PATCH 1/1] Ocfs2: Add new OCFS2_IOC_INFO ioctl for ocfs2 v7.

On Mon, Apr 26, 2010 at 08:17:23PM +0800, Tristan Ye
wrote:> 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,
	You're going to hate us, but Sunil and I decided that the
complex error reporting was just too much for what should be a simple
query interface.  We think we should go back to the original, where any
error is returned, and the caller cannot trust any of the results unless
the call returns 0.  This means you don't need the ir_error field.  I
suppose you can keep the ERROR flag, as this can tell the caller which
request caused the error.

Joel

-- 

Life's Little Instruction Book #237

	"Seek out the good in people."

Joel Becker
Principal Software Developer
Oracle
E-mail: joel.becker at oracle.com
Phone: (650) 506-8127

Tristan Ye

2010-May-06 08:43 UTC

head link

[Ocfs2-devel] [PATCH 1/1] Ocfs2: Add new OCFS2_IOC_INFO ioctl for ocfs2 v7.

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, following 8 ioctls get implemented 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 at oracle.com>
---
 fs/ocfs2/ioctl.c       |  325 ++++++++++++++++++++++++++++++++++++++++++++++++
 fs/ocfs2/ocfs2_ioctl.h |   90 +++++++++++++
 2 files changed, 415 insertions(+), 0 deletions(-)

diff --git a/fs/ocfs2/ioctl.c b/fs/ocfs2/ioctl.c
index 7d9d9c1..5435a59 100644
--- a/fs/ocfs2/ioctl.c
+++ b/fs/ocfs2/ioctl.c
@@ -23,8 +23,18 @@
 #include "ioctl.h"
 #include "resize.h"
 #include "refcounttree.h"
+#include "sysfile.h"
+#include "buffer_head_io.h"
+#include "suballoc.h"
+
 
 #include <linux/ext2_fs.h>
+#include <linux/compat.h>
+
+#define o2info_from_user(a, b)	\
+		copy_from_user(&(a), (b), sizeof(a))
+#define o2info_to_user(a, b)	\
+		copy_to_user((typeof(a) __user *)b, &(a), sizeof(a))
 
 static int ocfs2_get_inode_attr(struct inode *inode, unsigned *flags)
 {
@@ -109,6 +119,307 @@ bail:
 	return status;
 }
 
