On Fri 26-10-12 18:35:24, Darrick J. Wong wrote:
> This creates BDI_CAP_STABLE_WRITES, which indicates that a device requires
> stable page writes. It also plumbs in a sysfs attribute so that admins can
> check the device status.
>
> Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
I guess Jens Axboe <axboe@xxxxxxxxx> would be the best target for this
patch (so that he can merge it). The patch looks OK to me. You can add:
Reviewed-by: Jan Kara <jack@xxxxxxx>
Honza
> ---
>
> block/blk-integrity.c | 8 ++++++++
> include/linux/backing-dev.h | 6 ++++++
> mm/backing-dev.c | 11 +++++++++++
> 3 files changed, 25 insertions(+)
>
> diff --git a/block/blk-integrity.c b/block/blk-integrity.c
> index da2a818..d05d7b3 100644
> --- a/block/blk-integrity.c
> +++ b/block/blk-integrity.c
> @@ -384,6 +384,7 @@ EXPORT_SYMBOL(blk_integrity_is_initialized);
> int blk_integrity_register(struct gendisk *disk, struct blk_integrity *template)
> {
> struct blk_integrity *bi;
> + struct backing_dev_info *bdi;
>
> BUG_ON(disk == NULL);
>
> @@ -420,6 +421,9 @@ int blk_integrity_register(struct gendisk *disk, struct blk_integrity *template)
> } else
> bi->name = bi_unsupported_name;
>
> + bdi = &disk->queue->backing_dev_info;
> + bdi->capabilities |= BDI_CAP_STABLE_WRITES;
> +
> return 0;
> }
> EXPORT_SYMBOL(blk_integrity_register);
> @@ -434,10 +438,14 @@ EXPORT_SYMBOL(blk_integrity_register);
> void blk_integrity_unregister(struct gendisk *disk)
> {
> struct blk_integrity *bi;
> + struct backing_dev_info *bdi;
>
> if (!disk || !disk->integrity)
> return;
>
> + bdi = &disk->queue->backing_dev_info;
> + bdi->capabilities &= ~BDI_CAP_STABLE_WRITES;
> +
> bi = disk->integrity;
>
> kobject_uevent(&bi->kobj, KOBJ_REMOVE);
> diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h
> index 2a9a9ab..b82a8bb 100644
> --- a/include/linux/backing-dev.h
> +++ b/include/linux/backing-dev.h
> @@ -253,6 +253,7 @@ int bdi_set_max_ratio(struct backing_dev_info *bdi, unsigned int max_ratio);
> #define BDI_CAP_EXEC_MAP 0x00000040
> #define BDI_CAP_NO_ACCT_WB 0x00000080
> #define BDI_CAP_SWAP_BACKED 0x00000100
> +#define BDI_CAP_STABLE_WRITES 0x00000200
>
> #define BDI_CAP_VMFLAGS \
> (BDI_CAP_READ_MAP | BDI_CAP_WRITE_MAP | BDI_CAP_EXEC_MAP)
> @@ -307,6 +308,11 @@ long wait_iff_congested(struct zone *zone, int sync, long timeout);
> int pdflush_proc_obsolete(struct ctl_table *table, int write,
> void __user *buffer, size_t *lenp, loff_t *ppos);
>
> +static inline bool bdi_cap_stable_writes(struct backing_dev_info *bdi)
> +{
> + return bdi->capabilities & BDI_CAP_STABLE_WRITES;
> +}
> +
> static inline bool bdi_cap_writeback_dirty(struct backing_dev_info *bdi)
> {
> return !(bdi->capabilities & BDI_CAP_NO_WRITEBACK);
> diff --git a/mm/backing-dev.c b/mm/backing-dev.c
> index d3ca2b3..a2f4c08 100644
> --- a/mm/backing-dev.c
> +++ b/mm/backing-dev.c
> @@ -221,12 +221,23 @@ static ssize_t max_ratio_store(struct device *dev,
> }
> BDI_SHOW(max_ratio, bdi->max_ratio)
>
> +static ssize_t stable_page_writes_show(struct device *dev,
> + struct device_attribute *attr, char *page)
> +{
> + struct backing_dev_info *bdi = dev_get_drvdata(dev);
> +
> + return snprintf(page, PAGE_SIZE-1, "%d\n",
> + bdi->capabilities & BDI_CAP_STABLE_WRITES ? 1 : 0);
> +}
> +
> #define __ATTR_RW(attr) __ATTR(attr, 0644, attr##_show, attr##_store)
> +#define __ATTR_RO(attr) __ATTR(attr, 0444, attr##_show, NULL)
>
> static struct device_attribute bdi_dev_attrs[] = {
> __ATTR_RW(read_ahead_kb),
> __ATTR_RW(min_ratio),
> __ATTR_RW(max_ratio),
> + __ATTR_RO(stable_page_writes),
> __ATTR_NULL,
> };
>
> --
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--
Jan Kara <jack@xxxxxxx>
SUSE Labs, CR
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