Re: [Qemu-devel] [PATCH] add CephFS support in VirtFS

[Jevon Qiao <scaleqiao@gmail.com>]

Hi Daniel,

Thank you for reviewing my code, please see my reply in-line.
On 15/2/16 17:17, Daniel P. Berrange wrote:
> On Sun, Feb 14, 2016 at 01:06:40PM +0800, Jevon Qiao wrote:
>> diff --git a/configure b/configure
>> index 83b40fc..cecece7 100755
>> --- a/configure
>> +++ b/configure
>> @@ -1372,6 +1377,7 @@ disabled with --disable-FEATURE, default is enabled if
>> available:
>>     vhost-net       vhost-net acceleration support
>>     spice           spice
>>     rbd             rados block device (rbd)
>> +  cephfs      Ceph File System
> Inconsistent vertical alignment with surrounding text
This is just a display issue, I'll send the patch with 'git send-email' 
later after I address all the technical comments.
>>     libiscsi        iscsi support
>>     libnfs          nfs support
>>     smartcard       smartcard support (libcacard)
>> +/*
>> + * Helper function for cephfs_preadv and cephfs_pwritev
>> + */
>> +inline static ssize_t preadv_pwritev(struct ceph_mount_info *cmount, int
>> fd,
> Your email client is mangling long lines, here and in many other
> places in the file. Please either fix your email client to not
> insert arbitrary line breaks, or use git send-email to submit
> the patch.
Ditto.
>> +                              const struct iovec *iov, int iov_cnt,
>> +                              off_t offset, bool do_write)
>> +{
>> +    ssize_t ret = 0;
>> +    int i = 0;
> Use size_t for iterators
I'll revise the code.
>> +    size_t len = 0;
>> +    void *buf, *buftmp;
>> +    size_t bufoffset = 0;
>> +
>> +    for (; i < iov_cnt; i++) {
>> +        len += iov[i].iov_len;
>> +    }
> iov_size() does this calculation
Thanks for the suggestion.
>> +
>> +    buf = malloc(len);
> Use g_new0(uint8_t, len)
OK.
>> +    if (buf == NULL) {
>> +        errno = ENOMEM;
>> +        return -1;
>> +    }
> and don't check ENOMEM;
Any reason for this?
>> +
>> +    i = 0;
>> +    buftmp = buf;
>> +    if (do_write) {
>> +        for (i = 0; i < iov_cnt; i++) {
>> +            memcpy((buftmp + bufoffset), iov[i].iov_base, iov[i].iov_len);
>> +            bufoffset += iov[i].iov_len;
>> +        }
>> +        ret = ceph_write(cmount, fd, buf, len, offset);
>> +        if (ret <= 0) {
>> +           errno = -ret;
>> +           ret = -1;
>> +        }
>> +    } else {
>> +        ret = ceph_read(cmount, fd, buf, len, offset);
>> +        if (ret <= 0) {
>> +            errno = -ret;
>> +            ret = -1;
>> +        } else {
>> +            for (i = 0; i < iov_cnt; i++) {
>> +                memcpy(iov[i].iov_base, (buftmp + bufoffset),
>> iov[i].iov_len);
> Mangled long line again.
That's the email client issue.
>> +                bufoffset += iov[i].iov_len;
>> +            }
>> +        }
>> +    }
>> +
>> +    free(buf);
>> +    return ret;
>> +}
>> +
>> +static int cephfs_update_file_cred(struct ceph_mount_info *cmount,
>> +                   const char *name, FsCred *credp)
> Align the parameters on following line to the '('
I will revise the code.
>> +{
>> +    int fd, ret;
>> +    fd = ceph_open(cmount, name, O_NONBLOCK | O_NOFOLLOW, credp->fc_mode);
>> +    if (fd < 0) {
>> +        return fd;
>> +    }
>> +    ret = ceph_fchown(cmount, fd, credp->fc_uid, credp->fc_gid);
>> +    if (ret < 0) {
>> +        goto err_out;
>> +    }
>> +    ret = ceph_fchmod(cmount, fd, credp->fc_mode & 07777);
>> +err_out:
>> +    close(fd);
>> +    return ret;
>> +}
>> +
>> +static int cephfs_lstat(FsContext *fs_ctx, V9fsPath *fs_path,
>> +                        struct stat *stbuf)
>> +{
>> +    D_CEPHFS("cephfs_lstat");
> All of these D_CEPHFS() lines you have are really inserting trace
> points, so you should really use the QEMU trace facility instead
> of a fprintf() based macro. ie add to trace-events and then
> call the generated trace fnuction for your event. Then get rid
> of your D_CEPHFS macro.