+int ocfs2_info_handle_blocksize(struct inode *inode,
+				struct ocfs2_info_request __user *req)
+{
+	int status = -EFAULT;
+	struct ocfs2_info_blocksize oib;
+
+	if (o2info_from_user(oib, req))
+		goto bail;
+
+	oib.ib_blocksize = inode->i_sb->s_blocksize;
+	oib.ib_req.ir_flags |= OCFS2_INFO_FL_FILLED;
+
+	if (o2info_to_user(oib, req))
+		goto bail;
+
+	status = 0;
+bail:
+	if (status)
+		oib.ib_req.ir_flags |= OCFS2_INFO_FL_ERROR;
+
+	return status;
+}
+
+int ocfs2_info_handle_clustersize(struct inode *inode,
+				  struct ocfs2_info_request __user *req)
+{
+	int status = -EFAULT;
+	struct ocfs2_info_clustersize oic;
+	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
+
+	if (o2info_from_user(oic, req))
+		goto bail;
+
+	oic.ic_clustersize = osb->s_clustersize;
+	oic.ic_req.ir_flags |= OCFS2_INFO_FL_FILLED;
+
+	if (o2info_to_user(oic, req))
+		goto bail;
+
+	status = 0;
+bail:
+	if (status)
+		oic.ic_req.ir_flags |= OCFS2_INFO_FL_ERROR;
+
+	return status;
+}
+
+int ocfs2_info_handle_maxslots(struct inode *inode,
+			       struct ocfs2_info_request __user *req)
+{
+	int status = -EFAULT;
+	struct ocfs2_info_maxslots oim;
+	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
+
+	if (o2info_from_user(oim, req))
+		goto bail;
+
+	oim.im_max_slots = osb->max_slots;
+	oim.im_req.ir_flags |= OCFS2_INFO_FL_FILLED;
+
+	if (o2info_to_user(oim, req))
+		goto bail;
+
+	status = 0;
+bail:
+	if (status)
+		oim.im_req.ir_flags |= OCFS2_INFO_FL_ERROR;
+
+	return status;
+}
+
+int ocfs2_info_handle_label(struct inode *inode,
+			    struct ocfs2_info_request __user *req)
+{
+	int status = -EFAULT;
+	struct ocfs2_info_label oil;
+	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
+
+	if (o2info_from_user(oil, req))
+		goto bail;
+
+	memcpy(oil.il_label, osb->vol_label, OCFS2_MAX_VOL_LABEL_LEN);
+	oil.il_req.ir_flags |= OCFS2_INFO_FL_FILLED;
+
+	if (o2info_to_user(oil, req))
+		goto bail;
+
+	status = 0;
+bail:
+	if (status)
+		oil.il_req.ir_flags |= OCFS2_INFO_FL_ERROR;
+
+	return status;
+}
+
+int ocfs2_info_handle_uuid(struct inode *inode,
+			   struct ocfs2_info_request __user *req)
+{
+	int status = -EFAULT;
+	struct ocfs2_info_uuid oiu;
+	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
+
+	if (o2info_from_user(oiu, req))
+		goto bail;
+
+	memcpy(oiu.iu_uuid_str, osb->uuid_str, OCFS2_TEXT_UUID_LEN + 1);
+	oiu.iu_req.ir_flags |= OCFS2_INFO_FL_FILLED;
+
+	if (o2info_to_user(oiu, req))
+		goto bail;
+
+	status = 0;
+bail:
+	if (status)
+		oiu.iu_req.ir_flags |= OCFS2_INFO_FL_ERROR;
+
+	return status;
+}
+
+int ocfs2_info_handle_fs_features(struct inode *inode,
+				  struct ocfs2_info_request __user *req)
+{
+	int status = -EFAULT;
+	struct ocfs2_info_fs_features oif;
+	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
+
+	if (o2info_from_user(oif, req))
+		goto bail;
+
+	oif.if_compat_features = osb->s_feature_compat;
+	oif.if_incompat_features = osb->s_feature_incompat;
+	oif.if_ro_compat_features = osb->s_feature_ro_compat;
+	oif.if_req.ir_flags |= OCFS2_INFO_FL_FILLED;
+
+	if (o2info_to_user(oif, req))
+		goto bail;
+
+	status = 0;
+bail:
+	if (status)
+		oif.if_req.ir_flags |= OCFS2_INFO_FL_ERROR;
+
+	return status;
+}
+
+int ocfs2_info_handle_journal_size(struct inode *inode,
+				   struct ocfs2_info_request __user *req)
+{
+	int status = -EFAULT;
+	struct ocfs2_info_journal_size oij;
+	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
+
+	if (o2info_from_user(oij, req))
+		goto bail;
+
+	oij.ij_journal_size = osb->journal->j_inode->i_size;
+
+	oij.ij_req.ir_flags |= OCFS2_INFO_FL_FILLED;
+
+	if (o2info_to_user(oij, req))
+		goto bail;
+
+	status = 0;
+bail:
+	if (status)
+		oij.ij_req.ir_flags |= OCFS2_INFO_FL_ERROR;
+
+	return status;
