On Fri, Jun 06, 2014 at 09:13:32AM -0400, Brian Foster wrote:
> Embed a kobject into the xfs log data structure (xlog). This creates a
> 'log' subdirectory for every XFS mount instance in sysfs. The lifecycle
> of the log kobject is tied to the lifecycle of the log.
>
> Also define a set of generic attribute handlers associated with the log
> kobject in preparation for the addition of attributes.
The code works fine, but....
>
> Signed-off-by: Brian Foster <bfoster@xxxxxxxxxx>
> ---
> fs/xfs/xfs_log.c | 9 +++++++++
> fs/xfs/xfs_log_priv.h | 3 +++
> fs/xfs/xfs_sysfs.c | 53 +++++++++++++++++++++++++++++++++++++++++++++++++++
> fs/xfs/xfs_sysfs.h | 1 +
> 4 files changed, 66 insertions(+)
>
> diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c
> index 292308d..8eb10d5 100644
> --- a/fs/xfs/xfs_log.c
> +++ b/fs/xfs/xfs_log.c
> @@ -34,6 +34,7 @@
> #include "xfs_trace.h"
> #include "xfs_fsops.h"
> #include "xfs_cksum.h"
> +#include "xfs_sysfs.h"
>
> kmem_zone_t *xfs_log_ticket_zone;
>
> @@ -707,6 +708,11 @@ xfs_log_mount(
> }
> }
>
> + error = xfs_sysfs_init(&mp->m_log->l_kobject, &xfs_log_ktype,
> + &mp->m_log->l_kobject_complete, &mp->m_kobject, "log");
> + if (error)
> + goto out_destroy_ail;
... that's, ummm, rather verbose. At minimum, a local log variable,
but I suspect that if the pattern of "all sysfs dirs have a kobject
and a completion" and they are always used together that maybe
we should have a:
struct xfs_kobj {
struct kobject kobj;
struct completion complete;
};
And we pass them around instead. that would make this:
error = xfs_sysfs_init(&log->l_kobj, &xfs_log_ktype,
&mp->m_kobj, "log");
which is much easier to read....
> +
> /* Normal transactions can now occur */
> mp->m_log->l_flags &= ~XLOG_ACTIVE_RECOVERY;
>
> @@ -947,6 +953,9 @@ xfs_log_unmount(
> xfs_log_quiesce(mp);
>
> xfs_trans_ail_destroy(mp);
> +
> + xfs_sysfs_del(&mp->m_log->l_kobject, &mp->m_log->l_kobject_complete);
And that would become:
xfs_sysfs_del(&log->l_kobj);
> +
> xlog_dealloc_log(mp->m_log);
> }
>
> diff --git a/fs/xfs/xfs_log_priv.h b/fs/xfs/xfs_log_priv.h
> index 9bc403a..ce1eee2 100644
> --- a/fs/xfs/xfs_log_priv.h
> +++ b/fs/xfs/xfs_log_priv.h
> @@ -405,6 +405,9 @@ struct xlog {
> struct xlog_grant_head l_reserve_head;
> struct xlog_grant_head l_write_head;
>
> + struct kobject l_kobject;
> + struct completion l_kobject_complete;
struct xfs_kobj l_kobj;
> +
> /* The following field are used for debugging; need to hold icloglock */
> #ifdef DEBUG
> char *l_iclog_bak[XLOG_MAX_ICLOGS];
> diff --git a/fs/xfs/xfs_sysfs.c b/fs/xfs/xfs_sysfs.c
> index 41365fe..f837527 100644
> --- a/fs/xfs/xfs_sysfs.c
> +++ b/fs/xfs/xfs_sysfs.c
> @@ -54,3 +54,56 @@ xfs_mp_release(struct kobject *kobj)
> struct kobj_type xfs_mp_ktype = {
> .release = xfs_mp_release,
> };
> +
> +/* xlog */
> +
> +static struct attribute *xfs_log_attrs[] = {
> + NULL,
> +};
> +
> +STATIC ssize_t
> +xfs_log_show(
> + struct kobject *kobj,
> + struct attribute *attr,
> + char *buf)
> +{
> + struct xlog *log = container_of(kobj, struct xlog, l_kobject);
> + struct xfs_sysfs_attr *xfs_attr = container_of(attr,
> + struct xfs_sysfs_attr, attr);
> +
> + return xfs_attr->show ? xfs_attr->show(buf, log) : 0;
I think this could be made much less verbose:
static inline struct xlog *
to_xlog(struct kobject *kobj)
{
return container_of(...)
}
static inline struct xfs_sysfs_attr *
to_attr(struct attribute *attr)
{
return container_of(...)
}
so this becomes:
{
struct xlog *log = to_xlog(kobj);
struct xfs_sysfs_attr *attr = to_attr(kattr);
return attr->show ? attr->show(buf, log) : 0;
}
> +}
> +
> +STATIC ssize_t
> +xfs_log_store(
> + struct kobject *kobj,
> + struct attribute *attr,
> + const char *buf,
> + size_t count)
> +{
> + struct xlog *log = container_of(kobj, struct xlog, l_kobject);
> + struct xfs_sysfs_attr *xfs_attr = container_of(attr,
> + struct xfs_sysfs_attr, attr);
> +
> + return xfs_attr->store ? xfs_attr->store(buf, count, log) : 0;
> +}
> +
> +static struct sysfs_ops xfs_log_ops = {
> + .show = xfs_log_show,
> + .store = xfs_log_store,
> +};
> +
> +STATIC void
> +xfs_log_release(struct kobject *kobj)
> +{
> + struct xlog *log = container_of(kobj, struct xlog, l_kobject);
> +
> + complete(&log->l_kobject_complete);
> +}
If the release funtion is common with other types, then the xfs_kobj
structure is perfect for this use - it will prevent a heap of
duplicated release functions...
Cheers,
Dave.
--
Dave Chinner
david@xxxxxxxxxxxxx
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