I will revise the code.
>> +    int ret;
>> +    char *path = fs_path->data;
>> +    struct cephfs_data *cfsdata = (struct cephfs_data *)fs_ctx->private;
> fs_ctx->private is 'void *' so you don't need the (struct cephfs_data *)
> cast there - 'void *' casts to anything automatically. The same issue
> in all the other functions below too.
OK, I see.
>> +    ret = ceph_lstat(cfsdata->cmount, path, stbuf);
>> +    if (ret){
>> +        errno = -ret;
>> +        ret = -1;
>> +    }
>> +    return ret;
>> +}
>> +
>> +static ssize_t cephfs_readlink(FsContext *fs_ctx, V9fsPath *fs_path,
>> +                               char *buf, size_t bufsz)
>> +{
>> +    D_CEPHFS("cephfs_readlink");
>> +    int ret;
>> +    char *path = fs_path->data;
>> +    struct cephfs_data *cfsdata = (struct cephfs_data *)fs_ctx->private;
>> +
>> +    ret = ceph_readlink(cfsdata->cmount, path, buf, bufsz);
>> +    return ret;
>> +}
>> +
>> +static int cephfs_close(FsContext *ctx, V9fsFidOpenState *fs)
>> +{
>> +    D_CEPHFS("cephfs_close");
>> +    struct cephfs_data *cfsdata = (struct cephfs_data*)ctx->private;
>> +
>> +    return ceph_close(cfsdata->cmount, fs->fd);
>> +}
>> +
>> +static int cephfs_closedir(FsContext *ctx, V9fsFidOpenState *fs)
>> +{
>> +    D_CEPHFS("cephfs_closedir");
>> +    struct cephfs_data *cfsdata = (struct cephfs_data*)ctx->private;
>> +
>> +    return ceph_closedir(cfsdata->cmount, (struct ceph_dir_result
>> *)fs->dir);
>> +}
>> +
>> +static int cephfs_open(FsContext *ctx, V9fsPath *fs_path,
>> +                       int flags, V9fsFidOpenState *fs)
>> +{
>> +    D_CEPHFS("cephfs_open");
>> +    struct cephfs_data *cfsdata = (struct cephfs_data *)ctx->private;
>> +
>> +    fs->fd = ceph_open(cfsdata->cmount, fs_path->data, flags, 0777);
>> +    return fs->fd;
>> +}
>> +
>> +static int cephfs_opendir(FsContext *ctx,
>> +                          V9fsPath *fs_path, V9fsFidOpenState *fs)
>> +{
>> +    D_CEPHFS("cephfs_opendir");
>> +    int ret;
>> +    //char buffer[PATH_MAX];
> Remove this if its really not needed
Sure.
>> +    struct ceph_dir_result *result;
>> +    struct cephfs_data *cfsdata = (struct cephfs_data*)ctx->private;
>> +    char *path = fs_path->data;
>> +
>> +    ret = ceph_opendir(cfsdata->cmount, path, &result);
>> +    if (ret) {
>> +        fprintf(stderr, "ceph_opendir=%d\n", ret);
> Don't put in bare printfs in the code.
OK, I'll revise the code.