+}
+
+int ocfs2_info_handle_unknown(struct inode *inode,
+			      struct ocfs2_info_request __user *req)
+{
+	int status = -EFAULT;
+	struct ocfs2_info_request oir;
+
+	if (o2info_from_user(oir, req))
+		goto bail;
+
+	oir.ir_flags &= ~OCFS2_INFO_FL_FILLED;
+
+	if (o2info_to_user(oir, req))
+		goto bail;
+
+	status = 0;
+bail:
+	if (status)
+		oir.ir_flags |= OCFS2_INFO_FL_ERROR;
+
+	return status;
+}
+
+/*
+ * Validate and distinguish OCFS2_IOC_INFO requests.
+ *
+ * - validate the magic number.
+ * - distinguish different requests.
+ * - validate size of different requests.
+ */
+int ocfs2_info_handle_request(struct inode *inode,
+			      struct ocfs2_info_request __user *req)
+{
+	int status = -EFAULT;
+	struct ocfs2_info_request oir;
+
+	if (o2info_from_user(oir, req))
+		goto bail;
+
+	status = -EINVAL;
+	if (oir.ir_magic != OCFS2_INFO_MAGIC)
+		goto bail;
+
+	switch (oir.ir_code) {
+	case OCFS2_INFO_BLOCKSIZE:
+		if (oir.ir_size == sizeof(struct ocfs2_info_blocksize))
+			status = ocfs2_info_handle_blocksize(inode, req);
+		break;
+	case OCFS2_INFO_CLUSTERSIZE:
+		if (oir.ir_size == sizeof(struct ocfs2_info_clustersize))
+			status = ocfs2_info_handle_clustersize(inode, req);
+		break;
+	case OCFS2_INFO_MAXSLOTS:
+		if (oir.ir_size == sizeof(struct ocfs2_info_maxslots))
+			status = ocfs2_info_handle_maxslots(inode, req);
+		break;
+	case OCFS2_INFO_LABEL:
+		if (oir.ir_size == sizeof(struct ocfs2_info_label))
+			status = ocfs2_info_handle_label(inode, req);
+		break;
+	case OCFS2_INFO_UUID:
+		if (oir.ir_size == sizeof(struct ocfs2_info_uuid))
+			status = ocfs2_info_handle_uuid(inode, req);
+		break;
+	case OCFS2_INFO_FS_FEATURES:
+		if (oir.ir_size == sizeof(struct ocfs2_info_fs_features))
+			status = ocfs2_info_handle_fs_features(inode, req);
+		break;
+	case OCFS2_INFO_JOURNAL_SIZE:
+		if (oir.ir_size == sizeof(struct ocfs2_info_journal_size))
+			status = ocfs2_info_handle_journal_size(inode, req);
+		break;
+	default:
+		status = ocfs2_info_handle_unknown(inode, req);
+		break;
+	}
+
+bail:
+	return status;
+}
+
+/*
+ * OCFS2_IOC_INFO handles an array of requests passed from userspace.
+ *
+ * ocfs2_info_handle() recevies a large info aggregation, grab and
+ * validate the request count from header, then break it into small
+ * pieces, later specific handlers can handle them one by one.
+ *
+ * Idea here is to make each separate request small enough to ensure
+ * a better backward&forward compatibility, since a small piece of
+ * request will be less likely to be broken if disk layout get changed.
+ */
+int ocfs2_info_handle(struct inode *inode, struct ocfs2_info *info,
+		      int compat_flag)
+{
+	int i, status = 0;
+	u64 req_addr;
+	struct ocfs2_info_request __user *reqp;
+
+	if ((info->oi_count > OCFS2_INFO_MAX_REQUEST) ||
+	    (!info->oi_requests)) {
+		status = -EINVAL;
+		goto bail;
+	}
+
+	for (i = 0; i < info->oi_count; i++) {
+		status = -EFAULT;
+		if (compat_flag) {
+			if (get_user(req_addr,
+			     (u64 __user *)compat_ptr(info->oi_requests) + i))
+				goto bail;
+		} else {
+			if (get_user(req_addr,
+				     (u64 __user *)(info->oi_requests) + i))
+				goto bail;
+		}
+
+		reqp = (struct ocfs2_info_request *)req_addr;
+		if (!reqp) {
+			status = -EINVAL;
+			goto bail;
+		}
+
+		status = ocfs2_info_handle_request(inode, reqp);
+		if (status)
+			goto bail;
+	}
+
+bail:
+	return status;
+}
+
 long ocfs2_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 {
 	struct inode *inode = filp->f_path.dentry->d_inode;
@@ -120,6 +431,7 @@ long ocfs2_ioctl(struct file *filp, unsigned int cmd,
unsigned long arg)
 	struct reflink_arguments args;
 	const char *old_path, *new_path;
 	bool preserve;
+	struct ocfs2_info info;
 
