On Mon, Jan 30, 2017 at 07:59:50PM +0100, Artur Paszkiewicz wrote:
> Add 'consistency_policy' attribute for array. It indicates how the array
> maintains consistency in case of unexpected shutdown.
>
> Add 'ppl_sector' and 'ppl_size' for rdev, which describe the location
> and size of the PPL space on the device.
>
> These attributes are writable to allow enabling PPL for external
> metadata arrays and (later) to enable/disable PPL for a running array.
>
> Signed-off-by: Artur Paszkiewicz <artur.paszkiewicz@xxxxxxxxx>
> ---
> Documentation/admin-guide/md.rst | 32 ++++++++++-
> drivers/md/md.c | 115 +++++++++++++++++++++++++++++++++++++++
> 2 files changed, 144 insertions(+), 3 deletions(-)
>
> diff --git a/Documentation/admin-guide/md.rst b/Documentation/admin-guide/md.rst
> index 7104ef757e73..2c153b3d798f 100644
> --- a/Documentation/admin-guide/md.rst
> +++ b/Documentation/admin-guide/md.rst
> @@ -329,14 +329,14 @@ All md devices contain:
> array creation it will default to 0, though starting the array as
> ``clean`` will set it much larger.
>
> - new_dev
> + new_dev
> This file can be written but not read. The value written should
> be a block device number as major:minor. e.g. 8:0
> This will cause that device to be attached to the array, if it is
> available. It will then appear at md/dev-XXX (depending on the
> name of the device) and further configuration is then possible.
>
> - safe_mode_delay
> + safe_mode_delay
> When an md array has seen no write requests for a certain period
> of time, it will be marked as ``clean``. When another write
> request arrives, the array is marked as ``dirty`` before the write
> @@ -345,7 +345,7 @@ All md devices contain:
> period as a number of seconds. The default is 200msec (0.200).
> Writing a value of 0 disables safemode.
>
> - array_state
> + array_state
> This file contains a single word which describes the current
> state of the array. In many cases, the state can be set by
> writing the word for the desired state, however some states
> @@ -454,7 +454,30 @@ All md devices contain:
> once the array becomes non-degraded, and this fact has been
> recorded in the metadata.
>
> + consistency_policy
> + This indicates how the array maintains consistency in case of unexpected
> + shutdown. It can be:
>
> + none
> + Array has no redundancy information, e.g. raid0, linear.
> +
> + resync
> + Full resync is performed and all redundancy is regenerated when the
> + array is started after unclean shutdown.
> +
> + bitmap
> + Resync assisted by a write-intent bitmap.
> +
> + journal
> + For raid4/5/6, journal device is used to log transactions and replay
> + after unclean shutdown.
> +
> + ppl
> + For raid5 only, :ref:`ppl` is used to close the write hole and eliminate
> + resync.
> +
> + The accepted values when writing to this file are ``ppl`` and ``resync``,
> + used to enable and disable PPL.
>
>
> As component devices are added to an md array, they appear in the ``md``
> @@ -616,6 +639,9 @@ Each directory contains:
> adds bad blocks without acknowledging them. This is largely
> for testing.
>
> + ppl_sector, ppl_size
> + Location and size (in sectors) of the space used for Partial Parity Log
> + on this device.
>
>
> An active md device will also contain an entry for each active device
> diff --git a/drivers/md/md.c b/drivers/md/md.c
> index e96f73572e23..47ab3afe87cb 100644
> --- a/drivers/md/md.c
> +++ b/drivers/md/md.c
> @@ -3205,6 +3205,78 @@ static ssize_t ubb_store(struct md_rdev *rdev, const char *page, size_t len)
> static struct rdev_sysfs_entry rdev_unack_bad_blocks =
> __ATTR(unacknowledged_bad_blocks, S_IRUGO|S_IWUSR, ubb_show, ubb_store);
>
> +static ssize_t
> +ppl_sector_show(struct md_rdev *rdev, char *page)
> +{
> + return sprintf(page, "%llu\n", (unsigned long long)rdev->ppl.sector);
> +}
> +
> +static ssize_t
> +ppl_sector_store(struct md_rdev *rdev, const char *buf, size_t len)
> +{
> + unsigned long long sector;
> +
> + if (kstrtoull(buf, 10, §or) < 0)
> + return -EINVAL;
> + if (sector != (sector_t)sector)
> + return -EINVAL;
> +
> + if (rdev->mddev->pers && test_bit(MD_HAS_PPL, &rdev->mddev->flags) &&
> + rdev->raid_disk >= 0)
> + return -EBUSY;
> +
> + if (rdev->mddev->persistent) {
> + if (rdev->mddev->major_version == 0)
> + return -EINVAL;
> + if ((sector > rdev->sb_start &&
> + sector - rdev->sb_start > S16_MAX) ||
> + (sector < rdev->sb_start &&
> + rdev->sb_start - sector > -S16_MIN))
> + return -EINVAL;
> + rdev->ppl.offset = sector - rdev->sb_start;
Why do we allow non-external array changes the ppl log position and size?