>> +        return ret;
>> +    }
>> +    fs->dir = (DIR *)result;
>> +    if (!fs->dir) {
>> +        fprintf(stderr, "ceph_opendir return NULL for ceph_dir_result\n");
>> +        return -1;
>> +    }
>> +    return 0;
>> +}
>> +
>> +static void cephfs_rewinddir(FsContext *ctx, V9fsFidOpenState *fs)
>> +{
>> +    D_CEPHFS("cephfs_rewinddir");
>> +    struct cephfs_data *cfsdata = (struct cephfs_data *)ctx->private;
>> +
>> +    return ceph_rewinddir(cfsdata->cmount, (struct ceph_dir_result
>> *)fs->dir);
>> +}
>> +
>> +static off_t cephfs_telldir(FsContext *ctx, V9fsFidOpenState *fs)
>> +{
>> +    D_CEPHFS("cephfs_telldir");
>> +    int ret;
>> +    struct cephfs_data *cfsdata = (struct cephfs_data *)ctx->private;
>> +
>> +    ret = ceph_telldir(cfsdata->cmount, (struct ceph_dir_result *)fs->dir);
>> +    return ret;
>> +}
>> +
>> +static int cephfs_readdir_r(FsContext *ctx, V9fsFidOpenState *fs,
>> +                            struct dirent *entry,
>> +                            struct dirent **result)
>> +{
>> +    D_CEPHFS("cephfs_readdir_r");
>> +    int ret;
>> +    struct dirent *tmpent;
>> +    struct cephfs_data *cfsdata = (struct cephfs_data *)ctx->private;
>> +
>> +    tmpent = entry;
>> +    ret = ceph_readdir_r(cfsdata->cmount, (struct ceph_dir_result
>> *)fs->dir,
>> +                entry);
>> +    if (ret > 0 && entry != NULL)
>> +    {
>> +        *result = entry;
>> +    } else if (!ret)
>> +    {
>> +        *result = NULL;
>> +        entry = tmpent;
>> +    }
>> +
>> +    return ret;
>> +}
>> +
>> +static void cephfs_seekdir(FsContext *ctx, V9fsFidOpenState *fs, off_t off)
>> +{
>> +    D_CEPHFS("cephfs_seekdir");
>> +    struct cephfs_data *cfsdata = (struct cephfs_data *)ctx->private;
>> +
>> +    return ceph_seekdir(cfsdata->cmount, (struct ceph_dir_result*)fs->dir,
>> off);
>> +}
>> +
>> +static ssize_t cephfs_preadv(FsContext *ctx, V9fsFidOpenState *fs,
>> +                             const struct iovec *iov,
>> +                             int iovcnt, off_t offset)
>> +{
>> +    D_CEPHFS("cephfs_preadv");
>> +    ssize_t ret = 0;
>> +    struct cephfs_data *cfsdata = (struct cephfs_data *)ctx->private;
>> +
>> +#if defined(LIBCEPHFS_VERSION) && LIBCEPHFS_VERSION_CODE >=
>> LIBCEPHFS_VERSION(9,
>> +    0, 3)
>> +    ret = ceph_preadv(cfsdata->cmount, fs->fd, iov, iovcnt, offset);
>> +#else
>> +    if (iovcnt > 1) {
>> +    ret = preadv_pwritev(cfsdata->cmount, fs->fd, iov, iovcnt, offset, 0);
>> +    } else if (iovcnt > 0) {
>> +    ret = ceph_read(cfsdata->cmount, fs->fd, iov[0].iov_base,
>> +            iov[0].iov_len, offset);
>> +    }
> Indent lines inside the if() statement
That's a display issue, I will fix the format by sending patches with 
'git send-email'
>> +#endif
>> +
>> +    return ret;
>> +}
>> +
>> +static ssize_t cephfs_pwritev(FsContext *ctx, V9fsFidOpenState *fs,
>> +                              const struct iovec *iov,
>> +                              int iovcnt, off_t offset)
>> +{
>> +    D_CEPHFS("cephfs_pwritev");
>> +    ssize_t ret = 0;
>> +    struct cephfs_data *cfsdata = (struct cephfs_data *)ctx->private;
>> +
>> +#if defined(LIBCEPHFS_VERSION) && LIBCEPHFS_VERSION_CODE >=
>> LIBCEPHFS_VERSION(9,
>> +    0, 3)
>> +    ret = ceph_pwritev(cfsdata->cmount, fs->fd, iov, iovcnt, offset);
>> +#else
>> +    if (iovcnt > 1) {
>> +    ret = preadv_pwritev(cfsdata->cmount, fs->fd, iov, iovcnt, offset, 1);
>> +    } else if (iovcnt > 0) {
>> +    ret = ceph_write(cfsdata->cmount, fs->fd, iov[0].iov_base,
>> +            iov[0].iov_len, offset);
>> +    }
> Indent lines inside the if() statement
Ditto.
>> +#endif
>> +
>> +#ifdef CONFIG_SYNC_FILE_RANGE
>> +    if (ret > 0 && ctx->export_flags & V9FS_IMMEDIATE_WRITEOUT) {
>> +        /*
>> +         * Initiate a writeback. This is not a data integrity sync.