 	switch (cmd) {
 	case OCFS2_IOC_GETFLAGS:
@@ -174,6 +486,12 @@ long ocfs2_ioctl(struct file *filp, unsigned int cmd,
unsigned long arg)
 		preserve = (args.preserve != 0);
 
 		return ocfs2_reflink_ioctl(inode, old_path, new_path, preserve);
+	case OCFS2_IOC_INFO:
+		if (copy_from_user(&info, (struct ocfs2_info __user *)arg,
+				   sizeof(struct ocfs2_info)))
+			return -EFAULT;
+
+		return ocfs2_info_handle(inode, &info, 0);
 	default:
 		return -ENOTTY;
 	}
@@ -185,6 +503,7 @@ long ocfs2_compat_ioctl(struct file *file, unsigned cmd,
unsigned long arg)
 	bool preserve;
 	struct reflink_arguments args;
 	struct inode *inode = file->f_path.dentry->d_inode;
+	struct ocfs2_info info;
 
 	switch (cmd) {
 	case OCFS2_IOC32_GETFLAGS:
@@ -209,6 +528,12 @@ long ocfs2_compat_ioctl(struct file *file, unsigned cmd,
unsigned long arg)
 
 		return ocfs2_reflink_ioctl(inode, compat_ptr(args.old_path),
 					   compat_ptr(args.new_path), preserve);
+	case OCFS2_IOC_INFO:
+		if (copy_from_user(&info, (struct ocfs2_info __user *)arg,
+				   sizeof(struct ocfs2_info)))
+			return -EFAULT;
+
+		return ocfs2_info_handle(inode, &info, 1);
 	default:
 		return -ENOIOCTLCMD;
 	}
diff --git a/fs/ocfs2/ocfs2_ioctl.h b/fs/ocfs2/ocfs2_ioctl.h
index 2d3420a..74c7566 100644
--- a/fs/ocfs2/ocfs2_ioctl.h
+++ b/fs/ocfs2/ocfs2_ioctl.h
@@ -76,4 +76,94 @@ 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 */
+};
+
+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;
+};
+
+struct ocfs2_info_blocksize {
+	struct ocfs2_info_request ib_req;
+	__u32 ib_blocksize;
+};
+
+struct ocfs2_info_maxslots {
+	struct ocfs2_info_request im_req;
+	__u16 im_max_slots;
+};
+
+struct ocfs2_info_label {
+	struct ocfs2_info_request il_req;
+	__u8	il_label[OCFS2_MAX_VOL_LABEL_LEN];
+};
+
+struct ocfs2_info_uuid {
+	struct ocfs2_info_request iu_req;
+	__u8	iu_uuid_str[OCFS2_TEXT_UUID_LEN + 1];
+};
+
+struct ocfs2_info_fs_features {
+	struct ocfs2_info_request if_req;
+	__u32 if_compat_features;
+	__u32 if_incompat_features;
+	__u32 if_ro_compat_features;
+};
+
+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 */
-- 
1.5.5

Tristan Ye

2010-May-19 02:28 UTC

head link

[Ocfs2-devel] [PATCH 1/1] Ocfs2: Add new OCFS2_IOC_INFO ioctl for ocfs2 v7.