> + } else if (!rdev->mddev->external) {
> + return -EBUSY;
> + }
> + rdev->ppl.sector = sector;
> + return len;
> +}
> +
> +static struct rdev_sysfs_entry rdev_ppl_sector =
> +__ATTR(ppl_sector, S_IRUGO|S_IWUSR, ppl_sector_show, ppl_sector_store);
> +
> +static ssize_t
> +ppl_size_show(struct md_rdev *rdev, char *page)
> +{
> + return sprintf(page, "%u\n", rdev->ppl.size);
> +}
> +
> +static ssize_t
> +ppl_size_store(struct md_rdev *rdev, const char *buf, size_t len)
> +{
> + unsigned int size;
> +
> + if (kstrtouint(buf, 10, &size) < 0)
> + return -EINVAL;
> +
> + if (rdev->mddev->pers && test_bit(MD_HAS_PPL, &rdev->mddev->flags) &&
> + rdev->raid_disk >= 0)
> + return -EBUSY;
> +
> + if (rdev->mddev->persistent) {
> + if (rdev->mddev->major_version == 0)
> + return -EINVAL;
> + if (size > U16_MAX)
> + return -EINVAL;
> + } else if (!rdev->mddev->external) {
> + return -EBUSY;
> + }
> + rdev->ppl.size = size;
> + return len;
> +}
> +
> +static struct rdev_sysfs_entry rdev_ppl_size =
> +__ATTR(ppl_size, S_IRUGO|S_IWUSR, ppl_size_show, ppl_size_store);
> +
> static struct attribute *rdev_default_attrs[] = {
> &rdev_state.attr,
> &rdev_errors.attr,
> @@ -3215,6 +3287,8 @@ static struct attribute *rdev_default_attrs[] = {
> &rdev_recovery_start.attr,
> &rdev_bad_blocks.attr,
> &rdev_unack_bad_blocks.attr,
> + &rdev_ppl_sector.attr,
> + &rdev_ppl_size.attr,
> NULL,
> };
> static ssize_t
> @@ -4951,6 +5025,46 @@ static struct md_sysfs_entry md_array_size =
> __ATTR(array_size, S_IRUGO|S_IWUSR, array_size_show,
> array_size_store);
>
> +static ssize_t
> +consistency_policy_show(struct mddev *mddev, char *page)
> +{
> + int ret;
> +
> + if (test_bit(MD_HAS_JOURNAL, &mddev->flags)) {
> + ret = sprintf(page, "journal\n");
> + } else if (test_bit(MD_HAS_PPL, &mddev->flags)) {
> + ret = sprintf(page, "ppl\n");
> + } else if (mddev->bitmap) {
> + ret = sprintf(page, "bitmap\n");
> + } else if (mddev->pers) {
> + if (mddev->pers->sync_request)
> + ret = sprintf(page, "resync\n");
> + else
> + ret = sprintf(page, "none\n");
> + } else {
> + ret = sprintf(page, "unknown\n");
> + }
> +
> + return ret;
> +}
> +
> +static ssize_t
> +consistency_policy_store(struct mddev *mddev, const char *buf, size_t len)
> +{
> + if (mddev->pers) {
> + return -EBUSY;
> + } else if (mddev->external && strncmp(buf, "ppl", 3) == 0) {
> + set_bit(MD_HAS_PPL, &mddev->flags);
> + return len;
Here we should check if ppl position and size are valid before we set the flag.
And shouldn't we move this part to .change_consistency_policy added in patch 9?
This is a consistency policy change too.
Thanks,
Shaohua
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