>> +         * We want to ensure that we don't leave dirty pages in the cache
>> +         * after write when writeout=immediate is sepcified.
>> +         */
>> +        sync_file_range(fs->fd, offset, ret,
>> +                        SYNC_FILE_RANGE_WAIT_BEFORE |
>> SYNC_FILE_RANGE_WRITE);
>> +    }
>> +#endif
>> +    return ret;
>> +}
>> +
>> +static int cephfs_chmod(FsContext *fs_ctx, V9fsPath *fs_path, FsCred
>> *credp)
>> +{
>> +    D_CEPHFS("cephfs_chmod");
>> +    int  ret = -1;
>> +    struct cephfs_data *cfsdata = (struct cephfs_data *)fs_ctx->private;
>> +
>> +    ret = ceph_chmod(cfsdata->cmount, fs_path->data, credp->fc_mode);
>> +    return ret;
>> +}
>> +
>> +static int cephfs_mknod(FsContext *fs_ctx, V9fsPath *dir_path,
>> +                       const char *name, FsCred *credp)
>> +{
>> +    D_CEPHFS("cephfs_mknod");
>> +    int ret;
>> +    V9fsString fullname;
>> +    struct cephfs_data *cfsdata = (struct cephfs_data *)fs_ctx->private;
>> +
>> +    v9fs_string_init(&fullname);
>> +    v9fs_string_sprintf(&fullname, "%s/%s", dir_path->data, name);
>> +    ret = ceph_mknod(cfsdata->cmount, fullname.data, credp->fc_mode,
>> +            credp->fc_rdev);
>> +
>> +    v9fs_string_free(&fullname);
>> +    return ret;
>> +}
>> +
>> +static int cephfs_mkdir(FsContext *fs_ctx, V9fsPath *dir_path,
>> +                       const char *name, FsCred *credp)
>> +{
>> +    D_CEPHFS("cephfs_mkdir");
>> +    int ret;
>> +    V9fsString fullname;
>> +    struct cephfs_data *cfsdata = (struct cephfs_data *)fs_ctx->private;
>> +
>> +    v9fs_string_init(&fullname);
>> +    v9fs_string_sprintf(&fullname, "%s/%s", dir_path->data, name);
>> +    ret = ceph_mkdir(cfsdata->cmount, fullname.data, credp->fc_mode);
>> +
>> +    v9fs_string_free(&fullname);
>> +    return ret;
>> +}
>> +
>> +static int cephfs_fstat(FsContext *fs_ctx, int fid_type,
>> +                        V9fsFidOpenState *fs, struct stat *stbuf)
>> +{
>> +    D_CEPHFS("cephfs_fstat");
>> +    int fd = -1;
>> +    struct cephfs_data *cfsdata = (struct cephfs_data *)fs_ctx->private;
>> +
>> +    if (fid_type == P9_FID_DIR) {
>> +        fd = dirfd(fs->dir);
>> +    } else {
>> +        fd = fs->fd;
>> +    }
>> +    return ceph_fstat(cfsdata->cmount, fd, stbuf);
>> +}
>> +
>> +static int cephfs_open2(FsContext *fs_ctx, V9fsPath *dir_path, const char
>> *name,
>> +                        int flags, FsCred *credp, V9fsFidOpenState *fs)
>> +{
>> +    D_CEPHFS("cephfs_open2");
>> +    int fd = -1, ret = -1;
>> +    V9fsString fullname;
>> +    struct cephfs_data *cfsdata = (struct cephfs_data *)fs_ctx->private;
>> +
>> +    v9fs_string_init(&fullname);
>> +    v9fs_string_sprintf(&fullname, "%s/%s", dir_path->data, name);
>> +    fd = ceph_open(cfsdata->cmount, fullname.data, flags, credp->fc_mode);
>> +    if (fd >= 0) {
>> +        /* After creating the file, need to set the cred */
>> +        ret = cephfs_update_file_cred(cfsdata->cmount, name, credp);
>> +        if (ret < 0) {
>> +            ceph_close(cfsdata->cmount, fd);
>> +            errno = -ret;
>> +            fd = ret;
>> +        } else {
>> +            fs->fd = fd;
>> +        }
>> +    } else {
>> +       errno = -fd;
>> +    }
>> +
>> +    v9fs_string_free(&fullname);
>> +    return fd;
>> +}
>> +
>> +static int cephfs_symlink(FsContext *fs_ctx, const char *oldpath,
>> +                          V9fsPath *dir_path, const char *name, FsCred
>> *credp)
>> +{
>> +    D_CEPHFS("cephfs_symlink");
>> +    int ret = -1;
>> +    V9fsString fullname;
>> +    struct cephfs_data *cfsdata = (struct cephfs_data *)fs_ctx->private;
>> +
>> +    v9fs_string_init(&fullname);