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 at oracle.com>
---
 fs/ocfs2/ioctl.c       |  340 ++++++++++++++++++++++++++++++++++++++++++++++++
 fs/ocfs2/ocfs2_ioctl.h |   90 +++++++++++++
 2 files changed, 430 insertions(+), 0 deletions(-)

diff --git a/fs/ocfs2/ioctl.c b/fs/ocfs2/ioctl.c
index 7d9d9c1..06b6f1c 100644
--- a/fs/ocfs2/ioctl.c
+++ b/fs/ocfs2/ioctl.c
@@ -23,8 +23,33 @@
 #include "ioctl.h"
 #include "resize.h"
 #include "refcounttree.h"
+#include "sysfile.h"
+#include "buffer_head_io.h"
+#include "suballoc.h"
+
 
 #include <linux/ext2_fs.h>
+#include <linux/compat.h>
+
+#define o2info_from_user(a, b)	\
+		copy_from_user(&(a), (b), sizeof(a))
+#define o2info_to_user(a, b)	\
+		copy_to_user((typeof(a) __user *)b, &(a), sizeof(a))
+
+/*
+ * This call is void because we are already reporting an error that may
+ * be -EFAULT.  The error will be returned from the ioctl(2) call.  It's
+ * just a best-effort to tell userspace that this request caused the error.
+ */
+static inline void __o2info_set_request_error(struct ocfs2_info_request *kreq,
+					struct ocfs2_info_request __user *req)
+{
+	kreq->ir_flags |= OCFS2_INFO_FL_ERROR;
+	(void)put_user(kreq->ir_flags, (__u32 __user *)&(req->ir_flags));
+}
+
+#define o2info_set_request_error(a, b) \
+		__o2info_set_request_error((struct ocfs2_info_request *)&(a), b)
 
 static int ocfs2_get_inode_attr(struct inode *inode, unsigned *flags)
 {
@@ -109,6 +134,307 @@ bail:
 	return status;
 }
 
