[Ocfs2-devel] [PATCH 1/1] Ocfs2: Add new OCFS2_IOC_INFO ioctl for ocfs2 v7.
Sunil Mushran
sunil.mushran at oracle.com
Mon Apr 19 13:16:28 PDT 2010
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 */
>
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