>> +    v9fs_string_sprintf(&fullname, "%s/%s", dir_path->data, name);
>> +    ret = ceph_symlink(cfsdata->cmount, oldpath, fullname.data);
>> +
>> +    v9fs_string_free(&fullname);
>> +    return ret;
>> +}
>> +
>> +static int cephfs_link(FsContext *ctx, V9fsPath *oldpath,
>> +                       V9fsPath *dirpath, const char *name)
>> +{
>> +    D_CEPHFS("cephfs_link");
>> +    int ret = -1;
>> +    V9fsString newpath;
>> +    struct cephfs_data *cfsdata = (struct cephfs_data *)ctx->private;
>> +
>> +    v9fs_string_init(&newpath);
>> +    v9fs_string_sprintf(&newpath, "%s/%s", dirpath->data, name);
>> +    ret = ceph_link(cfsdata->cmount, oldpath->data, newpath.data);
>> +
>> +    v9fs_string_free(&newpath);
>> +    return ret;
>> +}
>> +
>> +static int cephfs_truncate(FsContext *ctx, V9fsPath *fs_path, off_t size)
>> +{
>> +    D_CEPHFS("cephfs_truncate");
>> +    int ret = -1;
>> +    struct cephfs_data *cfsdata = (struct cephfs_data *)ctx->private;
>> +
>> +    ret = ceph_truncate(cfsdata->cmount, fs_path->data, size);
>> +
>> +    return ret;
>> +}
>> +
>> +static int cephfs_rename(FsContext *ctx, const char *oldpath,
>> +                         const char *newpath)
>> +{
>> +    D_CEPHFS("cephfs_rename");
>> +    int ret = -1;
>> +    struct cephfs_data *cfsdata = (struct cephfs_data *)ctx->private;
>> +
>> +    ret = ceph_rename(cfsdata->cmount, oldpath, newpath);
>> +    return ret;
>> +}
>> +
>> +static int cephfs_chown(FsContext *fs_ctx, V9fsPath *fs_path, FsCred
>> *credp)
>> +{
>> +    D_CEPHFS("cephfs_chown");
>> +    int ret = -1;
>> +    struct cephfs_data *cfsdata = (struct cephfs_data *)fs_ctx->private;
>> +
>> +    ret = ceph_chown(cfsdata->cmount, fs_path->data, credp->fc_uid,
>> +            credp->fc_gid);
>> +    return ret;
>> +}
>> +
>> +static int cephfs_utimensat(FsContext *ctx, V9fsPath *fs_path,
>> +                            const struct timespec *buf)
>> +{
>> +    D_CEPHFS("cephfs_utimensat");
>> +    int ret = -1;
>> +
>> +#ifdef CONFIG_UTIMENSAT
>> +    struct cephfs_data *cfsdata = (struct cephfs_data *)ctx->private;
>> +
>> +    ret = ceph_utime(cfsdata->cmount, fs_path->data, (struct utimbuf
>> *)buf);
>> +#else
>> +    ret = -1;
>> +    errno = ENOSYS;
>> +#endif
>> +
>> +    return ret;
>> +}
>> +
>> +static int cephfs_remove(FsContext *ctx, const char *path)
>> +{
>> +    D_CEPHFS("cephfs_remove");
>> +    errno = EOPNOTSUPP;
>> +    return -1;
>> +}
>> +
>> +static int cephfs_fsync(FsContext *ctx, int fid_type,
>> +                        V9fsFidOpenState *fs, int datasync)
>> +{
>> +    D_CEPHFS("cephfs_fsync");
>> +    int ret = -1, fd = -1;
>> +    struct cephfs_data *cfsdata = (struct cephfs_data *)ctx->private;
>> +
>> +    if (fid_type == P9_FID_DIR) {
>> +        fd = dirfd(fs->dir);
>> +    } else {
>> +        fd = fs->fd;
>> +    }
>> +
>> +    ret = ceph_fsync(cfsdata->cmount, fd, datasync);
>> +    return ret;
>> +}
>> +
>> +static int cephfs_statfs(FsContext *ctx, V9fsPath *fs_path,
>> +                         struct statfs *stbuf)
>> +{
>> +    D_CEPHFS("cephfs_statfs");
>> +    int ret;
>> +    char *path = fs_path->data;
>> +    struct cephfs_data *cfsdata = (struct cephfs_data *)ctx->private;
>> +
>> +    ret = ceph_statfs(cfsdata->cmount, path, (struct statvfs*)stbuf);
>> +    if (ret) {
>> +        fprintf(stderr, "ceph_statfs=%d\n", ret);
>> +    }
>> +
>> +    return ret;
>> +}
>> +
>> +/*
>> + * Get the extended attribute of normal file, if the path refer to a
>> symbolic
>> + * link, just return the extended attributes of the syslink rather than the
>> + * attributes of the link itself.