+int ocfs2_info_handle_blocksize(struct inode *inode,
+				struct ocfs2_info_request __user *req)
+{
+	int status = -EFAULT;
+	struct ocfs2_info_blocksize oib;
+
+	if (o2info_from_user(oib, req))
+		goto bail;
+
+	oib.ib_blocksize = inode->i_sb->s_blocksize;
+	oib.ib_req.ir_flags |= OCFS2_INFO_FL_FILLED;
+
+	if (o2info_to_user(oib, req))
+		goto bail;
+
+	status = 0;
+bail:
+	if (status)
+		o2info_set_request_error(oib, req);
+
+	return status;
+}
+
+int ocfs2_info_handle_clustersize(struct inode *inode,
+				  struct ocfs2_info_request __user *req)
+{
+	int status = -EFAULT;
+	struct ocfs2_info_clustersize oic;
+	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
+
+	if (o2info_from_user(oic, req))
+		goto bail;
+
+	oic.ic_clustersize = osb->s_clustersize;
+	oic.ic_req.ir_flags |= OCFS2_INFO_FL_FILLED;
+
+	if (o2info_to_user(oic, req))
+		goto bail;
+
+	status = 0;
+bail:
+	if (status)
+		o2info_set_request_error(oic, req);
+
+	return status;
+}
+
+int ocfs2_info_handle_maxslots(struct inode *inode,
+			       struct ocfs2_info_request __user *req)
+{
+	int status = -EFAULT;
+	struct ocfs2_info_maxslots oim;
+	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
+
+	if (o2info_from_user(oim, req))
+		goto bail;
+
+	oim.im_max_slots = osb->max_slots;
+	oim.im_req.ir_flags |= OCFS2_INFO_FL_FILLED;
+
+	if (o2info_to_user(oim, req))
+		goto bail;
+
+	status = 0;
+bail:
+	if (status)
+		o2info_set_request_error(oim, req);
+
+	return status;
+}
+
+int ocfs2_info_handle_label(struct inode *inode,
+			    struct ocfs2_info_request __user *req)
+{
+	int status = -EFAULT;
+	struct ocfs2_info_label oil;
+	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
+
+	if (o2info_from_user(oil, req))
+		goto bail;
+
+	memcpy(oil.il_label, osb->vol_label, OCFS2_MAX_VOL_LABEL_LEN);
+	oil.il_req.ir_flags |= OCFS2_INFO_FL_FILLED;
+
+	if (o2info_to_user(oil, req))
+		goto bail;
+
+	status = 0;
+bail:
+	if (status)
+		o2info_set_request_error(oil, req);
+
+	return status;
+}
+
+int ocfs2_info_handle_uuid(struct inode *inode,
+			   struct ocfs2_info_request __user *req)
+{
+	int status = -EFAULT;
+	struct ocfs2_info_uuid oiu;
+	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
+
+	if (o2info_from_user(oiu, req))
+		goto bail;
+
+	memcpy(oiu.iu_uuid_str, osb->uuid_str, OCFS2_TEXT_UUID_LEN + 1);
+	oiu.iu_req.ir_flags |= OCFS2_INFO_FL_FILLED;
+
+	if (o2info_to_user(oiu, req))
+		goto bail;
+
+	status = 0;
+bail:
+	if (status)
+		o2info_set_request_error(oiu, req);
+
+	return status;
+}
+
+int ocfs2_info_handle_fs_features(struct inode *inode,
+				  struct ocfs2_info_request __user *req)
+{
+	int status = -EFAULT;
+	struct ocfs2_info_fs_features oif;
+	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
+
+	if (o2info_from_user(oif, req))
+		goto bail;
+
+	oif.if_compat_features = osb->s_feature_compat;
+	oif.if_incompat_features = osb->s_feature_incompat;
+	oif.if_ro_compat_features = osb->s_feature_ro_compat;
+	oif.if_req.ir_flags |= OCFS2_INFO_FL_FILLED;
+
+	if (o2info_to_user(oif, req))
+		goto bail;
+
+	status = 0;
+bail:
+	if (status)
+		o2info_set_request_error(oif, req);
+
+	return status;
+}
+
+int ocfs2_info_handle_journal_size(struct inode *inode,
+				   struct ocfs2_info_request __user *req)
+{
+	int status = -EFAULT;
+	struct ocfs2_info_journal_size oij;
+	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
+
+	if (o2info_from_user(oij, req))
+		goto bail;
+
+	oij.ij_journal_size = osb->journal->j_inode->i_size;
+
+	oij.ij_req.ir_flags |= OCFS2_INFO_FL_FILLED;
+
+	if (o2info_to_user(oij, req))
+		goto bail;
+
+	status = 0;
+bail:
+	if (status)
+		o2info_set_request_error(oij, req);
+
+	return status;
+}
+