>> + */
>> +static ssize_t cephfs_lgetxattr(FsContext *ctx, V9fsPath *fs_path,
>> +                                const char *name, void *value, size_t size)
>> +{
>> +    D_CEPHFS("cephfs_lgetxattr");
>> +    int ret;
>> +    char *path = fs_path->data;
>> +    struct cephfs_data *cfsdata = (struct cephfs_data *)ctx->private;
>> +
>> +    ret = ceph_lgetxattr(cfsdata->cmount, path, name, value, size);
>> +    return ret;
>> +}
>> +
>> +static ssize_t cephfs_llistxattr(FsContext *ctx, V9fsPath *fs_path,
>> +                                 void *value, size_t size)
>> +{
>> +    D_CEPHFS("cephfs_llistxattr");
>> +    int ret = -1;
>> +    struct cephfs_data *cfsdata = (struct cephfs_data *)ctx->private;
>> +
>> +    ret = ceph_llistxattr(cfsdata->cmount, fs_path->data, value, size);
>> +    return ret;
>> +}
>> +
>> +static int cephfs_lsetxattr(FsContext *ctx, V9fsPath *fs_path, const char
>> *name,
>> +                            void *value, size_t size, int flags)
>> +{
>> +    D_CEPHFS("cephfs_lsetxattr");
>> +    int ret = -1;
>> +    struct cephfs_data *cfsdata = (struct cephfs_data *)ctx->private;
>> +
>> +    ret = ceph_lsetxattr(cfsdata->cmount, fs_path->data, name, value, size,
>> +    flags);
>> +    return ret;
>> +}
>> +
>> +static int cephfs_lremovexattr(FsContext *ctx, V9fsPath *fs_path,
>> +                               const char *name)
>> +{
>> +    D_CEPHFS("cephfs_lremovexattr");
>> +    int ret = -1;
>> +    struct cephfs_data *cfsdata = (struct cephfs_data *)ctx->private;
>> +
>> +    ret = ceph_lremovexattr(cfsdata->cmount, fs_path->data, name);
>> +    return ret;
>> +}
>> +
>> +static int cephfs_name_to_path(FsContext *ctx, V9fsPath *dir_path,
>> +                              const char *name, V9fsPath *target)
>> +{
>> +    D_CEPHFS("cephfs_name_to_path");
>> +    if (dir_path) {
>> +        v9fs_string_sprintf((V9fsString *)target, "%s/%s",
>> +                            dir_path->data, name);
>> +    } else {
>> +        /* if the path does not start from '/' */
>> +        v9fs_string_sprintf((V9fsString *)target, "%s", name);
>> +    }
>> +
>> +    /* Bump the size for including terminating NULL */
>> +    target->size++;
>> +    return 0;
>> +}
>> +
>> +static int cephfs_renameat(FsContext *ctx, V9fsPath *olddir,
>> +                           const char *old_name, V9fsPath *newdir,
>> +                           const char *new_name)
>> +{
>> +    D_CEPHFS("cephfs_renameat");
>> +    int ret = -1;
>> +    struct cephfs_data *cfsdata = (struct cephfs_data *)ctx->private;
>> +
>> +    ret = ceph_rename(cfsdata->cmount, old_name, new_name);
>> +    return ret;
>> +}
>> +
>> +static int cephfs_unlinkat(FsContext *ctx, V9fsPath *dir,
>> +                           const char *name, int flags)
>> +{
>> +    D_CEPHFS("cephfs_unlinkat");
>> +    int ret = 0;
>> +    char *path = dir->data;
>> +    struct stat fstat;
>> +    V9fsString fullname;
>> +    struct cephfs_data *cfsdata = (struct cephfs_data *)ctx->private;
>> +
>> +    v9fs_string_init(&fullname);