+int ocfs2_info_handle_unknown(struct inode *inode,
+			      struct ocfs2_info_request __user *req)
+{
+	int status = -EFAULT;
+	struct ocfs2_info_request oir;
+
+	if (o2info_from_user(oir, req))
+		goto bail;
+
+	oir.ir_flags &= ~OCFS2_INFO_FL_FILLED;
+
+	if (o2info_to_user(oir, req))
+		goto bail;
+
+	status = 0;
+bail:
+	if (status)
+		o2info_set_request_error(oir, req);
+
+	return status;
+}
+
+/*
+ * Validate and distinguish OCFS2_IOC_INFO requests.
+ *
+ * - validate the magic number.
+ * - distinguish different requests.
+ * - validate size of different requests.
+ */
+int ocfs2_info_handle_request(struct inode *inode,
+			      struct ocfs2_info_request __user *req)
+{
+	int status = -EFAULT;
+	struct ocfs2_info_request oir;
+
+	if (o2info_from_user(oir, req))
+		goto bail;
+
+	status = -EINVAL;
+	if (oir.ir_magic != OCFS2_INFO_MAGIC)
+		goto bail;
+
+	switch (oir.ir_code) {
+	case OCFS2_INFO_BLOCKSIZE:
+		if (oir.ir_size == sizeof(struct ocfs2_info_blocksize))
+			status = ocfs2_info_handle_blocksize(inode, req);
+		break;
+	case OCFS2_INFO_CLUSTERSIZE:
+		if (oir.ir_size == sizeof(struct ocfs2_info_clustersize))
+			status = ocfs2_info_handle_clustersize(inode, req);
+		break;
+	case OCFS2_INFO_MAXSLOTS:
+		if (oir.ir_size == sizeof(struct ocfs2_info_maxslots))
+			status = ocfs2_info_handle_maxslots(inode, req);
+		break;
+	case OCFS2_INFO_LABEL:
+		if (oir.ir_size == sizeof(struct ocfs2_info_label))
+			status = ocfs2_info_handle_label(inode, req);
+		break;
+	case OCFS2_INFO_UUID:
+		if (oir.ir_size == sizeof(struct ocfs2_info_uuid))
+			status = ocfs2_info_handle_uuid(inode, req);
+		break;
+	case OCFS2_INFO_FS_FEATURES:
+		if (oir.ir_size == sizeof(struct ocfs2_info_fs_features))
+			status = ocfs2_info_handle_fs_features(inode, req);
+		break;
+	case OCFS2_INFO_JOURNAL_SIZE:
+		if (oir.ir_size == sizeof(struct ocfs2_info_journal_size))
+			status = ocfs2_info_handle_journal_size(inode, req);
+		break;
+	default:
+		status = ocfs2_info_handle_unknown(inode, req);
+		break;
+	}
+
+bail:
+	return status;
+}
+
+/*
+ * OCFS2_IOC_INFO handles an array of requests passed from userspace.
+ *
+ * ocfs2_info_handle() recevies a large info aggregation, grab and
+ * validate the request count from header, then break it into small
+ * pieces, later specific handlers can handle them one by one.
+ *
+ * Idea here is to make each separate request small enough to ensure
+ * a better backward&forward compatibility, since a small piece of
+ * request will be less likely to be broken if disk layout get changed.
+ */
+int ocfs2_info_handle(struct inode *inode, struct ocfs2_info *info,
+		      int compat_flag)
+{
+	int i, status = 0;
+	u64 req_addr;
+	struct ocfs2_info_request __user *reqp;
+
+	if ((info->oi_count > OCFS2_INFO_MAX_REQUEST) ||
+	    (!info->oi_requests)) {
+		status = -EINVAL;
+		goto bail;
+	}
+
+	for (i = 0; i < info->oi_count; i++) {
+		status = -EFAULT;
+		if (compat_flag) {
+			if (get_user(req_addr,
+			     (u64 __user *)compat_ptr(info->oi_requests) + i))
+				goto bail;
+		} else {
+			if (get_user(req_addr,
+				     (u64 __user *)(info->oi_requests) + i))
+				goto bail;
+		}
+
+		reqp = (struct ocfs2_info_request *)req_addr;
+		if (!reqp) {
+			status = -EINVAL;
+			goto bail;
+		}
+
+		status = ocfs2_info_handle_request(inode, reqp);
+		if (status)
+			break;
+	}
+
+bail:
+	return status;
+}
+
 long ocfs2_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 {
 	struct inode *inode = filp->f_path.dentry->d_inode;
@@ -120,6 +446,7 @@ long ocfs2_ioctl(struct file *filp, unsigned int cmd,
unsigned long arg)
 	struct reflink_arguments args;
 	const char *old_path, *new_path;
 	bool preserve;
+	struct ocfs2_info info;
 
 	switch (cmd) {
 	case OCFS2_IOC_GETFLAGS:
@@ -174,6 +501,12 @@ long ocfs2_ioctl(struct file *filp, unsigned int cmd,
unsigned long arg)
 		preserve = (args.preserve != 0);
 
 		return ocfs2_reflink_ioctl(inode, old_path, new_path, preserve);
+	case OCFS2_IOC_INFO:
+		if (copy_from_user(&info, (struct ocfs2_info __user *)arg,
+				   sizeof(struct ocfs2_info)))
+			return -EFAULT;
+
+		return ocfs2_info_handle(inode, &info, 0);
 	default:
 		return -ENOTTY;
 	}
@@ -185,6 +518,7 @@ long ocfs2_compat_ioctl(struct file *file, unsigned cmd,
unsigned long arg)
 	bool preserve;
 	struct reflink_arguments args;
 	struct inode *inode = file->f_path.dentry->d_inode;
+	struct ocfs2_info info;
 
 	switch (cmd) {
 	case OCFS2_IOC32_GETFLAGS:
@@ -209,6 +543,12 @@ long ocfs2_compat_ioctl(struct file *file, unsigned cmd,
unsigned long arg)
 
 		return ocfs2_reflink_ioctl(inode, compat_ptr(args.old_path),
 					   compat_ptr(args.new_path), preserve);
+	case OCFS2_IOC_INFO:
+		if (copy_from_user(&info, (struct ocfs2_info __user *)arg,
+				   sizeof(struct ocfs2_info)))
+			return -EFAULT;
+
+		return ocfs2_info_handle(inode, &info, 1);
 	default:
 		return -ENOIOCTLCMD;
 	}
diff --git a/fs/ocfs2/ocfs2_ioctl.h b/fs/ocfs2/ocfs2_ioctl.h
index 2d3420a..74c7566 100644
--- a/fs/ocfs2/ocfs2_ioctl.h
+++ b/fs/ocfs2/ocfs2_ioctl.h
@@ -76,4 +76,94 @@ 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 */
+};
+
+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;
+};
+
+struct ocfs2_info_blocksize {
+	struct ocfs2_info_request ib_req;
+	__u32 ib_blocksize;
+};
+
+struct ocfs2_info_maxslots {
+	struct ocfs2_info_request im_req;
+	__u16 im_max_slots;
+};
+
+struct ocfs2_info_label {
+	struct ocfs2_info_request il_req;
+	__u8	il_label[OCFS2_MAX_VOL_LABEL_LEN];
+};
+
+struct ocfs2_info_uuid {
+	struct ocfs2_info_request iu_req;
+	__u8	iu_uuid_str[OCFS2_TEXT_UUID_LEN + 1];
+};
+
+struct ocfs2_info_fs_features {
+	struct ocfs2_info_request if_req;
+	__u32 if_compat_features;
+	__u32 if_incompat_features;
+	__u32 if_ro_compat_features;
+};
+
+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 */
-- 
1.5.5

Ocfs2 devel - Apr 2010 - [PATCH 1/1] Ocfs2: Add new OCFS2_IOC_INFO ioctl for ocfs2 v7.

[Ocfs2-devel] [PATCH 1/1] Ocfs2: Add new OCFS2_IOC_INFO ioctl for ocfs2 v7.

[Ocfs2-devel] [PATCH 1/1] Ocfs2: Add new OCFS2_IOC_INFO ioctl for ocfs2 v7.

[Ocfs2-devel] [PATCH 1/1] Ocfs2: Add new OCFS2_IOC_INFO ioctl for ocfs2 v7.

[Ocfs2-devel] [PATCH 1/1] Ocfs2: Add new OCFS2_IOC_INFO ioctl for ocfs2 v7.

[Ocfs2-devel] [PATCH 1/1] Ocfs2: Add new OCFS2_IOC_INFO ioctl for ocfs2 v7.

[Ocfs2-devel] [PATCH 1/1] Ocfs2: Add new OCFS2_IOC_INFO ioctl for ocfs2 v7.