>> +    v9fs_string_sprintf(&fullname, "%s/%s", dir->data, name);
>> +    path = fullname.data;
>> +    /* determine which kind of file is being destroyed */
>> +    ret = ceph_lstat(cfsdata->cmount, path, &fstat);
>> +    if (!ret) {
>> +        switch (fstat.st_mode & S_IFMT) {
>> +        case S_IFDIR:
>> +            ret = ceph_rmdir(cfsdata->cmount, path);
>> +            break;
>> +
>> +        case S_IFBLK:
>> +        case S_IFCHR:
>> +        case S_IFIFO:
>> +        case S_IFLNK:
>> +        case S_IFREG:
>> +        case S_IFSOCK:
>> +            ret = ceph_unlink(cfsdata->cmount, path);
>> +            break;
>> +
>> +        default:
>> +            fprintf(stderr, "ceph_lstat unknown stmode\n");
>> +            break;
>> +        }
>> +    } else {
>> +        errno = -ret;
>> +        ret = -1;
>> +    }
>> +
>> +    v9fs_string_free(&fullname);
>> +    return ret;
>> +}
>> +
>> +/*
>> + * Do two things in the init function:
>> + * 1) Create a mount handle used by all cephfs interfaces.
>> + * 2) Invoke ceph_mount() to initialize a link between the client and
>> + *    ceph monitor
>> + */
>> +static int cephfs_init(FsContext *ctx)
>> +{
>> +    D_CEPHFS("cephfs_init");
>> +    int ret;
>> +    const char *ver = NULL;
>> +    struct cephfs_data *data = g_malloc(sizeof(struct cephfs_data));
>> +
>> +    if (data == NULL) {
>> +    errno = ENOMEM;
>> +    return -1;
>> +    }
>> +    memset(data, 0, sizeof(struct cephfs_data));
>> +    ret = ceph_create(&data->cmount, NULL);
>> +    if (ret) {
>> +        fprintf(stderr, "ceph_create=%d\n", ret);
>> +        goto err_out;
>> +    }
>> +
>> +    ret = ceph_conf_read_file(data->cmount, NULL);
>> +    if (ret) {
>> +        fprintf(stderr, "ceph_conf_read_file=%d\n", ret);
>> +        goto err_out;
>> +    }
>> +
>> +    ret = ceph_mount(data->cmount, ctx->fs_root);
>> +    if (ret) {
>> +        fprintf(stderr, "ceph_mount=%d\n", ret);
>> +        goto err_out;
>> +    } else {
>> +        ctx->private = data;
>> +    /* CephFS does not support FS_IOC_GETVERSIO */
>> +    ctx->exops.get_st_gen = NULL;
> Bad indent.
>
>> +        goto out;
>> +    }
>> +
>> +    ver = ceph_version(&data->major, &data->minor, &data->patch);
>> +    memcpy(data->ceph_version, ver, strlen(ver) + 1);
>> +
>> +err_out:
>> +    g_free(data);
>> +out:
>> +    return ret;
>> +}
>> +
>> +static int cephfs_parse_opts(QemuOpts *opts, struct FsDriverEntry *fse)
>> +{
>> +    const char *sec_model = qemu_opt_get(opts, "security_model");
>> +    const char *path = qemu_opt_get(opts, "path");
>> +
>> +    if (!sec_model) {
>> +        fprintf(stderr, "Invalid argument security_model specified with "
>> +        "cephfs fsdriver\n");
> Bad indent.
BTW, is there any tool I can use to check the coding style in Qemu?

Thanks,
Jevon
>> +        return -1;
>> +    }
>> +
>> +    if (!path) {
>> +        fprintf(stderr, "fsdev: No path specified.\n");
>> +        return -1;
>> +    }
>> +
>> +    fse->path = g_strdup(path);
>> +    return 0;
>> +}
> Regards,
> Daniel